Proton exchange membrane fuel cells (PEMFCs) consist of six main components: current collectors (CC), end plates (EP), bipolar plates (BPP), gas diffusion layers (GDL), gaskets, and membrane electrode assembly (MEA). PEMFC assembly or design parameters are critical for maximum performance, strength, and reliability. The cell's mechanical behavior should be known for optimum fuel cell assembly and design. Therefore, a three-dimensional finite element model of PEMFC with an active area of 100 cm² was developed, and the stress and deformation values in the cell components were calculated with Ansys Mechanical software. The response surface method (RSM) was applied to obtain optimum levels and analyze the effect of design parameters. For statistical analysis, bolt number, bolt hole diameter, and clamping torque were defined as three different independent design variables, and their individual-combined effects on stress and deformation, which were determined as response parameters, were analyzed. Therefore, the number of bolts, bolt hole diameter, and clamping torque ranges are 12-20, 4-6 mm, and 9-15 Nm, respectively. When the number of bolts is 12, the bolt hole diameter is 6 mm, the clamping torque is 9 Nm, the total minimum deformation is 0.063 mm, and the minimum stress on the membrane is 12.846 MPa. As a result of reducing the bolt hole diameter from 6 mm to 4 mm, the total deformation has increased by approximately 60.4%. With the increasing number of bolts, more homogeneous stress distributions were achieved, and the end plate's maximum stress increased by about 83.3%. The increase in clamping torque has caused a pressure increase of roughly 21 MPa on the membrane. The numerical and statistical findings of the study can be an important guide in evaluating the performance, durability and reliability of the PEMFC.

As a result of increasing population density, problems in residential areas have emerged in cities in recent years. With the development of technology, engineers have turned to the construction of taller buildings to meet the increasing demand. As a result, heat island formation becomes inevitable if there is not enough distance between buildings. In this study, it is aimed to numerically investigate the heat island formation and wind effects in buildings. The Ansys Cfx software program was used for the modeling process. Six different building configurations were analyzed to investigate heat island formation. Building heights and inter-building distances were varied for different aspect ratios. As a result of the study, more heat islands formed when the distance between buildings was smaller. As a result of the study, more heat island formation was observed in the first four cases (C1--C4). C5 and C6 were found to be the most suitable building sequences. drag coefficients (Cd) were obtained in the range of 1.35 to 1.65 for different building sequences. As a result of the cooling effects of the wind on the building, a decrease of 2 to 5 degrees in the average temperature of the building was observed. The average heat transfer coefficient is (68 W/mK) when only concrete is used in buildings. The best insulation was realized when glass wool was used.

In this study, the effects of hot-dip aluminizing (HDA) (90 sec at 725°C) and post-heat treatment on the microstructural and tribological properties of DP800 steel were investigated. After HDA treatment, one of the sample was left to cool in air (HDA-1) and the other one left to cool in air after being subjected to a heat treatment for 1 hour in an oven set at 300°C (HDA-2). Evolution in mechanical properties depending on the developments in the coating microstructure investigated in terms of hardness and wear behaviour. Characterization results show that heat treatment increases the hardness value of hot dip aluminized steel to 1100 HV values. Considering the wear ball volume and friction coefficients, the most advanced tribological properties were observed in the heat-treated HDA process (HDA-2).

As long as humanity exists, it will continue to produce waste. For a livable society, these wastes need to be collected and disposed of at regular intervals. The collection and disposal of these wastes involve many processes and can be quite costly. This study aims to optimize the journey of solid waste from generation to a disposal facility with minimum time and cost, and the solution of the Capacity-constrained Vehicle Routing Problem (CVRP) is used as an optimization technique in this study.A dynamic perspective was added to the capacitated CVRP by incorporating a decision mechanism that determines whether containers should be collected or not based on their predetermined fill levels. The Internet of Things methodology was utilized, and fill sensors were added to the containers. Genetic algorithms, one of the metaheuristic methods, were used in the algorithm's solution, which was implemented through a Python program. After testing the algorithm on a trial network, a specific location was selected. The chosen region is Gerzele Neighborhood in Denizli Province, and the TURKSTAT data pertaining to the neighborhood were used in the calculations. The coordinate data for the neighborhood and the locations of the containers were mapped, and transportation data was generated by integrating them into the Visum program. The collection process was carried out based on the fill levels of the containers using the sensors, and several scenarios were tested. It was determined that cost, distance traveled, and collection times for waste logistics could be reduced by 20-40% based on the obtained results.

This study addresses the tracking problem for robot arms with parametric uncertainties in the model, position measurements available, and no velocity measurements. A filtering technique based on position information is used to compensate for the unmeasured velocity information. A linear filter-based controller is designed to eliminate the controller's dependence on velocity measurements by utilizing adaptive neural networks for model uncertainties. The stability of the closed-loop system is guaranteed by the Lyapunov method. To demonstrate the performance of the proposed controller, numerical simulation results are generated using a two-degree-of-freedom robot arm model and compared comparatively with adaptive fuzzy logic method.

In the drilling process of printed circuit boards, achieving the operation with the least cost depends on the distance travelled by the drilling route. In this study, an integrated method is proposed to carry out the drilling process with the least cost and high speed. In the proposed method, the positions of electronic circuit elements to be placed on the printed circuit board are detected using image processing techniques on a two-dimensional circuit image. Annealing Simulation, Particle Swarm Optimization and Ant Colony Algorithms have been used to solve the travelling salesman problem, and their performances have been examined. When comparing the test results of the obtained models, it is observed that the Ant Colony Algorithm, at the same iteration values, provides solutions with significantly shorter route lengths compared to Simulated Annealing and Particle Swarm Optimization algorithms.

In this paper, a state and parameter observer, based on a novel extended Kalman filter (EKF), is designed to solve the parameter variations dependent estimation performance deterioration of induction motor (IM) drive systems. The proposed EKF based observer algorithm performs online estimation of the rotor mechanical speed, stator stationary axis component of the stator currents and rotor fluxes, stator resistance, rotor resistance, reciprocal of the total inertia of the system, and load torque including viscous friction term in a single EKF by using measured rotor mechanical speed and stator currents. Thus, frequency and temperature-dependent variations of the resistances are estimated to be updated in the observer, which leads to control performance enhancement of the IM drive. Moreover, to rise the dynamic performance of the observer, the load torque and reciprocal of the total inertia of the system which are mechanical parameters are also estimated. To verify the robustness of the IM drive and the estimation performance of the proposed observer, they have been tested under challenging scenarios including changes in parameters and speed reference. Moreover, the estimation performance of the proposed ninth order observer is compared with that of a sixth order EKF estimating the same electrical parameters by using directly measured speed. Ultimately, the simulation results obviously reveal the efficacy of the proposed IM drive.

Carbon fibers (CFs) are indispensable materials in our daily life. The excellent bearing capacity, remarkable dielectric property, ease of production, and corrosion resistance of carbon fiber reinforced polymer (CFRP) composites distinguish them from all other options in addition to them, CFRPs may also shield from electromagnetic interference (EMI). In this study, two-layer CFRP with two different hematite (Fe2O3-50 nm and 325 mesh particule size) and goethite (FeO(OH)) were produced using the hand lay-up method. Then, far field electromagnetic shielding effectiveness (SE) with 700 MHz - 6000 MHz range were examined. The maximum shielding effectiveness was determined to be at 5200 MHz with 39.28 dB for 5 wt.% FeO(OH).

This introductory study suggests a formal basis for the interpretation of a continuous path in a connected matrix Lie group to be represented by the set of von Neumann ordinals which is a set-theoretical interpretation of natural numbers. In this study, it is aimed to relate the discrete recurrent structure of von Neumann ordinals to the exponential function. Since the Exponential function is fundamentally integrated into science and engineering literature this work aims to discover ties between the Exponential function and sets where, the Exponential function utilized in machine learning, loss functions; cryptography, key exchange and encryption algorithms; robotics, kinematics, trajectory planning; numerical analysis, discrete integration. Thus, the set theoretical interpretation of the exponential function has an interdisciplinary critical role. Throughout the article, necessary conjectures are postulated to interpret the rotations that form a smooth curve in terms of sets, namely von Neumann ordinals. Introduced formalizations covering Set existence axiom, unit element for set groups, interpretation of a smooth curve in terms of multiplication of exponentials, introduced a derivative operator to observe limited differentiable properties of the exponential function.

While evaluating the seismic performance of existing buildings according to TBC2018, a difficulty and complexity arouses in estimating the rotations that occur at both ends of the load carrying elements under seismic forces. Therefore, in this study, it is aimed to develop a reliable method for estimating the seismic performance of reinforced concrete (RC) buildings using simplified displacement-based formulations. Within the scope of this study, 4 RC buildings having same symmetrical floor plan but with varying number of stories, different material strengths were designed, and 3 existing RC buildings were taken into consideration. All the 7 buildings were modeled using common structural analysis software like SAP2000v20, Sta4CADv14.1, ÝdeCADv10 and ProtaStructure2022 and linear seismic performance analysis were performed. The data obtained as a result of the analysis were processed into the displacement-based formulations created within the framework of this study to determine the damage state of the columns and associated seismic performance of the existing RC buildings considering the general principles and rules given in TBC2018. It was determined that the compatibility between the column damage conditions determined according to the proposed method and the column damage status determined as a result of the hand calculation made according to the calculation principles specified in TBC2018 was 100% in both principal directions. In addition, it is found that the results found from the proposed method were conservative and generally compatible with the results obtained from the common structural analysis software.

Recently, researchers have focused on investigating various properties of asphalt mixtures using finite element method. Thanks to this method, it is possible to simulate performance tests in the laboratory and get very similar results. In this study, semi-circular asphalt mixture samples were obtained in the laboratory, and then subjected to the Semi-Circular Bending (SCB) test to determine the fracture parameters. With the help of the finite element software, 2D asphalt mixture samples were created with five different notch depths of 1 cm, 1.5 cm, 2 cm, 2.5 cm, and 3 cm. The effect of notch depth on the fracture properties of asphalt mixtures was evaluated by simulating the SCB test at five different displacement rates 0.1, 0.5, 1, 5, and 10 mm/min. The results showed that the maximum load and fracture energy values decreased as the notch depth increased. Furthermore, the cracking strength of asphalt mixtures was calculated by using the elastic-plastic fracture mechanics approach (J-integral). Finally, Response Surface Methodology (RSM) analysis was performed to determine the degree of impact of the different variables on the results. Consequently, the notch depth was more significant than the displacement rate.

In this work, various bonding techniques for the aluminum electrode were used to explore the electrocoagulation method for treating laundry wastewater. By combining the laundry water in specific ratios (1: 1: 1,5 ratio of the wastewater after prewash, main wash, and rinsing), the wastewater was characterized. Aluminum electrodes were employed as the anode and cathode, and purification was conducted using monopolar parallel (MP-P), monopolar series (MP-S), and bipolar parallel (BP-P) in various connection configurations. For each bonding form, the impacts of process variables like pH, current density, and time on COD, MBAS, and turbidity removal were examined. In the experiments, the maximum removal efficiencies for COD, MBAS, and turbidity, respectively, were obtained in the form of MP-P binding, at pH 5.5 for 15 minutes and at a current density of 5 mA/cm2. The corresponding values were 80%, 97%, and 97%, respectively. The optimum removal conditions in the system examined with a monopolar parallel connection were pH 5.5, duration 15 minutes, current density 5 mA/cm2, temperature 25 ○C and stirring speed 200 rpm. The optimal removal efficiencies for MBAS, COD, and turbidity were determined to be 97%, 80%, and 96%, respectively.

In this study, 20 different types of magmatic-origin natural stones commonly used in the construction sector were subjected to the most prevalent aging effects in nature, namely freeze-thaw and thermal shock. Prior to and after the aging tests, the Solar Reflectance Index (SRI) values of each sample were calculated by measuring their solar light reflectance values and solar light scattering values. Additionally, the surface color measurements of each sample were taken according to the CIA color index, and the color change (∆E) values were calculated.
The primary objective of this study is to determine the changes in SRI and ΔE values of natural stones due to freeze-thaw and thermal shock aging and to examine the impact of the findings on the formation of urban heat islands.
As a result of the study, it was determined that the SRI values of the samples were higher after both aging experiments compared to before the aging experiments. When examining ΔE values, it was found that thermal shock experiments caused more significant color changes compared to freeze-thaw experiments. It has been determined that the overall increase in both SRI and ΔE values will contribute to the reduction of the urban heat island effect.

The idea of designing products from fabric waste is not new in clothing applications. The main idea of the applications lies in the development of production methods that do not harm humans and the environment. The demand for clothing products is increasing, which does not pollute the environment and respects natural resources. Which increases environmental sensitivity with consumer awareness. This demand has increased efforts to evaluate textile waste with sustainable methods. Clothing collections with high added value prepared with waste materials are becoming more important in the designer-producer and consumer triangle day by day. Nowadays, natural dye applications with waste fabrics are evaluated as a different approach for clothing designers. And the rich images on waste fabrics that are obtained with these applications.
In the study were conducted textile surface experiments with sage, tea, linden, pear peel, ginger, turmeric and cinnamon peel on waste fabric Sile cloth using different mordant materials. The method of the research was carried out in two stages. At the first stage, coloring recipes with the application of natural dyes were created. In the second stage, the design processes are included in the capsule collection. And the collection has been completed with 3D modeling and prototyping, which are one of the indispensable applications of the sector. The collection is aimed with the development of a production model with a strong environmental aspect. The findings from the research have shown that the garment design process has developed differently from the standard production models of natural dye applications with waste fabrics. The biggest difference is the "uniqueness" feature brought to the clothing collections.