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Analysis And Optimization Of Mobile Phone Antenna Radiation Performance In The Presence Of Head And Hand Phantoms, Erdem Ofli, Chung-Huan Li, Nicolas Chavannes, Niels Kuster
Analysis And Optimization Of Mobile Phone Antenna Radiation Performance In The Presence Of Head And Hand Phantoms, Erdem Ofli, Chung-Huan Li, Nicolas Chavannes, Niels Kuster
Turkish Journal of Electrical Engineering and Computer Sciences
A commercial clam shell phone CAD model is used to numerically investigate the effect of a hand phantom on mobile phone antenna radiation performance. The simulation results show that the grip of the hand phantom is the most important parameter to antenna performance. The antenna is converted into a parameterized form, then optimized to achieve the targeted multi-band performance in real-usage conditions.
Dual-Band Split-Ring Antenna Design For Wlan Applications, S. Cumhur Başaran, Yunus E. Erdemli̇
Dual-Band Split-Ring Antenna Design For Wlan Applications, S. Cumhur Başaran, Yunus E. Erdemli̇
Turkish Journal of Electrical Engineering and Computer Sciences
A dual-band microstrip antenna based on split-ring elements is introduced for WLAN (2.4/5.2 GHz) applications. The proposed split-ring antenna (SRA) has a compact novel design which provides about 2% impedance-bandwidth without a need for additional matching network. Analysis and design of the proposed microstrip antenna is carried out by means of full-wave simulators based on the finite-element method.
Comparison Of Rectangular And Cylindrical Fdtd Representations On A Ring Resonator Problem, Funda Akleman, Levent Sevgi̇
Comparison Of Rectangular And Cylindrical Fdtd Representations On A Ring Resonator Problem, Funda Akleman, Levent Sevgi̇
Turkish Journal of Electrical Engineering and Computer Sciences
The aim of this paper is to discuss rectangular and cylindrical representations of finite-difference time-domain (FDTD) method over characteristic tests and comparisons. A ring resonator is chosen as a canonical structure and modeled with both rectangular- and cylindrical-FDTD packages. Calibration against analytical exact solution derived in terms of cylindrical Bessel functions is also performed. It is shown that rectangular-FDTD with periodic boundary condition, where the computation domain is reduced, can also be applied in modeling circular structures.
Cover And Contents
Turkish Journal of Electrical Engineering and Computer Sciences
No abstract provided.
Method Of Moments Solution By Using Sinc-Type Basis Functions For The Scattering From A Finite Number Of Conducting Strip Gratings, Taner Oğuzer, Fadil Kuyucuoğlu
Method Of Moments Solution By Using Sinc-Type Basis Functions For The Scattering From A Finite Number Of Conducting Strip Gratings, Taner Oğuzer, Fadil Kuyucuoğlu
Turkish Journal of Electrical Engineering and Computer Sciences
A numerical method of moments (MoM) solution is applied to the electromagnetic scattering from a periodic finite conducting strip array when the incident electromagnetic plane wave E and H polarizations illuminate the grating. For such grating strip geometry, we deal with singular integral equations arising from Neumann and Dirichlet boundary conditions. MoM is applied using band-limited sinc functions as basis and testing functions. The Galerkin approach is followed in MoM formulation. The properties of the sinc function, with the infinite integral, are exploited in the computations of the main matrix elements. Also, the error in our approach goes to zero …
Comparison Of Basic Linear Filters In Extracting Auditory Evoked Potentials, Serap Aydin
Comparison Of Basic Linear Filters In Extracting Auditory Evoked Potentials, Serap Aydin
Turkish Journal of Electrical Engineering and Computer Sciences
In the present study, the performances of two well-known linear filtering techniques are compared for extraction of auditory Evoked Potential (EP) from a relatively small number of sweeps. Both experimental and simulated data are filtered by the two algorithms into two groups. Group A consists of Wiener filtering (WF) applications, where conventional WF and Coherence Weighted WF (CWWF)) have been assessed in combination with the Subspace Method (SM). Group B consists of the well-known adaptive filtering algorithms Least Mean Square (LMS), Recursive Least Square (RLS), and one-step Kalman filtering (KF). Both groups are tested with respect to signal-to-noise ratio (SNR) …
Zero Crossing Counter For Accuracy Improvement Of Fmcw Range Detection, Si̇nan Kurt, Şi̇mşek Demi̇r, Altunkan Hizal
Zero Crossing Counter For Accuracy Improvement Of Fmcw Range Detection, Si̇nan Kurt, Şi̇mşek Demi̇r, Altunkan Hizal
Turkish Journal of Electrical Engineering and Computer Sciences
For civil and military purposes FMCW radars are widely used. The theoretical background is well-established. Nevertheless, improvement of various aspects of these radars is still required. Signal processing is one of the crucial points of the system which determines the capabilities of the radar. In this study a zero crossing detector implementation, which can be efficiently used for target detection and range calculation in short range FMCW range detector is proposed. The duration between consecutive zero-crossings are used as the data instead of the number of cycles per unit time. Experimental evaluation of its performance is also given.
Online Tuning Of Set-Point Regulator With A Blending Mechanism Using Pi Controller, Engi̇n Yeşi̇l, Müjde Güzelkaya, İbrahi̇m Eksi̇n, Ö. Aydin Teki̇n
Online Tuning Of Set-Point Regulator With A Blending Mechanism Using Pi Controller, Engi̇n Yeşi̇l, Müjde Güzelkaya, İbrahi̇m Eksi̇n, Ö. Aydin Teki̇n
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a new control structure that exploits the advantages of one degree of freedom (1-DOF) and two degree of freedom (2-DOF) control structures with an online tuned set-point regulator with blending mechanism (SPR-BM) is proposed. In this structure, the filtered output of the reference and the pure reference signals are blended so that the overall performance of the system is ameliorated with respect to load disturbance rejection and set-point following. Internal Model Control (IMC) based PI controller is used as the primary controller and the blending dynamics are determined with the aim of producing a system output that …
A New Approach Using Temporal Radial Basis Function In Chronological Series, Mustapha Guezouri
A New Approach Using Temporal Radial Basis Function In Chronological Series, Mustapha Guezouri
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we present an extended form of Radial Basis Function network called Temporal-RBF (T-RBF) network. This extended network can be used in decision rules and classification in Spatio-Temporal domain applications, like speech recognition, economic fluctuations, seismic measurements and robotics applications. We found that such a network complies with relative ease to constraints such as capacity of universal approximation, sensibility of node, local generalisation in receptive field, etc. For an optimal solution based on a probabilistic approach with a minimum of complexity, we propose two TRBF models (1 and 2). Application to the problem of Mackey-Glass time series has …
Cover And Contents
Turkish Journal of Electrical Engineering and Computer Sciences
No abstract provided.
Role Of Artificial Intelligence In The Reliability Evaluation Of Electric Power Systems, Chanan Singh, Lingfeng Wang
Role Of Artificial Intelligence In The Reliability Evaluation Of Electric Power Systems, Chanan Singh, Lingfeng Wang
Turkish Journal of Electrical Engineering and Computer Sciences
Every reliability analysis effort, in some way, involves searching the state space of the system for those states that represent the events of interest, typically failure of the system or a given node to meet the demand. This essentially translates into a search procedure to efficiently identify states to be examined and then using a mechanism to evaluate these states. Traditionally, reliability analysis methods are based either on an implicit or explicit enumeration process or Monte Carlo sampling. More recently, methods based on artificial intelligence have been investigated both as an alternative to Monte Carlo for the search process as …
Dispersion Analysis Of The Adi-Fdtd And S-Fdtd Methods, Mehmet Kuşaf, Abdullah Y. Öztoprak
Dispersion Analysis Of The Adi-Fdtd And S-Fdtd Methods, Mehmet Kuşaf, Abdullah Y. Öztoprak
Turkish Journal of Electrical Engineering and Computer Sciences
Numerical dispersion performances of ADI-FDTD and S-FDTD methods have been compared. It has been shown that for time steps below the stability limits of the S-FDTD method it has much better dispersion performance compared with the ADI-FDTD method and that the S-FDTD method can be usefully employed for space increments in the order of \lambda/25 to \lambda/50.
Power Distortion Issues In Wind Turbine Power Systems Under Transient States, Tadeusz Lobos, Jacek Rezmer, Tomasz Sikorski, Zbigniew Waclawek
Power Distortion Issues In Wind Turbine Power Systems Under Transient States, Tadeusz Lobos, Jacek Rezmer, Tomasz Sikorski, Zbigniew Waclawek
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper time-frequency methods have been investigated for complex investigations of transient states in wind power plants. Application of parallel processing in time and frequency domain brought new findings in description of wind power plants working under transient conditions. Proposed algorithms represents standard Short-Time Fourier Transform (STFT) as well as alternative methods associated with Cohen's class: Choi-Williams Distribution (CWD) and Zhao-Atlas-Marks Distribution (ZAMD). In order to explore advantages and disadvantages of the method several experiments were performed using model of squirrel-cage induction machine connected directly to the grid. Investigated phenomena concerned power distortion caused by switching-on capacitor banks and …
Synthesis And Properties Of New Polyamides Based On 4-Phenylenediacrylic Acid And Hydantoin Derivatives In The Main Chain, Khalil Faghihi
Synthesis And Properties Of New Polyamides Based On 4-Phenylenediacrylic Acid And Hydantoin Derivatives In The Main Chain, Khalil Faghihi
Turkish Journal of Chemistry
Six new polyamides (5a-f) containing p-phenylenediacrylic and hydantoin moieties in the main chain were prepared by direct polycondensation reaction of 4-phenylenediacrylic acid (3) with 6 different hydantoin derivatives (4a-f) using thionyl chloride and pyridine as condensing agents and N-methyl-2-pyrolidone as solvent. These new polymers (5a-f) were obtained in high yield and inherent viscosity between 0.35-0.55 dL/g. The resulting polyamides were characterized by elemental analysis, viscosity measurements, thermal gravimetric analysis (TGA and DTG), solubility test, and FT-IR and UV-vis spectroscopy. 4-Phenylenediacrylic acid (3) was prepared by the reaction of terephthal aldehyde (1) with malonic acid (2) in the presence of pyridine.
One-Step Synthesis Of Hyaluronic Acid-Based (Sub)Micron Hydrogel Particles: Process Optimization And Preliminary Characterization, Nurettin Sahiner, Xinqiao Jia
One-Step Synthesis Of Hyaluronic Acid-Based (Sub)Micron Hydrogel Particles: Process Optimization And Preliminary Characterization, Nurettin Sahiner, Xinqiao Jia
Turkish Journal of Chemistry
Hyaluronic acid (HA)-based (sub)micron hydrogel particles were synthesized by crosslinking virgin HA with divinyl sulfone (DVS) in sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micelle systems under basic conditions. Experimental parameters including HA molecular weight, solution concentration, and reaction time were systematically varied in order to obtain well defined hydrogel particles. The use of a cosurfactant, 1-heptanol (1-HP), had a profound effect on the reaction kinetics and the particle morphology. The resulting particles exhibit negative charges on their surfaces. In vitro biocompatibility study indicates that these particles do not cause severe death to the cultured fibroblasts. These HA-based hydrogel particles are promising candidates …
Electrocatalytic Oxidation Of D-Glucose Using A Cd Ad-Atom-Modified Au(111) Electrode In Alkaline Solution, Zekerya Dursun, Sami Ben Aoun, Isao Taniguchi
Electrocatalytic Oxidation Of D-Glucose Using A Cd Ad-Atom-Modified Au(111) Electrode In Alkaline Solution, Zekerya Dursun, Sami Ben Aoun, Isao Taniguchi
Turkish Journal of Chemistry
Au(111) single crystal electrodes were modified by underpotential deposition (UPD) of Cd ad-atoms with different coverages, which were used for the electrocatalytic oxidation of glucose in alkaline media. The catalytic activity of the electrodes was dependent on how the Cd ad-atoms covered the surface. Under the presented experimental conditions the monolayer (ML) Cd ad-atom-covered Au(111) electrode had the best catalytic activity on D-glucose oxidation, in terms of both potential shifts and peak current increases, as compared to the 0.11, 0.5, and 2 ML covered and bare Au(111) electrodes. Double layer capacity measurements revealed that the shifts of the potential of …
Solid Phase Extraction Of Cadmium In Edible Oils Using Zinc Piperazinedithiocarbamate And Its Determination By Flame Atomic Absorption Spectrometry, Mehtap Yağan Aşci, Ayşegül Efendi̇oğlu, Beki̇r Bati
Solid Phase Extraction Of Cadmium In Edible Oils Using Zinc Piperazinedithiocarbamate And Its Determination By Flame Atomic Absorption Spectrometry, Mehtap Yağan Aşci, Ayşegül Efendi̇oğlu, Beki̇r Bati
Turkish Journal of Chemistry
A method was developed for preconcentration of cadmium with zinc-piperazinedithiocarbamate (ZnPDC) in edible oils and its determination by flame atomic absorption spectrometer (FAAS). The preconcentration method is based on the adsorption of the Cd(II) on to ZnPDC and the elution of them with mercury(II) nitrate. The accuracy of the method was tested with standard reference material (CONOSTAN S-21) and Cd added samples. Under optimum conditions, the recovery and the detection limit for cadmium were 99.67% (\pm 0.67) and 0.028 mg/L, respectively. The calibration curve was linear over the concentration range 0.1-3.0 mg/L (r^2 = 0.9979). The proposed method was applied …
Interaction Of Mefenamic Acid With Cobalt(Ii) Ions In Aqueous Media: Evaluation Via Classic And Response Surface Methods, Mohammad Edrissi, Nima Razzaghi Asl, Behrooz Madjidi
Interaction Of Mefenamic Acid With Cobalt(Ii) Ions In Aqueous Media: Evaluation Via Classic And Response Surface Methods, Mohammad Edrissi, Nima Razzaghi Asl, Behrooz Madjidi
Turkish Journal of Chemistry
Mefenamic acid reacts with cobalt(II) ions in aqueous alkaline medium to form a highly stable deep brown complex at ambient temperature. The complexation process was optimized in terms of pH, temperature, agitation rate, and contact time using classical studies. A response surface method based on Box-Behnken design was used to statistically model the complexation reaction and investigate factor effects along with their interactions. A quadratic model was developed using experimental data with a correlation coefficient of 0.9609. Numerical optimization was performed to achieve the optimum solutions of factor combinations. The results of the classical investigation and statistical method were in …
Langmuir Aggregation Of Congo Red On Cpc And Its Application, Xiang-Hu Liu, Jiao-Rong Ren, Ya-Nan Huang, Jing Bai, Hong-Wen Gao
Langmuir Aggregation Of Congo Red On Cpc And Its Application, Xiang-Hu Liu, Jiao-Rong Ren, Ya-Nan Huang, Jing Bai, Hong-Wen Gao
Turkish Journal of Chemistry
In this paper, microsurface adsorption-spectral correction technique (MASCT) was used to research the interaction between negatively charged sodium diphenyl diazo-bis-\alpha -naphthylamine-4-sulfonate (Congo Red, CR) and positively charged cetylpyridinium chloride (CPC) in a pH 2.03 BR buffer solution. The experiment results indicate that CR was absorbed on the surface of CPC mainly through electrostatic attraction. This aggregation obeys the Langmuir isothermal adsorption equation. The maximal binding number of CR to CPC was calculated to be 1.2 and the adsorption constant was about 2.03 \times 10^5 L/mol. This CR-CPC binding product is insensitive to a concentrated electrolyte solution, but higher temperature influences …
Co Oxidation Over Mono And Bi-Metallic Sequentially Impregnated Pd-Pt Catalysts, Sarp Kaya, Deni̇z Üner
Co Oxidation Over Mono And Bi-Metallic Sequentially Impregnated Pd-Pt Catalysts, Sarp Kaya, Deni̇z Üner
Turkish Journal of Chemistry
The CO oxidation capability of sequentially impregnated Pd-Pt/\gamma -Al_2O_3 bimetallic catalysts was tested. The CO oxidation light-off curves were hierarchically spaced between monometallic Pd and monometallic Pt, which showed the highest and lowest activity, respectively, indicating that sequential impregnation did not result in the formation of bimetallic particles, but that the catalysts remained as monometallic entities over the support surface. An investigation of the effect of CO partial pressure on the reaction rates over monometallic catalysts indicated that in the presence of excess CO the surface of Pt was poisoned. On the other hand, in the presence of excess CO …
Hydrogenation Of Citral Over Pt And Pt-Sn Catalysts, Hi̇lal Aykaç, Selahatti̇n Yilmaz
Hydrogenation Of Citral Over Pt And Pt-Sn Catalysts, Hi̇lal Aykaç, Selahatti̇n Yilmaz
Turkish Journal of Chemistry
Hydrogenation of citral on monometallic (Pt) and bimetallic (Pt-Sn) catalysts was investigated. It was found that the catalyst activities and product distributions were different over Na-Y and Clino supports. Among monometallic catalysts, Pt/Na-Y was more selective to citronellol (3.9%) and unsaturated alcohols, geraniol and nerol, (14.1%). Sn addition increased the catalyst activities. However, its effect on product distribution differed. Yield of geraniol+nerol changed from 5.1% to 19.7% over Clino. However, selectivity to unsaturated alcohols over Na-Y decreased when it was prepared as a bimetallic catalyst support. Unsaturated alcohol formation was favored when there was a metal support interaction over monometallic …
New Flame-Retardant Poly(Ester-Imide)S Containing Phosphine Oxide Moieties In The Main Chain: Synthesis And Properties, Khalil Faghihi
New Flame-Retardant Poly(Ester-Imide)S Containing Phosphine Oxide Moieties In The Main Chain: Synthesis And Properties, Khalil Faghihi
Turkish Journal of Chemistry
Six new flame-retardant poly(ester-imide)s (9a-f) with high inherent viscosity and containing phosphine oxide moieties in the main chain were synthesized from the polycondensation reaction of N,N-(3,3-diphenylphenyl phosphine oxide) bistrimellitimide diacid chloride (7) with 6 aromatic diols (8a-f) by 2 different methods:--solution and microwave-assisted polycondensation. The results showed that compared to solution polycondensation, the microwave-assisted polycondensation reaction using a domestic microwave oven proceeded rapidly and was completed within about 9-12 min. All of the obtained polymers were fully characterized by means of elemental analysis, viscosity measurement, solubility testing, and FT-IR spectroscopy. Thermal properties and flame retardant behavior of the PEIs (9a-f) …
Synthesis And Properties Of Novel Photosensitive Poly(Amide-Imide)S Containing Chalcone Moiety And Aromatic Diamines In The Main Chain, Khalil Faghihi, Zohreh Mozafari
Synthesis And Properties Of Novel Photosensitive Poly(Amide-Imide)S Containing Chalcone Moiety And Aromatic Diamines In The Main Chain, Khalil Faghihi, Zohreh Mozafari
Turkish Journal of Chemistry
Six new poly(amide-imide)s were synthesized by the polycondensation reaction of 1,3-bis[4,4'-bis(trimellityimido) phenyl]-2-propenone (6) with 3,3'-diamino diphenyl sulfone (7a), 4,4'-diamino diphenyl sulfone (7b), 4,4'-diamino diphenyl ether (7c), 1,5-diamino naphthalene (7d), 6-phenyl-1,3,5-triazine (7e), and 6-choloro-1,3-diazine (7f) in a medium consisting of N-methyl-2- pyrrolidone, triphenyl phosphite, calcium chloride, and pyridine. The polycondensation reaction produced a series of novel poly(amide-imide)s (8a-f) in high yield and with inherent viscosities between 0.42 and 0.62 dL/g. The resulting polymers were characterized by elemental analysis, viscosity measurement, solubility testing, thermo-gravimetric analysis (TGA & DTG), FT-IR, and UV-VIS spectroscopy.
Production Of (S)-(-)-1-(1´-Napthyl) Ethanol By Rhodotorula Glutinis Isolate Using Ram Horn Peptone, Esabi̇ Başaran Kurbanoğlu, Kani̇ Zi̇lbeyaz, Namudar I. Kurbanoğlu, Mesut Taşkin, Hamdullah Kiliç
Production Of (S)-(-)-1-(1´-Napthyl) Ethanol By Rhodotorula Glutinis Isolate Using Ram Horn Peptone, Esabi̇ Başaran Kurbanoğlu, Kani̇ Zi̇lbeyaz, Namudar I. Kurbanoğlu, Mesut Taşkin, Hamdullah Kiliç
Turkish Journal of Chemistry
The bioreduction of 1-acetonaphthone 1 by locally isolated Rhodotorula glutinis strains using ram horn peptone (RHP) gave (S)-(-)-1-(1´-naphthyl) ethanol (2), an important pharmaceutical intermediate. R. glutinis strains were isolated from the water of fermented Salix leaves. Optimum fermentation conditions for the production of 2 were 200 rpm, 32 °C, and pH 6.5. The production of 2 with excellent enantiomeric excess (>99%), and good conversion (100%) and yield (78%) under optimum conditions was achieved up to preparative scale via a fermenter. Wide temperature, pH, time, and agitation ranges did not affect the enantiomeric excess (ee) of the bioreduction product. A …
Preparation Of Palladium Composite Membranes On Pore Structure Modified And Non-Modified Supports By Electroless Plating Procedure, Sali̇ha Kiliçarslan, Osman Muzaffer Afyon, Meltem Doğan
Preparation Of Palladium Composite Membranes On Pore Structure Modified And Non-Modified Supports By Electroless Plating Procedure, Sali̇ha Kiliçarslan, Osman Muzaffer Afyon, Meltem Doğan
Turkish Journal of Chemistry
The effects of pore structure of the support on the plating morphology, thickness, and composition were investigated in an electroless plating procedure. Some of the plating studies were carried out directly on commercially available porous glass supports, while others were performed on modified supports. Two modification steps with alumina were applied on tubular supports. Formation of a 60-\mu m-thick layer on the modified support was detected by SEM analysis after the first 2 plating steps, while layer formation was not observed on the non-modified support. It was shown that the formation of a new layer started on the modified support, …