Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Physics (455)
- Environmental Sciences (454)
- Computer Sciences (426)
- Chemistry (360)
- Mathematics (284)
-
- Life Sciences (257)
- Engineering (252)
- Earth Sciences (248)
- Education (215)
- Science and Mathematics Education (179)
- Social and Behavioral Sciences (149)
- Oceanography and Atmospheric Sciences and Meteorology (141)
- Arts and Humanities (118)
- Geology (105)
- Natural Resources and Conservation (93)
- Astrophysics and Astronomy (89)
- Physical Chemistry (86)
- Natural Resources Management and Policy (85)
- Water Resource Management (82)
- Teacher Education and Professional Development (79)
- Statistics and Probability (78)
- History (77)
- Higher Education (75)
- Materials Science and Engineering (69)
- History of Science, Technology, and Medicine (66)
- Applied Mathematics (64)
- Materials Chemistry (64)
- Mechanical Engineering (60)
- Environmental Health and Protection (58)
- Institution
-
- University of Nebraska - Lincoln (372)
- TÜBİTAK (220)
- Claremont Colleges (89)
- Air Force Institute of Technology (76)
- Chinese Chemical Society | Xiamen University (72)
-
- Utah State University (72)
- William & Mary (71)
- Missouri University of Science and Technology (66)
- Selected Works (64)
- Old Dominion University (60)
- Virginia Commonwealth University (58)
- Purdue University (47)
- Wright State University (46)
- University of Northern Iowa (44)
- Syracuse University (40)
- Dartmouth College (38)
- New Jersey Institute of Technology (38)
- Portland State University (38)
- University of New Hampshire (36)
- Chulalongkorn University (35)
- Singapore Management University (35)
- University of Kentucky (34)
- University of Colorado Law School (33)
- California Polytechnic State University, San Luis Obispo (31)
- Department of Primary Industries and Regional Development, Western Australia (28)
- University of Massachusetts Amherst (26)
- University of South Florida (25)
- Marquette University (24)
- Nova Southeastern University (24)
- Washington University in St. Louis (23)
- Keyword
-
- Nebraska (19)
- Test (13)
- Western Australia (13)
- Computer Science (12)
- Colorado (11)
-
- Hole (11)
- Logs (11)
- Mathematics (11)
- Utah (11)
- 04. Personalities in Polymer Science (10)
- Ecology (10)
- Environmental (10)
- Geochemistry (10)
- Newsletters (10)
- Pollutants (10)
- Polymer Science (10)
- United States (10)
- Virginia (10)
- Wyoming (10)
- College of Engineering and Computer Science (9)
- Endangered Species Act (9)
- Engineering (9)
- Groundwater (9)
- Management (9)
- Science news (9)
- Technical writing (9)
- Vegetation (9)
- Water (9)
- Galaxies: evolution (8)
- Impact (8)
- Publication
-
- Turkish Journal of Physics (112)
- Theses and Dissertations (81)
- Journal of Electrochemistry (72)
- Humanistic Mathematics Network Journal (65)
- Turkish Journal of Chemistry (54)
-
- Faculty Publications (53)
- Nebraska Tractor Tests (52)
- Journal of Mathematics and Science: Collaborative Explorations (49)
- Department of Computer Science Technical Reports (47)
- Turkish Journal of Mathematics (40)
- Dissertations, Theses, and Masters Projects (39)
- Bird Strike Committee-USA/Canada Joint Annual Meeting: 1st (1999) (37)
- Theses (36)
- Research Collection School Of Computing and Information Systems (35)
- Thai Environment (35)
- Journal of the Iowa Academy of Science: JIAS (34)
- Chemistry Faculty Research & Creative Works (33)
- Strategies in Western Water Law and Policy: Courts, Coercion and Collaboration (Summer Conference, June 8-11) (26)
- Reports (25)
- All Computer Science and Engineering Research (23)
- United States Department of Agriculture Wildlife Services: Staff Publications (23)
- Dartmouth Scholarship (21)
- Dissertations (21)
- All U.S. Government Documents (Utah Regional Depository) (20)
- Conservation and Survey Division (19)
- Physics Faculty Publications (19)
- Physics Faculty Research & Creative Works (19)
- All HMC Faculty Publications and Research (18)
- United States Geological Survey: Staff Publications (18)
- Bulletin of the Mineral Research and Exploration (17)
- Publication Type
- File Type
Articles 2191 - 2220 of 2555
Full-Text Articles in Physical Sciences and Mathematics
Stabilities Of Complexes Of Scandium(Iii) And Yttrium(Iii) With Catechol Derivatives, Naci̇ye Türkel, Rahmi̇ye Aydin, Ulvi̇ye Özer
Stabilities Of Complexes Of Scandium(Iii) And Yttrium(Iii) With Catechol Derivatives, Naci̇ye Türkel, Rahmi̇ye Aydin, Ulvi̇ye Özer
Turkish Journal of Chemistry
The interactions of scandium(III) and yttrium(III) ions with catechol derivatives; catechol(H_2L, CAT), 4-nitrocatechol(H_2L, 4NCAT) and 2,3-dihydroxynaphthalene- 6-sulphonic acid(H_2L, DHN) were investigated in different metal ion:ligand mole ratios, by potentiometry and spectrophotometry. The stoichiometries of formed complexes have been defined by Job's method and formation curves have been drawn for some complexes, whenever possible. The stability contants of the fourteen formed complexes in definite stoichiometries have been determined, in an ionic medium of 0.1M KNO_3 or NaClO_4 at a temperature of 25°C. Noticeably, complexes of scandium(III) ion formed at much lower pH values than complexes of yttrium(III) ion, and its catechol …
Synthesis, Characterization And In Vitro Degradation Of Poly(Dl-Lactide)/Poly(Dl-Lactide-Co-Glycolide) Films, Menemşe Gümüşdereli̇oğlu, Günday Deni̇z
Synthesis, Characterization And In Vitro Degradation Of Poly(Dl-Lactide)/Poly(Dl-Lactide-Co-Glycolide) Films, Menemşe Gümüşdereli̇oğlu, Günday Deni̇z
Turkish Journal of Chemistry
Poly(dl-lactide) (PLA) homopolymers and poly(dl-lactide-co-glycolide) (PLGA) copolymers were synthesized from their cyclic dimers, i.e. dl-lactide and glycolide, by ring-opening polymerization in the presence of catalyst stannous octoate and chain control agent lauryl alcohol. The effects of catalyst and chain control agent concentrations, reaction temperature, and reaction time on the molecular weight and yield of homopolymers were studied. The homopolymers were obtained in the intrinsic viscosity 0.1 to 1.0 dl/g range by changing the polymerization conditions. The copolymers in two different lactide/glycolide ratios, i.e. 90:10 and 70:30 and in 0.60 intrinsic viscosity were synthesized. The polymers were further characterized by IR, …
A Study Of The Thermodynamic Properties Of Poly [2-(3-Mesityl-3-Methylcyclobutyl)-2-Hydroxyethyl Methacrylate] At Infinite Dilution Using Inverse Gas Chromatography-2-Hydroxyethyl, İsmet Kaya, Kadi̇r Demi̇relli̇
A Study Of The Thermodynamic Properties Of Poly [2-(3-Mesityl-3-Methylcyclobutyl)-2-Hydroxyethyl Methacrylate] At Infinite Dilution Using Inverse Gas Chromatography-2-Hydroxyethyl, İsmet Kaya, Kadi̇r Demi̇relli̇
Turkish Journal of Chemistry
Some thermodynamic quantities were obtained for the interactions of poly [2-(3-mesityl-3-methylcyclobutyl)-2-hydroxyethyl methacrylate] with alcohols, ketones, acetates, aromatics and alkanes by inverse gas chromatography in the temperature range 160-200°C. The specific retention volumes, V°_g, weight fraction activity coefficients of solute probes at infinite dilution, \Omega^{\infty}_1, Flory-Huggins thermodynamic interaction parameters, \chi^{\infty}_{12} between polymer and solvents were determined. The partial molar free energy, \Delta \bar{G}^{\infty}_{1}, the partial molar heat of mixing, \Delta\bar{H}^{\infty}_1 at infinite dilution and the solubility parameters of the polymer, \delta_2 were calculated.
Some Chemical Constituents From Marine Algae Of Karachi Coast (Arabian Sea), Muhammad Shaiq Ali, Viqar Uddin Ahmad, Farah Mahzar, Iqbal Azhar, Khan Usmanghani
Some Chemical Constituents From Marine Algae Of Karachi Coast (Arabian Sea), Muhammad Shaiq Ali, Viqar Uddin Ahmad, Farah Mahzar, Iqbal Azhar, Khan Usmanghani
Turkish Journal of Chemistry
Some commonly available marine algae have been collected from the Karachi coast of Arabian Sea for the search of new chemical constituents having biological importance. The structures of purified samples have been elucidated with the aid of modern spectroscopic techniques. Among the known constituents a new metabolite (1) has been isolated from the brown alga Iyengaria stellata.
Adsorption Of Copper And Cadmium Lons By Activated Carbon From Rice Hulls, Murat Teker, Mustafa İmamoğlu, Ömer Saltabaş
Adsorption Of Copper And Cadmium Lons By Activated Carbon From Rice Hulls, Murat Teker, Mustafa İmamoğlu, Ömer Saltabaş
Turkish Journal of Chemistry
The removal of copper (II) and cadmium (II) ions from aqueous solutions, by adsorption on activated carbon prepared from rice hulls (ACRH), was investigated depending on pH, activated carbon dosage, contact time, initial metal concentration and solution temperature. The optimum values of pH, ACRH dosage and contact time were determined to be 5-8, 0.5 g ACRH/25 mL solution an 60 minutes respctively for the adsorption of Cu (II) ions and 5-8, 1.5 g ACRH/25 mL solution and 60 minutes for the adsorption of Cd (II) ions. From the initial concentrations, the constants for the Freundlich and Langmuir isotherm were calculated …
Investigation Of Adsorption Isotherms Of Myristic, Palmitic And Stearic Acids On Rice Hull Ash, Hüseyi̇n Topallar, Yüksel Bayrak
Investigation Of Adsorption Isotherms Of Myristic, Palmitic And Stearic Acids On Rice Hull Ash, Hüseyi̇n Topallar, Yüksel Bayrak
Turkish Journal of Chemistry
The adsorption of myristic, palmitic and stearic acids on rice hull ash from isooctane as solvent was studied and conformed to a Langmuir isotherm. Monolayer coverage was determined to be 40.08, 38.43 and 37.27 mg/g, respectively. The free energy of adsorption, \Delta G°_{ads}, for the adsorption was determined to be -6,25, -6.32 and -6.39 kcal mol^{-1} for the adsorbates, respectively. The equilibrium parameter indicated that rice hull ash is a good adsorbent for myristic, palmitic and stearic acids examined.
Determination Of Activation Energy For The Number Average Degree Of Polymerization Using The Fluorescence Method, Önder Pekcan, Yaşar Yilmaz
Determination Of Activation Energy For The Number Average Degree Of Polymerization Using The Fluorescence Method, Önder Pekcan, Yaşar Yilmaz
Turkish Journal of Chemistry
A novel method based on steady state fluorescence measurements is introduced for measuring the activation energy of the number average degree of polymerization (NADP). Pyrene (Py) was used as a fluorescence probe for real time monitoring of free-radical polymerization (FRP) of methyl methacrylate (MMA). In situ FRP experiments were performed at various temperatures. Positive activation energy for NADP was measured and found to be 9.2 kcal/mol.
Contamination Of Roadside Soil, Plants, And Air With Heavy Metals In Jordan, A Comparative Study, Quasem M. Jaradat, Kamal A. Momani
Contamination Of Roadside Soil, Plants, And Air With Heavy Metals In Jordan, A Comparative Study, Quasem M. Jaradat, Kamal A. Momani
Turkish Journal of Chemistry
Copper, lead, cadmium, and zinc levels were analyzed by atomic absorption spectrophotometry in surface soil, plants, and air samples taken from both sides of the major highway connecting Amman with the southern parts of Jordan. Elevated levels of the studied elements were found in both soil and plants on the east side and on the west side of the road compared with the background values. The higher levels of heavy metals east of the road were due to the westerly prevailing wind at the sampling sites. The comtamination decreased exponentially with distance from the edge of the road and dropped …
Determination Of Patent Blue V And Carmoisine In Gelatine Desserts By Derivative Spectrophotometry, Yüksel Özdemi̇r, Ayşe Arzu Akkan
Determination Of Patent Blue V And Carmoisine In Gelatine Desserts By Derivative Spectrophotometry, Yüksel Özdemi̇r, Ayşe Arzu Akkan
Turkish Journal of Chemistry
A first-derivative spectrophotometric method was developed for quantitative determination of two synthetic organic dyes, Carmoisine and Patent Blue V, which are under governmental regulations all over the world because of their toxicity and carcinogenity. In this study, Carmoisine and Patent Blue V were simultaneously determined in their binary mixtures by first-derivative spectrophotometry. The method was applied to different gelatine desserts. The first-derivative derivative method did not eliminate turbid background in the samples. A simple background correction procedure involving a C_{18}-cartridge sample preparation step was developed for determination of dyes in gelatine dessert by first-derivative spectrophotometry. The C_{18}-cartridge sample preparation step …
Chlorination Of Two Turkish Lignites In Water And Water-Carbon Tetrachloride Media, Semra Karaca, Yücel Yaşar Kadioğlu, Sami̇h Bayrakçeken, M. Şahi̇n Gülaboğlu
Chlorination Of Two Turkish Lignites In Water And Water-Carbon Tetrachloride Media, Semra Karaca, Yücel Yaşar Kadioğlu, Sami̇h Bayrakçeken, M. Şahi̇n Gülaboğlu
Turkish Journal of Chemistry
The chlorine uptake of two Turkish lignites during chlorinolysis with chlorine gas in water and water-carbon tetrachloride media at ambient pressure (\cong 610 mmHg) was examined. The effects of speed of stirring (5-20s^{-1}), particle size (74-88, 150-180 and 250-425 \mu m), temperature (13-70°C) and chlorination time (0-18000 s) were studied. It is shown that the amount of chlorine uptake of both coals increased with decreasing particle size and increasing temperature.
Stabilities Of Complexes Of Scandium(Iii) And Yttrium(Iii) With Salicylic Acid, Naci̇ye Türkel, Rahmi̇ye Aydin, Ulvi̇ye Özer
Stabilities Of Complexes Of Scandium(Iii) And Yttrium(Iii) With Salicylic Acid, Naci̇ye Türkel, Rahmi̇ye Aydin, Ulvi̇ye Özer
Turkish Journal of Chemistry
The interactions of Sc(III) and Y(III) ions with salicyclic acid, SA (H_2L), were studied in aqueous solution by means of potentiometric and spectroscopic methods. The binding of SA occurs in Y(III):SA system, either in (1:1) or (1:2) mole ratios. The stability constants of the mono protonated complex, YHL^{2+}, and Y(HL)_2^+ type complex were calculated. The coordination of Sc(III) to SA was defined by means of Job's plot and its formation curve. The stability constants of ScL^+ and Sc(HL)L type complexes were determined by analysis of the potentiometric data; the coordination of SA to Sc(III) occurred through carboxylate and phenolic oxygens. …
Conformational Analysis Of Linear Peptide (Glu^1-Leu^2-Leu^3-Gly^4-Gly^5-Arg^6-Phe^7nh_2 ), Lütfü Demi̇r, Abdulhali̇k Karabulut, Gökhan Budak, Yusuf Şahi̇n, Nagif Sefteroğlu
Conformational Analysis Of Linear Peptide (Glu^1-Leu^2-Leu^3-Gly^4-Gly^5-Arg^6-Phe^7nh_2 ), Lütfü Demi̇r, Abdulhali̇k Karabulut, Gökhan Budak, Yusuf Şahi̇n, Nagif Sefteroğlu
Turkish Journal of Chemistry
Conformational energy-minimization of the Sea Anemone and Sea Pansy neuropeptide Pol-RFamide (Glu^1-Leu^2-Leu^3-Gly^4-Gly^5-Arg^6-Phe^7-NH_2) was carried out by molecular mechanics (MM). The linkage bonds were characterized by the torsion angles \theta, \psi and \omega and the side groups were characterized by the torsion angles \chi_1, \chi_2, \chi_3\ldots The energy-map for each monopeptide of the Pol-RFamide I was drawn in the range of -180° to 180° with increments of 20°. Conformation facilities for monopeptides were determined from these maps. These results were used in the analysis of the dipeptide (Glu^1-Leu^2). Then, the (Glu^1-Leu^2-Leu^3) tripeptide was examined using the calculated results for the dipeptide. …
^1h Nmr Spectra Of Some Amidrazone Derivatives, Şule Bahçeci̇, Haydar Yüksek, A. Aykut İki̇zler
^1h Nmr Spectra Of Some Amidrazone Derivatives, Şule Bahçeci̇, Haydar Yüksek, A. Aykut İki̇zler
Turkish Journal of Chemistry
Fifteen amidrazone derivatives (six being new compounds) were synthesized and their proton magnetic resonance spectra were recorded in trifluoroacetic acid (TFA). The protonation shifts, related to alkyl groups and observed on comparison of the spectra run in a neutral solvent and TFA, were attributed to an amidinium-type resonance of the resulting cations in the acidic medium.
Thin Layer Chromatographic Separation And Quantitation Of L-Dopa And L-Tyrosine In Mixtures, Gülendem Günendi̇, Farünni̇sa Pamuk
Thin Layer Chromatographic Separation And Quantitation Of L-Dopa And L-Tyrosine In Mixtures, Gülendem Günendi̇, Farünni̇sa Pamuk
Turkish Journal of Chemistry
A new TLC separation and quantitation method for L-tyrosine and L-Dopa mixtures was developed. The minimum tyrosine and Dopa quantities which can be measured by this technique are 0.7 and 1.5 \mu g respectively. The method may be used to measure the kinetic parameters of polyphenoloxidase as well as to trace the enzyme catalyzed conversion of L-tyrosine into L-Dopa. For a set of 20 measurements the maximum difference between any two measurements of spot areas was found to be 3 mm^2 (4.5\%) for L-Dopa (4 \mu g) and 2mm^2 (5.6\%) for L-tyrosine (1\mu g).
Spectrophotometric Determination Of Uranium In Waste Water Of Phosphoric Acid And Fertilizer Manufacturing Process, Ahmet Uyanik, Ni̇hat Tinkiliç, M. Odabaşoğlu, Hüseyi̇n Karaca
Spectrophotometric Determination Of Uranium In Waste Water Of Phosphoric Acid And Fertilizer Manufacturing Process, Ahmet Uyanik, Ni̇hat Tinkiliç, M. Odabaşoğlu, Hüseyi̇n Karaca
Turkish Journal of Chemistry
In this study, waste water drains and produced phosphate fertilizers of conventional wet-process (hemihydrate) phosphoric acid and phosphate fertilizer plants were investigated to determine the average uranium contents in the active manufacturing period. The method chosen for the determination of uranium was an extension of an existing spectroanalytical method and was adopted for waste water analysis as described. The results show that average uranium contents (mg m^{-3}) in a three-month period are appreciable in the waste water channel of the H_3PO_4 unit, produce acid containing 28% P_2O_5 (20.75), H_3PO_4 unit, produce acid containing 54% P_2O_5 (35.69), NPK (Nitrogen, Phosphorus, Potassium …
Hydrogen Evolution At Platinum (Pt) And At Platinized Platinum (Ptz) Cathodes, Bi̇rgül Yazici
Hydrogen Evolution At Platinum (Pt) And At Platinized Platinum (Ptz) Cathodes, Bi̇rgül Yazici
Turkish Journal of Chemistry
In this study, the cathodic behaviours of bright platinum (Pt) and at platinized platinum (Ptz) on the platinum anode were investigated in a 1M Na_2SO_4 electrolyte (pH, from 2 to 8) by means of electrolysis. The theoretical (\Delta Erev) and experimental (\Delta E_{exp}) discharge potentials and the cathodic overpotentials (\etac) of the systems were determined. The amounts of hydrogen gas produced at different times on the cathodes at a constant potential (5V) were measured and the hydrogen yield was calculated. The resulting scheme has been very helpful to obtain wodified electrocatalytic coating and electrode structures at Ptz cathode, able to …
Reaction Mechanism And Kinetics Of Aqueous Solutions Of Primary And Secondary Alkanolamines And Carbon Dioxide, Olgac Bavbek, Erdoğan Alper
Reaction Mechanism And Kinetics Of Aqueous Solutions Of Primary And Secondary Alkanolamines And Carbon Dioxide, Olgac Bavbek, Erdoğan Alper
Turkish Journal of Chemistry
The mechanism and kinetics of the reaction between aqueous solutions of CO_2 and the alkanolamines 1-amino-2-propanol, 3-amino-1-propanol,2-methyl aminoethanol and 2-ethyl aminoethanol were investigated using a stopped flow technique. It was found that the reaction orders according to power law kinetics were between 1.1 and 2.0, depending on the alkanolamine and the concentration ranges investigated. This fractional order was therefore considered to be further evidence that carbamate formation takes place according to a zwitterion mechanism rather than a one-step reaction. The kinetic rate parameters for these alkanolamines were evaluated from experimental data at 303 K according to this mechanism.
Acidity Of Silica-Alumina Catalysts By Amine Titration Using Hammett Indicators And Ft-Ir Study Of Pyridine Adsorption, Mürüvvet Yurdakoç, Mehmet Akçay, Yalçin Tonbul, Kadi̇r Yurdakoç
Acidity Of Silica-Alumina Catalysts By Amine Titration Using Hammett Indicators And Ft-Ir Study Of Pyridine Adsorption, Mürüvvet Yurdakoç, Mehmet Akçay, Yalçin Tonbul, Kadi̇r Yurdakoç
Turkish Journal of Chemistry
In this study, characterization and surface acidity of Siral (SiO_2-Al_2O_3) compounds were investigated with Hammett acidity functions, the n-butylamine titration method and FTIR analysis of the spectra of pyridine adsorption. All the samples had an acid strength of H_0\leq+2.8. The calculated total amount of acid of the samples increased with the increase in SiO_2 content up to Siral 40 and then decreased sharply in the case of Siral 80. Maximum amount of acidity was observed in the case of Siral 40 as 1.37mmole/g. No evidence was found for a band at 1540 cm^{-1} on Pural indicating that there were no …
Chemical Investigation Of The Sponge Verongia Aerophoba, Zeynep Aydoğmuş, Nebi̇ye Ersoy, Sedat İmre
Chemical Investigation Of The Sponge Verongia Aerophoba, Zeynep Aydoğmuş, Nebi̇ye Ersoy, Sedat İmre
Turkish Journal of Chemistry
The solvent effect on Verongia aerophoba metabolites during the extraction and isolation processes were examined in this study. A major compound (6), a stereoisomer of fistularin-3, and a new compound (2) were isolated from the acetone extract of dried and ethanol extract of fresh V. aerophoba samples respectively. The structures of these metabolites were elucidated using spectroscopic methods.
Development Of Black Cobalt Selective Absorber On Copper For Solar Collectors, Fi̇gen Kadirgan, Mete Söhmen
Development Of Black Cobalt Selective Absorber On Copper For Solar Collectors, Fi̇gen Kadirgan, Mete Söhmen
Turkish Journal of Chemistry
An eletrolyte is proposed for the deposition of black cobalt selective absorber coating on copper plate. The influence of the electrolyte composition and operating parameters on the properties of black cobalt coatings including optical properties were studied. The optimum conditions to obtain a high absorptance/emittance ratio are described.
Comparative Mechanistic Studies On The Oxidation Of Aromatic And Aliphatic Hydroxyl Derivatives In An Alkaline Medium At Preanodized Pt, Au And Pt/Au Electrodes In Presence Of Redox Mediators, Sasha Kalcheva, Philip Iotov
Comparative Mechanistic Studies On The Oxidation Of Aromatic And Aliphatic Hydroxyl Derivatives In An Alkaline Medium At Preanodized Pt, Au And Pt/Au Electrodes In Presence Of Redox Mediators, Sasha Kalcheva, Philip Iotov
Turkish Journal of Chemistry
The role of redox mediators obtained from Pt, Au, and Pt/Au electrodes in the process of electrocatalytic oxidation of aromatic/aliphatic hydroxyl derivatives in an alkaline medium has been studied by applying cyclic voltammetry. Phenol and glycerol were used as aromatic and aliphatic hydroxyl derivatives in the electrochemical oxidation experiments. The results revealed that the presence of redox mediators formed by preliminary electrode anodization is crucial for the process of oxidation of aromatic compounds and imposes a different oxidation route for the aliphatic hydroxyl derivatives. The effect of preanodization has been related to the formation and dissolution of the corresponding higher …
Electrochemical Characterization Of Al_2 O_3 -Ni Thin Film Selective Surface On Aluminium, Fi̇gen Kadirgan, Ewa Wackelgard, Mete Söhmen
Electrochemical Characterization Of Al_2 O_3 -Ni Thin Film Selective Surface On Aluminium, Fi̇gen Kadirgan, Ewa Wackelgard, Mete Söhmen
Turkish Journal of Chemistry
Solar thermal collectors represent a widely used type of system for the conversion of solar energy. In order to produce selective coatings on aluminium substrates to be used as absorber plates in high efficiency solar collectors, nickel pigmentation was applied to anodically oxidised surfaces. Electrochemical dc methods are used to study the oxidation of aluminium as functions of the following electrolysis conditions: applied current, pH, temperature and concentration of electrolyte. The properties of the oxidised aluminium surfaces are investigated by cyclic voltammetry. Nickel pigmentation of porous aluminium surfaces was also performed as a function of electrochemical pigmentation conditions by ac …
The Effects Of Detergent Pollution On The Corrosion Of Iron And Aluminium, Si̇bel Zor, B. Yazici, M. Erbi̇l
The Effects Of Detergent Pollution On The Corrosion Of Iron And Aluminium, Si̇bel Zor, B. Yazici, M. Erbi̇l
Turkish Journal of Chemistry
The current-potential values were measured with iron or aluminium electrodes in solutions of 3.5% NaCl containing 30, 150, 300 ppm linear alkylbenzene (LAB) and detergents (LAS) at pH8. Polarization resistances (Rp) were determined using the values of current and potentials. The corrosion rates of iron and aluminium were determined in 2 and 4 hour intervals using the Mansfeld-Oldham equation based on the Stern-Geary and Butler-Volmer equations.
Reactions Of N-Aminopyrimidine Derivatives With 1,3-Dicarbonyl Compounds, Zülbi̇ye Önal, Behzat Altural
Reactions Of N-Aminopyrimidine Derivatives With 1,3-Dicarbonyl Compounds, Zülbi̇ye Önal, Behzat Altural
Turkish Journal of Chemistry
The reactions of 1-Amino-pyrimidine derivatives (1) and some 1,3-dicarbonyl compounds (2) were realized in the presence of p-toluensulfonic acid catalyst to give convenient enamine (3) and/or imine derivatives (4). In the same way, the enamine (5) and/or imine derivatives (6) were synthesized using (1) and 1,3-indanedione which is one of the different 1,3-dicarbonyl compounds. The molecular structures of all the prepared compounds were determined by ^1H-nmr, ^{13}C-nmr, i.r. spectra and elemental analyses, and were drawn by taking imine-enamine tautomerism into account.
A Modified Potentiometric Method For The Estimation Of Phenol In Aqueous Systems, Farhat Huma, Muhammad Jaffar, Khalid Masud
A Modified Potentiometric Method For The Estimation Of Phenol In Aqueous Systems, Farhat Huma, Muhammad Jaffar, Khalid Masud
Turkish Journal of Chemistry
A modified potentiometric titration is proposed for the estimation of phenol in aqueous systems. The method is evolved on the basis of a critical dependence of pH on log V rather than simple V, as used in conventional potentiometric titrations. The method incorporates titrants in a concentration range several orders of magnitude greater than that of phenol in the aqueous phase. Derivative potentiometric curves so obtained provide a clear exposition of the equivalence point and the overall error is found to be between \pm 1.0 and 1.5%. The range of phenol concentration investigated was from 10^{-2} to 10^{-3} M. and …
Electrochemical Behaviour Of Hexa[4-(Phenylazo) Phenoxy]Cyclotriphasphazene, Necati̇ Menek, Günseli̇ Turgut, Mustafa Odabaşioğlu
Electrochemical Behaviour Of Hexa[4-(Phenylazo) Phenoxy]Cyclotriphasphazene, Necati̇ Menek, Günseli̇ Turgut, Mustafa Odabaşioğlu
Turkish Journal of Chemistry
The polarographic and voltammetric behaviour of hexa[4-(phenylazo)phenoxy]cyclotriphasphazene in tetrahydrofuran-water 50% (v/v) was studied at room temperature using various electrochemical techniques. In this study, the reduction of the azo group to the amino group of the organophosphazenes compound was observed as the electrode reaction. An electrode reaction mechanism was suggested for the compound.
Synthesis, Structural And Thermal Studies Of Titanium(Iv) Complexes Of N-Alkyl Phenothiazines, Jaldappa Seetharamappa, Boregowda Keshavan
Synthesis, Structural And Thermal Studies Of Titanium(Iv) Complexes Of N-Alkyl Phenothiazines, Jaldappa Seetharamappa, Boregowda Keshavan
Turkish Journal of Chemistry
New coordination compounds of the type [Ti(C_2O_4)_2L]2H_2O where L=N-alkyl phenothiazines (NAPs) were synthesised and characterised by elemental analyses, molar conductance, magnetic, thermal and spectral data. The spectral data suggest the bidentate nature of NAPs in the complexes. An octahedral structure is proposed for all the complexes. Thermal studies were used to evaluate the kinetic and thermodynamic parameters.
Photometric Imaging Of Starspots, Techniques And Reliability, Zeki̇ Eker
Photometric Imaging Of Starspots, Techniques And Reliability, Zeki̇ Eker
Turkish Journal of Physics
Historical development of the starspot hypothesis and the unsolved problems associated with it are presented. The "non{uniqueness" attributed to the spot solutions is a major problem which could still discredit current efforts of starspot modeling by photometric or spectroscopic data. The basics of the starspot photometry(direct and inverse photometric problem, and the error analysis of the inverse problem) are presented. Since an analytical formulation exists to compute synthetic light curves from the physical parameters of spots, and recomputing original parameters analytically from the synthetic curves are also possible, the starspot hypothesis is a consistent physical problem. According to the error …
Ionizing Radiations And Annealing Influence On Mosfet Charge States, Zainabidinov Ciragiddin, Atamuratov Atabek, Ysupov Akhmed, Adinaev Kuvondik
Ionizing Radiations And Annealing Influence On Mosfet Charge States, Zainabidinov Ciragiddin, Atamuratov Atabek, Ysupov Akhmed, Adinaev Kuvondik
Turkish Journal of Physics
The threshold voltage shift \Delta V_T and its components due to trapped-oxide charges \Delta V_{Not} and Si-SiO_2 interface traps \Delta V_N in MOSFET exposed to Bremsstrahlung, Co_{60} irradiation and annealing were studied. Several effects caused by differences in the photon energies from two types of sources are discussed as well as a mechanism of changing the trapped-oxide and Si-SiO_2 interface traps by annealing. The mechanism is based on previously available models.
Electrons In Large-Bandgap Bulk Semiconductors And Quantum Wells, N. A. Zakhleniuk, M. Babiker, C. R. Bennett, B. K. Ridley
Electrons In Large-Bandgap Bulk Semiconductors And Quantum Wells, N. A. Zakhleniuk, M. Babiker, C. R. Bennett, B. K. Ridley
Turkish Journal of Physics
The analytical theory of hot electrons interacting with lattice vibrations, impurities, and interface roughness in quantum wells is developed. We have obtained new distribution functions which describe all the kinetic properties of the non-equilibrium electron gas. As a specific example we present the electric field dependence of the electron mobility in GaN-based quantum wells and in bulk GaN. The relative importance of the different scattering mechanisms is analysed in detail.