A Complete Chemical Analysis of Samples Taken from the Three Artesian Waters of Denton County (open access)

A Complete Chemical Analysis of Samples Taken from the Three Artesian Waters of Denton County

The purpose of this study was to determine the chemical content of Denton County's (Texas) water. Based on the analysis of the three samples, the water of Denton County is classed as poor for irrigation.
Date: August 1936
Creator: Allen, John William
System: The UNT Digital Library
A Quantitative Chemical Examination of Surface Well Water from the Three Principal Geological Divisions of Denton County (open access)

A Quantitative Chemical Examination of Surface Well Water from the Three Principal Geological Divisions of Denton County

A sample of the surface-well water was taken from an area of the predominating soil of each of the three geological regions of Denton County, Texas, and a chemical analysis of each sample was made. This thesis deals with the area from which the samples were taken, the methods of analysis used, and the results of the analysis.
Date: August 1936
Creator: Schnably, John Robert
System: The UNT Digital Library
Calcium Aluminates Synthesis, Characterization, and Hydration Behavior (open access)

Calcium Aluminates Synthesis, Characterization, and Hydration Behavior

The hydration behavior of the calcium aluminates as a function of the glass content, the curing temperature, and the water-solid ratio was investigated. In order to keep them from influencing the results, the free-lime content and the surface area of all samples were kept constant, whenever possible. Samples were hydrated with a water-solid ratio of 10/1 for periods of 1 to 90 days. Three curing temperatures were studied; 2°C, 25°C, and 50°C. Samples were hydrated in tightly sealed polyethylene containers to prevent reactions with atmospheric carbon dioxide. The hydration was followed by X-ray diffraction and thermal analysis. Only two samples, Hexacalcium Tetra-alumino Magnesium Silicate and Tricalcium Magnesium Dialuminate, were successfully prepared in an amorphous form. These compounds were used to investigate the effect of glass content on the hydration behavior. Results indicate that when the glass content is increased a corresponding increase is found in the percent combined water. Samples hydrated at 25°C were influenced by changes in the glass content to a greater degree than were those hydrated at either 2°C or 50°C. The effect of the water-solid ratio on the hydration behavior of the calcium aluminates was studied using the compounds; Hexacalcium Tetra-Alumino Magnesium Silicate/ and Dodecacalcium Hepta-Aluminate. …
Date: December 1984
Creator: Griffin, Joseph George
System: The UNT Digital Library
Precipitation and Pattern Formation under Far-From-Equilibrium Conditions (open access)

Precipitation and Pattern Formation under Far-From-Equilibrium Conditions

Precipitates of a series of alkaline earth metal (barium and strontium) carbonates, chromates, phosphates, and sulfates were formed at high supersaturation by diffusion through silica hydrogel, agarose hydrogel, and the freshly developed agarosesilica mixed gels. The reaction vessels could be a small test tube, a recently designed standard micro slide cassette and a enlarged supercassette. Homogeneous nucleation is thought to have taken place, and particle development led to the formation of an unusual category of materials, known as Induced Morphology Crystal Aggregates [IMCA], at high pH under far-from-equilibrium conditions. Standard procedures were developed in order to produce homogeneous gels. Particle development led to characteristic style of pattern formation, which I have called monster, spiral, and flake. Among these IMCA, barium carbonate, chromate, and sulfate were moderately easy to grow. Barium phosphate was very difficult to grow as IMCA due to formation of poorly crystalline spherulites. IMCA of strontium carbonate, chromate and sulfate could be developed at high basic pH in the presence of silicate. Strontium carbonate sheet morphology displays a unique property, double internal layer structure, which was identified by backscattering electron imaging (BEI). Selected electron diffraction (SAD) revealed a new crystal phase which was called "Dentonite". Precipitate particles were …
Date: August 1995
Creator: Chen, Peng, 1960-
System: The UNT Digital Library
Investigation of Substituent Effects of 2-Substituted Silaethylenes (open access)

Investigation of Substituent Effects of 2-Substituted Silaethylenes

This investigation is concerned with determining whether a carbon substituent or a silicon substituent on the carbon terminus of a silicon-carbon double bond has a more stabilizing effect. Two different 2-substituted silaethylenes were generated at the same time by pyrolyzing 1, 1-dimethyl-2-neopentyl-4- (dimethylalkoxysilyl) silacyclobutanes in a nitrogen flow system. The results of these pyrolyses, both neat and in the presence of a trapping reagent, show that the silaethylene with a silicon substituent on the carbon terminus was favored approximately two to one over the silaethylene with a carbon substituent. This datum, along with other observations and hypotheses discussed, leads to the suggestion that the silicon substituenton the carbon terminus of the silaethylene bond has a more stabilizing effect than the carbon substituent.
Date: December 1980
Creator: Snyder, Walter David
System: The UNT Digital Library
A Chemical Analysis of the Important Soils of Dimmit County, Texas (open access)

A Chemical Analysis of the Important Soils of Dimmit County, Texas

The purpose of this study is to collect sample soils from uncontaminated horizon (by digging completely through the soil profile or strata) and provide a chemical analysis of the important soils of Dimmit county, Texas.
Date: August 1938
Creator: Meek, William
System: The UNT Digital Library
An Analysis of Elementary Science Material Included in Certain Courses of Study and Text Books (open access)

An Analysis of Elementary Science Material Included in Certain Courses of Study and Text Books

The purpose of this study is to assess the contribution of elementary science to the curriculum. The finding of the investigation summarized in table form.
Date: August 1937
Creator: Maurice, Katherine
System: The UNT Digital Library