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In many reinforced concrete structures, the effects of earthquakes are jointly resisted by reinforced concrete (R/C) frames and reinforced concrete (R/C) coupled shear walls. The coupling beams connecting the R/C shear walls differ in used material and reinforcement steel bar layout. The aim of this study is to examine the effects of different R/C coupling beam models on structural performance. In this study, nonlinear pushover analyses were performed on 14-storey structure model in which columns and coupled shear walls are used together as vertical carriers according to the ground acceleration of the Istanbul Atatürk Airport region. When the results of the analyses were examined, it was observed that the composite and diagonally reinforced coupling beam models provided high horizontal load resistance but had a lower displacement capacity than the double beam – coupling beam model., Betonarme yapıların birçoğunda deprem etkileri, kolon ve kirişlerin oluşturduğu çerçeveler ile bağ kirişli perdeler tarafından birlikte karşılanmaktadır. Betonarme perdeleri birbirine bağlayan bağ kirişleri ise kullanılan malzeme ve donatı düzeniyle farklılık göstermektedir. Bu çalışmanın amacı, farklı betonarme bağ kirişi modellerinin, yapı performansına olan etkilerinin incelenmesidir. Çalışmada 14 katlı, düşey taşıyıcı olarak kolon ve bağ kirişli perdelerin beraber kullanıldığı yapı modelinin, İstanbul Atatürk Havaalanı bölgesinin yer ivmesine göre doğrusal olmayan itme analizleri yapılmıştır. Yapılan analiz sonuçları incelendiğinde kompozit ve diyagonal bağ kirişli modelinin yüksek yatay yük dayanımı sağladığı, ancak çift bağ kirişi modeline göre deplasman yapabilme kapasitesinin daha düşük olduğu görülmüştür.

Oksidatif stresin başta kanser olmak üzereateroskleroz, hipertansiyon ve kardiyovasküler hastalıklar gibi pek çokhastalığın patogenezinde rol oynadığı çeşitli araştırmalar sonucundagörülmüştür. Fenolik bileşikler ise insan sağlığı bakımından antioksidanfonksiyonları ile ön plana çıkan maddelerdir. Fenolik antioksidanların serbestradikaller ile reaksiyona girme eğilimi antioksidan aktiviteyi tanımlamaktadır.Bu çalışmada 10 adet fenolik bileşik gaz etanol ve su fazlarında Spartan 14 programı ile DFT//B3LYP metodu ve 6–31+G(d) temel seti ile HAT, SET-PT ve SPLET oksidasyon mekanizmaları gaz, su ve etanolfazlarında modellenmiştir. Elde edilen verilere göre BDE, ETE, PA, IP, PDE veΔ(EHOMO-ELUMO) değerleri hesaplanarak antioksidan aktiviteleri sıralanmıştır. Yapılan hesaplamalardan elde edilen tüm sonuçlar değerlendirildiğinde bileşik 1olarak tanımlanan 2-hexadecyl-2,5,7,8-tetramethylchroman-6-ol molekülününantioksidan aktivitesi çalışılan yöntem ve fazlarda en yüksek olarakbulunmuştur., Oxidativestress is implicated in various disease pathologies including cancer,atherosclerosis, hypertension, and cardiovascular disease. Phenolic compoundshave antioxidant functions in terms of human health. The tendency of phenolicantioxidants to react with free radicals identifies their antioxidant activity.In this study, HAT, SET-PT and SPLET oxidation mechanisms were modeled in thegas, water and ethanol phases with the DFT // B3LYP method and 6-31+G(d) basisset with 10 phenolic compounds using Spartan 14. Antioxidant activities wereranked by calculated BDE, ETE, PA, IP, PDE and Δ(EHOMO-ELUMO)values ​​according to the obtained data. The antioxidant activity of2-hexadecyl-2,5,7,8-tetramethylchroman-6-ol, identified as compound 1, wasfound to be highest in the methods and phases studied when all the resultsobtained from the calculations made were evaluated.

Refractory high entropy alloys (RHEAs) with multiple principal elements constitute a new paradigm in alloy design and have gained recent interest for advanced technical applications due to their unique properties and mechanical stability at high temperatures. However, the refractory metals that make up these alloys are pretty expensive, and they cause RHEAs to exhibit low plasticity behaviour at room temperature. The high stability properties of RHEAs from room temperature to high temperatures limit their machinability with traditional cutting methods. Therefore, it is vitally important to economically machine these alloys while preserving their mechanical properties and minimising waste. For this purpose, in this study, the machinability of a HfTaTiVZr RHEA was evaluated with wire electric discharge machining (WEDM). The surface morphology, crack formation, and mechanical characteristics of the surface layer were investigated as a function of three different cutting conditions: rough cutting, semi-finishing, and finishing. The RHEA was precision cut in three passes by reducing the volume of material in each pass, resulting in better surface quality with the optimal cutting speed and metal removal rate. However, rough cutting gave better results than semi-finish and finished cutting processes in preserving mechanical properties.

Antimony triselenide (Sb2Se3) is one of the most promising absorber material choices among the inorganic semiconductors that has attracted much attention today. However, highest recorded efficiencies for Sb2Se3 solar cells are still lower than ideal. Exploring antimony selenosulfide (Sb-2(SxSe1-x)(3)) to increase device performance is one option because some features of alloyed Sb-2(SxSe1-x)(3) depend on composition such as bandgap and band position. In this study, two-step process was used to grow Sb-2(SxSe1-x)(3) thin films. In the first stage, Sb2Se3 thin films were deposited on soda lime glass substrates using direct current magnetron sputtering technique. In the second stage, Sb2Se3 thin films were exposed to sulfurization process in a quartz ampoule to obtain Sb-2(SxSe1-x)(3) thin films. Characterization results showed that morphological, optical, and structural properties of Sb-2(SxSe1-x)(3) thin films grown by presented method were highly dependent on amount of sulfur in the films. By the adjustment of the S/S + Se atomic ratio, Sb-2(SxSe1-x)(3) absorber materials with suitable bandgap, favorable orientation and compact morphology can be obtained for photovoltaic applications.

Kişi başına düşen enerji tüketiminin artmasıyla beraber, arz-talep dengesinin sağlıklı bir şekilde devam ettirebilmesi için enerji santrallerine olan yatırımlar devam etmektedir. Oluşan temiz enerji bilinci, çevreci ve uzun ömürlü Güneş Enerji Santrallerine (GES) olan yatırımları gün geçtikçe artırmaktadır. Yaşanan Kovid-19 pandemisi süresince, enerji tüketimlerinin çoğu yenilenebilir santrallerinden karşılanmış ve GES’den üretilen elektrik, büyük paya sahip olmuştur. Yapılan bu çalışmada, özellikle Türkçe kaynaklar içerisinde GES’in hammadde kaynağı olan güneş ışınımları ve ülkemizin güneş potansiyeline dair yapılan araştırmalar incelenmiştir. Güneş potansiyelinin, üretim potansiyeline dönüştürülmesinde oluşan kayıplar ve üretim potansiyelin artırılmasına yönelik konular araştırılmıştır. Ayrıca İskenderun Teknik Üniversitesi Kampüsü içinde bulunan bina çatısına 60 kWp GES tasarlanarak, PVGIS, PVsyst, SMA Web Desing yazılımları ile tahmini elektrik üretimleri hesaplanmıştır., With the increase in energy consumption per capita, investments in power plants continue in order to maintain the supply-demand balance in a healthy way. With the awareness of clean energy, investments in Solar Power Plants (SPP) are increasing day by day due to its environmentally friendly, longevity. During the Covid-19 pandemic, renewable power plants supplied most of the energy consumption, and electricity generated from SPP had a large share. In this study, especially in Turkish sources, the researches on solar radiations, which are the raw material source of SPP, and the solar potential of our country were examined. The losses in transforming solar potential into production potential and increasing production potential has been investigated. Besides, 60 kWp SPP was designed on the building roof within Iskenderun Technical University Campus and average electricity generations calculated by PVGIS, PVsyst, SMA Web Desing software were calculated.

In this work, single crystals of superconducting Fe1-xPbxTe0.5Se0.5 (x = 0.0, 0.01, 0.05, and 0.1) were grown by self-flux method. The structural, electrical, and mechanical properties of prepared samples were investigated. Structurally, it was determined that as the Pb ratio increased, the a- parameter of the crystal structure increased and the c-parameter decreased. SEM analysis showed that there was no significant microstructural change in Pb substituted FeSeTe material compared with the unsubstituted sample. There was a growth in the form of single-crystal sheets with thicknesses between 700 nm and 2 mu m. It was observed that the Pb substitution was not shown any positive change in the electrical properties compared to the unsubstituted FeSeTe system, and superconductivity deteriorated as the Pb concentration was increased. Similar trends were obtained both for the upper critical field, H-c2(T), and a characteristic length, xi(c). Relation between the mechanical properties and substitution ratio was also investigated. The hardness profiles value was found in the range of 0.90-0.49 GPa, while the elastic modulus was obtained between 19.4 and 7.84 GPa depending on the Pb substitution. It was seen that these values were slightly lower than the results obtained for unsubstituted FeSeTe material. This shows that Pb substitution has an effect on the elasticity of FeSeTe material.

Most robotic systems consist of heavy machine elements that help reduce the vibrations generated by motion and that support good positional accuracy. Large-sized actuators are needed for such systems. Energy consumption significantly increases in oversized robotic systems. The proposed solution to which is to design robotic systems in lightweight and flexible forms. This makes possible smaller overall structure and actuator sizes. However, such systems suffer from residual vibrations. One well-known control solution to residual vibration problem could be input shaping techniques. In this study, a new Fuzzy Logic-based intelligent input shaping selection technique has been proposed. With this proposed approach, it is possible to set optimum settling time, positioning accuracy of robotic systems, and minimum residual vibrations by implementing the crucial open-loop control approach. Comprehensive experience is needed to overcome design issues on command shaping and system modeling. Based on these design criteria constraints and extensive knowledge requirements, the recommended solution is a Fuzzy Logic-based intelligent input shaping technique for accurate modeling and parameter estimation of the systems. The proposed approach is a Fuzzy Logic-based intelligent input shaper selection and input shaper setting determination algorithm. The applicability of the proposed method was verified on the Quanser Flexible Link experimental setup.

Two new random donor-acceptor (D-A) copolymers, signed as P1 and P2, were designed and synthesized. Electrochemical and spectroelectrochemical measurements were performed to investigate absorption, energy levels, electronic and optical band gaps for comparison. The polymers were used as donor polymers in the active layer to fabricate non-fullerene, bulk heterojunction (BHJ) organic photovoltaics (OPVs). Investigations were carried out through the conventional BHJ structure; ITO/PEDOT: PSS/Active Layer/LiF/Al, where active layer consists of 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene (ITIC) as the acceptor and thienopyrroledione containing donors. The device based on P1:ITIC(1:1) blend with a thickness of 161 nm gave the best performance with a power conversion efficiency (PCE) of 7.94%, an open-circuit voltage (V-OC) of 0.86 V, a short-current density (J(SC)) of 18.45 mA cm(-2) and a fill factor (FF) of 50.12%. The highest PCE obtained from P2 based organic solar cell is 1.96%. P2 exhibited low solubility attributed to the lack of alkyl groups enhancing polymer solubility, electronic properties, and photovoltaic performances. The research outputs exhibit that introduction of alkyl chains on the polymer backbone can enhance device performance. (C) 2021 Elsevier Ltd. All rights reserved.

In this experimental study, a composite structure was obtained by combining apple pulp wastes with slag wastes. Electromagnetic field characteristics of test samples have been determined. In the scope of the study, dry apple pulp and slag wastes were transformed into square plate form using a specially designed mold and a pressing bench with a capacity of 50 tons. The measurements were carried out in the 3-18 GHz frequency band in the microwave laboratory. In the measurements, five different measurement results were obtained: air, high quality commercial absorber, pure apple pulp, 50 g apple pulp with slag and 150 g of slag added apple pulp. The results of the measured samples were compared and interpreted with the results of air and high-quality commercial absorber material. As a result, the samples formed by pure apple pulp, 50 g slag-added sample and 150 g slag-added sample in terms of electromagnetic permeability similar results were obtained. The slag-added sample of 50 g performed better absorption in certain frequency regions than the slag-added sample of 150 g. In addition, it produces close transmission values in three samples in the 8-12 GHz X-band frequency range. In addition, considering the absorption values of the slag-added structures, it was determined that they absorb to signals 90% on average in the frequency regions of 8 GHz and above.

In this paper, we present a linear to circular polarization converter integrated in a concrete structure to eliminate signal transmission problem originated from the concrete buildings in microwave regime. Two polarization converter samples and a control specimen made by traditional concrete are designed and their signal transmission responses are compared experimentally. Axial ratio values which can be calculated by the ratio between the co-polar transmission and cross-polar transmission results of the proposed samples are below 3 dB and highly sufficient for linear to circular polarization conversion activity. The operating frequency for the proposed sample 1 is between 6 and 6.5 GHz with 500 MHz of bandwidth. The proposed sample 2 exhibits dual-band operation covering frequency bands, 4.58–5.13 and 6.0–6.4 GHz with bandwidths of 550 and 400 MHz, respectively. Operating frequencies of the samples are in the WIMAX frequency bands. In addition, the liner to circular polarization converter design integrated to concrete has a huge potential to improve reflection and directivity parameters of many antennas if it is considered as a radome.

In this study, the holes of glass fiber reinforced polymer (GFRP) and multi-walled carbon nanotubes (MWCNTs) doped GFRP composite materials were drilled using abrasive water jet (AWJ), CO2 laser cutting, orbital drilling, and punching methods; the effects of these methods on hole quality were determined. The hole entry and exit dimensions were obtained equal and in the desired size by orbital drilling; thus, kerf formation was prevented due to the lateral and face milling of the end mill. The surface hardness change was not observed in the hole circles obtained with the orbital drilling and punching methods. However, epoxy hardening was observed in the hole circles obtained by laser cutting due to the heat effect of laser beam. In AWJ method, matrix-fiber integrity was disrupted, and delamination was observed due to the effect of water pressure and kinetic energy; consequently an increase in material thickness was observed and surface hardness decreased. It was determined that MWCNTs additive increased the surface hardness of composites and maintained its hardness and durability in post-cutting measurements. Splintering and burring were not seen in any method, but fiber carbonization was observed in the inner parts of the hole due to thermal effects in laser cutting.

The purpose of this study is to improve the gain and directivity of the microstrip patch antenna by means of metamaterial (MTM) structures. As it is known, antennas have power densities in a certain direction, and the radiation curves of the antennas are shaped by orienting them according to this power density. Based on this feature of the antennas, it is aimed to improve the gain and directivity of microstrip patch antennas with the most suitable structures thanks to metamaterial (MTM) structures. The MTM structures designed are interacted with the antenna. Then, the frequency, gain and directivity of the antenna are trained by the artificial neural network technique to estimate the most appropriate values. As a result, the gain and directivity of the antenna are improved by the interaction of microstrip patch antenna and MTM structures and the results are interpreted on the figures.

Nanofibers can be interleaved into polymers and improvements in mechanical properties such as resistance to impact, delamination and debonding as well as enhanced ductility can be obtained. In this work, GFRP laminated composites were interleaved to non-woven nylon 6,6 nanofiber mats which were generated by the electrospinning method. Four kinds of configurations were considered; two pure configurations where GFRP had two and four glass fiber layers and the other two kinds of nanofiber modified configurations that had one and three nylon 6,6 nanofiber mats being interleaved in GFRP. Those specimens were then investigated for their impact resistance, energy absorption and tensile strength capabilities in regard to low-velocity impact and tensile tests. The results showed that adding nylon 6,6 nanofiber mats can increase energy absorption values of the modified specimens, but some decrease in load capacities could be observed.

Most of the studies on conventional fuel types that can be used in internal combustion engines have been made in order to improve performance values. Nowadays environmental problems have shown that emission values are more important and interest in low carbon alternative fuels has highly increased in recent years. In this study, performance and emission values of soybean biodiesel (B25) fuel mixture used in diesel engine were investigated in detail by making different ratios of hydroxy (HHO) enrichment (3, 5 and 7 L/min). HHO enrichments increased brake torque and power outputs with direct correlation to flow rate amount; at the same time brake specific fuel consumption has decreased. Also, one of the main objectives of this study is to predict the optimum hydrogen requirement against performance reductions and NOx formations among test fuels (3, 5, and 7 L/min HHO enriched B25), too by using artificial intelligence. For developing the ANN structure, Levenberg-Marquardt (LM) learning algorithm was used to adjust the weights in the cascade forward network. The results show that the ANN model has 95,82%, 96,07%, and 92,35% estimation accuracies for motor torque, motor power, and NOx emission, respectively. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Hydrogen is the most abundant element in the world and produces only water vapor as a result of chemical reaction that occurred in fuel cells. Therefore, fuel cell electric vehicles, which use hydrogen as fuel, continue its growing trend in the sector. In this study, an energy distribution comparison is carried out between fuel cell electric vehicle and fuel cell hybrid electric vehicle. Hybridization of fuel cell electric vehicle is designed by equipped a traction battery (15 kW). Modeled vehicles were prepared under AVL Cruise program with similar chassis and same fuel cell stacks for regular determining process. Numerical analyses were presented and graphed with instantaneous results in terms of sankey diagrams with a comparison task. WLTP driving cycle is selected for both vehicles and energy input/output values given with detailed analyses. The average consumption results of electric and hydrogen usage is found out as 4.07 kWh and 1.125 kg/100 km respectively for fuel cell electric vehicle. On the other hand, fuel cell hybrid electric vehicle's average consumption results figured out as 3.701 kWh for electric and 0.701 kg/100 km for hydrogen consumption. As a result of this study, fuel cell hybrid electric vehicle was obtained better results rather than fuel cell electric vehicle according to energy and hydrogen consumption with 8% and 32%, respectively. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

© 2021 Hydrogen Energy Publications LLCIn the presented paper, energy and exergy analysis is performed for thermochemical hydrogen (H2) production facility based on solar power. Thermal power used in thermochemical cycles and electricity production is obtained from concentrated solar power systems. In order to investigate the effect of thermochemical cycles on hydrogen production, three different cycles which are low temperature Mg–Cl, H2SO4 and UT-3 cycles are compared. Reheat-regenerative Rankine and recompression S–CO2 Brayton power cycles are considered to supply electricity needed in the Mg–Cl and H2SO4 thermochemical cycles. Furthermore, the effects of instant solar radiation and concentration ratio on the system performance are investigated. The integration of S–CO2 Brayton power cycle instead of reheat-regenerative Rankine enhances the system performance. The maximum exergy efficiency which is obtained in the system with Mg–Cl thermochemical and recompression S–CO2 Brayton power cycles is 27%. Although the energy and exergy efficiencies decrease with the increase of the solar radiation, they increase with the increase of the concentration ratio. The highest exergy destruction occurred in the solar energy unit.

This paper develops a hydrogen generator prototype that is for fuel cell systems used in portable applications. This generator is designed based on the use of solid-state hydrides with high hydrogen storage capacity in the catalytic hydrolysis reaction. Some using problems such as unstable hydrogen production, one-off service life, heavy or large-volume storage system, and short duty time can be avoided in moveable applications when the use of the produced prototype. In addition, A simulation model and an autonomous control algorithm, which evaluates the hydrogen generation and temperature responses of the prototype, are developed. The results confirm that the performance of a portable and autonomous prototype with 4 parts and 1-hour hydrogen production capacity is enough for small fuel cell applications. As a result; the tightness and performance tests of the prototype were investigated using different catalyst samples for 1 hour, and the results were investigated in depth. The average flow rate of this 4-part autonomous generator is approximately 3.00 L/min.gcatalyst during 1 h. In the working cycle, the soft ripples have spied on the hydrogen-produced amount from time to time.

Solar energy has a key role in producing clean and emissions-free power compare to conventional methods. However, sustainable development also requires a reliable and predictable energy source. It also needs methods to measure and predict predictable supply. The main aim of the study is to improve reliable and precise solar radiation prediction models on monthly mean daily basis using various machine learning techniques. Simple Membership Function and Fuzzy Rule Generating Technique (SMGRT), which does not require error and trial for model adjustment, is the first-choice model in this study. Experience and observations about the model will greatly reduce the volume of processing for the fuzzy SMGRT model. On the other hand, Deep Learning (DL) and Adaptive Neuro-Fuzzy Inference System (ANFIS) have become increasingly popular in understanding nonlinear data structures and solving complex problems. Therefore, DL and ANFIS were also applied to estimate solar radiation. The data set used in the study were created using sunshine duration (s), extra-terrestrial solar radiation (H0), relative humidity (RH), cloudiness (C), air temperature (T) and soil temperature (ST) parameters. Estimation performance of models was evaluated by using several statistical indicators which are Mean Bias Error (MBE), Mean Square Error (MSE), Root Mean Square Error (RMSE), and Correlation Coefficient (R2). When the performances of the models were compared, it was seen that all three models obtained remarkable results. In addition, it was shown that the models performed well based on the metrics in the testing phase. The SMGRT model has slightly better performance than DL and ANFIS for different input combinations. SMGRT Model 1 (with inputs H0, s, and T) shows the best statistical performance (MBE = 0.156, MSE = 1.878, RMSE = 1.371, and R2 = 0.960) not only in SMGRT models but also in others.

In this study, hydrolysis reaction performances of raw BFS powder and metal powders (which are ingredients of BFS) that are using as a catalyst are compared. Hydrogen generation by hydrolysis reaction of the Al and Fe2O3 Nano & Granule powders with sodium borohydride (NaBH4) addition in water was studied by using different catalysts amount at reaction vessels. The measured values of reaction temperatures and hydrogen flow rates were measured by using high-precision equipment. As a result of the obtained data, it was determined that Fe2O3 and Al catalysts have advantages over hydrogen production rate and fuel conversion, also, these experiments show a very high success in different parameters, and create promising effects in the reactions. Among the Al catalyst samples, the highest efficiency performances are achieved with Al Nano catalyst samples at 85.31 °C preheat with an instantaneous hydrogen generation rate of approximately 11.226 L / min for 33 minutes. Among the Fe2O3 catalyst samples, the highest efficiency performances are achieved with Fe2O3 Nano catalyst samples at 50 °C preheat with an instantaneous hydrogen generation rate of approximately 29.91 L / min for 12 minutes.

Laser-clad AlCrFeCoNi high entropy alloy (HEA) coatings, produced on the surface of AISI 316 L stainless steel, were pack-borided at 1000 °C for 4 h in open air, high-purity Ar and vacuum environments. The HEA, which had an initial hardness of 6.14 ± 2.06 GPa, formed a complex boride layer consisting of (CoFe)B2, (CrFe)B2 and Cr2Ni3B6 phases on its surface, with hardness ranging from 15.95 ± 0.7 to 20.15 ± 4.50 GPa as a result of the boriding process. While the greatest boride layer thickness was obtained in the sample borided in vacuum, the highest surface hardness was obtained in the sample borided in air. The borided coatings showed improved wear resistance and lower friction values compared to the untreated control samples, both at 25 °C and 650 °C. The borided coatings also showed reduced coefficients of friction at 650 °C. The wear losses at 650 °C significantly exceeded those at 25 °C.

In this numerical and experimental study, we designed sinusoidal located concrete-based boreholes which are candidate for seismic shielding applications. To attenuate seismic wave transmission in an area, proposed design is created in most dangerous part of seismic frequencies which corresponds 1-15 Hz band. Firstly, transmission loss characteristics of proposed design is obtained numerically, and it is clearly shown that proposed design has multiband blocking capability. Afterwards, total surface displacements were plotted, analysed and explained. Thus, proposed design attenuates seismic wave transmission according to numerical results. Moreover, to support proposed design, various experimental measurements were carried out by using a harmonic vibration source and 14 accelerometers as sensors. Experiments conducted in time domain and obtained results were converted to the frequency domain by fast Fourier transform, and mapping processes were done by interpolation technique. The obtained measured map of the seismic radiation between 5 and 15 Hz bands is given, and a good matching between simulations and experiments has been seen. As obtained numerical and experimental results, the proposed metamaterial structure could be used in seismic shielding applications because of its highly blocking capability of seismic wave transmission.

In this study, synthesis of two multifunctional acetic acid functionalized carbazole bearing monomers; 243,6-bis(2,3-dihydrothieno [3,4-b] [1,4]dioxin-5-yl)-9H-carbazol-9-yl)acetic acid (Ml) and 3,6-dithien-2-yl-9H car bazol-9-ylaceticacid (M2) via Stille cross-coupling reaction was reported. Obtained monomers were electro-chemically polymerized in 0.1 M TBAPF(6)/DCM/ACN (5:95, v:v) solution and characterized in terms of electrochemical, spectroelectrochemical and electrochromic switching behaviors. When poly-2-(3,6-bis(2,3-dihydrothieno[3,4-b] [1,4]dioxin-5-yl)-9H-carbazol-9-ypacetic acid (P1) and poly-3,6-dithien-2-yl-9H car bazol-9-ylaceticacid (P2) were compared in terms of electrochemical behaviors, by virtue of the electron-rich EDOT units in the P1 chains, the polymer film exhibited lower monomer oxidation potential at around 1.05 V. Both polymers exhibited neutral state yellow color with similar optical band gaps and multi-electrochromic behaviors under different applied potentials. Insertion of thiophene unit instead of ethylene dioxythiophene (EDOT) unit on the polymer backbone enhanced the electrochromic and optical contrast properties and P2 showed the higher optical contrast then P1. Furthermore, owing to the promising electrochromic properties of P2 like red shifted absorption and higher optical contrast, a prototype P2 and PEDOT bearing solid state electrochromic devices (ECDs) were constructed and characterized. P2 and PEDOT comprising ECD works between yellow and blue colors at - 2.0 V and at 2.0 V respectively, with 41% optical contrast and 1.3 s switching time at 580 nm. Furthermore, P2 was used for energy storage applications before and in the present study it was used for ECD applications with promising results which make acetic acid functionalized carbazole derivatives mull-purpose new generation materials.

In this study, Ni-based Inconel 718 coatings were additively manufactured on the surface of AISI H13 work tool steel by electro-spark deposition (ESD). Some of the electro-spark deposited samples were boronized at 1000 ? for 5 h to evaluate the effects of boronizing on microstructure, high-temperature wear, and corrosion resistance. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), 2D pro-filometry, wear and electrochemical corrosion testing was used to characterize the surfaces, microstructures, microhardness, some mechanical properties, high-temperature wear, and corrosion resistance of the applied coatings. Wear tests were performed at room temperature and 650 ?, and corrosion tests were performed in 3.5% NaCl at room temperature, considering the applications of AISI H13 and Inconel 718 alloys. The characterization studies showed evidence of microcracking and oxidation in the as-deposited Inconel 178 coatings. In the boronized Inconel 718 coatings, the oxides and microcracks were slightly reduced. The hardness of the boronized Inconel 718 coating was increased to about four times the hardness of the as-deposited Inconel 718 coating, and this significantly improved its wear resistance. The highest wear resistance was achieved with the boronized coating, while the best corrosion resistance was obtained with the as-deposited coating. The improvements in wear resistance provided by boronizing have the potential for expanding the applications of Inconel 718 coatings in machine components.

WOS: 000524097200032, This paper addresses an improved optimization method to enhance the energy extraction capability of fuel cell implementations. In this study, the proposed method called Dynamic Cuckoo Search Algorithm (DCSA) is tested in a stand-alone fuel cell in order to control the system power under dynamic temperature response. In the operational process, a fuel cell is connected to a load through a dc-dc boost converter, and DCSA is utilized to adjust the switching duration in dc-dc converter by using voltage, current and temperature parameters. In this way, it controls the output voltage to maximize power delivery capability at the demand-side and eliminates the drawback of conventional cuckoo search algorithm (CSA) which cannot change duty cycle under operating temperature variations. In this regard, DCSA shows a significant improvement in terms of system response and achieves a more efficient power extraction than the conventional CSA method. In order to demonstrate the system performance, the stand-alone fuel cell system is constructed in Simulink environment via a processor-in the-loop (PIL) based digital implementation and analyzed by using different optimization methods. In the analysis section, the results of the proposed method are compared with conventional methods (perturb&observe mppt, incremental conductance mppt, and particle swarm optimization). In this context, convergence speed and efficiency analysis for both methods verify that the DCSA gives original results compared to conventional methods. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

WOS: 000519806700073, In this study, composites composed of glass fiber reinforced-epoxy laminates interleaved with electrospun polyvinylchloride (PVC) nano-fibres were designed for radar absorption investigations. The laminated composites which were produced in special molds were obtained by placing woven glass fibers between each of PVC nanofiber mats, and the composites were produced in three different forms as pure, multi-walled carbon nanotubes doped and graphene doped. The morphologies of the PVC nanofiber mats were analyzed by scanning electron microscope. The radar absorption efficiencies of the composites in the individual and different combinations were measured in the 3-8 GHz frequency band. Experimental results show that the produced graphene-added composite material has improvable microwave absorption effect at several points in 3-8 GHz band to provide excellent absorption in future studies. The graphene doped structure was found to have a certain absorption characteristic up to 33.82% at a constant frequency. Besides, various strong absorption frequency points have been obtained in the related frequency range. The cascaded graphene doped composite layers can provide broadband absorption for stealth technology.

Sunulan çalışmada; kullanıcı tarafından kontrol edilen bir robot el sistemi için çalışma yapılmıştır. Sistemin nesne kavrama kuvveti hassasiyetinin sağlanması amacıyla kavrama kuvvetinin kontrol sorunu üzerine durulmuştur. Bunun yanı sıra nesneye uygulanan kuvvetin kullanıcıya geri bildirimi için haptik geri bildirim sistemi oluşturulmuştur. Robot elin kullanıcı komutu doğrultusunda nesnelere uyguladığı kuvvetin kontrolünde, bulanık mantık önerilmiş ve uygulanmıştır. Kullanıcı bulanık mantık kontrolcüye tut, bırak, sık gibi farklı kavrama komutlarını gönderebilmektedir. Bulanık mantık kontrolcü ise kullanıcı komutu doğrultusunda objeye uygulanan kuvveti kontrol etmektedir. Ayrıca kuvvet sensöründen gelen veriler bulanık mantık kontrolcü ile değerlendirilerek haptik geri bildirim sisteminde bulunan titreşim motorlarının titreşim şiddeti ayarlanmaktadır. Böylelikle kullanıcı, hem objeleri ne kadar kuvvetle sıktığını hissedebilmekte hem de sadece bir kavrama komutu göndererek nesnenin uygun kuvvette kavranmasını sağlayabilmektedir. Oluşturulan sistem objelerin kavranması esnasında oluşan kavrama kuvvetinin kontrol sorunu ve his geri bildirim eksikliği sorunlarına bir çözüm niteliğindedir., In the presented study; work has been done for a robotic hand system controlled by the user. In order to ensure the object grip force sensitivity of the system focused on control problem of clutch force. In addition, a haptic feedback system is provided for feedback to the user of the force applied to the object. Fuzzy logic is proposed and implemented for controlling the force exerted by the robot hand on objects in accordance with the user command. The user can send different griping commands to the fuzzy logic control system such as grasp, drop and tight grasp. The fuzzy logic controller controls the force applied to the objects in according to the user command. In addition, the data from the force sensor are evaluated by fuzzy logic controller. As a result of the evaluation, the vibration intensity of the vibration motors in the haptic feedback system is adjusted. Thus, the user can feel the grasping force of the objects. Besides, the robot hand has been grasping the objects in the appropriate force range according to the user command. The created system is provides a solution to the problem of force control and lack of haptic feedback in robot hand applications.

WOS: 000500060400001, Hydrogen can be considered as the most promising fuel towards the greenization. Developed and developing countries around the world have formed their research, investments and directives on hydrogen. The leading countries in this field can be cited as members of the European Union and the United States. Laws and regulations have been shared with the public under the aegis of the established policies. Additionally, determined targets for the short, medium and long term and their feedbacks are recorded by the reports of the competent authorities. Although the Republic of Turkey was aware of the importance of the issue, though there is no open source inventory as disclosed. In Turkey, governmental organization, General Directorate of Energy Affairs (YEGM), and foundations, such as the National Hydrogen Association (NHA), have been encouraging and supporting multidisciplinary studies and activities within the country and internationally. In this study, it is aimed to provide numerical analyses from 1970 to the present by considering hydrogen energy. Related information and data were compiled from online resources on scholarly publications, organizations, groups, books and book chapters, master and doctorate theses, patents received and completed projects. It is also aimed to create a unique information source to refer with respect to planning and activities.

In this study; it is aimed to improve the rheological properties of Na-Bentonite water based drilling muds (WBDM) by graphene, graphene oxide (GO) and graphene oxide functionalized with gold nanoparticles (AuNPs/GO) at 0.0005–0.01 (% w/v) ratios. For this purpose, firstly; AuNPs, graphene, GO and AuNPs/GO were synthesized, and then characterized by SEM, TEM, EDX, RAIRS and XPS. Synthesized and characterized nanomaterials were added to WBDM at a rate of 0.0005% to 0.01% (w/v), and finally, rheological and filtration loss analyzes of water based drilling muds containing nanomaterials were carried out according to American Petroleum Institute Standards. As a result of this study, in which nanomaterials were used to improve the properties of water based drilling mud; plastic viscosity (PV), apparent viscosity (AV), yield point (YP), gel strength (10 s and 10 min), respectively; it was determined that it increased by 67%, 44%, 44%, 67% and 50%, and at the same time, the filtration loss value decreased by 14%.

Depremlerin yıkıcı etkilerini azaltmak için yapılan çalışmalar, son zamanlarda üzerinde durulan araştırma konuları arasındadır. Bu çalışmada, kare, üçgen, sinüs ve daire olmak üzere dört farklı saha dizisinde çelik metamalzemeler kullanılarak titreşim etkilerini azaltmak için bir dizi simülasyon çalışmaları gerçekleştirilmiştir. Oluşan iletim kayıpları sonlu elamanlar yöntemi (FEM) kullanılarak belirlenmiştir. Simülasyon çalışmasında, çelik yapıların çap ve malzeme özellikleri ile zemin yapısı ve boyutları sabit tutulurken parametrik tanımlamalar yapılmış, kazıkların dizilişleri geometrik olarak birbirinden farklı tutulmuştur. Çalışmanın amacı, çelik için en uygun saha uygulamasını belirlemek ve saha dizilimleri sonucunda ortaya çıkan farklılıkları incelemektir. Simülasyonlar sonucunda bütün uygulamalarda yüzey titreşimlerinin 5.8 ve 8.5 Hz frekans değerlerinde önemli ölçüde kısıtlandığı görülmüştür. Ancak uygulanan saha yapıları karşılaştırıldığında, üçgen dizilimindeki sahanın diğer saha uygulamalarına göre yüzey dalgalarını daha fazla engellediği sonucuna varılmıştır., Studies conducted to reduce the destructive effects of earthquakes are among the research topics that have been focused on recently. In this study, a series of simulation studies were carried out to reduce vibration effects by using steel metamaterials in four different field sequences: square, triangle, sine and circle. The resulting transmission losses are determined using the finite integration method (FEM). In the simulation study, parametric definitions were made while keeping the steel structures and ground constant, and the arrangement of the piles were kept geometrically different from each other. The aim of the study is to determine the most appropriate field application for steel and to examine the differences that arise as a result of the field alignments. As a result of the simulations, it has been observed that the surface vibrations are significantly restricted at 5.8 and 8.5 Hz frequency values in all applications. However, when the applied field structures were compared, it was concluded that the field in the triangular arrangement prevented surface waves more than other field applications.

The understanding of the behavior of a wind turbine is difficult due to changes in weather conditions. To obtain the response of a wind turbine influenced by changes in both wind speed and its direction, using the meteorological station data is often preferred to using the real turbine data. Furthermore, simulated data can be easily extrapolated to varied turbine hub heights. In order to estimate the most effective power output in this study, a wind turbine simulation was developed. The simulation depends on the real meteorological data. For the purpose, three modeling techniques, namely Multi-Nonlinear Regression (MNLR), Adaptive Neuro-Fuzzy Inference System (ANFIS), and support vector machines (SVM) were used. In SVM learning process, polynomial and radial basis kernel functions were used. Models were compared to wind turbine measurement values in the same region for similar data. MNLR was used to determine quantify the strength of the relationship between parameters and to eliminate the ineffective parameters. Efficient parameters preferred for training and testing phases of the SVM and ANFIS. The Subtractive Clustering and Grid Partitioning methods were used to identify the inference parameters of ANFIS. According to performance evaluations, MNLR-ANFIS modeling based on Subtractive Clustering gave better results than Grid Partitioning. The results showed that proposed collaborative model could be applied to wind power estimation problems. © 2019, © 2019 Taylor & Francis Group, LLC.

WOS: 000464636400034, Including fibers in concretes improves their mechanical properties such as flexural strength, impact load resistance and limited crack propagation. The dispersion, orientation and types of the fibers placed in the concretes affect these mechanical properties. The aim of the study is to propose a standard and a novel prediction method for determining the dispersion and orientation of the concretes in which fibers are reinforced in microwave frequency range. This study demonstrates that determination of both orientation and dispersion of the fibers regardless of the fiber types in concretes is possible by extracting electromagnetic properties of the structures in microwave regime as a nondestructive method. The measurement technique requires sample under test (SUT) and two wideband linearly polarized antennas placed in the front and backside of material under the free space condition. Although there are some studies investigated the fiber content of concrete samples through certain electromagnetic techniques, the proposed novel approach concentrates on the electromagnetic behavior of the fiber reinforced concretes in a very wideband range from 3 GHz to 17 GHz. Unlike the other studies, open space measurement with the help of a vector network analyzer which is capable of measuring up to 43 GHz along with two high gain horn antennas was carried out in the laboratory environment. Time required for exact measurement of dielectric constant and loss factor of the concrete between antennas is less than a minute. A simple and confidential model is carried out to determine both orientation and dispersion of fibers in concrete by observing the changes of dielectric constant and loss factor. The determination of electromagnetic properties of concretes with fibers has potential applications for future nondestructive sensors. In addition, observation of negative dielectric constant and some other electrical properties such as low loss factor and impedance match with free space presented in the study for particular frequency intervals gives a chance for future radome applications in harsh environmental conditions. (C) 2019 Elsevier Ltd. All rights reserved.

9th International Conference on Hydrogen Production (ICH2P), WOS: 000466455000048, Last three decades, costumers and manufacturers of automotive sector have been influenced positively by Hydrogen and fuel cells (FCs). The main goal of automakers can be pointed as minimizing the fuel consumption and exhaust emissions while improving the range limits, energy efficiency and latest technology adaptation. Therewithal, electric assisted propulsion systems added to vehicles and are called as electric vehicles (EVs). For that matter, Battery Electric Vehicles (BEVs) and hydrogen Fuel Cell Electric Vehicles (FCEVs) have become the focus of researchers and producers. In this mini foreseen review, overview of the next quarter century vision of FCEVs are expressed and discussed by the helped of previous researches and with future forecast reports. The introduction part is summarized the general approach and future expectations of FCs in detailed. Technical overview is represented for FCs and FCEVs in terms of current state of technology to foreseen expectancy. Infrastructure analysis and future aspects overview part is also discussed for sector's perspective on FCEVs. The near future perspective of the FCEVs, which is seen as the next step in EVs, is discussed in detail in the next quarter century vision. Authors concluded that, between the 2030s-2050s, hydrogen FCEVs will continue their rising demand scale under the circumstances of decreasing expensive technology; enhanced energy optimization; extended range limits and increasing hydrogen refueling stations. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

WOS: 000451757200009, Research on sustainable concrete has drawn scientist's attentions on industrial by-products and wastes. Thus, consumption of raw materials would be diminished. In this study alkali activation of electric arc furnace slag (EAFS) was studied with a comprehensive test program. Different silicate modulus, sodium concentrations, curing conditions, curing temperatures and relative humidity condition variables were selected. Their effects on mechanical and micro structural behaviors of the mortar were investigated through SEM - XRD analyses. Result of this study, EAFS was activated with sodium hydroxide and sodium silicate solutions. Test results also revealed that increase in relative humidity, curing temperature and curing time had positive effects on strength parameters due to diminishing micro cracks and altering hydration reactions. With the current study utilization of EAFS is thought to be successfully disposed.

In this study, a triangular array of cylindrical holes was shown to function as a local resonator to seismic metamaterials against the vibration generator loading in the geophysics concept. The field test showed that the seismic waves applied to one side of the proposed array interacted with the triangularly arranged holes, resulting in a strong attenuation in two narrow frequency bands. The numerical analysis was carried out using simulations based on the finite element method, which provides optimal dimensions and arrangement at a sub-wavelength scale to achieve maximum attenuation against incoming seismic wave at a very low frequency range. Different band gaps were observed due to interaction of the longitudinal resonance between the cylindrical holes and vertical components of soil response under the applied wave. Experimental analysis was carried out using optimum dimensions and hole arrangements, and a strong attenuation due to impedance matching between soil and seismic metamaterials was shown. It was also observed that, at very low frequencies, the soil response was due to the inverse proportionality between the resonator length and the seismic energy wavelength applied for longitudinal resonance. Two band gaps have been observed around 25–36 Hz as shown in band diagram. The proposed structure exactly prevents the seismic wave propagation at 25 Hz and 36 Hz in accordance with band diagram. Therefore, the proposed system can prevent the seismic waves from attaining the backside of the seismic array. The attenuation was obtained at a level of 0.00125, observed at a 0.0001 source point, measured by a speed sensor located at the back of the seismic metamaterials, with an attenuation rate of 12.5 at 8 Hz.

Purpose The purpose of this paper is to investigate the effect of doping element on the microwave absorption performance of hexagonal nano boron nitride (h-nBN)-reinforced basalt fabric (BF)/epoxy composites. A new type of hybrid composite that will be produced by the use of boron nitride as an additive that leads to increased radar absorption capability will be developed and a new material that can be used in aeronautical radar applications. Design/methodology/approach This study is focused on the microwave absorption properties of h-nBN doped basalt fabric-reinforced epoxy composites. Basalt fabric (BF)/epoxy composites (pure composites) and the BF/h-nBN (1 Wt.% h-nBN doped composites) hybrid composites were fabricated by vacuum infusion method. Phase identification of the composites were performed using X-ray diffraction (XRD), the 2θ scan range was from 10 to 60 with the scanning speed of 3°/min and surface morphologies of the composites were investigated using scanning electron microscopy (SEM). Microwave properties of samples were investigated through transmission/reflection measurements in Agilent brand 2-Port PNA-L Network Analyzer in the frequency range of 3–18 GHz. The prepared sample is positioned between two horn antennas with and without metal plate. Findings Experimental results show that h-nBN doped composite was synthesized successfully and the produced hexagonal nano boron nitride-added fiber laminated composite material has good absorption behavior when they are used with metallic sheets and good for isolation applications at many points in the 3–18 GHz band. Originality/value This paper will contribute to the literature on the use of basalt fabric, which are new types of fibers, and hexagonal nano boron nitride and the effects of boron nitride on radar absorption properties of composite material. It presents detail characterization of each composite by using XRD and scanning electron microscopy.

The thermal fatigue behavior of chromium vanadium carbide (Cr − V − C) coatings and the wear of the coatings after thermal fatigue cycling was studied. The Cr − V − C coatings were grown on the surface of a ductile iron using thermo-reactive diffusion (TRD) and subjected to thermal fatigue in the temperature range of 25 to 750 °C for up to 500 cycles. Characterizations were made using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, microhardness measurements and wear tests. The Cr − V − C coated samples displayed superior thermal fatigue and wear resistance compared to the untreated ductile iron, mainly due to the dissolution of graphite nodules in the vicinity of the surface during TRD. The dissolution of graphite reduced the possibility of failure initiating from graphite nodules and graphite-matrix interfaces. Increasing the number of cycles resulted in increased flaking and decreased wear resistance in both the Cr − V − C coatings as well as the untreated ductile iron. Although much of the Cr − V − C coating was lost (due to flaking) after thermal cycling, the absence of graphite near the surface still provided improved resistance to wear in the TRD-treated samples. The results of this study indicate that TRD coatings hold great promise for use in the industrial applications.

a bstract In this study, different types of waste aluminum produced in daily life and their pure equivalents were evaluated and compared in terms of their hydrogen generation performance through the water-splitting reaction. An experimental system was designed for the production process that consisted of electrodes, DC power supply, alkaline solution, and various waste aluminum products. The hydrogen generation rate of the aluminum source was then measured to determine the optimum conditions for hydrogen production with different types of pure and waste aluminum, normality of the aqueous solution, and applied DC voltage. The best results for micro-hydrogen generation were obtained using pure powder Aluminum, which was attributed to the increased active surface area for the reaction. For beverage can waste (and its powder form), the maximum hydrogen generation rate (cm3/g.min) was achieved using the powder form of the waste aluminum at 2 N alkaline solution. However, the total amount of hydrogen generation (cm3/g) yielded different results compared to the maximum hydrogen generation rate where, when the amount of hydrogen generation volume per mass was considered, the beverage can pieces achieved the best result under constant voltage. This result was attributed to a longer total reaction time.

The aim of this work is to investigate the effect of the hexagonal nano boron nitride (h-BN) doped epoxy on the mechanical performances and machinability behaviors of basalt fiber (BF) composites. The h-BN has used as a dopant with a weight rate of 1 wt. %. The polymer composites were prepared by the vacuum bagging method and specimens were processed with abrasive water jet machining (AWJM) to analyze the machinability of the material. A circular hole with an 8 mm size was machined by abrasive water jet (AWJ) on the composite plate with a thickness of 2.3 ± 0.1 mm using the garnet size of 80 µm as an abrasive. Taper angle and circularity of machined hole, the entry-exit hole diameter, delamination, splintering, burring, thickness, and hardness were measured. Results indicate that cutting speed has a high influence on the taper angle and circularity respectively.

In the present paper, the blast furnace slag (BFS) supported Co-B catalyst were investigated in detail. The impregnation-chemical reduction method was used while hydrochloric (HCl) acid treated BFS samples (BFS+) were prepared. Catalyst samples were analyzed in three main groups as base BFS (BFS0), BFS0-Co-B and BFS+-Co-B. The effects of these catalyst samples on hydrogen production from the solid-state sodium boron hydride (NaBH4) are analyzed in this study. The effects of some parameters such as the ingredients of blast furnace slag, the molarity of hydrochloric acid treatment, the Co percentages and the solution temperatures were investigated on the hydrolysis performance of NaBH4. The NaBH4 hydrolysis reaction with the BFS0 is treated by the BFS+-Co-B-20% catalyst was completed approximately 25 min and the hydrolysis reaction with the BFS0-Co-B-20% catalyst was completed approximately 20 min whereas the hydrolysis reaction of NaBH4 was completed in 1 h 35 min. The hydrogen production rates at pre-heated to max 40, 50 and 60 degrees C were measured as 55.12, 64.47 and 70.41 L/min.g(catalyst), respectively. According to another result of the study, the high-efficiency solid-state BFS-Co-B & NaBH4 mixtures were covered with the PVA (Polyvinyl alcohol) film to make them more resistant to environmental effects such as humidity. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

In this study, it was proposed a novel prediction model to predict compressive strength of mortar samples having different properties. For this purpose, 8 different fly ashes were used in mortar mixture as a replacement of cement by weight. Mortars including different ashes were prepared with addition of 10%, 20%, 30% and 40% fly ash. Compressive strength of the produced mortar samples were evaluated at 1, 3, 7, 28, 90 and 365 days. Totally 196 test samples were produced and mechanically tested. The relation between compressive strength values (dependent value) and SiO2 + Al2O3 + Fe2O3 content, age, and fly ash replacement ratios (independent values) were predicted by machine learning techniques such as Artificial Neural Networks (ANN) and Adaptive-Network Based Fuzzy Inference Systems (ANFIS). The findings were compared with traditional statistical method Multi-Linear Regression (MLR) to prove proposed models. According to test results it has an incentive effect for future studies to know that GA based Antis model produce better results to estimate compressive strength using chemical composition of fly as in terms of SiO2 + Al2O3 + Fe2O3, fly ashsubstation ratio in the mortar and age of the sample. (C) 2020 Elsevier Ltd. All rights reserved.

Sunulan çalışma, bir esnek robot kol sisteminin hareket kontrolüne yönelik LQR denetleyici tasarımı ile kontrol parametrelerinin optimizasyonu hakkında ayrıntılı analizler sunmaktadır. Optimizasyonun temel amacı esnek robot kol sisteminin istenilen açısal konuma en hızlı şekilde gelmesini sağlamak ve uç sapmalarını ortadan kaldırmaktır. Titreşimli Parçacık Sistemi algoritması ilk kez bu çalışma ile LQR ağırlık matrislerinin ayarlanmasında kullanılmıştır. Önerilen yaklaşımın etkinliği, Genetik Algoritma ve Yapay Arı Kolonisi gibi iyi bilenen optimizasyon algoritmaları ile karşılaştırılarak gösterilmiştir. Ayrıca çalışma kapsamında esnek robotik sistemler için kontrol yanıtının önemli parametrelerini dikkate alan bir çoklu amaç fonksiyonu da önerilmektedir. Optimizasyon algoritmalarına ait parametreler geniş bir arama uzayı taranarak belirlenmiş olup her algoritma dört farklı popülasyon değeri altında incelenerek 100 iterasyon için sonuçlar elde edilmiştir. Optimizasyon algoritmaları ile elde edilen en iyi kontrol sonuçları, esnek robot kol sistemine uygulanarak elde edilen sonuçlar teorik ve deneysel olarak karşılaştırılmıştır. Makale, tanıtılan optimizasyon algoritmalarının her biri için gerekli teorik arka plan ile uygulamaya yönelik ayrıntıları sunacak şekilde düzenlenmiştir., The presented study provides detailed analysis of the LQR controller design for motion control of a flexible link manipulator system with the optimization of control parameters. The main objective of proposed optimization ensures that the flexible link manipulator system reaches the desired angular position as soon as possible and eliminates tip deflections. The Vibrating Particle System algorithm used for the first time in the adjustment of LQR weight matrices with this study. The efficiency of the proposed approach has been showing by comparing it with well-known optimization algorithms such as Genetic Algorithm and Artificial Bee Colony. Also, multi-objective function is proposed that considers the important parameters of the control response for flexible link manipulator systems in this study. Parameters of optimization algorithms have been determined by searching a wide search space and each algorithm was examined in terms of four different population values in order to reach results for 100 iterations. Furthermore, the configurations that obtained the best control results for optimization algorithms are compared with each other according to the theoretical and experimental studies performed. The article is organized in a manner that presents the required theoretical background and the implementation-related details for each of the optimization algorithms introduced.

This paper offers a solution to the problem of detecting neonatal seizures via a transfer learning technique that judiciously reconstructs pre-trained deep convolution neural networks (p-DCNN), including alexnet, resnet18, googlenet, densenet, and resnet50. Multichannel electroencephalography (EEG) signals are converted to colour images for feeding them as an input for the p-DCNN. A deep neural network (DNN) such as a convolution neural network (CNN) may be directly used instead of transfer learning-based networks. However, a DNN requires too much training data, too much training time, and a computer with high-performance computational capability. The DNN also has several user-supplied hyper-parameters that must be tuned to obtain desirable classification success. To prevent these drawbacks, we propose a transfer learning technique to solve the neonatal seizures detection problem. Results of simulations and the statistical analysis enable us to devise a transfer learning technique employed for seizure detection.

The implementations of fuel cells (FCs) in the vehicle industry have gained great attention for the last few decades owing to simple utilization, silent operation, high efficiency and modular structure. Technological advancements show that the use of FCs in electric vehicles (EVs) will increase rapidly and cause a revolution, and will be an alternative to traditional vehicles in the future. Commercial vehicles, projects and research show that work is underway to ensure that FCEVs have sufficient performance advances for their daily transportation needs. However, the lack of a detailed study that will shed light on researchers working in this field is obvious. It aims to provide a comprehensive scientific publication on the current status and future expectations to engineers and researchers interested in this field. In the current study, numerous studies have been examined in detail and added as supplementary to the bibliography. In this context, FCEVs are classified under headings of configurations, systems components, control/management, technical challenges, marketing and future aspects. First of all, FC types and electric motors are discussed in terms of their application areas, characteristic properties and operating conditions. Power converters, which are voltage regulation and motor drive topologies used in FCEVs, are detailed according to the structural frequency of use, structure, and complexity. In the next sections, control issues for converters and technical challenges are branched for FCEVs. In final section, the current status and future aspects are reported using a large number of marketing and target data.

Drilling is one of the most common methods for the production of hydrocarbon or geothermal sources. Success of drilling operations depend on the mechanical and thermal properties of drilling mud. Since ensure direct connect between formation and surface, it is main factor which should be control in drilling. It provides some basic properties during the drilling process such as controlling the formation pressure, carrying the cuttings from bit to surface, suspending solids in the mud when circulation is stopped, forming low-permeability filter cake, maintaining the stability of the borehole, reducing friction between the drilling string and the sides of the hole, cooling and lubricating the bit, assisting in the collection and interpretation of information available from cuttings etc. One of the most significant tasks of the drilling mud is controlling the formation pressure. This pressure, also named as hydrostatic pressure, depends on the depth and mud weight. Also, the mud weight depends mainly High Gravity Solids (HGS), such as barite or calcium carbonate, in the drilling mud. Hence, it is necessary to add these materials when the weight of the mud is desired to be increased. Drilling mud is one of the most important parameters in drilling operations. The main purpose of it is to bring the cuttings from the formation to the surface. For this purpose, the drilling mud must reach a certain viscosity value in order to transport the cuttings to the surface. The viscosity, which has a significant effect on the easy transport of crumbs to the surface, should be observed regularly during drilling. These measurements are made to determine if the drilling mud is efficient. In the present study, estimation of the viscosity of the drilling mud with the Barite, Calcium Carbonate and Olivine were investigated by using artificial neural network. Spud type muds were prepared according to American Petroleum Institute (API) Spec. 13Astandart and then, these materials were added in different amounts (1-6 wt%). Rheological and filtration analysis of the muds were done according to American Petroleum Institute (API) standards. The developed neural network architecture is trained by the limited experimental data and the estimation performance of it is tested with the data not used in training. The results obtained from the viscometer and artificial neural network estimation were compared with each other and they showed sufficient agreement for viscosity estimation of drilling mud. It is observed that the average percentage error in estimation of the drilling mud viscosity was found to be less than 2%. According to the results, the designed artificial neural network structure has very successful prediction performance and it can say that ANN could be used with directly estimate the viscosity or other rheological parameters without any more experimental procedures after training the network with adequate samples.

High-entropy alloys (HEAs) with face-centered cubic (FCC) structures exhibit high toughness and corrosion resistance, but their average strengths and relatively low wear resistance can limit their engineering ap-plications. In this study, FCC Al0.07Co1.26Cr1.80Fe1.42Mn1.35Ni1.10 HEAs were boronized for 4 h at temperatures of 900, 950, and 1000 degrees C to form hard, protective metal borides on their surfaces. The microstructural characteristics of the borides formed were examined using X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The mechanical properties of the boride layers were studied by nanoindentation measurements, and the tribological performances of the layers were evaluated by ball-on -disk type wear tests in air, 3.5% NaCl and 5% H2SO4. Irrespective of the boronizing temperature, (Fe0.4Mn0.6) B, (Cr0.4Mn0.6)B, (CoFe)B2 and Cr2Ni3B6 phases were detected in the surfaces of the boronized samples. The surface hardnesses of the boronized samples reached nearly ten times the hardness of the as-cast HEA. The borides were effective in reducing friction as well as wear. Increasing the boronizing temperature increased the thicknesses of the coatings and further improved wear characteristics. Wear rates in 5% H2SO4 were generally higher than the wear rates in 3.5% NaCl, but the highest wear rates were observed in air. (c) 2021 Elsevier B.V. All rights reserved.

In this study, a novel fuzzy logic–based decision support system approach to provide assistance in the selection of suitable input shaping techniques is presented. The proposed approach selects the suitable input shaping technique for point-to-point motion type of systems such as precise positioning, crane operations, flexible robotic systems and so on. The problem solution addressed is the selection of the input shaping technique and the settings for the selection of the input shaper. Some of these design issues require extensive expertise in command shaping and system modeling studies. To overcome these problems and the necessity for such an expertise in these application areas, the proposed technique is provided as a solution. The presented study also provides a review of input shaping methods as well as their advantages and disadvantages in terms of vibration elimination performance, traveling time and robustness features. In the final section of the study, the details of the simulations, as well as experimental results, are provided to validate the achieved high performance of the proposed technique. The experimental studies are conducted on a Quanser IP02 Gantry Crane experimental setup.

Öz:Bu çalışmada top ve çubuk sistemi için kaskad PD+P kontrolcü katsayıları meta-sezgisel algoritmalar kullanılarak optimize edilmiştir. Laboratuvar ortamında birçok sistemin benzetiminin elde edilmesini sağlayan top ve çubuk sisteminin amacı çubuk üzerinde tek eksende serbest olarak hareket eden topun referans konuma ulaşması ve dengesinin sağlanmasıdır. Top ve çubuk sistemi hızlı ve yavaş dinamikleri aynı anda içinde barındırdığı için PD+P kaskad kontrolör tasarlanmıştır. Geleneksel kontrolcülere göre ayarlanması zor olan kaskad kontrolcü katsayıları Yapay Arı Kolonisi ve Öğretme Öğrenme Tabanlı Optimizasyon algoritmaları kullanılarak tayin edilmiştir. Uygulanan optimizasyonlarda IAE, ITAE, ISE, MSE amaç fonksiyonları ve yeni bir amaç fonksiyonu olan Birim Basamak Temelli (BB) amaç fonksiyonu önerilmiştir. Önerilen amaç fonksiyonu kullanılarak elde edilen kontrolcü cevaplarında topun istenilen referans konuma hiç aşım yapmadan ulaştığı görülmüştür., In this study, cascade PD+P controller gains for the ball and beam system are tuned using metaheuristic algorithms. The aim of the ball and beam system, which provides the simulation of many systems in the laboratory environment, is to reach the reference position and balance of the ball, which moves freely on a single axis on the beam. PD+P cascade controller which contained fast and slow dynamics at the same time is designed for the ball and beam system. Cascade controller gains, which are difficult to adjust compared to conventional controllers, are tuned using Artificial Bee Colony and Teaching Learning Based Optimization algorithms. In the optimizations applied, IAE, ITAE, ISE, MSE objective functions, and a new step response based objective function are proposed. In the controller responses obtained using the proposed objective function, the ball reached the desired reference position without overshoot.

The aim of this study is to develop inhibitive drilling fluid systems generated from waste materials that can contribute to the reduction of potential well instability problems caused by drilling fluid based on rheological and filtration properties. In this study, a comprehensive experimental work was carried out to assess suitability of fly ash and rice husk ash, which are quite a large amount of waste, in inhibitive water based-drilling fluids at ambient temperature. To this end, inhibitive drilling fluids systems were formulated with various concentrations (0, 1, 3, 5, 7, 9, 12.5, 15 (wt%)) of fly ash and rice husk ash with 0, 2, 4, 7, 9, 12.5, 15 (wt%) concentrations in the two type of inhibitive drilling fluid systems and combined use of fly ash and rice husk ash with their optimum concentrations determined was analyzed in the inhibitive drilling fluid in order to determine the drilling fluid with the most favorable characteristics based on rheological and filtration properties including apparent viscosity (AV), plastic viscosity (PV), yield point (YP), gel strength, fluid loss and mud cake thickness. In addition, grinding impact of fly ash particles in the inhibitive drilling fluid system was determined in the development of the drilling fluid by employing mechanically ground fly ash for 30, 60 and 120 min in a tumbling ball mill. Finally, fly ash and rice husk ash were characterized based on X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Experimental results show that developed drilling fluids with fly ash and rice husk ash not only enhanced rheological properties but also improved the filtration properties by increasing the rheological parameters and decreasing fluid loss and mud cake thickness. With the developed drilling fluids, AV, YP and PV increased by 35%, 32%, 28%, respectively with fly ash for the 12.5 wt% concentration while the parameters increased by 19%, 27%, 14%, respectively with the 4 wt% rice husk ash. Gel strengths of the fluids slightly increased compared to reference fluid and were in acceptable range. On the other hand, developed drilling fluid resulted in a 10% and 12% reduction in fluid loss for fly ash and rice husk ash at 12.5 wt% and 4 wt% concentrations, respectively, as well as a 54% and 63% reduction in mud cake thickness. In addition, the results reveal that developed drilling fluid with sieved fly ash yielded superior flow behavior compared to drilling fluid formulated with ground forms of fly ash. Consequently, based on the study, non-damaging and inhibitive drilling fluid systems were developed by using waste material fly ash and rice husk ash, and hence enhancing performance of drilling operation as well as reducing the risk of amount of wastes disposed to the environment and the potential of issues such as formation damage, wellbore instability caused by drilling fluid and associated challenges.

WOS: 000514219200002, In this paper, we present a compilation of the measured photon-induced K-beta/K-alpha intensity ratio values published in the literature from 1969 to 2018. In the considered period, we found about 1118 values (127 papers) for elements with 11

WOS: 000524014100001, In this study, azobenzene and coumarin functionalized thiophene comprising two copolymers (poly (4-((3"'-hexyl-[2,2 ':5 ',2 '':5 '',2"'-tetrathiophene] - 3 '-yl)methoxy) - 2H-chromen-2-one (P1) and poly (1-(4-((4"'-hexyl-[2,2 ': 5 ', 2 '': 5 '', 2"' - tetrathiophene] - 3 '-yl) methoxy) phenyl) -2-phenyldiazene) (P2)), were designed and synthesized according to the donor-acceptor (D-A) approach to investigate their electrochemical, optical and photovoltaic behaviors. Among the various copolymerization methods to obtain P1 and P2, Stille copolymerization reaction was preferred. The HOMO and LUMO values were determined via cyclic voltammetry (CV) as -5.64 eV and -3.76 eV for P1 and -5.47 eV and -3.83 eV for P2, respectively. The optical band gaps of the polymers were calculated as 1.88 eV and 1.64 eV using UV-VIS spectrophotometer for P1 and P2. Electrochemical and spectroelectrochemical studies for synthesized copolymers support their usage in organic solar cell applications. The organic solar cells (OSCs) were designed using polymer as an electron donor group and PC60BM as an electron acceptor group. Performances of OSCs based on P1 and P2 were investigated with the device structure of ITO/PEDOT:PSS/Polymer(P1/P2):PC60BM/LiF/Al. The preliminary solar cell results were reported here and studies are going on in our laboratories to increase the efficiency. The highest power conversion efficiency was obtained as 0.81% for P1 based device with 0.47 V open-circuit voltage (V-oc) and 4.92 mA/cm(2) current density (J(sc)) values. The highest efficiency for P2 comprising device was found to be 0.96% under optimum conditions with 0.60 V and 4.98 mA/cm(2), V-oc and J(sc) values, respectively.