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Articles 9091 - 9120 of 10317
Full-Text Articles in Physical Sciences and Mathematics
Cadmium And Mercury Uptake By Immobilized Pleurotus Sapidus, Yağmur Yalçinkaya, M. Yakup Arica, Levent Soysal, Adi̇l Deni̇zli̇, Ömer Genç, Sema Bektaş
Cadmium And Mercury Uptake By Immobilized Pleurotus Sapidus, Yağmur Yalçinkaya, M. Yakup Arica, Levent Soysal, Adi̇l Deni̇zli̇, Ömer Genç, Sema Bektaş
Turkish Journal of Chemistry
Pleurotus sapidus} basidiospores immobilized onto Ca-alginate beads were used for the removal of cadmium and mercury ions from aqueous solutions. The biosorption of Cd(II) and Hg(II) ions on the alginate beads and both immobilized live and heat inactivated fungal mycelia of Pleurotus sapidus} was studied from aqueous solutions in the concentration range of 30-500 mg L^{ - 1}. The biosorption of Cd(II) and Hg(II) ions by the alginate and both live and heat inactivated immobilized preparations increased as the initial concentration of the ions increased in the medium. Maximum biosorption capacity for immobilized live and heat inactivated fungal mycelia of …
Phytochemical Studies At The Bulbs Of Ornithogalum Umbellatum L., Temi̇ne Şabudak, Ülkü Oyman
Phytochemical Studies At The Bulbs Of Ornithogalum Umbellatum L., Temi̇ne Şabudak, Ülkü Oyman
Turkish Journal of Chemistry
Phytochemical examination of the bulbs of Ornithogalum umbellatum L. led to the isolation a new steroidal compound. Its structure was determined to be 3-O-(2'-methoxy-4'-(2-pentenal))-phenyl sitosterol (1) by spectroscopic data and chemical evidence.
Terpenoids And Aromatic Compounds From Euphorbia Heteradena, Sevi̇l Öksüz, Ayhan Ulubelen, Asli Barla, Wolfgang Voelter
Terpenoids And Aromatic Compounds From Euphorbia Heteradena, Sevi̇l Öksüz, Ayhan Ulubelen, Asli Barla, Wolfgang Voelter
Turkish Journal of Chemistry
Euphorbia heteradena Jaub. & Spach (Euphorbiaceae), a plant endemic to Turkey, has not been investigated previously. The CH_{2}Cl_{2} extract of the aerial parts of Euphorbia heteradena yielded 24-methylenecycloartanol, cycloart-25-en-3\beta ,24-diol, cycloart-22-en-3\beta ,25-diol, vomifoliol, vomifoliol 9-O-\beta -D-glucopyranoside, 3,4,3'-tri-O-methoxy ellagic acid, syringic acid and scopoletin. The structures of the isolates were identified by high field spectroscopic methods including 1D and 2D NMR techniques.
Phenylethanoid Glycosides From Scutellaria Galericulata, Tayfun Ersöz, Deni̇z Taşdemi̇r, İhsan Çaliş, Chris M. Ireland
Phenylethanoid Glycosides From Scutellaria Galericulata, Tayfun Ersöz, Deni̇z Taşdemi̇r, İhsan Çaliş, Chris M. Ireland
Turkish Journal of Chemistry
From the aerial parts of Scutellaria galericulata L., four phenylethanoid glycosides, 2-(4-hydroxyphenyl)-ethyl-(6-O-caffeoyl)-\beta -D-glucopyranoside (1), calceolarioside B (2), osmanthuside E (3) and martynoside (4), were isolated. The structure elucidations of the isolated compounds were performed by spectroscopic (UV, IR, ESI-MS, 1D- and 2D-NMR) methods. Compounds 1-4 demonstrated scavenging properties toward the 1,1-diphenyl-1-picrylhydrazyl (DPPH) radical in TLC autographic assays.
Comparison Of Supercritical Fluid And Solvent Extraction Of Feverfew (Tanacetum Parthenium), Muammer Kaplan, Mark R. Simmonds, George Davidson
Comparison Of Supercritical Fluid And Solvent Extraction Of Feverfew (Tanacetum Parthenium), Muammer Kaplan, Mark R. Simmonds, George Davidson
Turkish Journal of Chemistry
High performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) analyses are used to show that supercritical fluid extraction (SFE) using carbon dioxide is an effective means of extracting a range of components from feverfew samples. It was found that the specific compositions of solvent extracts and SFE extracts are different. The amounts of the presumed active ingredient parthenolide have been confirmed to be very variable. Feverfew seeds were particularly rich in parthenolide, while dried powdered samples contained less and, in one case, none at all. The tunability of SFE has been demonstrated, and it was shown that successive extractions …
A Conformational Exploration Of Dissymmetric Macrolides Antibiotics, Salah Belaidi, A. Dibi, M. Omari
A Conformational Exploration Of Dissymmetric Macrolides Antibiotics, Salah Belaidi, A. Dibi, M. Omari
Turkish Journal of Chemistry
Conformational analysis of the macrolides from 12 to 22 links was carried out using molecular mechanics. Calculations indicate that each studied macrocycle presents eight families of preferential conformers. They result from the combination of the conformations of the two systems diene and \alpha ,\beta -unsaturated ester. Among these conformers three families (F5, F6 and F3) have the lowest energy. The two families F5 and F6 adopt an s-cis conformation of the ester function and s-trans of the diene system with a pseudo-parallel arrangement of the two systems for the first family and a pseudo-antiparallel for the second. The third family …
The Simultaneous Determination Of Quinoline Yellow (E-104) And Sunset Yellow (E-110) In Syrups And Tablets By Second Derivative Spectrophotometry, Mahmure Üstün Özgür, İkbal Koyuncu
The Simultaneous Determination Of Quinoline Yellow (E-104) And Sunset Yellow (E-110) In Syrups And Tablets By Second Derivative Spectrophotometry, Mahmure Üstün Özgür, İkbal Koyuncu
Turkish Journal of Chemistry
A very simple spectrophotometric method using measurements at zero-crossing wavelength is described for resolving binary mixtures of the food dyes, Sunset Yellow (E-110) and Quinoline Yellow (E-104). Calibration graphs are linear up to 15.0 \mu gml^{-1} of Sunset Yellow (r = 0.9998), and Quinoline Yellow (r = 0.9999). The assay procedure for E-110 and E-104 in pharmaceutical products involves the extraction of the dyes with AcOH/NaOAc buffer solution (pH = 4.5), filtration, and measurement of the second derivative absorbance values at 410.0 nm for E-104 and 533.1 nm for E-110. This method was used for determining synthetic mixtures of these …
Hplc Method For The Analysis Of Paracetamol, Caffeine And Dipyrone, M. Levent Altun
Hplc Method For The Analysis Of Paracetamol, Caffeine And Dipyrone, M. Levent Altun
Turkish Journal of Chemistry
An accurate, simple, reproducible and sensitive method for the determination of paracetamol, caffeine and dipyrone was developed and validated. Paracetamol, caffeine and dipyrone were separated using a \mu -Bondapack C _{8} column by isocratic elution with a flow rate of 1.0 ml/min. The mobile phase composition was 0.01 M KH_2PO_{4-} -methanol-acetonitrile-isopropyl alcohol (420: 20: 30: 30) (v/v/v/v) and spectrophotometric detection was carried out at 215 nm. The linear range of determination for paracetamol, caffeine and dipyrone were 0.409-400 \mu g/ml, 0.151-200 \mu g/ml and 0.233-600 \mu g/ml, respectively. The method was shown to be linear, reproducible, specific, sensitive and rugged.
Trypsin-Catalyzed Peptide Synthesis In Acetonitrile With Low Water Content, Yeşi̇m Yeşi̇loğlu, Ayten Sağiroğlu
Trypsin-Catalyzed Peptide Synthesis In Acetonitrile With Low Water Content, Yeşi̇m Yeşi̇loğlu, Ayten Sağiroğlu
Turkish Journal of Chemistry
Trypsin was immobilized to alumina by adsorption from its aqueous solutions. The activity of trypsin was increased by immobilization for peptide synthesis. With these immobilized enzymes Bz-Arg-Leu-NH_{2} dipeptide synthesis was carried out. Iso amylalcohol, tetrahydrofuran and acetonitrile were used as solvents giving the highest yield in the peptide formation reaction. The yield of the peptide was strongly dependent on water content in the reaction medium. The stability of alumina-immobilized trypsin is described.
Bromination Of 2,3-Dibromobenzobarrelene At Different Conditions: Highly Brominated Benzobicyclic Systems, Ari̇f Daştan
Bromination Of 2,3-Dibromobenzobarrelene At Different Conditions: Highly Brominated Benzobicyclic Systems, Ari̇f Daştan
Turkish Journal of Chemistry
The electrophilic addition of bromine to 2,3-dibromobenzobarrelene at 10^oC led to the formation of completely rearranged products in high yield. Bromination of 2,3-dibromobenzobarrelene with molecular bromine in decalin at 150^oC and with DBTCE in CCl_{4} at 77^oC gave rearranged and non-rearranged products. The radical and ionic mechanism are discussed. All compounds were characterized properly, by NMR spectroscopy and chemical transformation.
Synthesis Of New Substituted 6-(Morpholin-4-Yl)-1h-Benzimidazole Derivatives, Canan Kuş
Synthesis Of New Substituted 6-(Morpholin-4-Yl)-1h-Benzimidazole Derivatives, Canan Kuş
Turkish Journal of Chemistry
A series of various substituted benzimidazole derivatives containing fluoro and morpholino substituents at the 5 and 6 positions was synthesized and their structures were identified by spectroscopic techniques.
Synthesis And Magnetic, Spectral And Thermal Studies On Metal 1,3,8,10,15,17,22,24-Octanitrophthalocyanines, Kallam R. Venugopala Reddy, Jathi Keshavayya
Synthesis And Magnetic, Spectral And Thermal Studies On Metal 1,3,8,10,15,17,22,24-Octanitrophthalocyanines, Kallam R. Venugopala Reddy, Jathi Keshavayya
Turkish Journal of Chemistry
A simple and novel method for the preparation of 1,3,8,10,15,17,22,24-octanitrophthalocyanine derivatives, MPcON's (M = Fe (III)Cl, Zn(II), Co(II), Cu(II) and Ni(II)), was developed. The dark green complexes were characterized by elemental analysis, electronic spectra, IR spectra, thermogravimetry, differential thermal analysis, powder X-ray diffraction and magnetic susceptibility.
Phenolic Compounds From Scutellaria Pontica, Tayfun Ersöz, Ü. Şebnem Harput, İclal Saracoğlu, İhsan Çaliş, Yukio Ogihara
Phenolic Compounds From Scutellaria Pontica, Tayfun Ersöz, Ü. Şebnem Harput, İclal Saracoğlu, İhsan Çaliş, Yukio Ogihara
Turkish Journal of Chemistry
From the aerial parts of Scutellaria pontica, a phenolic glucoside, 3,5-dihydroxyphenyl \beta -D-glucopyranoside (1); as well as a C-glucosyl flavon, isovitexin (2); flavones and flavone glycosides, 5-hydroxy-7,3',4'-trimethoxyflavone (3); apigenin (4); apigenin-7-O-\beta-D-glucopyranoside (5); and apigenin-7-O-\beta-D-glucopyranoside-4'-O-methylether (6) were isolated in addition to two phenylethanoid glycosides, martynoside (7) and verbascoside (= acteoside) (8). The structures of the isolated compounds were established on the basis of spectroscopic evidence.
Solid-Phase Extraction Of Copper With Lead 4-Benzylpiperidinedithiocarbamate On Microcrystalline Naphthalene And Its Spectrophotometric Determination, Hasan Cesur, Beki̇r Bati
Solid-Phase Extraction Of Copper With Lead 4-Benzylpiperidinedithiocarbamate On Microcrystalline Naphthalene And Its Spectrophotometric Determination, Hasan Cesur, Beki̇r Bati
Turkish Journal of Chemistry
Using lead 4-benzylpiperidinedithiocarbamate complex (Pb(4-BPDC)_{2}), a solid-phase extraction method was developed for pre-concentration and spectrophotometric determination of copper in water samples. In this method, copper in large volume liquid phase quantitatively replaces lead on colorless Pb(4-BPDC)_{2} complex and naphthalene solid phase mixture forming Cu-4-benzylpiperidinedithiocarbamate complex (Cu(4-BPDC)_{2}). The solid phase containing colored Cu(4-BPDC)_{2} is dissolved in chloroform and its absorbance is measured at 437 nm against the reagent blank. The range of linearity is 0.4 -10 \mu gml^{-1} of copper in chloroform, the molar absorptivity of the complex determined from the linear portion of Beer's law plot is 8.197x10^{3} lmol^{-1}cm^{-1} and …
Thermal Behaviour Of Copper(Ii), Nickel(Ii), Cobalt(Ii) And Palladium(Ii) Complexes Of N,N-Dimethyl-N'-Benzoylthiourea, Göktürk Avşar, Nevzat Külcü, Hakan Arslan
Thermal Behaviour Of Copper(Ii), Nickel(Ii), Cobalt(Ii) And Palladium(Ii) Complexes Of N,N-Dimethyl-N'-Benzoylthiourea, Göktürk Avşar, Nevzat Külcü, Hakan Arslan
Turkish Journal of Chemistry
N,N-dimethyl-N'-benzoylthiourea (DMBT) complexes of Ni(II), Cu(II), Co(II) and Pd(II) were synthesised. The thermal decomposition of these metal complexes was investigated by TG, DTG and DTA. A GC-MS combined system was used to identify the products during pyrolytic decomposition. The pyrolytic end-products were identified by X-ray powder diffraction. The thermoanalytical data of these complexes are presented in this communication. The kinetic analysis of the thermogravimetric data was performed by using the Coats-Redfern and Horowitz-Metzger methods. All the metal complexes except Cu(II) complex undergo decomposition in three stages and NiS, CoS, Pd, and Cu remained as end-products of the complexes.
Electrochemical Behavior Of Benzo[C]Cinnoline And Its Bromo Derivatives, Ni̇lgün Seçken, M. Levent Aksu, Ali̇ Osman Solak, Emi̇ne Kiliç
Electrochemical Behavior Of Benzo[C]Cinnoline And Its Bromo Derivatives, Ni̇lgün Seçken, M. Levent Aksu, Ali̇ Osman Solak, Emi̇ne Kiliç
Turkish Journal of Chemistry
The electrochemical behavior of benzo[c]cinnoline and some of its bromo derivatives was studied. Two discrete 2-electron reduction waves in acidic and only one wave in basic media in ethyl alcohol-BR buffer system (l:5 v/v) were observed. A mechanism for the electrode reaction is proposed. Diffusion coefficients, formal potentials for and the derivatives, the number of electrons transferred were determined by using sampled current polarography, cyclic voltammetry, chronoamperometry, chronocoulometry and constant potential coulometry. Adsorption of the molecules on the surface of the mercury drop was analyzed and this phenomena was exploited to calculate the formal potentials and the diffusion coefficients of …
Molecular Dynamics Simulation Of Phase Transitions In Binary Lj Clusters, Adem Teki̇n, Mi̇ne Yurtsever
Molecular Dynamics Simulation Of Phase Transitions In Binary Lj Clusters, Adem Teki̇n, Mi̇ne Yurtsever
Turkish Journal of Chemistry
The structures of small clusters are studied extensively by classical simulation methods because of their interesting thermodynamic behavior. In this work, we study the thermodynamic properties of binary mixtures of noble gas atoms. Interatomic interactions are defined by 6-12 Lennard-Jones (LJ) potential. Starting from the global minimum of the potential energy surfaces, the systems are heated by increasing the total energy until melting occurs. The melting is observed by monitoring the Lindemann factor. The effects of the relative sizes of A and B atoms and the interaction strength of A-A, A-B, and B-B on the melting temperature of clusters containing …
The Second And Third Density Virial Coefficients Of Six Ar-Ne Mixtures At 25.0°C, Önder Korfali
The Second And Third Density Virial Coefficients Of Six Ar-Ne Mixtures At 25.0°C, Önder Korfali
Turkish Journal of Chemistry
In this paper we present a detailed experimental study of fractions, x_{Ar} = 0.0821, 0.2727, 0.3618, 0.5838, 0.7722 and 0.9049 at 25.0°C. The pressures are measured with a dead -- weight tester. The densities are determined from knowledge of the precise volume and weight measurement of the mixtures. Statistical analysis of the experimental data yielded very precise values for the second and third density virial coefficients. The second virial coefficients calculated with the least squares fitting method and corresponding to above argon mole fractions are 10^6B = 11.03, 9.16, 7.65, 1.83, -4.98 and --11.00 m^3mole^{-1}. Similarly the third virial coefficients …
The Use Of Chloranilic Acid For The Spectrophotometric Determination Of Three Antihistamines, Kanakapura Basavaiah, V. S. Charan
The Use Of Chloranilic Acid For The Spectrophotometric Determination Of Three Antihistamines, Kanakapura Basavaiah, V. S. Charan
Turkish Journal of Chemistry
Cyproheptadine hydrochloride (CPH), methdilazine hydrochloride (MDH) and promethazine theoclate (PMT) were determined in their pure state and in pharmaceutical formulations by a simple spectrophotometric method. The determination was based on the formation of a charge-transfer complex between chloranilic acid as a \pi-acceptor and the studied drugs as n-donors in an acetonitrile-chloroform mixture. The spectra, various experimental parameters, the stoichiometry and the stability of the complexes formed were investigated. The complexes formed were found to absorb at 520 nm. Beer's law is obeyed in the concentration ranges 25-125, 20-100 and 25-150 \mu g ml^{-1}, for CPH, MDH and PMT respectively. The …
Application Of Proton Conducting Polymer Electrolytes To Electrochromic Devices, Ayhan Bozkurt
Application Of Proton Conducting Polymer Electrolytes To Electrochromic Devices, Ayhan Bozkurt
Turkish Journal of Chemistry
Electrochromic display devices have been fabricated using Polydiallyldimethylammonium dihydrogenphosphate (PAMA^+ H_2PO_4^-) blended with H_3PO_4 as the electrolyte and WO_3 as the electrochromic film. The WO_3 deposited glass electrodes were doped with protons to form H_xWO_3 in which color depends on the charge density (CD) ranging from 0.01 to 0.04 C/cm^2. Proton conducting films of PAMA^+ H_2PO_4^- 2 H_3PO_4 (2 moles of acid per polymer repeat unit) were sandwiched between two electrodes to obtain the following symmetric configuration: Glass/ITO/WO_3/H^+ -electrolyte film/H_xWO_3 /ITO/Glass. Prior to construction of the electrochromic windows, the electrochemical stability of polymer/acid blends was determined via cyclic voltammetry (CV).
Determination Of Linear Alkylbenzene Sulphonates And Their Biodegradation Intermediates By Isocratic Rp-Hplc, Mehmet Akyüz, David J. Roberts
Determination Of Linear Alkylbenzene Sulphonates And Their Biodegradation Intermediates By Isocratic Rp-Hplc, Mehmet Akyüz, David J. Roberts
Turkish Journal of Chemistry
An HPLC method was developed to determine linear alkylbenzene sulphonates (LASs) and their biotransformation products sulphophenyl carboxylates by isocratic chromatography using two C_{18} columns in series. Solid-phase extraction with a (C_{18}) cartridge was employed to isolate LAS from sediment and sewage effluent samples. Sodium perchlorate and ammonium perchlorate were used as ion pair agents. The recovery of the compounds was 94% \pm 2 and 98% \pm 2 respectively for sediment and sewage effluent. It was demonstrated that it is possible to separate LAS compounds and their isomers and homologues using this system.
Determination Of Oxygen And Nitrogen Impurities In Magnesium Metal By Vacuum Distillation And Icp-Oes Techniques, Javed Akhtar, S. K. Durrani, N. A. Chughtai, M. Munir, Bashir Mohammad
Determination Of Oxygen And Nitrogen Impurities In Magnesium Metal By Vacuum Distillation And Icp-Oes Techniques, Javed Akhtar, S. K. Durrani, N. A. Chughtai, M. Munir, Bashir Mohammad
Turkish Journal of Chemistry
Due to the various promising properties of magnesium as a structural material and certain other applications such as a reducing agent for refractory metals, magnesium metal has great commercial importance in many technical industries but the presence of oxygen and nitrogen impurities adversely affects its physico-chemical and mechanical properties. Therefore, the exact measurement of oxygen and nitrogen impurities is essential. The accuracy of analytical values of micro amounts of nitrogen and oxygen (\mu g.g^{-1} level) in magnesium metal has been measured indirectly. The conditions for the vacuum distillation (VD) method were optimized. Analysis of residue for magnesium content was studied …
A Spectrophotometric Method For The Determination Of Prazosin Hydrochloride In Tablets, Mahmure Üstün Özgür, Sidika Sungur
A Spectrophotometric Method For The Determination Of Prazosin Hydrochloride In Tablets, Mahmure Üstün Özgür, Sidika Sungur
Turkish Journal of Chemistry
A rapid and sensitive analytical method was developed for the spectrophotometric assay of prazosin hydrochloride. The method is based on the formation of a coloured derivative between the drug and 1,2-naphthoquinone-4- sulphonic acid sodium salt (NQS). The reaction proceeds quantitatively at pH 4.5 and 70°C for 40 min. After the extraction of the derivative with chloroform: n-butanol (3:1), the absorbance was measured at 400 nm. The method was applied to commercially available tablets and the results were statistically compared with those obtained by ultraviolet spectrophotometric and differential pulse polarographic methods using t- and F-tests.
Determination Of Calcium, Magnesium And Aluminium In Magmatic Rocks After Ultrasonic Leaching By Flame Aas, M. Hi̇kmet Özkan, Mehmet Akçay
Determination Of Calcium, Magnesium And Aluminium In Magmatic Rocks After Ultrasonic Leaching By Flame Aas, M. Hi̇kmet Özkan, Mehmet Akçay
Turkish Journal of Chemistry
A method of ultrasonic leaching has been developed for the destructive analysis of magmatic rock samples^1. This method was applied to determine three new elements, Ca, Mg and Al, in magmatic rock samples. The accuracy of the ultrasonic leaching method (C_{ULM}) was tested using standard reference materials (SRMs) and the recovery ratio as K_1 = C_{ULM}/C_{SRM} was defined. Another recovery ratio, K_2, was also defined from the results of the conventional dissolution method (CDM), that is K_2 = C_{ULM}/C_{CDM}. The accuracy and precision of the method are comparable with those of conventional methods. The following recovery ratios were obtained for …
Electrodeposition Of Zinc From Chloride Solution, Yanjerappa Arthoba Naik, Thimmappa V. Venkatesha, Perdur Vasudeva Nayak
Electrodeposition Of Zinc From Chloride Solution, Yanjerappa Arthoba Naik, Thimmappa V. Venkatesha, Perdur Vasudeva Nayak
Turkish Journal of Chemistry
The electroplating of zinc is carried out in the presence of 3,4,5-Trimethoxy benzaldehyde from a chloride bath. The bath constituents are optimized through Hull cell experiments. Operating parameters such as pH, temperature, and current density are also optimized. The current efficiency and throwing power are measured at different current densities. Polarization study is carried out under galvanostatic conditions. Corrosion resistance test indicated good protection of steel by the coating. The consumption of brightener is determined in the laboratory scale. SEM photomicrographs revealed fine-grained structure of the deposit from the optimum bath. IR spectrum of the scratched deposit showed inclusion of …
Non-Covalent Immobilization Of Quince (Cydonia Oblonga) Polyphenol Oxidase, Hülya Yağar, Ayten Sağiroğlu
Non-Covalent Immobilization Of Quince (Cydonia Oblonga) Polyphenol Oxidase, Hülya Yağar, Ayten Sağiroğlu
Turkish Journal of Chemistry
A partially purified polyphenol oxidase from quince (Cydonia oblonga) was immobilized on bentonite by simple adsorption at pH 6.8. The properties of the immobilized enzyme were compared to those of the free enzyme. Optimum pH and temperature were determined to be 9.0 and 45°C, respectively, showing the alteration of pH and temperature profiles by immobilization. No drastic change was observed in the K_m value after immobilization. Catechol, L-DOPA, p-cresole and pyrogallol were tested as substrates. Thermal and storage stability and reusability experiments were carried out. It was observed that the immobilized enzyme had storage stability for a period of one …
Corrosion Of Reinforcing Steel In Concrete Immersed In Chloride Solution And The Effects Of Detergent Additions On Diffusion And Concrete Porosity, Hülya Kahyaoğlu, Mehmet Erbi̇l, Bi̇rgül Yazici, Ayşe Bahar Yilmaz
Corrosion Of Reinforcing Steel In Concrete Immersed In Chloride Solution And The Effects Of Detergent Additions On Diffusion And Concrete Porosity, Hülya Kahyaoğlu, Mehmet Erbi̇l, Bi̇rgül Yazici, Ayşe Bahar Yilmaz
Turkish Journal of Chemistry
In order to investigate the corrosion of reinforcing steel in concrete and the effects of chloride ions, oxygen diffusion and detergent additives of linear alkylbenzene (LAB) and linear alkylbenzene sulfonate (LAS), potentiokinetic experiments were carried out. Thus, by embedding steel electrodes into concrete specimens with a water/cement (W/C) ratio of 0.45, current-potential curves were obtained and the compressive strength of the specimens was measured. The electrochemical approach can be used to identify the effect of chloride on steel corrosion in concrete. It was found that the diffusion of chloride and oxygen through concrete and the reduction of oxygen on the …
Radio Frequency-Induced Plasma Polymerization Of Allyl Alcohol And 1-Propanol, Şennur Candan
Radio Frequency-Induced Plasma Polymerization Of Allyl Alcohol And 1-Propanol, Şennur Candan
Turkish Journal of Chemistry
The effect of the composite parameters' plasma power (P)-to-monomer flow rate (\phi) ratio (P/\phi) in the plasma polymerization of allyl alcohol and 1-propanol was studied. The radio-frequency plasmas of deposits operated at low power (1-15 W) were investigated using deposition rate measurements. Detailed chemical information on the plasma polymers was obtained by X-ray photoelectron spectroscopy (XPS). The study of the surface chemistry of films created from allyl alcohol and 1-propanol demonstrates the importance of the double bond for good \underline{C}-O group retention. The deposition rates of both plasma polymers were found to increase with increasing P. The comparison of the …
Bifunctional Allyl-Sulphonium Salt As A Novel Addition--Fragmentation Agent For Photoinitiated Cationic Polymerization, Utku Küçüktömbeki̇ci̇, Mustafa Deği̇rmenci̇, Yusuf Yağci
Bifunctional Allyl-Sulphonium Salt As A Novel Addition--Fragmentation Agent For Photoinitiated Cationic Polymerization, Utku Küçüktömbeki̇ci̇, Mustafa Deği̇rmenci̇, Yusuf Yağci
Turkish Journal of Chemistry
Bifunctional allyl tetrahydrothiophenium hexafluoroantimonate was synthesized via a one-pot reaction of 3-chloro-2-chloromethylpropene with thiophene in the presence of sodium hexafluoroantimonate. The initiation capability of this salt, in conjunction with a photochemical free radical source such as 2,2-dimethoxy-2-phenyl acetophenone and benzophenone, via an addition-fragmentation mechanism in the cationic polymerization of cyclohexene oxide and butyl vinyl ether is investigated.
Synthesis And Characterization Of Some 3-Alkyl-4-Amino-5-Cyanomethyl-4h-1,2,4-Triazoles, Nesli̇han Demi̇rbaş, Ahmet Demi̇rbaş, Kemal Sancak
Synthesis And Characterization Of Some 3-Alkyl-4-Amino-5-Cyanomethyl-4h-1,2,4-Triazoles, Nesli̇han Demi̇rbaş, Ahmet Demi̇rbaş, Kemal Sancak
Turkish Journal of Chemistry
The preparation and characterization of some 3-alkyl-4-amino-5-cyanomethyl-4H-1,2,4-triazoles with active methylene groups are described and their structural properties using NMR and IR spectra and elemental analyses are given.