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1997

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Articles 2221 - 2250 of 2472

Full-Text Articles in Physical Sciences and Mathematics

A Chemical Extraction Study Of Lead Contaminated Soil From Granite City, Il, Yan Zhang Jan 1997

A Chemical Extraction Study Of Lead Contaminated Soil From Granite City, Il, Yan Zhang

Masters Theses

Granite City, IL, surface soil ( 0-10 cm ) contaminated with lead was studied by both single- and a four-step sequential chemical extraction procedures designed to establish the partitioning, mobility and availability of lead in soil. The five fractions corresponding to the selected extractants were exchangeable, carbonates-bound, Fe-Mn oxides bound, organic matter and residual. Lead contamination of the soil was determined as a function of particle size and soil depth.

The contaminated sample had the highest lead content of 573.1 mg/kg at the 4 cm soil depth level, and on average was about 8.8 times that of background soil. Most …


Constancy Of Bond Dissociation Energy Ratios For Ab₂/Ab Systems, Danyu Xu Jan 1997

Constancy Of Bond Dissociation Energy Ratios For Ab₂/Ab Systems, Danyu Xu

Masters Theses

G2 and G2(MP2) theories have been used to study the bond dissociation energies D0m of a series of AB2, AB2+, AB2-, AB, AB+ and AB- systems. A total of fifty-four molecules and ions have been examined, for which B = O, S or Se and A = C, S, Ge, N+, P+, As+, B-, Al- or Ga-. Each triatomic system has sixteen valence electrons and each diatomic system has ten valence electrons. Both triplet and singlet spin …


An Expeditious Synthesis Of Β,Γ-Unsaturated Δ-Lactones: Useful Pharmacological Synthetic Intermediates, Li Xiong Jan 1997

An Expeditious Synthesis Of Β,Γ-Unsaturated Δ-Lactones: Useful Pharmacological Synthetic Intermediates, Li Xiong

Masters Theses

Two-carbon ring expansions of vinyl β-lactones, were carried out by Lewis acids (BF3-Et2O or Et2AlCl) via an ionization/cation rearrangement. β,γ-unsaturated δ-lactones were produced as efficient protocols for the synthesis of bioactive substances.

Vinyl β-lactones were prepared via ring closure of corresponding unsaturated β-hydroxy acids. Differently structured substrates were examined to study the influence of the substituents on the rearrangement. Other factors, such as temperature, solvent and catalyst were also studied in search of suitable reaction conditions.

This method is moderately successful in providing fused-ring δ-lactones, but higher yields (so far total yield of 24.8%) …


A Monte Carlo Model Of Uncertainty In A Deterministic Hazardous Waste Transportation Risk Assessment, Michael A. Cowen Jan 1997

A Monte Carlo Model Of Uncertainty In A Deterministic Hazardous Waste Transportation Risk Assessment, Michael A. Cowen

Masters Theses

This thesis is aimed at developing and applying advanced modeling tools in the prediction of risk to the general public from transportation of chemical waste on public highways. The modeling tools developed can then be used to compare alternative waste management scenarios. The application considered is related to the transport of hazardous waste generated by the United States Department of Energy (DOE) to current treatment, storage, and disposal facilities. DOE is currently considering four different scenarios.

The application considered can be more specifically defined as an analysis of the risk to the general public from transporting the 63 shipments of …


Identification Of Organosulfur Compounds In Illinois Coal, Mandy N. Amin Jan 1997

Identification Of Organosulfur Compounds In Illinois Coal, Mandy N. Amin

Masters Theses

The goal of this research was to identify representative organosulfur compounds in Illinois coal which are removed by a mild, chemical desulfurization procedure. Pyridine was used to extract three raw Illinois coals. Coal with a significant amount of elemental sulfur was treated with 1:1 HCl/HF followed by lithium aluminum hydride before pyridine extraction. Pyridine soluble extracts were extracted with tetrahydrofuran. Nickel boride desulfurization was performed on the soluble extracts of the three coals. The before and after desulfurized THF soluble extracts were fractionated and purified by liquid chromatography and the eluents were anlyzed by gas chromatography/mass spectrometry to characterize the …


Azo Dyes Based On 1,10-Phenanthroline, Minchong Mao Jan 1997

Azo Dyes Based On 1,10-Phenanthroline, Minchong Mao

Masters Theses

A series of new phenanthroline based azo-dye ligands, produced by diazotizing 5-amino-1,10-phenanthroline (5-NH2-phen) and then coupling this intermediate to a variety of coupling components, has been synthesized and characterized. The coupling components used were β-naphthol, phenol, and 2,6-dimethylphenol, and the three dye ligands were named phen-azo-β-naphthol, phen-azo-p-phenol, and phen-azo-2,6-dimethylphenol, respectively. 1H-NMR and IR spectra showed that the dyes exist primarily in the azo form in DMSO solution and as solids. UV-Vis spectra (in MeOH) showed intense (ε ≅ 104 M-1cm-1) absorptions ranging from 380 nm to 500 nm for these ligands.

The …


The Resolution Of Chiral Dialkylarylsufonium Ions By 1h Nmr Spectroscopy, Johnathan Whetstine Jan 1997

The Resolution Of Chiral Dialkylarylsufonium Ions By 1h Nmr Spectroscopy, Johnathan Whetstine

Mahurin Honors College Capstone Experience/Thesis Projects

The goal of this research was to design a rapid Nuclear Magnetic Resonance method to measure enantiomeric excess of chiral sulfonium ions by using chiral lanthanide shift reagents. The sulfonium ions studied were dialkylarylsulfonium ions. The shift reagent that was employed was Europium (III) surrounded by chiral ligands of 3-trifluoroacetyl-d-camphor (tfc), which is derived from (+)-camphor. Ethylmcthylphenylsulfonium ion was synthesized for study as a racemic and enantiomerically enriched mixture. The sulfonium ion was then ion-paired with the shift reagent for resolution of R and S enantiomers. The best resolution was obtained with the Eu(fod)4- shift reagent, with nearly baseline resolution …


Small Mammal Habitat Uses Of Two Natural And Created Wetlands In Southeastern Virginia, Amanda Mckenney Mueller Jan 1997

Small Mammal Habitat Uses Of Two Natural And Created Wetlands In Southeastern Virginia, Amanda Mckenney Mueller

Dissertations, Theses, and Masters Projects

No abstract provided.


Les Deux Faces De La Pensée De E. A. Martel, Jacques Choppy Jan 1997

Les Deux Faces De La Pensée De E. A. Martel, Jacques Choppy

International Journal of Speleology

Réunion de textes de Martel: 1 - Extraits du Nouveau Traité des Eaux Souterraines (1921), donnant l’essentiel de la pensée de l’auteur sur l’hydraulique et la morphologie du karst. 2 - En opposition à cette vision, rappelée de nombreuses fois par l’auteur, extraits de diverses publications (de 1894 à 1930), admettant qu’un fonctionnement en régime noyé était possible: Martel est donc l’un des tout premiers ayant observé des formes de creusement en régime noyé, et les ayant interprétées comme telles.


Distribution Of Freshwater Amphipoda In The Lake Matoaka/College Woods Area, Williamsburg, Virginia, Susan Alexandra Mahon Jan 1997

Distribution Of Freshwater Amphipoda In The Lake Matoaka/College Woods Area, Williamsburg, Virginia, Susan Alexandra Mahon

Dissertations, Theses, and Masters Projects

No abstract provided.


Suprachiasmatic Nucleus Neurons Are Glucose Sensitive, Adam C. Hall, Roselle M. Hoffmaster, Edra L. Stern, Mary E. Harrington, David Bickar Jan 1997

Suprachiasmatic Nucleus Neurons Are Glucose Sensitive, Adam C. Hall, Roselle M. Hoffmaster, Edra L. Stern, Mary E. Harrington, David Bickar

Chemistry: Faculty Publications

The suprachiasmatic nucleus (SCN) in the hypothalamus serves as the pacemaker for mammalian circadian rhythms. In a hamster brain slice preparation, the authors were able to record spontaneous activity from SCN cells for up to 4 days in vitro and verify a self-sustained rhythm in firing. The phase of this rhythm was altered by the concentration of glucose in the bathing medium, with time of peak firing advanced for a 20 mM glucose condition and slightly delayed for a 5 mM glucose condition, relative to 10 mM. The advancing effect of 20 mM glucose and the delaying effect of 5 …


The Effects Of User Interface Metaphors On The Learnability Of Computer Systems By Field Dependent And Field Independent Computer Users, Robert N. Urwiler Jr. Jan 1997

The Effects Of User Interface Metaphors On The Learnability Of Computer Systems By Field Dependent And Field Independent Computer Users, Robert N. Urwiler Jr.

CCE Theses and Dissertations

This study was designed to assess the differences in the learning performance (speed and accuracy) with which field dependent and field independent subjects could complete a set of checkbook management tasks using software employing a user interface making strong use of common checkbook management metaphors versus software employing an interface adhering to a defacto industry standard-based graphical user interface design guideline. It was hypothesized that both field dependent and field independent users would complete tasks more quickly and accurately using both user interface types.

From a population of traditional and non-traditional college students, 64 individuals volunteered to participate in the …


Keyboardless Visual Programming Using Voice, Handwriting, And Gesture, Jennifer Leopold, A. Ambler Jan 1997

Keyboardless Visual Programming Using Voice, Handwriting, And Gesture, Jennifer Leopold, A. Ambler

Computer Science Faculty Research & Creative Works

Visual programming languages have facilitated the application development process, improving our ability to express programs, as well as our ability to view, edit and interact with them. Yet even in programming environments, productivity is restricted by the primary input sources: the mouse and the keyboard. As an alternative, we investigate a program development interface which responds to the most natural human communication technologies: voice, handwriting and gesture. Speech- and pen-based systems have yet to find broad acceptance in everyday life because they are insufficiently advantageous to overcome problems with reliability. However, we believe that a visual programming environment with a …


User Defined Prewrites For Increasing Concurrency In Design Databases, Sanjay Kumar Madria, A. Embong Jan 1997

User Defined Prewrites For Increasing Concurrency In Design Databases, Sanjay Kumar Madria, A. Embong

Computer Science Faculty Research & Creative Works

We introduce a prewrite operation before a write operation is performed on design databases, a database that consists of objects as engineering designs. A prewrite operation does not actually make a design but it only makes available the model of the design that the transaction will produce in future. Once the prewrite design by a transaction is announced, the transaction executes a pre-commit operation. After the pre-commit, read operations can access the prewrite design even before the pre-committed transaction has finally made the design and committed. Therefore, our algorithm increases the potential concurrency as compared to the algorithms that permit …


A Concurrency Control Algorithm For An Open And Safe Nested Transaction Model, Sanjay Kumar Madria Jan 1997

A Concurrency Control Algorithm For An Open And Safe Nested Transaction Model, Sanjay Kumar Madria

Computer Science Faculty Research & Creative Works

We present a concurrency control algorithm for an open and safe nested transaction model. We use prewrite operations in our model to increase the concurrency. Prewrite operations are modeled as subtransactions in the nested transaction tree. The subtransaction which initiates prewrite subtransactions are modelled as recovery point subtransaction. The recovery point subtransaction can release their locks before its ancestors commit. Thus, our model increases the concurrency in comparison to other nested transaction models. Our model is useful an environment of long-running transactions common in object oriented databases, computer aided design and in the software development process


High-Order Object Model Based Software Analysis, Xiaoqing Frank Liu, Hungwen Lin Jan 1997

High-Order Object Model Based Software Analysis, Xiaoqing Frank Liu, Hungwen Lin

Computer Science Faculty Research & Creative Works

The integration of object oriented modeling and structured analysis (SA) for developing a well structured object oriented software system is a challenge for requirements analysts and software designers. Some of the existing object oriented modeling techniques adopt approaches that are very different from SA, and others have clumsily stayed with SA after a few modifications. Our High Order Object Modeling Technique (HOOMT) however, attempts to strike a mean between both extremes while at the same time provides an effective modeling method. HOOMT consists of two models, the High Order Object Model and the Object Information Flow Model. By using the …


Climatic Fluctuations And Tropical Troglobitic Evolution, Pedro Gnaspini Jan 1997

Climatic Fluctuations And Tropical Troglobitic Evolution, Pedro Gnaspini

International Journal of Speleology

No abstract provided.


Martel's Voyage To Russia In 1903, Arrigo A. Cigna Jan 1997

Martel's Voyage To Russia In 1903, Arrigo A. Cigna

International Journal of Speleology

The news concerning caves and karst reported in a Martel’s book on his voyage to Russia in 1903 are here listed and the cave maps are reproduced.


Edouard-Alfred Martel Et Les Cavernes De La Belgique, Daniel André Jan 1997

Edouard-Alfred Martel Et Les Cavernes De La Belgique, Daniel André

International Journal of Speleology

An exhaustive report on the activity of Martel in Belgium is here given. In particular some relevant passages of Martel’s letters and papers are also included.


Classical Interpretation Of The Quantum Description Of H- Photodetachment In Parallel E And B Fields, Qiaoling Wang, Anthony F. Starace Jan 1997

Classical Interpretation Of The Quantum Description Of H- Photodetachment In Parallel E And B Fields, Qiaoling Wang, Anthony F. Starace

Anthony F. Starace Publications

Total quantum mechanical cross sections for photodetachment of H- in parallel E and B fields are examined both analytically and numerically to extract information which has a classical interpretation, thereby complementing recent classical and semiclassical periodic orbit studies.


Development Of Monitoring Protocol For Created Wetlands : Project Summary For 1997, James E. Perry Jan 1997

Development Of Monitoring Protocol For Created Wetlands : Project Summary For 1997, James E. Perry

Reports


Appx. 1. Annotated bibliography -- Appx. 2. Field data sheet - Appx. 3.Monitoring protocol manual for created wetlands: draft manual.


Distribution Of Submerged Aquatic Vegetation In The Chesapeake Bay And Tributaries And The Coastal Bays - 1996, Robert J. Orth, Judith F. Nowak, David J. Wilcox, Jennifer R. Whiting, Leah S. Nagy Jan 1997

Distribution Of Submerged Aquatic Vegetation In The Chesapeake Bay And Tributaries And The Coastal Bays - 1996, Robert J. Orth, Judith F. Nowak, David J. Wilcox, Jennifer R. Whiting, Leah S. Nagy

Reports

SA V distribution data in this report are presented and discussed based on the segmentation scheme adopted by the Chesapeake Bay Program (Flemer et al., 1983) and described briefly in the Methods section of this report. This zonation scheme (Upper, Middle, and Lower zones) for Chesapeake Bay, which accommodates the Chesapeake Bay Program segmentation boundaries, was adapted from that used in previous SAV distribution reports (i.e., Orth et al., 1994) and established by Orth and Moore ( 1982), then modified by Orth et al., ( 1989). The 1996 data were edgematched using ARC/INFO GIS software, as were all the historical …


Limiting Spheroid Size As A Function Of Growth Factor Source Location, J. A. Adam, K. Y. Ward Jan 1997

Limiting Spheroid Size As A Function Of Growth Factor Source Location, J. A. Adam, K. Y. Ward

Mathematics & Statistics Faculty Publications

Solutions C(r) of the time-independent nonhomogeneous diffusion equation for three different piecewise-uniform source terms are used to examine the limiting size of multicell spheroids using a simple model which reproduces concentration-dependent mitotic behavior. A condition is derived under which nontrivial solutions do not exist (in all three cases), and a condition for the existence of a unique nontrivial solution is established for the case of growth-modifying factor (GMF) production throughout the spheroid. Qualitative behavior of the limiting size is established as a function of various physiological parameters. Of fundamental importance is the assumed GMF concentration threshold θ, …


An Introduction To Topological Quantum Field Theories, Michael Atiyah Jan 1997

An Introduction To Topological Quantum Field Theories, Michael Atiyah

Turkish Journal of Mathematics

No abstract provided.


Augmented Graded Rings, Mashhoor Refai Jan 1997

Augmented Graded Rings, Mashhoor Refai

Turkish Journal of Mathematics

In this paper we study the augmented graded rings and give the ralationship between these rings and stronger properties of graded rings.


On Some Bounds For The Solutions Of The Semi-Discretized Time-Dependent Ginzburg-Landau Equations, Erhan Coşkun Jan 1997

On Some Bounds For The Solutions Of The Semi-Discretized Time-Dependent Ginzburg-Landau Equations, Erhan Coşkun

Turkish Journal of Mathematics

We study the two-dimensional system of Time-Dependent Ginzburg-Landau Equations (TDGL) for modeling a thin film of superconductor subject to a uniform magnetic field. We discretize the TDGL for the space variables using bond variables and staggered grid partitioning technique. By investigating the temporal evolution of semi-discrete Helmholtz enery functional and that of Semi-discretized TDGL, we provide bounds for some observable physical quantities of interest such as superelectron density, supercurrent density, charge density, electric field, and induced magnetic field.


Polymer Light Emitting Diodes, Frank E. Karasz, Bin Hu, Zhou Yang Jan 1997

Polymer Light Emitting Diodes, Frank E. Karasz, Bin Hu, Zhou Yang

Turkish Journal of Chemistry

Polyphenylene vinylene-based conjugated-nonconjugated alternating block copolymers form the active chromophores in a series of light emitting diodes (LEDs). The quantum efficiency and brightness of these devices can be improved by several orders of magnitude by incorporation of appropriate carrier transport layers and by rational choice of electrodes. Further improvements can be gained by blending of the active chromophores with high or low molecular weight species.


Novel Architectures Of Macromolecular Systems, Gerhard Wegner Jan 1997

Novel Architectures Of Macromolecular Systems, Gerhard Wegner

Turkish Journal of Chemistry

An important thrust in modern macromolecular chemistry is to construct complex architectures either directly from monomer units, or to design macromolecules capable of forming a desired superstructure by self-organization. Chain-rigidity is an example of a structural principle leading to self organization depending on the aspect ratio of the molecular objects and their mutual interactions. These molecularly defined objects serve as the building blocks of systems for which ultrathin layers composed of hairy rod macromolecules (HRM) are an example. Depending on architectural details layered architectures of HRM are models for molecular nanocomposites, exhibit interesting optical, electrochemical, dielectric or barrier properties. They …


Analytical Applications Of Organic Conducting Polymer Electrodes, Nada F. Atta, George C. Russell, Z. Wang, N. Akmal, J.F. Rubinson, S.K. Lunsford, E. Karagözler, O. Y. Ataman, H. Zimmer, H.B. (Jr.) Mark, Ahmed Galal Jan 1997

Analytical Applications Of Organic Conducting Polymer Electrodes, Nada F. Atta, George C. Russell, Z. Wang, N. Akmal, J.F. Rubinson, S.K. Lunsford, E. Karagözler, O. Y. Ataman, H. Zimmer, H.B. (Jr.) Mark, Ahmed Galal

Turkish Journal of Chemistry

Electrodes modified by he electrodeposition of conducting polymers were used for the detection and quantitative determination of some inorganic, organic, and biological molecules. Monomers used were five membered ring heterocycles or crown ethers and their derivatives. The polymer films were deposited on glassy carbon or platinum substrates. The resulting electrodes were used in the amperometric mode or in the potentiometric mode for flow injection and chromatographic analyses. The results showed that the proposed modified surface catalyzes the oxidation of organic and biological compounds. The detection of electroinactive inorganic anions, such as F^-, Cl^-, Br^-, NO_2^- and NO^-_3 was also possible …


Reduction Of Combustion Generated Pollution: Process Modifications And Energy Efficient Power Cycles, Janos M. Beer Jan 1997

Reduction Of Combustion Generated Pollution: Process Modifications And Energy Efficient Power Cycles, Janos M. Beer

Turkish Journal of Chemistry

Theoretical bases of combustion process modifications aimed at the reduction of pollutant emission are examined. It is shown, as an example, of how the minimization of emissions of nitrogen oxides leads to a design protocol that translates results of modeling and of bench scale experiments into guidelines for industrial design. The formation and emission of polycyclic aromatic compounds is also considered, because their formation is strongly favored in "low NO_x flames". In power generation the pollutant emission can be reduced effectively by the improvement of the ``heat rate,"i.e., the thermodynamic efficiency of the power cycle. Combined gas turbine-steam cycles which …