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Articles 6661 - 6690 of 6946
Full-Text Articles in Entire DC Network
Frictions As A Constraint On Tax Planning, David M. Schizer
Frictions As A Constraint On Tax Planning, David M. Schizer
Faculty Scholarship
The government often uses narrow tax reforms to target specific planning strategies. Sometimes the targeted transaction is stopped. But in other cases, taxpayers press on, tweaking the deal just enough to sidestep the reform. The difference often lies in transaction costs, financial accounting, and other 'frictions, " which are constraints on tax planning external to the tax law.
This Article contributes a methodology for determining whether frictions will block end runs, and illustrates the effect of frictions by comparing the constructive sale rule of section 1259 with the constructive ownership rule of section 1260. These reforms use the same statutory …
Unocal Fifteen Year Later (And What We Can Do About It), Ronald J. Gilson
Unocal Fifteen Year Later (And What We Can Do About It), Ronald J. Gilson
Faculty Scholarship
The coincidence of the new millennium and the fifteenth anniversary of the Delaware Supreme Court's announcement of a new approach to takeover law provides an occasion to evaluate a remarkable experiment in corporate law – the Delaware Supreme Court's development of an intermediate standard of review for appraising defensive tactics. This assessment reveals that Unocal has developed into an unexplained and likely inexplicable preference that control contests be resolved through elections rather than through market transactions. In doing so, the remarkable struggle between the chancery court and the supreme court for Unocal's soul is canvassed. The author also maintains that …
Nonlinear Dynamics In Psychology, Stephen J. Guastello
Nonlinear Dynamics In Psychology, Stephen J. Guastello
Psychology Faculty Research and Publications
This article provides a survey of the applications of nonlinear dynamical systems theory to substantive problems encountered in the full scope of psychological science. Applications are organized into three topical areas – cognitive science, social and organizational psychology, and personality and clinical psychology. Both theoretical and empirical studies are considered with an emphasis on works that capture the broadest scope of issues that are of substantive interest to psychological theory. A budding literature on the implications of NDS principles in professional practice is reported also.
Determination Of The Thermodynamic Properties Of Poly [2-(3-Phenyl-3-Methylcyclobutyl)-2-Hydroxyethyl Methacrylate-Co-Methacrylic Acid] At Infinite Dilution By Inverse Gas Chromatography, İsmet Kaya, Kadi̇r Demi̇relli̇
Determination Of The Thermodynamic Properties Of Poly [2-(3-Phenyl-3-Methylcyclobutyl)-2-Hydroxyethyl Methacrylate-Co-Methacrylic Acid] At Infinite Dilution By Inverse Gas Chromatography, İsmet Kaya, Kadi̇r Demi̇relli̇
Turkish Journal of Chemistry
Some thermodynamic quantities were obtained for the interactions of poly [2-(3-phenyl -3- methylcyclobutyl)-2-hydroxyethyl methacrylate-co-methacrylic acid] Poly (PCHEMA-co-MA) with alcohols, ketones, acetates, aromatics and n-alkanes by inverse gas chromatography in the temperature range of 150-180^oC. The specific retention volumes, Vg^o, weight fraction activity coefficients of solute probes at infinite dilution, \Omega_{1}^{\infty} and Flory-Huggins thermodynamic interaction parameters, \chi_{12}^{\infty} between polymers and solvents were determined. The partial molar free energy, \DeltaG_{1}^{\infty} , the partial molar heat of mixing, \DeltaH_{1}^{\infty} , at infinite dilution and the solubility parameters of the polymer, \delta_{2} , were calculated. The copolymer was characterized by ^1 H-NMR, FT-IR and …
Electrorheological Properties Of Suspensions Prepared From Polystyrene- Block- Polyisoprene Copolymer, Hali̇l İbrahi̇m Ünal, Yilmaz Yildirir, Mustafa Yavuz
Electrorheological Properties Of Suspensions Prepared From Polystyrene- Block- Polyisoprene Copolymer, Hali̇l İbrahi̇m Ünal, Yilmaz Yildirir, Mustafa Yavuz
Turkish Journal of Chemistry
Considerable scientific and industrial interest is currently being focused on a class of materials known as electrorheological (ER) fluids, which display remarkable rheological behaviour, being able to convert rapidly and repeatedly from a liquid to solid when an electric field (E) is applied or removed. In this article, the synthesis, characterization, partial hydrolysis and ER properties of polystyrene- block}-polyisoprene copolymer (COP) were investigated. The block copolymer was characterized by GPC, viscosity measurements, ^1 H-NMR and FTIR spectroscopies, particle size measurements, and elemental analysis. The polystyrene block of the copolymer was partially hydrolyzed by a series of chemical reactions and then …
The Sorption Of Metals On The Polysulfone Cation Exchange Membranes, Mustafa Ersöz, İlkay Hi̇lal Güğül, Aysel Çi̇men, Betül Leylek, Sali̇h Yildiz
The Sorption Of Metals On The Polysulfone Cation Exchange Membranes, Mustafa Ersöz, İlkay Hi̇lal Güğül, Aysel Çi̇men, Betül Leylek, Sali̇h Yildiz
Turkish Journal of Chemistry
The sorption of NaCl and CaCl_2 and monovalent-divalent cation salt mixtures on the polysulfone and polysulfone with polyester support cation exchange membranes were investigated. The sorption of monovalent-divalent cation salt mixtures in contact with NaCl+CaCl_2 salt mixtures were studied at a total concentration of 0.05 M. The obtained results for polysulfone type membranes were compared with Neosepta CL-25T and CM2 cation exchange membranes.
Spectrophotometric Determination Of Cobalt, Nickel Palladium, Copper, Ruthenium And Molybdenum Using Sodium Isoamylxanthate In Presence Of Surfactants, Ashok Kumar Malik, K. N. Kaul, B. S. Lark, W. Faubel, A. L. J. Rao
Spectrophotometric Determination Of Cobalt, Nickel Palladium, Copper, Ruthenium And Molybdenum Using Sodium Isoamylxanthate In Presence Of Surfactants, Ashok Kumar Malik, K. N. Kaul, B. S. Lark, W. Faubel, A. L. J. Rao
Turkish Journal of Chemistry
A direct method has been developed for the spectrophotometric determination of microamounts of Co(II), Ni(II), Cu(II), Pd(II), Ru(III) and Mo(VI) using sodium isoamylxanthate as a reagent in the presence of surfactant as solubilising agent. The method has been applied to the determination of these metal ions in various alloys and in environmental samples (fly ash).
Unusual Chemical Constituents Of Lotus Garcinii (Fabaceae), Muhammad Shaiq Ali, Farman Ahmad, Viqar Uddin Ahmad, Iqbal Azhar, Khan Usmanghani
Unusual Chemical Constituents Of Lotus Garcinii (Fabaceae), Muhammad Shaiq Ali, Farman Ahmad, Viqar Uddin Ahmad, Iqbal Azhar, Khan Usmanghani
Turkish Journal of Chemistry
The methanol soluble part of Lotus garcinii, belonging to the family Fabaceae, yielded three new interesting metabolites: garceine (1), garoside (2) and garthiol (3), which have never been detected from any natural source. In addition, isophytol, hexadecanoic acid, cholesterol, oleanolic acid, butulinic acid and lupeol were also obtained for the first time from L. garcinii}. All the isolated metabolites were characterized by spectroscopic means.
Studies On The Thermal Decomposition Of Copper (Ii) Flouride Complexes With Various Amino Acids In Nitrogen Atmosphere, Muhammad Arif, Saeed-Ur Rehman, Muhammad Arshad, Khalid Masud, Nasima Arshad
Studies On The Thermal Decomposition Of Copper (Ii) Flouride Complexes With Various Amino Acids In Nitrogen Atmosphere, Muhammad Arif, Saeed-Ur Rehman, Muhammad Arshad, Khalid Masud, Nasima Arshad
Turkish Journal of Chemistry
Thermal decomposition reactions of various copper (II) fluoride complexes of the general type Cu (L) F.xH_2O (L= asparagine(asp), arginine (arg), methionine (meth) and proline (pro), x = 3 to 4) have been studied in nitrogen atmosphere using TG and DTA techniques. A possible mechanism of decomposition is suggested on the basis of the reactions of their pyrolysis. The residues obtained at the end of various decomposition processes were identified through IR spectrometry. The kinetic parameters such as energy of activation (E^o ) and order of reaction (n) were also determined.
The Isolation Of Carboxylic Acids From The Flowers Of Delphinium Formosum, Nedi̇me Dürüst, Seçki̇n Özden, Esra Umur, Yaşar Dürüst, Mustafa Küçüki̇slamoğlu
The Isolation Of Carboxylic Acids From The Flowers Of Delphinium Formosum, Nedi̇me Dürüst, Seçki̇n Özden, Esra Umur, Yaşar Dürüst, Mustafa Küçüki̇slamoğlu
Turkish Journal of Chemistry
From the flowers of Delphinium formosum Boiss. et Huet. (Ranunculaceae) trans-aconitic, p-hydroxybenzoic, p-coumaric, caffeic and chlorogenic acids were isolated and identified. In addition, protocatechuic, vanillic and gentisic acids were identified.
A Comparative Study On The Recovery Of Ecori Endonuclease From Two Different Genetically Modified Strains Of Escherichia Coli, Candan Tamerler, Zeynep İlsen Önsan, Betül Kirdar
A Comparative Study On The Recovery Of Ecori Endonuclease From Two Different Genetically Modified Strains Of Escherichia Coli, Candan Tamerler, Zeynep İlsen Önsan, Betül Kirdar
Turkish Journal of Chemistry
A laboratory scale procedure developed for the purification of EcoRI restriction endonuclease was applied to two different Escherichia coli} strains, E. coli 294 and E. coli M5248, which are genetically modified to overproduce the enzyme. The purification method consisted of three successive chromatographic steps including phosphocellulose and hydroxyapatite columns and further fractionation in a second phosphocellulose column. It was shown that the second phosphocellulose separation can be omitted in the case of E. coli 294. Quality control tests indicated enzyme preparations free of contaminants and endo- or exo-nucleases. The yields obtained at the final stage of the purification were 1.3x10^{5} …
Determination Of Fluoride And Some Metal Ion Levels In The Drinking Waters In Kayseri Province, Şeri̇fe Tokalioğlu, Uğur Şahi̇n, Şenol Kartal
Determination Of Fluoride And Some Metal Ion Levels In The Drinking Waters In Kayseri Province, Şeri̇fe Tokalioğlu, Uğur Şahi̇n, Şenol Kartal
Turkish Journal of Chemistry
Fluorine is one of the most common elements in the Earth's crust. Fluoride is recognized to be the most effective caries-preventive agent. The main sources of fluoride for people are generally food and drinking water. For this reason, the fluoride and also the metal ion (Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb and Zn) concentrations in the drinking waters collected from the city center of Kayseri and its counties were investigated. In the determination of fluoride and of Na and K, an ion-meter with a combination-fluoride electrode and a flame photometer were used, respectively. The levels of …
Cross-Correlation Noise Studies In Atomic Magnet-Optic Rotation Spectroscopy, Ahmet T. İnce
Cross-Correlation Noise Studies In Atomic Magnet-Optic Rotation Spectroscopy, Ahmet T. İnce
Turkish Journal of Chemistry
Analytical signals in an Atomic Magneto-Optic Rotation spectrometer are buried in noise at the limit of detection. The noisy analytical signals were analysed by carrying out mathematical correlation of their time domain waveforms. The noise components of signals were removed by auto-correlation to simplify the study. If noise interferes in analytical signals whose source is unclear, a cross-correlation of the output waveform with noise source may identify the source, e.g., mains frequencies and background radio signals. A cross-correlation will reveal whether the two signals are derived from the same source. This can also lead to an improvement in the signal …
Synthesis And Characterization Of Copper(Ii), Nickel(Ii), Cadmium(Ii), Cobalt(Ii) And Zinc(Ii) Complexes With 2-Benzoyl-3-Hydroxy-1-Naphthylamino-3-Phenyl-2-Propen-1-On, Mehmet Sönmez
Turkish Journal of Chemistry
Cu(II), Ni(II), Co(II), Zn(II) and Cd(II) complexes of 2-Benzoyl-3-hydroxy-1-naphthylamino-3-phenyl-2-propen-1-on, which is a derivative of carboxamide, were prepared and characterized by elemental, spectral and magnetic methods. Based on the analytical results, electronic and infrared spectral data and magnetic susceptibility measurements, suitable structures have been proposed. The formation of the complexes in solution was investigated conductometrically. 2-Benzoyl-3-hydroxy-1-naphthylamino-3-phenyl-2-propen-1-on was found to be a bidentate ligand coordinating through enolic oxygen and amide nitrogen. The complexes of Co(II) and Ni(II) are proposed to have an octahedral structure, while Cd(II), Cu(II) and Zn(II) are suggested to possess a square-planar environment in the complexes.
A Novel Technique For Silver Extraction From Silver Sulphide Ore, Sevda Ayata, Hüseyi̇n Yildiran
A Novel Technique For Silver Extraction From Silver Sulphide Ore, Sevda Ayata, Hüseyi̇n Yildiran
Turkish Journal of Chemistry
A novel technique for silver extraction from Ag_2S is described. The method utilizes thiosulphate as complexing reagent and the redox reaction between SO_2 added as Na_2SO_3 powder and H_2S gas evolved. The parameters of the reaction such as pH, the reaction temperature, the complex equilibrium of Ag^+ ion with thiosulphate and the solubility of Ag_2S were investigated. Silver ions, obtained by this means are collected in high purity (99%) by applying appropriate electrolysis conditions. The interference from other metallic impurities, namely copper, gold, iron and zinc, is eliminated by choosing an appropriate electrolysis potential.
Usefulness Of A Technique Based On Negative Corona Discharge For The Degradation Of Selected, Condensed Pahs: Application To The Oxidation Of Anthracene And Similar Structures, D. Tessi̇er, C. Oguic, J. Pinart, J. J. Aaron
Usefulness Of A Technique Based On Negative Corona Discharge For The Degradation Of Selected, Condensed Pahs: Application To The Oxidation Of Anthracene And Similar Structures, D. Tessi̇er, C. Oguic, J. Pinart, J. J. Aaron
Turkish Journal of Chemistry
The usefulness of negative corona discharge for oxidation of condensed polycyclic aromatic hydrocarbons (PAHs), including anthracene, naphthalene and 2,3-benzanthracene, adsorbed on a solid substrate is evaluated. In the case of anthracene, the application of corona discharge under high voltage (10-20 kV) for 10 to 180 min with a current intensity of 5-120 \mu A in a controlled, humid atmosphere leads to the progressive formation of anthraquinone. A kinetic study of the anthracene oxidation shows that the apparent half-lives range from 5 to 48 min, according to the initial anthracene amount (50-5000 nmol), indicating a reaction order between 0 and 1. …
Analysis Of Polychlorinated Dibenzofurans (Pcdfs) Isomers In Soil Samples, Mustafa Pehli̇van, Erol Pehli̇van
Analysis Of Polychlorinated Dibenzofurans (Pcdfs) Isomers In Soil Samples, Mustafa Pehli̇van, Erol Pehli̇van
Turkish Journal of Chemistry
This study presents an analytical method for the separation of a series of polychlorinated dibenzofurans (PCDFs) emitted to the soil. PCDF contaminants were concentrated from soil samples and isolated from other materials by chromatographic methods and their quantitative determinations were performed by GC/MS (gas chromatography/mass spectroscopy).
Photochemically-Induced Fluorescence Properties And Determination Of Flufenamic Acid, A Non-Steroidal Anti-Inflammatory Drug, In Urine And Pharmaceutical Preparation, Lei̇la Bettaieb, J. J. Aaron
Photochemically-Induced Fluorescence Properties And Determination Of Flufenamic Acid, A Non-Steroidal Anti-Inflammatory Drug, In Urine And Pharmaceutical Preparation, Lei̇la Bettaieb, J. J. Aaron
Turkish Journal of Chemistry
The photochemically-induced fluorescence (PIF) properties of flufenamic acid (FF), a non-steroidal anti-inflammatory drug (NSAID) were investigated in acidic (pH 1.0) aqueous solutions at room temperature. An optimization procedure, including the effects of UV irradiation time, pH and solvent, was established for the determination of FF. A linear logarithmic calibration plot was obtained over a wide concentration range of four orders of magnitude. A low limit of detection of 0.14 ng/mL was found. The relative standard deviation (RSD) was 6.6% . The PIF method was applied to the quantitative analysis of FF in urine and in a pharmaceutical preparation with satisfactory …
Accumulation Of Heavy Metals In Freshwater Organisms: Assessment Of Toxic Interactions, Neylan Di̇ri̇lgen
Accumulation Of Heavy Metals In Freshwater Organisms: Assessment Of Toxic Interactions, Neylan Di̇ri̇lgen
Turkish Journal of Chemistry
Heavy metals are continuously released into the terrestrial environment by natural sources and human activities. The uptake and accumulation of heavy metals by plants promotes a mechanistic understanding of the biological significance of particular metal concentrations and distributions in biota. The toxicity of chromium, zinc, copper and cobalt ions and their binary mixtures are studied at varying test levels using duckweed as the test organism. The accumulation of metal ions are determined by atomic absorption spectroscopy. The type of toxic interactions in binary mixtures is assessed as `synergistic', `antagonistic' and `additive' by a statistical approach.
Incorporation Of Edta For The Elimination Of Metal Inhibitory Effects In An Amperometric Biosensor Based On Mushroom Tissue Polyphenol Oxidase, Arzum Erdem, Di̇lşat Özkan, Burcu Meri̇ç, Kağan Kerman, Mehmet Özsöz
Incorporation Of Edta For The Elimination Of Metal Inhibitory Effects In An Amperometric Biosensor Based On Mushroom Tissue Polyphenol Oxidase, Arzum Erdem, Di̇lşat Özkan, Burcu Meri̇ç, Kağan Kerman, Mehmet Özsöz
Turkish Journal of Chemistry
Enzyme based biosensors are highly selective devices which rely on the specific binding of the target analyte (the substrate) to the active-site regions of the enzyme. The enzymatic reaction between mushroom tissue polyphenol oxidase and its substrate phenol is coupled with the use of potassium ferrocyanide (K_{4}Fe(CN)_{6}) as the mediator in ammonia buffer solution (pH 8.80). The response of devices is often affected by the presence of inhibitors, which combine with the free enzyme in a manner that prevents substrate binding. The objective of this study is to describe an efficient and yet simple strategy to eliminate the interference of …
The Composition Of Essential Oils From Two Varieties Of Sideritis Erythrantha Var. Erythrantha And Var. Cedretorum, Nurhayat Tabanca, Neş'E Kirimer, K. Hüsnü Can Başer
The Composition Of Essential Oils From Two Varieties Of Sideritis Erythrantha Var. Erythrantha And Var. Cedretorum, Nurhayat Tabanca, Neş'E Kirimer, K. Hüsnü Can Başer
Turkish Journal of Chemistry
Water distilled essential oils from two varieties of Sideritis erythrantha: var. erythrantha} and var. cedretorum, both endemic in Turkey, were analysed by GC/MS. The main components were characterized as \alpha -pinene (16.3-19.5%) and sabinene (6.1- 10.4%) for var. erythrantha; myrcene (21.9-24.3%) and \alpha -pinene (11.4- 12.4%) for var. cedretorum.
Optimization Of Process Parameters For Reactive Lactic Acid Extraction, Emi̇ne Kahya, Emi̇ne Bayraktar, Ülkü Mehmetoğlu
Optimization Of Process Parameters For Reactive Lactic Acid Extraction, Emi̇ne Kahya, Emi̇ne Bayraktar, Ülkü Mehmetoğlu
Turkish Journal of Chemistry
The reactive extraction method was used to separate lactic acid from its aqueous solutions. In this method, the amine in the solvent phase reacts with the lactic acid in the aqueous phase, resulting in the extraction of acid into the organic phase. In this study, Alamine 336 diluted with oleyl alcohol was used as the solvent. The effects of initial lactic acid concentration, pH, temperature, extraction time, stirring rate, the amount of Alamine 336 in oleyl alcohol and the ratio of organic phase volume to aqueous phase volume, V_{org}/V_{aq}, on the distribution coefficient of the lactic acid, K_D, were investigated. …
Investigation Of The Microporous And Mesoporous Structures Of The Reşadiye (Tokat/Turkey) Bentonite And Its Fractions, Müşerref Önal, Yüksel Sarikaya, Tülay Alemdaroğlu
Investigation Of The Microporous And Mesoporous Structures Of The Reşadiye (Tokat/Turkey) Bentonite And Its Fractions, Müşerref Önal, Yüksel Sarikaya, Tülay Alemdaroğlu
Turkish Journal of Chemistry
It was determined by X-ray diffraction that, besides containing clay minerals such as montmorillonite and illite, the original bentonite contained also clinoptilolite, opal-C, quartz, calcite and dolomite. The original bentonite was separated into four fractions by decantation and precipitation from its aqueous suspension. The adsorption and desorption of nitrogen on the original bentonite and its fractions at 77 K were investigated. The specific surface areas of the samples were determined according to the methods of Brunauer-Emmett-Teller, de Boer-Lippens, and Harkins-Jura by using the adsorption data. The mesopore size distribution curves were plotted by using the desorption data. The specific micropore …
Reaction Mechanism And Kinetics Of Aqueous Solutions Of 2-Amino -2 Methyl-1,3- Propanediol And Carbonyl Sulphide, Erdoğan Alper
Reaction Mechanism And Kinetics Of Aqueous Solutions Of 2-Amino -2 Methyl-1,3- Propanediol And Carbonyl Sulphide, Erdoğan Alper
Turkish Journal of Chemistry
The mechanism and kinetics of the reaction between aqueous solutions of COS and a sterically hindered primary amine, 2-amino-2-methyl-1,3-propanediol (AMPD), were investigated at 288-303 K using a stopped-flow technique. It was found that the reaction order according to power law kinetics was between 1.12 and 1.16 for an amine concentration range of 0.5 to 1.5 kmol m^{-3} . This overall order indicated that the thiocarbamate formation was complex and possibly involved a zwitterion intermediate. However, the experimental results can also be explained in terms of a single-step termolecular reaction mechanism. The kinetic rate parameters for aqueous AMPD solutions were obtained …
Modification Of Poly(Maleic Anhydride-Co-Styrene) With Hydroxyl Containing Compounds, Oya Gali̇oğlu Atici, Ahmet Akar, Roshan Rahimian
Modification Of Poly(Maleic Anhydride-Co-Styrene) With Hydroxyl Containing Compounds, Oya Gali̇oğlu Atici, Ahmet Akar, Roshan Rahimian
Turkish Journal of Chemistry
Soluble and cross-linked poly(maleic anhydride-co-styrene) copolymers were reacted with hydroxyl containing compounds such as salicylic acid, 2-phenyl ethanol, eugenol and paracetamole in acetone or dioxane solution at 50-80°C. The hydrolytic and controlled release behavior of the copolymers containing these compounds in water was studied. The extent of hydrolysis was found to be affected by the type of polymer support as well as time, temperature and the type of supported compound.
Determination Of Some Of The Physicochemical Properties Of Fine Alumina Powders Prepared By Emulsion Evaporation, Yüksel Sarikaya, İsmet Sevi̇nç, Müşerref Önal, Tülay Alemdaroğlu
Determination Of Some Of The Physicochemical Properties Of Fine Alumina Powders Prepared By Emulsion Evaporation, Yüksel Sarikaya, İsmet Sevi̇nç, Müşerref Önal, Tülay Alemdaroğlu
Turkish Journal of Chemistry
In order to prepare fine alumina powders, an emulsion was prepared under optimum conditions. The emulsion was examined by optical microscopy and the prepared fine alumina powders were characterised by electron microscopy. The particles were formed of porous spheres and their sizes were between 1 and 10 \\mum. The powder samples were sintered by varying the temperature between 700 and 1600°C. The adsorption and desorption of nitrogen on these samples were investigated. By using the adsorption data, the specific surface areas were calculated according to different procedures and the correlation between them was discussed. The specific micropore and mesopore volumes …
Copper Extraction From Aqueous Solution By Pentaerythrityl Tetrabenzylamine, Derya Kara, Mahi̇r Alkan, Ümi̇t Çakir
Copper Extraction From Aqueous Solution By Pentaerythrityl Tetrabenzylamine, Derya Kara, Mahi̇r Alkan, Ümi̇t Çakir
Turkish Journal of Chemistry
The extraction of copper(II) from the aqueous phase with pentaerythrityl tetrabenzylamine (PETBA), which was synthesized from pentaerythrityl tetrabromide and benzyl amine, was studied. The influences of ionic strength, extraction time, pH and temperature were evaluated. The extraction results showed that the ionic strength had no effect on extraction efficiency and that the extraction equilibrium was established in a few minutes. The extraction percentage was independent of pH up to pH 7.6 and then decreased gradually to zero at about pH 11.5. The stoichiometry of the compound formed was estimated to be Cu_2L(NO_3)_4, where L is PETBA. It was concluded that …
Investigations On The Electrochemical Surface Treatment Of Carbon Fibers, Erdal Bayramli, Levent Toppare, Naci̇ Kutay Eri̇nç
Investigations On The Electrochemical Surface Treatment Of Carbon Fibers, Erdal Bayramli, Levent Toppare, Naci̇ Kutay Eri̇nç
Turkish Journal of Chemistry
Desized polyacrylonitrile (PAN) based carbon fibers (CF) were chemically and electrochemically oxidized and reduced. CF surfaces were activated via cyclic voltammetry studies with anodic and cathodic scans. The changes in CF surfaces were studied by contact angle measurements. Lifshitz-van der Waals and acid-base components of single fibers were determined. In general, oxidation resulted in the formation of an acidic surface energy component and reduction gave rise to no change in the number of basic functionalities at the CF surface.
Secondary Amine Mediated Ring-Opening Of Tetrahydroimidazo[1,5- B ][1,2,4]Oxadiazol-2(1 H )-Ones, Necdet Coşkun
Secondary Amine Mediated Ring-Opening Of Tetrahydroimidazo[1,5- B ][1,2,4]Oxadiazol-2(1 H )-Ones, Necdet Coşkun
Turkish Journal of Chemistry
5,6,7,7a-Tetrahydroimidazo [1,5- b ][1,2,4]oxadiazol-2(1 H )-ones 1a-g converted to imidazoles in the presence of secondary amines. cis-Imidazooxadiazolones 1d-g gave the imidazoles 4d-g when treated with secondary amines, while the treatment of these compounds with tertiary amines afforded imidazoline 3-oxides 5d-g. In case of 1a-c, where R^1 is a hydrogen, tertiary amines induced elimination to give imidazoles 4a-c. In the case of 1a-c, probable trans elimination caused by triethylamine and pyridine and in the case of 1d-f, a concerted double cis elimination mediated by secondary amines is discussed.
Thermogravimetric Investigation Of The Dehydration Kinetics Of Ksf, K10 And Turkish Bentonite, Yalçin Tonbul, Kadi̇r Yurdakoç
Thermogravimetric Investigation Of The Dehydration Kinetics Of Ksf, K10 And Turkish Bentonite, Yalçin Tonbul, Kadi̇r Yurdakoç
Turkish Journal of Chemistry
The kinetic parameters for the dehydration of bentonite from Turkey, KSF and K10 were determined by using dynamic TG techniques. The Ozawa method is better for the dehydration of the clay samples than the first order equation of Coats and Redfern. The former function calculates consistently higher activation energies than the latter. The mean values of the activation energies in the \\alpha range 0.1-0.7, are 56-66 kJ mol^{-1} in the Ozawa method.