study was made of the solubility of synthetic hydroxyapatite (Ca₁₀(PO₄)₆(OH₂). The basic calcium phosphate was synthesized in CO₂ free systems, over a pH range of 5.0 to 8.0 using reaction temperatures of 40°, 60°, and 90°C, and reaction periods of 24 and 96 hours. The study was divided into two phases. In one phase the pH of the suspensions, and the calcium and phosphorus concentrations in solution were measured after precipitation and after redispersing the preparations in water. The application of solubility criteria to these studies showed that the differences in solubility obtained by synthesis with varying reaction period and temperature were not brought about by conditions of super saturation. Solubility was found to decrease with increased synthesis reaction period and increased temperature of synthesis. With a given temperature and synthesis reaction period the hydroxyapatite preparations had a uniform solubility. Solubility changed only when the conditions of synthesis were changed. X-ray diffraction analysis of the solid phase indicated that the solubility of hydroxyapatite decreased with increasing crystallinity. Examination with the electron microscope, however, showed that increased crystallinity was not due to increasing crystal size. Owing to the smallness of crystals, it was not possible to examine the hydroxyapatite with a petrographic microscope, and hence it was not possible to detect the presence of amorphous phases. It is possible, then, that small amounts of amorphous substances were present in the solid phase, and, as a result the apparent degree of crystallinity was altered. In the second phase, studies of the Ca:P mole ratios of the preparations showed that Mole ratios were not constant for any mode of synthesis. Further studies indicated that adsorption was of no, or at best, minor importance in determining the Ca:P ratios of hydroxyapatite. Isomorphous substitution with OH¯ions replacing PO₄¯ ions, and H₃O⁺ ions replacing Ca⁺⁺ ions might have occurred, but it was not possible to detect solubility differences which should result from this substitution. Hence it was not possible to correlate solubility with composition of hydroxyapatite. Even though the hydroxyapatite appeared to be of variable composition, it was found that this basic calcium phosphate had a definite pKsp value in the pH range of 5.0 to 8.0. / Land and Food Systems, Faculty of / Graduate

An apparatus has been designed to investigate the mechanical behaviour of soils under plane strain. Provision has also been made to consolidate specimens under condition of no lateral yield prior to their shear; thus simulating the consolidation state in natural sedimentary deposits. The apparatus is suited for testing both sands and clays, including undisturbed clay samples from standard size bore hole samplers. The design permits a variety of stress paths to be followed during shear. An experimental procedure for testing both sands and clays has been developed and some test results are described. The results obtained show a general confirmation of existing information on the behaviour of soils under plane strain. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Thesis (M.S.)--University of Wisconsin--Madison, 1964. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 74-78)

A study was made of the influence of soil moisture tension and soil temperature on the availability of phosphorus from five different compounds in two calcareous soils. In the study of moisture tension, the top six inches of Machete stony sandy loam and of Nisconlith clay loam were treated with five phosphate carriers of varying water solubility, monoammonium phosphate, monocalcium phosphate, anhydrous dicalcium phosphate, calcium metaphosphate and hydroxyapatite, at a rate equivalent to 120 pounds of P₂O₅ per acre. The soils were placed in empty crocks and weighed. These weights were used along with information obtained from previously prepared moisture tension curves to maintain the moisture tension ranges. The tension ranges used were: 0.2 - 0.4, 0.2 - 0.8, 0.2 - 2.0 and 0.2 - 6.0 bars. Irrometers were used to measure and control moisture tension ranges of 0.2 - 0.4 and 0.2 - 0.8 bars. The moisture tension ranges of 0.2 - 2.0 and 0.2 - 6.0 bars were measured gravimetrically. The soils were seeded with alfalfa and placed in growth chambers built in the greenhouse. Three cuttings of the plants were made at the third blossom stage and the dried plant tissue was analysed for phosphorus. At the end of the first cutting, NaHCO₃ extractable phosphorus was determined in these soils and dicalcium phosphate activity at the end of the third harvest. Statistical methods were used to determine the significance of the experimental results. The yields from both soils showed that a moisture tension range of 0.2 - 2.0 bars gave the best growth for the tensions. On the Nisconlith soils the other tensions gave yields that were almost as high as those obtained at 0.2 - 2.0 bars tension. This moisture tension was also the most favourable for phosphorus uptake as indicated by the phosphorus content in plant tissue. The effect of phosphorus source proved to be of no significance on the yield of alfalfa. The phosphorus content in plant tissue from the Machete soil was related to the degree of water solubility of the phosphate compounds. A significant difference between the effectiveness of the water soluble compounds, such as monoammonium phosphate and the water insoluble or citrate insoluble compounds such as hydroxyapatite, was observed. Soil moisture tension had a significant effect on the phosphorus content in plant tissue at a 10% probability. NaHCO₃ extractable phosphorus, removed from both soils after the first cutting, was not directly related to the degree of water soluble phosphorus content of the compounds added. On the Machete soil, monocalcium phosphate treated soil released the greatest amount of NaHCO₃ extractable phosphorus, yet the monoammonium phosphate is ten times more soluble in water. Moisture tension had no effect on the amount of NaHCO₃ extractable phosphorus released. Dicalcium phosphate activity calculated from the calcium, magnesium and phosphorus concentrations in the soil solutions proved to be unsuitable for predicting the availability of phosphorus from the phosphate compounds. These determinations might have proved otherwise if the fertilizer trials were of a shorter duration. In the study of the effects of two soil temperatures 10°C and 24°C, on phosphorus availability, the same two soils, Machete stony sandy loam and Nisconlith clay loam were used. The two soils were potted and five phosphate compounds added at a rate equivalent to 120 pounds of P₂O₅ per acre. These pots were seeded with alfalfa and subjected to soil temperatures of 10°C and 24°C. The first temperature was maintained by the use of a temperature bath placed in the greenhouse and the second temperature was maintained by placing the pots on the greenhouse bench. It was found that at the higher temperature of 24°C higher yields of alfalfa were obtained than at 10°C. No one phosphate source was outstanding in its effect on alfalfa yield from both soils. There was a trend towards increased NaHCO₃ extractable phosphorus with an increase in temperature in both soils. / Land and Food Systems, Faculty of / Graduate

The main purpose of this study was to delineate ecosystem forest types within the forest associations of the Coastal Western Hemlock Zone. This aim was realised through the study of the ecotope of 116 sample plots in fifteen different associations. The study involved examination of topographic position and macroscopic soil properties in all sample plots. Twenty-four soil profiles were analysed for chemical properties. The forest associations were divided into two or more forest types or kept as a single forest type. This was done by the author and coworker, L. Orloci, primarily on the basis of ecoptopic information. Results of the study of edaphic factors in relation to plant associations indicate that the moisture regime, soil depth, organic matter/nitrogen ratio and potassium concentration of the soils are the most important factors edaphically differentiating the forest associations. Soil succession studies included in this work suggest that the climate, the kind of vegetation and water economy of the soil determine the course of soil development. Soil succession may initiate on six essentially different kinds of substrata, in the Coastal Western Hemlock Zone. Soil forming processes contributing to development of soils are podzolization, gleyzation, melanization and peat formation in the study area. / Science, Faculty of / Botany, Department of / Graduate

This thesis examines some of the problems associated with urban sprawl, and attempts to determine the role of soil quality with respect to land use changes on four rural-urban fringe sites in the metropolitan Vancouver area. Part I describes various characteristics of, and problems created by, urban sprawl, its effects on the countryside, and reasons why it occurs. In Part II, the study sites are described in terms of soils, parent materials, drainage, and topography. In addition, physical and cultural information regarding the regions surrounding each site is given to portray each site in its larger context. Details and evaluation of the research results follow. Four sites, one in each of the municipalities of Delta and Langley and two in the Municipality of Richmond, were selected with features reflecting the physical heterogeneity of the Lower Fraser Valley and for their proximity to urban centres. Four series of air photographs were assembled and examined, in conjunction with soils maps, to determine what land use modification had occurred over a period of about twenty years. Land use changes were correlated with soils data to determine which soils were most affected by urban development. The results of this study appear to indicate that soil quality (for agriculture) by itself is insufficient to delay urbanization of fringe land. Other factors, such as isolation from urban centres, zoning provisions, and economic viability, are as important as soil quality in determining the fate of agricultural land on the rural-urban fringes of Greater Vancouver. / Land and Food Systems, Faculty of / Unknown

Pile foundations near the crest of a slope are often required to resist lateral loads. This is particularly important for piles at the abutments of bridges. However, limited full-scale test data are available to indicate how the lateral resistance of a pile would be affected when it is located near the crest of a slope. To investigate the effect of a slope on lateral pile resistance, three full scale lateral load tests were conducted on an instrumented steel pipe pile. For the first test, the pile was laterally loaded in horizontal ground. For the second test the pile was at the crest of a 30 degree slope and in the third test the pile was placed three diameters behind the crest of the 30 degree slope. The soil around the pile consisted of clean sand compacted to about 95% of the modified Proctor maximum unit weight for all three tests. Laboratory and in-situ direct shear tests indicated that the friction angle of the sand was approximately 39 degrees. The pile was instrumented with strain gages at approximately 1.5 ft intervals along its length so that the bending moment versus depth profile could be determined. Pile head load, deflection, and rotation were also measured. Based on the results, the presence of the slope decreased the ultimate lateral resistance of the pile-soil system by approximately 25% and 10% for tests two and three, respectively. The presence of the slope also resulted in an increase in the maximum bending moment of approximately 40% and 30% for tests two and three, respectively. Analyses using LPILE matched the lateral resistance for the pile in horizontal ground, but significantly overestimated the decrease in resistance due to the sloping ground. A mathematical model was developed to predict the ultimate strength of a pile located some distance from the crest of a cohesionless sloping profile. Parametric test results using the model were within 2.6 % of the measured results of tests two and three.