Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第16375号 / 工博第3456号 / 新制||工||1523(附属図書館) / 29006 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 岡 二三生, 教授 勝見 武, 准教授 木元 小百合 / 学位規則第4条第1項該当

The predictive values of standard and non-standard germination temperatures, standard accelerated ageing (AA) and saturated salt accelerated ageing (SSAA) tests were investigated. Germination tests were performed at standard and non-standard temperatures of 10°, 20°, 20°/30° and 30°C for cabbage and tomato, and 10°, 15°, 20° and 30°C for onion. The AA and SSAA tests were conducted using four relative humidities: standard AA (RH100), NaCl (RH75), Ca(NO3)2 (RH43) and MgCl2 (RH32). Emergence trials were also conducted at a range of temperatures (winter, 15°/25° and 30°C) and media (Hygromix and soil) using seedling trays. Correlations were calculated to evaluate the relationship between laboratory and emergence test results. Three onion seed lots that have different vigour levels were primed with PEG or NaCl and were germinated and planted under varying temperatures and levels of salinity. There were vigour differences among different seed lots of cabbage, onion and tomato seeds used in this study. Using the different laboratory tests, seed lots were distinguished as high, medium and low vigour seed lots. The low temperature germination test (10°C) for cabbage and onion; and 20°C for tomato were found to be effective for separation of seed lots according to their vigour levels. All SSAA vigour tests were also useful in differentiating seed lots based on their physiological stage of deterioration. Using the standard AA (RH100) the seed moisture content was high (29 to 45%), resulting in fungal growth. However, in the SSAA test the moisture content was below 14% and no fungal growth was observed. Ageing of seed lots using NaCl and MgCl2 resulted in a low narrow range of moisture contents, but using Ca (NO3)2 the range of the moisture content between seed lots was higher. For all crop seeds, there was no significant difference in the percentage emergence between the two growth media but larger seedlings were observed from the commercial growth medium (Hygromix). For cabbage, highly significant correlations were obtained between germination percentage at 10°C and RH32 and all emergence trials. In onion, the correlations were not consistent; highly significant correlations were observed from germination capacity (GC), 15°C, 20°C, 30°C, RH75 and RH32; and emergence parameters at specific conditions. However, the germination percentage from 30°C correlated significantly with the final emergence percentage and seedling vigour index. Germination of tomato seeds at 20°C and all SSAA had highly significant correlation with all emergence parameters. The germination rate parameters: MGT (mean germination time) and GI (germination index) were valuable in categorising seed lots with moderate vigour levels, however, except GE in cabbage and onion, all other germination rate characters failed to correlate with any emergence parameters. The radicle percentage germination (viability or GC) and final emergence percentage (FEP) were not enhanced by priming in all seed lots in the germination and emergence trials at all temperatures. The percentage of normal seedling was increased due to priming when seeds were subjected to low temperature and higher salinity levels. Priming was effective in improving the rate, uniformity of germination/emergence; and increased the seedling dry mass of onion seeds when grown under relatively cold environmental conditions. Priming was more beneficial for low vigour seed lots (seed lot A) than for high vigour seed lots (B, C). Priming also improved germination rate and uniformity at all salinity levels, but faster rate of emergence, more uniform and higher seedling dry mass were only observed when seeds were watered with low salinity levels (25 mM of NaCl). No significant difference was observed using NaCl or PEG as priming agent. Onion seeds are tolerant to salinity during germination and the effect of priming was more beneficial at emergence. / Dissertation (MSc (Agric) Horticulture)--University of Pretoria, 2007. / Plant Production and Soil Science / unrestricted

No description available.

Up-to-date methods of numerical modelling of random fields were applied to investigate some features of solute transport in saturated porous media with stochastic hydraulic conductivity. The paper describes numerical experiments which were performed and presents the first results.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / At present, the construction of highways in Andean areas the connect the various most important towns and cities in South America has become has become a key element for its development, since these routes and viaducts allow free access to cover basic needs of education, work, food and health of the population. Much of the land in these areas is clay soils whose behavior is quite unpredictable because they present abrupt volume changes according to the variation of saturation in the soil. People who travel on roads on slopes of this type of soil are at high risk due to the slippage that the slopes suffer each year. The most recent was on April 3, 2020 because of the heavy rainfall that was registered in the area; there was a landslide that affected communication channels in the department of Cajamarca in Peru [1]. In this type of slopes landslides occur when the clayey soil is specifically saturated, because under these conditions the soil is not stable and loses cohesion between its particles, therefore it is important to make slope stability studies taking into account the partially saturated soil. This article presents results of tests allow to recognize the physical characteristics of the clay soil in the province of Chepén in Cajamarca. In addition, the filter paper method is used to elaborate the soil-water characteristic curve and a series of direct shear tests are carried cut at different degrees of saturation. With these results, the partially saturate soil fault surface is constructed that allows visualizing the value of the shear stress of the soil according to the saturation to which it is subjected. This value will be important for calculating the safety factor that the slope floor must have of the resistance shear of the soil according to the saturation, this value will be important for the calculation of the safety factor that the floor of the slope must have so that it does not fall. Therefore, considering this condition of the partially saturated soil in the slope stability analysis provides values of the safety factor that are closer to reality, without the need to carry out the analysis in the most critical condition, such as what it done in classical soil mechanics.

The aim of the research is to investigate the effect of increased axle loading on saturated and unsaturated railway foundation materials for heavy haul applications. The research methodology comprises of a literature review to identify the lacuna in the scientific knowledge, finite element modelling for characterisation of railway cyclic loading, development of a cyclic triaxial apparatus for laboratory testing and experimental work, followed by analysis, interpretation and discussion of results and lastly the formulation of conclusions and recommendations. The axle loading of interest start with a base load of 20 tonnes per axle for general freight followed by increased axle loading of 26, 30, 32.5 and 40 tonnes per axle for heavy haul. The test materials used in the experimental work are representative of the subballast and subgrade layers in a railway substructure. As a reproduction of the climatic conditions in the field and the loading from passing trains, experimental testing was carried out on saturated samples under undrained conditions and unsaturated samples under constant water content. Unsaturated samples were prepared to matric suctions of 50, 100 and 225 kPa via axis translation. Monotonic and cyclic tests were conducted to investigate the behaviour of railway foundation materials. Critical state theory for saturated and unsaturated soils is used as a method of analysis in establishing the failure criterion and the failure envelope. Various parameters, such as stress states, strains, resilient modulus, pore water pressure and matric suction are also utilised in investigating trends and behaviours. Based on the monotonic test results, the shear strength of unsaturated samples was found to be greater than that of saturated samples, attributed mainly to strain hardening caused by the unsaturated soil conditions, with the presence of a peak deviator stress when plotted on the stress-strain graph. However, unsaturated samples were also found to be prone to load-collapse during monotonic shear, even when the water content and confining stress remained constant, which resulted in brittle behaviour with the sudden rupture and formation of multiple bifurcation shear bands and slip planes. Based on the cyclic tests on saturated materials, it was discovered that increased axle loading can result in phase-transition in soil behaviour, based on the stress states in the soil relative to the critical state line plotted in the effective stress space. Stress states below the critical state line resulted in a no-phase transition with dilation behaviour. Stress states on the critical state line resulted in a single-phase transition from dilation to contraction. Stress states above the critical state line resulted in a double-phase transition from dilation to contraction behaviour and then strain-softening. It is therefore concluded that increased axle loading can only be sustained by materials which presented dilation and no phase-transition in soil behaviour, which occurred at axle loading of 20 and 26 tonnes per axle for the subballast and subgrade materials. Based on the cyclic tests on unsaturated materials, it was established that increased axle loading did not cause material failure for all load axle cases and materials. The stress states of all tests plotted well below the failure envelope in the net stress space, which is indicative of resilient and elastic behaviour. Increased axle loading instead resulted in decreased permanent strain, until the critical level of repeated deviator stress of 32.5 tonnes per axle was found, where the permanent strain increased. It is therefore concluded that, as a result of the increased shear strength from the strain hardening property of unsaturated materials, an increased axle loading of 32.5 tonnes per axle can be safely sustained by the tested materials provided the matric suction in the soil is greater than 50 kPa. / Thesis (PhD)--University of Pretoria, 2020. / Civil Engineering / PhD / Unrestricted

Hyperlipidemia caused by a diet high in saturated fat can lead to visceral fat weight gain, obesity, and metabolic syndrome. Being over-weight from visceral fat has been linked to increased risk of developing most age-related diseases and disability, along with a lower income potential and quality of life. However, researchers are just beginning to understand the biological mechanisms that regulate the conversion of excess calories into visceral fat storage rather than glycogen or muscle. Epidemiological studies have repeatedly shown a comorbid association between age-related diseases involving hyperlipemia and circulating levels of uric acid, but not a direct association. This study utilized archival data from 31 healthy, middle-aged adults, who participated in a randomized, double-blind, crossover clinical trial on blood markers of lipidemia and inflammation following a high saturated fat (HSF) verses a "healthy" polyunsaturated fat (PUFA) meal. This primary study was conducted and funded by the National Institute on Aging. A secondary analysis of this data using Pearson's correlation with least squares (2-tailed) regression modeling found that when stratified by gender, baseline uric acid level was an independent and significant predictor of the lipemic response from the HSF, but not the PUFA meal. The linear regression plots indicated that males with uric acid levels above 4.5, and females above 3.0 mg/dL, had a progressively increased lipemic response to the HSF meal. The public health utility of this finding may include the clinical use of the gender-specific linear regression plots of uric acid values to identify and advise individuals at risk for hyperlipidemia from a diet high in saturated fats.

abstract: The study was to analyze the extent of bacterial transport in a two-dimensional tank under saturated conditions. The experiments were done in a 2-D tank packed with 3,700 in3 of fine grained, homogenous, chemically inert sand under saturated conditions. The tank used for transport was decontaminated by backwashing with 0.6% chlorine solution with subsequent backwashing with chlorine-neutral water (tap water and Na2S2O3) thus ensuring no residual chlorine in the tank. The transport of bacteria was measured using samples collected from ports at vertical distances of 5, 15 and 25 inches (12.7, 38.1 and 63.5 cm) from the surface of the sand on both sides for the 2-D tank. An influent concentration of 105 CFU/mL was set as a baseline for both microbes and the percolation rate was set at 11.37 inches/day using a peristaltic pump at the bottom outlet. At depths of 5, 15 and 25 inches, E. coli breakthroughs were recorded at 5, 17 and 28 hours for the ports on the right side and 7, 17 and 29 hours for the ports on the left sides, respectively. At respective distances Legionella breakthroughs were recorded at 8, 22 and 35 hours for the ports on the right side and 9, 24, 36 hours for the ports on the left side, respectively which is homologous to its pleomorphic nature. A tracer test was done and the visual breakthroughs were recorded at the same depths as the microbes. The breakthroughs for the dye at depths of 5, 15 and 25 inches, were recorded at 13.5, 41 and 67 hours for the ports on the right side and 15, 42.5 and 69 hours for the ports on the left side, respectively. However, these are based on visual estimates and the physical breakthrough could have happened at the respective heights before the reported times. This study provided a good basis for the premise that transport of bacterial cells and chemicals exists under recharge practices. / Dissertation/Thesis / Masters Thesis Civil, Environmental and Sustainable Engineering 2019

No description available.

No description available.