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Oxidative Coupling Of Methane On Lnba_{2}Cu_{3}O_{7-X} Superconductors, N. T. Shamilov, V. P. Vislovskii, E. A. Mamedov, S. M. Aliyev, A. I. Suleimanov, E. G. Ismailov Jan 1996

Oxidative Coupling Of Methane On Lnba_{2}Cu_{3}O_{7-X} Superconductors, N. T. Shamilov, V. P. Vislovskii, E. A. Mamedov, S. M. Aliyev, A. I. Suleimanov, E. G. Ismailov

Turkish Journal of Chemistry

The superconducting oxides LnBa_{2}Cu_{3}O_{7-x} (Ln=Y, Gd, Er, Yb, Lu) showed poor selectivity in the oxidative coupling of methane. The addition of 0.5 mol. %Li_{2}O to these materials considerably enhanced the yield of C_{2} hydrocarbons. This effect was related to both lower redox property and higher basicity of Li-doped catalysts as compared to those of undoped ones.

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An Amperometric Biosensor For The Determination Of Organophosphorus Pesticides, Azmi Telefoncu Jan 1996

An Amperometric Biosensor For The Determination Of Organophosphorus Pesticides, Azmi Telefoncu

Turkish Journal of Chemistry

Organophosphorus pesticides are inhibitors of cholinesterase and this enzyme is used as a monitoring system for pesticides containing organophosphorus compounds. The decrease in activity of cholinesterase is monitored by the choline sensor and is correlated to the concentration of pesticide present in solution. According to this observation a biosensor for pesticides was determined. This biosensor consists of a Clark oxygen electrode, modified with cellulose acetate and dialysis membranes. Between the two membranes there are two immobilized enzymes: acetyl-cholinesterase and choline oxidase.

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Deacidification Of High Acid Olive Oil By Immobilized Lipase, Ayşe Makasçi, Kadir Arisoy, Azmi Telefoncu Jan 1996

Deacidification Of High Acid Olive Oil By Immobilized Lipase, Ayşe Makasçi, Kadir Arisoy, Azmi Telefoncu

Turkish Journal of Chemistry

The acidity reduction of high acid oils prior to refining could be an attractive application for industry. In this study the enzymatic deacidification degummed and dewaxed olive oil with a high free fatty acid content, catalysed by an immobilized lipase was optimzed (Novozym 435). The optimum amount of substrate for synthesizing trigliycerides was the necessary stoichiometric amount of fatty acid and glycerol. The mixing was performed with a mechanical stirrer and the dehydration was performed by vacuum pump or by bubbling dry nitrogen. The dehydration rate was faster than the deacidification rate. The four parameters chosen for this experimental plan: …

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A New Flavanone From Teucrium Alyssifolium, G. Topcu, C. Eris, S. Kurucu A. Ulubelen Jan 1996

A New Flavanone From Teucrium Alyssifolium, G. Topcu, C. Eris, S. Kurucu A. Ulubelen

Turkish Journal of Chemistry

From the aerial parts of {\it Teucrium alyssifolium} in addition to previously obtained {\it neo-}clerodane diterpenoids, a new flavanone alysifolinone and three flavones cirsiliol, cirsilineol and luteolin-6,7,3', 4'-tetramethyl ether, were isolated. The structure of the compounds was established by spectral data, and by TLC comparison for the known compounds. Keywords: Teucrium alyssifolium, Lamiaceae, flavanone, alysifolinone, flovones.

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Adsorption Of Monovalent Cationic Dyes On Some Silicates, Oğuz İnel, Ayşegül Aşkin (Börekçi̇) Jan 1996

Adsorption Of Monovalent Cationic Dyes On Some Silicates, Oğuz İnel, Ayşegül Aşkin (Börekçi̇)

Turkish Journal of Chemistry

Adsorption of two cationic dyes, methylene blue (MB) and malachite green (MG), was studied on the bentonite, sepiolite and zeolite samples by the batch equilibration technique using a spectrophotometer. In addition, cation exchange capacities (CEC) of samples were determined by NH_4^{+} saturation using Kjeldhal distillation. The adsorption data was found to conform with the Langmuir equation within the concentration range studied, and Langmuir constants were determined for each of the samples. It was observed that the amount of dyes adsorbed was in excess of CEC in the case of bentonite and sepiolite. The adsorption capacities of the samples for both …

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Investigation Of Adsorption Isotherms Used For Wool Dyeing By Aqueous Extraction Of Cehri Fruit (Fructus Rhamni Petiolari) And Dyeing Of Wool And Silk Accompanied By Various Mordants, A. Haluk Aydin, Fuat Güzel, Zeki Tez Jan 1996

Investigation Of Adsorption Isotherms Used For Wool Dyeing By Aqueous Extraction Of Cehri Fruit (Fructus Rhamni Petiolari) And Dyeing Of Wool And Silk Accompanied By Various Mordants, A. Haluk Aydin, Fuat Güzel, Zeki Tez

Turkish Journal of Chemistry

In this study, adsorption isotherms were obtained by processing wool with dyestuff solutions of different concentrations extracted from cehri fruit with water. These isotherms follow the Nernst equation; the Nernst constant was determined and interpreted. In addition, wool and silk fibres were dyed with the same dyestuff solution and various mordants. Colours having a high fastness which could be used on an industrial scale were produced.

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The Effect Of Examination Stress On The Levels Of Zn^{2+}, Total Protein, Albumin In Serum And Carbonic Anhydrase Isoenzymes In Erythrocytes, Nazan Demi̇r, Yaşar Demi̇r, Ali Yildirim, Ö. İrfan Küfrevi̇oğlu, Ebubekir Bakan Jan 1996

The Effect Of Examination Stress On The Levels Of Zn^{2+}, Total Protein, Albumin In Serum And Carbonic Anhydrase Isoenzymes In Erythrocytes, Nazan Demi̇r, Yaşar Demi̇r, Ali Yildirim, Ö. İrfan Küfrevi̇oğlu, Ebubekir Bakan

Turkish Journal of Chemistry

In this study, the levels of Zn^{2+}, total protein and albumin in the serums of students with temporarily examination stress without any physical illnes were determined and the relationship between these values was evaluated. Furthermore, the change in the activity of carbonic anhydrase metaloenzyme with Zn^{2+} and in the rates of carbonic anhydrase I and carbonic anhydrase II were also investigated. With this aim, blood samples were taken from 100 students just before examination and from 20 control subjects. Zn^{2+} levels were determined enzymatically, while total protein and albumin assays were done with an autoanalyzer. Carbonic anhydrase activity was measured …

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Synthesis Of 2,4-Dihydro-4-(2-Phenylethyl)-5-(Isomeric Pyridyl)-3h-1,2,4-Triazole-3-Thiones And Their Derivatives., Rashid Iqbal, Khosrow Zamani, Nasim H. Rama Jan 1996

Synthesis Of 2,4-Dihydro-4-(2-Phenylethyl)-5-(Isomeric Pyridyl)-3h-1,2,4-Triazole-3-Thiones And Their Derivatives., Rashid Iqbal, Khosrow Zamani, Nasim H. Rama

Turkish Journal of Chemistry

Intramolecular cyclization of the three isomeric 1,4-disubstituted thiosemicarbazides 3(a-c) in aqueous sodium hydroxide was attempted to obtain 2,4-dihydro-4-(2-phenylethyl)-5-(isomeric pyridyl)- 3H-1,2,4-triazole-3-thiones 4(a-c). Each of the three isolated triazoles was separately treated with benzyl chloride and with chloroacetic acid to furnish the corresponding benzylthio 5(a-c) and carboxymethylthio derivatives 6(a-c), respectively

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Latex Supported Manganese(Iii) Porphyrin Catalysts For Oxidations Of Alkenes By Hydrogen Peroxide And {\It Tert-} Butyl Hydroperoxide In The Aqueous Medium, Hayrettin Türk Jan 1996

Latex Supported Manganese(Iii) Porphyrin Catalysts For Oxidations Of Alkenes By Hydrogen Peroxide And {\It Tert-} Butyl Hydroperoxide In The Aqueous Medium, Hayrettin Türk

Turkish Journal of Chemistry

Cationic polymer latexes were prepared by emulsion copolymerization of vinylbenzyl chloride and divinylbenzene followed by quaternization with trimethylamine and used as catalyst supports for 5,10,15,20-tetrakis(2, 6-dichloro-3-sulfonatophenyl)porphinatomanganese(III) chloride and 5,10,15,20-tetra(4-sul- fonatophenyl)porphinatomanganese(III) chloride. The supported catalysts and water soluble analogues were used for oxidation of styrene, 1-decene and {\it cis}-cyclooctene by hydrogen peroxide and {\it tert}- butyl hydroperoxide in the aqueous phase. The oxidation of 1-decene and {\it cis}-cyclooctene failed. In the oxidation of styrene, the porphyrin catalysts in the latex were more active than in solution. The relative molar ratios of oxidant: styrene: Mn porphyrin were 1250: 750: 1, and about …

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Synthesis, Characterization And Formation Kinetics Of Sn(Ii) And (Iv)-Schiff Base Complexes, Yakup Baran, Birgül Erk Jan 1996

Synthesis, Characterization And Formation Kinetics Of Sn(Ii) And (Iv)-Schiff Base Complexes, Yakup Baran, Birgül Erk

Turkish Journal of Chemistry

The synthesis and characterization of Sn(II) and Sn(IV) complexes of nitrogen and oxygen ligands, {\it p}-dimethyl aminophenylenesalicyladimine ( DPS), N,N'phenylenebis(salicylaldimine)(PBS) and N, N'-triethylenetetramine bis (salicylaldimine)(TTS) are reported. The structure of free ligands and their tin complexes were determined by elemental analysis, ir and nmr measurements. The kinetics of formation of the complexes were studied by stopped-flow technique at several temperatures with \mu=0.100 M (NaClO_{ 4}). Activation parameters \Delta H^{\ast} and \Delta S^{\ast} were determined.

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Structural Fusion Of Condensed Benzenoid Systems, Lemi Türker Jan 1996

Structural Fusion Of Condensed Benzenoid Systems, Lemi Türker

Turkish Journal of Chemistry

On the basis of ring topologies, some theorems for the structural fusion of condensed benzenoids are presented. It has been proved that the oddness or evenness of the fused system is dictated by the degree of fusion.

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Voltammetric Determination Of Promethazine By Platinum And Glassy Carbon Electrodes, Bengi Uslu, İnci Bi̇ryol, Sibel A. Özkan, Zühre Şentürk Jan 1996

Voltammetric Determination Of Promethazine By Platinum And Glassy Carbon Electrodes, Bengi Uslu, İnci Bi̇ryol, Sibel A. Özkan, Zühre Şentürk

Turkish Journal of Chemistry

The electrochemical oxidation of promethazine was studied by linear sweep and cyclic voltammetry on platinum and glassy carbon electrodes. The dependence of current intensities and potentials on pH, concentration, scan rate and nature of the buffer was examined. Linear calibration plots were obtained in phosphate buffer (pH 7.0) and acetate buffer (pH 4.7) for platinum and glassy carbon electrode, respectively.

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The Sterols Of Cyclamen Coum, Nurettin Yayli, Cemalettin Baltaci Jan 1996

The Sterols Of Cyclamen Coum, Nurettin Yayli, Cemalettin Baltaci

Turkish Journal of Chemistry

The structures of one major and three minor constituents of sterol fraction of the Cyclamen coum have been established as stigmasterol [(22E)- (24S)- 24-ethylcholesta-\Delta ^{5,22}-dien-\beta-ol] ({\bf 1}), Poriferasterol [22E)-(24R)-24-ethylcholesta-\Delta^{5,22}-dien-3\beta- ol] ({\bf 2}), stigma-or poriferasta-\Delta^{3,5,22} triene [(22E)-24 -ethylcholesta-\Delta^{3,5,22}-trien] ({\bf 3}) stigma-or poriferosta- \Delta^{3,5,7,22}-tetraene [(22E)-24-ethylcholesta-\Delta^{3,5,7,22}- tetraene] ({\bf 4}) by spectroscopic means (NMR, EI-MS and GC-MS).

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An Unusual Zinc-Promoted Reductive Retro-Wagner-Meerwein Rearrangement, Yavuz Taşkesenli̇gi̇l, Metin Balci Jan 1996

An Unusual Zinc-Promoted Reductive Retro-Wagner-Meerwein Rearrangement, Yavuz Taşkesenli̇gi̇l, Metin Balci

Turkish Journal of Chemistry

Bromination and dehydrobromination of exocyclic olefin {\bf 8} resulted in the formation of bromomethylene compound {\bf 9} and Wagner-Meerwein rearrangement product {\bf 10}. The dehydrobromination of {\bf 10} with potassium {\it tert}-butoxide provided the corresponding bromomethyl compound {\bf 11} in high yield. Reaction of {\bf 11} with Zn-Cu couple in methanol afforded the methyl derivative {\bf 12} and the parent olefin {\bf 8}. The unusual formation mechanism of {\bf 8} has been discussed in term of a reductive retro-Wagner-Meerwein rearrangement.

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A Novel And Stereospecific Synthesis Of Conduritol-E Via Cyclohexa-3,5-Diene-1,2-Diol, Ahmet Maras, Hasan Secen, Yasar Sütbeyaz, Metin Balci Jan 1996

A Novel And Stereospecific Synthesis Of Conduritol-E Via Cyclohexa-3,5-Diene-1,2-Diol, Ahmet Maras, Hasan Secen, Yasar Sütbeyaz, Metin Balci

Turkish Journal of Chemistry

Conduritol-E was synthesized starting from cyclohexa-3,5-diene-1,2-diol {\bf 1a} in six steps. Acetylation of the diol {\bf 1a} followed by bromination gave (2\alpha/1\beta, \,\, 3\beta, \,\, 4\beta)-1,2-dibromo-2,3- diacetoxy- 5-cyclohexene {\bf 3} as main product. KMnO_{4}-hydoxylation of the dibromide {\bf 3} followed by acetylation, Zn-elimination and hydrolysis afforded conduritol-E {\bf 5a}.

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Study Of Interaction And Solubility Parameters Of Alkyl Methacrylate Polymers By Inverse Gas Chromatography, İsmet Kaya, Eyüp Özdemi̇r, Mehmet Coşkun Jan 1996

Study Of Interaction And Solubility Parameters Of Alkyl Methacrylate Polymers By Inverse Gas Chromatography, İsmet Kaya, Eyüp Özdemi̇r, Mehmet Coşkun

Turkish Journal of Chemistry

Flory-Huggins interaction parameters (\chi) and partial molar free energies of mixing (\DeltaG^{\infty}_1) have been determined by inverse gas chromatography (i.g.c.) at temperatures 413-443 K for alkanes, acetates, ketones, aromatics, THF and methanol to estimate the polymer solubility parameters (\delta_2) of PMMA, PEMA, PİBMA and Pt-BMA. Furthermore, weight fraction activity coefficients (\alpha_1/W_1)^{\infty} of probes were calculated at infinite dilution at 413-443 K.

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The Epoxidation Of Oil Obtained From The Eastern Black Sea Fishes, Eyüp Özcan, Bahri Ülküseven Jan 1996

The Epoxidation Of Oil Obtained From The Eastern Black Sea Fishes, Eyüp Özcan, Bahri Ülküseven

Turkish Journal of Chemistry

In this study we have investigated the suitable reaction conditions for the epoxidation of the semi-refined fish oil obtained from the fishes of eastern Black Sea, with peracetic acid. Various oxidation mixtures to reach the highest epoxyd-oxygene amount have been tested mean while the effective factors were established. In order to establish some specifications of the epoxy-product. Iodine-, hydroxyl-indices and epoxyd-oxygene percents were determined. We've also tried to explain how some reaction conditions (mole ratio of acetic acid to double bond and temperature) influenced the epoxy-product.

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Artificial Maturation Of Alginite And Organic Groundmass Separated From Torbanites, Michael A. Kruge, Patrick Landais, David F. Bensley Jan 1996

Artificial Maturation Of Alginite And Organic Groundmass Separated From Torbanites, Michael A. Kruge, Patrick Landais, David F. Bensley

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The two principal organic constituents — Botryococcus-related alginite and organic groundmass — were isolated by density separation from two torbanite samples (from the Stellarton Fm., Nova Scotia, Canada and the King Cannel, Utah, USA). The groundmass consisted of degraded algal, bacterial and terrestrial plant debris. Aliquots of alginite and groundmass were separately heated in gold tubes for 24 hr. with 70 MPa confining pressure, at fixed temperatures ranging between 250 and 375°C. The 250, 300 and 325°C experiments run on the alginite produced very low yields of CHCl3-extractable organic matter (EOM), indicating that very little of the generation potential …

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Flash Pyrolysis Of Anthropogenic And Natural Organic Matter In Polluted Sediments, Sami T. Abdel Bagi, Michael A. Kruge, Gary L. Salmon Jan 1996

Flash Pyrolysis Of Anthropogenic And Natural Organic Matter In Polluted Sediments, Sami T. Abdel Bagi, Michael A. Kruge, Gary L. Salmon

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

INTRODUCTION - Combustion products along with spilled petroleum and industrial chemicals contribute to environmental degradation by contaminating soils and sediments. Such anthropogenic organic matter (OM), if preserved in sediments, can serve an archival function, documenting the local, history of industrial pollution. Christensen and Zhang (1993) determined the sources of polycyclic aromatic hydrocarbons (P AH) to Lake Michigan from sedimentary records, finding that coal combustion was a major source for PAHs in these sediments. Bodzek and Luks-Betlej (1993) reported that atmospheric deposition is the main source of PAH in soils of the heavily industrialized Upper Silesia region of Poland. Smith and …

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Preparation Of Trifluoromethyl Lactol Derivatives Via Base Initiated Cyclobutanol Ring Opening To A Laterally Lithiated Trifluoromethyl Ketone, Daniel Becker, Daniel L. Flynn Jan 1996

Preparation Of Trifluoromethyl Lactol Derivatives Via Base Initiated Cyclobutanol Ring Opening To A Laterally Lithiated Trifluoromethyl Ketone, Daniel Becker, Daniel L. Flynn

Chemistry: Faculty Publications and Other Works

Benzocyclobutenone derivatives 4 are converted to the corresponding trifluoromethylcyclobutanols 5 by treatment with trifluoromethyltrimethylsilane in the presence of tetra-n-butylammonium fluoride. These trifluoromethylcyclobutanol derivatives are then treated with LiTMP in the presence of aromatic aldehydes to afford trifluoromethyllactols 6 via a laterally-lithiated trifluoromethylketone intermediate.

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Dynamic Phenomena In Organic Metal (Bedt-Ttf)3ta2f11, Juana Acrivos Jan 1996

Dynamic Phenomena In Organic Metal (Bedt-Ttf)3ta2f11, Juana Acrivos

Faculty Publications, Chemistry

Dynamic electron spin resonance, ESR measurements suggest that this paramagnetic, layered organic metal behaves similarly to cuprate superconductors. There is a dynamic equilibrium between doublet, D and triplet, T* states near the transition temperature to superconductivity Tc= 10±3 K; antiferromagnetic, AF resonance is observed from room temperature to ≈ 150 K, in this temperature region the temperature dependence of the D Lorentzian ESR line widths obtains a first order rate constant for the disappearance of the state (k1 = 3.5 ×107 e−111/T/s) and T* ESR is not observed, it is detected only below 44 K when the lifetime of AF …

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A New High Pressure Sapphire Nuclear Magnetic Resonance Cell, Shi Bai, Craig M. Taylor, Charles L. Mayne, Ronald J. Pugmire, David M. Grant Jan 1996

A New High Pressure Sapphire Nuclear Magnetic Resonance Cell, Shi Bai, Craig M. Taylor, Charles L. Mayne, Ronald J. Pugmire, David M. Grant

Faculty Publications

A new version of a single-crystal sapphire high pressure nuclear magnetic resonance (NMR) cell is described that is capable of controlling the sample pressure independent of the temperature. A movable piston inside the cell adjusts and controls the sample pressure from ambient conditions to 200 atm within plus or minus 0.3 atm. The linewidth at half-height for a 13C spectrum of carbon dioxide at 15degrees C and 57.8 atm is found to be 0.5 Hz. The carbon dioxide gas/liquid phase transition is clearly observed by measuring 13C chemical shifts as the sample pressure approaches equilibrium. The time required for this …

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Microhollow Cathode Discharges, K. H. Schoenbach, R. Verhappen, R. Tessnow, F. E. Peterkin, W. W. Byszewski Jan 1996

Microhollow Cathode Discharges, K. H. Schoenbach, R. Verhappen, R. Tessnow, F. E. Peterkin, W. W. Byszewski

Bioelectrics Publications

The current–voltage characteristics of hollow cathode discharges and their predischarges in argon under dc and pulsed conditions were found to have a positive slope at pressures up to approximately 50 Torr, and currents up to 20 mA, at a hole diameter of 0.7 mm. In this range of pressure and current, parallel operation of hollow cathode discharges, without ballast, was demonstrated. Scaling to higher pressure is possible by reducing the hole diameter. Pulsed experiments with an array of cathode rings of 75 μm diameter allowed us to obtain parallel operation of more than 50 discharges at a pressure of 350 …

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A Computational And Experimental Investigation Of The Pinacol Coupling And Rearrangement Reactions, Ryan Sullivan Jan 1996

A Computational And Experimental Investigation Of The Pinacol Coupling And Rearrangement Reactions, Ryan Sullivan

Honors Theses

This project was developed from previous reports concerned with the pinacol coupling and rearrangement methodologies. It is hoped that the results and conclusions of this study may provide someone in the future a chance to gain a more complete view of this material. Analysis of the pinacol coupling reaction shows that the yields of the pinacol products are not statistical for the asymmetric cycloalkanone systems. Also, the yields of the 5-7 and 6-7 systems plotted versus ab initio gas phase calculations of HOMG-LUMO gaps showed r values at or near 1.00. This correlation is excellent and offers an example of …

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Remote Marine Aerosol In The Gulf Of Maine: An Sem Study, Eric S. Gordon Jan 1996

Remote Marine Aerosol In The Gulf Of Maine: An Sem Study, Eric S. Gordon

Honors Theses

Eight aerosol samples were collected from a height of 34 meters atop Petit Manan Light located 16 miles East of Bar Harbor, Maine between July 25, 1995 and August 1, 1995. Both coarse and fine fractions were collected on 8.0 and 0.2 micron polycarbonate membrane filters, respectively. The sampling station consisted of a sampling box as well as a weather station (with various instruments) to record weather data for help in the analysis. The samples were analyzed using a scanning electron microscope and energy dispersive x-ray spectroscopy. Cluster analysis was perforned on the particles, grouping particles together with similar chemical …

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Determination Of Wavelength Dependent Quantum Yields For Iron (Iii) Photoreduction In Well Defined Chloride Media, J. Catherine Kneece Jan 1996

Determination Of Wavelength Dependent Quantum Yields For Iron (Iii) Photoreduction In Well Defined Chloride Media, J. Catherine Kneece

Honors Theses

The quantum yields for iron (lII) photoreduction in sodium chloride and sodium perchlorate media were measured as a function of wavelength. The experiments were conducted using natural levels of total iron, less than 300 nM. The results indicate that three species are photochemically active in these media, Fe(OH)+2, FeCl2+and FeCl2+. The quantum yields for (OH)+2 are 0.22 at 300 run and 0.076 at 340 nm. The quantum yields for FeCl+ are 0.048 at 300 run and 0.038 at 340 nm. The quantum yields for FeCl2+ are 0.088 at 300 nm and 0.051 at 340 nm. The data presented suggests that …

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Mile-A-Minute Weed, (Polygonum Perfoliatum L.), An Invasive Vine In Natural And Disturbed Sites, J. Douglas Oliver Jan 1996

Mile-A-Minute Weed, (Polygonum Perfoliatum L.), An Invasive Vine In Natural And Disturbed Sites, J. Douglas Oliver

Faculty Publications and Presentations

Polygonum perfoliatum L. (Polygonaceae) or mile-a-minute weed, from eastern Asia, has been spreading through wild and disturbed areas of the mid-Atlantic United States. It has a wide ecological amplitude and is found on stream banks, moist thickets, roadsides, nurseries, wood-piles, clearings, and ditches. Polygonum perfoliatum presents serious problems for reforestation because it thrives where forests are clear-cut. A southward direction of spread indicates that the species will probably proliferate in at least some southern states. Mechanical control is not likely to be completely effective because seeds are often left behind. No appropriate biocontrols are known. The plant poses a threat …

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Ohmic Drop Compensation In Voltammetry:  Iterative Correction Of The Applied Potential, David O. Wipf Jan 1996

Ohmic Drop Compensation In Voltammetry:  Iterative Correction Of The Applied Potential, David O. Wipf

CAS Publications

A new method of ohmic potential drop correction for use with potential step and sweep voltammetric methods is described. The method, iterative correction of the applied potential (ICAP), essentially replaces an electronic positive feedback correction with a digital positive feedback correction. This paper will present one form of the ICAP procedure, in which voltammetric current data acquired by a high-speed digital oscilloscope are used to iteratively generate a compensating potential waveform that is then synthesized by an arbitrary waveform generator. The ICAP method is advantageous for high-speed measurements, since many of the difficulties caused by electronic positive feedback compensation are …

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Segmental Motion Of Surface-Bound Swollen Poly(Methyl Acrylate)-D, Minghua Liang Jan 1996

Segmental Motion Of Surface-Bound Swollen Poly(Methyl Acrylate)-D, Minghua Liang

Masters Theses

"Poly (methyl acrylate)-da (PMA-da) was prepared and adsorbed on silica then swollen with toluene and carbon tetrachloride. Comparisons of deuterium NMR spin-lattice relaxation time, T1, and spin-spin relaxation time, T2, for the adsorbed polymer at different temperatures were made to obtain information about the backbone motion of the surface-bound polymer. The results suggest that the local fast motions may be similar to those in the corresponding solution, but the longer-range molecular motions were more restricted than those in solution. The log-normal distribution yielded mean correlation times which were 4-10 times slower for the …

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The Synthesis Of Azure B Derivatives: Potential Pro-Drugs For Photodynamic Therapy, Carla M. Edwards Jan 1996

The Synthesis Of Azure B Derivatives: Potential Pro-Drugs For Photodynamic Therapy, Carla M. Edwards

Dissertations

No abstract provided.

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