Dissertations / Theses on the topic 'Positive slope'

Pour améliorer la stabilité de réseau électrique et permettre une meilleure intégration des énergies renouvelables intermittentes, les Turbines-Pompes (TP) dans les Stations de Transfert d'Énergie par Pompage (STEP) sont utilisées plus loin de leur point de fonctionnement nominal en mode pompe. Une zone d'instabilité hydrodynamique limite le fonctionnement des TP en mode pompe pour la charge partielle (haute chute). Les performances d’une pompe en charge partielle restent cependant difficiles à prédire numériquement. Dans cette étude, des Simulations des Grandes Échelles (SGE ou LES) sont utilisées pour améliorer la prédiction de l'instabilité hydrodynamique survenant dans le cadre. Les simulations sont réalisées sur une géométrie complète de TP pour plusieurs points d'opération. Une approche Arbitraire Lagrangienne-Eulérienne (ALE) avec Adaptation Dynamique de Maillage (DMA) est utilisée pour prendre en compte la rotation de la roue. De plus une stratégie de convergence en maillage est utilisée et permet de garantir une bonne discrétisation du champ de vitesse moyenne et qu'une part suffisante de l'énergie turbulente est résolue. Une attention spécifique est donnée à la comparaison avec les résultats expérimentaux. Les simulations LES montrent des résultats similaires aux résultats d'essais réalisés par General Electric Hydro Solutions. Les décollements (tournants ou non) dans le cadre sont prédits à charge partielle par ces simulations. De plus, il est montré que ces décollements influencent l'écoulement dans la roue ce qui conduit à des lâchés tourbillonnaires proches des bords de fuite des pales. Ce phénomène génère des pertes et est responsable de la pente positive sur la courbe caractéristique de la pompe conduisant à un comportement instable de la machine. Des simulations SAS (Scale Adaptative Simulation) sont aussi réalisées sur la géométrie complète de TP. Ces dernières prédisent les mêmes pertes que les LES sauf dans la roue où elles manquent le phénomène de lâché tourbillonnaire au bord de fuite des aubes. D'autres simulations LES, sur une configuration simplifiée, permettent de mettre en valeur certains paramètres influençant les décollements dans le cadre. Ces travaux donnent ainsi un éclairage nouveau sur les instabilités hydrodynamique en charge partielle
For improved grid stability and better integration of intermittent renewable energies, Pump Turbines (PT) in Pump Storage Plants (PSP) are used in pump mode further away than their design point. In pump mode, the hump zone limits the operating range at part load (high head). The numerical prediction of the PT performances of this part-load instability is still challenging. In this study, Large Eddy Simulations (LES) are used to improve the prediction of the tandem cascade hump. Simulations on a full PT geometry are done for several operating points. An Arbitrary-Lagrangian-Eulerian (ALE) approach coupled with a Dynamic Mesh Adaptation (DMA) methodology is used to take into account the runner rotation. Moreover, a mesh convergence strategy is used to guarantee the accuracy of the mean field discretization, and to ensure the resolution of a sufficient part of the turbulent scales. Specific attention is paid to properly comparing simulations to experimental tests. Simulations results are in good agreement with experimental results obtained with platform tests made by General Electric Hydro Solutions. Part-load simulations predict (rotating or alternate) stalls in the tandem cascade. Moreover, it is shown that those stalls influence the flow in the runner where vortices, close to the trailing edges of the blades, are generated. This phenomenon generates losses and is responsible for the positive slope in the pump characteristic curve leading to unstable pump behavior. Scale Adaptative Simulations (SAS) are also used on the full PT geometry. The latter predict the same losses as LES except in the runner where they fail to predict the trailing edge vortices. Other LES simulations, on a simplified configuration, highlight parameters influencing tandem-cascade stalls. This study allows a new insight into part-load instability

A geographic information system (GIS) was used to create landform measurements and maps for elevation, slope, aspect, landform index, relative phenologic change, and slope position for 3 topographic quadrangles in Virginia. A set of known observation points of the Northern dusky flying squirrel (Glaucomys sabrinus) was used to build 3 models to delineate sites with landform characteristics equivalent to those known points. All models were built using squirrel observation points from 2 topographic quadrangles. The first model, called "exclusionary", excluded those pixels with landform characteristics different from the known squirrel pixels based on histogram analyses. Logistic regression was used to create the other 2 models. Each model resulted in an image of pixels considered equivalent to the known squirrel pixels. Each model excluded approximately 65% of the Highland study area, but the exclusionary model excluded the fewest known squirrel pixels (12.62%). Both logistic regression models excluded approximately 10% more known squirrel pixels than the exclusionary approach. The models were tested in the area of a third quadrangle with points known to be occupied by squirrels. After the model was applied to the third topographic quadrangle, the exclusionary model excluded the least amount of full-area pixels (79.30%) and only 14.81% of the known squirrel pixels. The second logistic regression excluded 81.16 % of the full area and no known squirrel pixels. All models proved useful in quickly delineating pixels equivalent to areas where wildlife were known to occur.
Master of Science

Sediment and nutrient loss from agricultural landscapes contributes to water quality impairment and has the potential to impact crop yield. Best management practices (BMPs) such as riparian buffers have been designed to combat these issues; however, concentrated flow paths (CFPs) reduce their effectiveness and are often overlooked in agricultural fields. Conventional management of CFPs is to fill and grade them, however this provides only a short term solution leading to their reformation and increased sediment loss. The objectives of this project were: i) to determine if the filling of CFPs influence crop growth (yield and biomass), ii) determine a distance at which crop growth is no longer influenced by CFPs, iii) assess the impact that topography and CFPs have on crop growth, iv) analyze water quality in surface runoff leaving crop fields via CFPs, and v) develop an economic analysis for CFP’s influence on crop returns. Six small agricultural catchments, CFPs, and topographic positions (i.e., depositional, backslope, and shoulder) were delineated using ArcGIS and LiDAR data. In each catchment, six 4 m2 plots were established along CFPs where crop biomass and crop yield were measured. Additionally, six plots with no influence from CFPs were established as reference plots. Surface water quality was assessed by taking edge-of-field grab samples at the CFP outlet during significant rain events (i.e., precipitation exceeding 2.5 cm). Water samples were analyzed for total suspended solids (TSS), total phosphorus (TP), dissolved reactive phosphorus (DRP), ammonium-nitrogen (NH4+-N), and nitrate-N (NO3- -N). Through this study it was shown that CFPs served as a conduit for transporting nutrient and sediment laden runoff to receiving waters, that increasing/decreasing distance from CFPs had an impact on crop yields, and that there was no crop yield advantage from the filling of CFPs vs. leaving them unfilled. Median values for NO3-N (1.85 mg L-1) and TSS (140 mg L-1) in the Fill catchments were higher than the No-Fill catchments (0.77 mg L-1 and 35.5 mg L-1, respectively), while DRP and TP concentrations were higher in the No-Fill catchments (1.31 mg L-1 and 2.37 mg L-1, respectively) compared to the Fill catchments (0.91 mg L-1 and 1.83 mg L-1, respectively) over the growing season. Crop biomass and yield results between the depositional and backslope positions were similar regardless of treatment, but were lower than the reference plots and shoulder position. Results from the economic analysis on the cost of farming in/near CFPs indicated that the economic return was greatly dependent on precipitation. CFPs are generally concave positions on the landscapes and have been eroded to a clayey subsoil, both resulting in greater water accumulation and retention than elsewhere in the field. During wetter years, an economic loss was incurred nearest to the CFP and during drier years, sites nearest to CFPs saw positive returns. Farmers and land managers may consider implementing stabilization measures, such as grassed waterways, in CFPs since crop yields are typically lower in wetter years, there’s increased cost to maintain these areas, and accelerated sediment loss can exacerbate the crop yield losses and impact on water quality.

The National Wetlands Inventory (NWI) is the definitive source for wetland resources in the United States. The NWI production unit in Hadley, MA has begun to upgrade their digital map database, integrating descriptors for assessment of wetland functions. Updating is conducted manually and some automation is needed to increase production and efficiency. This study assigned landscape position descriptor codes to NWI wetland polygons and correlated polygon environmental properties with public domain terrain, soils, hydrology, and vegetation data within the Coastal Plain of Virginia. Environmental properties were applied to a non-metric multidimensional scaling technique to identify similarities within individual landscape positions based on wetland plant indicators, primary and secondary hydrology indicators, and field indicators of hydric soils. Individual NWI landscape position classes were linked to field-validated environmental properties. Measures provided by this analysis indicated that wetland plant occurrence and wetland plant status obtained a stress value of 0.136 (Kruskalâ s stress measure = poor), which is a poor indicator when determining correlation among wetland environmental properties. This is due principally to the highly-variable plant distribution and wetland plant status found among the field-validated sites. Primary and secondary hydrology indicators obtained a stress rating of 0.097 (Kruskalâ s stress measure = good) for correlation. The hydrology indicators measured in this analysis had a high level of correlation with all NWI landscape position classes due the common occurrence of at least one primary hydrology indicator in all field validated wetlands. The secondary indicators had an increased accuracy in landscape position discrimination over the primary indicators because they were less ubiquitous. Hydric soil characteristics listed in the 1987 Manual and NTCHS field indicators of hydric soils proved to be a relatively poor indicator, based on Kruskalâ s stress measure of 0.117, for contrasting landscape position classes because the same values occurred across all classes. The six NWI fieldâ validated landscape position classes used in this study were then further applied in a public domain digital data analysis. Mean pixel attribute values extracted from the 180 field-validated wetlands were analyzed using cluster analysis. The percent hydric soil component displayed the greatest variance when compared to elevation and slope curvature, streamflow and waterbody, Cowardin classification, and wetland vegetation type. Limitations of the soil survey data included: variable date of acquisition, small scale compared to wetland size, and variable quality. Flow had limitations related to its linear attributes, therefore is often found insignificant when evaluating pixel values that are mean of selected pixels across of wetland landscape position polygons. NLCD data limitations included poor quality resolution (large pixel size) and variable classification of cover types. The three sources of information that would improve wetland mapping and modeling the subtle changes in elevation and slope curvature that characterize wetland landscapes are: recent high resolution leaf-off aerial photography, high-quality soil survey data, and high-resolution elevation data. Due to the data limitations and the choice of variables used in this study, development of models and rules that clearly separate the six different landscape positions was not possible, and thus automation of coding could not be attempted.
Master of Science

This report expands and clarifies previous classifications of non-forested plant communities from upper subalpine and alpine locations in coastal British Columbia. A total of 80 plots (releves) sampled specifically for this study were added to 202 releves from published and unpublished studies conducted since 1963. We used tabular and multivariate methods to synthesize and classify plant communities according to the Braun-Blanquet approach. Plant communities were classified into 37 vegetation units (associations or subassociations) which served as the basis of the resulting hierarchical classification. We describe the habitat and species composition of these vegetation units and their relationship to units recogized elsewhere in the Pacific Northwest. We then present eight generalized habitat types which we propose as the basic units for future ecosystem mapping. Each of these habitat types includes a predictable mosaic of vegetation units whose pattern occurs at too fine a scale to map individually.

Non-forested ecosystems dominate high elevation sites in coastal British Columbia, yet there has never been a comprehensive classification or mapping of all high-elevation community types. The objective of this study is to collate and expand upon previous classifications, and thereby to increase our understanding of the habitats and composition of these plant communities.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro
Esta dissertação buscou uma apreciação crítica e pragmática da relação entre desigualdade socioeconômica e obesidade abdominal, em resposta a proposição internacional de monitoramento das desigualdades em saúde e a escassez de estudos desta natureza relativos à obesidade abdominal. Dois artigos foram elaborados a fim de estimar o grau de desigualdade educacional na ocorrência de obesidade abdominal e revisar os estudos de associação entre posição socioeconômica e obesidade abdominal. O primeiro artigo utilizou o índice angular de desigualdade e o índice relativo de desigualdade em dados seccionais de 3.117 participantes da linha de base do Estudo Pró-Saúde, 1999-2001, e o segundo artigo abarcou os resultados de estudos conduzidos em população adulta no Brasil. Os índices de desigualdade resumiram a tendência monotônica e inversa observada entre escolaridade e obesidade abdominal na população feminina, proporcionando estimativas quantitativas desta desigualdade (artigo 1). Em concordância, observou-se que a associação entre indicadores de posição socioeconômica e obesidade abdominal foi majoritariamente inversa entre as mulheres, principalmente com relação à escolaridade, e estatisticamente não significativa entre os homens (artigo 2). Tal cenário epidemiológico evidencia que a obesidade abdominal tem afetado desproporcionalmente as mulheres de posição socioeconômica mais baixa e que a desigualdade de gênero na prevalência de obesidade abdominal tende a aumentar com menor posição socioeconômica. Em suma, a presente dissertação visou à produção de conhecimento epidemiológico relevante ao enfrentamento das desigualdades em saúde, com o objetivo premente de subsidiar políticas públicas de fato realizáveis e individualmente aceitáveis.
This dissertation sought to a critical and pragmatic assessment of the relationship between socioeconomic inequality and abdominal obesity in response to international proposition of health inequalities monitoring and to lack of studies of this nature relating to abdominal obesity. Two articles were prepared to -estimate the level of educational inequality in the occurrence of abdominal obesity, and review the association studies between socioeconomic position and abdominal obesity. The first article used the slope index of inequality and the relative index of inequality in the sectional data of 3.117 participants in the baseline of the Pró-Saúde Study, 1999-2001; and the second article encompassed the results of the studies conducted in the adult population in Brazil. The inequality indexes summarized strictly monotonic and inverse trend between educational achievement and abdominal obesity in the female population, providing quantitative estimates of this inequality (Article 1). Accordingly, we found that the association between socioeconomic position indicators and abdominal obesity was mostly reversed among women, especially regarding education, and statistically not significant among men (Article 2). This epidemiological scenario shows that abdominal obesity has disproportionately affected women of the lower socioeconomic position, and gender inequality in the prevalence of abdominal obesity tends to increase with lower socioeconomic position. In short, this dissertation aimed at the production of relevant epidemiological knowledge to addressing health inequalities, with the targeted of subsidize public policies feasible and individually acceptable.

In eastern Australia, the New England Fold Belt (NEFB) comprises an ancient convergent margin that was active from the Paleozoic until the late Mesozoic. Considerable effort has been expended in understanding the development of this margin over the past twenty years. However, proposed tectonic models for the orogen have either been too broad, ignoring contradictory local evidence, or too locally specific without paying attention to the 'big picture'. The research presented in this work addresses the issue of appropriate scale and depth of geological detail by studying the NEFB at the terrane-scale. Using one succession, the Silverwood Group of southeast Queensland, this work demonstrates that detailed sedimentological studies and basin analysis at the terrane-scale can help to refine hypotheses regarding the tectonic evolution of the NEFB. The Silverwood Group (Keinjan terrane), located approximately 140 km southwest of Brisbane, Australia, is a succession of arc-related basins that developed within an ancient intraoceanic island-arc during the mid-Cambrian to Late Devonian. From the base of the succession, the group consists of five formations totalling -9700 m. These include the Risdon Stud Formation (2500 m), Connolly Volcanics (2400 m), Bald Hill Formation (2450 m), Ormoral Volcanics (600 m) and the Bromley Hills Formation (1700 m). The Long Mountain Breccia Member (300m) is a separate unit which forms the lower part of the Bromley Hills Formation. The entire succession has been thrust west over the Late Devonian to Early Carboniferous Texas beds. Elsewhere, the Silverwood Group is unconformably overlain by and faulted against Early to Late Permian units including the Rokeby beds, Wallaby beds, Tunnel beds, Fitz Creek beds, Eight Mile Creek beds, Rhyolite Range beds and Condamine beds. Of these Permian units, all but the Condamine beds form part of the Wildash Succession. To the west, southwest and south, the Silverwood Group is intruded by the Late Triassic Herries and Stanthorpe Adamellites. All of these sequences and the two plutonic intrusives are unconformably overlain by the Jurassic sediments of the Marburg Sandstone. The Silverwood Group and Texas beds consist of various lithologies including grey, purple- grey, green and green-grey volcaniclastic conglomerates, sandstones, siltstones or mudstones, massive and laminated chert, polymict or monomict breccias, muddy breccias, muddy sandstones, and volcanic rocks. Volcanic rocks include various tholeiitic metabasites, dolerite, meta-andesites and infrequent metadacite. In the Silverwood Group, these volcanic rocks are often accompanied by mafic pyroclastic rocks (e.g. peperite and hyaloclastite). Facies analyses of these lithologies has led to the recognition of 19 deep-marine turbiditic and volcanic/volcaniclastic facies that were deposited by three main processes: i) gravity-flow processes (e.g. low- and high-density volcaniclastic turbidites and mass-flows), ii) chemical/biological processes (siliceous oozes- chert) and iii) direct initiation by volcanic processes (e.g. flows, hypabyssal intrusions and associated pyroclastic facies). For the Silverwood Group, the defined facies occur in distinct vertical associations that form recognisable 3rd and 4th-order architectural elements such as channel, levee, suprafan lobe, outer-fan, basin plain, mass transport complex, volcanic flows, syn-sedimentary sills and syn-sedimentary emergent cryptodomes. These architectural elements are represented in a series of deep-marine depositional environments including slope, shelf-edge failure, submarine-fan and subaqueous basaltic volcanoes. The Risdon Stud Formation and parts of the Connolly Volcanics were deposited along a 'normal' clastic or mud, mud/sand-rich and/or sand/mud-rich slope. Both upper and lower slope environments are represented and in both formations, the slope is speculated to have faced eastwards and prograded away from an active arc located west. Sediments from both successions accumulated at palaeodepths of 1200 to 2000 m. Although sediments from the upper part of the Bald Hill Formation were also deposited on a slope, these sequences have subsequently collapsed into the depocentre to form extensive slump deposits accompanied by olistoliths of older arc crust. The lower part of the Bald Hill Formation formed by similar processes, although the failure was far more extensive (>20 km along strike). This latter part of the formation is interpreted to be a major shelf-edge failure succession. Upper parts of the Bald Hill Formation also accumulated at palaeodepths of 1200 to 2000 m, but the deposition of these sediments occurred farthest from the shelf and at the greatest depth compared to the Risdon Stud Formation and Connolly Volcanics. Lower parts of the Bald Hill Formation were deposited at palaeodepths of approximately 1700 m. Subaqueous basaltic volcanoes are prominent in the Connolly Volcanics, Bald Hill Formation and Ormoral Volcanics. In the Bald Hill Formation, igneous rocks were emplaced into the shelf-edge failure succession as a series of syn-sedimentary sills and cryptodomes. These high-level hypabyssal rocks occasionally became emergent above the sediment-water interface, whereupon they were partially resedimented. In some parts of the Bald Hill Formation, the hypabyssal intrusions were blanketed by basin plain deposits that are contemporaneous with the slumps and olistoliths in the upper part of the formation. The intrusive rocks were emplaced at 1700 m palaeodepth. Unlike the Bald Hill Formation, the Ormoral Volcanics and lower parts of the Connolly Volcanics form thick accumulations of extrusive volcanic and pyroclastic rocks that built a significant volcanic pile. Volcanic and pyroclastic facies within these successions were deposited proximal to their source (0-10 km of vent). Extrusive rocks within the Ormoral Volcanics are thought to be derived from intrabasinal fissure-vents located at palaeodepths of 1700 to 3100 m. Igneous rocks from the Connolly Volcanics, Bald Hill Formation and Ormoral Volcanics have the petrological and geochemical characteristics of back-arc basin basalts (BAB) that were sourced from undepleted to slightly enriched Fertile MORB Mantle-wedge (FMM). The FMM material was variably enriched in trace elements by fluids derived from the subducting slab prior to emplacement of the igneous rocks. Immediately following emplacement, these rocks were hydrothermally metamorphosed under conditions of low-pressure and transitional low to high-temperature (200-300 °C). By contrast, igneous rocks within the Texas beds lack enrichment in subduction components and are characteristic of N-MORB. The Bromley Hills Formation is a sand-rich point-source submarine fan deposited at palaeodepths of 500 to 2000 m. The fan was initiated by a mass transport complex resulting from subaerial collapse of a basaltic-andesitic stratovolcano. The submarine fan is characterised by two repetitive stages of retrogressive sedimentation during which channel-levee elements (inner-fan channels) are overlain by suprafan lobe elements (mid-fan) and then by outer-fan deposits as sea-level rises within the depocentre. Both inner-fan channels and suprafan lobes show centralised stacking patterns with limited lateral migration that indicate the depocentre was laterally restricted during sedimentation (e.g. submarine ridges). The Bromley Hills Formation exhibits all the characteristics typical of an active margin fan that formed by a combination of tectonic stage initiation followed by eustatically controlled regressive deposition. Volcaniclastic sediments of the Silverwood Group range in composition from lithic to lithic- feldspathic wackes and arenites, although they are mainly lithic or feldspathic-lithic wackes and arenites. Many samples are tuffaceous (25-75% pyroclasts), particularly those from the Connolly Volcanics, Ormoral Volcanics and Bromley Hills Formation. Samples in the Bald Hills Formation and Texas beds can be classified as quartz-rich. The majority of the Silverwood Group was sourced from an undissected intraoceanic island-arc, although sediments within the Bald Hill Formation exhibit a provenance that is characteristic of uplift within the arc (recorded as a 'strike-slip continental arc' model). Epiclastic sediments from the Texas beds were sourced from a transitional to dissected continental arc. Formations of the Silverwood Group were mostly deposited in a series of intra-arc basins within an ancient intra-oceanic island arc, although the lowermost formation developed in a marginal basin (Risdon Stud Formation). All of the basins were located east of the active arc (behind the arc), keeping in mind the present location of the Group relative to the Texas-Coffs Harbour megafold. The entire succession formed during four-phases of arc-related basin development that coincide with major changes in the strain regime of the arc. From the base of the succession, these changes are: I) mid Cambrian to late Silurian marginal basin sedimentation- relative compression within the arc (Risdon Stud Formation), II) late Silurian to Early Devonian intra-arc rifting- relative extension within the arc (Connolly Volcanics), Ill) Early to early Middle Devonian basin collapse followed by intra-arc rifting- relative extension to compression (Bald Hill Formation and Ormoral Volcanics) and IV) early Middle to Late Devonian intra-arc submarine fan sedimentation- relative compression (Bromley Hills Formation). Comparing the Silverwood Group against equivalent terranes of Cambrian to Devonian age within the New England Fold Belt (NEFB) suggests that the Gamilaroi terrane, Calliope Volcanic Assemblage, Willowie Creek beds and Silverwood Group all formed as one intraoceanic island-arc during the Early to Late Devonian. Prior to this, significant differences in the sedimentological evolution of these terranes suggests that they occupied different positions relative to each other within the one arc. It is proposed that the NEFB formed as a result of dual west-directed subduction zones during the Cambrian to Middle Devonian period. During this time, a single intraoceanic island-arc located seaward of the Australian craton developed above a west-directed subduction zone. This arc was separated from the craton by a marginal sea. A second west-directed subduction zone was located beneath a continental arc developed on the Australian craton. Cambrian to Early Devonian terranes within and along the Peel Fault are proposed to form a part of the ancient subduction zone present beneath the intraoceanic island-arc (Weraerai and Djungati terranes). Collision of the intraoceanic island-arc occurred during the Late Devonian, at which point west-directed subduction occurred beneath the Australian craton and the accreted intraoceanic island-arc. Following collision, a new continental volcanic arc was established that was active during the Late Devonian to Early Carboniferous.

碩士
華梵大學
環境與防災設計學系碩士班
97
This study investigates the influence of loading position on slope displacements of colluviums through the tests by large-scale earth model and numerical simulation. In the tests of large-scale earth model, 30∘slopes of colluviums are constructed with the dimensions of 120cm in width and 80cm in height by static compression, then the loading plate is applied on the top of slope with the distances of 5cm, 10cm, 15cm, respectively, away from the edge of slope. From the results obtained in this study, it is found that the range of potential slip surface varies with respect to the distance of loading position. And the maximum normal displacement of slope increases with a longer elapsed time if the distance between loading plate and the edge of slope increase. It is also observed through the reading of dial gauges that the maximum displacements appears between one third and half of slope measured from tip of slope. The potential slip surfaces of the slopes tested are also simulated by STABL that are closed to the slip surface obtained by large-scale earth model with the factor of safe around 1.5. And the displacements measured by the simulation of DDA program are nearly the same as measured in the tests of large-scale earth model.

碩士
中原大學
土木工程研究所
93
When the soil with cracks in unsaturated slopes affected by rainfall, except that some rainfall becomes the surface runoff, other rainwater will be permeated with the crack under the surface. Because water infiltration besides making the water table rise, also increase the soil-water pressure, increase the glide stress of the soil, and decrease the anti-shear strength of soil, make slope becomes failure and deformation, even make it failure by slip. Generally the analyzed of slope steadily often neglects the influence of the crack, rainfall infiltration. We always let the soil body physical property as definite value in order to analyze its stability, and not considered that the change of crack, water content will influence the anti-shear strength of soil on time’s changing. So we can’t actually know when the collapse will happen by our slope stability analysis, so the analysis of slope depending yet not enough complete at present. This research will combine the method of rainfall, infiltration and slope stability analysis, and consider the slope crack in different position , applies FEMWATER software in simulating the soil moisture content after a rainfall depending on time’s changing, and the increase and decrease of groundwater. Next, there are different soil parameters in different moisture content. Then, it applies the mode of STEDWIN software to count each stage the relations between safety factors of slope and time. After the simulation test , we know that slope factor of safety will change which depends on the position of ceack. The failure will more easy happen when the slope crack in depth position or approaching the slope top, and the behavior of slope failure also will change with crack depth.

碩士
國立臺灣科技大學
電機工程系
107
This thesis proposes a hybrid approach to estimate the rotor position for a sensorless IPMSM close-loop speed control system. To achieve a wide adjustable speed range, two different sensorless methods are used. At the standstill and low speed, the current-slope measuring method of the zero voltage vector is used to estimate the rotor position. As a result, the IPMSM starts from standstill smoothly. At the middle and high speed, the extend back-EMF method is used to estimate the rotor position. The proposed method can operate the IPMSM drive system at different speeds from 0 r/min to 3000 r/min with good responses. To improve the dynamic responses of the proposed drive system, a predictive speed-loop controller is proposed to achieve fast transient responses, good load disturbance responses, and good tracking responses. In addition, to avoid the saturation of the input current, this paper also discusses the limitation of current input into the performance index to improve the poor response due to the controller’s constraints. A digital signal processor, TMS320F28379D with delta-sigma A/D converters are used as a control center to execute the rotor position/speed estimation algorithm and the control algorithm. Experimental results can validate the theoretical analysis to show the correctness and feasibility of this proposed method in the thesis.

This research work concentrate on developing digital soil maps to support field based plant phenotyping research. We have developed soil organic matter content (OM), cation exchange capacity (CEC), natural soil drainage class, and tile drainage line maps using topographic indices and aerial imagery. Various prediction models (universal kriging, cubist, random forest, C5.0, artificial neural network, and multinomial logistic regression) were used to estimate the soil properties of interest.