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Materials
Number of Followers: 4  Open Access journalISSN (Print) 1996-1944 Published by MDPI  [258 journals]
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- Materials, Vol. 16, Pages 3983: The Efficient Way to Design Cooling
Sections for Heat Treatment of Long Steel Products
Authors: Petr Kotrbacek, Martin Chabicovsky, Ondrej Resl, Jan Kominek, Tomas Luks
First page: 3983
Abstract: To achieve the required mechanical properties in the heat treatment of steel, it is necessary to have an adequate cooling rate and to achieve the desired final temperature of the product. This should be achieved with one cooling unit for different product sizes. In order to provide the high variability of the cooling system, different types of nozzles are used in modern cooling systems. Designers often use simplified, inaccurate correlations to predict the heat transfer coefficient, resulting in the oversizing of the designed cooling system or failure to provide the required cooling regime. This typically results in longer commissioning times and higher manufacturing costs of the new cooling system. Accurate information about the required cooling regime and the heat transfer coefficient of the designed cooling is critical. This paper presents a design approach based on laboratory measurements. Firstly, the way to find or validate the required cooling regime is presented. The paper then focuses on nozzle selection and presents laboratory measurements that provide accurate heat transfer coefficients as a function of position and surface temperature for different cooling configurations. Numerical simulations using the measured heat transfer coefficients allow the optimum design to be found for different product sizes.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113983
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 3987: Effect of Annealing Temperature on the
Microstructure and Mechanical Properties of CoCrFeNiNb0.2Mo0.2 High
Entropy Alloy
Authors: Rui Fan, Sicong Zhao, Liping Wang, Lei Wang, Erjun Guo
First page: 3987
Abstract: Strengthening the CoCrFeNi high entropy alloy with a face-center cubic structure has become a research prospect in the last decade. Alloying with double elements, Nb and Mo, is an effective method. In this paper, to further enhance the strength of the Nb and Mo contained high entropy alloy, CoCrFeNiNb0.2Mo0.2 was annealing treated at different temperatures for 24 h. As a result, a new kind of Cr2Nb type nano-scale precipitate with a hexagonal close-packed structure was formed, which is semi-coherent with the matrix. Moreover, by adjusting the annealing temperature, the precipitate was tailored with a considerable quantity and fine size. The best overall mechanical properties were achieved in the alloy annealed at 700 °C. The yield strength, ultimate tensile strength, and elongation are 727 MPa, 1.05 GPa, and 8.38%, respectively. The fracture mode of the annealed alloy is a mixture of cleavage and necking-featured ductile fracture. The approach employed in this study offers a theoretical foundation for enhancing the mechanical properties of face-centered cubic high entropy alloys via annealing treatment.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113987
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 3988: Effect of Annealing Temperature on
Authors: Wei Pei, Shaoguang Yang, Kuo Cao, Aimin Zhao
First page: 3988
Abstract: Compared to Cr-Ni stainless steel, nickel-saving stainless steel is a low-cost austenitic stainless steel. We studied the deformation mechanism of stainless steel at various annealing temperatures (850 °C, 950 °C, and 1050 °C). The grain size of the specimen increases with increasing annealing temperature while the yield strength decreases, which follows the Hall–Petch equation. When plastic deformation occurs, dislocation increases. However, the deformation mechanisms can vary between different specimens. Stainless steel with smaller grains is more likely to transform into martensite when deformed. While twinning occurs when the grains are more prominent, the deformation results in twinning. The phase transformation during plastic deformation relies on the shear, so the orientation of the grains is relevant before and after plastic deformation.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113988
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 3989: Effect of Surface Modifications on Surface
Roughness of Ti6Al4V Alloy Manufactured by 3D Printing, Casting, and
Wrought
Authors: János Kónya, Hajnalka Hargitai, Hassanen Jaber, Péter Pinke, Tünde Anna Kovács
First page: 3989
Abstract: This work aimed to comprehensively evaluate the influence of different surface modifications on the surface roughness of Ti6Al4V alloys produced by selective laser melting (SLM), casting and wrought. The Ti6Al4V surface was treated using blasting with Al2O3 (70–100 µm) and ZrO2 (50–130 µm) particles, acid etching with 0.017 mol/dm3 hydrofluoric acids (HF) for 120 s, and a combination of blasting and acid etching (SLA). It was found that the optimization of the surface roughness of Ti6Al4V parts produced by SLM differs significantly from those produced by casting or wrought processes. Experimental results showed that Ti6Al4V alloys produced by SLM and blasting with Al2O3 followed by HF etching had a higher surface roughness (Ra = 2.043 µm, Rz = 11.742 µm), whereas cast and wrought Ti6Al4V components had surface roughness values of (Ra = 1.466, Rz = 9.428 m) and (Ra = 0.940, Rz = 7.963 m), respectively. For Ti6Al4V parts blasted with ZrO2 and then etched by HF, the wrought Ti6Al4V parts exhibited higher surface roughness (Ra = 1.631 µm, Rz = 10.953 µm) than the SLM Ti6Al4V parts (Ra = 1.336 µm, Rz = 10.353 µm) and the cast Ti6Al4V parts (Ra = 1.075 µm, Rz = 8.904 µm).
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113989
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 3990: Ballistic Impacts with Bullet
Splash—Load History Estimation for .308 Bullets vs. Hard Steel
Targets
Authors: Riccardo Andreotti, Andrea Casaroli, Ivan Colamartino, Mauro Quercia, Marco Virginio Boniardi, Filippo Berto
First page: 3990
Abstract: The study focuses on testing a simplified way of estimating the resultant force due to ballistic impacts resulting in a full fragmentation of the impactor with no penetration of the target. The method is intended to be useful for the parsimonious structural assessment of military aircrafts with integrated ballistic protection systems by means of large scale explicit finite element simulations. The research investigates the effectiveness of the method in allowing the prediction of the fields of plastic deformation collected by hard steel plates impacted by a wide range of semi-jacketed, monolithic, and full metal jacket .308 Winchester rifle bullets. The outcomes show the effectiveness of the method being strictly related to the full compliance of the considered cases with the bullet-splash hypotheses. The study therefore suggests the application of the load history approach only after careful experimental investigations on the specific impactor–target interactions.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113990
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 3991: Recent Advances in Processing of Titanium
and Titanium Alloys through Metal Injection Molding for Biomedical
Applications: 2013–2022
Authors: Al Basir, Norhamidi Muhamad, Abu Bakar Sulong, Nashrah Hani Jamadon, Farhana Mohd Foudzi
First page: 3991
Abstract: Metal injection molding (MIM) is one of the most widely used manufacturing processes worldwide as it is a cost-effective way of producing a variety of dental and orthopedic implants, surgical instruments, and other important biomedical products. Titanium (Ti) and Ti alloys are popular modern metallic materials that have revamped the biomedical sector as they have superior biocompatibility, excellent corrosion resistance, and high static and fatigue strength. This paper systematically reviews the MIM process parameters that extant studies have used to produce Ti and Ti alloy components between 2013 and 2022 for the medical industry. Moreover, the effect of sintering temperature on the mechanical properties of the MIM-processed sintered components has been reviewed and discussed. It is concluded that by appropriately selecting and implementing the processing parameters at different stages of the MIM process, defect-free Ti and Ti alloy-based biomedical components can be produced. Therefore, this present study could greatly benefit future studies that examine using MIM to develop products for biomedical applications.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113991
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 3992: A Rational Design of a CoS2-CoSe2
Heterostructure for the Catalytic Conversion of Polysulfides in
Lithium-Sulfur Batteries
Authors: Bin Zhang, Jiping Ma, Manman Cui, Yang Zhao, Shizhong Wei
First page: 3992
Abstract: Lithium-sulfur batteries are anticipated to be the next generation of energy storage devices because of their high theoretical specific capacity. However, the polysulfide shuttle effect of lithium-sulfur batteries restricts their commercial application. The fundamental reason for this is the sluggish reaction kinetics between polysulfide and lithium sulfide, which causes soluble polysulfide to dissolve into the electrolyte, leading to a shuttle effect and a difficult conversion reaction. Catalytic conversion is considered to be a promising strategy to alleviate the shuttle effect. In this paper, a CoS2-CoSe2 heterostructure with high conductivity and catalytic performance was prepared by in situ sulfurization of CoSe2 nanoribbon. By optimizing the coordination environment and electronic structure of Co, a highly efficient CoS2-CoSe2 catalyst was obtained, to promote the conversion of lithium polysulfides to lithium sulfide. By using the modified separator with CoS2-CoSe2 and graphene, the battery exhibited excellent rate and cycle performance. The capacity remained at 721 mAh g−1 after 350 cycles, at a current density of 0.5 C. This work provides an effective strategy to enhance the catalytic performance of two-dimensional transition-metal selenides by heterostructure engineering.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113992
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 3993: An Experimental Evaluation of Hemp as an
Internal Curing Agent in Concrete Materials
Authors: Rahnum T. Nazmul, Bre-Anne Sainsbury, Safat Al-Deen, Estela O. Garcez, Mahmud Ashraf
First page: 3993
Abstract: The construction industry is facing increased demand for adopting sustainable ‘green’ building materials to minimise the carbon footprint of the infrastructure sector to meet the United Nations 2030 Sustainability Goals. Natural bio-composite materials such as timber and bamboo have been widely used in construction for centuries. Hemp has also been used in different forms in the construction sector for decades for its thermal and acoustic insulation capability owing to its moisture buffering capacity and thermal conductivity. The current research aims to explore the possible application of hydrophilic hemp shives for assisting the internal curing of concrete materials as a biodegradable alternative to currently used chemical products. The properties of hemp have been assessed based on their water absorption and desorption properties associated with their characteristic sizes. It was observed that, in addition to its excellent moisture absorption capacity, hemp released most of its absorbed moisture into the surroundings under a high relative humidity (>93%); the best outcome was observed for smaller hemp particles (<2.36 mm). Furthermore, when compared to typical internal curing agents such as lightweight aggregates, hemp showed a similar behaviour in releasing its absorbed moisture to the surroundings indicating its potential application as a natural internal curing agent for concrete materials. An estimate of the volume of hemp shives required to provide a similar curing response to traditional internal curing techniques has been proposed.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113993
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 3994: Removal Performance of KOH-Modified
Biochar from Tropical Biomass on Tetracycline and Cr(VI)
Authors: Qingxiang Wang, Yan Yue, Wenfei Liu, Qing Liu, Yu Song, Chengjun Ge, Hongfang Ma
First page: 3994
Abstract: Biochar can be used to address the excessive use of tetracycline and micronutrient chromium (Cr) in wastewater that potentially threatens human health. However, there is little information about how the biochar, made from different tropical biomass, facilitates tetracycline and hexavalent chromium (Cr(VI)) removal from aqueous solution. In this study, biochar was prepared from cassava stalk, rubber wood and sugarcane bagasse, then further modified with KOH to remove tetracycline and Cr(VI). Results showed that pore characteristics and redox capacity of biochar were improved after modification. KOH-modified rubber wood biochar had the highest removal of tetracycline and Cr(VI), 1.85 times and 6 times higher than unmodified biochar. Tetracycline and Cr(VI) can be removed by electrostatic adsorption, reduction reaction, π–π stacking interaction, hydrogen bonding, pore filling effect and surface complexation. These observations will improve the understanding of the simultaneous removal of tetracycline and anionic heavy metals from wastewater.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113994
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 3995: Strength Investigation and Prediction of
Superfine Tailings Cemented Paste Backfill Based on Experiments and
Intelligent Methods
Authors: Yafei Hu, Keqing Li, Bo Zhang, Bin Han
First page: 3995
Abstract: The utilization of solid waste for filling mining presents substantial economic and environmental advantages, making it the primary focus of current filling mining technology development. To enhance the mechanical properties of superfine tailings cemented paste backfill (SCPB), this study conducted response surface methodology experiments to investigate the impact of various factors on the strength of SCPB, including the composite cementitious material, consisting of cement and slag powder, and the tailings’ grain size. Additionally, various microanalysis techniques were used to investigate the microstructure of SCPB and the development mechanisms of its hydration products. Furthermore, machine learning was utilized to predict the strength of SCPB under multi-factor effects. The findings reveal that the combined effect of slag powder dosage and slurry mass fraction has the most significant influence on strength, while the coupling effect of slurry mass fraction and underflow productivity has the lowest impact on strength. Moreover, SCPB with 20% slag powder has the highest amount of hydration products and the most complete structure. When compared to other commonly used prediction models, the long-short term memory neural network (LSTM) constructed in this study had the highest prediction accuracy for SCPB strength under multi-factor conditions, with root mean square error (RMSE), correlation coefficient (R), and variance account for (VAF) reaching 0.1396, 0.9131, and 81.8747, respectively. By optimizing the LSTM using the sparrow search algorithm (SSA), the RMSE, R, and VAF improved by 88.6%, 9.4%, and 21.9%, respectively. The research results can provide guidance for the efficient filling of superfine tailings.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113995
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 3996: Evaluation of the Effect of Binary Fly
Ash-Lime Mixture on the Bearing Capacity of Natural Soils: A Comparison
with Two Conventional Stabilizers Lime and Portland Cement
Authors: Yhan P. Arias-Jaramillo, Diana Gómez-Cano, Gloria I. Carvajal, César A. Hidalgo, Fredy Muñoz
First page: 3996
Abstract: This study evaluates a binary mixture of fly ash and lime as a stabilizer for natural soils. A comparative analysis was performed on the effect on the bearing capacity of silty, sandy and clayey soils after the addition of lime and ordinary Portland cement as conventional stabilizers, and a non-conventional product of a binary mixture of fly ash and Ca(OH)2 called FLM. Laboratory tests were carried out to evaluate the effect of additions on the bearing capacity of stabilized soils by unconfined compressive strength (UCS). In addition, a mineralogical analysis to validate the presence of cementitious phases due to chemical reactions with FLM was performed. The highest UCS values were found in the soils that required the highest water demand for compaction. Thus, the silty soil added with FLM reached 10 MPa after 28 days of curing, which was in agreement with the analysis of the FLM pastes, where soil moistures higher than 20% showed the best mechanical characteristics. Furthermore, a 120 m long track was built with stabilized soil to evaluate its structural behavior for 10 months. An increase of 200% in the resilient modulus of the FLM-stabilized soils was identified, and a decrease of up to 50% in the roughness index of the FLM, lime (L) and Ordinary Portland Cement (OPC)-stabilized soils compared to the soil without addition, resulting in more functional surfaces.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113996
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 3997: In Situ Synthesis of NiFeLDH/A–CBp
from Pyrolytic Carbon as High-Performance Oxygen Evolution Reaction
Catalyst for Water Splitting and Zinc Hydrometallurgy
Authors: Kai Che, Man Zhao, Yanzhi Sun, Junqing Pan
First page: 3997
Abstract: Nickel–iron-layered double hydroxide (NiFeLDH) is one of the promising catalysts for the oxygen evolution reaction (OER) in alkaline electrolytes, but its conductivity limits its large-scale application. The focus of current work is to explore low-cost, conductive substrates for large-scale production and combine them with NiFeLDH to improve its conductivity. In this work, purified and activated pyrolytic carbon black (CBp) is combined with NiFeLDH to form an NiFeLDH/A–CBp catalyst for OER. CBp not only improves the conductivity of the catalyst but also greatly reduces the size of NiFeLDH nanosheets to increase the activated surface area. In addition, ascorbic acid (AA) is introduced to enhance the coupling between NiFeLDH and A–CBp, which can be evidenced by the increase of Fe-O-Ni peak intensity in FTIR measurement. Thus, a lower overvoltage of 227 mV and larger active surface area of 43.26 mF·cm−2 are achieved in 1 M KOH solution for NiFeLDH/A–CBp. In addition, NiFeLDH/A–CBp shows good catalytic performance and stability as the anode catalyst for water splitting and Zn electrowinning in alkaline electrolytes. In Zn electrowinning with NiFeLDH/A–CBp, the low cell voltage of 2.08 V at 1000 A·m−2 results in lower energy consumption of 1.78 kW h/KgZn, which is nearly half of the 3.40 kW h/KgZn of industrial electrowinning. This work demonstrates the new application of high-value-added CBp in hydrogen production from electrolytic water and zinc hydrometallurgy to realize the recycling of waste carbon resources and reduce the consumption of fossil resources.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113997
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 3998: Near-Surface-Defect Detection in
Countersunk Head Riveted Joints Based on High-Frequency EMAT
Authors: Shuchang Zhang, Jiang Xu, Xin Yang, Hui Lin
First page: 3998
Abstract: Countersunk head riveted joints (CHRJs) are essential for the aerospace and marine industries. Due to the stress concentration, defects may be generated near the lower boundary of the countersunk head parts of CHRJs and require testing. In this paper, the near-surface defect in a CHRJ was detected based on high-frequency electromagnetic acoustic transducers (EMATs). The propagation of ultrasonic waves in the CHRJ with a defect was analyzed based on the theory of reflection and transmission. A finite element simulation was used to study the effect of the near-surface defect on the ultrasonic energy distribution in the CHRJ. The simulation results revealed that the second defect echo can be utilized for defect detection. The positive correlation between the reflection coefficient and the defect depth was obtained from the simulation results. To validate the relation, CHRJ samples with varying defect depths were tested using a 10-MHz EMAT. The experimental signals were denoised using wavelet-threshold denoising to improve the signal-to-noise ratio. The experimental results demonstrated a linearly positive correlation between the reflection coefficient and the defect depth. The results further showed that high-frequency EMATs can be employed for the detection of near-surface defects in CHRJs.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113998
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 3999: TSS Removal Efficiency and Permeability
Degradation of Sand Filters in Permeable Pavement
Authors: Phuong T.-H. Nguyen, Jongyeong Kim, Jaehun Ahn
First page: 3999
Abstract: Permeable pavement is a highly effective technology in Low-Impact Development (LID) for managing stormwater runoff, which helps mitigate environmental impacts. Filters are essential components of permeable pavement systems as they prevent permeability reduction, remove pollutants, and enhance the system’s overall efficiency. This research paper focuses on exploring the influence of three factors, including total suspended solids (TSS) particle size, TSS concentration, and hydraulic gradient, on the permeability degradation and TSS removal efficiency of sand filters. A series of tests were conducted using different values of these factors. The results demonstrate that these factors have an influence on permeability degradation and TSS removal efficiency (TRE). A larger TSS particle size results in higher permeability degradation and TRE than a smaller particle size. Higher TSS concentrations lead to higher permeability degradation and lower TRE. Additionally, smaller hydraulic gradients are associated with higher permeability degradation and TRE. However, the influence of TSS concentration and hydraulic gradient seems less significant than that of TSS particle size for the values of the factors considered in the tests. In summary, this study provides valuable insights into the effectiveness of sand filters in permeable pavement and identifies the main factors that influence permeability degradation and TRE.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16113999
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4000: Copper-Based Electrocatalysts for Nitrate
Reduction to Ammonia
Authors: Jia-Yi Fang, Jin-Long Fan, Sheng-Bo Liu, Sheng-Peng Sun, Yao-Yin Lou
First page: 4000
Abstract: Ammonia (NH3) is a highly important industrial chemical used as fuel and fertilizer. The industrial synthesis of NH3 relies heavily on the Haber–Bosch route, which accounts for roughly 1.2% of global annual CO2 emissions. As an alternative route, the electrosynthesis of NH3 from nitrate anion (NO3−) reduction (NO3−RR) has drawn increasing attention, since NO3−RR from wastewater to produce NH3 can not only recycle waste into treasure but also alleviate the adverse effects of excessive NO3− contamination in the environment. This review presents contemporary views on the state of the art in electrocatalytic NO3− reduction over Cu-based nanostructured materials, discusses the merits of electrocatalytic performance, and summarizes current advances in the exploration of this technology using different strategies for nanostructured-material modification. The electrocatalytic mechanism of nitrate reduction is also reviewed here, especially with regard to copper-based catalysts.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16114000
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4001: A Semi-Empirical Damage Model of Helankou
Rocks Based on Acoustic Emission
Authors: Youzhen Yang, Qingqing Lin, Hailong Ma, Jahanzaib Israr, Wei Liu, Yishen Zhao, Wenguo Ma, Gang Zhang, Hongbo Li
First page: 4001
Abstract: The Helankou rock as the relics carrier in Ningxia, China, have been suffering from serious weathering caused by variable environmental conditions. To study the freeze-thaw damage characteristics of Helankou relics carrier rocks, three dry-wet conditions (i.e., drying, pH = 2 and pH = 7) together with freeze-thaw experiments have been carried out at 0, 10, 20, 30, and 40 cycles. Additionally, a series of triaxial compression tests have been carried out at four different cell pressures of 4 MPa, 8 MPa, 16 MPa, and 32 MPa in tandem with a non-destructive acoustic emission technique. Subsequently, the rock damage variables were identified based on elastic modulus and acoustic emission ringing counts. It has been revealed that the acoustic emission positioning points reflected that the cracks would be concentrated near the surface of main fracture at higher cell pressures. Notably, the rock samples at 0 freeze-thaw cycles failed in pure shear. However, both shear slip and extension along the tensile cracks were observed at 20 freeze-thaw cycles, while tensile-oblique shear failure occurred at 40 freeze-thaw cycles. Not surprisingly, the decreasing order of deterioration inside the rock was observed to be (drying group) > (pH = 7 group) > (pH = 2 group). The peak values of damage variables in these three groups were also found to be consistent with the deterioration trend observed under freeze-thaw cycles. Finally, the semi-empirical damage model could rigorously ascertain stress and deformation behavior of rock samples, thus providing theoretical basis to establish a protection framework for Helankou relics.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16114001
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4002: Study of Hybrid Composite Joints with
Thin-Ply-Reinforced Adherends
Authors: Farin Ramezani, Ricardo J. C. Carbas, Eduardo A. S. Marques, Lucas F. M. da Silva
First page: 4002
Abstract: It has been demonstrated that a possible solution to reducing delamination in a unidirectional composite laminate lies in the replacement of conventional carbon-fibre-reinforced polymer layers with optimized thin-ply layers, thus creating hybrid laminates. This leads to an increase in the transverse tensile strength of the hybrid composite laminate. This study investigates the performance of a hybrid composite laminate reinforced by thin plies used as adherends in bonded single lap joints. Two different composites with the commercial references Texipreg HS 160 T700 and NTPT-TP415 were used as the conventional composite and thin-ply material, respectively. Three configurations were considered in this study: two reference single lap joints with a conventional composite or thin ply used as the adherends and a hybrid single lap. The joints were quasi-statically loaded and recorded with a high-speed camera, allowing for the determination of damage initiation sites. Numerical models of the joints were also created, allowing for a better understanding of the underlying failure mechanisms and the identification of the damage initiation sites. The results show a significant increase in tensile strength for the hybrid joints compared to the conventional ones as a result of changes in the damage initiation sites and the level of delamination present in the joint.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16114002
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4003: The Combined Effects of Hydraulic Calcium
Silicate Cement and Enamel Matrix Derivative Regarding Osteogenic and
Dentinogenic Differentiation on Human Dental Pulp Stem Cells
Authors: Ji-Young Yune, Donghee Lee, Sin-Young Kim
First page: 4003
Abstract: The ideal treatment option for immature necrotic permanent teeth is regeneration of the pulp–dentin complex. Mineral trioxide aggregate (MTA), the conventional cement used for regenerative endodontic procedures, induces hard tissue repair. Various hydraulic calcium silicate cements (HCSCs) and enamel matrix derivative (EMD) also promote osteoblast proliferation. The purpose of the present study was to determine the osteogenic and dentinogenic potential of commercially distributed MTA and HCSCs when applied in combination with Emdogain gel on human dental pulp stem cells (hDPSCs). The presence of Emdogain resulted in greater cell viability, and higher alkaline phosphatase activity was detected in the Emdogain-supplemented groups in the early days of cell culture. On qRT–PCR, the groups treated, respectively, with Biodentine and Endocem MTA Premixed in the presence of Emdogain showed an increased expression of the dentin formation marker DSPP, and the group treated with Endocem MTA Premixed in the presence of Emdogain showed an upregulated expression of the bone formation markers OSX and RUNX2. In an Alizarin Red-S staining assay, all of the experimental groups exhibited a greater formation of calcium nodules when treated in combination with Emdogain. Overall, the cytotoxicity and osteogenic/odontogenic potential of HCSCs were similar to that of ProRoot MTA. The addition of the EMD increased the osteogenic and dentinogenic differentiation markers.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16114003
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4004: Polyethylene Protective Coating with
Anti-Reflective Properties for Silicon Photovoltaic Cells
Authors: Malgorzata Pociask-Bialy
First page: 4004
Abstract: The aim of the study was to find the effect of polyethylene (PE) coatings on the short-circuit current of silicon photovoltaic cells covered with glass, in order to improve the short-circuit current of the cells. Various combinations of PE films (thicknesses ranging from 9 to 23 µm, number of layers ranging from two to six) with glasses (greenhouse, float, optiwhite and acrylic glass) were investigated. The best current gain of 4.05% was achieved for the coating combining a 1.5 mm thick acrylic glass with 2 × 12 µm thick PE films. This effect can be related to the formation of an array of micro-wrinkles and micrometer-sized air bubbles with a diameter of 50 to 600 µm in the films, which served as micro-lenses and enhanced light trapping.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16114004
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4005: Effects of Surface Properties of Fiber on
Interface Properties of Carbon Fiber/Epoxy Resin and Its Graphene Oxide
Modified Hybrid Composites
Authors: Weihua Bai, Wenjun Liu, Weidong Li, Zewen Lin, Hong Qiu, Xiaolan Hu
First page: 4005
Abstract: In the present study, surface properties of three types of carbon fibers (CCF300, CCM40J, and CCF800H) on the interface properties of carbon fiber/epoxy resin (CF/EP) were analyzed. The composites are further modified by graphene oxide (GO) to obtain GO/CF/EP hybrid composites. Meanwhile, the effect of the surface properties of CFs and the additive graphene oxide on the interlaminar shear properties and dynamic thermomechanical properties of GO/CF/EP hybrid composites are also analyzed. The results show that the higher surface oxygen-carbon ratio of carbon fiber (CCF300) has a positive effect on improving the glass transition temperature (Tg) of the CF/EP composites. The Tg of CCF300/EP is 184.4 °C, while the Tg of CCM40J/EP and CCF800/EP are only 177.1 °C and 177.4 °C, respectively. Furthermore, deeper and more dense grooves on the fiber surface (CCF800H and CCM40J) are more conducive to improving the interlaminar shear performance of the CF/EP composites. The interlaminar shear strength (ILSS) of CCF300/EP is 59.7 MPa, and that of CCM40J/EP and CCF800H/EP are 80.1 MPa and 83.5 MPa, respectively. For the GO/CF/EP hybrid composites, graphene oxide with abundant oxygen-containing groups is beneficial to improve the interfacial interaction. Graphene oxide can significantly improve the glass transition temperature and interlamellar shear strength of GO/CCF300/EP composites fabricated by CCF300 with a higher surface oxygen-carbon ratio. For the CCM40J and CCF800H with lower surface oxygen-carbon ratio, graphene oxide has a better modification effect on the glass transition temperature and interlamellar shear strength of GO/CCM40J/EP composites fabricated by CCM40J with deeper and finer surface grooves. Regardless of the type of carbon fiber, the GO/CF/EP hybrid composites with 0.1% graphene oxide have the optimized interlaminar shear strength, and the GO/CF/EP hybrid composites with 0.5% graphene oxide have the maximum glass transition temperature.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16114005
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4006: Stress Corrosion Cracking of 316L
Stainless Steel Additively Manufactured with Sinter-Based Material
Extrusion
Authors: Ricardo Santamaria, Ke Wang, Mobin Salasi, Mariano Iannuzzi, Michael Y. Mendoza, Md Zakaria Quadir
First page: 4006
Abstract: This study investigates the stress corrosion cracking (SCC) behavior of type 316L stainless steel (SS316L) produced with sinter-based material extrusion additive manufacturing (AM). Sinter-based material extrusion AM produces SS316L with microstructures and mechanical properties comparable to its wrought counterpart in the annealed condition. However, despite extensive research on SCC of SS316L, little is known about the SCC of sinter-based AM SS316L. This study focuses on the influence of sintered microstructures on SCC initiation and crack-branching susceptibility. Custom-made C-rings were exposed to different stress levels in acidic chloride solutions at various temperatures. Solution-annealed (SA) and cold-drawn (CD) wrought SS316L were also tested to understand the SCC behavior of SS316L better. Results showed that sinter-based AM SS316L was more susceptible to SCC initiation than SA wrought SS316L but more resistant than CD wrought SS316L, as determined by the crack initiation time. Sinter-based AM SS316L showed a noticeably lower tendency for crack-branching than both wrought SS316L counterparts. The investigation was supported by comprehensive pre- and post-test microanalysis using light optical microscopy, scanning electron microscopy, electron backscatter diffraction, and micro-computed tomography.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16114006
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4007: N-Doped Graphene-like Film/Silicon
Structures as Micro-Capacitor Electrodes
Authors: Daria M. Sedlovets
First page: 4007
Abstract: Currently, the miniaturization of portable and autonomous devices is challenging for modern electronics. Graphene-based materials have recently emerged as one of the ideal candidates for supercapacitor electrodes, while Si is a common platform for direct component-on-chip integration. We have proposed the direct liquid-based CVD of N-doped graphene-like films (N-GLFs) on Si as a promising way to achieve solid-state on-chip micro-capacitor performance. Synthesis temperatures in the range from 800 °C to 1000 °C are investigated. Capacitances and electrochemical stability of the films are evaluated using cyclic voltammetry, as well as galvanostatic measurements and electrochemical impedance spectroscopy in 0.5 M Na2SO4. We have shown that N-doping is an efficient way to improve the N-GLF capacitance. 900 °C is the optimal temperature for the N-GLF synthesis with the best electrochemical properties. The capacitance rises with increasing film thickness which also has an optimum (about 50 nm). The transfer-free acetonitrile-based CVD on Si yields a perfect material for microcapacitor electrodes. Our best value of the area-normalized capacitance (960 mF/cm2) exceeds the world’s achievements among thin graphene-based films. The main advantages of the proposed approach are the direct on-chip performance of the energy storage component and high cyclic stability.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16114007
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4008: Defect Dipole Behaviors on the Strain
Performances of Bismuth Sodium Titanate-Based Lead-Free Piezoceramics
Authors: Yiyi Wang, Pu Wang, Laijun Liu, Yuyin Wang, Yingying Zhao, Wenchao Tian, Xiao Liu, Fangyuan Zhu, Jing Shi
First page: 4008
Abstract: Bismuth sodium titanate (BNT)-based, lead-free piezoelectric materials have been extensively studied due to their excellent strain characteristics and environmental friendliness. In BNTs, the large strain (S) usually requires a relatively large electric field (E) excitation, resulting in a low inverse piezoelectric coefficient d33* (S/E). Moreover, the hysteresis and fatigue of strain in these materials have also been bottlenecks impeding the applications. The current common regulation method is chemical modification, which mainly focuses on forming a solid solution near the morphotropic phase boundary (MPB) by adjusting the phase transition temperature of the materials, such as BNT-BaTiO3, BNT-Bi0.5K0.5TiO3, etc., to obtain a large strain. Additionally, the strain regulation based on the defects introduced by the acceptor, donor, or equivalent dopant or the nonstoichiometry has proven effective, but its underlying mechanism is still ambiguous. In this paper, we review the generation of strain and then discuss it from the domain, volume, and boundary effect perspectives to understand the defect dipole behavior. The asymmetric effect caused by the coupling between defect dipole polarization and ferroelectric spontaneous polarization is expounded. Moreover, the defect effect on the conductive and fatigue properties of BNT-based solid solutions is described, which will affect the strain characteristics. The optimization approach is appropriately evaluated while there are still challenges in the full understanding of the defect dipoles and their strain output, in which further efforts are needed to achieve new breakthroughs in atomic-level insight.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16114008
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4009: Experimental Research on Surface Quality
of Titanium Rod Turned by Wire Electrical Discharge Turning Process
Authors: Sujeet Kumar Chaubey, Kapil Gupta
First page: 4009
Abstract: This paper reports the surface quality of a miniature cylindrical titanium rod/bar (MCTB) turned by the wire electrical discharge turning (WEDT) process using a zinc-coated wire of 250 µm diameter. The surface quality was mainly evaluated by considering the very important surface roughness parameters, i.e., the mean roughness depth. A Box–Behnken design (BBD) of the response surface methodology (RSM) based on 17 experimental runs was conducted, where the spark duration “Ton” was found as the most influential parameter affecting the mean roughness depth “RZ” of the miniature titanium bar. Further, using the grey relational analysis (GRA) technique of optimization, we obtained the least value of “RZ” 7.42 µm after machining a miniature cylindrical titanium bar with the optimum combination of WEDT’s variable parameters: Ton—0.9 µs, SV—30 V, and DOC—0.35 mm. This optimization led to a 37% reduction in the surface roughness Rz of the MCTB. The tribological characteristics of this MCTB were also found favorable after conducting a wear test. After completing a comparative study, we can claim that our results are better than those of the past research conducted in this area. The findings of this study are beneficial for the micro-turning of cylindrical bars made from a variety of difficult-to-machine materials.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16114009
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4010: UV-Activated Au Modified TiO2/In2O3 Hollow
Nanospheres for Formaldehyde Detection at Room Temperature
Authors: Su Zhang, Baoyu Huang, Zenghao Jiang, Junfan Qian, Jiawei Cao, Qiuxia Feng, Jianwei Zhang, Xiaogan Li
First page: 4010
Abstract: Au modified TiO2/In2O3 hollow nanospheres were synthesized by the hydrolysis method using the carbon nanospheres as a sacrificial template. Compared to pure In2O3, pure TiO2, and TiO2/In2O3 based sensors, the Au/TiO2/In2O3 nanosphere-based chemiresistive-type sensor exhibited excellent sensing performances to formaldehyde at room temperature under ultraviolet light (UV-LED) activation. The response of the Au/TiO2/In2O3 nanocomposite-based sensor to 1 ppm formaldehyde was about 5.6, which is higher than that of In2O3 (1.6), TiO2 (2.1), and TiO2/In2O3 (3.8). The response time and recovery time of the Au/TiO2/In2O3 nanocomposite sensor were 18 s and 42 s, respectively. The detectable formaldehyde concentration could go down as low as 60 ppb. In situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) was used to analyze the chemical reactions on the surface of the sensor activated by UV light. The improvement in the sensing properties of the Au/TiO2/In2O3 nanocomposites could be attributed to the nanoheterojunctions and electronic/chemical sensitization of the Au nanoparticles.
Citation: Materials
PubDate: 2023-05-26
DOI: 10.3390/ma16114010
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4011: The Impact of 3D Prism Cavity for Enhanced
Oil Recovery Using Different Nanomaterials
Authors: Mudasar Zafar, Hamzah Sakidin, Iskandar Dzulkarnain, Abida Hussain, Mikhail Sheremet, Roslinda Nazar, Abdullah Al-Yaari, Nur Asyatulmaila Mohamad Asri, Shazia Bashir
First page: 4011
Abstract: Enhanced oil recovery (EOR) has been offered as an alternative to declining crude oil production. EOR using nanotechnology is one of the most innovative trends in the petroleum industry. In order to determine the maximum oil recovery, the effect of a 3D rectangular prism shape is numerically investigated in this study. Using ANSYS Fluent software(2022R1), we develop a two-phase mathematical model based on 3D geometry. This research examines the following parameters: flow rate Q = 0.01–0.05 mL/min, volume fractions = 0.01–0.04%, and the effect of nanomaterials on relative permeability. The result of the model is verified with published studies. In this study, the finite volume method is used to simulate the problem, and we run simulations at different flow rates while keeping other variables constant. The findings show that the nanomaterials have an important effect on water and oil permeability, increasing oil mobility and lowering IFT, which increases the recovery process. Additionally, it has been noted that a reduction in the flow rate improves oil recovery. Maximum oil recovery was attained at a 0.05 mL/min flow rate. Based on the findings, it is also demonstrated that SiO2 provides better oil recovery compared to Al2O3. When the volume fraction concentration increases, oil recovery ultimately increases.
Citation: Materials
PubDate: 2023-05-27
DOI: 10.3390/ma16114011
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4012: Improved Yield and Electrical Properties
of Poly(Lactic Acid)/Carbon Nanotube Composites by Shear and Anneal
Authors: Dashan Mi, Zhongguo Zhao, Haiqing Bai
First page: 4012
Abstract: Shear and thermal processing can greatly influence nanoparticles’ orientation and dispersion, affecting the nanocomposites’ conductivity and mechanical properties. The synergistic effects of shear flow and Carbon nanotubes (CNTs) nucleating ability on the crystallization mechanisms have been proven. In this study, Polylactic acid/Carbon nanotubes (PLA/CNTs) nanocomposites were produced by three different molding methods: compression molding (CM), conventional injection molding (IM), and interval injection molding (IntM). Solid annealing at 80 °C for 4 h and pre-melt annealing at 120 °C for 3 h was applied to research the CNTs’ nucleation effect and the crystallized volume exclusion effect on the electrical conductivity and mechanical properties. The volume exclusion effect only significantly impacts the oriented CNTs, causing the conductivity along the transverse direction to rise by about seven orders of magnitude. In addition, the tensile modulus of the nanocomposites decreases with the increased crystallinity, while the tensile strength and modulus decrease.
Citation: Materials
PubDate: 2023-05-27
DOI: 10.3390/ma16114012
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4013: Hybrid Plasmas for Materials Processing
Authors: Kusano, Kusano
First page: 4013
Abstract: Hybrid plasmas have been reported in various areas of research over the last 40 years. However, a general overview of hybrid plasmas has never been presented or reported. In the present work, a survey of the literature and patents is carried out to provide the reader with a broad view of hybrid plasmas. The term refers to several different configurations of plasmas, including but not limited to: plasmas driven by several power sources simultaneously or sequentially, plasmas that have the properties of both thermal and nonthermal plasmas, plasmas that are enhanced by additional energy, and plasmas that are operated in a unique medium. In addition, a way of evaluating hybrid plasmas in terms of the improvement of processes is discussed, as well as the negative impacts that follow the employment of hybrid plasmas. Regardless of what the hybrid plasma in question is composed of, it often poses a unique advantage to its nonhybrid counterpart, whether it be used for welding, surface treatment, materials synthesis, coating deposition, gas phase reactions, or medicine.
Citation: Materials
PubDate: 2023-05-27
DOI: 10.3390/ma16114013
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4014: Influence of PBF-LB Process Atmosphere on
the Fatigue Strength of Hot Isostatically Post-Densified Duplex Steel
Parts Produced via the Shell Core Approach
Authors: Anke Kaletsch, Markus Sondermann, Markus Mirz, Felix Radtke, Christoph Broeckmann
First page: 4014
Abstract: Laser-based additive manufacturing is a great manufacturing technology for producing parts of any geometry. To also increase the strength and reliability of parts produced via powder bed fusion with laser beam (PBF-LB), hot isostatic pressing (HIP) is often used to densify residual porosity or lack-of-fusion defects. When components are post-densified via HIP, they do not require a high density beforehand, only a closed porosity or a dense shell. By building up samples with increased porosity, the PBF-LB process can be accelerated and productivity increased. HIP post-treatment gives the material its full density and good mechanical properties. However, with this approach, the influence of the process gases becomes important. Either argon or nitrogen is used in the PBF-LB process. It is assumed that these process gases are trapped in the pores and thus have an influence on the HIP process and also the mechanical properties after HIP. In this study, the influence of argon and nitrogen as process gases on the properties of duplex AISI 318LN steel after powder bed fusion with laser beam and hot isostatic pressing is investigated for the case of very high initial porosities.
Citation: Materials
PubDate: 2023-05-27
DOI: 10.3390/ma16114014
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4015: Interfacial Modification and Bending
Performance of 3D Orthogonal Woven Composites with Basalt Filament Yarns
Authors: Lihua Lyu, Fangfang Wen, Tingting Lyu, Xinghai Zhou, Yuan Gao
First page: 4015
Abstract: To improve their interfacial properties, 3D orthogonal woven fabrics with basalt filament yarns were modified with functionalized carboxylated carbon nanotubes (KH570-MWCNTs) and polydopamine (PDA). Fourier infrared spectroscopy (FT-IR) analysis and scanning electron microscopy (SEM) testing were used. It was demonstrated that both methods could successfully modify basalt fiber (BF) 3D woven fabrics. The 3D orthogonal woven composites (3DOWC) were produced with epoxy resin and 3D orthogonal woven fabrics as raw material by the VARTM molding process. The bending properties of the 3DOWC were tested and analyzed by experimental and finite element analysis methods. The results showed that the bending properties of the 3DOWC modified by KH570-MWCNTs and PDA were significantly improved, and the maximum bending loads were increased by 31.5% and 31.0%. The findings of the finite element simulation and the experiment results were in good agreement, and the simulation error value was 3.37%. The correctness of the finite element simulation results and the model’s validity further reveal the material’s damage situation and damage mechanism in the bending process.
Citation: Materials
PubDate: 2023-05-27
DOI: 10.3390/ma16114015
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4016: Three-Dimensional Flower-Like MoS2
Nanosheets Grown on Graphite as High-Performance Anode Materials for
Fast-Charging Lithium-Ion Batteries
Authors: Yeong A. Lee, Kyu Yeon Jang, Jaeseop Yoo, Kanghoon Yim, Wonzee Jung, Kyu-Nam Jung, Chung-Yul Yoo, Younghyun Cho, Jinhong Lee, Myung Hyun Ryu, Hyeyoung Shin, Kyubock Lee, Hana Yoon
First page: 4016
Abstract: The demand for fast-charging lithium-ion batteries (LIBs) with long cycle life is growing rapidly due to the increasing use of electric vehicles (EVs) and energy storage systems (ESSs). Meeting this demand requires the development of advanced anode materials with improved rate capabilities and cycling stability. Graphite is a widely used anode material for LIBs due to its stable cycling performance and high reversibility. However, the sluggish kinetics and lithium plating on the graphite anode during high-rate charging conditions hinder the development of fast-charging LIBs. In this work, we report on a facile hydrothermal method to achieve three-dimensional (3D) flower-like MoS2 nanosheets grown on the surface of graphite as anode materials with high capacity and high power for LIBs. The composite of artificial graphite decorated with varying amounts of MoS2 nanosheets, denoted as MoS2@AG composites, deliver excellent rate performance and cycling stability. The 20−MoS2@AG composite exhibits high reversible cycle stability (~463 mAh g−1 at 200 mA g−1 after 100 cycles), excellent rate capability, and a stable cycle life at the high current density of 1200 mA g−1 over 300 cycles. We demonstrate that the MoS2-nanosheets-decorated graphite composites synthesized via a simple method have significant potential for the development of fast-charging LIBs with improved rate capabilities and interfacial kinetics.
Citation: Materials
PubDate: 2023-05-27
DOI: 10.3390/ma16114016
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4017: Calcium Phosphate Cements as Carriers of
Functional Substances for the Treatment of Bone Tissue
Authors: Yulia Lukina, Tatiana Safronova, Dmitriiy Smolentsev, Otabek Toshev
First page: 4017
Abstract: Interest in calcium phosphate cements as materials for the restoration and treatment of bone tissue defects is still high. Despite commercialization and use in the clinic, the calcium phosphate cements have great potential for development. Existing approaches to the production of calcium phosphate cements as drugs are analyzed. A description of the pathogenesis of the main diseases of bone tissue (trauma, osteomyelitis, osteoporosis and tumor) and effective common treatment strategies are presented in the review. An analysis of the modern understanding of the complex action of the cement matrix and the additives and drugs distributed in it in relation to the successful treatment of bone defects is given. The mechanisms of biological action of functional substances determine the effectiveness of use in certain clinical cases. An important direction of using calcium phosphate cements as a carrier of functional substances is the volumetric incorporation of anti-inflammatory, antitumor, antiresorptive and osteogenic functional substances. The main functionalization requirement for carrier materials is prolonged elution. Various release factors related to the matrix, functional substances and elution conditions are considered in the work. It is shown that cements are a complex system. Changing one of the many initial parameters in a wide range changes the final characteristics of the matrix and, accordingly, the kinetics. The main approaches to the effective functionalization of calcium phosphate cements are considered in the review.
Citation: Materials
PubDate: 2023-05-27
DOI: 10.3390/ma16114017
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4018: Optical Properties of Carbon Dots
Synthesized by the Hydrothermal Method
Authors: Marfa Egorova, Aleksandra Tomskaya, Svetlana Afanasyevna Smagulova
First page: 4018
Abstract: In this study, the optical and structural properties of carbon dots (CDs) synthesized using a hydrothermal method were investigated. CDs were prepared from various precursors such as citric acid (CA), glucose, and birch bark soot. The SEM and AFM results show that the CDs are disc-shaped nanoparticles with dimensions of ~7 nm × 2 nm for CDs from CA, ~11 nm × 4 nm for CDs from glucose, and ~16 nm × 6 nm for CDs from soot. The TEM images of CDs from CA showed stripes with a distance of 0.34 nm between them. We assumed that the CDs synthesized from CA and glucose consisted of graphene nanoplates located perpendicular to the disc plane. The synthesized CDs contain oxygen (hydroxyl, carboxyl, carbonyl) and nitrogen (amino, nitro) functional groups. CDs have strong absorption in the ultraviolet region in the range of 200–300 nm. All CDs synthesized from different precursors displayed bright luminescence in the blue-green region of the spectrum (420–565 nm). We found that the luminescence of CDs depended on the synthesis time and type of precursors. The results show that the radiative transitions of electrons occur from two levels with energies ~3.0 eV and ~2.6 eV, which are due to the presence of functional groups.
Citation: Materials
PubDate: 2023-05-27
DOI: 10.3390/ma16114018
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4019: Properties of Accelerating Edge
Dislocations in Arbitrary Slip Systems with Reflection Symmetry
Authors: Daniel N. Blaschke, Khanh Dang, Saryu J. Fensin, Darby J. Luscher
First page: 4019
Abstract: We discuss the theoretical solution to the differential equations governing accelerating edge dislocations in anisotropic crystals. This is an important prerequisite to understanding high-speed dislocation motion, including an open question about the existence of transonic dislocation speeds, and subsequently high-rate plastic deformation in metals and other crystals.
Citation: Materials
PubDate: 2023-05-27
DOI: 10.3390/ma16114019
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4020: Effect of Near-Liquidus Squeeze Casting
Pressure on Microstructure and Mechanical Property of AZ91D Alloy
Differential Support
Authors: Chunfang Zhao, Guangquan Ma, Tong Liu, Maoliang Hu, Zesheng Ji
First page: 4020
Abstract: In this study, near-liquidus squeeze casting AZ91D alloy was used to prepare differential support, and the microstructure and mechanical behavior under different applied pressure were investigated. Under the preset temperature, speed, and other process parameters, the effect of applied pressure on the microstructure and properties of formed parts was analyzed, and relevant mechanism was also discussed. The results showed that the ultimate tensile strength (UTS) and elongation (EL) of differential support can be improved by controlling real-time precision of the forming pressure. The dislocation density in the primary phase increased obviously with the pressure increasing from 80 MPa to 170 MPa, and even tangles appeared. When the applied pressure increased from 80 MPa to 140 MPa, the α-Mg grains were gradually refined, and the microstructure changed from rosette to globular shape. With increasing the applied pressure to 170 MPa, the grain could not be further refined. Similarly, its UTS and EL gradually increased with the applied pressure increasing from 80 MPa to 140 MPa. With increasing to 170 MPa, the UTS tended to be constant, but the EL gradually decreased. In other words, the UTS (229.2 MPa) and EL (3.43%) of the alloy reached the maximum when the applied pressure was 140 MPa, and the comprehensive mechanical properties were the best.
Citation: Materials
PubDate: 2023-05-27
DOI: 10.3390/ma16114020
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4021: Ureido Hyperbranched Polymer Modified
Urea-Formaldehyde Resin as High-Performance Particleboard Adhesive
Authors: Hongxing Yang, Hao Wang, Guanben Du, Kelu Ni, Yingchen Wu, Hang Su, Wei Gao, Xiaoping Tan, Zhaojin Yang, Long Yang, Xin Ran
First page: 4021
Abstract: The performance of urea-formaldehyde (UF) resin and its formaldehyde emission is a natural contradiction. High molar ratio UF resin performance is very good, but its formaldehyde release is high; low molar ratio UF resin formaldehyde release is reduced, but the resin itself performance becomes very bad. In order to solve this traditional problem, an excellent strategy of UF resin modified by hyperbranched polyurea is proposed. In this work, hyperbranched polyurea (UPA6N) is first synthesized by a simple method without any solvent. UPA6N is then added into industrial UF resin in different proportions as additives to manufacture particleboard and test its related properties. UF resin with a low molar ratio has a crystalline lamellar structure, and UF-UPA6N resin has an amorphous structure and rough surface. The results show that internal bonding strength increased by 58.5%, modulus of rupture increased by 24.4%, 24 h thickness swelling rate (%) decreased by 54.4%, and formaldehyde emission decreased by 34.6% compared with the unmodified UF particleboard. This may be ascribed to the polycondensation between UF and UPA6N, while UF-UPA6N resin forms more dense three-dimensional network structures. Finally, the application of UF-UPA6N resin adhesives to bond particleboard significantly improves the adhesive strength and water resistance and reduces formaldehyde emission, suggesting that the adhesive can be used as a green and eco-friendly adhesive resource for the wood industry.
Citation: Materials
PubDate: 2023-05-27
DOI: 10.3390/ma16114021
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4022: Elemental Substitution at Tl Site of
Tl1−xXx(Ba, Sr)CaCu2O7 Superconductor with X = Cr, Bi, Pb, Se, and
Te
Authors: Jaafar Nur-Akasyah, Roslan Abd-Shukor, Tet Vui Chong
First page: 4022
Abstract: The effects of elemental substitutions at the Tl site of a Tl1−xXx(Ba, Sr)CaCu2O7 superconductor with X = Cr, Bi, Pb, Se, and Te were investigated. This study aimed to determine the elements that enhance and suppress the superconducting transition temperature of the Tl1−xXx(Ba, Sr)CaCu2O7 (Tl-1212) phase. The selected elements belong to the groups of transition metal, post-transition metal, non-metal, and metalloid. The relationship between the transition temperature and ionic radius of the elements was also discussed. The samples were prepared by the solid-state reaction method. The XRD patterns showed a single Tl-1212 phase was formed in the non- and Cr-substituted (x = 0.15) samples. The Cr-substituted samples (x = 0.4) showed a plate-like structure with smaller voids. The highest superconducting transition temperatures (Tc onset, Tcχ′, and Tp) were also achieved by the Cr-substituted samples for x = 0.4 compositions. However, the substitution of Te suppressed the superconductivity of the Tl-1212 phase. Jc inter (Tp) for all samples was calculated to be in the range of 12–17 A/cm2. This work shows that substitution elements with a smaller ionic radius tend to be more favorable in improving the superconducting properties of the Tl-1212 phase.
Citation: Materials
PubDate: 2023-05-27
DOI: 10.3390/ma16114022
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4023: Investigation of the Friction Properties
of a New Artificial Imitation Cartilage Material: PHEMA/Glycerol Gel
Authors: Zikai Hua, Mindie Hu, Yiwen Chen, Xiuling Huang, Leiming Gao
First page: 4023
Abstract: The absence of artificial articular cartilage could cause the failure of artificial joints due to excessive material wear. There has been limited research on alternative materials for articular cartilage in joint prostheses, with few reducing the friction coefficient of artificial cartilage prostheses to the range of the natural cartilage friction coefficient (0.001–0.03). This work aimed to obtain and characterize mechanically and tribologically a new gel for potential application in articular replacement. Therefore, poly(hydroxyethyl methacrylate) (PHEMA)/glycerol synthetic gel was developed as a new type of artificial joint cartilage with a low friction coefficient, especially in calf serum. This glycerol material was developed via mixing HEMA and glycerin at a mass ratio of 1:1. The mechanical properties were studied, and it was found that the hardness of the synthetic gel was close to that of natural cartilage. The tribological performance of the synthetic gel was investigated using a reciprocating ball-on-plate rig. The ball samples were made of a cobalt-chromium-molybdenum (Co-Cr-Mo) alloy, and the plates were synthetic glycerol gel and two additional materials for comparison, which were ultra-high molecular polyethylene (UHMWPE) and 316L stainless steel. It was found that synthetic gel exhibited the lowest friction coefficient in both calf serum (0.018) and deionized water (0.039) compared to the other two conventional materials for knee prostheses. The surface roughness of the gel was found to be 4–5 μm through morphological analysis of wear. This newly proposed material provided a possible solution as a type of cartilage composite coating with hardness and tribological performance close to the nature of use in wear couples with artificial joints.
Citation: Materials
PubDate: 2023-05-28
DOI: 10.3390/ma16114023
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4024: Experimental and Numerical Simulation on
the Penetration for Basic Magnesium Sulfate Cement Concrete
Authors: Qiquan Mei, Hongfa Yu, Haiyan Ma, Yongshan Tan, Zhangyu Wu
First page: 4024
Abstract: The penetration resistance of the new material Basic Magnesium Sulfate Cement (BMSC) is studied through comprehensive application of an experimental and numerical simulation method. This paper consists of three parts. The first part introduces the preparation of Basic Magnesium Sulfate Cement Concrete (BMSCC) and the study of its dynamic mechanical properties. In the second part, on-site testing was carried out on both BMSCC and an ordinary Portland cement concrete (OPCC) target, and the anti-penetration performance of the two materials was analyzed and compared from three aspects: penetration depth, crater diameter and volume, and failure mode. In the last part, the numerical simulation analysis was carried out based on LS-DYNA, and the effects of factors, such as material strength and penetration velocity on the penetration depth, are analyzed. According to the results, the BMSCC targets have better penetration resistance performance than OPCC under the same conditions, mainly manifested in smaller penetration depth, smaller crater diameter and volume, as well as fewer cracks.
Citation: Materials
PubDate: 2023-05-28
DOI: 10.3390/ma16114024
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4025: Study on Dynamic and Static Mechanical
Properties of Copper-Plated Steel-Fiber-Reinforced Self-Compacting
Concrete
Authors: Juan Qi, Aonan Liu, Peng Su, Chaomin Mu
First page: 4025
Abstract: The mechanical properties and impact resistance of conventional self-compacting concrete (SCC) need to be further improved. In order to explore the dynamic and static mechanical properties of copper-plated steel-fiber-reinforced self-compacting concrete (CPSFRSCC), the static mechanical properties and dynamic mechanical properties of CPSFRSCC with a different volume fraction of copper-plated steel fiber (CPSF) are tested, and a numerical experiment is carried out to analyze the experimental results. The results show that the mechanical properties of self-compacting concrete (SCC) can be effectively improved by adding CPSF, especially for the tensile mechanical properties. The static tensile strength of CPSFRSCC shows a trend that increases with the increase in the volume fraction of CPSF and then reaches the maximum when the volume fraction of CPSF is 3%. The dynamic tensile strength of CPSFRSCC shows a trend that increases first and then decrease with the increase in the volume fraction of CPSF, and then reaches the maximum when the volume fraction of CPSF is 2%. The results of the numerical simulation show that the failure morphology of CPSFRSCC is closely related to the content of CPSF; with the increase in the volume fraction of CPSF, the fracture morphology of the specimen gradually evolves from complete fracture to incomplete fracture.
Citation: Materials
PubDate: 2023-05-28
DOI: 10.3390/ma16114025
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4026: Unveiling the Effects of Quicklime on the
Properties of Sulfoaluminate Cement–Ordinary Portland
Cement–Mineral Admixture Repairing Composites and Their Sulphate
Resistance
Authors: Chen Shi, Ying Yang
First page: 4026
Abstract: Aiming at the problem of repeated repair of concrete caused by the damage of concrete structure repair system in a sulphate environment, the quicklime modified sulphoaluminate cement (CSA)–ordinary Portland cement (OPC) –mineral admixture composite repair material was utilised to obtain the law and mechanism of quicklime, improving the mechanical properties and sulphate resistance of composite repair materials. In this paper, the effects of quicklime on the mechanical properties, as well as sulphate resistance of CSA–OPC–ground granulated blast furnace slag (SPB) and CSA–OPC–silica fume (SPF) composites, were studied. The findings reveal that the addition of quicklime improves the stability of ettringite in SPB and SPF composite systems, promotes the pozzolanic reaction of mineral admixtures in composite systems, and significantly increases the compressive strength of both SPB and SPF systems. The 8 h compressive strength of SPB and SPF composite systems increased by 154% and 107%, and the 28 d compressive strength enhanced by 32% and 40%. After the quicklime was added, the formation of C-S-H gel and calcium carbonate in SPB and SPF composite systems was promoted, the porosity was reduced, and the pore structure was refined. The porosity was reduced by 2.68% and 0.48%, respectively. The mass change rate of various composite systems under sulphate attack was reduced, and the mass change rate of the SPCB30 and SPCF9 composite systems decreased to 0.11% and −0.76% after 150 dry–wet cycles. Additionally, the mechanical strength of different composite systems under sulphate attack was improved, so that the sulphate resistance of different ground granulated blast furnace slag and silica fume composite systems was improved.
Citation: Materials
PubDate: 2023-05-28
DOI: 10.3390/ma16114026
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4027: Synthesis and Improved Photoluminescence
Authors: Jisheng Xu, Haixia Wu, Xinye Lu, Yaqian Huang, Jianni Chen, Wendi Zhou, Zewen Lin, Jie Song, Hongliang Li, Rui Huang
First page: 4027
Abstract: We report a rapid synthesis method for producing CsSnCl3:Mn2+ perovskites, derived from SnF2, and investigate the effects of rapid thermal treatment on their photoluminescence properties. Our study shows that the initial CsSnCl3:Mn2+ samples exhibit a double luminescence peak structure with PL peaks at approximately 450 nm and 640 nm, respectively. These peaks originate from defect-related luminescent centers and the 4T1→6A1 transition of Mn2+. However, as a result of rapid thermal treatment, the blue emission is significantly reduced and the red emission intensity is increased nearly twofold compared to the pristine sample. Furthermore, the Mn2+-doped samples demonstrate excellent thermal stability after the rapid thermal treatment. We suggest that this improvement in photoluminescence results from enhanced excited-state density, energy transfer between defects and the Mn2+ state, as well as the reduction of nonradiative recombination centers. Our findings provide valuable insights into the luminescence dynamics of Mn2+-doped CsSnCl3 and open up new possibilities for controlling and optimizing the emission of rare-earth-doped CsSnCl3.
Citation: Materials
PubDate: 2023-05-28
DOI: 10.3390/ma16114027
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4028: Ceramic Thermal Insulator Based on
Diatomite Obtained by Starch Consolidation Casting
Authors: Cinthya Alvarado, Hernán Alvarado-Quintana, Raúl Siche
First page: 4028
Abstract: Researchers are continuously seeking to develop new materials to protect against inclement weather and thus optimize energy efficiency in housing. This research aimed to determine the influence of corn starch percentage on the physicomechanical and microstructural properties of a diatomite-based porous ceramic. The starch consolidation casting technique was applied to fabricate a diatomite-based thermal insulating ceramic with hierarchical porosity. Diatomite mixtures with 0%, 10%, 20%, 30%, and 40% starch were consolidated. The results show that starch content significantly influences apparent porosity, and this, in turn, influences several parameters, such as thermal conductivity, diametral compressive strength, microstructure, and water absorption of diatomite-based ceramics. The porous ceramic processed by the starch consolidation casting method corresponding to the mixture of diatomite with 30% starch obtained the best properties, with a thermal conductivity of 0.0984 W/m·K, an apparent porosity of 57.88%, a water absorption of 58.45%, and a diametral compressive strength of 35.18 kg/cm2 (3.45 MPa). Our results reveal that the diatomite-based ceramic thermal insulator obtained by starch consolidation is effective for use on roofs to improve thermal comfort in dwellings located in cold regions.
Citation: Materials
PubDate: 2023-05-28
DOI: 10.3390/ma16114028
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4029: Sol-Gel Synthesis and Photoluminescence
Properties of a Far-Red Emitting Phosphor BaLaMgTaO6:Mn4+ for Plant Growth
LEDs
Authors: Niansi Fan, Quan Du, Rui Guo, Lan Luo, Li Wang
First page: 4029
Abstract: Far-red (FR) emitting LEDs are known as a promising supplement light source for photo-morphogenesis of plants, in which FR emitting phosphors are indispensable components. However, mostly reported FR emitting phosphors are suffering from problems of wavelength mismatch with LED chips or low quantum efficiency, which are still far from practical applications. Here, a new efficient FR emitting double-perovskite phosphor BaLaMgTaO6:Mn4+ (BLMT:Mn4+) has been prepared by sol-gel method. The crystal structure, morphology and photoluminescence properties have been investigated in detail. BLMT:Mn4+ phosphor has two strong and wide excitation bands in the range of 250–600 nm, which matches well with a near-UV or blue chip. Under 365 nm or 460 nm excitation, BLMT:Mn4+ emits an intense FR light ranging from 650 to 780 nm with maximum emission at 704 nm due to 2Eg → 4A2g forbidden transition of Mn4+ ion. The critical quenching concentration of Mn4+ in BLMT is 0.6 mol%, and its corresponding internal quantum efficiency is as high as 61%. Moreover, BLMT:Mn4+ phosphor has good thermal stability, with emission intensity at 423 K keeping 40% of the room temperature value. The LED devices fabricated with BLMT:Mn4+ sample exhibit bright FR emission, which greatly overlaps with the absorption curve of FR absorbing phytochrome, indicating that BLMT:Mn4+ is a promising FR emitting phosphor for plant growth LEDs.
Citation: Materials
PubDate: 2023-05-28
DOI: 10.3390/ma16114029
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4030: Preparation and Photocatalytic Performance
of MoS2/MoO2 Composite Catalyst
Authors: Daoyu Dong, Weitao Yan, Yaqiu Tao, Yunfei Liu, Yinong Lu, Zhigang Pan
First page: 4030
Abstract: Solar energy is an inexhaustible clean energy providing a key solution to the dual challenges of energy and environmental crises. Graphite-like layered molybdenum disulfide (MoS2) is a promising photocatalytic material with three different crystal structures, 1T, 2H and 3R, each with distinct photoelectric properties. In this paper, 1T-MoS2 and 2H-MoS2, which are widely used in photocatalytic hydrogen evolution, were combined with MoO2 to form composite catalysts using a bottom-up one-step hydrothermal method. The microstructure and morphology of the composite catalysts were studied by XRD, SEM, BET, XPS and EIS. The prepared catalysts were used in the photocatalytic hydrogen evolution of formic acid. The results show that MoS2/MoO2 composite catalysts have an excellent catalytic effect on hydrogen evolution from formic acid. By analyzing the photocatalytic hydrogen production performance of composite catalysts, it suggests that the properties of MoS2 composite catalysts with different polymorphs are distinct, and different content of MoO2 also bring differences. Among the composite catalysts, 2H-MoS2/MoO2 composite catalysts with 48% MoO2 content show the best performance. The hydrogen yield is 960 µmol/h, which is 1.2 times pure 2H-MoS2 and two times pure MoO2. The hydrogen selectivity reaches 75%, which is 22% times higher than that of pure 2H-MoS2 and 30% higher than that of MoO2. The excellent performance of the 2H-MoS2/MoO2 composite catalyst is mainly due to the formation of the heterogeneous structure between MoS2 and MoO2, which improves the migration of photogenerated carriers and reduces the possibilities of recombination through the internal electric field. MoS2/MoO2 composite catalyst provides a cheap and efficient solution for photocatalytic hydrogen production from formic acid.
Citation: Materials
PubDate: 2023-05-28
DOI: 10.3390/ma16114030
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4031: Study of the Mechanisms of Radiation
Softening and Swelling upon Irradiation of TiTaNbV Alloys with He2+ Ions
with an Energy of 40 keV
Authors: Sholpan G. Giniyatova, Kayrat K. Kadyrzhanov, Dmitriy I. Shlimas, Daryn B. Borgekov, Vladimir V. Uglov, Artem L. Kozlovskiy, Maxim V. Zdorovets
First page: 4031
Abstract: This paper presents simulation results of the ionization losses of incident He2+ ions with an energy of 40 keV during the passage of incident ions in the near-surface layer of alloys based on TiTaNbV with a variation of alloy components. For comparison, data on the ionization losses of incident He2+ ions in pure niobium, followed by the addition of vanadium, tantalum, and titanium to the alloy in equal stoichiometric proportions, are presented. With the use of indentation methods, the dependences of the change in the strength properties of the near-surface layer of alloys were determined. It was established that the addition of Ti to the composition of the alloy leads to an increase in resistance to crack resistance under high-dose irradiation, as well as a decrease in the degree of swelling of the near-surface layer. During tests on the thermal stability of irradiated samples, it was found that swelling and degradation of the near-surface layer of pure niobium affects the rate of oxidation and subsequent degradation, while for high-entropy alloys, an increase in the number of alloy components leads to an increase in resistance to destruction.
Citation: Materials
PubDate: 2023-05-28
DOI: 10.3390/ma16114031
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4032: Effect of Curing Conditions on the
Hydration of MgO in Cement Paste Mixed with MgO Expansive Agent
Authors: Xuefeng Zhao, Zhongyang Mao, Xiaojun Huang, Penghui Luo, Min Deng, Mingshu Tang
First page: 4032
Abstract: Using the volume expansion generated by the hydration of the MgO expansive agent to compensate for the shrinkage deformation of concrete is considered to be an effective measure to prevent concrete shrinkage and cracking. Existing studies have mainly focused on the effect of the MgO expansive agent on the deformation of concrete under constant temperature conditions, but mass concrete in practical engineering experiences a temperature change process. Obviously, the experience obtained under constant temperature conditions makes it difficult to accurately guide the selection of the MgO expansive agent under actual engineering conditions. Based on the C50 concrete project, this paper mainly investigates the effect of curing conditions on the hydration of MgO in cement paste under actual variable temperature conditions by simulating the actual temperature change course of C50 concrete so as to provide a reference for the selection of the MgO expansive agent in engineering practice. The results show that temperature was the main factor affecting the hydration of MgO under variable temperature curing conditions, and the increase in the temperature could obviously promote the hydration of MgO in cement paste, while the change in the curing methods and cementitious system had an effect on the hydration of MgO, though this effect was not obvious.
Citation: Materials
PubDate: 2023-05-28
DOI: 10.3390/ma16114032
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4033: Experimental Study of the Factors
Influencing the Regeneration Performance of Reduced Graphite Oxide Filter
Materials under Water Cleaning
Authors: Min Yang, Bing Yang, Xin Zhang, Saisai Wu, Tao Yu, Hong Song, Fei Ren, Puchun He, Yanhui Zhu
First page: 4033
Abstract: With the normalization of epidemic prevention and control, air filters are being used and replaced more frequently. How to efficiently utilize air filter materials and determining whether they have regenerative properties have become current research hotspots. This paper discusses the regeneration performance of reduced graphite oxide filter materials, which were studied in depth using water cleaning and the relevant parameters, including the cleaning times. The results showed that water cleaning was most effective using a 20 L/(s·m2) water flow velocity with a 17 s cleaning time. The filtration efficiency decreased as the number of cleanings increased. Compared to the blank group, the filter material’s PM10 filtration efficiency decreased by 0.8%, 19.4%, 26.5%, and 32.4% after the first to fourth cleanings, respectively. The filter material’s PM2.5 filtration efficiency increased by 12.5% after the first cleaning, and decreased by 12.9%, 17.6%, and 30.2% after the second to fourth cleanings, respectively. The filter material’s PM1.0 filtration efficiency increased by 22.7% after the first cleaning, and decreased by 8.1%, 13.8%, and 24.5% after the second to fourth cleanings, respectively. Water cleaning mainly affected the filtration efficiency of particulates sized 0.3–2.5 μm. Reduced graphite oxide air filter materials could be water washed twice and maintain cleanliness equal to 90% of the original filter material. Water washing more than twice could not achieve the standard cleanliness equal to 85% of the original filter material. These data provide useful reference values for the evaluation of the filter materials’ regeneration performance.
Citation: Materials
PubDate: 2023-05-28
DOI: 10.3390/ma16114033
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4034: Metaheuristic Optimization of Random
Forest for Predicting Punch Shear Strength of FRP-Reinforced Concrete
Beams
Authors: Peixi Yang, Chuanqi Li, Yingui Qiu, Shuai Huang, Jian Zhou
First page: 4034
Abstract: Predicting the punching shear strength (PSS) of fiber-reinforced polymer reinforced concrete (FRP-RC) beams is a critical task in the design and assessment of reinforced concrete structures. This study utilized three meta-heuristic optimization algorithms, namely ant lion optimizer (ALO), moth flame optimizer (MFO), and salp swarm algorithm (SSA), to select the optimal hyperparameters of the random forest (RF) model for predicting the punching shear strength (PSS) of FRP-RC beams. Seven features of FRP-RC beams were considered as inputs parameters, including types of column section (TCS), cross-sectional area of the column (CAC), slab’s effective depth (SED), span–depth ratio (SDR), compressive strength of concrete (CSC), yield strength of reinforcement (YSR), and reinforcement ratio (RR). The results indicate that the ALO-RF model with a population size of 100 has the best prediction performance among all models, with MAE of 25.0525, MAPE of 6.5696, R2 of 0.9820, and RMSE of 59.9677 in the training phase, and MAE of 52.5601, MAPE of 15.5083, R2 of 0.941, and RMSE of 101.6494 in the testing phase. The slab’s effective depth (SED) has the largest contribution to predicting the PSS, which means that adjusting SED can effectively control the PSS. Furthermore, the hybrid machine learning model optimized by metaheuristic algorithms outperforms traditional models in terms of prediction accuracy and error control.
Citation: Materials
PubDate: 2023-05-28
DOI: 10.3390/ma16114034
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4035: Study on Physical Properties of
Desulfurized Electrolytic Manganese Residue Cement and Properties of
Mortar
Authors: Shichao Chen, Fang Wang, Lihua Ma, Jialing Che
First page: 4035
Abstract: The desulfurized electrolytic manganese residue (DMR) was prepared by calcination and desulfurization of industrial waste electrolytic manganese residue, and the original DMR was ground to prepare DMR fine powder (GDMR) with specific surface areas of 383 m2/kg, 428 m2/kg, and 629 m2/kg. The effects of particle fineness and content of GDMR (GDMR content=0%, 10%, 20%, 30%) on the physical properties of cement and the mechanical properties of mortar were studied. After that, the leachability of heavy metal ions was tested, and the hydration products of GDMR cement were analyzed using XRD and SEM. The results show that the addition of GDMR can regulate the fluidity and water requirement for the normal consistency of cement, delay the hydration process of cement, increase the initial setting and final setting time of cement, and reduce the strength of cement mortar, especially the strength of early age mortar. As the fineness of GDMR increases, the reduction of bending strength and compressive strength decreases, and the activity index increases. The content of GDMR has a significant effect on short-term strength. With the increase in GDMR content, the strength reduction degree becomes higher and the activity index decreases. When the content of GDMR was 30%, the 3D compressive strength and bending strength decreased by 33.1% and 29%. When the content of GDMR in cement is less than 20%, the maximum limit of leachable heavy metal content in cement clinker can be met.
Citation: Materials
PubDate: 2023-05-28
DOI: 10.3390/ma16114035
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4036: Effects of Maleic Anhydride-Grafted
Polyethylene on the Properties of Artificial Marble Waste Powder/Linear
Low-Density Polyethylene Composites with Ultra-High Filling Content
Authors: Juncheng Die, Jianting Ma, Hai Li, Yafeng Zhang, Fei Li, Yang Cao, Wanjun Hao, Jinchun Tu, Kexi Zhang, Rentong Yu
First page: 4036
Abstract: The need to reach carbon neutrality as soon as possible has made the use of recycled materials widespread. However, the treatment of artificial marble waste powder (AMWP) containing unsaturated polyester is a very challenging task. This task can be accomplished by converting AMWP into new plastic composites. Such conversion is a cost-effective and eco-friendly way to recycle industrial waste. However, the lack of mechanical strength in composites and the low filling content of AMWP have been major obstacles to its practical application in structural and technical buildings. In this study, a composite of AMWP/linear low-density polyethylene (LLDPE) filled with a 70 wt% AMWP content was fabricated using maleic anhydride-grafted polyethylene as a compatibilizer (MAPE). The mechanical strength of the prepared composites is excellent (tensile strength ~18.45 MPa, impact strength ~51.6 kJ/m2), making them appropriate as useful building materials. Additionally, laser particle size analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermogravimetric analysis were used to examine the effects of maleic anhydride-grafted polyethylene on the mechanical properties of AMWP/LLDPE composites and its mechanism of action. Overall, this study offers a practical method for the low-cost recycling of industrial waste into high-performance composites.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114036
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4037: Protective Performance of Coated
Reinforcement in Coral Concrete under Dry/Wet Cycling
Authors: Hongji Cao, Qing Wu, Muhammad Akbar, Ning Yang, Zahoor Hussain
First page: 4037
Abstract: The actual protective performance of the coated reinforcement in coral concrete was investigated by measuring the chloride ion diffusion coefficient, electrochemical analysis, and numerical simulation. The test results show that the corrosion rate of coated reinforcement in coral concrete under the action of wet and dry cycles is kept at a low level, and the Rp value is always greater than 250 kΩ·cm2 during the test period, which is in the uncorroded state and has good protection performance. Moreover, the chloride ion diffusion coefficient D is in accordance with the power function relationship with the wet and dry cycle time, and a time-varying model of chloride ion concentration on the surface of coral concrete is established. The surface chloride ion concentration of coral concrete reinforcement was modeled as a time-varying model; the cathodic zone of coral concrete members was the most active, increasing from 0 V to 0.14 V from 0 to 20 years, with a large increase in potential difference before the 7th year, and a significant decrease in the increase after the 7th year.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114037
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4038: Use of a Waste-Derived Linde Type-A
Immobilized in Agarose for the Remediation of Water Impacted by Coal Acid
Mine Drainage at Pilot Scale
Authors: Cristiano Luiz Chostak, Aurora López-Delgado, Isabel Padilla, Flávio Rubens Lapolli, María Ángeles Lobo-Recio
First page: 4038
Abstract: A new adsorbent based on an immobilized waste-derived LTA zeolite in agarose (AG) has proven to be an innovative and efficient alternative for removing metallic contaminants from water impacted by acid mine drainage (AMD) because the immobilization prevents the solubilization of the zeolite in acidic media and eases its separation from the adsorbed solution. A pilot device was developed containing slices of the sorbent material [AG (1.5%)–LTA (8%)] to be used in a treatment system under an upward continuous flow. High removals of Fe2+ (93.45%), Mn2+ (91.62%), and Al3+ (96.56%) were achieved, thus transforming river water heavily contaminated by metallic ions into water suitable for non-potable use for these parameters, according to Brazilian and/or FAO standards. Breakthrough curves were constructed and the corresponding maximum adsorption capacities (mg/g) (Fe2+, 17.42; Mn2+, 1.38; Al3+, 15.20) calculated from them. Thomas mathematical model was well fitted to the experimental data, indicating the participation of an ion-exchange mechanism in the removal of the metallic ions. The pilot-scale process studied, in addition to being highly efficient in removing metal ions at toxic levels in AMD-impacted water, is linked to the sustainability and circular economy concepts, due to the use as an adsorbent of a synthetic zeolite derived from a hazardous aluminum waste.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114038
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4039: Composition Design and Tensile Properties
of Additive Manufactured Low Density Hf-Nb-Ta-Ti-Zr High Entropy Alloys
Based on Atomic Simulations
Authors: Zhuoheng Liang, Yiming Wu, Yu Miao, Wei Pan, Yongzhong Zhang
First page: 4039
Abstract: High-entropy alloy (HEA) is a new type of multi-principal alloy material and the Hf-Nb-Ta-Ti-Zr HEAs have attracted more and more attention from researchers due to their high melting point, special plasticity, and excellent corrosion resistance. In this paper, in order to reduce the density of the alloy and maintain the strength of the Hf-Nb-Ta-Ti-Zr HEAs, the effects of high-density elements Hf and Ta on the properties of HEAs were explored for the first time based on molecular dynamics simulations. A low-density and high-strength Hf0.25NbTa0.25TiZr HEA suitable for laser melting deposition was designed and formed. Studies have shown that the decrease in the proportion of Ta element reduces the strength of HEA, while the decrease in Hf element increases the strength of HEA. The simultaneous decrease in the ratio of Hf and Ta elements reduces the elastic modulus and strength of HEA and leads to the coarsening of the alloy microstructure. The application of laser melting deposition (LMD) technology refines the grains and effectively solves the coarsening problem. Compared with the as-cast state, the as-deposited Hf0.25NbTa0.25TiZr HEA obtained by LMD forming has obvious grain refinement (from 300 μm to 20–80 μm). At the same time, compared with the as-cast Hf0.25NbTa0.25TiZr HEA (σs = 730 ± 23 MPa), the as-deposited Hf0.25NbTa0.25TiZr HEA has higher strength (σs = 925 ± 9 MPa), which is similar to the as-cast equiatomic ratio HfNbTaTiZr HEA (σs = 970 ± 15 MPa).
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114039
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4040: Influence of Isocyanate Structure on
Recyclable Shape Memory Poly(thiourethane)
Authors: Yu Zeng, Jiale Song, Jinfu Li, Chi Yuan
First page: 4040
Abstract: In this study, poly(thiourethane) (PTU) with different structures is synthesized by click chemistry from trimethylolpropane tris(3-mercaptopropionate) (S3) and different diisocyanates (hexamethylene diisocyanate, HDI, isophorone diisocyanate, IPDI and toluene diisocyanate, TDI). Quantitative analysis of the FTIR spectra reveals that the reaction rates between TDI and S3 are the most rapid, resulting from the combined influence of conjugation and spatial site hindrance. Moreover, the homogeneous cross-linked network of the synthesized PTUs facilitates better manageability of the shape memory effect. All three PTUs exhibit excellent shape memory properties (Rr and Rf are over 90%), and an increase in chain rigidity is observed to negatively impact the shape recovery rate and fix rate. Moreover, all three PTUs exhibit satisfactory reprocessability performance, and an increase in chain rigidity is accompanied by a greater decrease in shape memory and a smaller decrease in mechanical performance for recycled PTUs. Contact angle (<90°) and in vitro degradation results (13%/month for HDI-based PTU, 7.5%/month for IPDI-based PTU, and 8.5%/month for TDI-based PTU) indicate that PTUs can be used as long-term or medium-term biodegradable materials. The synthesized PTUs have a high potential for applications in smart response scenarios requiring specific glass transition temperatures, such as artificial muscles, soft robots, and sensors.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114040
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4041: Electronic Structures of Penta-SiC2 and
g-SiC3 Nanoribbons: A First-Principles Study
Authors: Zhichao Liu, Xiaobiao Liu, Junru Wang
First page: 4041
Abstract: The dimensions of nanoribbons have a significant impact on their material properties. In the fields of optoelectronics and spintronics, one-dimensional nanoribbons exhibit distinct advantages due to their low-dimensional and quantum restrictions. Novel structures can be formed by combining silicon and carbon at different stoichiometric ratios. Using density functional theory, we thoroughly explored the electronic structure properties of two kinds of silicon–carbon nanoribbons (penta-SiC2 and g-SiC3 nanoribbons) with different widths and edge conditions. Our study reveals that the electronic properties of penta-SiC2 and g-SiC3 nanoribbons are closely related to their width and orientation. Specifically, one type of penta-SiC2 nanoribbons exhibits antiferromagnetic semiconductor characteristics, two types of penta-SiC2 nanoribbons have moderate band gaps, and the band gap of armchair g-SiC3 nanoribbons oscillates in three dimensions with the width of the nanoribbon. Notably, zigzag g-SiC3 nanoribbons exhibit excellent conductivity, high theoretical capacity (1421 mA h g−1), moderate open circuit voltage (0.27 V), and low diffusion barriers (0.09 eV), making them a promising candidate for high storage capacity electrode material in lithium-ion batteries. Our analysis provides a theoretical basis for exploring the potential of these nanoribbons in electronic and optoelectronic devices as well as high-performance batteries.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114041
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4042: Study on the Stability of Low-Carbon
Magnesium Cementitious Materials in Sulfate Erosion Environments
Authors: Yuan Jia, Xinmei Zou, Yaoting Jiang, Yuxin Zou, Shuanglin Song, Jianyun Qin, Yongjing Wang, Lihua Zhu
First page: 4042
Abstract: The current investigation focuses on the stability of the magnesium oxide-based cementitious system under the action of sulfate attack and the dry-wet cycle. The phase change in the magnesium oxide-based cementitious system was quantitatively analyzed by X-ray diffraction, combined with thermogravimetry/derivative thermogravimetry and scanning electron microscope, to explore its erosion behavior under an erosion environment. The results revealed that, in the fully reactive magnesium oxide-based cementitious system under the environment of high concentration sulfate erosion, there was only magnesium silicate hydrate gel formation and no other phase; however, the reaction process of the incomplete magnesium oxide-based cementitious system was delayed, but not inhibited, by the environment of high-concentration sulfate, and it tended to turn completely into a magnesium silicate hydrate gel. The magnesium silicate hydrate sample outperformed the cement sample, in terms of stability in a high-concentration sulfate erosion environment, but it tended to degrade considerably more rapidly, and to a greater extent, than Portland cement, in both dry and wet sulfate cycle environments.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114042
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4043: Modification of Concrete Composition Doped
by Sewage Sludge Fly Ash and Its Effect on Compressive Strength
Authors: Tomasz Kalak, Patrycja Szypura, Ryszard Cierpiszewski, Małgorzata Ulewicz
First page: 4043
Abstract: The sustainable development of construction materials is an essential aspect of current worldwide trends. Reusing post-production waste in the building industry has numerous positive effects on the environment. Since concrete is one of the materials that people manufacture and use the most, it will continue to be an integral element of the surrounding reality. In this study, the relationship between the individual components and parameters of concrete and its compressive strength properties was assessed. In the experimental works, concrete mixes with different contents of sand, gravel, Portland cement CEM II/B-S 42.5 N, water, superplasticizer, air-entraining admixture, and fly ash from the thermal conversion of municipal sewage sludge (SSFA) were designed. According to legal requirements in the European Union, SSFA waste from the sewage sludge incineration process in a fluidized bed furnace should not be stored in landfills but processed in various ways. Unfortunately, its generated amounts are too large, so new management technologies should be sought. During the experimental work, the compressive strength of concrete samples of various classes, namely, C8/10, C12/15, C16/20, C20/25, C25/30, C30/37, and C35/45, were measured. The higher-class concrete samples that were used, the greater the compressive strength obtained, ranging from 13.7 to 55.2 MPa. A correlation analysis was carried out between the mechanical strength of waste-modified concretes and the composition of concrete mixes (the amount of sand and gravel, cement, and FA), as well as the water-to-cement ratio and the sand point. No negative effect of the addition of SSFA on the strength of concrete samples was demonstrated, which translates into economic and environmental benefits.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114043
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4044: Yttrium and Niobium Elements Co-Doping and
the Formation of Double Perovskite Structure Ba2YNbO6 in BCZT
Authors: Runyu Mao, Deyi Zheng, Qiyun Wu, Yuying Wang, Chang Liu
First page: 4044
Abstract: The (Ba0.85Ca0.15) (Ti0.90Zr0.10)O3 + x Y3+ + x Nb5+ (abbreviated as BCZT-x(Nb + Y), x = 0 mol%, 0.05 mol%, 0.1 mol%, 0.2 mol%, 0.3 mol%) lead-free piezoceramics samples were prepared by a traditional solid-state sintering method. And the effects of Yttrium and Niobium elements (Y3+ and Nb5+) co-doping on the defect, phase and structure, microstructure, and comprehensive electrical properties have been investigated. Research results show that the Y and Nb elements co-doping can dramatically enhance piezoelectric properties. It is worth noting that XPS defect chemistry analysis, XRD phase analysis and TEM results together show that a new phase of double perovskite structure Barium Yttrium Niobium Oxide (Ba2YNbO6) is formed in the ceramic, and the XRD Rietveld refinement and TEM results show the coexistence of the R-O-T phase. Both these two reasons together lead to significant performance improvements of piezoelectric constant (d33) and planar electro-mechanical coupling coefficient (kp). The functional relation between temperature and dielectric constant testing results present that the Curie temperature increases slightly, which shows the same law as the change of piezoelectric properties. The ceramic sample reaches an optimal performance at x = 0.1% of BCZT-x(Nb + Y), where d33 = 667 pC/N, kp = 0.58, εr = 5656, tanδ = 0.022, Pr = 12.8 μC/cm2, EC = 2.17 kV/cm, TC =92 °C, respectively. Therefore, they can be used as potential alternative materials to lead based piezoelectric ceramics.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114044
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4045: Influence of Carbonated Bottom Slag
Granules in 3D Concrete Printing
Authors: Karolina Butkute, Vitoldas Vaitkevicius, Maris Sinka, Algirdas Augonis, Aleksandrs Korjakins
First page: 4045
Abstract: This study investigates the possibility of utilising bottom slag (BS) waste from landfills, and a carbonation process advantageous for the use of artificial aggregates (AAs) in printed three-dimensional (3D) concrete composites. In general, the main idea of granulated aggregates is to reduce the amount of CO2 emissions of printed 3D concrete objects (wall). AAs are made from construction materials, both granulated and carbonated. Granules are made from a combination of binder (ordinary Portland cement (OPC), hydrated lime, burnt shale ash (BSA)) and waste material (BS). BS is a waste material left over after the municipal waste burning process in cogeneration power plants. Whole printed 3D concrete composite manufacturing consists of: granulating artificial aggregate, aggregate hardening and sieving (adaptive granulometer), carbonation of AA, mixing 3D concrete, and 3D printing. The granulating and printing processes were analysed for hardening processes, strength results, workability parameters, and physical and mechanical properties. Printings with no granules (reference 3D printed concrete) were compared to 3D printed concretes with 25% and 50% of their natural aggregate replaced with carbonated AA. The results showed that, theoretically, the carbonation process could help to react approximately 126 kg/m3 CO2 from 1 m3 of granules.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114045
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4046: Study on Local-Structure Symmetrization of
K2XF6 Crystals Doped with Mn4+ Ions by First-Principles Calculations
Authors: Mega Novita, Sigit Ristanto, Ernawati Saptaningrum, Slamet Supriyadi, Dian Marlina, Ferdy Semuel Rondonuwu, Alok Singh Chauhan, Benjamin Walker, Kazuyoshi Ogasawara, Michal Piasecki, Mikhail G. Brik
First page: 4046
Abstract: The crystals of Mn4+-activated fluorides, such as those of the hexafluorometallate family, are widely known for their luminescence properties. The most commonly reported red phosphors are A2XF6: Mn4+ and BXF6: Mn4+ fluorides, where A represents alkali metal ions such as Li, Na, K, Rb, Cs; X=Ti, Si, Ge, Zr, Sn, B = Ba and Zn; and X = Si, Ge, Zr, Sn, and Ti. Their performance is heavily influenced by the local structure around dopant ions. Many well-known research organizations have focused their attention on this area in recent years. However, there has been no report on the effect of local structural symmetrization on the luminescence properties of red phosphors. The purpose of this research was to investigate the effect of local structural symmetrization on the polytypes of K2XF6 crystals, namely Oh-K2MnF6, C3v-K2MnF6, Oh-K2SiF6, C3v-K2SiF6, D3d-K2GeF6, and C3v-K2GeF6. These crystal formations yielded seven-atom model clusters. Discrete Variational Xα (DV-Xα) and Discrete Variational Multi Electron (DVME) were the first principles methods used to compute the Molecular orbital energies, multiplet energy levels, and Coulomb integrals of these compounds. The multiplet energies of Mn4+ doped K2XF6 crystals were qualitatively reproduced by taking lattice relaxation, Configuration Dependent Correction (CDC), and Correlation Correction (CC) into account. The 4A2g→4T2g (4F) and 4A2g→4T1g (4F) energies increased when the Mn-F bond length decreased, but the 2Eg → 4A2g energy decreased. Because of the low symmetry, the magnitude of the Coulomb integral became smaller. As a result, the decreasing trend in the R-line energy could be attributed to a decreased electron–electron repulsion.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114046
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4047: Microstructure and Mechanical Properties
of Weaving Wire and Arc Additive Manufactured AZ91 Magnesium Alloy Based
on Cold Metal Transfer Technique
Authors: Zhongrui Zhang, Junqi Shen, Ji Bi, Shengsun Hu, Yahui Zhen, Xianzheng Bu
First page: 4047
Abstract: Based on the cold metal transfer (CMT) technique, a deposited wall of AZ91 magnesium alloy was fabricated by weaving wire and arc additive manufacturing (WAAM), the shaping, microstructure, and mechanical properties of the sample with the weaving arc were characterized and discussed by compared with the sample without the weaving arc, and the effects of the weaving arc on grain refinement and property enhancement of the AZ91 component by CMT-WAAM process were investigated. After introducing the weaving arc, the effective rate of the deposited wall could be increased from 84.2% to 91.0%, and the temperature gradient of the molten pool could be reduced with an increase in constitutional undercooling. The equiaxed α-Mg grains became more equiaxial due to the dendrite remelting, and the β-Mg17Al12 phases distributed uniformly induced by the forced convection after introducing the weaving arc. Compared to the deposited component fabricated by the CMT-WAAM process without the weaving arc, the average ultimate tensile strength and elongation of the component by weaving the CMT-WAAM process both increased. The weaving CMT-WAAM component showed isotropy and has better performance than the traditional cast AZ91 alloy.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114047
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4048: Manufacture and Vibration-Damping Effect
of Composites for Archery Carbon Fiber-Reinforced Polymer Limb with Glass
Fiber-Reinforced Polymer Stabilizer
Authors: Won Wook Heo, Seung Kook An, Jeong Hyun Yeum, Seong Baek Yang, Sejin Choi
First page: 4048
Abstract: Typically, archers prepare two sets of bows for competitions in case of bow breakage, but if the limbs of the bow break during a match, archers can become psychologically disadvantaged, leading to potentially fatal consequences. Archers are very sensitive to the durability and vibration of their bows. While the vibration-damping properties of Bakelite® stabilizer are excellent, its low density and somewhat lower strength and durability are disadvantages. As a solution, we used carbon fiber-reinforced plastic (CFRP) and glass fiber-reinforced plastic (GFRP) for the archery limb with stabilizer, commonly used for the limbs of the bow, to manufacture the limb. The stabilizer was reverse-engineered from the Bakelite® product and manufactured using glass fiber-reinforced plastic in the same shape as the existing product. Analyzing the vibration-damping effect and researching ways to reduce the vibration that occurs during shooting through 3D modeling and simulation, it was possible to evaluate the characteristics and the effect of reducing the limb’s vibration by manufacturing archery bows and limbs using carbon fiber- and glass fiber-reinforced composites. The objective of this study was to manufacture archery bows using CFRP and GFRP, and to assess their characteristics as well as their effectiveness at reducing limb vibration. Through testing, the limb and stabilizer that were produced were determined to not fall behind the abilities of the bows currently used by athletes, and they also exhibited a noticeable reduction in vibrations.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114048
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4049: The Application of a Fluoride-and-Vitamin
D Solution to Deciduous Teeth Promotes Formation of Persistent Mineral
Crystals: A Morphological Ex-Vivo Study
Authors: Gianni Di Giorgio, Michela Relucenti, Flavia Iaculli, Alessandro Salucci, Orlando Donfrancesco, Antonella Polimeni, Maurizio Bossù
First page: 4049
Abstract: Background: The use of effective, low-cost, and easy-to-use products for early caries management will avoid loss of dental vitality and impairment in oral function. The ability of fluoride to re-mineralize dental surfaces has been widely reported as well as vitamin D demonstrated to have significant potential in improving the remineralization of early lesions on enamel surfaces. The aim of the present ex vivo study was to evaluate the effect of a fluoride and vitamin D solution in terms of formation of mineral crystals on the enamel of primary teeth, and their permanence over time on dental surfaces. Methods: Sixteen extracted deciduous teeth were cut to obtain 64 specimens that were divided into two groups. The first consisted of immersion of specimens for 4 days in a fluoride solution (T1); in the second group, the specimens were immersed for 4 days (T1) in fluoride and Vitamin D solution, and for a further 2 (T2) and 4 days (T3) in saline solution. Then, samples were morphologically analyzed by using Variable Pressure Scanning Electron Microscope (VPSEM) and underwent 3D surface reconstruction. Results: After a 4-day immersion in both solutions, octahedral-shaped crystals were formed on the enamel surface of primary teeth, demonstrating any statistically significant differences in terms of number, size, and shape. Moreover, the binding of the same crystals seemed to be strong enough to be maintained until 4 days in saline solution. However, a partial dissolution was observed in a time-dependent manner. Conclusions: A topical application of fluoride and Vitamin D promoted the formation of persistent mineral crystals on enamel surfaces of deciduous teeth and should be further studied to be potentially used as an alternative strategy in preventive dentistry.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114049
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4050: A Modified Bond-Associated Non-Ordinary
State-Based Peridynamic Model for Impact Problems of Quasi-Brittle
Materials
Authors: Jing Zhang, Yaxun Liu, Xin Lai, Lisheng Liu, Hai Mei, Xiang Liu
First page: 4050
Abstract: In this work, we have developed a novel bond-associated non-ordinary state-based peridynamic (BA-NOSB PD) model for the numerical modeling and prediction of the impact response and fracture damage of quasi-brittle materials. First, the improved Johnson-Holmquist (JH2) constitutive relationship is implemented in the framework of BA-NOSB PD theory to describe the nonlinear material response, which also helps to eliminate the zero-energy mode. Afterwards, the volumetric strain in the equation of state is redefined by the introduction of the bond-associated deformation gradient, which can effectively improve the stability and accuracy of the material model. Then, a new general bond-breaking criterion is proposed in the BA-NOSB PD model, which is capable of covering various failure modes of quasi-brittle materials, including the tensile-shear failure that is not commonly considered in the literature. Subsequently, a practical bond-breaking strategy and its computational implementation are presented and discussed by means of energy convergence. Finally, the proposed model is verified by two benchmark numerical examples and demonstrated by the numerical simulation of edge-on impact and normal impact experiments on ceramics. The comparison between our results and references shows good capability and stability for impact problems of quasi-brittle materials. Numerical oscillations and unphysical deformation modes are effectively eliminated, showing strong robustness and bright prospects for relevant applications.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114050
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4051: [2.2]Paracyclophane Derivatives as
Building Blocks for Coordination Polymers
Authors: Mihail Lucian Birsa, Henning Hopf, Peter G. Jones, Laura Gabriela Sarbu, Lucian Gabriel Bahrin
First page: 4051
Abstract: Several new di- and tetracarboxylic [2.2]paracyclophane derivatives were obtained via Suzuki coupling between the appropriately brominated [2.2]paracyclophanes and 4-(methoxycarbonyl)phenylboronic acid. The reaction of one of these products, namely pp-bis(4-carboxyphenyl)[2.2]paracylophane (12), with zinc nitrate afforded a 2D coordination polymer comprising zinc-carboxylate paddlewheel clusters linked together by cyclophane cores. The zinc center is five-coordinated in a square-pyramidal geometry, with a DMF oxygen atom at the apex and four carboxylate oxygen atoms in the base.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114051
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4052: A Review of Natural Fiber-Based Filaments
for 3D Printing: Filament Fabrication and Characterization
Authors: Mohd Nazri Ahmad, Mohamad Ridzwan Ishak, Mastura Mohammad Taha, Faizal Mustapha, Zulkiflle Leman
First page: 4052
Abstract: Today, additive manufacturing (AM) is the most recent technology used to produce detailed and complexly built parts for a variety of applications. The most emphasis has been given to fused deposition modeling (FDM) in the development and manufacturing fields. Natural fibers have received attention in the area of 3D printing to be employed as bio-filters with thermoplastics, which have prompted an effort for more ecologically acceptable methods of manufacturing. The development of natural fiber composite filaments for FDM requires meticulous methods and in-depth knowledge of the properties of natural fibers and their matrices. Thus, this paper reviews natural fiber-based 3D printing filaments. It covers the fabrication method and characterization of thermoplastic materials blended with natural fiber-produced wire filament. The characterization of wire filament includes the mechanical properties, dimension stability, morphological study, and surface quality. There is also a discussion of the difficulties in developing a natural fiber composite filament. Last but not least, the prospects of natural fiber-based filaments for FDM 3D printing are also discussed. It is hoped that, after reading this article, readers will have enough knowledge regarding how natural fiber composite filament for FDM is created.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114052
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4053: Highly Efficient ITO-Free Quantum-Dot
Light Emitting Diodes via Solution-Processed PEDOT:PSS Semitransparent
Electrode
Authors: Jin Hyun Ma, Min Gye Kim, Jun Hyung Jeong, Min Ho Park, Hyoun Ji Ha, Seong Jae Kang, Seong Jun Kang
First page: 4053
Abstract: We present a study on the potential use of sulfuric acid-treated poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a viable alternative to indium tin oxide (ITO) electrodes in quantum dot light-emitting diodes (QLEDs). ITO, despite its high conductivity and transparency, is known for its disadvantages of being brittle, fragile, and expensive. Furthermore, due to the high hole injection barrier of quantum dots, the need for electrodes with a higher work function is becoming more significant. In this report, we present solution-processed, sulfuric acid-treated PEDOT:PSS electrodes for highly efficient QLEDs. The high work function of the PEDOT:PSS electrodes improved the performance of the QLEDs by facilitating hole injection. We demonstrated the recrystallization and conductivity enhancement of PEDOT:PSS upon sulfuric acid treatment using X-ray photoelectron spectroscopy and Hall measurement. Ultraviolet photoelectron spectroscopy (UPS) analysis of QLEDs showed that sulfuric acid-treated PEDOT:PSS exhibited a higher work function than ITO. The maximum current efficiency and external quantum efficiency based on the PEDOT:PSS electrode QLEDs were measured as 46.53 cd/A and 11.01%, which were three times greater than ITO electrode QLEDs. These findings suggest that PEDOT:PSS can serve as a promising replacement for ITO electrodes in the development of ITO-free QLED devices.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114053
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4054: Heat Treatment Optimization for a High
Authors: Hongyu Liu, Hao Zhang, Liju Meng, Yulong Li, Sheng Cao
First page: 4054
Abstract: A selective laser-melted Al–Mn–Sc alloy with 99.9% relative density has been obtained in this work through systematic process optimization. The as-fabricated specimen had the lowest hardness and strength, but the highest ductility. The aging response has shown that 300 °C/5 h is the peak aged condition, and it had the highest hardness, yield strength, ultimate tensile strength, and elongation at fracture. Such a high strength was attributed to the uniformly distributed nano-sized secondary Al3Sc precipitates. A further increase in aging temperature to 400 °C resulted in an over-aged condition, which contained a reduced volume fraction of secondary Al3Sc precipitates and resulted in a reduced strength.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114054
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4055: Accelerated Direct Carbonation of Steel
Slag and Cement Kiln Dust: An Industrial Symbiosis Strategy Applied in the
Bergamo–Brescia Area
Authors: Giada Biava, Annalisa Zacco, Alessandra Zanoletti, Giampiero Pasquale Sorrentino, Claudia Capone, Antonio Princigallo, Laura Eleonora Depero, Elza Bontempi
First page: 4055
Abstract: The carbonation of alkaline industrial wastes is a pressing issue that is aimed at reducing CO2 emissions while promoting a circular economy. In this study, we explored the direct aqueous carbonation of steel slag and cement kiln dust in a newly developed pressurized reactor that operated at 15 bar. The goal was to identify the optimal reaction conditions and the most promising by-products that can be reused in their carbonated form, particularly in the construction industry. We proposed a novel, synergistic strategy for managing industrial waste and reducing the use of virgin raw materials among industries located in Lombardy, Italy, specifically Bergamo–Brescia. Our initial findings are highly promising, with argon oxygen decarburization (AOD) slag and black slag (sample 3) producing the best results (70 g CO2/kg slag and 76 g CO2/kg slag, respectively) compared with the other samples. Cement kiln dust (CKD) yielded 48 g CO2/kg CKD. We showed that the high concentration of CaO in the waste facilitated carbonation, while the presence of Fe compounds in large amounts caused the material to be less soluble in water, affecting the homogeneity of the slurry.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114055
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4056: Enhancement of the Desorption Properties
of LiAlH4 by the Addition of LaCoO3
Authors: Noratiqah Sazelee, Nurul Amirah Ali, Mohammad Ismail, Sami-Ullah Rather, Hisham S. Bamufleh, Hesham Alhumade, Aqeel Ahmad Taimoor, Usman Saeed
First page: 4056
Abstract: The high hydrogen storage capacity (10.5 wt.%) and release of hydrogen at a moderate temperature make LiAlH4 an appealing material for hydrogen storage. However, LiAlH4 suffers from slow kinetics and irreversibility. Hence, LaCoO3 was selected as an additive to defeat the slow kinetics problems of LiAlH4. For the irreversibility part, it still required high pressure to absorb hydrogen. Thus, this study focused on the reduction of the onset desorption temperature and the quickening of the desorption kinetics of LiAlH4. Here, we report the different weight percentages of LaCoO3 mixed with LiAlH4 using the ball-milling method. Interestingly, the addition of 10 wt.% of LaCoO3 resulted in a decrease in the desorption temperature to 70 °C for the first stage and 156 °C for the second stage. In addition, at 90 °C, LiAlH4 + 10 wt.% LaCoO3 can desorb 3.37 wt.% of H2 in 80 min, which is 10 times faster than the unsubstituted samples. The activation energies values for this composite are greatly reduced to 71 kJ/mol for the first stages and 95 kJ/mol for the second stages compared to milled LiAlH4 (107 kJ/mol and 120 kJ/mol for the first two stages, respectively). The enhancement of hydrogen desorption kinetics of LiAlH4 is attributed to the in situ formation of AlCo and La or La-containing species in the presence of LaCoO3, which resulted in a reduction of the onset desorption temperature and activation energies of LiAlH4.
Citation: Materials
PubDate: 2023-05-29
DOI: 10.3390/ma16114056
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4057: Preparation, Characterization, and
Chemically Modified Date Palm Fiber Waste Biomass for Enhanced Phenol
Removal from an Aqueous Environment
Authors: Nadavala Siva Kumar, Mohammad Asif, Anesh Manjaly Poulose, Ebrahim H. Al-Ghurabi, Shaddad S. Alhamedi, Janardhan Reddy Koduru
First page: 4057
Abstract: The date palm tree is extensively cultivated in Middle Eastern countries such as Saudi Arabia, generating a large amount of waste in the form of leaves, seeds, and fibrous materials. This study examined the feasibility of using raw date palm fiber (RDPF) and NaOH chemically modified date palm fiber (NaOH–CMDPF) obtained from discarded agricultural waste for the removal of phenol in an aqueous environment. The adsorbent characterization was performed by using different techniques, i.e., particle size analysis; elemental analyzer (CHN); and BET, FTIR, and FESEM-EDX analysis. The FTIR analysis revealed the presence of various functional groups on the surface of the RDPF and NaOH–CMDPF. The results showed that chemical modification by NaOH increased the phenol adsorption capacity that was well-fitted by the Langmuir isotherm. Higher removal was obtained with NaOH–CMDPF (86%) than with the RDPF (81%). The RDPF and NaOH–CMDPF sorbents’ maximum (Qm) adsorption capacities were more than 45.62 mg/g and 89.67 mg/g and were comparable to the sorption capacities of various other types of agricultural waste biomass reported in the literature. The kinetic studies confirmed that the adsorption of phenol followed the pseudo-second-order kinetic process. The present study concluded that the RDPF and NaOH–CMDPF were eco-friendly and cost-effective in promoting sustainable management and the reuse of the Kingdom’s lignocellulosic fiber waste material.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114057
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4058: Biogenic Fabrication of Silver
Nanoparticles Using Calotropis procera Flower Extract with Enhanced
Biomimetics Attributes
Authors: Pooja V. Nagime, Sudarshan Singh, Nishat M. Shaikh, Komal S. Gomare, Havagiray Chitme, Basel A. Abdel-Wahab, Yahya S. Alqahtany, Masood Medleri Khateeb, Mohammed Shafiuddin Habeeb, Marwa B. Bakir
First page: 4058
Abstract: There have been some reports demonstrating the biogenic synthesis of silver nanoparticles (AgNPs) using Calotropis procera (CP) plant extract; however, detailed in-depth debriefing of the vital synthesis parameter for rapid, facile, efficacious synthesis at varied temperatures with effectual characterization of nanoparticles and biomimetic attribute is lacking. This study presents a comprehensive demarcation of the sustainable fabrication of biogenic C. procera flower extract capped and stabilized silver nanoparticles (CP-AgNPs) synthesis with thorough phytochemical characterization and potential biological application. The results revealed that the successful synthesis of CP-AgNPs was instantaneous with the maximum intensity of the plasmonic peak ~400 nm, while morphological results revealed the cubic shape of nanoparticles. CP-AgNPs were found to present stable, well-dispersed, uniform, high anionic zeta potential, and crystalline nanoparticles with a crystallite size of ~23.8 nm. The FTIR spectra indicated that CP-AgNPs were properly capped by the bioactive of C. procera. Moreover, the synthesized CP-AgNPs exhibited hydrogen peroxide scavenging efficacy. In addition, CP-AgNPs showed antibacterial and antifungal activity against pathogenic bacteria. CP-AgNPs displayed significant in vitro antidiabetic and anti-inflammatory activity. An efficient and convenient approach for synthesizing AgNPs using C. procera flower has been developed with enhanced biomimetic attributes that may be further utilized for water treatment, biosensors, biomedicine, and in allied science.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114058
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4059: Investigation of Microstructure and
Authors: Yaxin Gao, Xilei Bian, Xingbao Qiu, Yandong Jia, Jun Yi, Gang Wang
First page: 4059
Abstract: Low Ag lead-free Sn-Ag-Cu (SAC) solders have attracted great interest due to their good drop resistance, high welding reliability, and low melting point. However, low Ag may lead to the degradation of the mechanical properties. Micro-alloying is an effective approach to improving the properties of SAC alloys. In this paper, the effects of minor additions of Sb, In, Ni, and Bi on microstructure, thermal and mechanical properties of Sn-1 wt.%Ag-0.5 wt.%Cu (SAC105) were systematically investigated. It is found that the microstructure can be refined with intermetallic compounds (IMCs) distributed more evenly in the Sn matrix with additions of Sb, In, and Ni, which brings a combined strengthening mechanism, i.e., solid solution strengthening and precipitation strengthening, leading to the tensile strength improved of SAC105. When Ni is substituted by Bi, the tensile strength is further enhanced with a considerable tensile ductility higher than 25%, which still meets the practical demands. At the same time, the melting point is reduced, the wettability is improved, and the creep resistance is enhanced. Among all the investigated solders, SAC105-2Sb-4.4In-0.3Bi alloy possesses the optimized properties, i.e., the lowest melting point, the best wettability, and the highest creep resistance at room temperature, implying that element alloying plays a vital role in improving the performance of SAC105 solders.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114059
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4060: Synthesis and Electrical Percolation of
Highly Amorphous Polyvinyl Alcohol/Reduced Graphene Oxide Nanocomposite
Authors: Renata Adami, Patrizia Lamberti, Marcello Casa, Nicole D’Avanzo, Eleonora Ponticorvo, Claudia Cirillo, Maria Sarno, Dzmitry Bychanok, Polina Kuzhir, Changjiang Yu, Hesheng Xia, Paolo Ciambelli
First page: 4060
Abstract: Polyvinyl alcohol is the most commercially water-soluble biodegradable polymer, and it is in use for a wide range of applications. It shows good compatibility with most inorganic/organic fillers, and enhanced composites may be prepared without the need to introduce coupling agents and interfacial modifiers. The patented high amorphous polyvinyl alcohol (HAVOH), commercialized with the trade name G-Polymer, can be easily dispersed in water and melt processed. HAVOH is particularly suitable for extrusion and can be used as a matrix to disperse nanocomposites with different properties. In this work, the optimization of the synthesis and characterization of HAVOH/reduced graphene oxide (rGO) nanocomposite obtained by the solution blending process of HAVOH and Graphene Oxide (GO) water solutions and ‘in situ’ reduction of GO is studied. The produced nanocomposite presents a low percolation threshold (~1.7 wt%) and high electrical conductivity (up to 11 S/m) due to the uniform dispersion in the polymer matrix as a result of the solution blending process and the good reduction level of GO. In consideration of HAVOH processability, the conductivity obtained by using rGO as filler, and the low percolation threshold, the nanocomposite presented here is a good candidate for the 3D printing of a conductive structure.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114060
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4061: Topological Design of a Hinger Bracket
Based on Additive Manufacturing
Authors: Baocheng Xie, Xilong Wu, Le Liu, Yuan Zhang
First page: 4061
Abstract: Topology optimization technology is often used in the design of lightweight structures under the condition that mechanical performance should be guaranteed, but a topology-optimized structure is often complicated and difficult to process using traditional machining technology. In this study, the topology optimization method, with a volume constraint and the minimization of structural flexibility, is applied to the lightweight design of a hinge bracket for civil aircraft. A mechanical performance analysis is conducted using numerical simulations to obtain the stress and deformation of the hinge bracket before and after topology optimization. The numerical simulation results show that the topology-optimized hinge bracket has good mechanical properties, and its weight was reduced by 28% compared with the original design of the model. In addition, the hinge bracket samples before and after topology optimization are prepared with additive manufacturing technology and mechanical performance tests are conducted using a universal mechanical testing machine. The test results show that the topology-optimized hinge bracket can satisfy the mechanical performance requirements of a hinge bracket at a weight loss ratio of 28%.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114061
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4062: Effect of Annular Laser Metal Deposition
(ALMD) Process Parameters on Track Geometry and Thermal History on Ti6Al4V
Alloy Clad
Authors: Jinchao Zhang, Yupeng Cao, Heng Wang, Tuo Shi, Boyong Su, Lei Zhang
First page: 4062
Abstract: Annular laser metal deposition (ALMD) is a rising technology that fabricates near-net-shaped components. In this research, a single factor experiment with 18 groups was designed to study the influence of process parameters on the geometric characteristics (bead width, bead height, fusion depth, and fusion line) and thermal history of Ti6Al4V tracks. The results show that discontinuous and uneven tracks with pores or large-sized incomplete fusion defects were observed when the laser power was less than 800 W or the defocus distance was −5 mm. The laser power had a positive effect on the bead width and height, while the scanning speed had the opposite effect. The shape of the fusion line varied at different defocus distances, and the straight fusion line could be obtained with the appropriate process parameters. The scanning speed was the parameter that had the greatest effect on the molten pool lifetime and solidification time as well as the cooling rate. In addition, the microstructure and microhardness of the thin wall sample were also studied. Many clusters with various sizes in different zones were distributed within the crystal. The microhardness ranged from 330 HV to 370 HV.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114062
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4063: Simulation of Internal Defects in TKX-50
Crystals
Authors: Siqi Qiu, Xue Zhao, Yuanyuan Li, Wenyuan Ding, Junrui Huang
First page: 4063
Abstract: 1,1′-Dihydroxy-5,5′-bi-tetrazolium dihydroxylamine salt (TKX-50) is a new type of high-energy low-sense explosive with great application value, but TKX-50 made directly from the reaction has problems such as irregular crystal morphology and relatively large length-diameter, and these factors seriously affect the sensitivity of TKX-50 and limit its large-scale application. The internal defects of TKX-50 crystals have a great influence on their weakness, and studying its related properties is of great theoretical significance and application value. To further investigate the microscopic properties of TKX-50 crystals and to explore the connection between microscopic parameters and macroscopic susceptibility, this paper reports the use of molecular dynamics simulations to construct TKX-50 crystal scaling models with three types of defects—vacancy, dislocation and doping—and conducts molecular dynamics simulations. The influence of TKX-50 crystal defects on the initiation bond length, density, bonding diatomic interaction energy, and cohesive energy density of the crystal was obtained. The simulation results show that the models with a higher bond length of the initiator bond and higher percentage activated the initiator’s N-N bond and lowered the bond-linked diatomic energy, cohesive energy density, and density corresponding to higher crystal sensitivities. This led to a preliminary connection between TKX-50 microscopic model parameters and macroscopic susceptibility. The results of the study can provide a reference for the design of subsequent experiments, and the research method can be extended to the research work on other energy-containing materials.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114063
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4064: Computational Study of the Influence of
α/β-Phase Ratio and Porosity on the Elastic Modulus of Ti-Based
Alloy Foams
Authors: Claudio Aguilar, Javier Henriquez, Christopher Salvo, Ismelí Alfonso, Nicolas Araya, Lisa Muñoz
First page: 4064
Abstract: This work aims to perform a computational analysis on the influence that microstructure and porosity have on the elastic modulus of Ti-6Al-4V foams used in biomedical applications with different α/β-phase ratios. The work is divided into two analyses, first the influence that the α/β-phase ratio has and second the effects that porosity and α/β-phase ratio have on the elastic modulus. Two microstructures were analyzed: equiaxial α-phase grains + intergranular β-phase (microstructure A) and equiaxial β-phase grains + intergranular α-phase (microstructure B). The α/β-phase ratio was variated from 10 to 90% and the porosity from 29 to 56%. The simulations of the elastic modulus were carried out using finite element analysis (FEA) using ANSYS software v19.3. The results were compared with experimental data reported by our group and those found in the literature. The β-phase amount and porosity have a synergic effect on the elastic modulus, for example, when the foam has a porosity of 29 with 0% β-phase, and it has an elastic modulus of ≈55 GPa, but when the β-phase amount increases to 91%, the elastic modulus decreases as low as 38 GPa. The foams with 54% porosity have values smaller than 30 GPa for all the β-phase amounts.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114064
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4065: Development of Alkali Activated Inorganic
Foams Based on Construction and Demolition Wastes for Thermal Insulation
Applications
Authors: Adrienn Boros, Gábor Erdei, Tamás Korim
First page: 4065
Abstract: Nowadays, the construction industry is challenged not only by increasingly strict environmental regulations, but also by a shortage of raw materials and additives. It is critical to find new sources with which the circular economy and zero waste approach can be achieved. Promising candidates are alkali activated cements (AAC), which offer the potential to convert industrial wastes into higher added value products. The aim of the present research is to develop waste-based AAC foams with thermal insulation properties. During the experiments, pozzolanic materials (blast furnace slag, fly ash, and metakaolin) and waste concrete powder were used to produce first dense and then foamed structural materials. The effects of the concrete fractions, the relative proportions of each fraction, the liquid/solid ratio, and the amount of foaming agents on the physical properties were investigated. A correlation between macroscopic properties (strength, porosity, and thermal conductivity) and micro/macro structure was examined. It was found that concrete waste itself is suitable for the production of AACs, but when combined with other aluminosilicate source, the strength can be increased from 10 MPa up to 47 MPa. The thermal conductivity (0.049 W/mK) of the produced non-flammable foams is comparable to commercially available insulating materials.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114065
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4066: Coupled Effects of Temperature and
Humidity on Fracture Toughness of Al–Mg–Si–Mn Alloy
Authors: Ibrahim Alqahtani, Andrew Starr, Muhammad Khan
First page: 4066
Abstract: The combined effect of temperature and humidity on the fracture toughness of aluminium alloys has not been extensively studied, and little attention has been paid due to its complexity, understanding of its behaviour, and difficulty in predicting the effect of the combined factors. Therefore, the present study aims to address this knowledge gap and improve the understanding of the interdependencies between the coupled effects of temperature and humidity on the fracture toughness of Al–Mg–Si–Mn alloy, which can have practical implications for the selection and design of materials in coastal environments. Fracture toughness experiments were carried out by simulating the coastal environments, such as localised corrosion, temperature, and humidity, using compact tension specimens. The fracture toughness increased with varying temperatures from 20 to 80 °C and decreased with variable humidity levels between 40% and 90%, revealing Al–Mg–Si–Mn alloy is susceptible to corrosive environments. Using a curve-fitting approach that mapped the micrographs to temperature and humidity conditions, an empirical model was developed, which revealed that the interaction between temperature and humidity was complex and followed a nonlinear interaction supported by microstructure images of SEM and collected empirical data.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114066
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4067: The Different Welding Layers and Heat
Source Energy on Residual Stresses in Swing Arc Narrow Gap MAG Welding
Authors: Yuan Fang, Chunwei Ma, Guangkai Zhang, Yuli Qin, Wentao Cao
First page: 4067
Abstract: In this paper, in order to reduce the time cost of prediction experiments in industry, a new narrow gap oscillation calculation method is developed in ABAQUS thermomechanical coupling analysis to study the distribution trend of residual weld stresses in comparison with conventional multi-layer welding processes. The blind hole detection technique and thermocouple measurement method verify the reliability of the prediction experiment. The results show that the experimental and simulation results have a high degree of agreement. In the prediction experiments, the calculation time of the high-energy single-layer welding experiments is 1/4 of the traditional multi-layer welding. Two welding processes of longitudinal residual stress and transverse residual stress distribution trends are the same. The high-energy single-layer welding experiment stress distribution range and transverse residual stress peak are smaller, but the longitudinal residual stress peak is slightly higher, which can be effectively reduced by increasing the preheating temperature of the welded parts. This implies that in the specific case of increasing the initial temperature of the workpiece, the use of high-energy single-layer welding instead of multi-layer welding to study the residual stress distribution trend not only optimizes the weld quality but also reduces the time cost to a large extent.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114067
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4068: A Research Investigation into the Impact
of Reinforcement Distribution and Blast Distance on the Blast Resilience
of Reinforced Concrete Slabs
Authors: Yangyong Wu, Jianhui Wang, Fei Liu, Chaomin Mu, Ming Xia, Shaokang Yang
First page: 4068
Abstract: Reinforcement is one of the important factors affecting the anti-blast performance of reinforced concrete (RC) slabs. In order to study the impact of different reinforcement distribution and different blast distances on the anti-blast performance of RC slabs, 16 model tests were carried out for RC slab members with the same reinforcement ratio but different reinforcement distribution and the same proportional blast distance but different blast distances. By comparing the failure patterns of RC slabs and the sensor test data, the impact of reinforcement distribution and blast distance on the dynamic response of RC slabs was analyzed. The results show that, under contact explosion and non-contact explosion, the damage degree of single-layer reinforced slabs is more serious than that of double-layer reinforced slabs. When the scale distance is the same, with the increase of distance, the damage degree of single-layer reinforced slabs and double-layer reinforced slabs increases first and then decreases, and the peak displacement, rebound displacement and residual deformation near the center of the bottom of RC slabs gradually increase. When the blast distance is small, the peak displacement of single-layer reinforced slabs is smaller than that of double-layer reinforced slabs. When the blast distance is large, the peak displacement of double-layer reinforced slabs is smaller than that of single-layer reinforced slabs. No matter how large the blast distance, the rebound peak displacement of the double-layer reinforced slabs is smaller, and the residual displacement is larger. The research in this paper provides a reference for the anti-explosion design, construction and protection of RC slabs.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114068
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4069: Coupling Computational Homogenization with
Crystal Plasticity Modelling for Predicting the Warm Deformation Behaviour
of AA2060-T8 Al-Li Alloy
Authors: Ali Abd El-Aty, Sangyul Ha, Yong Xu, Yong Hou, Shi-Hong Zhang, Bandar Alzahrani, Alamry Ali, Mohamed M. Z. Ahmed
First page: 4069
Abstract: This study aimed to propose a new approach for predicting the warm deformation behaviour of AA2060-T8 sheets by coupling computational homogenization (CH) with crystal plasticity (CP) modeling. Firstly, to reveal the warm deformation behaviour of the AA2060-T8 sheet, isothermal warm tensile testing was accomplished using a Gleeble-3800 thermomechanical simulator at the temperatures and strain rates that varied from 373 to 573 K and 0.001 to 0.1 s−1. Then, a novel crystal plasticity model was proposed for describing the grains’ behaviour and reflecting the crystals’ actual deformation mechanism under warm forming conditions. Afterward, to clarify the in-grain deformation and link the mechanical behaviour of AA2060-T8 with its microstructural state, RVE elements were created to represent the microstructure of AA2060-T8, where several finite elements discretized every grain. A remarkable accordance was observed between the predicted results and their experimental counterparts for all testing conditions. This signifies that coupling CH with CP modelling can successfully determine the warm deformation behaviour of AA2060-T8 (polycrystalline metals) under different working conditions.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114069
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4070: Elimination of a Mixture of Microplastics
Using Conventional and Detergent-Assisted Coagulation
Authors: Sabina Ziembowicz, Małgorzata Kida, Piotr Koszelnik
First page: 4070
Abstract: The research described here investigated the suitability of coagulation process in the elimination of microplastics from tap water. The purpose of the study was to assess the effects of microplastic type (PE1, PE2, PE3, PVC1, PVC2, and PVC3), tap water pH (3, 5, 7, and 9), coagulant doses (0, 0.025, 0.05, 0.1 and 0.2 g/L), and microplastic concentration (0.05, 0.1, 0.15, and 0.2 g/L) on elimination efficiency with coagulation utilizing Al and Fe coagulants as well coagulation combined with a detergent (SDBS) addition. This work also explores the elimination of a mixture of two microplastics (PE and PVC) that are significant in terms of the environment. The effectiveness of conventional and detergent-assisted coagulation was calculated as a percentage. The fundamental characteristics of microplastics were also determined via LDIR analysis, and on the basis of these findings, particles that were more coagulation-prone were identified. The maximum reduction in MPs was achieved with tap water’s neutral pH and a coagulant dosage of 0.05 g/L. The addition of SDBS increased the loss of the plastic microparticles’ efficacy. A removal efficiency of greater than 95% (Al-coagulant) and 80% (Fe-coagulant) was achieved for each of the microplastics tested. The removal efficiency of the microplastic mixture with SDBS-assisted coagulation was obtained at a level of 95.92% (AlCl3·6H2O) and 98.9% (FeCl3·6H2O). After each coagulation procedure, the mean circularity and solidity of the unremoved particles increased. This confirmed that particles with irregular shapes are easier to completely remove.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114070
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4071: Achievement of High Perpendicular
Anisotropy and Modification of Heat Treatment Peeling in Micron-Thickness
Nd-Fe-B Films Used for Magnetic MEMS
Authors: Jingbin Huang, Zhanyong Wang, Shijie Liao, Fang Wang, Min Huang, Jian Zhang
First page: 4071
Abstract: Thick Nd-Fe-B permanent magnetic films with good perpendicular anisotropy have important applications in magnetic microelectromechanical systems (MEMSs). However, when the thickness of the Nd-Fe-B film reaches the micron level, the magnetic anisotropy and texture of NdFeB film will become worse, and it is also prone to peeling during heat treatment, which seriously limits their applications. In this paper, Si(100)/Ta(100 nm)/NdxFe91−xB9(x = 14.5, 16.4, 18.2)/Ta (100 nm) films with thicknesses of 2–10 μm are prepared by magnetron sputtering. It is found that gradient annealing (GN) could help improve the magnetic anisotropy and texture of the micron-thickness film. When the Nd-Fe-B film thickness increases from 2 μm to 9 μm, its magnetic anisotropy and texture do not deteriorate. For the 9 μm Nd-Fe-B film, a high coercivity of 20.26 kOe and high magnetic anisotropy (remanence ratio Mr/Ms = 0.91) are achieved. An in-depth analysis of the elemental composition of the film along the thickness direction is conducted, and the presence of Nd aggregation layers at the interface between the Nd-Fe-B and the Ta layers is confirmed. The influence of thicknesses of the Ta buffer layer on the peeling of Nd-Fe-B micron-thickness films after high-temperature annealing is investigated, and it is found that increasing the thickness of the Ta buffer layer could effectively inhibit the peeling of Nd-Fe-B films. Our finding provides an effective way to modify the heat treatment peeling of Nd-Fe-B films. Our results are important for the development of Nd-Fe-B micron-scale films with high perpendicular anisotropy for applications in magnetic MEMS.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114071
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4072: Aero-Engine Blade Cryogenic Cooling
Milling Deformation Simulation and Process Parameter Optimization
Authors: Ting Chen, Yun Xu, Bo Huang, Yan Shi, Jiahu Zhang, Lei Li, Yaozhi Meng, Xuqing Li
First page: 4072
Abstract: For the machining of aero-engine blades, factors such as machining residual stress, milling force, and heat deformation can result in poor blade profile accuracy. To address this issue, simulations of blade milling were completed using DEFORM11.0 and ABAQUS2020 software to analyze blade deformation under heat-force fields. Process parameters such as spindle speed, feed per tooth, depth of cut, and jet temperature are used to design both a single-factor control and BBD test scheme to study the influence of jet temperature and multiple changes in process parameters on blade deformation. The multiple quadratic regression method was applied to establish a mathematical model correlating blade deformation with process parameters, and a preferred set of process parameters was obtained through the particle swarm algorithm. Results from the single-factor test indicated that blade deformation rates were reduced by more than 31.36% in low-temperature milling (−190 °C to −10 °C) compared with dry milling (10 °C to 20 °C). However, the margin of the blade profile exceeded the permissible range (±50 µm); therefore, the particle swarm optimization algorithm was used to optimize machining process parameters, resulting in a maximum deformation of 0.0396 mm when the blade temperature was −160 °C~−180 °C, meeting the allowable blade profile deformation error.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114072
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4073: Possibilities of Using Selected Additive
Methods for the Production of Polymer Harmonic Drive Prototypes
Authors: Jacek Pacana, Andrzej Pacana, Rafał Oliwa
First page: 4073
Abstract: This article includes an analysis of the possibility of using polymer materials for the production of harmonic drive. The use of additive methods greatly eases and accelerates the manufacturing of the flexspline. In the case of gears made of polymeric materials using rapid prototyping (RP) methods, the problem is often with their mechanical strength. In a harmonic drive, the wheel is uniquely exposed to damage, because during work, it deforms and is additionally loaded with torque. Therefore, numerical calculations were conducted using the finite element method (FEM) in the Abaqus program. As a result, information was obtained on the distribution of stresses in the flexspline and their maximum values. On this basis, it was possible to determine whether a flexspline made of specific polymers could be used in commercial harmonic drives or whether they were only adequate for the production of prototypes.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114073
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4074: Thermomechanical Peridynamic Modeling for
Ductile Fracture
Authors: Shankun Liu, Fei Han, Xiaoliang Deng, Ye Lin
First page: 4074
Abstract: In this paper, we propose a modeling method based on peridynamics for ductile fracture at high temperatures. We use a thermoelastic coupling model combining peridynamics and classical continuum mechanics to limit peridynamics calculations to the failure region of a given structure, thereby reducing computational costs. Additionally, we develop a plastic constitutive model of peridynamic bonds to capture the process of ductile fracture in the structure. Furthermore, we introduce an iterative algorithm for ductile-fracture calculations. We present several numerical examples illustrating the performance of our approach. More specifically, we simulated the fracture processes of a superalloy structure in 800 ℃ and 900 ℃ environments and compared the results with experimental data. Our comparisons show that the crack modes captured by the proposed model are similar to the experimental observations, verfying the validity of the proposed model.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114074
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4075: Green Nanomaterials for Smart Textiles
Dedicated to Environmental and Biomedical Applications
Authors: Melania Popescu, Camelia Ungureanu
First page: 4075
Abstract: Smart textiles recently reaped significant attention owing to their potential applications in various fields, such as environmental and biomedical monitoring. Integrating green nanomaterials into smart textiles can enhance their functionality and sustainability. This review will outline recent advancements in smart textiles incorporating green nanomaterials for environmental and biomedical applications. The article highlights green nanomaterials’ synthesis, characterization, and applications in smart textile development. We discuss the challenges and limitations of using green nanomaterials in smart textiles and future perspectives for developing environmentally friendly and biocompatible smart textiles.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114075
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4076: Description of Material Properties of
Degraded and Damaged Segments of Multi-Leaf Masonry in Analyses of Large
Three-Dimensional Structures
Authors: Czesław Miedziałowski, Adam Walendziuk
First page: 4076
Abstract: This article focuses on the description of material properties of segments of masonry structures in three-dimensional analyses. It mainly considers degraded and damaged multi-leaf masonry walls. In the beginning, the causes of degradation and damage to masonry are described with examples. It was reported that the analysis of such structures is difficult due to the adequate description of the mechanical properties in the individual segments of the structure and the amount of computational cost of large three-dimensional structures. Next, a method of describing large fragments of masonry structures by means of macro-elements was proposed. The formulation of such macro-elements in three-dimensional and two-dimensional problems was given by introducing limits of variation in material parameters and damage of structures expressed by the limits of integration of macro-elements with specified internal structures. Then, it was stated that such macro-elements can be used to build computational models by the finite element method, which allows the analysis of the deformation–stress state, and at the same time, reduce the number of unknowns in such issues. A strategy for performing analyses and examples of practical applications in masonry analyses were proposed. It was reported that the results of the analyses can be used to plan the repairs and strengthening of structures. Finally, the conducted considerations and proposals were summarised, as well as examples of practical applications.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114076
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4077: Atomic Layer Deposition of HfO2 Films
Using TDMAH and Water or Ammonia Water
Authors: Sylwia Gieraltowska, Lukasz Wachnicki, Piotr Dluzewski, Bartlomiej S. Witkowski, Marek Godlewski, Elzbieta Guziewicz
First page: 4077
Abstract: Atomic layer deposition of HfO2 from TDMAH and water or ammonia water at different temperatures below 400 °C is studied. Growth per cycle (GPC) has been recorded in the range of 1.2–1.6 Å. At low temperatures (≤100 °C), the films grew faster and are structurally more disordered, amorphous and/or polycrystalline with crystal sizes up to 29 nm, compared to the films grown at higher temperatures. At high temperatures of 240 °C, the films are better crystallized with crystal sizes of 38–40 nm but grew slower. GPC, dielectric constant, and crystalline structure are improved by depositing at temperatures above 300 °C. The dielectric constant value and the roughness of the films have been determined for monoclinic HfO2, a mixture of orthorhombic and monoclinic, as well as for amorphous HfO2. Moreover, the present study shows that the increase in the dielectric constant of the films can be achieved by using ammonia water as an oxygen precursor in the ALD growth. The detailed investigations of the relationship between HfO2 properties and growth parameters presented here have not been reported so far, and the possibilities of fine-tuning and controlling the structure and performance of these layers are still being sought.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114077
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4078: Preparation and Characterization of
Crosslinked Electrospun Gelatin Fabrics via Maillard Reactions
Authors: Duangkamol Dechojarassri, Ryota Kaneshige, Hiroshi Tamura, Tetsuya Furuike
First page: 4078
Abstract: In this study, nonwoven gelatin (Gel) fabrics crosslinked using N-acetyl-D-glucosamine (GlcNAc) were characterized and compared with those crosslinked using methylglyoxal (MG) and by thermal dehydration. We prepared Gel with 25% concentration along with Gel/GlcNAc and Gel/MG with a GlcNAc-to-Gel ratio of 5% and MG-to-Gel ratio of 0.6%. A high voltage of 23 kV, solution temperature of 45 °C, and distance of 10 cm between the tip and the collector were applied during electrospinning. The electrospun Gel fabrics were crosslinked by heat treatment at 140 and 150 °C for 1 d. The electrospun Gel/GlcNAc fabrics were treated at 100 and 150 °C for 2 d, while the Gel/MG fabrics were heat-treated for 1 d. The Gel/MG fabrics exhibited higher tensile strength and lower elongation than the Gel/GlcNAc fabrics. Overall, Gel/MG crosslinked at 150 °C for 1 d showed a significant enhancement in tensile strength, high hydrolytic degradation, and excellent biocompatibility, with cell viability percentages of 105 and 130% at 1 and 3 d, respectively. Therefore, MG is a promising Gel crosslinker.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114078
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4079: Method of Determining Kinetic Parameters
of Strength Recovery in Self-Healing Ceramic Composites
Authors: Mostafizur Rahman, Taiyo Maeda, Toshio Osada, Shingo Ozaki
First page: 4079
Abstract: Self-healing ceramic composites are promising smart materials for high-temperature applications. Experimental and numerical studies have been performed to more fully understand their behaviors, and kinetic parameters such as the activation energy and frequency factor have been reported to be indispensable for investigating healing phenomena. This article proposes a method of determining the kinetic parameters of self-healing ceramic composites using the oxidation kinetics model of strength recovery. These parameters are determined by an optimization method using experimental strength recovery data under various healing temperatures, times, and microstructural features on the fractured surfaces. Alumina and mullite matrix-based self-healing ceramic composites such as Al2O3/SiC, Al2O3/TiC, Al2O3/Ti2AlC (MAX phase), and mullite/SiC, were selected as the target materials. The theoretical strength recovery behaviors of the cracked specimens obtained from the kinetic parameters were compared with the experimental results. The parameters were within the previously reported ranges, and the predicted strength recovery behaviors reasonably agreed with the experimental values. The proposed method can also be applied to other self-healing ceramics with matrices reinforced with different healing agents to evaluate oxidation rate, crack healing rate, and theoretical strength recovery behaviors to design self-healing materials used in high-temperature applications. Furthermore, the healing ability of composites can be discussed regardless of the type of strength recovery test.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114079
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4080: Biocompatibility, Surface Morphology, and
Bacterial Load of Dental Implant Abutments Following Decontamination
Protocols: An In-Vitro Study
Authors: Esi Sharon, Yoav Pietrokovski, Ilana Engel, Rula Assali, Yael Houri-Haddad, Nurit Beyth
First page: 4080
Abstract: The long-term success of dental implant rehabilitation depends significantly on proper peri-implant soft tissue integration. Therefore, decontamination of abutments prior to their connection to the implant is beneficial to enhance soft tissue attachment and to aid in maintaining marginal bone around the implant. Consequently, different implant abutment decontamination protocols were evaluated regarding biocompatibility, surface morphology, and bacterial load. The protocols evaluated were autoclave sterilization, ultrasonic washing, steam cleaning, chlorhexidine chemical decontamination, and sodium hypochlorite chemical decontamination. The control groups included: (1) implant abutments prepared and polished in a dental lab without decontamination and (2) unprepared implant abutments obtained directly from the company. Surface analysis was performed using scanning electron microscopy (SEM). Biocompatibility was evaluated using XTT cell viability and proliferation assays. Biofilm biomass and viable counts (CFU/mL) (n = 5 for each test) were used for surface bacterial load evaluation. Surface analysis revealed areas of debris and accumulation of materials, such as iron, cobalt, chromium, and other metals, in all abutments prepared by the lab and with all decontamination protocols. Steam cleaning was the most efficient method for reducing contamination. Chlorhexidine and sodium hypochlorite left residual materials on the abutments. XTT results showed that the chlorhexidine group (M = 0.7005, SD = 0.2995) had the lowest values (p < 0.001) (autoclave: M = 3.6354, SD = 0.1510; ultrasonic: M = 3.4077, SD = 0.3730; steam: M = 3.2903, SD = 0.2172; NaOCl: M = 3.5377, SD = 0.0927; prep non-decont.: M = 3.4815, SD = 0.2326; factory: M = 3.6173, SD = 0.0392). Bacterial growth (CFU/mL) was high in the abutments treated with steam cleaning and ultrasonic bath: 2.93 × 109, SD = 1.68 × 1012 and 1.83 × 109, SD = 3.95 × 1010, respectively. Abutments treated with chlorhexidine showed higher toxicity to cells, while all other samples showed similar effects to the control. In conclusion, steam cleaning seemed to be the most efficient method for reducing debris and metallic contamination. Bacterial load can be reduced using autoclaving, chlorhexidine, and NaOCl.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114080
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4081: Corrosion Behavior of Alumina-Forming
Austenitic Steel in Supercritical Carbon Dioxide Conditions: Effects of Nb
Content and Temperature
Authors: Zhaodandan Ma, Shuo Cong, Huan Chen, Zhu Liu, Yuanyuan Dong, Rui Tang, Tian Qiu, Yong Chen, Xianglong Guo
First page: 4081
Abstract: The corrosion behavior of alumina-forming austenitic (AFA) stainless steels with different Nb additions in a supercritical carbon dioxide environment at 500 °C, 600 °C, and 20 MPa was investigated. The steels with low Nb content were found to have a novel structure with a double oxide as an outer Cr2O3 oxide film and an inner Al2O3 oxide layer with discontinuous Fe-rich spinels on the outer surface and a transition layer consisting of Cr spinels and γ’-Ni3Al phases randomly distributed under the oxide layer. Oxidation resistance was improved by accelerating diffusion through refined grain boundaries after the addition of 0.6 wt.% Nb. However, the corrosion resistance decreased significantly at higher Nb content due to the formation of continuous thick outer Fe-rich nodules on the surface and an internal oxide zone, and Fe2(Mo, Nb) laves phases were also detected, which prevented the outward diffusion of Al ions and promoted the formation of cracks within the oxide layer, resulting in unfavorable effects on oxidation. After exposure at 500 °C, fewer spinels and thinner oxide scales were found. The specific mechanism was discussed.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114081
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4082: Modeling and Optimizing the Crystal Violet
Dye Adsorption on Kaolinite Mixed with Cellulose Waste Red Bean Peels:
Insights into the Kinetic, Isothermal, Thermodynamic, and Mechanistic
Study
Authors: Razika Mecheri, Ammar Zobeidi, Salem Atia, Salah Neghmouche Nacer, Alsamani A. M. Salih, Mhamed Benaissa, Djamel Ghernaout, Saleh Al Arni, Saad Ghareba, Noureddine Elboughdiri
First page: 4082
Abstract: In this study, a new eco-friendly kaolinite–cellulose (Kaol/Cel) composite was prepared from waste red bean peels (Phaseolus vulgaris) as a source of cellulose to serve as a promising and effective adsorbent for the removal of crystal violet (CV) dye from aqueous solutions. Its characteristics were investigated through the use of X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and zero-point of charge (pHpzc). The Box–Behnken design was used to improve CV adsorption on the composite by testing its primary affecting factors: loading Cel into the composite matrix of Kaol (A: 0–50%), adsorbent dosage (B: 0.02–0.05 g), pH (C: 4–10), temperature (D: 30–60 °C), and duration (E: 5–60 min). The significant interactions with the greatest CV elimination efficiency (99.86%) are as follows: BC (adsorbent dose vs. pH) and BD (adsorbent dose vs. temperature) at optimum parameters (A: 25%, B: 0.05 g, C: 10, D: 45 °C, and E: 17.5 min) for which the CV’s best adsorption capacity (294.12 mg/g) was recorded. The Freundlich and pseudo-second-order kinetic models were the best isotherm and kinetic models fitting our results. Furthermore, the study investigated the mechanisms responsible for eliminating CV by utilizing Kaol/Cel–25. It detected multiple types of associations, including electrostatic, n-π, dipole–dipole, hydrogen bonding interactions, and Yoshida hydrogen bonding. These findings suggest that Kaol/Cel could be a promising starting material for developing a highly efficient adsorbent that can remove cationic dyes from aqueous environments.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114082
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4083: Assessment of the Suitability of Coke
Material for Proppants in the Hydraulic Fracturing of Coals
Authors: Suponik, Labus, Morga
First page: 4083
Abstract: To enhance the extraction of methane gas from coal beds, hydraulic fracturing technology is used. However, stimulation operations in soft rocks, such as coal beds, are associated with technical problems related mainly to the embedment phenomenon. Therefore, the concept of a novel coke-based proppant was introduced. The purpose of the study was to identify the source coke material for further processing to obtain a proppant. Twenty coke materials differing in type, grain size, and production method from five coking plants were tested. The values of the following parameters were determined for the initial coke: micum index 40; micum index 10; coke reactivity index; coke strength after reaction; and ash content. The coke was modified by crushing and mechanical classification, and the 3–1 mm class was obtained. This was enriched in heavy liquid with a density of 1.35 g/cm3. The crush resistance index and Roga index, which were selected as key strength parameters, and the ash content were determined for the lighter fraction. The most promising modified coke materials with the best strength properties were obtained from the coarse-grained (fraction 25–80 mm and greater) blast furnace and foundry coke. They had crush resistance index and Roga index values of at least 44% and at least 96%, respectively, and contained less than 9% ash. After assessing the suitability of coke material for proppants in the hydraulic fracturing of coal, further research will be needed to develop a technology to produce proppants with parameters compliant with the PN-EN ISO 13503-2:2010 standard.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114083
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4084: Optimization of the Filler-and-Binder
Mixing Ratio for Enhanced Mechanical Strength of Carbon–Carbon
Composites
Authors: Ji-Hong Kim, Hye-In Hwang, Ji-Sun Im
First page: 4084
Abstract: In this paper, a method for optimizing the mixing ratio of filler coke and binder for high-strength carbon–carbon composites is proposed. Particle size distribution, specific surface area, and true density were analyzed to characterize the filler properties. The optimum binder mixing ratio was experimentally determined based on the filler properties. As the filler particle size was decreased, a higher binder mixing ratio was required to enhance the mechanical strength of the composite. When the d50 particle size of the filler was 62.13 and 27.10 µm, the required binder mixing ratios were 25 and 30 vol.%, respectively. From this result, the interaction index, which quantifies the interaction between the coke and binder during carbonization, was deduced. The interaction index had a higher correlation coefficient with the compressive strength than that of the porosity. Therefore, the interaction index can be used in predicting the mechanical strength of carbon blocks and optimizing their binder mixing ratios. Furthermore, as it is calculated from the carbonization of blocks without additional analysis, the interaction index can be easily used in industrial applications.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114084
Issue No: Vol. 16, No. 11 (2023)
- Materials, Vol. 16, Pages 4085: Friction Stir Welding of Dissimilar Al
6061-T6 to AISI 316 Stainless Steel: Microstructure and Mechanical
Properties
Authors: Mohamed Newishy, Matias Jaskari, Antti Järvenpää, Hidetoshi Fujii, Hamed Ahmed Abdel-Aleem
First page: 4085
Abstract: The friction stir welding (FSW) process was recently developed to overcome the difficulty of welding non-ferrous alloys and steels. In this study, dissimilar butt joints between 6061-T6 aluminum alloy and AISI 316 stainless steel were welded by FSW using different processing parameters. The grain structure and precipitates at the different welded zones of the various joints were intensively characterized by the electron backscattering diffraction technique (EBSD). Subsequently, the FSWed joints were tensile tested to examine the mechanical strength compared with that of the base metals. The micro-indentation hardness measurements were conducted to reveal the mechanical responses of the different zones in the joint. The EBSD results of the microstructural evolution showed that a significant continuous dynamic recrystallization (CDRX) occurred in the stir zone (SZ) of the Al side, which was mainly composed of the weak metal, Al, and fragmentations of the steel. However, the steel underwent severe deformation and discontinuous dynamic recrystallization (DDRX). The FSW rotation speed increased the ultimate tensile strength (UTS) from 126 MPa at a rotation speed of 300 RPM to 162 MPa at a rotation speed of 500 RPM. The tensile failure occurred at the SZ on the Al side for all specimens. The impact of the microstructure change in the FSW zones was significantly pronounced in the micro-indentation hardness measurements. This was presumably attributed to the promotion of various strengthening mechanisms, such as grain refinement due to DRX (CDRX or DDRX), the appearance of intermetallic compounds, and strain hardening. The aluminum side underwent recrystallization as a result of the heat input in the SZ, but the stainless steel side did not experience recrystallization due to inadequate heat input, resulting in grain deformation instead.
Citation: Materials
PubDate: 2023-05-30
DOI: 10.3390/ma16114085
Issue No: Vol. 16, No. 11 (2023)
