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Articles 7561 - 7590 of 10319
Full-Text Articles in Physical Sciences and Mathematics
Oscillation Of Nonlinear Neutral Delay Differential Equations Of Second-Order With Positive And Negative Coefficients, Mustafa Kemal Yildiz, Başak Karpuz, Özkan Öcalan
Oscillation Of Nonlinear Neutral Delay Differential Equations Of Second-Order With Positive And Negative Coefficients, Mustafa Kemal Yildiz, Başak Karpuz, Özkan Öcalan
Turkish Journal of Mathematics
Some oscillation criteria for the following second-order neutral differential equation [x(t)\pm r(t) f( x(t-\gamma))]''+p(t) g(x(t-\alpha)) -q(t) g(x(t-\beta )) = s(t) where t\geq t_0, \gamma,\alpha,\beta \in R^+ with \alpha \geq \beta, r \in C^2([t_0,\infty ), R^+) , p,q\in C([t_0,\infty ),R^+) and f,g\in C(R,R), s\in C([ t_0,\infty),R) have been obtained. Our results are not restricted with boundedness of solutions.
Solutions For 2n^{Th} Order Lidstone Bvp On Time Scales, Erbi̇l Çeti̇n, S. Gülşan Topal
Solutions For 2n^{Th} Order Lidstone Bvp On Time Scales, Erbi̇l Çeti̇n, S. Gülşan Topal
Turkish Journal of Mathematics
In this paper, we prove the existence of solutions for nonlinear Lidstone boundary value problems by using the monotone method on time scale and also we show the existence of at least one positive solution if f is either superlinear or sublinear by the fixed point theorem in a Banach space.
A Perturbation Of M-Order Derivations On Banach Algebras, Yong-Soo Jung, Kyoo-Hong Park
A Perturbation Of M-Order Derivations On Banach Algebras, Yong-Soo Jung, Kyoo-Hong Park
Turkish Journal of Mathematics
Let \A be a unital Banach algebra and let m, 1 \leq m \leq 4, be an integer. If f: \A \to \A is an approximate m-order derivation in the sense of Hyers-Ulam-Rassias, then f: \A \to \A is an exact m-order derivation.
On Completeness Of Elementary Generalized Solutions Of A Class Of Operator-Differential Equations Of A Higher Order, Rovshan Z. Gumbataliev
On Completeness Of Elementary Generalized Solutions Of A Class Of Operator-Differential Equations Of A Higher Order, Rovshan Z. Gumbataliev
Turkish Journal of Mathematics
In this paper we give definition of m-fold completeness and prove a theorem on completeness of elementary generalized solution of corresponding boundary value problems at which the equation describes the process of corrosive fracture of metals in aggressive media and the principal part of the equation has multiple characteristics.
Insulation Condition Assessment Of Power Transformers Using Accelerated Ageing Tests, Mohammad Mirzaie, Ahmad Gholami, Hamid Reza Tayebi
Insulation Condition Assessment Of Power Transformers Using Accelerated Ageing Tests, Mohammad Mirzaie, Ahmad Gholami, Hamid Reza Tayebi
Turkish Journal of Electrical Engineering and Computer Sciences
Thermal stress due to losses and environment temperature causes degradation to paper/oil insulation systems in transformers, even at operating temperature. Experience indicates that thermal ageing of oil and paper in power transformers leads to the change of some insulation characteristics. In this paper, insulating papers immersed in oil have been acceleratory aged at 140, 150, and 160 °C under laboratory conditions. Some of the oil properties, such as water content, breakdown voltage, acidity, together with the aged insulating paper properties such as electric strength, dielectric dissipation factor and tensile strength were measured and analyzed. Also, insulation system conditions under thermal …
Voltage Control Of Self-Excited Induction Generator Using Genetic Algorithm, Dheeraj Joshi, Kanwarjit Singh Sandhu, Mahender Kumar Soni
Voltage Control Of Self-Excited Induction Generator Using Genetic Algorithm, Dheeraj Joshi, Kanwarjit Singh Sandhu, Mahender Kumar Soni
Turkish Journal of Electrical Engineering and Computer Sciences
Self-excited induction generators (SEIG) are found to be most suitable candidate for wind energy conversion application required at remote windy locations. Such generators are not able to maintain the terminal voltage with load as, a literature survey reveals, the voltage profile falls sharply with load. In this paper an attempt has been made to improve the voltage profile of a self-excited induction generator. A new methodology based upon Genetic Algorithm (GA) is proposed to compute the steady state performance of the model including core loss branch. Further efforts are made to control the terminal voltage under loaded conditions. Simulated results …
Variance And Kurtosis-Based Characterization Of Resonances In Stochastic Transmission Lines: Local Versus Global Random Geometries, Ousmane Sy, Martijn Van Beurden, Bastiaan Michielsen, Antonius Tijhuis
Variance And Kurtosis-Based Characterization Of Resonances In Stochastic Transmission Lines: Local Versus Global Random Geometries, Ousmane Sy, Martijn Van Beurden, Bastiaan Michielsen, Antonius Tijhuis
Turkish Journal of Electrical Engineering and Computer Sciences
A stochastic method is proposed to characterize electromagnetic couplings involving geometrically perturbed transmission lines. A combined exploitation of suitably defined statistical tools is presented to appreciate the intensity of the dispersion of response variables both physically via the variance, and statistically through the kurtosis or fourth-order moment. The usefulness of this method to analyze resonances is illustrated by the study of a transmission line affected by two different types of random geometrical perturbations, viz. a local deformation modeled by a wavelet and global sinusoidal undulations.
Electronic Differential With Direct Torque Fuzzy Control For Vehicle Propulsion System, Kada Hartani, Mohamed Bourahla, Yahia Miloud, Mohamed Sekour
Electronic Differential With Direct Torque Fuzzy Control For Vehicle Propulsion System, Kada Hartani, Mohamed Bourahla, Yahia Miloud, Mohamed Sekour
Turkish Journal of Electrical Engineering and Computer Sciences
We model an electronic differential that will offer the best vehicle stability on a curved road. The proposed traction system consists of two permanent magnet synchronous (PMS) machines that ensure the drive of two back-driving wheels. The contribution of each wheel to the advance of the vehicle is represented by an element conveying the accumulation of mechanical coupling. The proposed control structure is based on the direct torque fuzzy control for each wheel-motor. Different simulations have been carried out: vehicle driven ons straight road, vehicle driven on straight road with slope, and vehicle driven over a road curved left and …
Conductive Emi Noise Measurement For Switched Reluctance Drive, Hao Chen, Xiaohui Qiu, Yang Zhao
Conductive Emi Noise Measurement For Switched Reluctance Drive, Hao Chen, Xiaohui Qiu, Yang Zhao
Turkish Journal of Electrical Engineering and Computer Sciences
The component parts of the tested four-phase Switched Reluctance drive are described with the four-phase 8/6 structure double salient reluctance motor, the four-phase asymmetric bridge power converter and the 89C52 MCU digital controller. The conductive electromagnetic interference noise measurement equipment is described with the function of separated common-mode noise and differential-mode noise. The tested results of common-mode noise and differential-mode noise of the tested Switched Reluctance drive are presented and the tested results of frequency spectrum are given.
6-Ketomethyl Phenanthridine As A New Carrier In The Construction Of A Highly Selective Fe(Iii) Ion-Selective Membrane Electrode, R. Maleki, Reza Hosseinzadeh, Hossein Mehrabi, Ali Hassanzadeh, Khalil Farhadi
6-Ketomethyl Phenanthridine As A New Carrier In The Construction Of A Highly Selective Fe(Iii) Ion-Selective Membrane Electrode, R. Maleki, Reza Hosseinzadeh, Hossein Mehrabi, Ali Hassanzadeh, Khalil Farhadi
Turkish Journal of Chemistry
A new Fe^{3+} ion-selective membrane electrode based on 6-ketomethyl phenanthridine (6-KMPT) and 1-(4-dimethyl aminophenyl)-2-(5H-phenanthridine-6-ylidene)-ethanone, which were incorporated in a plasticized polyvinyl chloride (PVC) membrane, is described. The optimized membrane demonstrated a linear dynamic range of 5.2 \times 10^{-6}-1.0 \times 10^{-2} M, with a near Nernstian slope of 19.5 \pm 1.5 mV per decade and a detection limit of 1.2 \times 10^{-6} M. The electrode showed high selectivity for Fe^{3+} ions in comparison to other metal ions. The effect of membrane composition on the potential response of the electrode was studied. The best performance was observed for the membrane comprised of …
On The Structure Sensitivity Of Co Oxidation On Alumina Supported Pd--Pt Bimetallic Catalysts, Sarp Kaya, Ebru Erunal, Riad Shaltaf, Şi̇nasi̇ Elli̇altioğlu, Deni̇z Üner
On The Structure Sensitivity Of Co Oxidation On Alumina Supported Pd--Pt Bimetallic Catalysts, Sarp Kaya, Ebru Erunal, Riad Shaltaf, Şi̇nasi̇ Elli̇altioğlu, Deni̇z Üner
Turkish Journal of Chemistry
CO oxidation reaction was studied over monometallic and bimetallic palladium--platinum catalysts at 25:75, 50:50, and 75:25 Pd:Pt atomic fractions co-impregnated over a \gamma -Al_2O_3 support. The size of the metal particles, measured by modified hydrogen chemisorption, increased as the Pd fractions in the catalyst increased. The surface compositions and site metal distributions of the catalysts determined from Monte Carlo simulations indicated that Pd atoms segregated to the surface: at low Pd levels, Pd occupied preferentially 6 and 7 coordinated defect-like sites. As the Pd fraction increased, first 8 coordinated (100) and then 9 coordinated (111) planes were populated. At low …
A Facile Method For The Preparation Of Poly(4-Vinylpyridine) Nanoparticles And Their Characterization, Nurettin Sahiner
A Facile Method For The Preparation Of Poly(4-Vinylpyridine) Nanoparticles And Their Characterization, Nurettin Sahiner
Turkish Journal of Chemistry
Submicron size particles were synthesized from 4-vinylpyridine (4-VP) using an oil-in-water emulsion system. Divinyl benzene (DVB) and ethylene glycol dimethacrylate (EGDMA) were utilized as crosslinkers for the synthesis of p(4-VP) hydrogel nanoparticles in sodium dodecyl sulfate (SDS) surfactant systems. Characterization of the particles was made by transmission electron microscopy (TEM) and dynamic light scattering (DLS) methods. To render a positive charge, p(4-VP) particles were reacted with 1-bromo butane (1-BB).
Synthesis And Leishmanicidal Evaluation Of Novel 4-Substituted-2,2-Dimethyl-7-(Prop-2-Ynyloxy)Chromenes, Babak H. Alizadeh, Alireza Foroumadi, Susan K. Ardestani, Fatemeh Poorrajab, Abass Shafiee
Synthesis And Leishmanicidal Evaluation Of Novel 4-Substituted-2,2-Dimethyl-7-(Prop-2-Ynyloxy)Chromenes, Babak H. Alizadeh, Alireza Foroumadi, Susan K. Ardestani, Fatemeh Poorrajab, Abass Shafiee
Turkish Journal of Chemistry
Substituted 4-chromenes were synthesized via the Grignard coupling reaction of various substituted phenyl- and benzylmagnesium chlorides with 2,2-dimethyl-7-(prop-2-ynyloxy)chroman-4-one (1) in relatively good yield (60%-85%). The benzylic-substituted derivatives were a mixture of 2 exo and endo regioisomers, and the exo compounds were a mixture of E and Z isomers. Structural analysis of the exo and endo isomers, as well as E and Z of exo isomers were based on H-NMR, ^{13}C-NMR, and NOESY experiments. The synthetic compounds were examined for in vitro activity against Leishmania major and compound 9 (a, b) was the most active, with inhibitory activity of 36%.
Ctab-Assisted Hydrothermal Synthesis And Magnetic Characterization Of Ni_Xco_{1-X}Fe_2o_4 Nanoparticles (X = 0.0, 0.6, 1.0), Abdulhadi̇ Baykal, Nermi̇n Kasapoğlu, Zehra Durmuş, Hüseyi̇n Kavas, Muhammet S. Toprak, Yüksel Köseoğlu
Ctab-Assisted Hydrothermal Synthesis And Magnetic Characterization Of Ni_Xco_{1-X}Fe_2o_4 Nanoparticles (X = 0.0, 0.6, 1.0), Abdulhadi̇ Baykal, Nermi̇n Kasapoğlu, Zehra Durmuş, Hüseyi̇n Kavas, Muhammet S. Toprak, Yüksel Köseoğlu
Turkish Journal of Chemistry
Nickel ferrite, Ni_xCo_{1-x}Fe_2O_4, NPs (where x = 0.0, 0.6 and 1.0) were successfully synthesized by a rapid and reproducible CTAB-assisted hydrothermal route. The influence of different hydrolyzing agents on the particle size and magnetic behavior of Ni_xCo_{1-x}Fe_2O_4 NPs was investigated. Particles showed very high phase purity and crystallinity in powder XRD analysis. Compositions of Co, Fe, and Ni in fabricated powders were also determined by AAS and results are in very good agreement with the targeted compositions. Samples hydrolyzed using NH_3 showed no significant changes in the particle size and morphology. NH_3 hydrolyzed samples were much smaller than their NaOH …
Mild And Efficient Iodination Of Aromatic Compounds With Trichloroisocyanuric Acid/I_2/Wet Sio_2 System, Batool Akhlaghinia, Marzieh Rahmani
Mild And Efficient Iodination Of Aromatic Compounds With Trichloroisocyanuric Acid/I_2/Wet Sio_2 System, Batool Akhlaghinia, Marzieh Rahmani
Turkish Journal of Chemistry
Iodoarenes can be obtained using trichloroisocyanuric acid/I_2/wet SiO_2 system at room temperature with high yield in CH_2Cl_2.
Silver Ion-Assisted Ring Expansions In Different Solvent Systems, Mesut Boz, Hafi̇ze Çalişkan, Ömer Zai̇m
Silver Ion-Assisted Ring Expansions In Different Solvent Systems, Mesut Boz, Hafi̇ze Çalişkan, Ömer Zai̇m
Turkish Journal of Chemistry
Several ring expansion products carrying vinylic bromo functionality were synthesized by opening of the geminal dibromobicyclo[n.1.0]alkanes ring. Dibromocarbene was formed from bromoform and potassium tert-butoxide in hexane. Its reaction with various cyclic alkenes was the resultant dibromobicyclo[n.1.0]alkanes. Then, opening was performed using AgNO_3 in various solvent systems, such as acetic acid/DMSO, acetic acid/DMF, CH_3OH/acetone, and H_2O/DMF.
Bromination Of Tetrachlorobenzobarrelene: Polyhalogenated Benzobicyclics, Mehmet Emi̇n Şengül, Demet Demi̇rci̇ Gülteki̇n, Selçuk Eşsi̇z, Ari̇f Daştan
Bromination Of Tetrachlorobenzobarrelene: Polyhalogenated Benzobicyclics, Mehmet Emi̇n Şengül, Demet Demi̇rci̇ Gülteki̇n, Selçuk Eşsi̇z, Ari̇f Daştan
Turkish Journal of Chemistry
The low and high temperature bromination reaction of tetrachlorobenzobarrelene was studied and the possible role of a neighboring group in rearrangements was investigated. New polyhalogenated benzobicyclic compounds were synthesized. All compounds were characterized properly using NMR spectroscopy.
Rapid Synthesis Of New Poly(Amide-Imide)S Based On N-(4-Carboxy Phenyl) Trimellitimide And Hydantoin Derivatives Under Microwave Irradiation, Khalil Faghihi, Mohammad Gholizadeh
Rapid Synthesis Of New Poly(Amide-Imide)S Based On N-(4-Carboxy Phenyl) Trimellitimide And Hydantoin Derivatives Under Microwave Irradiation, Khalil Faghihi, Mohammad Gholizadeh
Turkish Journal of Chemistry
Six new poly (amide-imide)s (6a-f) were prepared under microwave irradiation by polycondensation reaction of diacid chloride (4) with 6 different derivatives of hydantoins (5a-f) using O-cresol as a microwave absorbent. These new PAIs were obtained in high yield and with inherent viscosities between 0.15 and 0.25 dL/g. The resulting poly(amide-imide)s were characterized by elemental analysis, viscosity measurements, thermal gravimetric analysis (TGA & DTG), solubility test, and FT-IR spectroscopy. N-(4-chlorocarbonyl phenyl) trimellitimide acid chloride (4) was prepared by a 2-step reaction. First trimellitic anhydride (1) was reacted with 4-amino benzoic acid (2) in acetic acid solution and the resulting imide-acid [N-(4-carboxy …
Synthesis And Characterization Of Tetraoxime Ligand, Bis-[(2e,3e,2´E)-3,3´-(1,2-Phenylene-Dinitrilo)Dibutan-2-One Dioxime] And Its Dinuclear And Tetranuclear Copper(Ii)/Nickel(Ii) Complexes, Nevi̇n Karaböcek, Pinar Ekmekçi̇oğlu, Asligül Küçükdumlu, Serdar Karaböcek
Synthesis And Characterization Of Tetraoxime Ligand, Bis-[(2e,3e,2´E)-3,3´-(1,2-Phenylene-Dinitrilo)Dibutan-2-One Dioxime] And Its Dinuclear And Tetranuclear Copper(Ii)/Nickel(Ii) Complexes, Nevi̇n Karaböcek, Pinar Ekmekçi̇oğlu, Asligül Küçükdumlu, Serdar Karaböcek
Turkish Journal of Chemistry
A new tetraoxime, (H_4L), was prepared in EtOH by reacting biphenyl-3,3´,4,4´-tetramine with butane-2,3-dione oxime. The tetraoxime ligand was characterized by elemental analyses, H-NMR and ^{13}C-NMR, IR, and mass spectral studies. Dinuclear copper(II), nickel(II) and tetranuclear copper(II) complexes of tetraoxime ligand were prepared and characterized by elemental analyses, magnetic moments, IR, and mass spectral studies. In the dinuclear metal complexes, metal:ligand ratio was found as 2:1. Elemental analyses and stoichiometric and spectroscopic data of the metal complexes indicated that the metal ions were coordinated to the nitrogen atoms of oxime groups (C=N). In addition, total energy and heat formation for ligand …
Nitric Oxide Releasing Derivatives Of [(2-Chloroethyl)Ureido] Benzoic Acid Esters As Potential Antineoplastic Agents, Hülya Akgün, Barkin Berk, Di̇lek Demi̇r Erol, Güldem Mercanoğlu, Ömer Faruk Bayrak, Berrak Çağlayan, Asli Dedeağaç, Işil Aksan Kurnaz
Nitric Oxide Releasing Derivatives Of [(2-Chloroethyl)Ureido] Benzoic Acid Esters As Potential Antineoplastic Agents, Hülya Akgün, Barkin Berk, Di̇lek Demi̇r Erol, Güldem Mercanoğlu, Ömer Faruk Bayrak, Berrak Çağlayan, Asli Dedeağaç, Işil Aksan Kurnaz
Turkish Journal of Chemistry
New series of [(2-chloroethyl)ureido] benzoic acids (compounds 3-8) and nitric oxide releasing derivatives of [(2-chloroethyl)ureido] benzoic acid esters (compounds 9-14) were synthesized as potential anti-cancer agents. These compounds were screened for their anti-proliferative activities on A549 (human lung carcinoma) cells and for their cytotoxic effects on L929 (mouse fibroblast) cells. The compounds 3-8 exhibited mild cytotoxic effects on L929 cells (cell viability from 100% to 85% -- 90% only) whereas they had very little anti-proliferative activities towards A549 lung carcinoma cells. On the other hand, compounds 10, 11, and 13 had some growth inhibition activity in A549 (human lung carcinoma) …
Microwave-Assisted Synthesis Of Some Metal-Free Phthalocyanine Derivatives And A Comparison With Conventional Methods Of Their Synthesis, Özlem Seven, Bi̇rcan Di̇ndar, Burak Gülteki̇n
Microwave-Assisted Synthesis Of Some Metal-Free Phthalocyanine Derivatives And A Comparison With Conventional Methods Of Their Synthesis, Özlem Seven, Bi̇rcan Di̇ndar, Burak Gülteki̇n
Turkish Journal of Chemistry
Synthesis of metal-free 2,9(10),16(17),23(24)-tetra(3,5- dimethylphenoxy) phthalocyanine, 2,9(10),16(17), 23(24)-tetra(4- tert-butylphenoxy) phthalocyanine, and 2,9(10),16(17),23(24)-tetra(3,5- di-tert-butyl-4-hydroxyphenyl) phthalocyanine was carried out via microwave irradiation. Furthermore, pentanol and lithium were used for the first time in the synthesis of metal-free phthalocyanine under microwave irradiation as a solvent and a base-catalyst, respectively. The microwave irradiation experiments were performed in a MARS5 with a CEM XP-1500 vessel. In addition, these compounds were obtained with conventional heating procedures to compare them with those obtained with microwave irradiation. The compounds were characterized by elemental and spectroscopic analysis, including UV-Vis, H NMR, FT-IR, and MALDI-TOF mass data. In particular, both …
Chiral Calixarenes, Abdulkadi̇r Sirit, Mustafa Yilmaz
Chiral Calixarenes, Abdulkadi̇r Sirit, Mustafa Yilmaz
Turkish Journal of Chemistry
No abstract provided.
Study Of The Polymerization Of Methyl Methacrylate Initiated By Thioxanthone Derivatives: A Magnetic Field Effect, Sevnur Keski̇n, Meral Aydin, Igor Khudyakov, Nergi̇z Arsu
Study Of The Polymerization Of Methyl Methacrylate Initiated By Thioxanthone Derivatives: A Magnetic Field Effect, Sevnur Keski̇n, Meral Aydin, Igor Khudyakov, Nergi̇z Arsu
Turkish Journal of Chemistry
Free radical photopolymerization of methyl methacrylate (MMA) initiated by 2-mercaptothioxanthone (TX-SH), thioxanthone-thioacetic acid (TXSCH_2COOH), and thioxanthone-carboxymethoxy acetic acid (TXOCH_2COOH) as so called one-component initiators was performed with and without an external magnetic field (MF). These initiators contain light-absorbing and electron/hydrogen-donating fragments in one molecule and do not require an additional hydrogen donor, and initiate the polymerization of MMA in the air. Polymerization experiments were performed in solutions with 3 different optical densities at \lambda 365 nm, where the photoinitiator absorbs. It was observed that application of MF leads to both larger conversion and higher molecular weight of the prepared PMMA, …
A Mild Method For The Cleavage Of Ketals Using Ibx, Abdul Rauf Raza
A Mild Method For The Cleavage Of Ketals Using Ibx, Abdul Rauf Raza
Turkish Journal of Chemistry
Investigation on the total synthesis of batrachotoxin 1 revealed that the cyclic ketals could be cleaved to ketone with IBX in DMSO at 70-81 °C under very mild conditions. A variety of functional groups showed no interference under these conditions except vinyl bromides, which, in fact, inhibits the single electron transfer to IBX.
Ferric Hydrogen Sulfate As An Efficient Heterogeneous Catalyst For Environmentally Friendly Greener Synthesis Of 1,8-Dioxo-Octahydroxanthenes, Hamid Reza Shaterian, Asghar Hosseinian, Majid Ghashang
Ferric Hydrogen Sulfate As An Efficient Heterogeneous Catalyst For Environmentally Friendly Greener Synthesis Of 1,8-Dioxo-Octahydroxanthenes, Hamid Reza Shaterian, Asghar Hosseinian, Majid Ghashang
Turkish Journal of Chemistry
Ferric hydrogen sulfate was used as an environmentally friendly heterogeneous acidic catalyst for the greener, 1-pot, 3-component synthesis of 1,8-dioxo-octahydroxanthene via condensation reactions between aromatic aldehydes and dimedone under solvent-free thermal and microwave irradiation as well as in aqueous media conditions in short periods of times with excellent yields. The catalyst was easily separated in simple work-up and was recycled several times without loss of reactivity under the described reaction conditions.
The Role Of The Entropy Factor On The Adsorption Of An Optical Brightener On Pulp, Greta Radeva, Eva Valcheva, Stefka Veleva
The Role Of The Entropy Factor On The Adsorption Of An Optical Brightener On Pulp, Greta Radeva, Eva Valcheva, Stefka Veleva
Turkish Journal of Chemistry
The present paper reports results of the thermodynamic study of adsorption of 2 optical brighteners (Tinopal UP and Leucophor AP) on pulp. The entropy non-homogeneity of the pulp surface was confirmed and the coefficients of entropy non-homogeneity were determined. The entropy effect on the variation of Gibbs free energy of the process studied was followed.
Water-Gas Shift Reaction Over Bimetallic Pt-Ni/Al_2o_3 Catalysts, Burcu Selen Çağlayan, Ahmet Erhan Aksoylu
Water-Gas Shift Reaction Over Bimetallic Pt-Ni/Al_2o_3 Catalysts, Burcu Selen Çağlayan, Ahmet Erhan Aksoylu
Turkish Journal of Chemistry
The water-gas shift (WGS) activity of bimetallic Pt-Ni/Al_2O_3 catalysts was investigated in the temperature range 200-450 °C using an idealized feed composition consisting of 3% CO and 6%-10% H_2O. The effects of the Ni content, space velocity, and H_2O/CO ratio on the catalytic performance of the catalysts were studied. An increase in the Ni content and H_2O/CO ratio shifted the carbon monoxide conversion--temperature curve toward lower reaction temperatures. No detectable methane formation was observed in the catalytic reaction tests. The results indicate that Pt-Ni/Al_2O_3 catalysts are highly selective and active for water-gas shift reactions under idealized conditions.
Synthesis, Spectral Characterization, And Antimicrobial Activity Of Arsenic(Iii) And Bismuth(Iii) Tri[3(2´-Hydroxyphenyl)-5-(4-Subsituted Phenyl)Pyrazolinates], Umesh Nath Tripathi, Afshan Siddqui, Jeeven Singh Solanki, Mohammad Safi Ahmad, Arpan Bhardwaj, Tulsi Ram Thapak
Synthesis, Spectral Characterization, And Antimicrobial Activity Of Arsenic(Iii) And Bismuth(Iii) Tri[3(2´-Hydroxyphenyl)-5-(4-Subsituted Phenyl)Pyrazolinates], Umesh Nath Tripathi, Afshan Siddqui, Jeeven Singh Solanki, Mohammad Safi Ahmad, Arpan Bhardwaj, Tulsi Ram Thapak
Turkish Journal of Chemistry
Arsenic(III) tripyrazolinates and bismuth(III) tripyrazolinates of the type M(C_{15}H_{12}N_2OX)_3 [where C_{15}H_{12}N_2OX = 3(2'-hydroxyphenyl)-5-(4-substituted phenyl)pyrazoline] have been synthesized by the reaction of MCl_3 and sodium salt of pyrazolines in 1:3 molar ratio in anhydrous benzene at elevated temperature. These newly synthesized derivatives have been characterized by elemental analysis (C, H, N, As, and Bi), molecular weight measurement, spectral [IR and multinuclear NMR (^1H & ^{13}C)] and x-ray diffraction studies. The bonding mode of pyrazolines and coordination no. of arsenic(III) and bismuth(III) in these derivatives have been discussed. Antibacterial and antifungal potential of free pyrazoline and some arsenic(III) tripyrazolinates and bismuth(III) tripyrazolinates …
Synthesis Of 5-Arylamino-1h (2h)-Tetrazoles And 5-Amino-1-Aryl-1h-Tetrazoles From Secondary Arylcyanamides In Glacial Acetic Acid: A Simple And Efficient Method, Ali Reza Modarresi-Alam, Mahmoud Nasrollahzadeh
Synthesis Of 5-Arylamino-1h (2h)-Tetrazoles And 5-Amino-1-Aryl-1h-Tetrazoles From Secondary Arylcyanamides In Glacial Acetic Acid: A Simple And Efficient Method, Ali Reza Modarresi-Alam, Mahmoud Nasrollahzadeh
Turkish Journal of Chemistry
A simple and efficient method for the preparation of 5-arylamino-1H (2H)-tetrazoles (3a-i) and 5-amino-1-ary-1H-tetrazoles (4a-i), with excellent yields and high purity, from secondary arylcyanamides (1a-i) at room temperature in glacial acetic acid is described. Tautomers 3a-i were separated from tautomers 4a-i by crystallization in ethanol. A mechanism was introduced in glacial acetic acid. The ratio of isomers is described based on the electronic and steric effects of various substituents. The electron withdrawing group (-NO_2) increased the ratio of 4:3. The rate of product formation was enhanced by introducing electron donating substituents. ^1H-NMR and ^{13}C-NMR chemical shifts and multiplicities are also …
Development Of Alumina Supported Alkaline Catalysts Used For Biodiesel Production, Oğuzhan İlgen, Ayşe Ni̇lgün Akin
Development Of Alumina Supported Alkaline Catalysts Used For Biodiesel Production, Oğuzhan İlgen, Ayşe Ni̇lgün Akin
Turkish Journal of Chemistry
The transesterification of canola oil with methanol was studied in a heterogeneous system, using \gamma-Al_2O_3 supported alkaline catalysts. All the catalysts were prepared by incipient-wetness impregnation of an aqueous solution of alkaline compounds on \gamma-Al_2O_3 support. The effects of alkaline compound, methanol/canola oil molar ratio, reaction temperature, catalyst amount, and reaction time in biodiesel production were investigated. The catalyst with KOH loaded on \gamma-Al_2O_3 gave the highest basicity and the best catalytic activity for this reaction. The highest FAME yield obtained was 89.40%.