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Articles 4921 - 4950 of 10319
Full-Text Articles in Physical Sciences and Mathematics
Enhanced Delivery Of Epirubicin By Polyoxometalate-Based Magnetic Nanocarriers: Controlled Drug Loading And Ph-Sensitive Drug Release, Ezzat Rafiee, Nasibeh Rahpeyma
Enhanced Delivery Of Epirubicin By Polyoxometalate-Based Magnetic Nanocarriers: Controlled Drug Loading And Ph-Sensitive Drug Release, Ezzat Rafiee, Nasibeh Rahpeyma
Turkish Journal of Chemistry
A series of polyoxometalate-based magnetic nanoparticles were developed as novel carriers for anticancer drugs. Characterization of the nanoparticles was done by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), wavelength dispersive X-ray (WDX), and laser particle size analyzer. Epirubicin (EPI) was selected as a model drug. EPI loading efficiency, EPI loading content, and EPI release profiles were studied. Drug loading was controlled using acid-base titration since H$^{+}$ was released during the loading process. Based on these investigations, an efficient EPI delivery system was introduced. It showed high EPI-loading capacity (35.2 wt.{\%}) and high EPI loading …
Oxidative Dehydrogenation Of Propane Over V$_{2}$O$_{5}$ And K$_{2}$O-V$_{2}$O$_{5}$ Impregnated Mgal$_{2}$O$_{4}$Catalysts, Serkan Naci̇ Koç, Kübra Dayioğlu, Hasan Özdemi̇r
Oxidative Dehydrogenation Of Propane Over V$_{2}$O$_{5}$ And K$_{2}$O-V$_{2}$O$_{5}$ Impregnated Mgal$_{2}$O$_{4}$Catalysts, Serkan Naci̇ Koç, Kübra Dayioğlu, Hasan Özdemi̇r
Turkish Journal of Chemistry
V$_{2}$O$_{5}$ and K$_{2}$O-V$_{2}$O$_{5}$ impregnated MgAl$_{2}$O$_{4}$ catalysts were prepared and tested for the oxidative dehydrogenation of propane. The as-synthesized catalysts were characterized by using the XRD, BET, NH$_{3}$-TPD, TPR, and XPS methods. The catalytic tests were performed in a fixed bed tubular quartz reactor system between 450 and 550 $^{\circ}$C. It was observed that the conversion of propane increased but hydrocarbon selectivity decreased with increasing temperature over the V$_{2}$O$_{5}$/MgAl$_{2}$O$_{4}$ catalysts. The BET surface area values and surface acidities decreased upon potassium addition for the K-V$_{2}$O$_{5}$/MgAl$_{2}$O$_{4}$ catalysts, which resulted in a drastic drop in the conversion values obtained. The propylene and total …
Photocatalysis Of Formaldehyde In The Aqueous Phase Over Zno/Diatomite Nanocomposite, Reza Darvishi Cheshmeh Soltani, Alireza Khataee, Masumeh Mashayekhi, Mahdi Safari
Photocatalysis Of Formaldehyde In The Aqueous Phase Over Zno/Diatomite Nanocomposite, Reza Darvishi Cheshmeh Soltani, Alireza Khataee, Masumeh Mashayekhi, Mahdi Safari
Turkish Journal of Chemistry
In the present study, ZnO nanostructures were synthesized and immobilized on the surface of diatomite via a simple sonochemical method for the photocatalytic degradation of formaldehyde in the aqueous phase. The characterization of as-prepared ZnO/diatomite nanocomposite was carried out by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The photocatalysis of formaldehyde was favored at neutral pH. At a ZnO to diatomite ratio of 0.3, increasing the photocatalyst dosage from 0.2 to 1.5 g/L resulted in increasing the photocatalytic removal of formaldehyde from 37.51% to 88.05%. At a formaldehyde concentration of 100 mg/L, …
Ecofriendly One-Pot Synthesis And Antiviral Evaluation Of Novel Pyrazolyl Pyrazolines Of Medicinal Interest, Sobhi Gomha, Magda Abdalla, Mohamad Abd El-Aziz, Nany Serag
Ecofriendly One-Pot Synthesis And Antiviral Evaluation Of Novel Pyrazolyl Pyrazolines Of Medicinal Interest, Sobhi Gomha, Magda Abdalla, Mohamad Abd El-Aziz, Nany Serag
Turkish Journal of Chemistry
Ethyl 3-acetyl-1,5-diphenyl-1$H$-pyrazole-4-carboxylate reacts with a variety of arylaldehydes by grinding method in the presence of a catalytic amount of sodium hydroxide at ambient temperature to give the respective chalcones. The latter compounds react also by grinding method with nitrogen nucleophiles such as hydrazine hydrate, phenylhydrazine, and thiosemicarbazide to afford the corresponding pyrazol-3-yl pyrazolines. A series of 6-pyrazolylpyrimidine-2-thione derivatives were prepared by reaction of the above chalcones with thiourea by grinding method in the presence of a catalytic amount of sodium hydroxide at room temperature. In addition, 7-pyrazolylpyridopyrimidine-3-thione was prepared by reaction of chalcone with 6-aminothiouracil. All the newly synthesized compounds …
Prostereoisomerism And Biological Activity: Possible Implications For Drug Design, Sosale Chandrasekhar
Prostereoisomerism And Biological Activity: Possible Implications For Drug Design, Sosale Chandrasekhar
Turkish Journal of Chemistry
Prostereoisomerism (PIM), representing a subgroup within the achiral class of molecules, is manifested in a chiral environment. Although this is regardless of the orientation of the prostereoisomeric (PIC) molecule, PIM is manifested most emphatically in relation to a chiral surface (`two-dimensional chirality'). Then PIM is tantamount to `de facto chirality' as attachment of the PIC molecule to the surface leads to diastereomeric possibilities (cf. Ogston's hypothesis). Furthermore, the formation of host--guest complexes requires a steric complementarity between the component molecules. The fact that the weak dispersive forces involved therein require an optimum distance implies a `snugness of fit' criterion. This …
Synthesis Of Novel Thiazolylpyrazoline Derivatives And Evaluation Of Their Antimicrobial Activities And Cytotoxicities, Aouatef Tabbi, Zafer Asim Kaplancikli, Dahmane Tebbani, Leyla Yurttaş, Zerri̇n Cantürk, Özlem Atli, Merve Baysal, Gülhan Turan Zitouni
Synthesis Of Novel Thiazolylpyrazoline Derivatives And Evaluation Of Their Antimicrobial Activities And Cytotoxicities, Aouatef Tabbi, Zafer Asim Kaplancikli, Dahmane Tebbani, Leyla Yurttaş, Zerri̇n Cantürk, Özlem Atli, Merve Baysal, Gülhan Turan Zitouni
Turkish Journal of Chemistry
Several novel thiazolylpyrazoline derivatives were synthesized by reacting substituted 3,5-diaryl-1-thiocarba\-moyl-2-pyrazolines with phenacylbromides. The structures of the synthesized compounds were confirmed by IR, $^{1}$H NMR, $^{13}$C NMR, and MS spectral data. Their antimicrobial activities against Staphylococcus aureus(ATCC-25923), Enterococcus faecalis} (ATCC-29212), Enterococcus faecalis (ATCC-51922), Listeria monocytogenes (ATCC-1911), Klebsiella pneumoniae (ATCC-700603), Pseudomonas aeruginosa (ATCC-27853), Escherichia coli (ATCC-35218), Escherichia coli (ATCC-25922), Candida albicans (ATCC-90028), Candida glabrata (ATCC-90030), Candida krusei (ATCC-6258), and Candida parapsilosis (ATCC-22019) were investigated. The compounds were also studied for their cytotoxic effects using a MTT assay. Compound 7c showed the highest antimicrobial activity, possessing the same potential as chloramphenicol against K. …
Ag(I) Complexes Of Benzimidazol-2-Ylidene Ligands: A Study Of Catalytic Efficiency Towards Three-Component Coupling Reactions, Rafet Kilinçarslan, Nai̇m Sadiç, Beki̇r Çeti̇nkaya
Ag(I) Complexes Of Benzimidazol-2-Ylidene Ligands: A Study Of Catalytic Efficiency Towards Three-Component Coupling Reactions, Rafet Kilinçarslan, Nai̇m Sadiç, Beki̇r Çeti̇nkaya
Turkish Journal of Chemistry
The $N$-heterocyclic carbene (NHC)--Ag(I) complexes 3a-c were synthesized from benzimidazolium chlorides (2a-c = NHC.HCl), incorporating benzyl derivatives and a 2-methoxyethyl group (a: $^{3}$N = 2,4,6-trimethylbenzyl; b: $^{3}$N = 2,3,5,6-tetramethylbenzyl; c: $^{3}$N = pentamethylbenzyl). The compounds were characterized by spectroscopic and elemental analyses. The synthesized NHC-Ag(I) complexes (3a-c) were tested as catalysts for the catalytic three-component coupling reaction of aldehyde, alkyne, and amine to propargylamines in various solvents. All complexes were active catalysts for catalytic three-component coupling reactions with good yields under neat and mild conditions (after 4 h, yields of up to 94%).
Adsorption Of Cellulase On Poly(2-Hydroxyethyl Methacrylate) Cryogels Containing Phenylalanine, Murat Yavuz, Oğuz Çakir, Zübeyde Baysal
Adsorption Of Cellulase On Poly(2-Hydroxyethyl Methacrylate) Cryogels Containing Phenylalanine, Murat Yavuz, Oğuz Çakir, Zübeyde Baysal
Turkish Journal of Chemistry
The aim of this study was to prepare a supermacroporous cryogel that can be used for the adsorption of cellulase. The macroporous cryogel of poly(2-hydroxyethyl methacrylate-N-methacryloyl-l-phenylalanine) [p(HEMA-MAPA)] was prepared by copolymerization of 2-hydroxyethyl methacrylate (HEMA) with a functional monomer of N-methacryloyl-l-phenylalanine (MAPA). The cryogel was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and swelling tests. The effects of several parameters such as medium pH, temperature, ionic strength, and flow rate on cellulase adsorption were also investigated. Maximum cellulase adsorption was observed at 25 $^{\circ}$C and pH 4.0. Furthermore, adsorbed cellulase was desorbed from the cryogel by using 1.0 …
Degradation Of Bisphenol-A Using A Sonophoto Fenton-Like Hybrid Process Over A Lafeo$_{3}$ Perovskite Catalyst And A Comparison Of Its Activity With That Of A Tio$_{2}$ Photocatalyst, Meral Dükkanci
Turkish Journal of Chemistry
Oxidation of bisphenol-A (BPA) was investigated using a sonophoto Fenton-like hybrid process under visible light irradiation in the presence of iron-containing perovskite LaFeO$_{3}$ catalysts. For this purpose, firstly the perovskite catalyst (LaFeO$_{3})$ was prepared by the sol-gel method and calcined at different temperatures (500, 700, and 800 $^{\circ}$C). The prepared catalysts were characterized using XRD, SEM, FTIR, nitrogen adsorption, UV-vis DRS, and ICP/OES measurements. Among the prepared catalysts the catalyst that was calcined at 500 $^{\circ}$C showed better catalytic activity with respect to degradation and chemical oxygen demand (COD) reduction (of 21.8% and 11.2%, respectively, after 3 h of reaction …
Synthesis Of New Hexahydro-1h-Isoindole-1,3(2h)-Dione Derivatives From 2-Ethyl/Phenyl-3a,4,7,7a-Tetrahydro-1h-Isoindole-1,3-(2h)-Dione, Ayşe Tan, Bi̇rgül Koç, Nurhan Ki̇shali, Ertan Şahi̇n, Yunus Kara
Synthesis Of New Hexahydro-1h-Isoindole-1,3(2h)-Dione Derivatives From 2-Ethyl/Phenyl-3a,4,7,7a-Tetrahydro-1h-Isoindole-1,3-(2h)-Dione, Ayşe Tan, Bi̇rgül Koç, Nurhan Ki̇shali, Ertan Şahi̇n, Yunus Kara
Turkish Journal of Chemistry
A new and appropriate synthesis for hexahydro-1H-isoindole-1,3(2H)-dione derivatives has been developed starting from 3-sulfolene. The epoxidation of 2-ethyl/phenyl-3a,4,7,7a-tetrahydro-1H-isoindole-1,3-(2H)-dione and then the opening of the epoxide with nucleophiles gave hexahydro-1H-isoindole-1,3(2H)-dione derivatives. Amino and triazole derivatives of hexahydro-1H-isoindole-1,3(2H)-dione were synthesized from the formed product by the opening reaction of the epoxide with sodium azide. Hydroxyl analogues were obtained from cis-hydroxylation of 2-ethyl/phenyl-3a,4,7,7a-tetrahydro-1H-isoindole-1,3-(2H)-dione. The hydroxyl groups were converted to acetate.
Speciation Of Trace Metals And Metalloids By Solid Phase Extraction With Spectrometric Detection: A Critical Review, Ali̇ Rehber Türker
Speciation Of Trace Metals And Metalloids By Solid Phase Extraction With Spectrometric Detection: A Critical Review, Ali̇ Rehber Türker
Turkish Journal of Chemistry
Considerable interest is continuing to be shown in the speciation of metals, metalloids, and organometals due to the dependence of their toxicity and mobility on their chemical form. This review focuses on the speciation analysis of metals, metalloids, and organometals by solid phase extraction before spectrometric detection, and all aspects of analytical speciation such as determination of oxidation states and organometallic compounds. Some applications of speciation of metals and metalloids are also presented and discussed in this review. Fractionation, which is used sometimes as speciation, and chromatographic detection are not discussed. This review covers approximately the last four years (2012-March …
Spectrophotometric Determination Of Mercury Using Vortex-Assisted Liquid-Liquid Microextraction, Tatiana Antolova, Serhii Zaruba, Jana Sandrejova, Livia Kocurova, Andriy B. Vishnikin, Yaroslav Bazel, Vasil Andruch, Ioseph S. Balogh
Spectrophotometric Determination Of Mercury Using Vortex-Assisted Liquid-Liquid Microextraction, Tatiana Antolova, Serhii Zaruba, Jana Sandrejova, Livia Kocurova, Andriy B. Vishnikin, Yaroslav Bazel, Vasil Andruch, Ioseph S. Balogh
Turkish Journal of Chemistry
A novel method for the determination of mercury(II) is suggested. The procedure is based on the formation of an ion associate between the bromide complex of Hg(II) and Astrazon Red 6B dye and vortex-assisted liquid-liquid microextraction of the ion associate formed, with subsequent spectrophotometric detection. The variables that affect the procedure, such as pH, the concentration of ligand and dye, the type and volume of extraction solvent, and the rate and time of vortex mixing, were optimized. Under optimum conditions (pH 2.0, 0.01 mol L$^{-1}$ KBr, 2 $\times $ 10$^{-4}$ mol L$^{-1}$ AR6B, 50 $\mu $L of the extraction mixture …
Preparation Of Fe$_{3}$O$_{4}$ @ Montmorillonite Composite As An Effective Sorbent For The Removal Of Lead And Cadmium From Wastewater Samples, Hande Tinas, Ece Çalişkan, Ni̇l Özbek, Süleyman Akman
Preparation Of Fe$_{3}$O$_{4}$ @ Montmorillonite Composite As An Effective Sorbent For The Removal Of Lead And Cadmium From Wastewater Samples, Hande Tinas, Ece Çalişkan, Ni̇l Özbek, Süleyman Akman
Turkish Journal of Chemistry
A magnetic Fe$_{3}$O$_{4}$ @ montmorillonite composite was prepared and used for the separation of lead and cadmium from aqueous solutions. For this purpose, magnetite (Fe$_{3}$O$_{4})$ was generated by co-precipitation of FeSO$_{4}$ and FeCl$_{3}$ onto montmorillonite. The effects of various experimental parameters such as pH of the solution, amount of sorbent, initial concentration of analytes, and contact time on the sorption efficiencies of lead and cadmium ions were investigated and optimized by applying a batch technique. The concentrations of analytes were determined by high resolution continuum source flame atomic absorption spectrometry. The maximum adsorption occurred at pH 2.0. The adsorption capacity …
Analytical Capabilities Of Two-Phase Hollow-Fiber Liquid Phase Microextraction For Trace Multielement Determination In Aqueous Samples By Means Of Portable Total Reflection X-Ray Instrumentation, Eva Margui, Manuela Hidalgo
Analytical Capabilities Of Two-Phase Hollow-Fiber Liquid Phase Microextraction For Trace Multielement Determination In Aqueous Samples By Means Of Portable Total Reflection X-Ray Instrumentation, Eva Margui, Manuela Hidalgo
Turkish Journal of Chemistry
Liquid phase microextraction (LPME) procedures have been widely used in combination with atomic and emission spectroscopic techniques for the isolation and preconcentration of trace elements. However, its application in combination with total reflection X-ray spectrometry (TXRF) is still scarce. In this paper, we evaluate the possibilities and drawbacks of a two-phase hollow fiber LPME procedure in combination with TXRF for the simultaneous determination of trace amounts of Cr, Ni, Cu, Zn, Pb, and Cd in aqueous samples. After extraction of the analytes by using the optimum conditions (sample volume: 25 mL, complexing agent: APDC, organic solvent: hexylbenzene, extraction time: 2 …
Biosorption Potential Of Surface-Modified Waste Sugar Beet Pulp For The Removal Of Reactive Yellow 2 (Ry2) Anionic Dye, Si̇bel Tunali Akar, Sema Çeli̇k, Di̇lek Tunç, Yasemi̇n Yeti̇moğlu Balk, Tamer Akar
Biosorption Potential Of Surface-Modified Waste Sugar Beet Pulp For The Removal Of Reactive Yellow 2 (Ry2) Anionic Dye, Si̇bel Tunali Akar, Sema Çeli̇k, Di̇lek Tunç, Yasemi̇n Yeti̇moğlu Balk, Tamer Akar
Turkish Journal of Chemistry
Tetra-$n$-butylammonium bromide modified sugar beet pulp (TBAB-SBP) with good biosorption and regeneration potential was prepared for removal of dye from contaminated solutions. The decolorization performance of TBAB-SBP was investigated using Reactive Yellow 2 (RY2) as a model dye. The characterization of the modified biosorbent was investigated by IR, SEM, zeta potential, and BET surface area analysis to discuss the decolorization mechanism. The effects of initial pH, biosorbent amount, contact time, dye concentration, and flow rate on the treatment process were examined. The experimental kinetic data were well predicted by the pseudo-second-order kinetic model and Langmuir isotherm with a maximum monolayer …
Implementation Of A Modified Svpwm-Based Three-Phase Inverter With Reduced Switches Using A Single Dc Source For A Grid-Connected Pv System, Venkatesan Mani, Rajeswari Ramachandran, Deverajan Nanjundappan
Implementation Of A Modified Svpwm-Based Three-Phase Inverter With Reduced Switches Using A Single Dc Source For A Grid-Connected Pv System, Venkatesan Mani, Rajeswari Ramachandran, Deverajan Nanjundappan
Turkish Journal of Electrical Engineering and Computer Sciences
No abstract provided.
A Dynamic Spectrum Management Algorithm In Vdsl Systems, Sunil Sharma, Om Parkash Sahu
A Dynamic Spectrum Management Algorithm In Vdsl Systems, Sunil Sharma, Om Parkash Sahu
Turkish Journal of Electrical Engineering and Computer Sciences
A modified iterative water-filling algorithm is proposed in which power from only those subcarriers of the near end user are reduced, which has the worst effect on bit rates of far end users. The power back off from these subcarriers is done by reducing power spectral masks at respective subcarriers. The results after simulating the proposed algorithm give significant performance advantages in terms of data rate over the traditional iterative water-filling algorithm. These results approach the performance of highly complex optimal spectrum management algorithms while maintaining the complexity of the traditional iterative water-filling algorithm.
Suppression Of Interfering Ions By Using Ionic Liquid And Micelle Moieties In Spectrofluorimetric Analysis Of Manganese, Özlem Öter, Müge Aydin, Kadri̇ye Erteki̇n
Suppression Of Interfering Ions By Using Ionic Liquid And Micelle Moieties In Spectrofluorimetric Analysis Of Manganese, Özlem Öter, Müge Aydin, Kadri̇ye Erteki̇n
Turkish Journal of Chemistry
Eosin-Y exhibits high affinity and emission based spectral response to most of the major ions in water samples. In the present study we performed selective spectrofluorimetric analysis of manganese with eosin-Y in the presence of potential interferents. We employed green chemistry reagents, ionic liquids (ILs) and two different micelles, to suppress the effect of conventional cations and anions on the response of eosin-Y. The experimental data revealed that different test moieties caused enhanced analytical response to Mn$^{2+}$. The highest analytical signal of eosin-Y was obtained in the presence of Triton X-100 at a concentration of 2.0 $\times $ 10$^{-3}$ mol …
Investigation Of The Most Appropriate Mother Wavelet For Characterizing Imaginary Eeg Signals Used In Bci Systems, Önder Aydemi̇r, Temel Kayikçioğlu
Investigation Of The Most Appropriate Mother Wavelet For Characterizing Imaginary Eeg Signals Used In Bci Systems, Önder Aydemi̇r, Temel Kayikçioğlu
Turkish Journal of Electrical Engineering and Computer Sciences
Feature extraction is a very challenging task, since choosing discriminative features directly affects the recognition rate of the brain--computer interface (BCI) system. The objective of this paper is to investigate the effect of mother wavelets (MWs) on classification results. To this end, features were extracted from 3 different datasets using 12 MWs, and then the signals were classified using 3 classification algorithms, including k-nearest neighbor, support vector machine, and linear discriminant analysis. The experiments proved that Daubechies and Shannon were the most suitable wavelet families for extracting more discriminative features from imaginary EEG/ECoG signals.
Papr Reduction Using Genetic Algorithm In Lifting-Based Wavelet Packet Modulation Systems, Necmi̇ Taşpinar, Yüksel Tokur Bozkurt
Papr Reduction Using Genetic Algorithm In Lifting-Based Wavelet Packet Modulation Systems, Necmi̇ Taşpinar, Yüksel Tokur Bozkurt
Turkish Journal of Electrical Engineering and Computer Sciences
Wavelet packet modulation (WPM) is a potential candidate in wireless communication systems by virtue of its flexibility and modular implementation capability. However, WPM suffers from high peak-to-average power ratio (PAPR), which results in signal distortion when a high-power amplifier is employed at the transmitter. The partial transmit sequence (PTS) is an attractive PAPR reduction method, but its computational complexity is high. In this paper, we propose a PTS based on the genetic algorithm (GA) scheme (GA-PTS) to reduce the computational complexity of the PTS in the lifting-based WPM (LBWPM) systems. Simulation results show that the proposed GA-PTS scheme provides significant …
A Comprehensive Comparison Of Features And Embedding Methods For Face Recognition, Hasan Serhan Yavuz, Hakan Çevi̇kalp, Ri̇fat Edi̇zkan
A Comprehensive Comparison Of Features And Embedding Methods For Face Recognition, Hasan Serhan Yavuz, Hakan Çevi̇kalp, Ri̇fat Edi̇zkan
Turkish Journal of Electrical Engineering and Computer Sciences
Face recognition is an essential issue in modern-day applications since it can be used in many areas for several purposes. Many methods have been proposed for face recognition. It is a difficult task since variations in lighting, instantaneous mimic varieties, posing angles, and scaling differences can drastically change the appearance of the face. To suppress these complications, effective feature extraction and proper alignment of face images gain as much importance as the recognition method choice. In this paper, we provide an extensive comparison of the state-of-the-art face recognition methods with the most well-known techniques used in feature representation. In order …
Improving The Srf Method To Compensate Low-Order Harmonics Under Nonsinusoidal Network Voltages, Javad Modarresi, Mehdi Fallah, Eskandar Ghokipour, Mohammad Tavakoli Bina
Improving The Srf Method To Compensate Low-Order Harmonics Under Nonsinusoidal Network Voltages, Javad Modarresi, Mehdi Fallah, Eskandar Ghokipour, Mohammad Tavakoli Bina
Turkish Journal of Electrical Engineering and Computer Sciences
Increasing the application of power in electronic devices has increased the harmonics in power systems. Numerous methods like the synchronous reference frame (SRF) and the p-q-based method have been suggested to overcome the effects of these harmonics. The conventional SRF method provides acceptable results in harmonic compensation of high-order harmonics (higher than the fourth order), but the transient response time will be drastically increased in the presence of low-order harmonics due to the existence of a conventional low-pass filter. Furthermore, if the load terminal voltages are distorted, then the conventional SRF method will become unable to implement load current compensation. …
Empirical Mode Decomposition Application For Short-Term Flicker Severity, Yasemi̇n Önal, Ömer Nezi̇h Gerek, Doğan Gökhan Ece
Empirical Mode Decomposition Application For Short-Term Flicker Severity, Yasemi̇n Önal, Ömer Nezi̇h Gerek, Doğan Gökhan Ece
Turkish Journal of Electrical Engineering and Computer Sciences
In this article, an approach based on empirical mode decomposition (EMD) is suggested in order to calculate short-term flicker severity, Pst, in power systems. EMD is a new signal processing method used for the analysis of nonlinear and nonstationary signals. Pst is an important quantity in the electric power quality index defined by the International Electrotechnical Commission. In the suggested approach, the voltage signal is separated into intrinsic mode function components using EMD. These components are used for calculating the voltage flicker amplitude and frequency, and Pst is calculated as a result of the statistical evaluation of flicker amplitude. EMD …
Upper Limb Rehabilitation Robot For Physical Therapy: Design, Control, And Testing, Erhan Akdoğan
Upper Limb Rehabilitation Robot For Physical Therapy: Design, Control, And Testing, Erhan Akdoğan
Turkish Journal of Electrical Engineering and Computer Sciences
In recent years, the treatment process of patients and disabled people who need rehabilitation and physical medicine has become more effective with the use of new devices and developing technology. The rehabilitation robot is one of the most important developments in new technology. The right therapeutic exercises and the objectivity of the evaluation of the range of motion (ROM; generated torque and muscular activation measurement of the patient) are extremely important factors during treatment. In this study, a lower limb rehabilitation robot was modified and controlled for upper limbs. The retrofitted robot system is able to do passive, active, and …
Square Root Central Difference-Based Fastslam Approach Improved By Differential Evolution, Haydar Ankişhan, Fi̇kret Ari, Emre Öner Tartan, Ahmet Güngör Pakfi̇li̇z
Square Root Central Difference-Based Fastslam Approach Improved By Differential Evolution, Haydar Ankişhan, Fi̇kret Ari, Emre Öner Tartan, Ahmet Güngör Pakfi̇li̇z
Turkish Journal of Electrical Engineering and Computer Sciences
This study presents a new approach to improve the performance of FastSLAM. The aim of the study is to obtain a more robust algorithm for FastSLAM applications by using a Kalman filter that uses Stirling's polynomial interpolation formula. In this paper, some new improvements have been proposed; the first approach is the square root central difference Kalman filter-based FastSLAM, called SRCD-FastSLAM. In this method, autonomous vehicle (or robot) position, landmarks' position estimations, and importance weight calculations of the particle filter are provided by the SRCD-Kalman filter. The second approach is an improved version of the SRCD-FastSLAM in which particles are …
An Analytical Formulation With Ill-Conditioned Numerical Scheme And Its Remedy: Scattering By Two Circular Impedance Cylinders, Emrah Sever, Fati̇h Di̇kmen, Olga Alexandrovna Suvorova, Yury Alexanderovich Tuchkin
An Analytical Formulation With Ill-Conditioned Numerical Scheme And Its Remedy: Scattering By Two Circular Impedance Cylinders, Emrah Sever, Fati̇h Di̇kmen, Olga Alexandrovna Suvorova, Yury Alexanderovich Tuchkin
Turkish Journal of Electrical Engineering and Computer Sciences
The regularization of the well-known analytical formulation of the monochromatic electromagnetic wave scattering problem from a syvstem with two neighbor impedance circular cylinders is presented. It is the improvement and extension of the work done for scattering from two perfectly conducting circular cylinders. Numerical results show that it is numerically much safer to solve the obtained infinite algebraic system at a lower truncation number also by ensuring the reliability of the solution.
On Scalable Rdfs Reasoning Using A Hybrid Approach, Tuğba Külahcioğlu, Hasan Bulut
On Scalable Rdfs Reasoning Using A Hybrid Approach, Tuğba Külahcioğlu, Hasan Bulut
Turkish Journal of Electrical Engineering and Computer Sciences
Reasoning is a vital ability for semantic web applications since they aim to understand and interpret the data on the World Wide Web. However, reasoning of large data sets is one of the challenges facing semantic web applications. In this paper, we present new approaches for scalable Resource Description Framework Schema (RDFS) reasoning. Our RDFS specific term-based partitioning algorithm determines required schema elements for each data partition while eliminating the data partitions that will not produce any inferences. With the two-level partitioning approach, we are able to carry out reasoning with limited resources. In our hybrid approach, we integrate two …
Ray Tracing Technique For Shaping A Dual Reflector Antenna System, Md Rezwanul Ahsan, Mohammad Tariqul Islam, Yoshihide Yamada, Norbahiah Misran
Ray Tracing Technique For Shaping A Dual Reflector Antenna System, Md Rezwanul Ahsan, Mohammad Tariqul Islam, Yoshihide Yamada, Norbahiah Misran
Turkish Journal of Electrical Engineering and Computer Sciences
In radio astronomy applications, antennas having the highest aperture efficiencies are requested. In order to meet this request, a reflector shaping program for dual reflector antennas has been developed. The design procedure is based on the geometrical optics where differential equations have been formulated to define the ray trace of the antenna system. Recently, the fourth generation programming language MATLAB has become well known for its numerical computing environment and very useful three-dimensional data visualization functions. The authors wished to make a dual reflector shaping program by a ray tracing method in MATLAB. In this paper, details of the program …
How To Categorize Emotional Speech Signals With Respect To The Speaker's Degree Of Emotional Intensity, Salman Karimi, Mohammad Hossein Sedaaghi
How To Categorize Emotional Speech Signals With Respect To The Speaker's Degree Of Emotional Intensity, Salman Karimi, Mohammad Hossein Sedaaghi
Turkish Journal of Electrical Engineering and Computer Sciences
Recently, classifying different emotional content of speech signals automatically has become one of the most important comprehensive inquiries. The main subject in this field is related to the improvement of the correct classification rate (CCR) resulting from the proposed techniques. However, a literature review shows that there is no notable research on finding appropriate parameters that are related to the intensity of emotions. In this article, we investigate the proper features to be employed in the recognition of emotional speech utterances according to their intensities. In this manner, 4 emotional classes of the Berlin Emotional Speech database, happiness, anger, fear, …
Reconstructive Sensing Circuit For Complementary Resistive Switches-Based Crossbar Memories, Ertuğrul Karakulak, Reşat Mutlu, Erdem Uçar
Reconstructive Sensing Circuit For Complementary Resistive Switches-Based Crossbar Memories, Ertuğrul Karakulak, Reşat Mutlu, Erdem Uçar
Turkish Journal of Electrical Engineering and Computer Sciences
Complementary resistive switches (CRSs) are suggested as an alternative to one-cell memristor memories to decrease leakage currents. However, their sensing is more difficult and complex than one-cell memristor memories. A method has been given for sensing their state using only DC voltages in the literature. However, in this strategy, sensing one of the logic states results in the destruction of the state and the destroyed state must be written again. To the best of our knowledge, a circuit with this sensing strategy does not exist in the literature yet. In this paper, such a circuit employing this method, which is …