Subjects -> MATHEMATICS (Total: 1013 journals)     - APPLIED MATHEMATICS (92 journals)    - GEOMETRY AND TOPOLOGY (23 journals)    - MATHEMATICS (714 journals)    - MATHEMATICS (GENERAL) (45 journals)    - NUMERICAL ANALYSIS (26 journals)    - PROBABILITIES AND MATH STATISTICS (113 journals) MATHEMATICS (714 journals)            First | 1 2 3 4
 Showing 601 - 538 of 538 Journals sorted alphabetically Results in Control and Optimization Results in Mathematics Results in Nonlinear Analysis Review of Symbolic Logic       (Followers: 2) Reviews in Mathematical Physics       (Followers: 1) Revista Baiana de Educação Matemática Revista Bases de la Ciencia Revista BoEM - Boletim online de Educação Matemática Revista Colombiana de Matemáticas       (Followers: 1) Revista de Ciencias Revista de Educación Matemática Revista de la Escuela de Perfeccionamiento en Investigación Operativa Revista de la Real Academia de Ciencias Exactas, Fisicas y Naturales. Serie A. Matematicas Revista de Matemática : Teoría y Aplicaciones       (Followers: 1) Revista Digital: Matemática, Educación e Internet Revista Electrónica de Conocimientos, Saberes y Prácticas Revista Integración : Temas de Matemáticas Revista Internacional de Sistemas Revista Latinoamericana de Etnomatemática Revista Latinoamericana de Investigación en Matemática Educativa Revista Matemática Complutense Revista REAMEC : Rede Amazônica de Educação em Ciências e Matemática Revista SIGMA Ricerche di Matematica RMS : Research in Mathematics & Statistics Royal Society Open Science       (Followers: 7) Russian Journal of Mathematical Physics Russian Mathematics Sahand Communications in Mathematical Analysis Sampling Theory, Signal Processing, and Data Analysis São Paulo Journal of Mathematical Sciences Science China Mathematics       (Followers: 1) Science Progress       (Followers: 1) Sciences & Technologie A : sciences exactes Selecta Mathematica       (Followers: 1) SeMA Journal Semigroup Forum       (Followers: 1) Set-Valued and Variational Analysis SIAM Journal on Applied Mathematics       (Followers: 11) SIAM Journal on Computing       (Followers: 11) SIAM Journal on Control and Optimization       (Followers: 18) SIAM Journal on Discrete Mathematics       (Followers: 8) SIAM Journal on Financial Mathematics       (Followers: 3) SIAM Journal on Mathematics of Data Science       (Followers: 1) SIAM Journal on Matrix Analysis and Applications       (Followers: 3) SIAM Journal on Optimization       (Followers: 12) Siberian Advances in Mathematics Siberian Mathematical Journal Sigmae SILICON SN Partial Differential Equations and Applications Soft Computing       (Followers: 7) Statistics and Computing       (Followers: 14) Stochastic Analysis and Applications       (Followers: 3) Stochastic Partial Differential Equations : Analysis and Computations       (Followers: 2) Stochastic Processes and their Applications       (Followers: 6) Stochastics and Dynamics       (Followers: 2) Studia Scientiarum Mathematicarum Hungarica       (Followers: 1) Studia Universitatis Babeș-Bolyai Informatica Studies In Applied Mathematics       (Followers: 1) Studies in Mathematical Sciences       (Followers: 1) Superficies y vacio Suska Journal of Mathematics Education       (Followers: 1) Swiss Journal of Geosciences       (Followers: 1) Synthesis Lectures on Algorithms and Software in Engineering       (Followers: 2) Synthesis Lectures on Mathematics and Statistics       (Followers: 1) Tamkang Journal of Mathematics Tatra Mountains Mathematical Publications Teaching Mathematics       (Followers: 10) Teaching Mathematics and its Applications: An International Journal of the IMA       (Followers: 4) Teaching Statistics       (Followers: 8) Technometrics       (Followers: 8) The Journal of Supercomputing       (Followers: 1) The Mathematica journal The Mathematical Gazette       (Followers: 1) The Mathematical Intelligencer The Ramanujan Journal The VLDB Journal       (Followers: 2) Theoretical and Mathematical Physics       (Followers: 7) Theory and Applications of Graphs Topological Methods in Nonlinear Analysis Transactions of the London Mathematical Society       (Followers: 1) Transformation Groups Turkish Journal of Mathematics Ukrainian Mathematical Journal Uniciencia Uniform Distribution Theory Unisda Journal of Mathematics and Computer Science Unnes Journal of Mathematics       (Followers: 1) Unnes Journal of Mathematics Education       (Followers: 2) Unnes Journal of Mathematics Education Research       (Followers: 1) Ural Mathematical Journal Vestnik Samarskogo Gosudarstvennogo Tekhnicheskogo Universiteta. Seriya Fiziko-Matematicheskie Nauki Vestnik St. Petersburg University: Mathematics VFAST Transactions on Mathematics       (Followers: 1) Vietnam Journal of Mathematics Vinculum Visnyk of V. N. Karazin Kharkiv National University. Ser. Mathematics, Applied Mathematics and Mechanics       (Followers: 2) Water SA       (Followers: 1) Water Waves Zamm-Zeitschrift Fuer Angewandte Mathematik Und Mechanik       (Followers: 1) ZDM       (Followers: 2) Zeitschrift für angewandte Mathematik und Physik       (Followers: 2) Zeitschrift fur Energiewirtschaft Zetetike

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 SILICONJournal Prestige (SJR): 0.355 Citation Impact (citeScore): 1Number of Followers: 0      Hybrid journal (It can contain Open Access articles) ISSN (Print) 1876-9918 - ISSN (Online) 1876-990X Published by Springer-Verlag  [2469 journals]
• Design and Integration of Vertical TFET and Memristor for Better
Realization of Logical Functions

Abstract: This paper deals the hybridization of tunnel FET with the memristor for better execution of combinational and sequential circuits. Here, device structure of vertical tunnel FET and memristor are designed and their performance parameters are investigated. For transistor designing, we have introduced a 40 nm PIN Vertical Tunnel Field effect transistor as with ferroelectric oxide doped with Silicon material added to the device. Various electrical characteristics like drain current-Vgs, Quasi-Fermi Level (QFL), Electron and hole concentration, and surface potential are executed. It is noted that the Ferro material PIN structure Vertical TFET has superior than normal tunnel FET. The highest ON current of the proposed devices and largest ON/OFF current are claimed to be (1.15 × 10–5 A/µm) and (1011), respectively. Then memristor which shows reduced area, low power dissipation, and high durability is combined with Tunnel FET to implement the logic gates. In this regard, two of the logic circuits XOR and NAND gate implemented for circuit analysis. The implemented logic gates provide valid results when match with the conventional logic. Finally, the role of novel memristive devices; Memristor, conductive bridging RAM, phase change memory (PCM), spin devices along with floating gate transistor and optical device are also investigated and discussed for the replacement of the memristor.
PubDate: 2022-08-06

• Design of a Novel Protein Sensor of High Sensitivity Using a Defective
Ternary Photonic Crystal Nanostructure

Abstract: Protein plays a crucial role in building and repairing tissues so it is vital to develop a sensitive and rapid detection biosensor that can detect the concentration of protein in an aqueous solution. For biosensing applications, photonic sensing is a revolutionary technique that allows accurate measurement. The current work presents a defective ternary photonic crystal based on Si/ Si3N4/ SiO2 layers with a central cavity filled with a solution sample of protein. The photonic structure is employed as a biosensor for protein detection in an aqueous solution. The transfer matrix method (TMM) is used to analyze the photonic structure. The sensitivity of the photonic structure is investigated with the variation of the cavity thickness and the angle of incidence to achieve a high performance of the biosensor. The results reveal that the defect mode localization moves to a lower wavelength region with increasing the angle of incidence while it shifts toward a larger wavelength region with increasing the thickness of the defect layer. Ultra-high sensitivity of 2488.98 nm/RIU is obtained with an angle of incidence of 60° and cavity thickness of 4.5 μm. The suggested photonic structure's simplicity makes it suitable for industrial design employing low-cost and large-scale product nanofabrication processes. It can be used as a biosensor not only for protein detection but for a broad range of purposes in the field of biosensing.
PubDate: 2022-08-05

• Effects of Silicon and Organic Manure on Growth, Fruit Yield, and Quality
of Grape Tomato Under Water-Deficit Stress

Abstract: Mitigation of deleterious effects of drought stress on the growth and productivity of agronomic and horticultural crops warrants urgent and sustainable actions. Soil application of silicon (Si) and organic manure (OM) could play a promising role in alleviating drought-induced adverse effects on crops. A factorial experiment was conducted to evaluate the effects of Si and OM on growth, physiological traits, fruit yield, and quality of grape tomato under water-deficit stress. The experiment consisted of seven different fertilizer doses in which Si and/or OM were applied with or without nitrogen (N) and phosphorus (P) [control (100% NP), 100% NP + 100% OM, 100% NP + 100% Si, 100% NP + 100% OM + 100% Si, 75% NP + 25% OM + 100% Si, 50% NP + 50% OM + 100% Si, and 100% OM + 100% Si] and three soil moisture regimes [100%, 75%, and 50% field capacity (FC)]. Decreasing soil moisture was equally detrimental for all fertilizer doses, which caused an 86–94% reduction in fruit yield and a 79–92% decrease in irrigation water productivity at 50% FC compared with 100% FC. However, the same soil moisture level (50% FC) increased fruit color index by 129% and total soluble solids content by 19% compared with that at 100% FC. Nevertheless, OM application along with the recommended doses of N and P (100% NP + 100% OM) resulted in a better response of grape tomato with 38% higher root dry matter, 21% higher individual fruit weight, 98% higher fruit number plant–1, 145% higher fruit yield, 159% higher irrigation water productivity, and 31% lower proline content compared with the control. This response was at large similar with 100% NP + 100% OM + 100% Si and 50% NP + 50% OM + 100% Si at 100% and 75% FC, especially for fruit yield and irrigation water productivity. Hence, supplementing OM along with the recommended or even half of the recommended doses of N and P as well as supplementation of Si could be a feasible option for grape tomato cultivation under moderate water-deficit stress of up to 75% FC. Growth and yield reduction at 50% FC could not be compensated for the application of OM or Si.
PubDate: 2022-08-05

• Effects of O2 and N2 Gas Concentration on the Formation of Ho2O3 Gate
Oxide on 4H-SiC Substrate

Abstract: In this paper, the impacts of flow concentration of oxynitridation on the structural and electrical performance of a high-κ Ho2O3 dielectric on n-type 4H-SiC were studied. The Ho2O3 films were grown using Physical vapour deposition (PVD) RF magnetron sputtering at various O2 and N2 gas flow concentrations from (25 – 100%), and constant temperature and period of 900 °C and 15 min, respectively. The results of Fourier transform infra-red (FTIR) and X-ray diffraction (XRD) analysis show that cubic c-Ho2O3 and monoclinic (b)-SiO2 crystal structures were formed in between the SiC substrate and the Ho2O3 thin films during thermal oxynitridation. The microstrain and crystallite size were obtained by Williamson-Hall (W–H) plot. The electrical measurements from the MOS capacitor revealed that 50% oxynitridation exhibited the most encouraging electrical results, with the smallest leakage current density of 6.05 × 10–2 A/cm2 at a breakdown field of 7.52 MV/cm and barrier height value of 18.5 eV. These results provide potential and important implications of using Ho2O3/SiC gate stack, validating the usefulness of leakage current density–breakdown electric field measurement in understanding the operation of a gate dielectric in MOS-based devices.
PubDate: 2022-08-04

• Investigation on Thermophysical and Physicochemical Properties of
CaO-SiO2-CaF2-22.5%TiO2 Silica Based Electrode Coating System

Abstract: The present paper aims to study the thermophysical and physicochemical properties of CaO-CaF2-SiO2-22.5% TiO2 based electrode coating for welding the components of advanced ultra-supercritical power plants. The mixture design methodology was used to formulate thirteen coating mixtures to explore the effect of flux coating properties, i.e., density, change in enthalpy, weight loss, thermal conductivity, specific heat, and thermal diffusivity. Flux coating properties play an essential role in achieving better weldments. Fourier transformation and X-ray diffraction were used to analyze electrode coating composition structural behavior. The coating composition was also characterized by using a thermogravimetric analyzer and hot disc apparatus, and after that, a regression model analysis was carried out to study individual, and their interaction effects on the thermophysical and physicochemical properties. CaO.CaF2, CaO.SiO2, and CaF2.SiO2 is the most effective binary mixture which has an increasing effect on density. The weight loss of coating observed during thermogravimetric analysis is affected by individual constituents significantly. The binary interaction of SiO2.CaO and CaF2.SiO2 is the most favorable and has an increasing effect on weight loss. Individual components affect change in enthalpy significantly. The binary interaction of CaO.SiO2 and CaF2.SiO2 is the most effective and has an increasing effect on change in enthalpy. The thermal properties of coating composition observed during hot disc are affected by individual and binary mixture constituents. Binary mixture CaF2.CaO and CaF2.SiO2 is having an increasing effect on thermal conductivity. Binary mixture SiO2.CaO shows a decreasing impact on thermal diffusivity. Binary mixture constituents CaF2.CaO, SiO2.CaO is the most effective and has an increasing effect on specific heat.
PubDate: 2022-08-03

• A Critical Review on Reliability and Short Circuit Robustness of Silicon
Carbide Power MOSFETs

Abstract: Superior electrical and physical properties of SiC (Silicon Carbide) make them ideal for various high voltage, high frequency and high power electronic applications. When compared to GaAs and GaN, the advantage of SiC is that its natural oxide is SiO2 and is used as the gate-dielectric in SiC MOSFETs. Better performance of SiC Power MOSFETs has made it as an ideal substitute to its Si counterpart. Even though the performance of SiC Power MOSFETs has improved significantly over recent years (breakdown voltage over 3300 V [144], field effect channel mobility over 160 cm2/Vs (Cabello et al. in Appl Phys Lett 111, 2017), specific on state resistance as low as 1.63 mΩ.cm2 (Fu et al. in Microelectron Reliab 123, 2021) and short circuit withstand time over 80 µS (Wang et al. in IEEE Trans Power Electron 31:1555–1566, 2016)), reliability issues due to the presence of near interface oxide defects and degradation due to poor quality of interface and gate dielectric is its major drawback. In this article we have extensively studied various reliability and stability issues that affect the performance of Silicon Carbide Power MOSFETs. The short-circuit behaviour and robustness of various SiC Power MOSFETs were also discussed.
PubDate: 2022-08-03

• 1-Bit FinFET Carry Cells for Low Voltage High-Speed Digital Signal
Processing Applications

PubDate: 2022-08-02

• Effect of Process Parameters on Microstructure and Mechanical Properties
of Al-11.5%Si-1%Mg/bimodal SiC(m–n)composites

Abstract: Bimodal size SiC particles reinforced Al-Si alloy composites were fabricated by powder metallurgy route. Three different bimodal reinforcements with various volume fractions of micro and nano sized SiC particles were dispersed in Al-11.5%Si-1%Mg matrix by mechanical alloying for 10 h. The composite powders were hot pressed at 580 °C, 600 °C and 620 °C in a vacuum atmosphere with different cooling rates (10 °C/min, 15 °C/min and 20 °C/min). The microstructural changes of bimodal SiC(m–n) in the matrix material were carried out using OM, SEM and TEM with energy dispersive spectroscopy (EDS). The sample experiments were implemented based on Taguchi L9 OA with three parameters of bimodal reinforcement, sintering temperature and rate of cooling respectively. The measurement of mechanical properties specifies that hardness and tensile strength of Al-11.5%Si-1%Mg composite increases with the decrease of nano-SiC concentration in bimodal reinforcement. Moreover, the fine precipitation of Al-Si rich compound as observed at higher cooling rate (20 °C/min) also contributed for the strength improvement of developing composite.
PubDate: 2022-08-02

• Synthesis of a New Zn2+/Fe3+ Octa(aminopropyl)silsesquioxane Complex and
Its Voltammetric Behavior Towards N-acetylcysteine

Abstract: A zinc-modified octa(aminopropyl)silsesquioxane and the cyan compound Na2[Fe(CN)5NO] were prepared to create a hybrid electroactive material (ACZnN) characterized employing the spectroscopic techniques Raman spectroscopy, Diffuse Reflectance (DR), X-Ray diffraction (XRD), Scanning Electronic Microscopy (SEM), thermogravimetric analysis (TGA) and voltammetric measurements. The cyclic voltammetry technique indicated the solid ACZnN on the electrode surface as presenting two redox processes, with EIθ' = 0.21 V and EIIθ' = 0.51 V (vs Ag/AgCl(sat)) attributed to the redox pair Fe2+(CN)5NO/ Fe3+(CN)5NO in the absence and presence of Zn2+, respectively, as well as adequate stability, reliability and efficiency for practical applications. The ACZnN-modified graphite paste electrode exhibited a sensitive and catalytic oxidation response towards N-acetylcysteine and was successfully employed 1in the catalytic electro-oxidation of N-acetylcysteine employing differential pulse voltammetry techniques. The lowest limit of detection and best amperometric sensitivity obtained by differential pulse voltammetry were 0.657 µmol L−1 and 500 mA/mol L−1, respectively, from 1.0 × 10–6 to 1.0 × 10–5 M. Further analyses applying this method also demonstrated the compound’s efficiency in detecting N-acetylcysteine in synthetic urine samples.
PubDate: 2022-08-01

• Investigation of a Near-Perfect Quad-Band Polarization-Insensitive
Metamaterial Absorber Based on Dual-T Circular Shaped Resonator Array
Designed on a Silicon Substrate for C-, X- and Ku-bands Applications

Abstract: Multi-band metamaterial absorbers (MMAs) are increasingly becoming main devices for many electrical systems. Optimizing the electromagnetic qualities of this type of absorber in the microwave regime is a relatively complex operation. In this paper a quad-band metamaterial absorber is provided for applications covering the microwave C-, X- and Ku- frequency bands. The proposed MMA is based on $$\left(8\times 8\right)$$ array basic cells. Each cell is formed by a split-ring metamaterial resonator (SRR), the chosen shape for the SRR is the circular dual-T (DT-SRR) interlinked with the rectangular ring. The DT-SRR is etched on the upper side of the Silicon substrate with relative electrical permittivity of 11.7. On the bottom side of the same substrate, a ground plane for full copper surface is printed to prevent transmission. The basic cell has the electrical dimensions of the order of $$\left({0.385 \lambda }_{0}\times 0.385{\lambda }_{0}\times 0.032{ \lambda }_{0}\right)$$ where $${\lambda }_{0}$$ is calculated at the lowest operating frequency of 6.43 GHz in the C-band. The electromagnetic qualities of our MMA are expired by the behavior of each basic cell which represents a left hand medium and a negative permeability $$\left(\mu <0\right)$$ for magnetic resonances at the frequencies 6.43, 9.10, 11.86 and 14.67 GHz. The obtained results simulations performed by the High-Frequency Structure Simulator (HFSS) computer show an insensitive-polarization dual-band behavior for our proposed MMA. The spectral responses of the proposed absorber cover the C-, X- and Ku-bands for important absorption coefficients of the order of 89.40, 99.66, 99.10 and 95.22%.
PubDate: 2022-08-01

• An Empirical Model for Bulk Electron Mobility in Si at Cryogenic
Temperatures

Abstract: In this paper, we present an empirical model for the bulk electron mobility in Si as a function of doping and temperature, down to the cryogenic range. With regard to lattice scattering, we have proposed an empirical model for the lattice dilation energy as a function of doping, using the data extracted from experimental results of bulk electron mobility at higher temperatures and low doping levels. We have also developed a new model for the ionized impurity scattering time using a novel approach of combining the scattering cross-section and the carrier velocity into a single variable. Finally, the Matthiessen’s rule was applied in order to obtain the net mobility. The results showed an excellent match with the experimental data reported in the literature over a wide range of temperature (20–400 K). Also, when compared to the results of some other classic models, with respect to the same set of experimental data, our results showed a much superior match, particularly in the cryogenic range. Finally, this model can be integrated easily to any of the empirical surface carrier mobility models for MOSFETs.
PubDate: 2022-07-30

• Experimental investigations on silicon carbide mixed electric discharge
machining

Abstract: In this study, silicon carbide mixed electrical discharge machining (SCMEDM) process has been developed and later on modelled also using an artificial neural network (ANN) based technique as well as response surface methodology (RSM). Experiments were conducted with Al LM-25/SiC metal matrix composites as per Box Behnken design (BBD). Discharge current, pulse-on-time, servo-voltage, powder concentration, tool material and varying reinforcement levels were considered as machining input parameters. Material removal rate, tool wear rate and surface roughness were taken to be the response parameters. Analysis of variance (ANOVA) method was used to investigate the significant effect of parameters on the response measures. The experimental data was trained using a back-propagation ANN technique. Research shows that the influence of current, pulse length and tool material on the machining characteristics of Al LM-25 MMCs is significant. Surrogated models were also developed for proposed process using RSM. However, the accuracy of ANN models was found to be better than that of RSM models.
PubDate: 2022-07-30

• Critical Examination of the Role of Silica Nanoparticle Dispersions in
Heat Transfer Fluid for Solar Applications

Abstract: Silica nanoparticles are eco-friendly with high heat transfer potential due to their low-cost synthesis, abundant natural resources, and mass production. Silica nanoparticles with advantages such as biocompatibility, ease-of-functionalization, and large surface area are widely employed in solar applications. Silica nanoparticles possess excellent properties such as good photoconductivity, ideal thermal expansion, high corrosion resistance, and long-term durability, which improve the system's overall efficiency. Dimethyldichlorosilane was employed to prepare silica nanoparticles into hydrophobic nanoparticles. The titration method computed the hydroxyl number of silica nanoparticles and reduced it after modification. The novelty of this work is to enhance the overall efficiency of the solar water heater by adding silica nanoparticles in heat transfer fluid owing to its higher thermal stability, heat resistance and improved structural properties of the nanoparticle. This work reveals a detailed study on the effect of silica nanoparticles on the performance parameters of the solar water heater. Silicon nanoparticles are dispersed with water using NaOH for pH adjustments and Cetyl Triammonium Bromide (CTAB) (1% by wt) as the dispersant to accelerate the vaporization and heating of the medium by local nanoscale heating. This study proposes that incorporating silica nanoparticles at different mass fractions shall improve the s overall efficiency of solar collectors. Silica nanoparticles are dispersed into water with and without using surfactant inside the absorber riser tubes for different mass fractions. The efficiency of the solar flat plate collector is calculated using the ASHRAE method. A collector of the area of 0.5 m2 of 25 LPD has been envisioned and made up with necessities to insert T-type thermocouples to study the temperature distribution. The weight fractions used are 0.2%, 0.4%, and 0.8%, and the experimental results showed an improved heat transfer was pragmatic in the collector using nanoparticles. The efficiency of the solar collector is improved by 2.5, 5.1 and 8.4% by adding Silicon dioxide nanoparticles at 0.2%, 0.4%, and 0.8% weight fractions, respectively. This study concludes that silicon oxide possesses high heat transfer potential and shall be employed in thermal systems.
PubDate: 2022-07-30

• Recent Progress on Sensitivity Analysis of Schottky Field Effect
transistor Based Biosensors

Abstract: In this review, we explored the modern development of schottky field effect transistor (SK FET) structures and the improvement of sensitivity of nanowire sensors using dielectric modulation. Here, the recent developments compared with the conventional schottky FET sensor, and modified conventional configuration have improved sensitivity and faster responses controlled by dielectric modulation and changing the barrier height. The change in sensitivity- with the current optimization has been considered for dissimilar gate, and drain voltage. The dielectric modulation can advance the finding limits, sensitivity, and reaction time of the novel structures in dissimilar applications, such as U-V finding, gas and chemical/ biosensing. In addition, the efficiency and doped channel have been deliberately studied under dissimilar biomolecule model specifications. This article reviews a recent study on emerging future generation SK FET biosensors with their sensitivity performance and the effect of their metal and channel contact is presented.
PubDate: 2022-07-29

• Beneficial role of exogenous silicon on yield, antioxidant systems,
osmoregulation and oxidative stress in fenugreek (Trigonella
foenum-graecum L.) under salinity stress

Abstract: Purpose In the Earth’s crust, silicon (Si) is the most abundant element after oxygen, while, under salt stress, its role in the tolerance of aromatic and medicinal plants (AMPs) is not yet detailed. For this reason, in this study we evaluated the effect of exogenous Si on some tolerance-related parameters in salt-stressed fenugreek, as an important AMP. Methods 3 mM of exogenous Si was applied to assess its impact on plant biomass and on some tolerance-related parameters in fenugreek (Trigonella foenum-graecum L.) grown under 150 mM NaCl stress. Results Results showed that salinity reduced growth parameters, relative water content, photosystem II efficiency, stomatal conductance and K+ and Ca2+ contents, while it increased the Na+ content, which could explain the obtained reduction in fenugreek growth and yield. However, Si supply reversed the depressive effects of salinity and improved fenugreek growth and yield. Adding exogenous Si also caused a significant reduction in Na+ content and increased K+ and Ca2+ concentrations. The content of malonyldialdehyd and hydrogen peroxide and the level of electrolyte leakage were significantly increased in salt-stressed fenugreek, while were significantly decreased after Si supplementation. The reduction in oxidative stress markers in Si-treated plants was correlated with a significant increase in both enzymatic and non-enzymatic antioxidant systems and an important accumulation of compatible solutes. Conclusion Therefore, exogenous Si was directly involved in the central defensive mechanisms to enhance salt tolerance of fenugreek, thus its application could be a promoting strategy to alleviate the damages of salinity on fenugreek growth and yield.
PubDate: 2022-07-29

• Improving the Mechanical and Wear Properties of Mg–Mg2Si In-Situ
Composite via Hybrid SiCp and Hot Working

Abstract: Numerous investigations have been performed on Mg/SiCp or Mg-Si systems; however, there is a shortage of research papers about Mg-Mg2Si-SiCp in the literature. Therefore, the structural evolution, tensile performance, and wear behavior of the Mg-Mg2Si-xSiC (x = 0, 1, 3, and 5 wt.%) hybrid composites were investigated. SiC particles (15 µm) were inserted into the Mg-Mg2Si in-situ composite using a stir casting system to form α-Mg, eutectic structure, primary Mg2Si, and SiC particles in the microstructure. Although SiCp addition reduced the grain size of the Mg-Mg2Si in-situ composite, no remarkable enhancement was found on ultimate tensile strength (UTS) in the as-cast state. On the other hand, by adding SiCp, yield stress (YS) was improved by decreasing the grain size due to grain refinement and particle strengthening mechanisms. The usage of hot extrusion led to structural refinement and uniform structures with less SiCp agglomeration. The optimum percentage of SiCp was 3 wt.% which diminished the grain size from ~ 153 µm to ~ 5 µm and developed the UTS values from 140.7 MPa to 246.2 MPa for the as-cast and hot extruded composites, respectively. Also, YS values met an increasing trend, from 146.5 to 190.3 MPa, than that of UTS in the extruded state. According to the Hall–Petch equation, the essential strengthening mechanism was grain refinement with about 73% effectiveness. Moreover, the fracture behavior of the composite shifted to a ductile form by applying the extrusion process, which revealed itself in the form of dimples. Wear analyses exhibited that the addition of SiCp and extrusion improved the wear properties, and the abrasion, adhesion, and the oxidation mechanisms played essential roles in the composites’ wear behavior.
PubDate: 2022-07-29

• Development and Experimental Study of Milling Electrochemical Spark
Micromachining (M-ECSMM) of Silicon

Abstract: Milling Electrochemical Spark Micromachining (M-ECSMM) is hybrid micromachining process which is used to create microfeatures in non-conducting materials. Silicon is one of the abundantly used material in microelectronics and micro-industry as base material for developing the user end products. In present paper, authors attempt to create the microchannels using M-ECSMM in the silicon wafer using tungsten carbide microtool (500 µm) in the presence of a hybrid electrolyte (NaOH + KOH). One-factor-at-a-time (OFAT) approach has been used to study the variation of material removal rate (MRR) and surface roughness (Ra) with change in parameters such as voltage, pulse on-time, electrolyte concentration, and rpm in multipass micromilling. It has been observed in experimentation that micromilling cannot be carried out on higher speed for silicon workpiece because tool stick around the bottom causing plastic adhesion on the workpiece. Similarly, MRR rises with increase in value of voltage above critical voltage and maximum roughness is achieved at 5.5 M of electrolyte. The experiments result for silicon are compared with machining of borosilicate glass coverslip on same parameters and similar results are seen where glass develops cracks or breaks at higher rpm.
PubDate: 2022-07-28

• Novel (Super)Hard SiCN from Crystal Chemistry and First Principles

Abstract: The purpose of this work is to predict the existence of novel equiatomic SiCN based on tetragonal C6 structure the elementary building unit being the 1,4 cyclohexadiene molecule comprising both tetrahedral (sp3) and trigonal (sp2) carbons. From crystal chemistry rationale the structural transformations of C6 to SiC2 and then to SiCN ternary phase were fully relaxed to the ground states using first principles DFT-based calculation. Like early proposed C6 and SiC2, SiCN was found bonding and structurally stable from the elastic properties on one hand, and dynamically stable from the phonons, on the other hand. The Vickers hardness of SiCN is higher than that of cubic silicon carbide, a conventional superabrasive, whereas hardness of tetragonal SiC2 is slightly lower. Besides the abrasive properties, the electronic band structure indicates metal-like behavior of SiCN thus suggesting the potential for heat dissipation in operating conditions, oppositely to insulating SiC.
PubDate: 2022-07-28

• Effects of Temperature and Si3N4 Diluent on Nitriding of Diamond Wire
Silicon Cutting Waste

Abstract: The effects of temperature and Si3N4 diluent on nitriding of diamond wire silicon cutting waste were studied in detail. The phase contents and microstructures of nitriding products were detected using X-ray diffraction and scanning electron microscopy. Moreover, the thermogravimetric and differential thermal analysis were used to investigate weight changes and heat flow changes of the samples in the heating-up stage. The results suggested that during the nitriding of cutting waste, the Si3N4 diluent as heat acceptor can absorb the additional heat released from the reaction between silicon and nitrogen, hindering the formation of the liquid phase, thereby improving the overall conversion and promoting the formation of α-Si3N4. It was also revealed that high temperatures can promote the formation of β-Si3N4. This is because α-Si3N4 is a low-temperature metastable phase and β-Si3N4 is a high-temperature stable phase, α phase can be transformed to β phase at high temperatures. Besides, nitriding mechanisms and effects of temperature and Si3N4 diluent on nitriding of the cutting waste were discussed.
PubDate: 2022-07-28

• Deep Insight into the Noise Behavior of SiGe Source Based Epitaxial Layer
Tunnel Field Effect Transistor

Abstract: A detailed simulation-based investigation on the noise behavior of SiGe source-based Epitaxial layer Tunnel field effect transistor (SiGe source ETLTFET) and Silicon Synthetic Electric field TFET (Si-SETFET) in the presence of interface trap charges having Gaussian distribution is presented in this paper. The results demonstrated that the flicker and G-R noises dominate the noise characteristics at low frequencies, while diffusion noise is the major contributor at high frequencies for both devices. The drain current noise spectral density (Sid) behavior of SiGe source ETLTFET in the presence of trap shows a reduced value than Si-SETFET. The preceding argument is supported by the observation of normalised Sid (Sid/IDS2) vs Drain current (IDS). The value of net Sid for SiGe source ETLTFET is found to be ~10−26 A2/Hz till 1 MHz. Furthermore, noise analysis at various temperatures shows that noise in presence of trap charges has a greater influence at lower temperatures in the higher drain current region. The result also revealed that the the Sid vs. frequency variation is a decreasing function of the Ge mole fraction in SiGe source ETLTFET. A brief comparison of net Sid among some of the reported studies and this study has also been presented. SiGe source ETLTFET is found to be more noise immune over a wider frequency range in comparison to the state of the art devices.
PubDate: 2022-07-28

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