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Articles 2521 - 2550 of 2576

Full-Text Articles in Analytical Chemistry

The Purification And Partial Characterization Of The Surface Polysaccharides From Three Fast-Growing Rhizobium Japonicum Strains, Madhav P. Yadav Jan 1984

The Purification And Partial Characterization Of The Surface Polysaccharides From Three Fast-Growing Rhizobium Japonicum Strains, Madhav P. Yadav

Masters Theses

The fast-growing strains of R. japonicum were originally isolated from China. They are acid-producing Rhizobia and are capable of nodulating soybeans. These isolates share a common host-specificity (Peking soybean) with the slow-growing R. japonicum strains even though their biochemical properties are more closely related to other fast-growing Rhizobium species. The surface polysaccharides from three fast-growing R. japonicum strains--USDA201, USDA205, and HC205--were isolated and partially characterized. Strain HC205 is a nod⁻ mutant of USDA205 which lacks the symbiotic plasmid. These surface polysaccharides consist of extracellular, capsular and lipopolysaccharides (EPSs, CPSs and LPSs). The EPSs from all three strains are very similar …


A Microprocessor Controlled Pulsed Hollow Cathode Lamp For An Atomic Absorption Spectrometer, James B. Schilling Aug 1983

A Microprocessor Controlled Pulsed Hollow Cathode Lamp For An Atomic Absorption Spectrometer, James B. Schilling

Masters Theses

A Jarrell-Ash Atomic Absorption/Flame Emission 82-360 Spectrometer was interfaced to a Heathkit ETA-3400 microprocessor. The microprocessor is used to pulse the hollow cathode lamp from a "steady" current to a "peak " current during the opening of the chopper. The current from the photomultiplier-tube is converted to a proportional voltage which is supplied to a sample-and-hold circuit. A successive approximation routine is used to convert the voltage to a representative digital value. Digital values are obtained for the "blank" and "sample" and are used to calculate percent absorption values. The system can also be used to obtain emission values.

The …


Generalized Response Of Chemiluminescence Analyzers, A. A. Mehrabzadeh, Robert J. O'Brien, Thomas M. Hard Aug 1983

Generalized Response Of Chemiluminescence Analyzers, A. A. Mehrabzadeh, Robert J. O'Brien, Thomas M. Hard

Chemistry Faculty Publications and Presentations

The mass flow and chemical kinetic equations for a gaseous chemiluminescence (CL) analyzer are formulated and solved. The resultant equation can be used to predict the absolute response of the analyzer as a function of the sample flow rate, the sample gas pressure, the chamber pressure, the chamber volume, the mass flow rate and mole fraction of the reagent gas, and the rate constants of the relevant chemical processes. Thus, the equation allows optimization of these parameters. It is shown that for varying sample pressure the analyzer can be used to measure either concentration or mole fraction and that interfering …


A Study Of Temperature Dependent Electrical Properties Of Ion-Implanted Gallium Arsenide, Shanmugam Sundaram May 1983

A Study Of Temperature Dependent Electrical Properties Of Ion-Implanted Gallium Arsenide, Shanmugam Sundaram

Master's Essays (1922 - )

Two samples, GaAs:Mg (p-type) and GaAs:Si (n-type), ion-implanted to the same does of 5x1012 ions/cm2. were investigated to study their temperature dependent electrical properties. The resistivities and Hall constant were determined directly by Van der Pauw Technique. Sheet carrier concentration and carries mobility were then calculated. The Silicon sample, in which the properties were relatively temperature independent, was found to be in the metallic conduction range. Hence the magnesium sample was chosen for further temperature dependency investigation.


Internal Rotation Effects And Nuclear Hyperfine Structure In The Microwave Spectrum Of Propyne-Hf, Roger E. Bumgarner Jan 1983

Internal Rotation Effects And Nuclear Hyperfine Structure In The Microwave Spectrum Of Propyne-Hf, Roger E. Bumgarner

Masters Theses

The microwave spectrum of the weakly bound propyne-HF/DF complex in the region between 6 and 16 GHz was analyzed. The spectrum was characteristic of a distorted T-shaped asymmetric top exhibiting torsional splitting caused by a low barrier to internal rotation of the methyl top relative to the propyne-HF frame. Deuterium substitution of HF confirms that the acid proton of HF is located between the F atom and the propyne triple bond. The spectroscopic constants given below are consistent with the fluorine atom being displaced toward the methyl group from a line perpendicular to and bisecting the propyne triple bond, suggesting …


Kinetic And Spectral Studies Of Cobalt (Ii) -4, 4’, 4’’, 4’’’ –Tetrasulfophthalocyanine With Sodium Cyanide In Aqueous Solution, Pablo J. Diaz Cruz Dec 1982

Kinetic And Spectral Studies Of Cobalt (Ii) -4, 4’, 4’’, 4’’’ –Tetrasulfophthalocyanine With Sodium Cyanide In Aqueous Solution, Pablo J. Diaz Cruz

Masters Theses & Specialist Projects

Kinetic studies of the cobalt (II)-4, 4’, 4’’, 4’’’-tetrasulfophtalocyanine and cyanide system were performed under argon and in air over temperature ranges of 294-314°K and 294-324°K, respectively. Two reactions were detected under argon. One was quite rapid and was followed on the stopped-flow apparatus. The results are consistent with the perturbation of a monomer-dimer equilibrium. The second reaction was slow enough to be followed spectrophotometrically on the Cary Model 14 spectrophotometer. The second order rate constant of 0.11 M-1 sec-1 at 294°K has been attributed to the rate of substitution of the second cyanide addition to a dye-cyanide …


Determination Of Organophosphorus Compounds By Hplc With Post-Column Photochemical Degradation Followed By The Formation Of Reduced Heieropolymolybdate, Stephen R. Priebe Dec 1982

Determination Of Organophosphorus Compounds By Hplc With Post-Column Photochemical Degradation Followed By The Formation Of Reduced Heieropolymolybdate, Stephen R. Priebe

Dissertations

A novel method for the determination of organophosphorus (OP) compounds by HPLC with post-column photochemical and chemical derivatization reactions has been developed. The OP compounds eluted from the column were photochemically degraded to orthophosphate by the use of a 450 W xenon lamp in conjunction with an auxiliary photodegradation reagent. The photodegradation reaction was studied extensively by means of batch irradiations with triethylphosphate as a model compound. The effects of the initial concentrations of triethylphosphate and ammonium peroxydisulfate, and of varying the pH of the reaction medium were determined. A survey of potential interferences was performed. Copper(II) ion was found …


The Use Of Thermal Analysis In The Identification And Characterization Of Fibers Of Forensic Interest, Ronald J. Coffey May 1980

The Use Of Thermal Analysis In The Identification And Characterization Of Fibers Of Forensic Interest, Ronald J. Coffey

All-Inclusive List of Electronic Theses and Dissertations

This study investigates the use of thermal analysis for the identification and characterization of fibers for forensic purposes. Fibers such as polyesters, polyacrylics, polypropylenes and nylon were investigated by Differential Thermal Analysis (D.T.A.) and Thermogravimetric Analysis (T.G.A.) to see if their resulting thermograms were characteristic of each fiber. Also, infrared analysis was performed on each fiber. In addition, such factors as heating rate and sample size along with fiber blends were studied as to their effect on thermograms. As a result of this study several important conclusions may be drawn. Although it was found that for the most part D.T.A. …


A Column For The High Pressure Liquid Chromatography Of Some Potentially Hazardous Metal Ions, Stephen R. Friebe Apr 1980

A Column For The High Pressure Liquid Chromatography Of Some Potentially Hazardous Metal Ions, Stephen R. Friebe

Masters Theses

No abstract provided.


Gas Phase Hydrogen Permeation In Alpha Titanium And Carbon Steels, Donald L. Johnson, Kiritkumar K. Shah, Bruce H. Reeves, Vijay L. Gadgeel Jan 1980

Gas Phase Hydrogen Permeation In Alpha Titanium And Carbon Steels, Donald L. Johnson, Kiritkumar K. Shah, Bruce H. Reeves, Vijay L. Gadgeel

Department of Chemistry: Faculty Publications

Commercially pure titanium rods were machined into hollow cylinders and gas-phase permeation and diffusion measurements obtained with a quadrupole residual gas analyzer at temperatures between 400-800°C and pressures between 0.533 and 266.6 Nrn-2. Pressure dependence measurements established that phase boundary reactions as well as lattice diffusion control the transport process. Lag-time data yield excellent agreement with the diffusivity data of Wasilewski and Kehl and Papazoglou and Hepworth for the case where phase boundary reactions are taken into account. The best value of the diffusivity is D = 2.1 x 10-2 exp (-50,40O/RT). Analysis of lag-time data reveals …


Analysis Of Mixtures Of Chlorine, Chlorine Dioxide And Chlorite, Ying-Chien Chu Dec 1979

Analysis Of Mixtures Of Chlorine, Chlorine Dioxide And Chlorite, Ying-Chien Chu

Masters Theses

No abstract provided.


Photon Counting System For The Determination Of Creatine Phosphokinase, Steven E. Dueball Apr 1979

Photon Counting System For The Determination Of Creatine Phosphokinase, Steven E. Dueball

Masters Theses

No abstract provided.


The Analysis Of N-Methylscopolamine Bromide By High Speed Ion Pair Partition Chromatography, John L. Nappier Aug 1978

The Analysis Of N-Methylscopolamine Bromide By High Speed Ion Pair Partition Chromatography, John L. Nappier

Masters Theses

No abstract provided.


The Response Of The Micro-Adsorption Detector To Inorganic Anions, Maria E. Munera Aug 1978

The Response Of The Micro-Adsorption Detector To Inorganic Anions, Maria E. Munera

Masters Theses

No abstract provided.


Biological And Chemical Evaluation Of The Aquatic Environment Of Selected Undeveloped Kentucky Lake Embayments, Marshall Gordon, Morgan E. Sisk Dec 1976

Biological And Chemical Evaluation Of The Aquatic Environment Of Selected Undeveloped Kentucky Lake Embayments, Marshall Gordon, Morgan E. Sisk

KWRRI Research Reports

This report describes research involving biological and chemical analysis of two undeveloped embayments on Kentucky Lake, namely Anderson and Vickers Bays. Field and laboratory studies were made to assess current biotic standing crops, limnological conditions, levels of inorganic and organic pollutants in the embayments.


Spectroscopic Studies Of The Hydrogen-Chlorine Flame, Gonzalo Pizarro Aug 1975

Spectroscopic Studies Of The Hydrogen-Chlorine Flame, Gonzalo Pizarro

Masters Theses

No abstract provided.


The Development Of An Arsenic(V) Selective Electrode, Sandra Gee Kang Nov 1974

The Development Of An Arsenic(V) Selective Electrode, Sandra Gee Kang

Dissertations and Theses

The object of this research was to develop an arsenic(V) selective electrode. The electrode is based on a solid state membrane prepared by pressing a precipitate of silver arsenate-silver sulfide into a pellet. After the electrode was made, experiments were designed to check for three general characteristics of the electrodes: dependence of potential on pH for constant arsenic(V) concentration; dependence of potential on arsenic(V) concentrations at constant pH and extent of interference due to phosphate and arsenic(III) ions. From these measurements, it was found that Ag2HAs04 was formed originally in the membranes containing a small fraction of …


A Systematic Approach To Organic Qualitative Analysis Using Mass And Nuclear Magnetic Resonance Spectroscopy, Duane R. Greenly Jan 1974

A Systematic Approach To Organic Qualitative Analysis Using Mass And Nuclear Magnetic Resonance Spectroscopy, Duane R. Greenly

Morehead State Theses and Dissertations

A thesis presented to the faculty of the School of Science and Mathematics at Morehead State University in partial fulfillment of the requirement for the Degree of Master of Science by Duane R. Greenly on January 14, 1974.


Preparation And Characterization Of The Addition Compounds Formed By Trifluoromethylsulfur Trifluoride With The Lewis Acids Pf5, Bf3, Asf5, And Sbf5, Maria Kramar Jan 1973

Preparation And Characterization Of The Addition Compounds Formed By Trifluoromethylsulfur Trifluoride With The Lewis Acids Pf5, Bf3, Asf5, And Sbf5, Maria Kramar

All Master's Theses

Addition compounds of the monosubstituted derivative of sulfur tetrafluoride, trifluormethlysulfur trifluoride with the Lewis acids PF5, BF3, AsF5, and SbF5 were prepared, isolated and characterized. On the basis of their infrared spectra, it is suggested that these new compounds can be classified as types of fluoronium adducts and that their ionic formulation can be expressed as CF3SF2+MF-n+1 where MFn represents the acceptor used. Upon oxidative hydrolysis of trifluoromethylsulfur trifluoride, trifluormethlsulfonic acid was prepared. Further investigations included the preparation and isolation of perfluoroethysulfur trifluoride and its addition …


Kinetics Of The Formation Of Nickel(Ii) Complexes With N,N’-Dibenzylethylenediamine And N,N’-Bis(2-Picolyl)Ethylenediamine, Zahid Amjad Aug 1972

Kinetics Of The Formation Of Nickel(Ii) Complexes With N,N’-Dibenzylethylenediamine And N,N’-Bis(2-Picolyl)Ethylenediamine, Zahid Amjad

Masters Theses

No abstract provided.


Relation Of Aromatic Substitution Patterns To Nmr Shifts Produced Tris - (1,1,1,2,2,3,3 - Heptafluoro - 7,7, Dimethyl - 4,6 - Octanedione) Europium (Iii), Roy R. Reeves Jul 1972

Relation Of Aromatic Substitution Patterns To Nmr Shifts Produced Tris - (1,1,1,2,2,3,3 - Heptafluoro - 7,7, Dimethyl - 4,6 - Octanedione) Europium (Iii), Roy R. Reeves

Morehead State Theses and Dissertations

A thesis presented to the faculty of the School of Sciences and Mathematics at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Chemistry by Roy R. Reeves on July 27, 1972.


Relation Of Shift Magnitude Of Alkyl Substituents To Aromatic Substitution Patterns, Michael E. Evans Jul 1972

Relation Of Shift Magnitude Of Alkyl Substituents To Aromatic Substitution Patterns, Michael E. Evans

Morehead State Theses and Dissertations

A thesis presented to the faculty of the School of Science and Mathematics at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Michael E. Evans on July 27, 1972.


19f Nmr And Bx3 Complexes, Nancy Toole Tucker Apr 1972

19f Nmr And Bx3 Complexes, Nancy Toole Tucker

Morehead State Theses and Dissertations

A thesis presented to the faculty of the School of Sciences and Mathematics at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Chemistry by Nancy Toole Tucker on April 21, 1972.


Reaction Of Aqueous Catechol Solutions With Minerals, Boonthong Poocharoen Jan 1972

Reaction Of Aqueous Catechol Solutions With Minerals, Boonthong Poocharoen

Dissertations and Theses

The effectiveness of catechol, an aromatic vic-diol, in dissolving silicate minerals was studied. A synthetic amorphous magnesium trisilicate, Mg₂Si₃O₈∙5H₂O, as well as the minerals olivine, sepiolite, diopside, augite, and enstatite were used to react with catechol in slightly acidic, basic, and neutral solutions. It was found, depending on the solvent used, that 33-52, 8-17, 14-30, 5-11, 3-6, and 0.5-1 % of the minerals dissolved, respectively.

The reaction with Mg₂Si₃0₈·5H₂0 resulted in the formation of crystals of magnesium tris (catecholato) siliconate nonahydrate Mg[Si(Cat)₃]∙9H₂0. Dehydration of the crystals at room temperature resulted in the loss of 6 moles of water to form …


The Response Of The Micro-Adsorption Detector To Inorganic Cations, David P. Mckay Aug 1971

The Response Of The Micro-Adsorption Detector To Inorganic Cations, David P. Mckay

Masters Theses

No abstract provided.


A Kinetic Analysis Of The Iodination Of Pyruvic Acid And Pyruvate Esters, Mohamed M. Fahmi Hegazi Aug 1971

A Kinetic Analysis Of The Iodination Of Pyruvic Acid And Pyruvate Esters, Mohamed M. Fahmi Hegazi

All Master's Theses

In the present work the relative rates of iodination of pyruvic acid and ethyl and methyl pyruvate have been compared at 25.0° C. These studies allow the determination of the respective free energies of activation for these processes. Measurements have also been carried out at various temperatures to determine the enthalpies and entropies of activation for the spontaneous and base catalysed iodinations of these pyruvate systems. The present thesis also includes a comparison of the solvent deuterium isotope effects associated with the spontaneous rate of iodination of pyruvic acid and the alkyl pyruvates. Also, the catalytic rate coefficients associated with …


A Study Of The Mechanism Of The Ligand Exchange Between Triethilenetetraminenickel(Ii) And 1,10-Phenanthroline, James Allan Boersma Apr 1971

A Study Of The Mechanism Of The Ligand Exchange Between Triethilenetetraminenickel(Ii) And 1,10-Phenanthroline, James Allan Boersma

Dissertations

No abstract provided.


The Design, Construction, And Application Of A Multibeam Fiber Optics Photometric Titrator, Marlin George Bensinger Aug 1970

The Design, Construction, And Application Of A Multibeam Fiber Optics Photometric Titrator, Marlin George Bensinger

Masters Theses

No abstract provided.


The Stepwise Nature Of The Unwrapping And Transfer Of Ethylenediaminediacetate From Nickel(Ii) To Copper(Ii), Robert Swann Apr 1970

The Stepwise Nature Of The Unwrapping And Transfer Of Ethylenediaminediacetate From Nickel(Ii) To Copper(Ii), Robert Swann

Masters Theses

No abstract provided.


Acid-Base Catalysis Of The Enolization Of Acetone, Janet Louise Larson Jan 1970

Acid-Base Catalysis Of The Enolization Of Acetone, Janet Louise Larson

Undergraduate Honors Theses

Measurements are reported on the rate of iodination of acetone at 25°c in arsenate, phosphate, and diethylmalonic acid buffers at a constant ionic strength of 0.2. Unlike earlier results which indicate that in acetic acid buffer the expression for the reaction velocity contains an appreciable kinetic term involving the product of the concentrations of acid and anion, it has been found from the present work that such a term is experimentally immeasurable for the above mentioned buffers. This finding coupled with the relatively powerful catalysis by the phosphate and arsenate dianions could imply the simultaneous participation of these species in …