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Articles 6271 - 6300 of 10319
Full-Text Articles in Physical Sciences and Mathematics
Semi-Slant And Bi-Slant Submanifolds Of Almost Contact Metric 3-Structure Manifolds, Fereshteh Malek, Mohammad Bagher Kazemi Balgeshir
Semi-Slant And Bi-Slant Submanifolds Of Almost Contact Metric 3-Structure Manifolds, Fereshteh Malek, Mohammad Bagher Kazemi Balgeshir
Turkish Journal of Mathematics
In this paper we introduce the notions of semi-slant and bi-slant submanifolds of an almost contact 3-structure manifold. We give some examples and characterization theorems about these submanifolds. Moreover, the distributions of semi-slant submanifolds of 3-cosymplectic and 3-Sasakian manifolds are studied.
On Nearly Kenmotsu Manifolds, Behzad Najafi, Niloufar Hosseinpour Kashani
On Nearly Kenmotsu Manifolds, Behzad Najafi, Niloufar Hosseinpour Kashani
Turkish Journal of Mathematics
We prove that on a nearly Kenmotsu manifold a second-order symmetric closed recurrent tensor is a multiple of the associated metric tensor. We then find the necessary condition under which a vector field on a nearly Kenmotsu manifold will be a strict contact or Killing vector field. Finally, we prove that every \phi-recurrent nearly Kenmotsu manifold is an Einstein manifold and every locally \phi-recurrent nearly Kenmotsu manifold is a manifold of constant curvature -1 .
Some Results On Cyclic Codes Over The Ring R_{2,M}, Reza Sobhani, Maryam Molakarimi
Some Results On Cyclic Codes Over The Ring R_{2,M}, Reza Sobhani, Maryam Molakarimi
Turkish Journal of Mathematics
Let R_{k,m} be the ring F_{2^m}[u_1,u_2,...,u_k]/\gen u_i^2, u_iu_j-u_ju_i. In this paper, cyclic codes of arbitrary length n over the ring R_{2,m} are completely characterized in terms of unique generators and a way for determination of these generators is investigated. A F_{2^m}-basis for these codes is also derived from this representation. Moreover, it is proven that there exists a one-to-one correspondence between cyclic codes of length 2n, n odd, over the ring R_{k-1,m} and cyclic codes of length n over the ring R_{k,m}. By determining the complete structure of cyclic codes of length 2 over R_{2,m}, a mass formula for the …
Petrology, Geochemistry, And Evolution Of The Iron Skarns Along The Northern Contact Of The Eğrigöz Plutonic Complex, Western Anatolia, Turkey, Tolga Oyman, İsmet Özgenç, Murat Tokcaer, Mehmet Akbulut
Petrology, Geochemistry, And Evolution Of The Iron Skarns Along The Northern Contact Of The Eğrigöz Plutonic Complex, Western Anatolia, Turkey, Tolga Oyman, İsmet Özgenç, Murat Tokcaer, Mehmet Akbulut
Turkish Journal of Earth Sciences
The Çatak and Küreci skarn districts are located approximately 10 km NW of Emet (Kütahya) in Western Turkey. The skarn and associated ore formations mainly occur at the contact between intrusive rocks of the Eğrigöz Plutonic Complex (EPC) and calcareous pelitic schists with limestone lenses of the Sarıcasu Formation and meta-carbonate rocks of the Arıkaya Formation. The major, trace, and rare earth element analysis of the igneous rocks indicate that they are high level, subalkaline, calc-alkaline, peraluminous to metaluminous I-type intrusions, generated in a continental arc setting. Three distinct skarn-type mineralization, differing in their host rocks and distance from the …
Genesis Of Sedimentary- And Vein-Type Magnesite Deposits At Kop Mountain, Ne Turkey, Selahatti̇n Kadi̇r, Hasan Kolayli, Muhsi̇n Eren
Genesis Of Sedimentary- And Vein-Type Magnesite Deposits At Kop Mountain, Ne Turkey, Selahatti̇n Kadi̇r, Hasan Kolayli, Muhsi̇n Eren
Turkish Journal of Earth Sciences
Sedimentary- and vein-type magnesites were deposited within and on ultramafic rocks of the Kop Mountain region in Bayburt province. In the field, magnesites are exposed along NE-SW trending normal faults and in fractures in the ultramafic rocks. Petrographic studies reveal that magnesite is predominantly micrite, but also occurs as microsparite formed by recrystallization of micrite. The ultramafic rocks hosting the magnesites consist of serpentinized olivine, hypersthene and diopside. Ni, Co and Ti contents of magnesites suggest precipitation from percolating water through the serpentinized ultramafic rocks. The sedimentary- and vein-type magnesites have different \delta^{18}O and \delta^{13}C values, characterizing formation under different …
Controlling The Chaotic Discrete-Hénon System Using A Feedforward Neural Network With An Adaptive Learning Rate, Kürşad Gökce, Yilmaz Uyaroğlu
Controlling The Chaotic Discrete-Hénon System Using A Feedforward Neural Network With An Adaptive Learning Rate, Kürşad Gökce, Yilmaz Uyaroğlu
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes a feedforward neural network-based control scheme to control the chaotic trajectories of a discrete-Hénon map in order to stay within an acceptable distance from the stable fixed point. An adaptive learning back propagation algorithm with online training is employed to improve the effectiveness of the proposed method. The simulation study carried in the discrete-Hénon system verifies the validity of the proposed control system.
The Efficacy Of Travertine As A Palaeoenvironmental Indicator: Palaeomagnetic Study Of Neotectonic Examples From Denizli, Turkey, Beki̇r Levent Mesci̇, Orhan Tatar, John D. A. Piper, Hali̇l Gürsoy, Erhan Altunel, Stephen Crowley
The Efficacy Of Travertine As A Palaeoenvironmental Indicator: Palaeomagnetic Study Of Neotectonic Examples From Denizli, Turkey, Beki̇r Levent Mesci̇, Orhan Tatar, John D. A. Piper, Hali̇l Gürsoy, Erhan Altunel, Stephen Crowley
Turkish Journal of Earth Sciences
This study has aimed to evaluate whether a discernible environmental signature is recorded in tectonic travertine by applying palaeomagnetic study to examples from the Denizli region in western Turkey. Palaeomagnetic sampling in 7 quarry exposures through short stratigraphic intervals of bedded travertine has determined variations in magnetic susceptibility and palaeofield direction; the former is a potential proxy of climatically-controlled atmospheric dust input and the latter is a possible indicator of directional changes resulting from geomagnetic secular variation of the ancient magnetic field and hence a measure of the rate of travertine accretion. Most sites record normal polarity as predicted from …
Coeval Shoshonitic-Ultrapotassic Dyke Emplacements Within The Kestanbol Pluton, Ezine – Biga Peninsula (Nw Anatolia), Cüneyt Akal
Coeval Shoshonitic-Ultrapotassic Dyke Emplacements Within The Kestanbol Pluton, Ezine – Biga Peninsula (Nw Anatolia), Cüneyt Akal
Turkish Journal of Earth Sciences
The Biga Peninsula, in the north-western part of Western Anatolia, is part of the Sakarya Zone of the Western Pontides and the tectonically overlying Ezine group. The basement rocks are intruded by the early Miocene Kestanbol Pluton and early to middle Miocene calc-alkaline to shoshonitic-ultrapotassic volcanic successions related to postcollisional continental extension. The Kestanbol Pluton mainly comprises monzonite and granodiorite and is cut by shoshonitic-ultrapotassic tephriphonolite dykes. ^{40}Ar-^{39}Ar ages of biotite (21.22 ± 0.09 Ma) and leucite (22.21 ± 0.07 Ma) crystals indicate that tephriphonolite dyke emplacement was coeval with the intrusion of the Kestanbol Pluton during the early Miocene …
Oligocene Vegetation And Climate Characteristics In North-West Turkey: Data From The South-Western Part Of The Thrace Basin, Funda Akgün, Mehmet Serkan Akki̇raz, Sari̇ye Duygu Üçbaş, Mustafa Bozcu, Sevi̇nç Kapan, Ayşe Bozcu
Oligocene Vegetation And Climate Characteristics In North-West Turkey: Data From The South-Western Part Of The Thrace Basin, Funda Akgün, Mehmet Serkan Akki̇raz, Sari̇ye Duygu Üçbaş, Mustafa Bozcu, Sevi̇nç Kapan, Ayşe Bozcu
Turkish Journal of Earth Sciences
In this paper we present the first palynomorph and mollusc assemblages from the sediments in three different sections. From east to west, these are the Şevketiye (northern Biga Peninsula), the Tayfur (Gelibolu Peninsula) and the Kuzu harbour (Gökçeada) (parts of the Danişmen Formation) sections in the south and south-western side of the Thrace Basin (north-west Turkey), with the aim of obtaining information about the composition and structure of vegetation and climate during the Oligocene. The stratigraphic interval extends from late Rupelian to Chattian. The Danişmen Formation in the Şevketiye section yielded a palynomorph association with abundant coastal palms (Arecaceae; Lepidocaryoidae), …
Afc-Modeler: A Microsoft® Excel© Workbook Program For Modelling Assimilation Combined With Fractional Crystallization (Afc) Process In Magmatic Systems By Using Equations Of Depaolo (1981), Mehmet Keski̇n
Turkish Journal of Earth Sciences
AFC-Modeler is a user-friendly, interactive Microsoft Excel workbook program which is specifically designed to model up to ten theoretical AFC curves (corresponding to ten different r values; r being the ratio of mass assimilation rate to fractional crystallization rate) for a set of variables that can be interactively and precisely modified by the user (i.e. D, initial element concentration and isotope ratio in magma and element concentration and isotope ratio in wallrock). Being able to model ten curves for ten different 'r' values is an important feature of the program, because results of many studies indicate that the r values …
Tragulidae (Artiodactyla, Ruminantia) From The Middle Miocene Chinji Formation Of Pakistan, Muhammad Akbar Khan, Muhammad Akhtar
Tragulidae (Artiodactyla, Ruminantia) From The Middle Miocene Chinji Formation Of Pakistan, Muhammad Akbar Khan, Muhammad Akhtar
Turkish Journal of Earth Sciences
The fossil record of the Siwalik tragulids remains poorly documented. The study of the tragulid material from the Chinji Formation allows the identification of 3 species: Dorcatherium minus, Dorcatherium majus and Dorcabune anthracotherioides. The tragulid assemblage is quite rich and Dorcatherium is the predominant taxon in the Chinji Formation of Pakistan. The fossils from the Chinji Formation of the Chakwal district, northern Pakistan, may document the first appearance of the 3 tragulid species in the Lower Siwaliks. The selenodonty and palaeoecology of the Siwalik tragulids are also discussed.
Operational Characteristics Of A Filtering Rectifier Transformer For Industrial Power Systems, Zhiyu Zhao, Longfu Luo, Jiazhu Xu, Thanhngoc Tran, Zhiwen Zhang
Operational Characteristics Of A Filtering Rectifier Transformer For Industrial Power Systems, Zhiyu Zhao, Longfu Luo, Jiazhu Xu, Thanhngoc Tran, Zhiwen Zhang
Turkish Journal of Electrical Engineering and Computer Sciences
Many conventional methods focus on reducing the harmful impact of the poor power quality in industrial rectifier systems, but they focus more on the harmonic problems of the utility grid than they do on that of the rectifier transformer; hence, the rectifier transformer would still be adversely affected by harmonic pollution. In order to solve the problem, a filtering rectifier transformer is proposed that adopts a harmonic current drainage system that incorporates tertiary winding and tuned harmonic filters. The impedance of the tertiary winding is specially designed and the tuned harmonic filters work together to restrain the harmonic current and …
Central Anatolian Plateau, Turkey: Incision And Paleoaltimetry Recorded From Volcanic Rocks, Erkan Aydar, Hüseyi̇n Evren Çubukçu, Erdal Şen, Lütfi̇ye Akin
Central Anatolian Plateau, Turkey: Incision And Paleoaltimetry Recorded From Volcanic Rocks, Erkan Aydar, Hüseyi̇n Evren Çubukçu, Erdal Şen, Lütfi̇ye Akin
Turkish Journal of Earth Sciences
The erosion/incision patterns of radiometrically well-constrained volcanic rocks provide excellent markers for revealing the landscape evolution. The Central Anatolian High Plateau represents an uplifted area that reaches up to 1500 m above sea level and includes the Cappadocian Volcanic Province (CVP). The CVP is composed of horizontally emplaced Neogene-Quaternary ignimbrites intercalated with lava flows and epiclastic continental sediments. River incision rates have been calculated using the morphological/paleoaltimetric features of radiometrically well-constrained volcanic units in the area. Starting from 10 Ma until 5 Ma, there was no major erosion or incision. The morphology, uplift rate, and incision rates of the CVP …
Cenozoic Tectonics Of The Tuz Gölü Basin (Central Anatolian Plateau, Turkey), David Fernández-Blanco, Giovanni Bertotti, Tahsi̇n Atti̇la Çi̇ner
Cenozoic Tectonics Of The Tuz Gölü Basin (Central Anatolian Plateau, Turkey), David Fernández-Blanco, Giovanni Bertotti, Tahsi̇n Atti̇la Çi̇ner
Turkish Journal of Earth Sciences
We present a new 3D geologic model for the architecture and Cenozoic tectonic evolution of the Tuz Gölü Basin, a major sedimentary basin in the Central Anatolian orogenic plateau. This model is grounded on 7 depth-converted seismic reflection profiles in combination with the analysis of backstripped subsidence curves, isochore maps, and a palinspastically restored cross-section. Two stages of basin formation are detected during Cenozoic times. During the Palaeogene, around 2 km of basement subsidence led to the development of a sag basin broader than the present basin in the absence of bounding faults. After a period of uplift and erosion, …
Messinian Forced Regressions In The Adana Basin: A Near-Coincidence Of Tectonic And Eustatic Forcing, Ayhan Ilgar, Wojciech Nemec, Aynur Hakyemez, Erhan Karakuş
Messinian Forced Regressions In The Adana Basin: A Near-Coincidence Of Tectonic And Eustatic Forcing, Ayhan Ilgar, Wojciech Nemec, Aynur Hakyemez, Erhan Karakuş
Turkish Journal of Earth Sciences
This sedimentological and sequence-stratigraphic study focuses on the late Miocene deposits in one of the largest peri-Mediterranean basins of southern Turkey, the Adana Basin, which formed as a Tauride foreland depression accumulating molasse deposits. The Tortonian-Messinian shallow-marine Handere Formation, previously interpreted as a regressive succession, appears to have recorded several relative sea-level changes. The formation base recorded a forced regression attributed to the end-Serravalian (Tor-1) eustatic fall in sea level. The lower to middle part of the formation is transgressive, culminating in offshore mudstones. The upper part is regressive and its 3 isolated conglomeratic members represent sharp-based Gilbert-type deltas with …
Advances In The Chemistry Of Pyrazolopyrazoles, Rizk Elsyad Khidre, Hanan Ahmed Mohamed, Bakr Fathy Abdelwahab
Advances In The Chemistry Of Pyrazolopyrazoles, Rizk Elsyad Khidre, Hanan Ahmed Mohamed, Bakr Fathy Abdelwahab
Turkish Journal of Chemistry
Published data on the methods of preparation of pyrazolopyrazoles are summarized and described systematically. The title compounds are subdivided according to the position of fusion between the 2 pyrazole rings.
Fabrication Of Layer-By-Layer Deposited Films Containing Carbon Nanotubes And Poly(Malachite Green) As A Sensor For Simultaneous Determination Of Ascorbic Acid, Epinephrine, And Uric Acid, Jahan Bakhsh Raoof, Reza Ojani, Mehdi Baghayeri
Fabrication Of Layer-By-Layer Deposited Films Containing Carbon Nanotubes And Poly(Malachite Green) As A Sensor For Simultaneous Determination Of Ascorbic Acid, Epinephrine, And Uric Acid, Jahan Bakhsh Raoof, Reza Ojani, Mehdi Baghayeri
Turkish Journal of Chemistry
A simple approach to constructing a double-layer voltammetric sensor is described. The poly(malachite green) (PMG) and multiwalled carbon nanotubes (MWCNTs) were coimmobilized at the surface of the glassy carbon electrode (GCE) for fabrication of PMG/MWCNT/GCE. The modified electrode was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and chronoamperometric techniques. Using DPV, the obtained catalytic peak current was linearly dependent on the ascorbic acid (AA), epinephrine (EP), and uric acid (UA) concentrations in the ranges of 0.4-100.0, 0.1-100.0, and 0.3-90.0 \muM, respectively. The resultant detection limits for AA, EP, and UA were 0.23, 0.0820, and …
Mechanochemical Modification Method Used In The Development Of New Composite Materials Based On Epoxy Binder And Natural Minerals, Umida Ziyamukhamedova, Dilshod Djumabaev, Botirali Shaymardanov
Mechanochemical Modification Method Used In The Development Of New Composite Materials Based On Epoxy Binder And Natural Minerals, Umida Ziyamukhamedova, Dilshod Djumabaev, Botirali Shaymardanov
Turkish Journal of Chemistry
This article highlights the results of a mechanochemical modification method of epoxy composite materials and coatings on their base. It proves the mechanochemical activated components of composition to be the most acceptable for structuring when producing composite materials. It also states the increase of mechanical properties of epoxy heterocomposite coatings with mechanically activated particles by 25%-40%.
Disposable Carbon Electrodes As An Alternative For The Direct Voltammetric Determination Of Alkyl Phenols From Water Samples, Iulia Gabriela David, Irinel Adriana Badea, Gabriel Lucian Radu
Disposable Carbon Electrodes As An Alternative For The Direct Voltammetric Determination Of Alkyl Phenols From Water Samples, Iulia Gabriela David, Irinel Adriana Badea, Gabriel Lucian Radu
Turkish Journal of Chemistry
Disposable sensors based on a pencil graphite electrode were described for detection of alkyl phenols. The performances of the disposable bare pencil graphite electrode (PGE) and PGE modified with carbon nanotubes, regarding the cyclic and differential pulse voltammetric determination of 4-nonylphenol, 4-octylphenol, and 4-tert-octylphenol, were compared. Some experimental variables of the electrode surface pretreatment and measurement parameters were optimized. Using a phosphate buffer solution (pH 7.40) as the supporting electrolyte, alkyl phenols gave a well-defined oxidation peak at about 700 mV vs. Ag/AgCl. The detection limits established for each alkyl phenol were: 0.25 \muM for 4-octylphenol, 0.42 \muM for 4-nonylphenol, …
Synthesis, Characterization, And Swelling Behaviors Of A Ph-Responsive Cmc-G-Poly(Aa-Co-Amps) Superabsorbent Hydrogel, Yizhe Wang, Xiaoning Shi, Wenbo Wang, Aiqin Wang
Synthesis, Characterization, And Swelling Behaviors Of A Ph-Responsive Cmc-G-Poly(Aa-Co-Amps) Superabsorbent Hydrogel, Yizhe Wang, Xiaoning Shi, Wenbo Wang, Aiqin Wang
Turkish Journal of Chemistry
New superabsorbent hydrogels were synthesized through free radical graft copolymerization of partially neutralized acrylic acid (AA) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) onto carboxymethyl cellulose (CMC) backbones. The structure and morphology of the synthesized superabsorbent hydrogels were characterized by Fourier transform infrared spectroscopy and scanning electron microscope. The effect of the molar ratio of AMPS to AA, the APS concentration, and the CMC content on swelling ratio was optimized. The swelling properties in various pH solutions and saline solutions as well as the swelling kinetics were also evaluated. Results showed that the introduction of AMPS enhanced the swelling capacity, swelling rate, and …
Synthesis, Characterization, And Antimicrobial Activity Of Some New Phosphorus Macrocyclic Compounds Containing Pyrazole Rings, Tarik El-Sayed Ali, Salah Abdel-Aziz Abdel-Ghaffar, Kamilia Mohamed El-Mahdy, Somaia Mohamed Abdel-Karim
Synthesis, Characterization, And Antimicrobial Activity Of Some New Phosphorus Macrocyclic Compounds Containing Pyrazole Rings, Tarik El-Sayed Ali, Salah Abdel-Aziz Abdel-Ghaffar, Kamilia Mohamed El-Mahdy, Somaia Mohamed Abdel-Karim
Turkish Journal of Chemistry
A simple synthetic method is reported for the preparation of some new phosphorus macrocycles in which the pyrazole rings are appended to a phosphorus atom. The methodology is based on the cyclocondensation reaction of bis(4-formylpyrazolyl) phosphine oxide(1a, 1b) with nitrogen nucleophiles that contain active terminal amino groups. The antimicrobial activities of the synthesized compounds were assayed.
Ionic Liquid Mediated Synthesis, Reactions, And Insecticidal Activity Of 1-[(1h-Benzoimidazol-2-Yl)Amino]Spiro[Azetidine-4,4'-[4'H]Chroman]-2-Ones, Dr Kanti Sharma, Renuka Jain
Ionic Liquid Mediated Synthesis, Reactions, And Insecticidal Activity Of 1-[(1h-Benzoimidazol-2-Yl)Amino]Spiro[Azetidine-4,4'-[4'H]Chroman]-2-Ones, Dr Kanti Sharma, Renuka Jain
Turkish Journal of Chemistry
Ionic liquid mediated synthesis of novel heterocyclic compounds 1-[(1H-benzoimidazol-2-yl)amino]-2'-phenylspiro[azetidine- 4,4'-[4'H]chroman]-2-ones (3) and 1-[(1H-benzoimidazol-2-yl)amino]- 3-chloro-2'-phenylspiro[aze tidine-4,4'-[4'H] chroman]-2-ones (4) was accomplished by condensing substituted 2-hydrazino benzimidazole (1), flavanone (2), and acetyl chloride/chloroacetyl chloride in ionic liquid, [bmim]PF_6 with or without using catalyst in excellent yield (90%--95%). Further, compounds 3 and 4 were acylated with trifluoroacetic anhydride to give N-acylated products (5 and 10); 3 when treated with HCHO and (C_2H_5)_2NH gave Mannich bases (6) and with aldehydes afforded 3-arylidene-2-azetidinone (7). Compounds 4 underwent nucleophilic substitution with (i) KI (Finkelstein reaction) and (ii) phenols to give the corresponding iodo and phenoxy derivatives (8 …
Synthesis And Evaluation Of Acetylcholineesterase Inhibitory Potential And Antioxidant Activity Of Benzothiazine Derivatives, Durre Shahwar, Uzma Sana, Naeem Ahmad
Synthesis And Evaluation Of Acetylcholineesterase Inhibitory Potential And Antioxidant Activity Of Benzothiazine Derivatives, Durre Shahwar, Uzma Sana, Naeem Ahmad
Turkish Journal of Chemistry
The aim of the present study was to synthesize and characterize benzothiazine derivatives prepared by using 2-aminothiophenol and saccharine and in vitro screen their enzyme inhibition and antioxidant potential. Nine different derivatives were prepared and their structures were confirmed by spectral studies (EIMS, ^1 H and ^{13}C NMR). Enzyme inhibition potential of the synthesized compounds was evaluated by Ellman's method, while antioxidant activity was determined by DPPH and FRAP assays. All the derivatives showed remarkable activity against acetylcholine esterase with IC_{50} values in the range of 35.9--122.0 \mu M. All other derivatives, except compound 4a, were inactive towards DPPH radical. …
Synthesis And Antimicrobial Investigation Of Some 5h-Pyridazino[4,5-B]Indoles, İlker Avan, Alaetti̇n Güven, Kiymet Güven
Synthesis And Antimicrobial Investigation Of Some 5h-Pyridazino[4,5-B]Indoles, İlker Avan, Alaetti̇n Güven, Kiymet Güven
Turkish Journal of Chemistry
Synthesis and in vitro antimicrobial activities are reported for a series of 1,3,5-substituted 4-oxo-3,4-dihydro-5H-pyridazino[4,5-b]indole derivatives. Corresponding pyridazino[4,5-b]indoles were prepared from ethyl 3-formyl-1H-indole-2-carboxylate precursors and the functional group in question was installed with hydrazine and its derivatives. The purity and primary structures of pyridazino[4,5-b]indole were confirmed by IR, ^1 H NMR, and ^{13}C NMR spectroscopy and elemental analyses. All of the indoles were tested for in vitro antimicrobial activity against 8 isolates of bacteria and a fungus including Staphylococcus aureus NRRL B-767, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Proteus vulgaris NRRL-B123, Salmonella typhimurium NRRL B-4420, Bacillus subtilis NRRL 744, …
Application Of Experimental Design On Determination Of Aluminum Content In Saline Samples By Adsorptive Cathodic Stripping Voltammetry, Si̇nan Yilmaz, Betül Öztürk, Durmuş Özdemi̇r, Ahmet Emi̇n Eroğlu, Fatma Ni̇l Ertaş
Application Of Experimental Design On Determination Of Aluminum Content In Saline Samples By Adsorptive Cathodic Stripping Voltammetry, Si̇nan Yilmaz, Betül Öztürk, Durmuş Özdemi̇r, Ahmet Emi̇n Eroğlu, Fatma Ni̇l Ertaş
Turkish Journal of Chemistry
Adsorptive cathodic stripping voltammetric determination of aluminum at ng mL^{-1} levels in salt samples based on the metal complexation with Calcon (1-(2-hydroxynaphthylazo)-2 naphthol-4-sulfonic acid) and the subsequent adsorptive deposition onto a hanging mercury drop electrode was studied. Central composite design was used as a design method. Several chemical and instrumental parameters (pH, ligand concentration, deposition time, deposition potential, and complexing time) were involved in the experimental design. Analytical parameters such as repeatability, linearity, and accuracy were also investigated and the detection limit was found as 0.32 ng mL^{-1}.
Theoretical Study On The Addition Reaction Between Propadienylidene And Methyleneimine, Mengyuan Wang, Yungang Chen, Shanshan Ding, Yingde Wang, Qianchao Cao, Xiaojun Tan, Jinsong Gu
Theoretical Study On The Addition Reaction Between Propadienylidene And Methyleneimine, Mengyuan Wang, Yungang Chen, Shanshan Ding, Yingde Wang, Qianchao Cao, Xiaojun Tan, Jinsong Gu
Turkish Journal of Chemistry
The reaction mechanism between propadienylidene and methyleneimine was systematically investigated employing the second-order Møller--Plesset perturbation theory (MP2) method with the 6 -- 31 + G* basis set. Geometry optimization, vibrational analysis, and energy property of the involved stationary points on the potential energy surface were calculated. The energies of the different species were corrected by single point energy calculations at the CCSD (T) // MP2 / 6 -- 31 + G* level. From the surface energy profile, one important initial intermediate characterized by a 3-membered ring structure was located via a transition state firstly. After that, 3 different products possessing …
Terpenoids, Essential Oil Composition, Fatty Acid Profile, And Biological Activities Of Anatolian Salvia Fruticosa Mill., Gülaçti Topçu, Mehmet Öztürk, Tuba Kuşman, Ayşe Asli Barla Demi̇rkoz, Ufuk Kolak, Ayhan Ulubelen
Terpenoids, Essential Oil Composition, Fatty Acid Profile, And Biological Activities Of Anatolian Salvia Fruticosa Mill., Gülaçti Topçu, Mehmet Öztürk, Tuba Kuşman, Ayşe Asli Barla Demi̇rkoz, Ufuk Kolak, Ayhan Ulubelen
Turkish Journal of Chemistry
The hexane and dichloromethane extracts, obtained by re-extraction of the methanol extract of Salvia fruticosa Mill., afforded 7 diterpenoids (carnosol, carnosic acid, carnosic acid 12-methyl ether, rosmadial, isorosmanol, ferruginol, and manool), 4 triterpenoids (\alpha -amyryltetracosanoate, oleanolic acid, ursolic acid, and erythrodiol), a steroid (3-acetylsitosterol), and a flavone (salvigenin). The galls (apples) of the collected plant were separately extracted with hexane to afford fatty acids composed mainly of oleic acid (29\%), palmitoleic acid (29\%), and stearic acid (23.20\%), which exhibited high anticholinesterase activity, particularly against BChE. The essential oil, obtained from the aerial parts of the plant, exhibited high AChE inhibitory …
Poly(4-Vinylpyridine)-Supported Dual Acidic Ionic Liquid: An Environmentally Friendly Heterogeneous Catalyst For The One-Pot Synthesis Of 4,4'-(Arylmethylene)Bis(3-Methyl-1-Phenyl-1h-Pyrazol-5-Ols), Kaveh Parvanak Boroujeni, Pegah Shojaei
Poly(4-Vinylpyridine)-Supported Dual Acidic Ionic Liquid: An Environmentally Friendly Heterogeneous Catalyst For The One-Pot Synthesis Of 4,4'-(Arylmethylene)Bis(3-Methyl-1-Phenyl-1h-Pyrazol-5-Ols), Kaveh Parvanak Boroujeni, Pegah Shojaei
Turkish Journal of Chemistry
A poly(4-vinylpyridine)-supported Brønsted ionic liquid was easily prepared from its starting materials and used as a novel, highly efficient, and reusable heterogeneous catalytic system for the synthesis of 4,4'-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ols) from the condensation reaction between aromatic aldehydes and 2 equivalents of 3-methyl-l-phenyl-5-pyrazolone.
A Kinetic Study Of Atom Transfer Radical Polymerization Of Styrene With Bis(2-Pyridyl)Ethylenedimethanimine Derivative Ligands, Hülya Arslan, Yasemi̇n Küçük, Ayfer Menteş, Meti̇n Hayri̇ Acar
A Kinetic Study Of Atom Transfer Radical Polymerization Of Styrene With Bis(2-Pyridyl)Ethylenedimethanimine Derivative Ligands, Hülya Arslan, Yasemi̇n Küçük, Ayfer Menteş, Meti̇n Hayri̇ Acar
Turkish Journal of Chemistry
Atom transfer radical polymerization (ATRP) of styrene was carried out with multidentate nitrogen-based ligands, namely N,N'-bis[phenyl(pyrid-2-yl)methylene] ethane-1,2-diamine (BPDA) and N,N'-bis[methyl(pyrid-2-yl)methylene] ethane-1,2-diamine (BMDA), and catalyst systems at catalyst/ligand molar ratios of 1/0.33, 1/0.5, 1/1, and 1/1.5 by using 2 different initiators, (1-bromoethyl)benzene (BEB) and ethyl-2-bromopropionate (EBP). Linear first-order kinetic plots were observed for ATRP of styrene upon using BPDA as a ligand with both initiators. Even though the linear slopes indicate that radical concentration remains constant during reactions, high molecular weights were obtained at low conversion and showed a linear relation thereafter. To investigate the molecular weight effect, reactions were also …
A New Anthracene Derivative Of Calix[4]Arene As A Fluorescent Chemosensor, Özlem Şahi̇n, Mustafa Şahi̇n, Nuri̇ye Koçak, Mustafa Yilmaz
A New Anthracene Derivative Of Calix[4]Arene As A Fluorescent Chemosensor, Özlem Şahi̇n, Mustafa Şahi̇n, Nuri̇ye Koçak, Mustafa Yilmaz
Turkish Journal of Chemistry
A new anthracene derivative of calix[4]arene was synthesized as a highly fluorescent compound. This compound was examined for its fluorescent properties towards different metal ions (Li^+, Na^+, Mg^{2+}, Ca^{2+}, Ba^{2+}, Ni^{2+}, Cu^{2+}, Zn^{2+}, Pb^{2+}) by UV and fluorescence spectroscopy. On complexation by alkaline earth metal cations and transition metal cations, the fluorescence spectrum was quenched. In particular, Ca^{2+} caused greater than 98% quenching of the anthracene derivative of calix[4]arene.