Authors:Arda Alara ULUDAĞ; Elif Özlem ARSLAN AYDOĞDU, Ayten KİMİRAN Abstract: Listeria monocytogenes that the most common human listeriosis agent is one of 21 species of the Listeria genera. In fact, the mortality rate of listeriosis is higher than that of the more common foodborne pathogens such as Vibrio species or Salmonella Enteritidis. This study was aimed to determine the L. monocytogenes contamination in different minced meat samples. In this study, 100 minced meat samples purchased from different butchers in 11 districts of Istanbul between December 2018 and November 2019 were examined for the presence of L. monocytogenes. Isolates were molecularly confirmed for the presence of the iap and hlyA gene regions. It was determined that 21 biochemically defined isolates were susceptible to tetracycline and ampicillin, while resistant to amoxicillin/clavulanic acid, penicillin, cefaclor, and vancomycin. In addition, it was determined that only 16 of these 21 isolates were L. monocytogenes in terms of iap and hlyA gene regions. L. monocytogenes incidence in minced meat sold in Istanbul is low (17%), we believe that these contamination rates indicate a significant risk to public health due to cross-contamination and raw consumption of minced meat. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Meryem YALÇINKAYA; Burak BİRGÖREN Abstract: The Weibull distribution has been widely used to model strength properties of brittle materials. Estimation of confidence intervals for Weibull shape parameter has been an important concern, since small sample sizes in materials science experiments bring about large intervals. Many methods have been proposed in the literature for constructing shorter intervals; the methods of maximum likelihood, least square, and Menon are among the most extensively studied methods. However, they all use an equal-tails approach. The pivotal quantities used for constructing confidence intervals have right-skewed and unimodal distributions, thus, they clearly do not produce the shortest intervals for a given confidence level in equal tail form. This study constructs the shortest confidence intervals for the three aforementioned methods and compares their performances by their equal-tails counterparts. To this end, a comprehensive simulation study has been conducted for the shape parameter values between 1 to 80 and the sample sizes between 3 to 20. The comparison criterion is chosen as the expected interval length. The results show that the shortest confidence intervals in each of three methods have yielded considerably narrower intervals. Further, the unknown parameter values are more centered in these intervals. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Abdallah YASSİN; Ebru GÜNİSTER Abstract: The processing parameters to disperse active filler within a polymer matrix to enhance the polymers’ properties should be selected carefully to achieve the best dispersion. In this research, Box-Behnken Design (BBD), an experimental design for response surface methodology (RSM), with three levels was used as a design of experiment (DOE) to analyze the effect of processing parameters on the thermal and rheological properties of high-density polyethylene-organoclay (HDPE-OC) composites prepared by adding organoclay (OC) to high density polyethylene (HDPE) using melt blending method. HDPE-OC composites were characterized morphologically by SEM and XRD, and thermally by DSC and TGA, and tested rheologically. Investigated factors were filler amount, mixing temperature and screw speed. The evaluated responses were melting temperature, degradation temperature, storage modulus, and complex viscosity of HDPE-OC composites. The effect of each factor on the responses was determined through an analysis of variance (ANOVA). The obtained data was used to predict the responses by fitting into a second order equation with MINITAB software. Constructed models were verified using validation experiments therefore optimum melt blending processing parameters obtained as 1.5 wt.% of OC, mixing temperature of 183 °C, and screw speed of 77 rpm for HDPE-OC composites. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Akshaykumar NAREGALKAR; Subbulekshmi D Abstract: The ability to describe the nonlinear process dynamics is an essential feature of the Hammerstein model that paved more research and application studies in system identification and control. Using the Hammerstein model, this study shows an alternative approach to identify and control the highly nonlinear pH neutralization process. This Hammerstein model called Laguerre Least Square Support Vector Machines (LLSSVM) models the static nonlinearity with LSSVM and the linear part with Laguerre filter. The identified LLSSVM Hammerstein model performance evaluation with Mean Squared Error (MSE) and Variance Accounted For (VAF) is better than the Linear Laguerre model. We apply the identified LLSSVM Hammerstein model to implement a Nonlinear Model Predictive Controller (NMPC) to control the pH neutralization process. Then evaluated NMPC performance in terms of Integral Squared Error (ISE), Integral Absolute Error (IAE), and Total Variation (TV) and Control Effort (CE) parameters to verify its effectiveness in set-point tracking and disturbance rejection problems. The comparison of the NMPC with the Linear Laguerre Model-based Predictive Controller (LMPC) shows better performance of the NMPC than the LMPC. Results show that the LLSSVM Hammerstein model replicates the pH neutralization process well than the Linear Laguerre model. Also, the identified LLSSVM Hammerstein model provides an efficient NMPC than the LMPC for the pH neutralization process. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Orhan ACAR; Rabia SANKAZAN, Özcan YALÇINKAYA Abstract: Cadmium, tin, iron, copper, and zinc in tea, rice, and liver samples, and standard reference materials (IRMM 804 Rice Flour, GBW 10010 Rice, Bovine Liver1577c and GBW 07605 Tea Leaves) were determined by using electrothermal and flame atomic absorption spectrometries. Cd and Sn in sample solutions were determined with electrothermal atomic absorption spectrometry by using palladium (Pd) as a matrix modifier. Pyrolysis and atomization temperatures and pyrolysis times of Cd and Sn in sample solutions were optimized in the absence or presence of Pd. Pyrolysis temperatures of Cd and Sn found in the presence of Pd were 800°C and 1200°C, respectively. Iron, Cu, and Zn in samples were determined by flame atomic absorption spectrometry. The accuracy and precision of the method were validated by determining elements in standard reference materials. Limits of detection for Sn, Cd, Fe, Cu, and Zn were found as 0.66, 0.26, 2.0, 1.9, and 1.2 μg/L, respectively. Concentrations of elements found in samples were compared with maximum values reported by World Health Organization (WHO) and other studies. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Mostefa LEFAHAL; El-hani MAKHLOUFI, Radia AYAD, Ahlem BOUSSETLA, Mohamed ELHATTAB, Merve KESKİN, Salah AKKAL Abstract: The interest of using natural ingredients in cosmetic products has getting increased specially developing in new photoprotective formulations. In this study, it was undertaken to evaluate the cosmeceutical potential of the aerial parts of the species Bunium alpinum Waldst. & Kit (Apiaceae family) growing Algeria, by assessing their photoprotective and antioxidant effects. For this purpose, the total antioxidant capacity and activity were determined by using phosphomolybdenum and DPPH· radical scavenging methods. The in vitro photoprotective effect against UV-B radiations was determined according to the Sun Protection Factor (SPF) by using UV spectrophotometer at the range between 290 and 320 nm and Mansur equation. It was clear that among the tested extract, content of phenolic compounds and flavonoids of butanolic extract (Ba-BuOH) had higher than other extracts and it possessed strong antioxidant activity in DPPH· radical scavenging (20.65±0.017 mg VCE/g) and total antioxidant activity (196.69±4.08 mg VCE/g) assays. Similarly, its major compound Apigenin-7-O-rutinoside exhibited high photoprotective activity in UVB and UVA range and the SPF values were (14.70±0.11 and 32.80±0.5, respectively). The results gathered from our work reveal the using possibility of this extract and its major as antioxidant and sunscreening agent in cosmetic formulations. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Hatice Mehtap BULUKLU; Filiz BAL KOÇYİĞİT, Ercan KÖSE Abstract: Experimental criteria for sound insulation material recommendation and design have an important share in indoor acoustic control. Among these criteria, laboratories with devices such as impedance tubes, alpha cabins and reverberation rooms used to measure and analyze parameters such as sound transmission loss and sound absorption coefficient have been investigated. In literature, it has been observed that there are studies on acoustic materials and the tests applied to these materials, but the application is more limited. According to research data, an Alpha Cabin model system design that can be used to develop new types of acoustic sound materials has been proposed. In addition to the fact that a large number of experimental measurements can be performed at lower costs using the designed Alpha Cabin model system, many tests can be performed easily for different material designs in a very short time. To perform these tests, the Alpha Cabin system has been designed based on noise and sound insulation. For example, floating flooring, ribbed connection, and so on. Afterward, different insulation materials were used for insulation purposes and standards were achieved. The Alpha Cabin test system, which was designed and developed, overlaps the experimental and theoretical data for 500, 2000, and 4000 Hz when compared with the values of 29.1 dB for 500 Hz, 38.6 dB for 2000 Hz, and 49 dB for 4000 Hz measured in the Acoustic Facade Panel Test Room, and it has been observed that it can be used in the development of new sound insulation materials. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Sangeeta SHEKHAWAT; Sanjay Kumar SİNGH, Sudhanshu SİNGH, Ashutosh TRİPATHİ Abstract: Wearable electronics have gained opportunities in recent years, and the last decade has been evidence of this growth in Wireless Body Area Networks (WBAN). They meet the criteria for personalizing healthcare, communication, patient monitoring, tracking, and rescue operations. The main challenge for the WBAN is to handle the radiator's coupling with the human body. An artificially generated Electromagnetic Band Gap (EBG) structure was designed and used in this work to improve the performance of a microstrip patch antenna. A jeans-based microstrip patch antenna with an EBG surface demonstrated to enhance the performance for 5.5 GHz WiMAX application. The use of an EBG surface increases return loss by 20%, with a reasonable bandwidth of 0.528 GHz (5.271 GHz to 5.749 GHz) at the resonance frequency of 5.5 GHz. The EBG surface improved the Voltage Standing Wave Ratio (VSWR) by 60%. A three-layered human body tissue model is also used for on-body measurements to determine the performance of an EBG-based antenna. The presence of human tissues generally reduces performance and shifts the resonance, but the shifting in this work with the simplified EBG structure and adequate gain and VSWR is only 2.6 percent. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Mahya GHOUCHANİ; Mohammad TAJİ, Amir Hassan YAGHOUBİ ROSHAN Abstract: The purpose of this study is to investigate the concept of light and its interpretation in different styles of Iranian-Islamic architecture. By distinguishing between the content and the physical evaluation of historical periods, one can find a way to properly use different patterns in contemporary mosques. The present study has been conducted using descriptive-analytical method and consists of three stages. First, the role of light in the mosque is investigated, then qualitative and quantitative data have been classified. For this purpose, the ergonomic lighting index questionnaire and its analyzer software (ELI-calculator) have been used. Finally, data have been examined and analyzed by SPSS software. The results of the research show that two criteria of "quality of vision" and "visual comfort" have been of great importance in all periods and styles of Iranian-Islamic mosques; but the architects of the historic mosques have paid more attention than contemporary mosque architects to the criteria of "prospect" and "vitality in the environment" and this difference is statistically significant. Therefore, how the shape of the openings and their location and the way light is applied affects the satisfaction level of the person during worship. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Durmuş ALBAYRAK; Nese DERNEK Abstract: In this paper, Parseval-Goldstein type theorems involving the G ̃n-integral transform which is modified from G_2n-integral transform [7] and the -integral transform [8] are examined. Then, theorems in this paper are shown to yield a number of new identities involving several well-known integral transforms. Using these theorems and their corollaries, a number of interesting infinite integrals of elementary and special functions are presented. Generalizations of Riemann-Liouville and Weyl fractional integral operators are also defined. Some theorems relating generalized Laplace transform, generalized Widder Potential transform, generalized Hankel transform and generalized Bessel transform are obtained. Some illustrative examples are given as applications of these theorems and their results. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Ziya MERDAN; Fadime Irmak BALMUMCU Abstract: The electronic, magnetic and structural properties of Pd2FeTl compound were investigated in this study. The Vienna Simulation Package program was used to perform calculations, based on DFT and Generalized Gradient Approximation. The lattice parameter of 6.360A0 and its magnetic moment value of 3.063μB/f.u. are calculated. The values for the magnetic moment and lattice parameter were found to be in conformity with those in the literature. As electronic properties and band structures were calculated, also the density of state curves compatible with the band structures were drawn. There is no band gap between the energy bands in terms of Pd2FeTl compound and according to the calculations, this compound has a metallic structure. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Engin ÖZKAN; Mine UYSAL Abstract: In this study, we present higher order Jacobsthal numbers. Then we define higher order Jacobsthal quaternions by using higher order Jacobsthal numbers. We give the concept of the norm and conjugate for these quaternions. We express and prove some propositions related to these quaternions. Also, we find the recurrence relation, the Binet formula and the generating function for these quaternions. Finally, we calculate Cassini, Catalan, Vajda and d’Ocagne identities for higher order Jacobsthal quaternions. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Nur SİPAHİOĞLU; Gülen ÇAĞDAŞ Abstract: The speed at which cities are growing and developing today cannot be disregarded. Human activities and natural causes are both contributors to urban growth. The relationship between these factors is complex and the complexity makes it difficult for the human mind alone to understand cities. A model that helps reveal the complexity is needed for urban studies. Main objective of this study is to understand the effects of urban planning strategies on the future of the city by utilizing a Cellular Automata and Artificial Neural Networks based simulation model. Driving factors of urban growth according to development scenarios were used in the simulation process. Six different development scenarios were formulated according to the strategic plan of Izmir. Land use and driving factor data used in simulating scenarios were acquired from EarthExplorer and OpenStreetMap databases, and produced in QGIS. Future Land Use Simulation Model (FLUS) based on Cellular Automata (CA) and Artificial Neural Networks (ANN) was used. The results were assessed both by using FRAGSTATS which helped calculate fractal dimensions and visual analysis. Fractal dimension results of each scenario showed that the simulation model respected the overall urban complexity. A closer look at each scenario indicated the diverse local growth possibilities for different scenarios. The results show that urban simulation models when used as decision support tools promise a more inclusive and explicit planning process. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Galip Orkun ARICAN; Nursel AKÇAM Abstract: In this article, we demonstrate a low-cost 7.25-7.75 GHz two-stage low noise amplifier with sub-1-dB noise figure for satellite communication applications. The microstrip technology on Rogers RT5880 substrate with the dielectric constant of 2.2 and thickness of 0.508 mm were utilized to develop a low noise amplifier. The printed-circuit-board technology offers a variety of profits such as being low-cost, lighter-weight and re-configurability after the manufacturing process make this technology charming for satellite communication systems for both commercial and military applications. Since the monolithic microwave integrate circuit technology provide much smaller sized circuits and high electrical performance especially at the millimeter-wave frequencies, the printed microstrip technology can be a significant rival to integrated-circuit technology with its proven reliability, easier, cheaper and faster manufacturing process, compactible electrical performance in X-band applications. Moreover, the proposed amplifier was developed with utilizing California Eastern Laboratories’ CE3512K2 transistor on Rogers-RT5880 and surface mount devices were utilized in the matching networks to reduce the size. In addition, the source-generation and interstage matching topologies were implemented to simplify the matching complexity to enhance the noise and gain. The prototype was manufactured with utilizing LPKF prototyping machine. The developed LNA exhibits a measured gain of 23.5±0.5 dB with the noise figure of less than 0.9 dB and input/output return loss better than 11.5 dB in the operating frequency bandwidth. Furthermore, the developed amplifier has a measured carrier to interference of -59 dBc and P1dB of 13 dBm at the center frequency while consuming a total DC power of 50 mW. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Samar TAHA; Firas ISMAİL, Sivadass THİRUCHELVAM Abstract: Gas turbines efficiently produce high amounts of electrical power hence they have been widely deployed as dependable power generators. It has been detected that the performance of gas turbines is a function of plenty of operational parameters and environmental variables. The impacts of those variables on the said performance can be mitigated using powerful monitoring techniques. Thus, extra maintenance costs, component defect costs, and manpower costs can be illuminated. This paper has enlisted the factors impacting gas turbine efficiency. It has also reviewed multiple monitoring solutions for the said impacting factors, It has been concluded that all types of sensors have ignored errors in their work, which may exacerbate the problems of malfunctions in gas turbines due to the critical environment in which they operate (heat, fumes, etc.); however, the machine learning-based monitoring systems excel in addressing such problems. The most cost-effective and accurate monitoring task can be achieved by using machine learning and deep learning tools. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Gulshan MAJİD; Ahmad AKHTER Abstract: An innovative model titled as Exponentiated stretched exponential distribution is introduced. The main statistical properties of subject distribution are derived and special models are particularized. The most general technique of maximum likelihood estimation is focused to obtain the parameter estimates of new innovative model. A simulation study is presented to evaluate the behavior of the proposed estimators. Asymptotic confidence intervals for unknown parameters of new model are also suggested. The characterization of model is also checked. The competency of the subject distribution is demonstrated by fitting four real data sets through evaluation criteria. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Bipin Kumar RAİ Abstract: In daily life, vitamins fruits and vegetables play a very important role in human life. The farmer produces grains or vegetables in huge quantities. Due to lack of storage problem farmer suffers. It is necessary to store all these things in a special warehouse. Thus, improper storage of grains or fruits is essential to meet the increasing demands. Storage time and fruit quality are greatly influenced by storage environmental factors. Therefore, it is important for the fruit storage environment to perform multi-parameter monitoring and analyze the collected parameters and then regulate and control. The quality of grains and other perishable goods kept in a warehouse usually deteriorates due to lack of monitoring and proper maintenance of their required suitable conditions in such a large area. The proposed methodology deals with the storage of grains, fruits, etc., and to identify their temperature and humidity patterns so that they will not be degraded. Establishing the environment in relation to the nature of the crop so as to determine an optimum threshold with an appropriate pattern of monitoring and change. The main goal of this research article is to provide solutions to prevent rotting of grains and fruits in the storage area. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Selma AKÇAY Abstract: This study numerically examined the impacts of central winglets and Al2O3-water nanofluid on the thermo-hydraulic performance in a zigzag channel. The analyzes based on Computational Fluid Dynamic (CFD) using the SIMPLE algorithm are actualized for nanofluid flow in Reynolds numbers (Re) varying between 200 and 1200. The volume fraction of nanoparticle (φ) is changed from 1% to 5 %. The upper and lower zigzag surfaces are kept at Tw = 350 K constant temperature. The results are given in terms of thermal improvement (η), dimensionless friction factor (Γ), and thermo-hydraulic performance (THP). In addition, the work is compared with the zigzag channel without winglet for the base fluid. The temperature and velocity distributions are obtained for the zigzag channel with and without winglet at different Reynolds numbers. The results show that the nanofluid and winglets contribute considerably to the enhancement of heat transfer, but the friction factor slightly increases. The heat transfer improves with increasing inlet velocity and particle volume fraction. The highest thermo-hydraulic performance is obtained as approximately 2.12 for Re = 400 and φ = 0.05. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Bensaad ABDELLAH; Garadi AHMED, Beloufa ABBES, Bensaad ZOUAOUİ Abstract: A new structure code for Spectral Amplitude Coding Optical Code Division Multiple Access (SAC–OCDMA) system with zero cross-correlation (ZCC) is presented in this paper. The principle idea of this method is based on the use of Zech logarithms in the construction of the code sequences to ensure orthogonality and compare their performances with previously reported codes. The maximum cross-correlation of this code is zero signifying that Multi-Access Interference (MAI) and Phase-Induced intensity noise (PIIN) effects are eliminated thus the system performances are improved. The BER simulation results against the total number of active users show a significant improvement in the performance of the proposed code over preceding reported codes. The system can accommodate more than 90 simultaneous users compared to other codes at a bit error rate of 10^(-9). Furthermore, the construction method offers good flexibility in the choice of the number of users, the weight, and the code length. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Manoj GUPTA Abstract: Production systems have been growing exponentially in size in recent decades. One of the problems in the manufacturing system is that a need of effective and efficient materials transportation between the workstations. Auto-mated guided vehicles (AGV’s) can provide a satisfactory solution to this issue. Because of this, AGV’s is a one of the most important material handling tool used in flexible manufacturing system (FMS). The designing, scheduling and routing of the AGV’s are the key issues for the reason that performance of AVG’s in flexible manufacturing system depends on these parameters. The failure of AGVs may significantly impact the operation and efficiency of the entire system, and it is a critical issue. In this paper the aims to answer How the reliability of individual AGVs in the system assessed' , and How AGVs affects the performance of the whole FMS system'. It was also discussed that optimizing techniques to improve the performance of AGV in FMS. This paper discussed the details studies of approaches and optimization techniques used for optimizing AGV’s in FMS including design and their control. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Waggas GALIB; Reaam Abd AL-SAJJAD, Şahsene ALTINKAYA Abstract: In this article, we aim to describe a new operator J_(s,a,μ)^(δ,λ) via convolution. Moreover, we aim to present a new subclass C_Σm (τ;β) related to m-fold symmetric bi-univalent functions in the open unit disk Θ={z∈C∶ z ˂ 1 }. Finally, an estimate related to the Hankel determinant for functions in C_Σm (τ;β) are given. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Masoud MOSAYEBİ; Pouya MALLAHİ KOLAHİ Abstract: The design of the mobile robot path is important when obstacles are present in the environment. In the present study, the theory of optimal control for path design and obstacle avoidance via simultaneous minimization of the time and kinetic energy is proposed. Nonlinear equations of robot motion without simplification are considered in optimum control problems, and in order to prevent collisions, the potential functions are utilized. In the next phase, the cost function is proposed that includes velocity inputs, time, and the potential function for obstacle avoidance, in which the nonlinear equation of the motion of the mobile robot is deemed as a constraint. The final equations are numerically solved, and the capability and effectiveness of the presented method will be presented via different simulations on the mobile robot. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Berkay KARACOR; Mustafa ÖZCANLI Abstract: In recent years, various new and practical products have emerged thanks to rapidly developing science and technology to meet human needs and expectations. A variety of these products are new materials known as composites. The use of composites is also increasing, from the aircraft industry to the automobile industry, to other areas such as sports equipment, infrastructures. The goal of this research is to present a hybrid composite material that can be retainable and does not harm the environment that can be used in the automobile industry. This goal has been tried to be achieved by using natural fiber (flax fabric) reinforced glass fibers in different weights (86 gr/m² and 100 gr/m²). The vacuum assisted resin transfer molding (VARTM) system was used to fabricate the composite samples. Composite products produced during the study were tested with regard to mechanical (tensile strength, bending strength), hardness, and morphological (scanning electron microscopy). The results indicate that the tensile strength value of hybrid composites is 2.5 times and 1.7 times higher than that of homogeneous composites and flexural test results also 78% and 23% enhancement compared to single fiber composites. According to the hardness test measurement of hybrid composites, it was found that the hardness value changed with an increase of 14% and 33% compared to the homogeneous composite. Scanning Electron microscopy (SEM) analysis images also coincide with mechanical analysis results. The hybrid composites produced in the study have become a favorable option in diverse areas of use in the automotive industry, considering human health and environmental factors. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Nursel GÜL; Nuri YİĞİT, Fulya SAYGILI YİĞİT, Eda YAZICI ÖZÇELİK, Hakan ESKİZENGİN Abstract: Diflubenzuron is a commonly used larvicide/biocidal substance. The present study aimed to reveal the effects of diflubenzuron on Acetylcholinesterase (AChE) enzymatic activity and liver histopathology of a mammalian species (rats). The animals fed with various doses of diflubenzuron and the liver tissues of rats were taken on the 10th, 20th, 25th, 45th days and sixth month. AChE activity of liver was measured by spectrophotometer. Tissues were embedded in Araldite 502 (Sigma), took ultrathin sections, and examined under a 100 CX II Transmission Electron Microscope. AChE activity in the chronic dose of diflubenzuron group was like that in the control group. The enzymatic activity in the subacute dose was found to be significantly different from the control group. After subacute dose exposure was terminated, the AChE activity was still lower on the 45th day compared with the control group. Chronic and subacute doses caused adverse effects to liver tissues, such as numerous mitochondria, abnormally structured nuclei in the hepatocytes and many lipid droplets in the sinusoids of the liver ultrastructure. After the subacute dose was terminated, liver damage was still observed on the 20th and 25th days, but the liver tissue was partly regenerated on the 45th day. Cellular damage might recover after 45 days, but AChE activity probably takes more time to reach a normal level. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Neelam SHAHİ; Sujit Kumar SHAH, Amar Prasad YADAV, Ajaya BHATTARAİ Abstract: The interaction between methyl red (azo dye) and cetylpyridinium chloride (cationic surfactant) in the methanol-water system were studied using a spectrophotometric technique. Variable parameters like constant dye concentration and its structure, surfactant concentration, pH, absorbance, and solvent composition were studied. Using the UV-Vis technique, critical micelle concentrations (CMCs) of cetylpyridinium chloride were measured with methyl red. The spectral data were analyzed and determined the differential absorbance, binding and partition constants, partition coefficient, the Gibbs free energy of binding and partition in mixed solvent media (0.1, 0.2, 0.3, 0.4 volume fraction (v.f.)s of methanol, respectively). PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Erol YÜCEL; Serpil EROL Abstract: This research focused on higher education graduates in Germany and Turkey on all fields of education, especially engineering programs in terms of all education levels and gender. The study has provided situational awareness in general on all fields of education, levels of education and gender, but on the “Engineering, manufacturing and construction” field in detail. In the research, many important findings are identified. Turkey’s ED7 (Master’s or equivalent level) and ED8 (Doctoral or equivalent level) graduate numbers and ratios are significantly lower than Germany when compared to the ED6 level. The research also revealed us that the graduation ratios of ED6 (Bachelor’s or equivalent level) and ED7 among female engineers in Germany are close to each other, indicating that female engineers in Germany are more likely to hold a master's degree after undergraduate education. Among these findings, the most important finding is; while the gender ratio of higher education graduates in Germany at all education levels is almost equal between male and female students, this ratio has started to increase in favor of female graduates in Turkey. This situation developed differently among graduates of engineering programs. While engineering graduates in Germany had a fixed ratio of approximately 80.5% male and 19.5% female graduates between 2014 and 2019. In Turkey, this ratio is improving in favor of female graduates from 32.8% in 2014 to 34.9% in 2019. In this research, it is concluded that the higher education intelligence needs to be top priority for higher education officials. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Farzaneh BAGHERİ; Hasan KOMURCUGİL Abstract: This paper presents an adaptive sliding mode control (SMC) method with a variable boundary layer for single-phase voltage source inverters. This strategy offers a very simple sliding function without any derivative term while preserving unique characteristics of the sliding mode control like fast dynamic response and robustness against parameter variations while also possessing the variable boundary layer method to reject the chattering phenomena. Chattering excites the high frequencies in the system and leads to inaccuracy and instability. It is shown that despite the conventinal approches, the proposed variable boundary layer method can both alleviate the chattering and generating the minimum steady state error. Owing to the adaptive nature of the suggested control approach which adjusts the thickness of the boundary layer, the whole mechanism can be controlled successfully under unpredictable parameter variations. The accomplishment of the suggested strategy is investigated by simulations in MATLAB/Simulink. The outcomes are compared with the outcomes obtained without boundary layer, with constant boundary layer and super twisting sliding control methods. The comparison reveals that the proposed control technique outperforms the other control methods for the voltage source inverter. The results demonstrate that while the conventional, SMC with constant boundary layer and super twisting sliding control (STSMC) methods have 50% ,8% and 10% chattering over their control input respectively, the proposed method has less than 3% chattering over the control input. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Pei JU; Dongzhuang TİAN, Hongjie TİAN Abstract: In order to analyze the rock disintegration characteristics of special-shaped Polycrystalline Diamond Compact (PDC) cutters, numerical simulation and micro-drilling test on four kinds of special-shaped PDC cutters are carried out. Simulation results show that, the surface stress of each PDC cutter is quite different. For the dual-chamfer PDC cutter, the second chamfer can expand the stress on the cutting edge to a larger area; for the conical PDC cutter, the maximum stress is concentrated at the tip of the cone; for the ridged PDC cutter, the stress is distributed in a triangular fan shape from the lower edge of the cutting edge upward along the ridge, and for the triangular ridge PDC cutter, the stress is mainly distributed on the lowermost ridge. The conical PDC cutter has advantages in rock disintegration stability and efficiency, but it requires a higher weight on bit; the ridged PDC cutter has advantage in rock disintegration efficiency, but it tends to swing sideways when breaking rock; the dual-chamfer structure of PDC cutter is beneficial to extend the cutter’s life, but its rock disintegration efficiency is poor. Anchor bits with these special-shaped PDC cutters are produced, and electro-hydraulic micro-drilling test are carried out, the results of micro-drilling test and numerical simulation show the same law excluding conical PDC cutter. The research results can provide guidance for the application of special-shaped PDC cutters in drill bit. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Hemalatha K N; Sangeetha B G Abstract: Multiplication is the key crucial operation in realizing digital signal processing (DSP) functions. It is accomplished by using diverse multiplier architectures. Multiplication operation is furthermost basic and normally used action in the central processing unit (CPU). The multiplication operation is the most fundamental and commonly performed activity in the central processing unit (CPU). An efficient multiplier design should have a high speed, small area, and a low power consumption. Compact, efficient multipliers with minimal power dissipation are needed. The proposed paper provides a thorough inspection of multipliers such as the Array multiplier, Booth multiplier, column bypass multiplier, Baugh-Wooley multiplier, and Vedic multiplier based on their operational activities and working, as well as their benefits and limits. A comparison of these multipliers' performance parameters such as speed, area, power consumption, quantum cost, garbage generation and circuit complexity. PubDate: Wed, 01 Mar 2023 00:00:00 +030
Authors:Deniz MERDİN; Filiz ERSÖZ, Harun TAŞKIN Abstract: Changing market expectations and the increasing prevalence of the new technological trend in the world force businesses for digital transformation. However, the late realization of transformation opportunities may have devastating effects on businesses. As the first step of digital transformation, it is necessary to determine the status and deficiencies of businesses. Therefore, businesses need to make a comprehensive assessment with the digital maturity model. This study was conducted to provide businesses with an idea about the relevant digital transformation processes, to direct them toward the processes, and to support these activities when they are initiated. In the study, seven scales were developed, and the dimensions of the digital maturity model were formed. The dimensions of model were determined as strategy, customers, employees, process management, technology and data management, organizational culture, and innovation. This study aimed to examine the reliability and validity of the dimensions of the digital maturity model developed. In this context, the developed scales were applied to businesses in Turkey, and explanatory factor analysis (EFA) and validity analysis were performed. The scales were updated according to the analysis results. Moreover, the analysis results of the study were also used to specify the criteria of the model. The findings indicated that the developed scales were usable. It was purposed to provide researchers and businesses with significant opportunities since the model had a wide area of application and included environmental elements. PubDate: Wed, 01 Mar 2023 00:00:00 +030
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