Digital Commons Network^™

Solidified Floating Organic Drop Microextraction And Spectrophotometric Determination Of Vanadium In Water Samples, Shayessteh Dadfarnia, Ali Mohammad Haji Shabani, Akram Mirshamsi

Turkish Journal of Chemistry

Solidified floating organic drop microextraction (SFODME) was used as a sample preparation method prior to spectrophotometric determination of trace amounts of vanadium in water samples. 8-Hydroxyquinoline (oxine) was used as the chelating agent. The main parameters affecting the performance of SFODME, such as pH, concentration of oxine, extraction time, sample and organic phase volume, extraction temperature, and the nature of the organic solvent, were optimized. Under the optimized conditions, an enhancement factor of 38, detection limit of 0.97 \mu g L^{-1}, and good relative standard deviation of \pm 3.9% at 10 \mu g L^{-1} were obtained. The method was successfully …

Chemistry Of Dibenzobarallene, Moustafa A. Gouda, Moged A. Berghot, Khaled M. Elattar, Abd El Galil M. Khalil

Turkish Journal of Chemistry

This review represents a systematic and comprehensive survey of the methods of syntheses and chemical reactivity of dibenzobarallene. This compound is an important intermediate for the synthesis of useful and novel heterocycle systems.

In Situ Catalytic Activities Of 1,3-Dialkyltetrahydropyrimidinium Salts/[Rucl_2(P-Cymene)]_2 System For Transfer Hydrogenation Reactions, Emi̇ne Özge Özcan, Deni̇z Mercan, Nevi̇n Gürbüz, Engi̇n Çeti̇nkaya, Beki̇r Çeti̇nkaya, İsmai̇l Özdemi̇r

Turkish Journal of Chemistry

Hydrogen-transfer reduction processes are attracting increasing interest from synthetic chemists in view of their operational simplicity. In the present study novel ruthenium carbene complexes were generated in situ and tested for their transfer hydrogenation reactions. The in situ prepared 3 component 1,3-dialkyltetrahydropyrimidinium salts (LHX)/[RuCl_2(p-cymene)]_2 and KOH catalyzed quantitatively the transfer hydrogenation of ketones under mild reaction conditions in 2-propanol.

Electrochemical Impedance Spectroscopy Study On Intercalation And Anomalous Diffusion Of Alcl_4^- Ions Into Graphite In Basic Molten Salt, Ali Ehsani, Mohammad Ghasem Mahjani, Majid Jafarian

Turkish Journal of Chemistry

Electrochemical impedance spectroscopy (EIS) was employed to investigate diffusion of AlCl_4^- ions in basic (AlCl_3-NaCl-KCl) molten salt. Nyquist plots in different DC offset potentials showed finite and restricted aluminum ion diffusion due to insertion and blocking in the graphite electrode. The general Warburg, open Warburg, and short Warburg impedance in the complex Nyquist plot of this system showed the anomalous diffusion behavior of the ions in the graphite electrode. The diffusion coefficient of the AlCl_4^- ions was calculated from the slope of the Warburg line in a totally blocking film in the graphite electrode and was found to be 2.8 …

Studies On The Mechanism Of Phosphazene Ring-Opening Polymerization (Rop), Selen Bi̇lge

Turkish Journal of Chemistry

In this study, the ring-opening polymerization (ROP) of cyclic trimer N_3P_3Cl_6 catalyzed by [Et_3Si(N_3 P_3Cl_6)][CHB_{11}H_5Br_6] (3) obtained from the reaction of N_3P_3Cl_6 (1) and Et_3Si(CHB_{11}H_5Br_6) (2) at room temperature was investigated. This provided a unique opportunity to explore the polymerization mechanism. The coordinatively unsaturated cation [N_3P_3Cl_5]^+ is responsible for the ROP of N_3P_3Cl_6, and is formed by the intramolecular elimination of Et_3SiCl from 3. The detection of Et_3SiCl by ^1H-NMR as the catalysis proceeded offers new evidence for the formation of [N_3P_3Cl_5]^+. The progress of the catalysis was followed using ^{31} P-NMR and revealed the build-up of a polymer. Cyclic …

Preparation And Characterization Of A Series Of Thiourea Derivatives As Phase Change Materials For Thermal Energy Storage, Cemi̇l Alkan, Yusuf Tek, Derya Kahraman

Turkish Journal of Chemistry

A series of solid-liquid phase change materials, thiourea derivatives, were prepared via condensation of thiourea with the respective carboxyl chlorides (lauroyl chloride, myristoyl chloride, and palmitoyl chloride) and were then characterized by using FT-IR, ^1H-NMR, differential scanning calorimetry (DSC), and thermogravimetric (TG) analysis. The thiourea derivatives (1,3-didodecanoyl thiourea, 1,3-ditetradecanoyl thiourea, and 1,3-dihexadecanoyl thiourea) were structurally symmetric and had long alkyl groups to crystallize. Thermal analysis by DSC and spectroscopic investigation by FT-IR spectroscopy were performed on the samples before and after thermal cycling tests to determine thermal reliability. The maximum latent heats of melting and freezing of the thiourea derivatives …

Synthesis Of Starch-G-Poly(Acrylic Acid-Co-2-Hydroxy Ethyl Methacrylate) As A Potential Ph-Sensitive Hydrogel-Based Drug Delivery System, Mohammad Sadeghi

Turkish Journal of Chemistry

The present work focused on the design of a drug delivery system (DDS) based on pH-sensitive hydrogel. The hydrogels were prepared via graft copolymerization of mixtures of acrylic acid (AA) and 2-hydroxy ethyl methacrylate (HEMA) onto starch backbones by a free radical polymerization technique. Sodium bicarbonate (NaHCO_3) was added to function as a foaming agent under acidic conditions, rendering the hydrogels to be porous. The porous structure of the hydrogel was essential in this system to yield a large surface area so that 5-fluorouracil (5-FU) release could be facilitated. The hydrogel, thus prepared, possessed a porous structure as determined by …

Electrocatalytic Oxidation Of Methanol At Pd And Pt Ad-Layer Modified Au(111) Electrodes In Alkaline Solution, Süleyman Koçak, Zekerya Dursun, Fatma Ni̇l Ertaş

Turkish Journal of Chemistry

The electrochemical oxidation of methanol was investigated by using various ad-layer modified Au(111) electrodes in alkaline media in comparison to Au(111), polycrystalline Pd, and polycrystalline Pt electrodes. Catalytic activity of gold toward methanol oxidation has tended to increase in more alkaline media, as reflected in the oxidation peak in the concentration range of NaOH (0.1-3.0 M) studied here. The oxidation peak potential of methanol shifted to more negative potentials, indicating a pH-dependent surface reaction. Among the electrodes studied, single-crystal gold electrode surfaces modified with Pd and Pt ad-layers displayed the highest catalytic activity for methanol oxidation. Additional shifts of about …

A New And Simple Procedure For The Polarographic Speciation And Determination Of Trace Inorganic As(Iii) And As(V) Species, Ülkü Ünal, Güler Somer

Turkish Journal of Chemistry

A new and simple differential pulse polarographic method was developed for the trace determination of As(III) and As(V) species in the same sample. Among several electrolytes, 0.1 M HCl was found to be the most suitable. As(III) had 3 peaks in this medium, and the peak at --0.82 V was chosen because of its peak shape and response to standard additions. In this medium, the limit of detection for As(III) was found to be 1.5 \times 10^{-7} M. Since As(V) is not electroactive, it had to be reduced first into As(III). For this purpose, KI in an acidic and hot …

A Computational Study On Substituted Diazabenzenes, Selçuk Gümüş

Turkish Journal of Chemistry

The results of computational calculations on the aromaticity of the monosubstituted diazabenzenes (pyridazine, pyrimidine, and pyrazine) are reported herein. The aromaticity of the parent heterocycle was enhanced by substitution of strong electron-withdrawing groups. The effects of the position of the substituent on the aromaticity and the stability of the system were also investigated by studying all possible derivatives of the systems.

Polyphenolic Compounds From Geranium Purpureum Vill. Growing In Turkey, Di̇dem Şöhretoğlu, Mahmut Koray Sakar, Olov Sterner

Turkish Journal of Chemistry

Two new flavonol derivatives, Geranioside A (kaempferol 3-[3-(\alpha-rhamnopyranosyl)-4-oxy-5-hydroxy-6-methyl-3,4-dihyropyran-2H- 2-pyranoside]) (1) and Geranioside B (quercetin 3-[3-(\alpha-rhamnopyranosyl)- 4-oxy-5-hydroxy-6-methyl-3,4-dihyropyran-2H-2-pyranoside]) (2), along with 5 known flavonols (quercetin (3), kaempferol (4), quercetin 4'-O-\beta -glucopyranoside (5), quercetin 3-O-\beta -glucopyranoside (6), and kaemferol-3-O-\beta -glucopyranoside (7)), a gallic acid derivative (methyl gallate (8)), and a hydrolysable tannin (pusilagin (9)), were isolated from the aerial parts of Geranium purpureum. The structures of the isolated compounds were elucidated on the basis of UV, IR, and 1D- and 2D-NMR experiments as well as TOF-MS.

Amphiphilic And Chiral Unsymmetrical Perylene Dye For Solid-State Dye-Sensitized Solar Cells, Hurmus Refiker, Hüri̇ye İci̇l

Turkish Journal of Chemistry

A novel amphiphilic, unsymmetrically substituted N-((2S)-2-aminohexanoic acid)-N'-[(S)-1-phenylethyl]-3,4,9,10- perylenetetracarboxydiimide with 2 different chiral centers was synthesized and characterized. Chiral amphiphilicity, which can be tunable between hydrophilic and hydrophobic parts, is responsible for controlled self-assembly through intermolecular hydrogen bonding (N-H \cdots O). The product showed high thermal stability but partial solubility in common organic solvents. We observed 2 isosbestic points at 533 and 611 nm, confirming the presence of overlapped monomer and excimer emissions in the temperature range of 10-80 °C. Fluorescence quenching in m-cresol was attributed to charge-transfer interactions. Importantly, the excited state of the chiral dye can decay only by …

Facile And Convenient Synthesis Of Pyrimidine, 4h-3,1-Benzoxazin-4-One, Pyrazolo[5,1-B]Quinazoline, Pyrido[1,2-A]Quinazoline, And Chromeno[3' ,4' :4,5]Pyrido[1,2-A]Quinazoline Derivatives, Yousry A. Ammar, Samir Bondock, Abdallah G. El-Sehmi, Mohamed S.A El_Gaby, Ahmed M. Fouda, Hamdy Kh. Thabet

Turkish Journal of Chemistry

A convenient synthesis of a series of pyrimidine, 4H-3,1-benzoxazin-4-one, pyrazolo[5,1-b]quinazoline, pyrido[1,2-a]quinazoline, and chromeno[3' ,4' :4,5]pyrido[1,2-a]quinazoline derivatives, via the reactions of versatile and readily accessible methyl 2-(2-cyanoacetamido)benzoate (1) with the appropriate reagents, is described here.

Synthesis And Antimicrobial Activity Of Novel 2-(Pyridin-2-Yl)Thieno[2,3-D]Pyrimidin-4 (3h)-Ones, Nitin G. Haswani, Sanjaykumar B. Bari

Turkish Journal of Chemistry

In the present study, some new 2-(pyridin-2-yl)thieno[2,3-d] pyrimidin-4(3H)-ones derivatives (IIa-o) were synthesized. The target compounds (IIa-o) were synthesized through the acid catalyzed condensation of 2-cyano, 3-cyano, and 4-cyano-pyridines with various 2-amino-3-carbethoxythiophenes (Ia-e). All thiophene derivatives were synthesized by Gewald reaction. The structures of the newly synthesized compounds were confirmed by UV-Visible, FT-IR, ^1H-NMR, and mass spectral studies. All synthesized compounds were evaluated for their antimicrobial activity against various gram-positive and gram-negative bacterial and fungal strains. Amongst the synthesized compounds IIa, IIb, IId, IIe, and IIm were found to be active.

Chemistry Of 2-Aminothiophene-3-Carboxamide And Related Compounds, Moustafa A. Gouda, Moged A. Berghot, Ghada E. Abd El-Ghani, Khaled M. Elattar, Abd El Galil M. Khalil

Turkish Journal of Chemistry

This review describes the synthesis and reactions of 2-aminothiophene-3-carboxamides as building blocks for the syntheses of polyfunctionalized heterocyclic compounds.

Simultaneous Determination Of Copper And Cadmium In Environmental Water And Tea Samples By Adsorptive Stripping Voltammetry, Mohammad Bagher Gholivand, Alireza Pourhossein, Mohsen Shahlaei

Turkish Journal of Chemistry

A sensitive and selective method for the simultaneous determination of copper and cadmium in seawater, river water, and tea samples is described. The method is based on the adsorptive accumulation of 2,2--dithiosalicylic acid complexes of these elements onto a hanging mercury drop electrode, followed by reduction of adsorbed species by voltammetric scan using differential pulse modulation. Optimal analytical conditions were as follows: ligand concentration of 11 nM, pH of 9.5, and an adsorption potential at --300 mV versus Ag/AgCl, with an accumulation time of 60 s. The peak currents are proportional to the concentration of copper and cadmium over the …

The Sorption Of Cadmium(Ii) Ions On Mercerized Rice Husk And Activated Carbon, Mas Rosemal Hakim Mas Haris, Nor Aimi Abdul Wahab, Chong Wan Reng, Baharin Azahari, Kathiresan Sathasivam

Turkish Journal of Chemistry

This work describes the removal of Cd(II) ions in aqueous solution by unmodified and base-modified rice husk (RH) as compared to that by activated carbon (AC). Mercerization of RH was carried out by using dilute solutions (0.013 M) of NaOH, KOH, and Ca(OH)_2. The experiments were conducted in duplicate under 1-batch and 2-batch treatments. In the 1-batch treatment, a fresh 200 mg of each adsorbent was used to study the sorption of the Cd(II) ions from 100-mL solutions at an initial concentration of 5 mg L^{-1}. The adsorption percentage increased in the order of unmodified RH (80.13 \pm 0.46%) < Ca(OH)_2-modified RH (90.74 \pm 0.18%) < NaOH-modified RH (93.36 \pm 0.23%) \le KOH-modified RH (93.78 \pm 0.27%) < AC (98.4 \pm 0.18%). In the 2-batch treatment, a fresh 100 mg of each adsorbent was placed in 100-mL solutions at an initial concentration of 5 mg L^{-1} of Cd(II) ions for 30 min, and the resulting solutions were filtered. The filtrates were subjected to another fresh 100 mg of each adsorbent for an additional 30 min. The percentage removal of the metal ion using the 2-batch treatment for unmodified RH, base-modified RH, and AC was 97.71%, 98.00 \pm 1.00%, and nearly 100%, respectively.

Synthesis And Structural Analysis Of A Regular Cu-Mg-Al Hydrotalcite-Like Compound, Jiansong Wu, Yingkai Xiao, Yuping Liu, Wanbang Xu, Meifang Liang, Jian Cheng, Jianping Wan, Lingzhu Chen

Turkish Journal of Chemistry

A fine-quality, regular Cu-Mg-Al hydrotalcite-like compound was synthesized via the glycothermal method using CuCl_2 \cdot 2H_2O, MgCl_2 \cdot 6H_2O, AlCl_3 \cdot 6H_2O, and Na_2CO_3 as raw materials and sodium hydroxide as the precipitant. Hydrotalcite samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric-differential thermal analysis, and Brunauer-Emmett-Teller N_2 surface area measurements. The influence of glycol content on the characteristics of the sample was investigated. The results show that the glycol content in the system had a greater impact on regular hydrotalcite with an intercalated structure. A Cu-Mg-Al hydrotalcite-like compound with a well-defined …

Determination Of Ni(Ii) With Picolinaldehyde-4-Phenyl-3-Thiosemicarbazone Used As A Chromogenic Reagent In A Nonionic Micellar System, Aamna Balouch, Muhammad Iqbal Bhanger, Farah Naz Talpur, Willie L. Hinze

Turkish Journal of Chemistry

Spectrophotometric determination of Ni(II) was carried out using picolinaldehyde-4-phenyl-3-thiosemicarbazone (PAPT) as a complexing/chromogenic reagent. The possibility of using a micellar system was explored to enhance the degree of detection and allow a more sensitive spectrophotometric method for the determination of nickel ions. The anionic surfactant Triton X-100 greatly enhanced the molar absorptivity and limit of detection relative to that observed with bulk water or an organic solvent. The linear calibration graphs were obtained for 0.5-2.0 mg L^{-1} and 0.001-1.0 mg L^{-1} of Ni(II) in aqueous and surfactant media, respectively. Using this approach, the limit of detection for the PAPT-Ni(II) complex …

Cover And Contents

Turkish Journal of Chemistry

No abstract provided.

Architecture Value Mapping: Using Fuzzy Cognitive Maps As A Reasoning Mechanism For Multi-Criteria Conceptual Design Evaluation, Atmika Singh

Doctoral Dissertations

"The conceptual design phase is the most critical phase in the systems engineering life cycle. The design concept chosen during this phase determines the structure and behavior of the system, and consequently, its ability to fulfill its intended function. A good conceptual design is the first step in the development of a successful artifact. However, decision-making during conceptual design is inherently challenging and often unreliable. The conceptual design phase is marked by an ambiguous and imprecise set of requirements, and ill-defined system boundaries. A lack of usable data for design evaluation makes the problem worse. In order to assess a …

Alloy Dissolution In Argon Stirred Steel, Darryl S. Webber

Doctoral Dissertations

"Alloying is required for the production of all steel products from small castings to large beams. Addition of large quantities of bulk alloys can result in alloy segregation and inconsistent alloy recovery. The objective of this research was to better understand alloy dissolution in liquid steel especially as it relates to Missouri S&Ts' patented continuous steelmaking process. A 45-kilogram capacity ladle with a single porous plug was used to evaluate the effect of four experimental factors on alloy dissolution: alloy species, alloy size or form, argon flow rate, and furnace tap temperature. Four alloys were tested experimentally including Class I …

Diesel Particulate Matter Dispersion Analysis In Underground Metal/Nonmetal Mines Using Computational Fluid Dynamics, Yi Zheng

Doctoral Dissertations

"Diesel Particulate Matter (DPM) is a natural by-product from operating diesel engines. Since diesel power is a major source of energy for mining operations today, the adverse health effects of DPM are of a great concern. To thoroughly resolve DPM problems, it is critical that DPM propagation characteristics be understood to arrive at a sensible and practical method for addressing DPM-related issues. To achieve this, a computational fluid dynamics (CFD) method is used to simulate DPM dispersion and to predict its concentration distribution. Industrial field studies were reconstructed to evaluate the possibility of different CFD models. Experiments were also carried …

Order Acceptance And Scheduling: A Taxonomy And Review, Susan A. Slotnick

Business Faculty Publications

Over the past 20 years, the topic of order acceptance has attracted considerable attention from those who study scheduling and those who practice it. In a firm that strives to align its functions so that profit is maximized, the coordination of capacity with demand may require that business sometimes be turned away. In particular, there is a trade-off between the revenue brought in by a particular order, and all of its associated costs of processing. The present study focuses on the body of research that approaches this trade-off by considering two decisions: which orders to accept for processing, and how …

Investigating Peer Review As An Intentional Learning Strategy To Foster Collaborative Knowledge-Building In Students Of Instructional Design, Jennifer M. Brill, Charles B. Hodges

Leadership, Technology & Human Development: Faculty Publications

Peer review has been advocated for as an intentional strategy to support the knowledge and skill attainment of adult learners preparing for professional practice, including those students preparing for instructional design and technology practice. The purposes of this article are to discuss the practical application of peer review as an instructional strategy by articulating its use in both face-to-face and online Instructional Design courses and to formulate directions for future research on the use of peer review in instructional practice. Findings from a literature review of student-to-student peer review and the authors' experiences with the use of peer review in …

Tennessee Archivist 34, No.1, Society Of Tennessee Archivists

Tennessee Archivist newsletters

Winter 2011 issue of the Tennessee Archivist, a newsletter produced by the Society of Tennessee Archivists.

The Impact Of Infectious Disease On Chronic Disease: A Review Of Contemporary Findings, Wendy Berke

Journal of Social, Behavioral, and Health Sciences

Infectious diseases are among the top causes of death in adults and children. Chronic diseases such as cardiovascular disease and cancer are among the top causes of death in adults. Associations between bacterial and viral infectious agents and subsequent development of chronic disease have been made in the past but are currently being reexamined with more rigor and specificity. This review examines infectious disease agent causes and associations with cancer, cardiovascular disease, metabolic disease, and neurodegenerative disease. These associations will impact future research, surveillance, treatment, and prevention of both infectious and chronic diseases.

Locating Mineral Exploration Targets Using A Geographical Information System, Finnian O'Connor

Conference papers

This paper outlines the research and development of a complete open source geographic information system (GIS) that offers real-time geoprocessing over the Internet. The premise of the geoprocessing is to locate mineral exploration targets that have high potential for success based on parameters chosen by the end-user of the system.

Components integrated in the system include a spatial database PostGIS, a GIS processing engine GRASS, a GIS server GeoServer, a web server Apache, and front-end technologies OpenLayers and GeoExt. Appropriate data was sourced from the Geological Survey of Ireland to be used for the geoprocessing.

With all the components of …

Spatio-Temporal Variations In Soil Moisture And Physicochemical Properties Of A Typical Semiarid Sand-Meadow-Desert Landscape As Influenced By Land Use, L. Duan, T. Liu, X. Wang, G. Wang, L. Ma, Y. Luo

Civil & Environmental Engineering Faculty Publications

A good understanding of the interrelations between land cover alteration and changes in hydrologic conditions (e.g., soil moisture) as well as soil physicochemical properties (e.g., fine soil particles and nutrients) is crucial for maintaining the fragile hydrologic and environmental conditions of semiarid land, such as the Horqin Sandy Land in China, but is lacking in existing literature. The objectives of this study were to examine: (1) spatio-temporal variations of soil moisture and physicochemical properties in semiarid land; and (2) how those variations are influenced by land cover alteration. Using the data collected in a 9.71 km2 well-instrumented area of the …

Weighted And Filtered Mutual Information: A Metric For The Automated Creation Of Panoramas From Views Of Complex Scenes, Thomas Keane

Theses

To contribute a novel approach in the field of image registration and panorama creation, this algorithm foregoes any scene knowledge, requiring only modest scene overlap and an acceptable amount of entropy within each overlapping view. The weighted and filtered mutual information (WFMI) algorithm has been developed for multiple stationary, color, surveillance video camera views and relies on color gradients for feature correspondence. This is a novel extension of well-established maximization of mutual information (MMI) algorithms. Where MMI algorithms are typically applied to high altitude photography and medical imaging (scenes with relatively simple shapes and affine relationships between views), the WFMI …