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Articles 4021 - 4050 of 10319

Full-Text Articles in Physical Sciences and Mathematics

Determination Of Hydrogen Peroxide With An Enzymeless Amperometric Sensor Based On Poly(Vinylferrocene)-Supported Ag Nanoparticles, Mutlu Sönmez Çelebi̇, Kübra Öztürk, Mehmet Dumangöz, Fi̇li̇z Kuralay Jan 2018

Determination Of Hydrogen Peroxide With An Enzymeless Amperometric Sensor Based On Poly(Vinylferrocene)-Supported Ag Nanoparticles, Mutlu Sönmez Çelebi̇, Kübra Öztürk, Mehmet Dumangöz, Fi̇li̇z Kuralay

Turkish Journal of Chemistry

An enzymeless electrochemical sensor for detection of low amounts of H$_{2}$O$_{2}$ with the aid of Ag nanoparticles supported on conducting poly(vinylferrocene) (PVF) film was developed. Experimental results revealed that contribution of Ag nanoparticles led to remarkable improvement by means of reduction potential and reduction current. Influence of experimental parameters (i.e. polymeric film thickness, concentration of Ag precursor, immersion time in precursor solution, reduction time, and reduction potential) were investigated. The Ag/PVF-modified electrode system was characterized physically by scanning electron microscopy. The results revealed that the sensor developed was easy-to-prepare, economic, selective, and sensitive, with a fast response time of 3 …


Experimental And Theoretical Study Of Nh$_{3}$ Adsorption And Desorption Over A Cu-Chabazite Nh$_{3}$-Scr Catalyst, Selmi̇ Eri̇m Bozbağ, Mutlu Şi̇mşek, Onur Demi̇r, Deni̇z Şanli Yildiz, Hüseyi̇n Barkin Özener, Gökhan Hi̇sar, Can Erkey Jan 2018

Experimental And Theoretical Study Of Nh$_{3}$ Adsorption And Desorption Over A Cu-Chabazite Nh$_{3}$-Scr Catalyst, Selmi̇ Eri̇m Bozbağ, Mutlu Şi̇mşek, Onur Demi̇r, Deni̇z Şanli Yildiz, Hüseyi̇n Barkin Özener, Gökhan Hi̇sar, Can Erkey

Turkish Journal of Chemistry

NH$_{3}$ adsorption and desorption behavior of a commercial Cu-chabazite (CHA) NH$_{3}$ selective catalytic reduction (NH$_{3}$-SCR) catalyst was studied in the presence and absence of H$_{2}$O. NH$_{3}$ uptake values at various adsorption temperatures were obtained during various steps of the adsorption and temperature-programmed desorption (TPD) experiments. Total NH$_{3}$ uptake decreased from 4.6 to 1.6 g NH$_{3}$/L catalyst when the adsorption temperature was increased from 50 to 300 $^{\circ}$C. Three major adsorption sites for NH$_{3}$ adsorption could be identified and quantified using TPD experiments, namely loosely, moderately, and strongly bound NH$_{3}$ with peak centers at around 147, 266, and 447 $^{\circ}$C. The …


Hybrid Organic Molecules As Antiinammatory Agents; A Review Of Structuralfeatures And Biological Activity, Noor Ul Amin Mohsin, Matloob Ahmad Jan 2018

Hybrid Organic Molecules As Antiinammatory Agents; A Review Of Structuralfeatures And Biological Activity, Noor Ul Amin Mohsin, Matloob Ahmad

Turkish Journal of Chemistry

Nonsteroidal antiin ammatory drugs (NSAIDs) are widely used for the treatment of pain and in ammation. Some undesirable effects are linked with NSAIDs such as the gastrointestinal tract (GIT) toxicity and cardiovascular disturbances. At present the preparation of a hybrid molecular technique is being used to produce new analgesic and antiin ammatory molecules. Attachment of NSAIDs with nitric oxide and hydrogen sulfide releasing molecules produced some gastroprotective agents with improved analgesic and antiinflammatory activities. Combination of NSAIDs with different biologically active 5-membered, 6-membered, and condensed heterocyclic rings has also led to the formation of some potent molecules. Some of these …


Synthesis And Some Optical Results Of Long Chain Substituted Phthalocyanines, İbrahi̇m Özçeşmeci̇, İdri̇s Sorar Jan 2018

Synthesis And Some Optical Results Of Long Chain Substituted Phthalocyanines, İbrahi̇m Özçeşmeci̇, İdri̇s Sorar

Turkish Journal of Chemistry

Four metallo (zinc, copper, vanadyl, and indium) phthalocyanine derivatives bearing four aliphatic (hexylthio) groups were prepared from corresponding phthalonitrile compounds. The metallophthalocyanines were characterized with ultraviolet–visible spectroscopy (UV-Vis), proton nuclear magnetic resonance (1H NMR), Fourier transform-infrared spectroscopy (FT-IR), and mass and elemental analyses techniques. Aggregation properties of metallophthalocyanines in solution were studied in varied concentration ranges. Thin films of metallophthalocyanines were obtained by spin coating technique. Optical measurements showed that transmittance values of metallophthalocyanine thin films obviously changed with respect to the metal ion in the phthalocyanines. Transmittance spectra of the phthalocyanines synthesized using different metal ions showed a variation …


Facile Synthesis Of Heteroaryl Substituted -Lactams From Nitrovinyl Arenes, Seda Çinar, Canan Ünaleroğlu Jan 2018

Facile Synthesis Of Heteroaryl Substituted -Lactams From Nitrovinyl Arenes, Seda Çinar, Canan Ünaleroğlu

Turkish Journal of Chemistry

Aliphatic nitroalkanes with different functional groups were synthesized from the Michael addition reactions of active methylene compounds 2 and nitrovinyl arenes 1 in high yields. The synthesized Michael adducts were subjected to intramolecular cyclization to give heteroaryl substituted γ-lactams in good to high yields under mild reaction conditions.


Simultaneous Determination Of Azithromycin And Levooxacin In Pharmaceuticalsby Charge Transfer Complexation With Alizarin Red S Using An Absorption-Factormethod, Vijay D. Chavada, Nejal M. Bhatt, Mallika Sanyal, Pranav S. Shrivastav Jan 2018

Simultaneous Determination Of Azithromycin And Levooxacin In Pharmaceuticalsby Charge Transfer Complexation With Alizarin Red S Using An Absorption-Factormethod, Vijay D. Chavada, Nejal M. Bhatt, Mallika Sanyal, Pranav S. Shrivastav

Turkish Journal of Chemistry

A new approach based on a selective charge transfer reaction with alizarin red S is described for the simultaneous determination of azithromycin and levo oxacin in their binary mixtures using an absorption-factor spectrophotometric method. Native absorbance was used for the determination for levo oxacin, while a charge transfer complexation of alizarin red S served as the basis for the quantitation of azithromycin. The reaction of azithromycin with alizarin red S was possible in methanol under neutral conditions within 15 min at 25 ℃. The conditions were suitably optimized for selective complexation of azithromycin with minimal interference from levo oxacin. The …


Organic Modification Of Montmorillonite And Effect Of Catalytic Selectivity On Thedimerization Of Unsaturated Fatty Acid, Xue Huang, Guoqiang Yin, Guangzhu Feng Jan 2018

Organic Modification Of Montmorillonite And Effect Of Catalytic Selectivity On Thedimerization Of Unsaturated Fatty Acid, Xue Huang, Guoqiang Yin, Guangzhu Feng

Turkish Journal of Chemistry

This study describes the selective synthesis of C36-dimer fatty acids, by reacting unsaturated fatty acid at 533 K for 6 h in the presence of montmorillonite and lithium chloride as the catalyst and cocatalyst, respectively. The catalytic performance of different montmorillonite and organic modified montmorillonite catalysts was investigated in the dimerization of technical grade unsaturated fatty acid, and the influence of the catalyst structure and composition on the catalytic performance was analyzed. All the samples were characterized by X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscopy (TEM), thermogravimetry (TG), and dispersion experiments. The results …


One-Pot Synthesis Of New N-(1-Methylpyridin-4(1h)-Ylidene)Amine Ligands Forpalladium-Catalyzed Heck Coupling Reaction, Muhammad Zafar, Sabeen Zahra, Muhammad Tahir, Ehsan Mughal, Muhammad Nazar, Hummera Rafique Jan 2018

One-Pot Synthesis Of New N-(1-Methylpyridin-4(1h)-Ylidene)Amine Ligands Forpalladium-Catalyzed Heck Coupling Reaction, Muhammad Zafar, Sabeen Zahra, Muhammad Tahir, Ehsan Mughal, Muhammad Nazar, Hummera Rafique

Turkish Journal of Chemistry

A series of new derivatives of N-(1-methylpyridin-4(1H)-ylidene)amines, [L1]-[L5], were synthesized and characterized by FTIR, NMR, MS, and XRD analysis. These targeted compounds were synthesized by the melt reaction between N-methylated-4-chloropyridinium triflate and corresponding amines (1-naphthyl amine, o-ansidine, 2-nitroaniline, p-ansidine, and cyclohexyl amine) followed by the addition of sodium hydride in dichloromethane in the same pot. These highly electron-donating N-(1-methylpyridin-4(1H)-ylidene)amine ligands considerably improve the catalytic activity of palladium acetate towards Heck-Mizoroki carbon-carbon cross-coupling reactions.


Synthesis Of Benzaldehyde By Swern Oxidation Of Benzyl Alcohol In A Continuous Flow Microreactor System, Lin Zhu, Xiaohui Xu, Fuping Zheng Jan 2018

Synthesis Of Benzaldehyde By Swern Oxidation Of Benzyl Alcohol In A Continuous Flow Microreactor System, Lin Zhu, Xiaohui Xu, Fuping Zheng

Turkish Journal of Chemistry

Preparation of benzaldehyde by Swern oxidation of benzyl alcohol was carried out in a continuous flow microreactor system. Dimethyl sulfoxide (Me2SO) was used as oxidizing agent and oxalyl chloride or p-toluenesulfonyl (p-TsCl) chloride was used as the activating agent. Benzyl alcohol was oxidized to benzaldehyde by the Me2SO-activating agent mixture in the continuous flow microreactor system. The optimized reaction conditions of the Swern oxidation were as follows: oxalyl chloride was used as the activating agent; the mole ratio of Me2SO, oxalyl chloride, and benzyl alcohol was 4:2:1; the ow rate of Me2SO was 1.5 mL/min; the reaction temperature was 15 …


Adsorption Of Anionic And Cationic Dyes On Biochars, Produced By Hydrothermalcarbonization Of Waste Biomass: Effect Of Surface Functionalization And Ionicstrength, Ezgi̇ Çağlar, Yusuf Osman Donar, Ali̇ Sinağ, İbrahi̇m Bi̇roğul, Selva Bi̇lge, Kivanç Aydincak, Oleksii Pliekhov Jan 2018

Adsorption Of Anionic And Cationic Dyes On Biochars, Produced By Hydrothermalcarbonization Of Waste Biomass: Effect Of Surface Functionalization And Ionicstrength, Ezgi̇ Çağlar, Yusuf Osman Donar, Ali̇ Sinağ, İbrahi̇m Bi̇roğul, Selva Bi̇lge, Kivanç Aydincak, Oleksii Pliekhov

Turkish Journal of Chemistry

In this work, surface-functionalization agents and various salts as auxiliaries were used to improve the adsorption capacity of biochars produced via hydrothermal carbonization of glucose, cellulose, and hazelnut shell. The effect of surface functionalization with different acids and bases as well as neutral salts on the adsorption of methylene blue and methyl orange was investigated using Boehm titration, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy techniques. Surface functionalization of biochars leads to an increase in the number of oxygen-containing functional groups on the surface, thus increasing the adsorption capacity. To probe the influence of ionic strength on the adsorption …


Synthesis And Antioxidant, Aggregation, And Electronic Properties Of6-Tert-Butyl-1,4-Benzodioxine Substituted Phthalocyanines, Mehmet Sali̇h Ağirtaş, Beyza Cabi̇r, Selçuk Gümüş, Sadi̇n Özdemi̇r, Abdurrahman Dündar Jan 2018

Synthesis And Antioxidant, Aggregation, And Electronic Properties Of6-Tert-Butyl-1,4-Benzodioxine Substituted Phthalocyanines, Mehmet Sali̇h Ağirtaş, Beyza Cabi̇r, Selçuk Gümüş, Sadi̇n Özdemi̇r, Abdurrahman Dündar

Turkish Journal of Chemistry

As a starting material, 7-tert-butyldibenzo [b,e] [1,4] dioxine-2,3-dicarbonitrile was prepared by the reac- tion of 4-tert-butylcatechol with 4,5-dichlorophthalonitrile. Metallophthalocyanine complexes 4-7 were obtained by cyclotetramerization of 7-tert-butyldibenzo [b,e] [1,4] dioxine-2,3-dicarbonitrile. All compounds were characterized by elemental analysis and other spectroscopic methods (IR, UV/Vis, and $^{1}$H NMR). Phthalocyanine compounds remained nonaggregated in tetrahydrofuran at the studied concentration ranges. Metallophthalocyanines 4-7 were tested for their antioxidant activities. The antioxidant activity processes included evaluation of radical-scavenging activity, chelat- ing activity, and reducing power. These compounds were compared to standard antioxidant ascorbic acid. The electronic data of the new compounds were obtained by computational …


Gas Permeability Of Polydimethylsiloxane Membranes Lled With Clinoptilolite Indifferent Cationic Forms, Çi̇ğdem Atalay-Oral Jan 2018

Gas Permeability Of Polydimethylsiloxane Membranes Lled With Clinoptilolite Indifferent Cationic Forms, Çi̇ğdem Atalay-Oral

Turkish Journal of Chemistry

Zeolite-polymer mixed matrix membranes were prepared by lling polydimethylsiloxane (PDMS) with clinop- tilolite in various cationic forms of K, Mg, H, and Na. The membranes were characterized by scanning electron microscopy as well as measurements of O$_{2}, $N$_{2}$ and CO$_{2}$ gas permeabilities. The results indicated the presence of an optimum zeolite loading in the mixed matrix membranes maximizing permeability. The type of the cationic form of clinoptilolite used affected the permeabilities and ideal selectivities of the zeolite-polymer mixed matrix membranes investigated to some degree and some improvements were obtained when compared to the ideal selectivities of the original polymeric membranes.


Physicochemical Characterization Of A Polymeric Conductor: Application Todeuoridation Of Industrial Effluent By Electrodialysis, Maroua Arfaoui, Ali Ouejhani, Bechir Hamrouni Jan 2018

Physicochemical Characterization Of A Polymeric Conductor: Application Todeuoridation Of Industrial Effluent By Electrodialysis, Maroua Arfaoui, Ali Ouejhani, Bechir Hamrouni

Turkish Journal of Chemistry

In many places around the world, the uoride concentration in ground water as raw water is higher than the threshold standard for healthy drinking water. The aim of this work is to study the characteristics of an anionic membrane that will be the subject of an application for de uoridation by electrodialysis. The first objective of this work is to evaluate the physicochemical characteristics of the membrane used in experiments by determination of the exchange capacity, water uptake, ionic conductivity, and transport number (Hittorf method). The second part consists of studying the effect of different parameters such as electrodialysis time, …


Nanocapsulation Of Herbicide Haloxyfop-R-Methyl In Poly(Methyl Methacrylate):Phytotoxicological Effects Of Pure Herbicide And Its Nanocapsulated Form Onduckweed As A Model Macrophyte, Samaneh Torbati, Mehdi Mahmoudian, Neda Alimirzaei Jan 2018

Nanocapsulation Of Herbicide Haloxyfop-R-Methyl In Poly(Methyl Methacrylate):Phytotoxicological Effects Of Pure Herbicide And Its Nanocapsulated Form Onduckweed As A Model Macrophyte, Samaneh Torbati, Mehdi Mahmoudian, Neda Alimirzaei

Turkish Journal of Chemistry

In the present study the nanocapsulation of Haloxyfop-R-methyl in poly(methyl methacrylate) was success- fully performed. Poly(methyl methacrylate)/Haloxyfop-R-methyl nanocapsules were synthesized using a miniemulsion method and their surface morphology was studied by scanning electron microscopy and transition electron microscopy. The chemical characterization of nanocapsules was done by FT-IR spectroscopy. The herbicide loading and encap- sulation efficiency were also analyzed for the herbicide-loaded nanocapsules. In order to evaluate the toxic effects of nanocapsulated herbicide and pure herbicide on Lemna minor L., some physiological effects of these two compounds were investigated. The plant growth rate, photosynthetic pigment contents, and activities of antioxidant enzymes …


Geochemical, Microthermometric, And Isotopic Constraints On The Origin Of Fluorite Deposits In Central Anatolia, Turkey, Peli̇n Coşanay, Ece Kirat, Ni̇hal Çevi̇k, Ceyda Kizilkanat, Hali̇m Mutlu, Şükrü Koç Jan 2017

Geochemical, Microthermometric, And Isotopic Constraints On The Origin Of Fluorite Deposits In Central Anatolia, Turkey, Peli̇n Coşanay, Ece Kirat, Ni̇hal Çevi̇k, Ceyda Kizilkanat, Hali̇m Mutlu, Şükrü Koç

Turkish Journal of Earth Sciences

We investigate rare earth element geochemistry, microthermometric characteristics, and radiogenic isotope systematics of fluorites and stable isotope compositions of gangue minerals from several fluorite deposits in central Turkey. In the deposits, fluorite is the main ore mineral and it is accompanied by quartz, calcite, and minor pyrite and barite. Veins are represented by three different fluorite types based on their color. Total REY contents of fluorites are highly variable, ranging from 24 to 693 ppm. LREE concentrations of fluorites of all colors are similar but medium and heavy REE abundances of green fluorites are nearly an order of magnitude greater …


Paleoenvironment Of The Late Oligocene From The Kağızman-Tuzluca Basin (Northeastern Anatolia) Based On The Micro- And Macrofloras, Mi̇ne Sezgül Kayseri̇ Özer, Recep Hayretti̇n Sancay, Şevket Şen, Koray Sözeri̇, Gregoire Métais, Turhan Ayyildiz, Baki̇ Erdoğan Varol Jan 2017

Paleoenvironment Of The Late Oligocene From The Kağızman-Tuzluca Basin (Northeastern Anatolia) Based On The Micro- And Macrofloras, Mi̇ne Sezgül Kayseri̇ Özer, Recep Hayretti̇n Sancay, Şevket Şen, Koray Sözeri̇, Gregoire Métais, Turhan Ayyildiz, Baki̇ Erdoğan Varol

Turkish Journal of Earth Sciences

The Kağızman-Tuzluca Basin in East Anatolia is still poorly documented for its stratigraphy and in particular its paleofloral assemblages. In this study, the microfloras from the Kağızman-Kötek and Kömürlü areas and the macroflora from the Tuzluca area in this basin have been defined to overcome this deficiency. Sedimentary sequences of the Kağızman-Kömürlü area have been deposited in terrestrial conditions different from the sequences of the Kağızman-Kötek and Tuzluca areas, which were deposited in brackish conditions near a shallow marine environment. Paleovegetation in eastern Anatolia is represented by mixed mesophytic and coniferous forests restricted to high and middle altitudes (e.g. Pinus, …


The Discovery Of A Low-Angle Normal Fault In The Taurus Mountains: The İvriz Detachment And Implications Concerning The Cenozoic Geology Of Southern Turkey, Gürol Seyi̇toğlu, Veysel Işik, Esra Gürbüz, Alper Gürbüz Jan 2017

The Discovery Of A Low-Angle Normal Fault In The Taurus Mountains: The İvriz Detachment And Implications Concerning The Cenozoic Geology Of Southern Turkey, Gürol Seyi̇toğlu, Veysel Işik, Esra Gürbüz, Alper Gürbüz

Turkish Journal of Earth Sciences

The İvriz detachment fault has been determined on the southern border of the Ulukışla basin separating the metamorphic Bolkar Group of the Taurus Mountains and the Paleocene-Lower Eocene Halkapınar formation of basin deposits. The fault dips towards the north and has kinematic indicators (asymmetric grain/grain aggregate porphyroclasts, oblique foliation, and S-C fabrics), suggesting a top-to-the-N-NE sense of shearing. The clastic material originating from the Bolkar Group in the sedimentary units of the Ulukışla basin demonstrates that the detachment fault could have been be active during Latest Cretaceous-Eocene times. The İvriz detachment may have initiated as part of a high-angle breakaway …


The Impact Of Eustasy, Tectonics, And Paleoclimate On The Dolomitization Of The Syn-Rift Neogene Carbonate Platforms In The Red Sea Coastal Area, Egypt, Abdallah Mohammed Hassan Jan 2017

The Impact Of Eustasy, Tectonics, And Paleoclimate On The Dolomitization Of The Syn-Rift Neogene Carbonate Platforms In The Red Sea Coastal Area, Egypt, Abdallah Mohammed Hassan

Turkish Journal of Earth Sciences

A very significant quantity of dolomites and dolomitic limestones of variable origins occurs in the syn-rift Neogene carbonate platforms of the NW Red Sea coast and the Gulf of Suez. These are more common in the Um Diheisi Member of the Ranga Formation (early Miocene), the Um Mahara Formation (middle Miocene), the Um Gheig Formation (late Miocene), and the Dashet El Dabaa Member of the Shagra Formation (Pliocene). Based on their stratigraphic distribution, petrography, and cathodoluminescent characteristics, as supported by geochemical data, syn-rift irregular morphotectonic relief, and the eustasy, four distinct types of dolomites have been identified and were interpreted …


Crustal S-Wave Structure Around The Lake Van Region (Eastern Turkey) From Interstation Rayleigh Wave Phase Velocity Analyses, Hakan Çinar, Hamdi̇ Alkan Jan 2017

Crustal S-Wave Structure Around The Lake Van Region (Eastern Turkey) From Interstation Rayleigh Wave Phase Velocity Analyses, Hakan Çinar, Hamdi̇ Alkan

Turkish Journal of Earth Sciences

This study focuses on the average crustal and the upper mantle structure throughout the Lake Van region of eastern Turkey. The study aimed to investigate the structure with the fundamental mode interstation Rayleigh wave phase velocities from the local and the regional earthquakes recorded by Kandilli Observatory and Earthquake Research Institute stations. Considering back azimuth differences of each source and station path, six different broadband station pairs and 27 earthquakes were selected to determine the 1-D shear-wave velocity structures throughout the region by using an interstation method (slant stacking technique). The linearized least squares algorithm was used to obtain the …


Marine Effects On Vertical Electrical Soundings Along Shorelines, Emi̇n Uğur Ulugergerli̇ Jan 2017

Marine Effects On Vertical Electrical Soundings Along Shorelines, Emi̇n Uğur Ulugergerli̇

Turkish Journal of Earth Sciences

Onshore applications of direct current resistivity (DCR) along shorelines suffer a short-circuit-like phenomenon due to electrical current flowing through a more conductive body of water rather than ground. Our study of the numerical simulation of DCR data with a three-dimensional forward model demonstrated that the apparent resistivity was reduced as a function of the sea depth and the distance of measurement site to the shoreline. Furthermore, it was concluded that the "marine effects" on DCR data (i.e. reduction in apparent resistivity) become nonnegligible as the ratio of half-electrode expansion (AB/2) to the distance to the shoreline is larger than one. …


Active Faults In The Anatolian-Aegean Plate Boundary Region With Nubia, Ali̇ Değer Özbakir, Rob Govers, Rinus Wortel Jan 2017

Active Faults In The Anatolian-Aegean Plate Boundary Region With Nubia, Ali̇ Değer Özbakir, Rob Govers, Rinus Wortel

Turkish Journal of Earth Sciences

Convergence of the Africa, Arabia, and Eurasia plates and the westward escape of Anatolia have resulted in an evolving plate boundary zone in the Eastern Mediterranean. The current location and nature of the plate boundary between the Anatolian and the African plate is difficult to trace due to the scattered crustal earthquakes and the absence of deep ones. We examine various types and locations for the plate boundary as constrained by seismicity, seismic reflection studies, tomographic studies, and geodetic measurements and we use a spherical plane stress finite element model to test these possibilities. In our regional model, we impose …


Maastrichtian-Thanetian Planktonic Foraminiferal Biostratigraphy And Remarks On The K-Pg Boundary In The Southern Kocaeli Peninsula (Nw Turkey), Volkan Sarigül, Aynur Hakyemez, Okan Tüysüz, Şengül Can Genç, İsmai̇l Ömer Yilmaz, Ercan Özcan Jan 2017

Maastrichtian-Thanetian Planktonic Foraminiferal Biostratigraphy And Remarks On The K-Pg Boundary In The Southern Kocaeli Peninsula (Nw Turkey), Volkan Sarigül, Aynur Hakyemez, Okan Tüysüz, Şengül Can Genç, İsmai̇l Ömer Yilmaz, Ercan Özcan

Turkish Journal of Earth Sciences

The Kocaeli Peninsula (NW Turkey) provides one of the best exposed deep marine Upper Cretaceous-Palaeocene sections in north-western Anatolia. The biostratigraphic framework from three sections, namely Belen, Bulduk, and Toylar, in the southern part of the Kocaeli Peninsula is established by means of planktonic foraminifera. A very rich planktonic foraminiferal assemblage analysed both in thin sections and washed residues records a biozonation ranging from the Contusotruncana contusa (CF6) Zone (Maastrichtian) to the Globanomalina pseudomenardii (P4) Zone (Thanetian). Although a major part of the biozones in the studied interval is clearly defined, the upper three zones (CF1-3) of the latest Maastrichtian …


Sulfur Isotope Characteristics Of The Permian Vhms Deposits In Tasik Chini District, Central Belt Of Peninsular Malaysia, Mohd Basril Iswadi Basori, Khin Zaw, Robert Ross Large, Wan Fuad Wan Hassan Jan 2017

Sulfur Isotope Characteristics Of The Permian Vhms Deposits In Tasik Chini District, Central Belt Of Peninsular Malaysia, Mohd Basril Iswadi Basori, Khin Zaw, Robert Ross Large, Wan Fuad Wan Hassan

Turkish Journal of Earth Sciences

Sulfur isotope data from sulfide and sulfate minerals have been measured from the two typical examples of the Permian volcanic-hosted massive sulfide (VHMS) deposits at the Tasik Chini district in the Central Belt of Peninsular Malaysia. In this study, we present the sulfur isotope data for 33 sulfide minerals and 23 barite samples from two VHMS deposits in the Tasik Chini district. Sulfides show a narrow range of sulfur values from -2.9%o to +8.30%o, which can be interpreted to be derived from a mixed sulfur source of reduced seawater sulfate with the possible addition of magmatic sulfur. Sulfate sulfur in …


Suborbital Graphs For The Atkin-Lehner Group, Tuncay Köroğlu, Bahadir Özgür Güler, Zeynep Şanli Jan 2017

Suborbital Graphs For The Atkin-Lehner Group, Tuncay Köroğlu, Bahadir Özgür Güler, Zeynep Şanli

Turkish Journal of Mathematics

We investigate suborbital graphs for an imprimitive action of the Atkin-Lehner group on a maximal subset of extended rational numbers on which a transitive action is also satisfied. Obtaining edge and some circuit conditions, we examine some combinatorial properties of these graphs.


Topological Entropies Of A Class Of Constrained Systems, Yanni Ma, Bingzhe Hou Jan 2017

Topological Entropies Of A Class Of Constrained Systems, Yanni Ma, Bingzhe Hou

Turkish Journal of Mathematics

In this paper, we consider a class of constrained systems named double upper bounds $(p,q)$-constrained systems ($(p,q)$-DUB systems in brief), which are one-dimensional subshifts of finite type. We determinate the topological entropies (Shannon capacities) $C(p,q)$ of all $(p,q)$-DUB systems and consequently order all $(p,q)$-DUB systems according to the size of topological entropies. In particular, $C(p, \infty)=C(p+1, p+1)$ are the only equalities possible among the topological entropies of $(p,q)$-DUB systems.


$\Mathcal{Vw}$-Gorenstein Complexes, Renyu Zhao, Wei Ren Jan 2017

$\Mathcal{Vw}$-Gorenstein Complexes, Renyu Zhao, Wei Ren

Turkish Journal of Mathematics

Let $\mathcal{V,W}$ be two classes of modules. In this paper, we introduce and study $\mathcal{VW}$-Gorenstein complexes as a common generalization of $\mathcal{W}$-complexes, Gorenstein projective (resp., Gorenstein injective) complexes, and $G_C$-projective (resp., $G_C$-injective) complexes. It is shown that under certain hypotheses a complex $X$ is $\mathcal{VW}$-Gorenstein if and only if each $X^n$ is a $\mathcal{VW}$-Gorenstein module. This result unifies the corresponding results of the aforementioned complexes. As an application, the stability of $\mathcal{VW}$-Gorenstein complexes is explored.


Generalized $\Ast$-Lie Ideal Of $\Ast$-Prime Ring, Seli̇n Türkmen, Neşet Aydin Jan 2017

Generalized $\Ast$-Lie Ideal Of $\Ast$-Prime Ring, Seli̇n Türkmen, Neşet Aydin

Turkish Journal of Mathematics

Let $R$ be a $\ast$-prime ring with characteristic not $2,$ $\sigma, \tau:R\rightarrow R$ be two automorphisms, $U$ be a nonzero $\ast$-$\left( \sigma,\tau\right) $-Lie ideal of $R$ such that $\tau~$commutes with $\ast$, and $a,b$ be in $R.$ $\left( i\right) $ If $a\in S_{\ast}\left( R\right) $ and $\left[ U,a\right] =0$, then $a\in Z\left( R\right) $ or $U\subset Z\left( R\right) .$ $\left( ii\right) $ If $a\in S_{\ast}\left( R\right) $ and $\left[ U,a\right] _{\sigma,\tau}\subset$ $C_{\sigma,\tau}$, then $a\in Z\left( R\right) ~$or$~U\subset Z\left( R\right) .$ $\left( iii\right) $ If $U\not \subset Z\left( R\right) $ and $U\not \subset C_{\sigma,\tau}$, then there exists a nonzero $\ast$-ideal $M$ of …


On Golden Semisymmetric Metric $F$-Connections, Aydin Gezer, Çağri Karaman Jan 2017

On Golden Semisymmetric Metric $F$-Connections, Aydin Gezer, Çağri Karaman

Turkish Journal of Mathematics

In this paper, we construct a golden semisymmetric metric $F$-connection on a locally decomposable golden Riemannian manifold and investigate some properties of its curvature, conharmonic curvature, Weyl projective curvature, and torsion tensors. Moreover, we define the transposed connection of this connection and study its curvature properties.


Singular Dirac Systems In The Sobolev Space, Eki̇n Uğurlu Jan 2017

Singular Dirac Systems In The Sobolev Space, Eki̇n Uğurlu

Turkish Journal of Mathematics

In this paper we construct Weyl's theory for the singular left-definite Dirac systems. In particular, we prove that there exists at least one solution of the system of equations that lies in the Sobolev space. Moreover, we describe the behavior of the solution belonging to the Sobolev space around the singular point.


Some Theorems For A New Type Of Multivalued Contractivemaps On Metric Space, Gonca Durmaz Jan 2017

Some Theorems For A New Type Of Multivalued Contractivemaps On Metric Space, Gonca Durmaz

Turkish Journal of Mathematics

In this paper, taking into account the function $\theta $, we introduce a new type of contraction for multivalued maps on metric space. This new concept includes many known contractions in the literature. We then present some fixed point results for closed and bounded set valued maps on complete metric space. Finally, we provide an example to show the significance of the investigation of this paper.