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Mass stabilization is not a common soil improvement method in Sweden, and even less so in sulfide soils. Previous research indicates that a linear elastic material model is suitable for settlements in stabilized sulfide soil. A construction project in the northern part of Sweden applied mass stabilization in sulfide soil. This was an opportunity to study the mass stabilized sulfide soil in the field. This master thesis was executed in parallel to that construction project.  Ground preparations in the project meant that 5-8 m fill would be placed on fine-grained sulfide soil. Soil improvement and specific foundation designs were determined to be required.  Mass stabilization of the sulfide soil was one of the soil improvement methods used. The binder recipe for the mass stabilization was determined to be 60 kg cement/m3. Which also was the binder recipe analyzed in this thesis. The goal of the thesis was to investigate if settlements in stabilized sulfide soil could be predicted with a linear elastic model. This was done by using soil parameters derived from: o   Back calculations of measured settlements caused by a test embankment. o   UCS tests. o   Oedometer tests. Deriving soil parameters by back calculation from the test embankment was done by: Assuming Terzaghi’s one dimensional consolidation theory. Defining the settlement curve by Casagrande’s logarithm of time fitting method. And then iterating the elastic modulus so that calculated settlements would match the defined settlements. The same method used for back calculations of the test embankment was performed in micro-scale on the Oedometer tests. Deriving soil parameters from the UCS tests was done according to previous recommended methods presented by (Al-Jabban, 2019) and (Åhnberg, 2006). The derived soil parameters were then used in a numerical model in Plaxis 2D to calculate settlements. The material model Mohr-Coulomb was used in Plaxis 2D. Three different settlement calculations were performed, one for each source of soil parameters. The calculated settlement results were compared to measured settlements caused by the test embankment. The calculated settlements gave good predictions of measured settlements in stabilized sulfide soil during immediate- and primary consolidation. However, depending on the binder recipe, secondary consolidation might occur in stabilized sulfide soil.  Some binder recipes underneath the test embankment seemed show no secondary consolidation. But the analyzed binder recipe, 60 kg cement/m3 experienced secondary consolidation. Secondary consolidation cannot be calculated with the linear elastic material model used in Plaxis 2D. Nor can it be evaluated from the UCS test. However, if secondary consolidation occurs, it can be added with hand calculations by parameters derived from “Casagrande logarithm of time fitting method.” The calculated settlements from back calculation of the test embankment and from the oedometer tests gave good predictions of the settlements during secondary consolidation. But this should be confirmed by measuring settlements over a longer period of time.  One advantage with soil parameters derived from laboratory investigations is that it is a faster method than soil parameters derived from back calculations of a full-scale field test.

α,α′-Bis[3-(N,N-diethylcarbamoyl)piperidino]-p-xylene enhances human blood platelet membrane integrity by exerting a stabilizing action at the level of the dense tubular system in surface membrane complexes known to sequester platelet calcium.

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The objective of this research was to compare the efficacy of portland cement to that of lime for improving the strength and durability of plastic clays. The scope of work associated with this research involved laboratory strength and durability testing of three plastic clays treated with portland cement or lime. To ensure a broad application of the work, the clays were obtained from three different regions of the United States, specifically from project sites near Bloomington, Indiana; San Antonio, Texas; and Monticello, Utah. Laboratory testing included evaluation of selected properties of the three clays in the untreated condition and in the treated condition. For the untreated condition, testing included measurements of soluble sulfate concentration, analysis of particle-size distribution, determination of treatment concentration using the Eades and Grim test, determination of Atterberg limits, development of moisture-density relationships, and measurement of California bearing ratio. In the treated condition, each clay sample was treated with either portland cement or lime, and testing included determination of Atterberg limits, development of moisture-density relationships, measurement of unconfined compressive strength (UCS), evaluation under wet-dry cycling, and evaluation under freeze-thaw cycling. For each of the three clay types, statistical analysis was performed to compare the strength and durability of the cement-treated specimens and the lime-treated specimens at each treatment concentration. Across all three clays, lime-treated specimens exhibited greater reductions in the plasticity index when compared to cement-treated specimens. In general, increased treatment concentrations corresponded to increased strength and strength retention. Percent strength retention of the cement-treated specimens was higher, on average, than that of the lime-treated specimens for the Indiana and Texas clays at low and medium concentrations. Similar strength retention was observed for cement-treated specimens and lime-treated specimens at high stabilizer concentrations across all three clays. In general, similar or significantly higher strengths were observed for specimens treated with cement than specimens treated with lime after 7 days, 28 days, and freeze-thaw cycling. Cement-treated specimens retained similar or greater mass after wet-dry cycling than lime-treated specimens. Cement-treated specimens also retained similar or greater strength after freeze-thaw cycling than lime-treated specimens, except for the Texas clay treated at the high concentration and the Utah clay treated at the medium concentration.

Abstract This study sought to develop an interval prone bridge fitness test to assess core stabilization in healthy adults (ages 18–39 years). Participants performed a prone bridge maneuver in alternating 15-sec work and 5-sec rest intervals with participants' RPE scores (0–10) recorded at the end of each work interval. The RPE score reported after 95 sec (RPE-95) was used to predict total interval prone bridge endurance time along with participants' self-reported level of physical activity (PA; sedentary = 0, low active = 1, active = 2, very active = 3). Multiple linear regression was employed to generate the following prediction equation (R = .86, SEE = 32.98 sec): Total time (sec) = 300.0 – (23.4 x RPE-95) + (17.7 x PA). Each predictor variable was statistically significant (RPE-95, p < .0001; PA, p = 0.006) and cross validation procedures using PRESS (predicted residual sum of squares) statistics revealed minimal shrinkage (Rp = .85 and SEEp = 32.89 sec). The mean and standard deviation (±SD) for the total duration of the interval prone bridge test and the RPE-95 data were 179.9 ± 65.2 sec and 6.3 ± 2.2, respectively. To assess test-retest reliability, a second test was completed about 48 hours after the first. The reliability study (n = 45) yielded an acceptable test-retest intraclass reliability coefficient (ICC = .95, SEM = 12.7 sec) when comparing total interval prone bridge endurance times across days. In summary, this interval prone bridge fitness test, and accompanying regression model, yields a relatively accurate estimate of total interval prone bridge test time in healthy men and women, using both RPE-95 and PA data.

Crop production systems which utilize the biomass produced by rye (<i>Secale cereale</i> ) to suppress weed growth and conserve soil moisture have been developed at Virginia Tech. The success of alternative, reduced-input crop production systems has encouraged research into the potential for breaking the traffic-tillage cycle associated with conventional tillage crop production systems. The fragile residues encountered in agricultural crop production, whether incorporated into the soil or distributed on the soil surface, provide minimal protection against compaction by wheeled vehicles. The potential of an intact cover crop to reduce machine-induced effects on soil properties that affect primary crop growth was the subject of this study. A randomized complete block experiment was conducted at the Whitethorne Farm in Montgomery County, Virginia. One set of plots was arranged on a terrace adjacent to the New River in a fine, mixed, mesic, Aquic Argiudolls. Another set of plots was arranged on an upland site, a river terrace tread, in a fine-loamy, mixed, mesic, Typic Hapludults. Three rye cover crop treatments were examined. In one, a live cover crop was completely undisturbed prior to tracking by a wheel-type tractor. In another, the cover crop was chemically desiccated, and in the third treatment, all above-ground biomass was removed from plots prior to machine traffic. The treatments permitted investigation of the effects of crop condition on machine-induced soil compaction and the contribution of root reinforcement to the alteration of soil response to machine traffic. A fall-tilled fallow treatment served as an experimental control. Three levels of traffic were investigated: one pass, three passes, and five passes. Undisturbed soil core samples were analyzed to determine machine-induced effects on dry bulk density, pore size distribution, and saturated hydraulic conductivity. The treatments affected soil response to machine traffic. The cover crop treatments altered the soil-plant microenvironment, affecting soil parameters that influence compactibility. Soil compaction was attenuated by the reinforcing effect of a network of undisturbed roots within the soil. There was no convincing evidence that above-ground biomass contributed directly to the reduction of machine-induced compaction effects. Soil response to machine traffic was limited to the uppermost 15 cm of the soil profile. / Ph. D.

yes / Condensate stabilization is a process where hydrocarbon condensate recovered from natural gas reservoirs is processed to meet the required storage, transportation, and export specifications. The process involves stabilizing of hydrocarbon liquid by separation of light hydrocarbon such as methane from the heavier hydrocarbon constituents such as propane. An industrial scale back-up condensate stabilization unit was simulated using Aspen HYSYS software and validated with the plant data. The separation process consumes significant amount of energy in form of steam. The objectives of the paper are to find the minimum steam consumption of the process and conduct sensitivity and exergy analyses on the process. The minimum steam consumption was found using genetic algorithm optimization method for both winter and summer conditions. The optimization was carried out using MATLAB software coupled with Aspen HYSYS software. The optimization involves six design variables and four constraints, such that realistic results are achieved. The results of the optimization show that savings in steam consumption is 34% as compared to the baseline process while maintaining the desired specifications. The effect of natural gas feed temperature has been investigated. The results show that steam consumption is reduced by 46% when the natural gas feed temperature changes from 17.7 to 32.7°C. Exergy analysis shows that exergy destruction of the optimized process is 37% less than the baseline process.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24179号 / 理博第4870号 / 新制||理||1697(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)准教授 水畑 吉行, 教授 若宮 淳志, 教授 倉田 博基 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM