Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- Turkey (105)
- 1 (99)
- 2 (82)
- Classification (70)
- Optimization (65)
-
- Deep learning (61)
- Genetic algorithm (61)
- Machine learning (61)
- Synthesis (61)
- Adsorption (53)
- Particle swarm optimization (51)
- Antimicrobial activity (47)
- Geochemistry (47)
- 3 (44)
- Stability (39)
- Artificial neural network (37)
- Phthalocyanine (35)
- Support vector machine (34)
- Feature extraction (32)
- Wireless sensor networks (31)
- Antibacterial activity (29)
- Artificial neural networks (28)
- Feature selection (28)
- Copper (27)
- Cytotoxicity (27)
- Power quality (27)
- Fuzzy logic (26)
- Molecular docking (26)
- Palladium (26)
- Preconcentration (26)
- Publication Year
Articles 7081 - 7110 of 10319
Full-Text Articles in Physical Sciences and Mathematics
Performance Evaluation Of Nonparametric Ica Algorithm For Fetal Ecg Extraction, Yusuf Sevi̇m, Ayten Atasoy
Performance Evaluation Of Nonparametric Ica Algorithm For Fetal Ecg Extraction, Yusuf Sevi̇m, Ayten Atasoy
Turkish Journal of Electrical Engineering and Computer Sciences
Fetal electrocardiograms (FECG) contain important indications about the health and condition of the fetus. In this respect, it is crucial to apply a robust algorithm to ECG data for extraction of the FECG signal. Most of the independent component analysis (ICA) algorithms used for this purpose rely on simple statistical models. Such algorithms can fail to separate desired signals when the assumed statistical model is inaccurate. Statistical models can be estimated accurately using kernel density estimation methods. Therefore, the kernel density estimation method was used in this paper for building an ICA algorithm (nonparametric ICA: NpICA) and the algorithm was …
Learning Control Of Robot Manipulators In The Presence Of Additive Disturbances, Enver Tatlicioğlu
Learning Control Of Robot Manipulators In The Presence Of Additive Disturbances, Enver Tatlicioğlu
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a learning controller for robot manipulators is developed. The controller is proven to yield in a semi-global asymptotic result in the presence of additive input and output disturbances. Lyapunov-based techniques are used to guarantee that the tracking error is asymptotically driven to zero. Numerical simulation results are presented to demonstrate the viability of the proposed learning controller.
A Multi-Lateral Rehabilitation System, Aykut Ci̇han Satici, Ahmetcan Erdoğan, Volkan Patoğlu
A Multi-Lateral Rehabilitation System, Aykut Ci̇han Satici, Ahmetcan Erdoğan, Volkan Patoğlu
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes a multi-lateral shared control concept for robot assisted rehabilitation. In particular, a dual-user force-feedback teleoperation control architecture is implemented on a forearm-wrist rehabilitation system consisting of two kinematically dissimilar robotic devices. The multi-lateral rehabilitation system allows for patients to train with on-line virtual dynamic tasks in collaboration with a therapist. Different control authority can be assigned to each agent so that therapists can guide or evaluate movements of patients, or share the control with them. The collaboration is implemented using a dual-user force-feedback teleoperation control architecture, in which a dominance factor determines the authority of each agent …
Delay-Dependent Stability Criteria For Interval Time-Varying Delay Systems With Nonuniform Delay Partitioning Approach, Mehmet Nur Alpaslan Parlakçi
Delay-Dependent Stability Criteria For Interval Time-Varying Delay Systems With Nonuniform Delay Partitioning Approach, Mehmet Nur Alpaslan Parlakçi
Turkish Journal of Electrical Engineering and Computer Sciences
This paper investigates the conservatism reduction of Lyapunov-Krasovskii based conditions for the stability of a class of interval time-varying delay systems. The main idea is based on the nonuniform decomposition of the integral terms of the Lyapunov-Krasovskii functional. The delay interval is decomposed into a finite number of nonuniform segments with some scaling parameters. Both differentiable delay case and nondifferentiable delay case and unknown delay derivative bound case are taken into consideration. Sufficient delay-dependent stability criteria are derived in terms of matrix inequalities. Two suboptimal delay fractionation schemes, namely, linearization with cone complementary technique and linearization under additional constraints are …
Spoiler Effects Reduction With Using Active Power Filter On A Direct Torque Controlled Induction Machine, İbrahi̇m Alişkan, Kayhan Gülez, Yusuf Altun
Spoiler Effects Reduction With Using Active Power Filter On A Direct Torque Controlled Induction Machine, İbrahi̇m Alişkan, Kayhan Gülez, Yusuf Altun
Turkish Journal of Electrical Engineering and Computer Sciences
Harmonics, which may be placed in electrical systems, have important effects on performance parameters of electrical motors. In this paper, effects of electrical power system voltage harmonics on torque position of induction motors are dealt with. System modeling with Pulse Width Modulation (PWM) type Active Power Filter (APF) is used for reducing these effects. APF, as a subsystem, is placed into torque control system entrance to save the control system and induction motor output torque. Motor outputs, that are before-after APF connections, are handed for understanding effects of voltage harmonics. Since APF design was based on voltage harmonics, Electromagnetic Interference …
Active Vibration Control Of Seismic Excited Structural System Using Lmi-Based Mixed H_2/H_{\Infty} State Feedback Controller, Hakan Yazici, Rahmi̇ Güçlü
Active Vibration Control Of Seismic Excited Structural System Using Lmi-Based Mixed H_2/H_{\Infty} State Feedback Controller, Hakan Yazici, Rahmi̇ Güçlü
Turkish Journal of Electrical Engineering and Computer Sciences
This paper is concerned with the active vibration control of a four-degree-of-freedom structure, which is effected by earthquake. To obtain desired time history and frequency responses for solution of active vibration control problem, Linear Matrix Inequality (LMI) based state-feedback mixed H_2/H_{\infty} controller is designed in this study. The time history of ground motion of the Kobe earthquake in 1995, which is a disturbance input, is applied to modeled structure. At the end of the study, the time history of the storey displacements, velocities and frequency responses of both controlled and uncontrolled cases are presented and results are discussed. Performance of …
Induction Motor, State Estimation, Extended Kalman Filtering, Recurrent Neural Networks, Saadetti̇n Aksoy, Aydin Mühürcü
Induction Motor, State Estimation, Extended Kalman Filtering, Recurrent Neural Networks, Saadetti̇n Aksoy, Aydin Mühürcü
Turkish Journal of Electrical Engineering and Computer Sciences
This study presents a recurrent neural network (RNN)-based nonlinear state estimator that uses an Elman neural network structure (ENN) for state estimation of a squirrel-cage induction motor. The proposed algorithm only uses the measurements of the stator currents and the rotor angular speed, and it learns the dynamic behavior of the state observer from these measurements through prediction error minimization. A squirrel-cage induction motor was fed from sinusoidal, 6-step, and pulse-width modulation (PWM) supply sources at different times in order to observe the performance of the proposed estimator for different operation conditions. Estimation results showed that the proposed algorithm is …
Design And Development Of Workstation For Microparts Manipulation And Assembly, Emrah Deni̇z Kunt, Ahmet Teoman Naskali̇, İslam Shoukry Mohammed Khalil, Asif Sabanovic, Ebubeki̇r Yüksel
Design And Development Of Workstation For Microparts Manipulation And Assembly, Emrah Deni̇z Kunt, Ahmet Teoman Naskali̇, İslam Shoukry Mohammed Khalil, Asif Sabanovic, Ebubeki̇r Yüksel
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, microassembly system design issues are discussed with requirements, constraints and necessities for the development of an assembly platform, and these issues are shown over a versatile and reconfigurable microassembly workstation which is designed and realized as a research tool for investigation of the problems in microassembly and micromanipulation tasks. First prototype of a workstation and the development of a second prototype with enhancements on mechanical and control structure of the system are presented with details on the configuration of the systems. In addition, several experiments using a workstation are presented both on the first and the second …
Four Quadrant Fgmos Analog Multiplier, Si̇nem Keleş, Hulusi̇ Hakan Kuntman
Four Quadrant Fgmos Analog Multiplier, Si̇nem Keleş, Hulusi̇ Hakan Kuntman
Turkish Journal of Electrical Engineering and Computer Sciences
A novel four-quadrant analog multiplier using floating gate MOS (FGMOS) transistors operating in the saturation region is presented. The drain current is proportional to the square of the weighted sum of the input signals. This square law characteristic of the FGMOS transistor is used to implement the quarter square identity by utilizing only six FGMOS transistors. The main features of this remarkably simple multiplier circuit configuration are the large input signal range equal to 100% of the supply voltage, nonlinearity of 0.0081%, bandwidth of 1.4--1.5 Ghz and THD of maximum 2.67% (while the inputs are at their maximum values).
Applying The Finite Element Method To Analyze Predischarge Lightning Rods, Chin-Tsung Hsieh, Meng-Hui Wang, Cho-Yu Pan
Applying The Finite Element Method To Analyze Predischarge Lightning Rods, Chin-Tsung Hsieh, Meng-Hui Wang, Cho-Yu Pan
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, the finite element method is applied for analyzing 4 types of lightning rods in order to select the optimal lightning rod configuration. First, software is used to calculate the 2D protective coverage of different lighting rods, and 4 kinds of typical lightning rods are simulated in different conditions. The analyzed results are then applied for the selection of the optimal lighting rod and the frame of the lighting rod. The analyzed results would be useful for electrical engineers to design lightning rods that offer the most effective lighting protection; the simulated results are also useful for the …
Fully Parallel Ann-Based Arrhythmia Classifier On A Single-Chip Fpga: Fpaac, Ahmet Turan Özdemi̇r, Kenan Danişman
Fully Parallel Ann-Based Arrhythmia Classifier On A Single-Chip Fpga: Fpaac, Ahmet Turan Özdemi̇r, Kenan Danişman
Turkish Journal of Electrical Engineering and Computer Sciences
Recognition of cardiac arrhythmias by electrocardiogram (ECG) is an important issue for diagnosis of cardiac abnormalities. Many studies on recognition of cardiac arrhythmias by ECG, using various techniques, have been performed in the past 20 years. Artificial neural networks (ANNs) are the most widely used tool in medical diagnosis systems (MDS) because of their powerful prediction characteristics. An ANN model is inspired by real biological neural networks, with a parallel structure that is potentially fast for computation. However, the suggested ANN architectures in the literature can only be run sequentially, on powerful processors, due to their complexity. Our approach enables …
Design And Development Of A Tilt-Wing Uav, Ertuğrul Çeti̇nsoy, Efe Sirimoğlu, Kaan Taha Öner, Cevdet Hançer, Mustafa Ünel, Mahmut Faruk Akşi̇t, İlyas Kandemi̇r, Kayhan Gülez
Design And Development Of A Tilt-Wing Uav, Ertuğrul Çeti̇nsoy, Efe Sirimoğlu, Kaan Taha Öner, Cevdet Hançer, Mustafa Ünel, Mahmut Faruk Akşi̇t, İlyas Kandemi̇r, Kayhan Gülez
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, the mechanical and aerodynamic design, carbon composite production, hierarchical control system design and vertical flight tests of a new unmanned aerial vehicle (UAV), which is capable of VTOL (vertical takeoff and landing) like a helicopter and long range horizontal flight like an airplane, are presented. Real flight tests show that the aerial vehicle can successfully operate in VTOL mode. Kalman filtering is employed to obtain accurate roll and pitch angle estimations.
Ellipsoid Based L_2 Controller Design For Lpv Systems With Saturating Actuators, İbrahi̇m Beklan Küçükdemi̇ral, Levent Ucun, Yavuz Eren, Haluk Görgün, Gali̇p Cansever
Ellipsoid Based L_2 Controller Design For Lpv Systems With Saturating Actuators, İbrahi̇m Beklan Küçükdemi̇ral, Levent Ucun, Yavuz Eren, Haluk Görgün, Gali̇p Cansever
Turkish Journal of Electrical Engineering and Computer Sciences
This paper addresses the L_2 gain control problem for disturbance attenuation in Linear Parameter Varying (LPV) Systems having saturating actuators when the system is subjected to L_2 disturbances. In the presented method, saturating actuator is expressed analytically with a convex hull of some linear feedback which let us construct L_2 control problem via Linear Matrix Inequalities (LMIs) which are obtained by some ellipsoids. It is shown that the stability and disturbance rejection capabilities of the control system are all measured by means of these nested ellipsoids where the inner ellipsoid covers the initial conditions for states whereas the outer ellipsoid …
Enantioselective Complexation Of Chiral Lariat Crown Ethers And Chiral Primary Alkylammonium Perchlorates, Mehmet Zafer Köylü, Tarik Aral, Mehmet Karakaplan, Şafak Özhan Kocakaya, Hali̇l Hoşgören
Enantioselective Complexation Of Chiral Lariat Crown Ethers And Chiral Primary Alkylammonium Perchlorates, Mehmet Zafer Köylü, Tarik Aral, Mehmet Karakaplan, Şafak Özhan Kocakaya, Hali̇l Hoşgören
Turkish Journal of Chemistry
In order to investigate the enantiomeric recognition abilities toward 2 chiral alkylammonium perchlorates (AmI, AmII) by ^1H-NMR titration method in CDCl_3, 4 chiral lariat ethers 8-11 with a (p-methoxyphenoxy) methyl flexible side arm were used. The most effective enantiomeric recognition was obtained by LCEs 9 and 11 toward AmII, by K_R/K_S 6.58 and K_S/K_R 6.63, respectively. The effect of macroring size, subunit of macroring, and side arm appeared to have strong influence on the binding ability of these alkylammonium ions.
Polarographic Determination Of Anticancer Drug Vitamin K_3 With Direct And Indirect Methods/Application To Serum And K_3 Injection Solution, Ümmi̇han Taşkoparan Yilmaz, Güler Somer
Polarographic Determination Of Anticancer Drug Vitamin K_3 With Direct And Indirect Methods/Application To Serum And K_3 Injection Solution, Ümmi̇han Taşkoparan Yilmaz, Güler Somer
Turkish Journal of Chemistry
In this work, direct and indirect methods for determination of vitamin K_3 were developed using differential pulse polarography. The reaction between sulfite and the quinone (Q) form of vitamin K_3 was used for indirect determination, since the sulfite peak at -0.7 V is sharp and very reproducible in 0.1 M HAc NaAc (pH = 5.5). It was found that at pH 4.5-5.5, this reaction was quantitative and very fast when the temperature was 45 °C. For its direct determination, on the other hand, vitamin K_3 was standardized by the indirect method using standard sulfite as the reducing agent. The calibration …
Synthesis And Spectral Characterization Of A Decavanadate/Chitosan Complex, Violeta Dimitrova Kassabova Zhetcheva, Lilyana Parvanova Pavlova
Synthesis And Spectral Characterization Of A Decavanadate/Chitosan Complex, Violeta Dimitrova Kassabova Zhetcheva, Lilyana Parvanova Pavlova
Turkish Journal of Chemistry
A decavanadate/chitosan complex was synthesized by crosslinking chitosan with decavanadate anions at a pH of 3. The materials were characterized by Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), absorption spectroscopy (UV-Vis), and transmission electron microscopy (TEM). The spectroscopic results indicated that the decavanadate/chitosan complex was successfully obtained as result of an ionic crosslinking of the chitosan with decavanadate anions.
Stability Study Of Passive Film On Copper Surface As A Function Of Anodic Potential, Amtul Naseer, Athar Yaseen Khan
Stability Study Of Passive Film On Copper Surface As A Function Of Anodic Potential, Amtul Naseer, Athar Yaseen Khan
Turkish Journal of Chemistry
Results for passive film formation and breakdown on copper disk electrodes in buffer solutions, pH 9.2 and 8.5, were reported earlier. The present studies were carried out in a buffer solution, pH 8.0, and together these studies make good material for understanding the effect of pH changes on film texture as a function of potential. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to examine passive film and the variations it went through upon being treated potentiostatically in the range of -0.3 to 0.9 V. On the basis of equivalent circuits used for modeling impedance data in this …
Synthesis And Characterization Of Novel Benzovesamicol Analogs, Thaer Assaad
Synthesis And Characterization Of Novel Benzovesamicol Analogs, Thaer Assaad
Turkish Journal of Chemistry
Three new racemic vesamicol analogs were successfully prepared in good yields and high purity. All compounds were characterized by both IR and NMR spectroscopy. Compounds (\pm)-5 and (\pm)-6 showed a moderate lipophilicity compared with reference compounds IBVM and DRC140, respectively. However, the lipophilicity of DRC140 and (\pm)-9 showed very similar behaviors.
Controlled Growth Of Two-Dimensional Copper Nanoplates In Graphite Gallery, Xiaobei Bin, Jiazang Chen, Hong Cao
Controlled Growth Of Two-Dimensional Copper Nanoplates In Graphite Gallery, Xiaobei Bin, Jiazang Chen, Hong Cao
Turkish Journal of Chemistry
Copper nanoplates embedded in a graphite gallery were obtained by in situ reduction of stage 1, stage 2, and stage 3 CuCl_2-graphite intercalation compound precursors. The characterization results indicated that the morphology of the copper species was that of a 2-dimensional or quasi-2-dimensional nanoplate in the graphite gallery. Interaction between the metallic nanoplates and graphene sheet was also detected. The hexagonal graphene network restricted the crystallization orientation of the copper nanoparticles, and, at the same time, the finite space between the graphene sheets prevented the increase of the thickness. This method would provide a convenient route to synthesize or assemble …
Assimilable Organic Carbon Generation From Algogenic Organic Matter In Drinking Water, Ji-Hoon Kim, Young-Ju Kim, Tahir Imran Qureshi
Assimilable Organic Carbon Generation From Algogenic Organic Matter In Drinking Water, Ji-Hoon Kim, Young-Ju Kim, Tahir Imran Qureshi
Turkish Journal of Chemistry
A study of assimilable organic carbon (AOC) derived from algogenic organic matter in different drinking water resources was conducted. Seasonal changes in the concentration of AOC at Kamafusa Dam were dependent on the algal cell numbers. Variations in AOC concentrations were found to be more reliant on the AOC-P17 component than the AOC-NOX component. The algal culture experiment showed that extracellular organic matter (EOM) released during the growth of Phormidium tenue in M-11 culture medium led to a significant increase in AOC concentration; however, no significant variations of AOC concentration were observed in CT culture medium containing high amounts of …
Synthesis, Crystal Structure, And Antioxidant Properties Of Novel 1,2,4-Triazol-5-Ones Containing 3,4-Dimethoxyphenyl And 3,4-Dihydroxyphenyl Moiety, Yasemi̇n Ünver, Sevgi̇ Meydanal, Kemal Sancak, Di̇lek Ünlüer, Reşat Ustabaş, Esra Düğdü
Synthesis, Crystal Structure, And Antioxidant Properties Of Novel 1,2,4-Triazol-5-Ones Containing 3,4-Dimethoxyphenyl And 3,4-Dihydroxyphenyl Moiety, Yasemi̇n Ünver, Sevgi̇ Meydanal, Kemal Sancak, Di̇lek Ünlüer, Reşat Ustabaş, Esra Düğdü
Turkish Journal of Chemistry
A series of new 4-(3,4-dimethoxyphenethyl)-5-akyl/aryl-2H- 1,2,4-triazol-3(4H)-ones (3a-g) was obtained by the reaction of ethyl 2-(ethoxy)(alkylidene/arylidene)hydrazinecarboxylate (1) and 2-(3,4-dimethoxyphen- yl)ethanamine (2). Compounds 4a-f and 5 were synthesized from the reaction of corresponding compounds 3a-f and 3g with BBr_3, respectively. With elemental analysis, IR, ^1H-NMR, and ^{13C-NMR spectral data, 14 newly synthesized compounds were characterized. The structure of compound 3a was inferred through IR, ^1H- and ^{13}C-NMR, elemental analysis, and X-ray spectral techniques. In addition, the newly synthesized chemicals were screened for their antioxidant properties. Among the chemicals tested, 4a, 4c, 4d, 4f, and 5 exhibited the highest degree of antioxidant activity.
Synthesis And Properties Of New Optically Active And Organosoluble Poly(Ester-Imide)S Containing L-Valine Moieties In The Main Chain By Direct Polycondensation Reaction, Khalil Faghihi, Meisam Shabanian, Mohsen Hajibeygi
Synthesis And Properties Of New Optically Active And Organosoluble Poly(Ester-Imide)S Containing L-Valine Moieties In The Main Chain By Direct Polycondensation Reaction, Khalil Faghihi, Meisam Shabanian, Mohsen Hajibeygi
Turkish Journal of Chemistry
New optically active poly(ester-imide)s (PEIs) containing bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic diimide in the main chain were prepared by the reaction of N,N'-(bicyclo[2,2,2]oct-7- ene-2,3,5,6-tetra carboxylic)-bis-L-valine 4 as a diacid monomer with various aromatic diols 5a-g in a system of tosyl chloride (TsCl), pyridine (Py), and N,N-dimethylformamide (DMF). The reactions with TsCl were significantly promoted by controlling alcoholysis with diols, in the presence of catalytic amounts of DMF, to give a series of optically active poly(ester-imide)s. The resulting new polymers were obtained in good yields and inherent viscosities, ranging between 0.36 and 0.62 dL g^{-1}, and were characterized with FT-IR and ^1H-NMR spectroscopy, including specific …
Molecular Modeling And Antimycobacterial Studies Of Mannich Bases: 5-Hydroxy-2-Methyl-4h-Pyran-4-Ones, Barkin Berk, Demet Us, Si̇nem Öktem, Zühtü Tanil Kocagöz, Berrak Çağlayan, Işil Aksan Kurnaz, Di̇lek Demi̇r Erol
Molecular Modeling And Antimycobacterial Studies Of Mannich Bases: 5-Hydroxy-2-Methyl-4h-Pyran-4-Ones, Barkin Berk, Demet Us, Si̇nem Öktem, Zühtü Tanil Kocagöz, Berrak Çağlayan, Işil Aksan Kurnaz, Di̇lek Demi̇r Erol
Turkish Journal of Chemistry
The World Health Organization lists tuberculosis among the top 3 leading causes of death from a single infectious agent, and reported cases of multidrug-resistant tuberculosis (MDR-TB) are on the rise. In an attempt to improve MDR-TB drug-directed therapy, we synthesized 11 4-substituted piperazine derivatives of 3-hydroxy-6-methyl-4H-pyran-4-one pharmacophore by reacting 5-hydroxy-2-methyl-4H-pyran-4-one with suitable piperazine derivatives under Mannich reaction conditions. Inhibitory effects of the 11 compounds on Escherichia coli DNA gyrase were evaluated via DNA gyrase supercoiling assay. The minimum inhibitory concentrations (MIC) of the 11 compounds and 41 compounds from our previous studies against Mycobacterium tuberculosis H37RV were assessed, in vitro, …
Synthesis And In Vitro Antimycobacterial Activities Of Novel 6-Substituted-3(2h)-Pyridazinone-2-Acetyl-2-(Substituted/ Nonsubstituted Acetophenone) Hydrazone, Semra Utku, Mehtap Gökçe, Gönül Aslan, Gül Bayram, Mahmut Ülger, Gürol Emekdaş, Mustafa Fethi̇ Şahi̇n
Synthesis And In Vitro Antimycobacterial Activities Of Novel 6-Substituted-3(2h)-Pyridazinone-2-Acetyl-2-(Substituted/ Nonsubstituted Acetophenone) Hydrazone, Semra Utku, Mehtap Gökçe, Gönül Aslan, Gül Bayram, Mahmut Ülger, Gürol Emekdaş, Mustafa Fethi̇ Şahi̇n
Turkish Journal of Chemistry
The difficulty in managing tuberculosis includes the prolonged duration of the treatment, the emergence of drug resistance, and coinfection with HIV/AIDS. Tuberculosis control requires new drugs that act on novel drug targets to help in combating resistant forms of Mycobacterium tuberculosis and reduce the treatment duration. For this purpose, 6-substituted-3(2H)-pyridazinone-2-acetyl-2- (substituted/nonsubstituted acetophenone) hydrazone derivatives were synthesized and their structures were elucidated by elemental analyses, IR, and ^1H-NMR. The in vitro antimycobacterial activities of synthesized compounds 5a-l were determined by the agar proportion method against Mycobacterium tuberculosis H37Rv. Among the target compounds, 5b and 5f exhibited the best antimycobacterial activity, with …
E)--2--Acetyl--4--(4--Methoxyphenyldiazenyl) Phenol: X--Ray And Dft--Calculated Structure, Serap Yazici, Çi̇ğdem Albayrak, İsmai̇l Erdem Gümrükçüoğlu, İsmet Şenel, Orhan Büyükgüngör
E)--2--Acetyl--4--(4--Methoxyphenyldiazenyl) Phenol: X--Ray And Dft--Calculated Structure, Serap Yazici, Çi̇ğdem Albayrak, İsmai̇l Erdem Gümrükçüoğlu, İsmet Şenel, Orhan Büyükgüngör
Turkish Journal of Chemistry
The crystal structure of the title compound, (E)-2-acetyl-4-(4-methoxyphenyldiazenyl) phenol, displays a trans configuration of the azo moiety as found for other azo (diazene) derivatives. The aromatic mean planes are nearly coplanar and the dihedral angle between the 2 aromatic rings is 3.04(8)°. The molecules, with strong intramolecular O--H...O hydrogen bonding, are linked by weak van der Waals interactions in the 3-dimensional network. The molecular geometry, determined using X-ray diffraction techniques, was also calculated with the density functional theory (DFT), employing the hybrid exchange-correlation functional B3LYP. Experimental and theoretical IR spectra of the compound were also calculated for comparison. The results …
Electrocatalytic Oxidation Of Ethanol On Various Metal Ad-Layer Modified Au(111) Electrodes In Alkaline Solution, Zekerya Dursun, Şükri̇ye Ulubay Karabi̇beroğlu, Buket Gelmez, Aydan Başaran
Electrocatalytic Oxidation Of Ethanol On Various Metal Ad-Layer Modified Au(111) Electrodes In Alkaline Solution, Zekerya Dursun, Şükri̇ye Ulubay Karabi̇beroğlu, Buket Gelmez, Aydan Başaran
Turkish Journal of Chemistry
Ethanol oxidation was studied on single-crystal Au(111) electrodes that were modified by platinum, palladium, and cadmium metal ad-layers. The metal ad-layer modification was carried out by the underpotential deposition process, in which controlled amounts of Pt, Pd, and Cd were electrodeposited onto the substrate as submonolayer or monolayer coverage. The activity of the metal ad-layer modified Au(111) electrodes toward ethanol oxidation was studied in alkaline media, and recorded voltammograms were compared to those of bare single crystal Au(111) and polycrystalline gold and platinum disk electrodes. In terms of the desired shift in reduction potential and increased current density, the best …
Tridentate Ligands Derived From L-Tert-Leucine For The Cu(Ii) Mediated Asymmetric Henry Reaction, Nesli̇han Korkmaz, Demet Astley, Stephen Thomas Astley
Tridentate Ligands Derived From L-Tert-Leucine For The Cu(Ii) Mediated Asymmetric Henry Reaction, Nesli̇han Korkmaz, Demet Astley, Stephen Thomas Astley
Turkish Journal of Chemistry
Chiral tridentate Schiff base ligands were prepared from L-tert-Leucine and used as catalysts in the asymmetric Henry reaction in the presence of Cu(II) ions. Moderate enantiomeric excesses (up to 66%) and yields (up to 76%) of the desired \beta-nitroalcohols were obtained.
Zno Nanoflake Arrays Prepared Via Anodization And Their Performance In The Photodegradation Of Methyl Orange, Huey-Shya Goh, Rohana Adnan, Muhammad Akhyar Farrukh
Zno Nanoflake Arrays Prepared Via Anodization And Their Performance In The Photodegradation Of Methyl Orange, Huey-Shya Goh, Rohana Adnan, Muhammad Akhyar Farrukh
Turkish Journal of Chemistry
In the present work, anodization of zinc foil was investigated in a mixed electrolyte of ammonium sulfate and sodium hydroxide under the influence of different anodization times and concentrations of the electrolyte while the temperature and voltage were kept constant. The ZnO nanoflake arrays formed on Zn foil were characterized using a field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX) analysis, and X-ray diffraction (XRD). The size of the nanoflakes increased as the anodization time increased, while increasing the concentration of (NH_4)_2SO_4 increased the dissolution of the nanoflakes. Upon stirring, the nanoflakes that formed were more uniform …
One Pot Synthesis Of Pyridophenanthroline And Pyrrolophenanthroline Derivatives By Regioselective Reaction Between 1,7-Phenanthroline And Dialkyl Acetylenedicarboxylate: New Fused Heterocyclic Compounds, Malek Taher Maghsoodlou, Reza Heydari, Sayyed Mostafa Habibi Khorassani, Batool Tahami Pour, Ghasem Marandi, Farhad Maghfuri
One Pot Synthesis Of Pyridophenanthroline And Pyrrolophenanthroline Derivatives By Regioselective Reaction Between 1,7-Phenanthroline And Dialkyl Acetylenedicarboxylate: New Fused Heterocyclic Compounds, Malek Taher Maghsoodlou, Reza Heydari, Sayyed Mostafa Habibi Khorassani, Batool Tahami Pour, Ghasem Marandi, Farhad Maghfuri
Turkish Journal of Chemistry
1,7-Phenanthroline reacts with dialkyl acetylenedicarboxylate in a regioselective manner to give new macromolecules such as tetramethyl- 6aH-pyrido[1,2-i][1,7]phenanthroline-7,8,9,10-tetracarboxylate and trialkyl pyrrolo[1,2-i][1,7]phenanthroline-7,8,9-tricarboxylate derivatives.
Synthesis And Antimicrobial Activity Of Methoxy Azachalcones And N-Alkyl Substituted Methoxy Azachalconium Bromides, Canan Albay, Nuran Kahri̇man, Nagi̇han Yilmaz İskender, Şengül Alpay Karaoğlu, Nuretti̇n Yayli
Synthesis And Antimicrobial Activity Of Methoxy Azachalcones And N-Alkyl Substituted Methoxy Azachalconium Bromides, Canan Albay, Nuran Kahri̇man, Nagi̇han Yilmaz İskender, Şengül Alpay Karaoğlu, Nuretti̇n Yayli
Turkish Journal of Chemistry
In this study, 18 new N-octyl, N-decyl, and N-dodecyl substituted o-, m-, and p-methoxy (E)-3- and 4-azachalcones, {4- or 3-[(1E)-3-(4-, 3-, or 2-methoxyphenyl)-3-oxoprop-1-en-1-yl]-1-alkyl (C_{8,10,12}) pyridinium bromides} (1a-6a, 1b-1b, and 1c-6c), and 4 new o-, and m-methoxy (E)-3- and 4-azachalcones (2, 3, 5, and 6) were synthesized and tested for antimicrobial activities against Escherichia coli, Yersinia pseudotuberculosis, Enterobacter aerogenes, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Bacillus cereus, and Candida albicans. N-Alkyl substituted azachalconium bromides showed good antimicrobial activity against all tested microorganisms with minimal inhibitory concentration (MIC) values in the range of 0.42-58.7 \mu g/mL in most cases. Nonalkylated compounds 1-9 …