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Articles 31531 - 31560 of 34554

Full-Text Articles in Physical Sciences and Mathematics

Application Of The Batio3 Beam Fanning Limiter As An Adaptive Spatial Filter For Signal Enhancementin Pulsed Laser Excited Photothermal Spectroscopy, Stephen E. Bialkowski Jan 1989

Application Of The Batio3 Beam Fanning Limiter As An Adaptive Spatial Filter For Signal Enhancementin Pulsed Laser Excited Photothermal Spectroscopy, Stephen E. Bialkowski

Stephen E. Bialkowski

A method for obtaining a high-contrast visible-light signal from infrared absorption in low-absorbance samples is described. This method is based on a beam-fanning optical limiter in photorefractive BaTiO3. The resulting signal is not linear but does exhibit an enhanced signal-to-background ratio that is 4 to 6 orders of magnitude better than that of conventional infrared absorption spectrophotometry in the shot-noise limit. A simple model for the beam-fanning, optical-limiter-based, pulsed-laser-excited photothermal spectroscopy detector is found to describe the experimental data adequately. This technique using photothermal spectroscopy detection may have advantages for rapid signal analysis and for two-dimensional visible imaging …


Reactions Of Hydroxyl Radicals And Chlorine Atoms With Compounds Of Group Iv Elements., Denis J. O'Farrell Jan 1989

Reactions Of Hydroxyl Radicals And Chlorine Atoms With Compounds Of Group Iv Elements., Denis J. O'Farrell

Doctoral

Rate data are reported for the reaction of hydroxyl radicals with a series of substituted silanes. The data presented suggest the presence of polar effects in the transition state. Good agreement is reported between a relative rate study and an absolute rate study, Table (i). The corresponding reaction of chlorine atoms with the series of substituted silanes support the suggestion of polar effects in the transition state, Table (ii). Rate data are also reported for the reaction of hydroxyl radicals with a series of tetramethyl and tetraethyl compounds of the Group IV elements. The data presented show an enhanced reactivity …


Automated Data Acquisition For Analysis Of Fly Ash By Graphite Furnace Atomic Absorption Spectrophotometry, Eileen Dowds Jan 1989

Automated Data Acquisition For Analysis Of Fly Ash By Graphite Furnace Atomic Absorption Spectrophotometry, Eileen Dowds

Dissertations, Theses, and Masters Projects

No abstract provided.


A Kinetic Study Of The Oxidative Addition Of Simple Alkylvinyl Triflates To Tetrakis (Triphenylphosphine) Platinum(O), C. P. Desmond Longford Jan 1989

A Kinetic Study Of The Oxidative Addition Of Simple Alkylvinyl Triflates To Tetrakis (Triphenylphosphine) Platinum(O), C. P. Desmond Longford

Dissertations, Theses, and Masters Projects

No abstract provided.


Binding And Transport Properties Of Lithium In Red Cells From Hypertensive Patients And Normotensive Controls, Ravichandran Ramasamy Jan 1989

Binding And Transport Properties Of Lithium In Red Cells From Hypertensive Patients And Normotensive Controls, Ravichandran Ramasamy

Dissertations

No abstract provided.


Polymerization Of Methane, Ashok K. Sharma, H. Yasuda Jan 1989

Polymerization Of Methane, Ashok K. Sharma, H. Yasuda

Chemistry Faculty Research & Creative Works

Plasma polymerization of methane in a magnetically enhanced capacitively coupled bell jar reactor operating at a frequency of 10 kHz is reported. Dependence of polymer deposition rate on monomer feed rate (F), composite power parameter (W/FM), electrode temperature, and electrode cleanliness have been examined. Such functional properties as wettability, adhesion, and thermal stability of the polymer are found to depend on the composite power parameter (W/FM) of the plasma. The permeability studies indicate highly crosslinked nature of the polymer. ESCA studies reveal code position of electrode material with the polymer under high W/FM conditions, potential applications of plasma polymer of …


Permanganate Colorimetric Rapid Method For Chemical Oxygen Demand In Seawater, Myung Zoon Czae, Taekee Hong, Myung Hoon Kim Jan 1989

Permanganate Colorimetric Rapid Method For Chemical Oxygen Demand In Seawater, Myung Zoon Czae, Taekee Hong, Myung Hoon Kim

Chemistry & Biochemistry Faculty Publications

No abstract provided.


Synthesis And Nucleophilic Reactions Of Bifunctional Thiourea S,S,S-Trioxides, Dan Webb '89 Jan 1989

Synthesis And Nucleophilic Reactions Of Bifunctional Thiourea S,S,S-Trioxides, Dan Webb '89

Honors Projects

The synthesis of bifunctional thioureas and the corresponding thiourea S,S,S-trioxides has been examined. Two methods for the synthesis of the bisthioureas were employed. One involved the treatment of a diamine with silicon tetraisothiocyanate in benzene. The second involved treatment of the amine with ammonium thiocyanate in dilute acid. This latter synthesis was superior because of the ease of its use, the high yields obtained, and the purity of the products. Though this synthesis worked well for the preparation of phenylene-l,4-bis(thiourea), it yielded only bisthiocyanate salts in the synthesis of aliphatic thioureas. The oxidation of the bisthioureas was carried out using …


Dynamics Of Triplet States In Organic Conductors By Esr Measurements, Juana Acrivos, M. Chen Lei Jan 1989

Dynamics Of Triplet States In Organic Conductors By Esr Measurements, Juana Acrivos, M. Chen Lei

Faculty Publications, Chemistry

No abstract provided.


Nonadditive Effects In Hf And Hcl Trimers, G. Chalasinski, S. M. Cybulski, M. M. Szczesniak, Steve Scheiner Jan 1989

Nonadditive Effects In Hf And Hcl Trimers, G. Chalasinski, S. M. Cybulski, M. M. Szczesniak, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Nonadditive effects are calculated for (HF)3 and (HCl)3 complexes and analyzed via the combination of perturbation theory of intermolecular forces with Møller–Plesset perturbation theory (MPPT). In both systems the nonadditivity is dominated by the self‐consistent field (SCF) deformation effect, i.e., mutual polarization of the monomer wavefunctions. Heitler–London exchange and correlation effects are of secondary importance. Three‐body terms exhibit much lesser basis set dependence than the two‐body effects and even quite moderate basis sets which are not accurate enough for treatment of two‐body forces can yield three‐body effects of quantitative quality. This is due in large measure to the …


Analysis Of The Potential Energy Surface Of Ar–Nh3, G. Chalasinski, S. M. Cybulski, M. M. Szczesniak, Steve Scheiner Jan 1989

Analysis Of The Potential Energy Surface Of Ar–Nh3, G. Chalasinski, S. M. Cybulski, M. M. Szczesniak, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The combination of supermolecular Møller–Plesset treatment with the perturbation theory of intermolecular forces is applied in the analysis of the potential energy surface of Ar–NH3. Anisotropy of the self‐consistent field (SCF) potential is determined by the first‐order exchange repulsion. Second‐order dispersion energy, the dominating attractive contribution, is anisotropic in the reciprocal sense to the first‐order exchange, i.e., minima in one nearly coincide with maxima in the other. The estimated second‐order correlation correction to the exchange effect is nearly as large as a half ΔESCF in the minimum and has a ‘‘smoothing’’ effect on the anisotropy of …


Choosing A Calcium Supplement For Sheep Fed Cereal Grains, R L. Peet, Michael Hare Jan 1989

Choosing A Calcium Supplement For Sheep Fed Cereal Grains, R L. Peet, Michael Hare

Journal of the Department of Agriculture, Western Australia, Series 4

Sheep fed cereal grains as an energy source over summer usually need added calcium because cereal grains are generally low in calcium (for example, 0.03 per cent calcium compared to 0.26 per cent phosphorus), and there may not be a natural source such as clover, weeds, leafy stubble or edible bush in the paddock.

The safestt and most effective calcium supplement is finely ground limestone added to the feed, but some farmers have used other sources of calcium such as gypsum and superphosphate in this manner.


Intensive Animal Industries In The Peel-Harvey Catchment, R W. Payne Jan 1989

Intensive Animal Industries In The Peel-Harvey Catchment, R W. Payne

Journal of the Department of Agriculture, Western Australia, Series 4

The Swan coastal plain to the north and south of Perth is attractive for the intensive production of pigs and poultry for several reasons. It is close to markets, feed manufacturers and labour; has a less extreme climate than inland areas; and is underlain by a large reserve of high quality groundwater.

Because these are all intensive operations, large quantaties of nutrient-rich waste are produced over a very small area. They can severely damage ground and surface waters unless steps are taken to control the wastes which they produce.

This article oulines both the nature of intensive aniamal industries in …


Utilization Of A Helium Discharge Detector For Quantitation Of Organohalogen Compounds, David Andrew Ryan Jan 1989

Utilization Of A Helium Discharge Detector For Quantitation Of Organohalogen Compounds, David Andrew Ryan

Dissertations, Theses, and Masters Projects

No abstract provided.


Synthesis And Characterization Of 3-Alkylidenetetrahydrofurans, Kevin Patrick Dockery Jan 1989

Synthesis And Characterization Of 3-Alkylidenetetrahydrofurans, Kevin Patrick Dockery

Dissertations, Theses, and Masters Projects

No abstract provided.


Dielectric And Kinetic Analysis Of Thermosetting Polyester Resin, Patricia Haverty Tully Jan 1989

Dielectric And Kinetic Analysis Of Thermosetting Polyester Resin, Patricia Haverty Tully

Dissertations, Theses, and Masters Projects

No abstract provided.


Non-Lattice Monte Carlo Simulations Of Polymer Motion, David Albert Eichinger Jan 1989

Non-Lattice Monte Carlo Simulations Of Polymer Motion, David Albert Eichinger

Dissertations, Theses, and Masters Projects

No abstract provided.


The Synthesis And Photochemistry Of Anthraquinone-2,6-Disulfonyl-Beta-Cyclodextrin, Angela Marie Aquino Jan 1989

The Synthesis And Photochemistry Of Anthraquinone-2,6-Disulfonyl-Beta-Cyclodextrin, Angela Marie Aquino

Dissertations, Theses, and Masters Projects

No abstract provided.


Monitoring Environmental Effects On High Performance Tetraglycidyl Methylenedianiline Epoxy And Pmr-15 Polyimide, William Robinson Hayes Clark Jan 1989

Monitoring Environmental Effects On High Performance Tetraglycidyl Methylenedianiline Epoxy And Pmr-15 Polyimide, William Robinson Hayes Clark

Dissertations, Theses, and Masters Projects

No abstract provided.


Residual Influence Of Macronutrient Enrichment On The Aquatic Food Web Of An Okefenokee Swamp Abandoned Bird Rookery, J. Douglas Oliver, Steven A. Schoenberg Jan 1989

Residual Influence Of Macronutrient Enrichment On The Aquatic Food Web Of An Okefenokee Swamp Abandoned Bird Rookery, J. Douglas Oliver, Steven A. Schoenberg

Faculty Publications and Presentations

We present evidence for residual nutrient enrichment of diverse components of a blackwater marsh, by a biotic component of the ecosystem itself. Thousands of nesting white ibis (Eudocimus albus) that foraged over a 20-km radius fertilized a rookery with guano within Okefenokee Swamp. Georgia. USA. One to two yr after the birds abandoned it. this marsh showed continued enrichment effects. Elevated available phosphorus in sediments, as measured by equilibrium phosphate concentration, contributed to enhanced biomass of phytoplankton in the overlying water column. Planktivorous fish were greater in biomass than at reference sites. Experimental phosphorus and nitrogen fertilization of enclosures at …


A Spectroscopic Study Of Charge Distribution In Transition Metal Bridging Hydride Complexes, Shixiong Chen Jan 1989

A Spectroscopic Study Of Charge Distribution In Transition Metal Bridging Hydride Complexes, Shixiong Chen

Masters Theses

A series of transition metal bridging hydrides of general formula C[μ-HM2(CO)10] (C = tetraethylammonium, Et4N+; tetraphenylphosphonium, Ph4P+; of bis(triphenylphosphine)iminium, PPN+; M = Cr or W) were synthesized from M(CO)6 and NaBH4 bt known methods. As a means of obtaining information about the charge distribution in these complexes, they were allowed to interact in solution and the solid state with triphenylphosphine oxide (TPPO) on the premise that this electron donor could identify sites of relative electron deficiency. Evidence for interaction was sought via solution and …


Derivatization Of Coal By Alkylation And Lithium Iodide Treatment, Cynthia L. Ludwig Jan 1989

Derivatization Of Coal By Alkylation And Lithium Iodide Treatment, Cynthia L. Ludwig

Masters Theses

The hypothesis that hydrogen-bonded ethers in coal could be cleaved by reaction with lithium iodide in pyridine to form new phenol groups was investigated for coals #2, 3, and 5 plus their alkylated derivatives from the Argonne Premium Coal Sample Program. Changes caused by alkylation and reaction with LiI were monitored by solvent extraction yeilds, solvent swelling, FT-IR and Size Exclusion Chromatography (SEC).

Solubilities of alkylated coals are rank and oxygen functionality dependent. Evidence supports the hypothesis that the solubilization mechanism is dependent on the extent of hydrogen-bonding in the coal. Elimination of hydrogen-bonds through alkylation increases toluene solubility and …


A Novel Synthesis Of Cyclic And Acyclic 3-Alkenoic Acids Via Ionization/Elimination Of Β-Lactones, Stephen Lucas Maluleka Jan 1989

A Novel Synthesis Of Cyclic And Acyclic 3-Alkenoic Acids Via Ionization/Elimination Of Β-Lactones, Stephen Lucas Maluleka

Masters Theses

Exposure of spiro β-lactones and 3-substituted 4,4-dialkyl oxetan-2-ones to magnesium bromide in diethyl ether solvent resulted in the smooth generation of β,γ-unsaturated acid derivatives in high yield and isomeric purity. It is believed that this reaction occurs via the formation of a stable tertiary carbocation at the β-carbon resulting from cleavage of the carbon-oxygen sigma bond due to the complexation of magnesium cation with the ring oxygen atom. Rapid loss of an adjacent proton then furnishes the unsaturated acids. The β-lactone precursors were prepared by the dehydration of β-hydroxy acid derivatives (obtained from the condensation of ketones with acetic acid …


Theoretical Studies Of The Energies And Geometries Of Strained Hydrocarbons, Mitchell Alan Miller Jan 1989

Theoretical Studies Of The Energies And Geometries Of Strained Hydrocarbons, Mitchell Alan Miller

Dissertations, Theses, and Capstone Projects

Theoretical models are used to explore problems of interest to organic chemists in four projects. The first three apply existing methodologies to investigate a series of strained cyclic hydrocarbon molecules; the fourth develops methodology.

Project I. Semiempirical calculations have been performed on a variety of hydrocarbons composed of fused cyclobutane rings using the MNDO, AM1 and MM2 methods. The systems studied include linearly concatenated cyclobutanes (ladderanes), cyclic structures (prismanes) and two 'star-shaped' C24H24 hydrocarbons, helvetane and israelane. The results reported include optimized geometries, heats of formation and vibrational frequencies. The performance of the theoretical models is evaluated …


Chemical Modification Of Skeletal Muscle Sarcoplasmic Reticulum Vesicles: A Study Of Calcium Permeability, Janice F. Stuart Jan 1989

Chemical Modification Of Skeletal Muscle Sarcoplasmic Reticulum Vesicles: A Study Of Calcium Permeability, Janice F. Stuart

Dissertations and Theses

Skeletal muscle contains an internal membrane system called the sarcoplasmic reticulum (SR) whose function is to regulate the Ca2+ concentration of the myoplasm. Ca2+ is transported into the SR from the myoplasm via a Ca2+ dependent ATPase thus lowering the myoplasmic Ca2+ concentration. Ca2+ exits from the SR via a Ca2+ releqse pathway resultingin the increase of myoplasmic Ca2+. Muscles contract when the myoplasmic Ca2+ concentration is > 5 uM and relax when the Ca2+ concentration is lowered below 1 uM. The Ca2+ dependent ATPase has been extensively studied but …


Pcb Congener Analysis With Hall Electrolytic Conductivity Detection, Robert D. Edstrom Jan 1989

Pcb Congener Analysis With Hall Electrolytic Conductivity Detection, Robert D. Edstrom

Dissertations, Theses, and Masters Projects

This work reports the development of an analytical methodology for the analysis of PCB congeners based on integrating relative retention data provided by other researchers. The retention data were transposed into a multiple retention marker system which provided good precision in the calculation of relative retention indices for PCB congener analysis. Analytical run times for the developed methodology were approximately one hour using a commercially available GC capillary column. A Tracor Model 700A Hall Electrolytic Conductivity Detector (HECD) was employed in the GC detection of Aroclor standards and environmental samples. Responses by the HECD provided good sensitivity and were reasonably …


Dielectric Monitoring Of Environmental Effects On The Cure Of Epoxy-Polyamide Coatings, Thomas Hamilton Jan 1989

Dielectric Monitoring Of Environmental Effects On The Cure Of Epoxy-Polyamide Coatings, Thomas Hamilton

Dissertations, Theses, and Masters Projects

No abstract provided.


Quantitative Footprinting Analysis Using A Dna-Cleaving Metalloporphyrin Complex+, James C. Dabrowiak, Brian Ward, Jerry Goodisman Dec 1988

Quantitative Footprinting Analysis Using A Dna-Cleaving Metalloporphyrin Complex+, James C. Dabrowiak, Brian Ward, Jerry Goodisman

Chemistry - All Scholarship

The results of quantitative footprinting studies involving the antiviral agent netropsin and a DNA-cleaving cationic metalloporphyrin complex are presented. An analysis of the footprinting autoradiographic spot intensities using a model previously applied to footprinting studies involving the enzyme DNase I [Ward, B., Rehfuss, R., Goodisman, J., & Dabrowiak, J. C. (1988) Biochemistry 27, 1198-12051 led to very low values for netropsin binding constants on a restriction fragment from pBR-322 DNA. In this work, we show that, because the porphyrin binds with high specificity to DNA, it does not report site loading information in the same manner as does DNase I. …


The Effect Of Solvent Type On The Infrared Spectrum Of Carbon Monoxide Adsorbed At Platinum Electrodes, Mark Anderson, Daniel Blackwood, Thomas Richmond, Stanley Pons Dec 1988

The Effect Of Solvent Type On The Infrared Spectrum Of Carbon Monoxide Adsorbed At Platinum Electrodes, Mark Anderson, Daniel Blackwood, Thomas Richmond, Stanley Pons

Mark R. Anderson

The infrared spectrum of CO adsorbed on a platinum electrode from several solvents was investigated. In N-methylformamide, acetonitrile, and 1,2-dichloroethane, the infrared band attributed to linearly bonded CO had experimental Stark tuning rates of 20 cm−1/V, 22 cm−1/V, and 19 cm−1/V, respectively. For each of these solvents, the potential dependence of the band position was found to be linear for the entire potential range investigated. When methanol was the solvent, the plot of the band position versus potential had three distinctly linear portions, each with a different value for the slope. The behavior is explained in terms of the ability …


The Behavior Of The Infrared Spectrum Of Carbon Monoxide Adsorbed At Platinum Electrodes From Non-Aqueous Solvents, Mark Anderson, Daniel Blackwood, Stanley Pons Dec 1988

The Behavior Of The Infrared Spectrum Of Carbon Monoxide Adsorbed At Platinum Electrodes From Non-Aqueous Solvents, Mark Anderson, Daniel Blackwood, Stanley Pons

Mark R. Anderson

Electrochemical oxidation of vanadium hexacarbonyl anion, V(Co)6 in aprotic solvents results in formation of the V(0) complex which decomposes to form CO in high concentrations next to the electrode surface. As a result, CO is more rapidly adsorbed on the surface than by conventional methods. Surface reflection infrared spectroscopy shows that the potential dependent frequency shift for the infrared active bands due to CO adsorbed on platinum is 19 cm−1/V in 1,2-dichloroethane and 22 cm−1/V in acetonitrile, which are considerably less than the 30 cm−1/V observed in aqueous systems.