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Articles 5521 - 5550 of 10319
Full-Text Articles in Physical Sciences and Mathematics
A Mobile And Web Application-Based Recommendation System Using Color Quantization And Collaborative Filtering, Fi̇dan Kaya, Gürel Yildiz, Adnan Kavak
A Mobile And Web Application-Based Recommendation System Using Color Quantization And Collaborative Filtering, Fi̇dan Kaya, Gürel Yildiz, Adnan Kavak
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a recommendation system based on a mobile and web application is proposed for indoor decoration. The main contribution of this work is to apply two-stage filtering using linear matching and collaborative filtering to make recommendations. In the mobile application part, the image of the medium captured by a mobile phone is analyzed using color quantization methods, and these color analysis results along with other user-defined parameters such as height, width, and type of the product are sent to the web server. In the web application part, a large data set is first filtered via linear matching in …
A Comparative Study Of Denoising Semg Signals, Ulvi̇ Başpinar, Volkan Yusuf Şenyürek, Bariş Doğan, Hüseyi̇n Selçuk Varol
A Comparative Study Of Denoising Semg Signals, Ulvi̇ Başpinar, Volkan Yusuf Şenyürek, Bariş Doğan, Hüseyi̇n Selçuk Varol
Turkish Journal of Electrical Engineering and Computer Sciences
Denoising of surface electromyography (sEMG) signals plays a vital role in sEMG-based mechatronics applications and diagnosis of muscular diseases. In this study, 3 different denoising methods of sEMG signals, empirical mode decomposition, discrete wavelet transform (DWT), and median filter, are examined. These methods are applied to 5 different levels of noise-added synthetic sEMG signals. For the DWT-based denoising technique, 40 different wavelet functions, 4 different threshold-selection-rules, and 2 threshold-methods are tested iteratively. Three different window-sized median filters are applied as well. The SNR values of denoised synthetic signals are calculated, and the results are used to select DWT and median …
Multilevel Hybrid Cascade-Stack Inverter With Substantial Reduction In Switches Number And Power Losses, Mahdi Toopchi Khosroshahi, Ali Ajami, Ata Ollah Mokhberdoran, Mohammadreza Jannati Oskuee
Multilevel Hybrid Cascade-Stack Inverter With Substantial Reduction In Switches Number And Power Losses, Mahdi Toopchi Khosroshahi, Ali Ajami, Ata Ollah Mokhberdoran, Mohammadreza Jannati Oskuee
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes a multilevel hybrid cascade-stack (HCS) converter. Recently, different new topologies for cascade-type converters have been suggested with the goal of reducing switch number, loss, switch PIV, etc. Meanwhile, output voltage steps increase, and the number of switches is predominately reduced in the suggested inverter in comparison to conventional cascade converters. Additionally, a reduction in the number of on-state switches in the introduced topology causes power loss and voltage drop to decrease. Firstly, the fundamental parts of inverter configuration are described. Afterwards, symmetric and asymmetric converter types are discussed. Simulation and experimental results for 11- and 23-level symmetric …
A Fourth-Order Accurate Compact 2-D Fdfd Method For Waveguide Problems, Lokman Kuzu
A Fourth-Order Accurate Compact 2-D Fdfd Method For Waveguide Problems, Lokman Kuzu
Turkish Journal of Electrical Engineering and Computer Sciences
In this work, a fourth-order accurate 2-D finite difference frequency domain method is proposed for the analysis of general waveguide structures. Finite difference techniques have been extensively used to solve electromagnetic problems over the decades. These methods discretize the computational domain using the Yee cell, but the standard Yee scheme used in these methods is only second-order accurate. In order to demonstrate the advantages of the proposed scheme compared to the multiresolution frequency domain method and the traditional 2-D finite difference frequency domain scheme, the dispersion characteristics of various waveguide structures are analyzed.
Impact Of Repeaters On The Performance Of Indoor Visible Light Communications, Refi̇k Çağlar Kizilirmak
Impact Of Repeaters On The Performance Of Indoor Visible Light Communications, Refi̇k Çağlar Kizilirmak
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, we examine the performance of fixed gain amplify-and-forward repeaters for visible light communication (VLC) systems. We present the wireless optical channel model for VLC with the repeater and we evaluate the bit-error-rate (BER) performance for pulse-position modulation over the multipath channel with additive white Gaussian noise. The results reveal that when a repeater is placed, both the BER and the illuminance performance can be improved at any location in a typical office space. The benefit of VLC repeaters is also discussed when the channel from the source to the destination is shadowed. It is found that when …
Decode-And-Forward Relaying Based On Orthogonal Complementary Codes, Refi̇k Çağlar Kizilirmak
Decode-And-Forward Relaying Based On Orthogonal Complementary Codes, Refi̇k Çağlar Kizilirmak
Turkish Journal of Electrical Engineering and Computer Sciences
In this note, we propose a full-duplex decode-and-forward cooperative diversity scheme based on code division with orthogonal complementary codes. We consider a simple case in which a single user is assisted by a single relay to achieve cooperative diversity. When the cooperation is full-duplex, the operational delay of the relay makes the channel asynchronous and this may cause multiple-access interference (MAI) between the user and relay. The orthogonal complementary codes have perfect autocorrelation and cross-correlation properties that provide MAI-free operation in asynchronous channels. In the proposed scheme, the user and relay terminals spread their messages with complementary codes and the …
Regulation Of Methane Gas Output From An Anaerobic Reactor System Using Moving Horizon $H_{\Infty }$ Control, Fatma Yildiz Taşcikaraoğlu, Şeref Naci̇ Engi̇n
Regulation Of Methane Gas Output From An Anaerobic Reactor System Using Moving Horizon $H_{\Infty }$ Control, Fatma Yildiz Taşcikaraoğlu, Şeref Naci̇ Engi̇n
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, the moving horizon $\mathcal{H}_{\infty }$\textbf{ }control used for tracking a desired methane gas output from an anaerobic wastewater treatment reactor is compared with classical $\mathcal{H}_{\infty }$ control and a proportional-integral-derivative controller. The nonlinear system is first linearized around the set of equilibrium and operating points selected, and then the linear matrix inequalities required to comply with the constraints and guarantee the stability are constructed. Finally, the experimental results are obtained by implementing the control method in a MATLAB environment. It is concluded that moving horizon $\mathcal{H}_{\infty }$ control yields satisfactory results.
Capacitive Sensor Supporting Multiple Touch Switches Using A Resistor String, Kwangsu Seong
Capacitive Sensor Supporting Multiple Touch Switches Using A Resistor String, Kwangsu Seong
Turkish Journal of Electrical Engineering and Computer Sciences
In a low-cost integrated circuit (IC) chip, the packaging cost is a considerable portion of the total manufacturing cost of the chip. As the packaging cost is directly related to the total number of I/O pins, it is highly desirable to minimize the number of I/O pins while maintaining the same functionality. We propose a capacitive sensor that supports multiple touch switches with only two IC pins. The electrode plates of the touch switches are placed at the ends of a resistor string and between every two adjacent resistors in the resistor string. The proposed method measures rise times at …
Effective Cooperative Dtv Detection Using The Goertzel Algorithm, Selman Kulaç, Murat Hüsnü Sazli
Effective Cooperative Dtv Detection Using The Goertzel Algorithm, Selman Kulaç, Murat Hüsnü Sazli
Turkish Journal of Electrical Engineering and Computer Sciences
In digital TV (DTV) detection, to monitor the DTV spectrum, only pilot tone frequency values can be observed in order to achieve calculation and energy savings. These savings can be achieved using the Goertzel algorithm. However, more than one receiver sensor is needed in order to increase the detection quality. In this technique, the Goertzel algorithm is used for energy-efficient pilot tone detection and a new effective cooperative structure is proposed. There is no extra fusion center and more than one DTV band can be monitored with this OR rule-based cooperative structure. With this new cooperative structure, reaching the desired …
Study Of Mac Routing In The Bplc P1901 Access Network: Fixed Vs. Adaptive Approach, Asmir Gogic, Aljo Mujcic, İsmai̇l Hakki Çavdar, Matej Zajc, Nermin Suljanovic
Study Of Mac Routing In The Bplc P1901 Access Network: Fixed Vs. Adaptive Approach, Asmir Gogic, Aljo Mujcic, İsmai̇l Hakki Çavdar, Matej Zajc, Nermin Suljanovic
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper we propose an improved adaptive media access (MAC) layer routing algorithm for the broadband power line communication (BPLC) access network founded on the fixed basic approach routing algorithm, which is integrated within the IEEE P1901 standard. The proposed adaptive algorithm incorporates a new dynamically scaled threshold for the selection of the next hop station based on the information from the physical layer. Furthermore, the procedures for the route and the time allocation modifications during the connection setup and later adjustments are developed. Simulation of the new adaptive and existing fixed routing algorithm is performed on the model …
An Implementable Approach In Order To Model A Nonideal Incremental Encoder In Speed Measurement Studies, Mahdi Maaref, Alireza Rezazadeh
An Implementable Approach In Order To Model A Nonideal Incremental Encoder In Speed Measurement Studies, Mahdi Maaref, Alireza Rezazadeh
Turkish Journal of Electrical Engineering and Computer Sciences
Incremental encoders have attracted significant attention to measure motor speed worldwide. Due to the advantages of incremental encoders a noticeable percentage of Servo system drives have been built based on these sensors. The nonideality of encoders, especially mechanical misalignments, is one of their most important problems, affecting the precision of calculations. In the current paper we present an analytical formula to model the nonideal incremental encoder and calculate both the frequency and magnitude of vibrations due to this nonideality. Moreover, a nonideality identity parameter of the encoder is defined. This parameter can be used for quality assurance purposes. Moreover, it …
Fuzzy Sliding Mode Control Applied To A Doubly Fed Induction Generator For Wind Turbines, Sid Ahmed El Mehdi Ardjoun, Mohamed Abid
Fuzzy Sliding Mode Control Applied To A Doubly Fed Induction Generator For Wind Turbines, Sid Ahmed El Mehdi Ardjoun, Mohamed Abid
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper an indirect vector control using fuzzy sliding mode control is proposed for a double-fed induction generator (DFIG), applied for a wind energy conversion system in variable speed. The objective is to independently control the active and reactive power generated by the DFIG, which is decoupled by the orientation of the flux. The sliding mode control finds its strongest justification for the problem concerning the use of a robust nonlinear control law for the model uncertainties. As far as the fuzzy mode control is concerned, it aims at reducing the chattering effect. The obtained results show the increasing …
An Improved Incremental Conductance Based Mppt Approach For Pv Modules, Mustafa Engi̇n Başoğlu, Beki̇r Çakir
An Improved Incremental Conductance Based Mppt Approach For Pv Modules, Mustafa Engi̇n Başoğlu, Beki̇r Çakir
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a new maximum power point tracking (MPPT) method based on an incremental conductance (IC) algorithm, constant voltage, and look-up table approach. Convergence time, one of the indicators of MPPT quality, is considered for improving MPPT performance of photovoltaic (PV) modules. In this context, a novel hybrid MPPT approach has been proposed. This proposed method consists of three stages. In the first stage, the value of load resistance is calculated. Then the initial operation point of the PV module is determined by using the constant voltage method or look-up table approach. An IC algorithm is used in order …
An Economic And Environmental Analysis Of Biomass-Solar Hybrid System For The Textile Industry In India, Mahalakshmi Mahadevan, Latha Salai
An Economic And Environmental Analysis Of Biomass-Solar Hybrid System For The Textile Industry In India, Mahalakshmi Mahadevan, Latha Salai
Turkish Journal of Electrical Engineering and Computer Sciences
This paper focuses on the design and analysis of a hybrid biomass-solar photovoltaic system for the textile industry with the goal of minimizing the cost and greenhouse gas emissions. The feasibility analysis of the hybrid system is performed based on the resource availability and the power generation potential of the existing biomass power plant near the textile plant at T.Kallupatti in Tamil Nadu, India. The power plant located at the site (9.66$^{\circ}$N, 77.79$^{\circ}$E) has an average daily global horizontal irradiance of 4.86 kWh/m$^{2}$, which has been validated through NASA Surface Meteorology and Solar Energy data. The chosen site also has …
Impact Of Large-Scale Installation Of Led Lamps In A Distribution System, Sohel Uddin, Hussain Sharef, Olav Krause, Azah Mohamed, Mohammad Abdul Hannan, Naz Niamul Islam
Impact Of Large-Scale Installation Of Led Lamps In A Distribution System, Sohel Uddin, Hussain Sharef, Olav Krause, Azah Mohamed, Mohammad Abdul Hannan, Naz Niamul Islam
Turkish Journal of Electrical Engineering and Computer Sciences
The aim of this paper was to examine the utilization of a large number of nonlinear light emitting diode (LED) lamps in a distribution system and its impact on system power quality. Initially, harmonic and others electrical characteristics were identified by carrying out an experiment on four types of LED lamps available on the local market. On the basis of the identified characteristics, a new LED lamp model was developed in MATLAB Simulink. This model is called the time-dependent current source model and gives more accurate results than the fixed current source model. Then this model was applied to a …
Performance Analysis Of A 500-Kwp Grid-Connected Solar Photovoltaic Power Plant In Kahramanmaraş, Şaban Yilmaz, Hasan Riza Özçalik
Performance Analysis Of A 500-Kwp Grid-Connected Solar Photovoltaic Power Plant In Kahramanmaraş, Şaban Yilmaz, Hasan Riza Özçalik
Turkish Journal of Electrical Engineering and Computer Sciences
In today's world, the daily need for and cost of energy sources increase and this forces industrial institutions to seek for new ways to generate their own energy. The developments in photovoltaic systems have recently drawn attention in the business world. Although their installation costs are high, they are environmentally friendly and profitable investments in the long run. The cost analysis of a large-scale photovoltaic generator in the climatic conditions of Kahramanmara\c{s} will lead the way to new investments. In this study, the modeling and cost analysis of an on-grid photovoltaic generator of 500 kW, which was installed to provide …
New Three-Dimensional Space Vector Pulse Width Modulation Of Pv-Af System Based On The Gh$\Gamma $ Coordinate System, Juan Zhou, Malong Liu, Chen Wei, Chaoxu Gao, Xiaojie Wu
New Three-Dimensional Space Vector Pulse Width Modulation Of Pv-Af System Based On The Gh$\Gamma $ Coordinate System, Juan Zhou, Malong Liu, Chen Wei, Chaoxu Gao, Xiaojie Wu
Turkish Journal of Electrical Engineering and Computer Sciences
The photovoltaic power generation and active filter (PV-AF) system can realize photovoltaic grid-connected power regulation, and meanwhile it can also improve the power quality of power grid effectively. The four-leg grid-connected inverter has successfully been used in the three-phase four-wire system. In this paper, a three-dimensional space vector pulse width modulation (3D-SVPWM) method based on the gh$\gamma $ coordinate system for a four-leg inverter has been proposed. As the switching vectors of the four-leg inverter are in the three-dimensional space, it is difficult to realize the complex modulation process. In order to simplify the modulation process, the reference vector is …
Lattice Approach To Video Steganography, Onur Ünlü, Hacer Karacan
Lattice Approach To Video Steganography, Onur Ünlü, Hacer Karacan
Turkish Journal of Electrical Engineering and Computer Sciences
As a result of the continuously increasing amount of important data, the demand for information security increases daily. Steganographic techniques can play a considerable role in solving this issue, since they can hide the necessary data. Generally, audio and image files have been utilized as hiding media in this area. However, because of their limited capacity, these media limit the amount of hidden information. On the other hand, the capacity limit can be exceeded by applying steganography on video files. There are few studies on video steganography in the literature. In this study, a steganographic library, which is independent of …
A Comparative Study Of Two Different Fpga-Based Arrhythmia Classifier Architectures, Ahmet Turan Özdemi̇r, Kenan Danişman
A Comparative Study Of Two Different Fpga-Based Arrhythmia Classifier Architectures, Ahmet Turan Özdemi̇r, Kenan Danişman
Turkish Journal of Electrical Engineering and Computer Sciences
Early diagnosis of dangerous heart conditions is very important for the treatment of heart diseases and for the prevention of sudden cardiac death. Automatic electrocardiogram (ECG) arrhythmia classifiers are essential to timely diagnosis. However, most of the medical diagnosis systems proposed in the literature are software-based. This work focused on the hardware implementation of a mobile artificial neural network (ANN)-based arrhythmia classifier that is implemented on a field programmable gate array (FPGA) as a single chip solution, as an alternative to various software models of ANNs. Due to the parallel nature of ANNs, hardware implementation of ANNs needs a large …
Assessment Of Vehicular Transportation Quality Via Smartphones, Ahmet Alper Teci̇mer, Zi̇ya Ci̇han Tayşi̇, Ali̇ Gökhan Yavuz, Mi̇ne Eli̇f Karsligi̇l Yavuz
Assessment Of Vehicular Transportation Quality Via Smartphones, Ahmet Alper Teci̇mer, Zi̇ya Ci̇han Tayşi̇, Ali̇ Gökhan Yavuz, Mi̇ne Eli̇f Karsligi̇l Yavuz
Turkish Journal of Electrical Engineering and Computer Sciences
Despite alternative transportation opportunities, road transportation still occupies an important part of our daily lives. Ever-advancing technological developments set high expectations of vehicular comfort and safety. Thus, it is necessary to develop systems that are able to detect and classify events related to the comfort and safety of vehicular transportation. Researchers have proposed several systems to monitor the quality of vehicular transportation. However, most of these systems are only capable of monitoring either road conditions or driving behaviors. Also, many of them are not easily applicable in real life because of special installation requirements and maintenance procedures with highly specialized …
Dual Open-End Stator Winding Induction Machine Fed By Redundant Voltage Source Inverters, Sami Guizani, Faouzi Ben Ammar
Dual Open-End Stator Winding Induction Machine Fed By Redundant Voltage Source Inverters, Sami Guizani, Faouzi Ben Ammar
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, the authors propose the availability analysis of a dual open-end stator windings asynchronous machine. Each open-end stator winding is supplied by two PWM voltage source inverters. The active and passive redundancy of the inverters improves reliability, availability, and safety of the system since the loss of inverter losses does not stop the machine. Indeed, for active redundancy, in the case of failure of the inverter, the corresponding winding is disconnected and the other winding is supplied by the two healthy inverters. For passive redundancy, one winding is fed by two inverters and the two others are waiting; …
A Novel Efficient Model For The Power Flow Analysis Of Power Systems, Amir Safdarian, Mahmud Fotuhi Firuzabad, Farrokh Aminifar
A Novel Efficient Model For The Power Flow Analysis Of Power Systems, Amir Safdarian, Mahmud Fotuhi Firuzabad, Farrokh Aminifar
Turkish Journal of Electrical Engineering and Computer Sciences
The overall system status calculated by power flow analysis is the most basic information used for all decisions taken by power system operators and planners. While conventional AC power flow solutions are computationally tractable, approximate DC models are employed in many applications, such as optimal power flow studies and unit commitment problems, mainly due to the linear nature of DC models. These models do not provide any information on the reactive power and voltage magnitude quantities and occasionally inaccurate results of the active power values. This paper presents an efficient power flow approach compromising both the conflicting aspects of speed …
A New Systematic And Flexible Method For Developing Hierarchical Decision-Making Models, Ulaş Beldek, Mehmet Kemal Leblebi̇ci̇oğlu
A New Systematic And Flexible Method For Developing Hierarchical Decision-Making Models, Ulaş Beldek, Mehmet Kemal Leblebi̇ci̇oğlu
Turkish Journal of Electrical Engineering and Computer Sciences
The common practice in multilevel decision-making (DM) systems is to achieve the final decision by going through a finite number of DM levels. In this study, a new multilevel DM model is proposed. This model is called the hierarchical DM (HDM) model and it is supposed to provide a flexible way of interaction and information flow between the consecutive levels that allows policy changes in DM procedures if necessary. In the model, in the early levels, there are primary agents that perform DM tasks. As the levels increase, the information associated with these agents is combined through suitable processes and …
Electrochemical Monitoring Of The Interaction Between Mitomycin C And Dna At Chitosan--Carbon Nanotube Composite Modified Electrodes, Pembe Ece Canavar, Ece Ekşi̇n, Kadri̇ye Arzum Erdem Gürsan
Electrochemical Monitoring Of The Interaction Between Mitomycin C And Dna At Chitosan--Carbon Nanotube Composite Modified Electrodes, Pembe Ece Canavar, Ece Ekşi̇n, Kadri̇ye Arzum Erdem Gürsan
Turkish Journal of Chemistry
Single-walled carbon nanotube (CNT) and chitosan composite (chitosan*CNT) based sensors were developed as DNA biosensors, and then they were applied for electrochemical investigation of the interaction between the anticancer drug mitomycin C (MC) and DNA. The oxidation signals of MC and guanine were monitored before and after the interaction process by differential pulse voltammetry (DPV). The DPV results were in good agreement with those of electrochemical impedance spectroscopy (EIS). Analytical parameters such as DNA concentration, MC concentration, and MC interaction time with DNA were optimized. The detection limits were 6.85 \mu g/mL for DNA and 11.01 \mu g/mL for MC.
Kinetics And Performance Studies Of A Switchable Solvent Tmg (1,1,3,3-Tetramethylguanidine)/1-Propanol/Carbon Dioxide System, Özge Yüksel, Mustafa Çağdaş Öztürk, Ayça Şeker, Erdoğan Alper
Kinetics And Performance Studies Of A Switchable Solvent Tmg (1,1,3,3-Tetramethylguanidine)/1-Propanol/Carbon Dioxide System, Özge Yüksel, Mustafa Çağdaş Öztürk, Ayça Şeker, Erdoğan Alper
Turkish Journal of Chemistry
The rate constants and the activation energies of the reaction between carbon dioxide and 1,1,3,3-tetramethylguanidine (TMG) in 1-propanol solution were measured by a stopped-flow technique at a temperature range of 288--308 K and at a TMG concentration range of 2.5--10.0 wt %. Based on the pseudo-first-order reaction for CO_2, the reaction was modeled by a termolecular reaction mechanism, which resulted in a rate constant of 199.30 m^3 kmol^{-1} s^{-1} at 298 K. The activation energies were 5.19 kJ/mol and 5.26 kJ/mol at 2.5 and 5.0 wt % TMG, respectively. In addition, carbon dioxide absorption capacity was investigated using a gas--liquid …
Dual Effect Of Coumarin Benzimidazolium Ionic Salt Covalently Bonded On A Silica Network, Ahmet Gültek, Davut Aksüt, Turgay Seçki̇n, Emre Bi̇rhanli, Mert Olgun Karataş, Bülent Alici
Dual Effect Of Coumarin Benzimidazolium Ionic Salt Covalently Bonded On A Silica Network, Ahmet Gültek, Davut Aksüt, Turgay Seçki̇n, Emre Bi̇rhanli, Mert Olgun Karataş, Bülent Alici
Turkish Journal of Chemistry
Synthesis of the ionic liquid 1-allyl-3-(4-methyl-7,8-dihydroxy-2H-chromen-2-one) benzimidazolium chloride followed by the conversion of ammonium salts on the imidazole ring hooked to the coumarin group was modified by postmodification of the silica matrix where 3-chloropropyltrimethoxysilane was used as not only a surface modification agent, but also as an ATRP halogen source. The synergetic effect of charged ammonium groups as well as hydroxyl groups present on the coumarin was investigated in terms of ATRP polymerization. The results confirmed that brush polymers show outstanding antibacterial effects against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa.
Synthesis And Evaluation Of Antioxidant Activities Of Novel 1,3,4-Oxadiazole And Imine Containing 1h-Benzimidazoles, Ayşe Selen Alp, Gülgün Kilcigi̇l, Elçi̇n Deni̇z Özdamar, Tülay Çoban, Bi̇nay Eke
Synthesis And Evaluation Of Antioxidant Activities Of Novel 1,3,4-Oxadiazole And Imine Containing 1h-Benzimidazoles, Ayşe Selen Alp, Gülgün Kilcigi̇l, Elçi̇n Deni̇z Özdamar, Tülay Çoban, Bi̇nay Eke
Turkish Journal of Chemistry
Some novel 2-(substitutedbenzylthio)-5-((2-(4-substitutedphenyl)-1H-benzo[d]imidazol-1-yl)methyl)-1,3,4-oxadiazoles (5--12) and 2-(2-(4-chlorophenyl)-1H-benzo[d]imidazol-1-yl)-N'-(arylmethylene)acetohydrazide derivatives (13--22) were prepared and their in vitro antioxidant properties were investigated by determination of rat liver microsomal NADPH-dependent inhibition of lipid peroxidation (LP) levels and microsomal ethoxyresorufin O-deethylase (EROD) activity. Compound 18 was found to be the most active compound with 100% inhibition on LP level and 92% inhibition on EROD. Compounds 4b, 17, and 19 showed the strongest inhibitory effect (97%) on EROD. The free radical scavenging capacities of the compounds were also tested in vitro determining the interaction of the stable free radical 2,2,diphenyl-1-picrylhydrazyl (DPPH), and compounds 4a and 4b exhibited …
Reduction Behavior Of Fenoxaprop-P-Ethyl And Its Voltammetric Determination, Zeki̇ Eş, İbrahi̇m Hüdai̇ Taşdemi̇r
Reduction Behavior Of Fenoxaprop-P-Ethyl And Its Voltammetric Determination, Zeki̇ Eş, İbrahi̇m Hüdai̇ Taşdemi̇r
Turkish Journal of Chemistry
The reduction behavior of fenoxaprop-p-ethyl (FNX) was studied on a hanging mercury drop electrode. FNX showed 2 reduction peaks at about --0.7 V and at about --0.9 V versus Ag/AgCl/3.0 M KCl in Britton--Robinson buffer at pH 4.8. Both reductions were irreversible and adsorption was effective. The reduction peaks were assigned to the reduction of C=N to CH--NH and the reduction of C=O to CH--OH. Square-wave voltammetry has been proposed and validated for quantification of FNX in different samples. The linear working range was established as 0.30--15.0 \mu M. Limit of detection and limit of quantification were calculated as 0.07 …
Effect Of Acrylic Acid Feed Contents Of Microgels On Catalytic Activity Of Silver Nanoparticles Fabricated Hybrid Microgels, Zahoor Hussain Farooqi, Shanza Rauf Khan, Robina Begum, Farah Kanwal, Ahsan Sharif, Ejaz Ahmed, Shumaila Majeed, Kiran Ejaz, Aysha Ijaz
Effect Of Acrylic Acid Feed Contents Of Microgels On Catalytic Activity Of Silver Nanoparticles Fabricated Hybrid Microgels, Zahoor Hussain Farooqi, Shanza Rauf Khan, Robina Begum, Farah Kanwal, Ahsan Sharif, Ejaz Ahmed, Shumaila Majeed, Kiran Ejaz, Aysha Ijaz
Turkish Journal of Chemistry
We synthesized poly(N-isopropylacrylamide-co-acrylic acid) microgels with 1, 3, 5, and 7 mol percentage of acrylic acid. Silver nanoparticles were fabricated inside these microgels at room temperature. Pure microgels were characterized by Fourier transform infrared (FTIR) spectroscopy and dynamic light scattering (DLS). Hybrid microgels were characterized by UV-Visible spectroscopy. The size of the silver nanoparticles increased with an increase in the content of acrylic acid. Catalytic activity of these hybrid microgels was investigated using UV-Visible spectrophotometry. Induction time decreased from 8.8 to 2.6 min and the value of apparent rate constant decreased from 0.226 to 0.109 min^{-1}, when the content of …
Synthesis Of Tetrahydropyrimidinium Salts And Their In Situ Catalytic Activities Towards The Buchwald--Hartwig Amination Reaction Under Microwave Irradiation, Liangru Yang, Huanyu Bian, Wenpeng Mai, Pu Mao, Yongmei Xiao, Dong Wei, Lingbo Qu
Synthesis Of Tetrahydropyrimidinium Salts And Their In Situ Catalytic Activities Towards The Buchwald--Hartwig Amination Reaction Under Microwave Irradiation, Liangru Yang, Huanyu Bian, Wenpeng Mai, Pu Mao, Yongmei Xiao, Dong Wei, Lingbo Qu
Turkish Journal of Chemistry
A series of asymmetrical substituted tetrahydropyrimidinium salts and different kinds of bridged bis-tetrahydropyrimidinium salts were prepared through the quaterization of tetrahydropyrimidine or the dehydrogenation of hexahydropyrimidine. They were characterized and used as NHC precursors in the palladium catalyzed Buchwald--Hartwig amination reaction. The in situ formed catalytic system Pd(OAc)_2/tetrahydropyrimidinium and ^tBuOK catalyzed the amination of heteroaryl halides and heterocyclic amines effectively, producing the heterocyclic amine functionalized heteroaryl derivatives in high yields.