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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Driveline Observer for an Automated Manual Gearbox

Juhlin-Dannfelt, Peter, Stridkvist, Johan January 2006 (has links)
The Automated Manual Transmission system Opticruise is dependent on signals from sensors located in different parts of the Scania trucks. These signals are of different qualities and have different update frequencies. Some signals and quantities that are hard or impossible to measure are also of importance to this system. In this thesis a driveline observer for the purpose of signal improvement is developed and estimations of unknown quantities such as road incline and mass of the vehicle are performed. The outputs of the observer are produced at a rate of 100 Hz, and include in addition to the mass and road incline also the speed of the engine, output shaft of the gearbox, wheel and the torsion in the driveline. Further the use of an accelerometer and the advantages gained from using it in the observer are investigated. The outputs show an increased quality and much of the measurement noise is successfully removed without introducing any time delays. A simulation frequency of 100 Hz is possible, but some dependency toward the stiffness of the driveline is found. The observer manages to estimate the road slope accurately. With the use of an accelerometer the road slope estimation is further improved and a quickly converging mass estimation is obtained.
102

Coupling of two natural complex systems: earthquake-triggered landslides

Ghahramani, Masoumeh January 2012 (has links)
This thesis contains two main parts. The first part presents a database compiling 137 landslide-triggering earthquakes (LTEs) worldwide, with magnitudes greater than the minimum observed threshold for causing landslides (M4.5), for the period of 1998 -2009. Our data sources include a comprehensive review of the existing literature on earthquake-triggered landslides (ETLs), and also a USGS-based earthquake catalog (PAGER-CAT) that contains information on earthquake-triggered secondary events. Only 14 earthquakes out of the 137 seismic events induced significant numbers of landslides (>250). We compared the number of ETLs with the total number of earthquakes with M ≥ 4.5 (n=68,734) during the same period of time. The results show that only 0.2 % of ETLs and only 4.5% of earthquakes of M > 6 resulted in landslide. In addition, we compiled a database of 37 large-scale landslides, involving initial failure volumes of greater than 20 Mm3 that occurred worldwide between 1900 to 2010. The database contains large-scale earthquake-triggered (n ETLs=18) and non-earthquake-triggered landslides (n NETLs=20), i.e., ca. 50% of large-scale landslides were induced by seismic activity. Surprisingly, the volume-temporal frequency curves of ETLs and NETLs show almost identical slopes and intercepts. Thus, for a given volume, the annual frequency of ETLs is almost identical to that of NETLs in the 110 year period. In contrast to previous studies, this thesis found that the volume of the largest landslide triggered by a given landslide-triggering earthquake is not a function of earthquake magnitude. Peak ground motions (PGA, PGV, and PSA) were calculated for the 18 large-scale ETLs at the site of each occurrence and the resulting values show a correlation with the volume of landslides below the threshold of ca. 80 Mm3. Above this threshold, the relationship between peak ground motions and ETL volume shows complex and nonlinear behavior. The results suggest that 1) other special conditions are required for significant earthquake-triggered landslides to occur, and 2) that very large earthquake-triggered landslides (volume greater than 80 Mm3) result from complex progressive failure mechanisms initiated by seismic shaking (i.e., above this threshold volume, landslide volume is independent of PGA, PGV, and PSA). A detailed analysis of the two 1985 Nahanni earthquakes and the North Nahanni rockslide triggered by the first main shock is carried out in the second part of the study. The North Nahanni rockslide, Northwest Territories, Canada was triggered by the earthquake of M=6.6 on October 5th, 1985. The slide occurred in a Palaeozoic carbonate sequence along a thrust fault, which partly follows bedding and partly cuts across bedding. The sliding surface within the limestone consisted of two planes; the lower plane dipped at 20° while the upper plane dipped at 35°. Slope stability analysis is performed using discontinuum numerical modeling. Static slope stability analyses indicate that the sliding rock was marginally safe for the sliding surface friction angles of 24o or higher. Dynamic analyses of the co-seismic movements are conducted by applying a series of sinusoidal waves to the base of the model. The amplitudes of the October earthquake's seismic waves are estimated using strong motion data available from the second main shock. The results, from the dynamic analysis indicate that the slope becomes unstable for given seismic inputs at a specific range of friction angles (24o to 30o) for the sliding surface and the deformation behavior of the North Nahanni rock masses is dependent on the frequency of the seismic signals. Because the static slope stability analysis showed that the slope was close to instability prior to the seismic shaking, we suggest that the 1985 Nahanni earthquake operated as a trigger event that accelerated the occurrence of the slide. This finding supports our earlier results of the global scale study, which showed that the triggering event does not change the general trend of the frequency-volume distribution of landslides; however, it can accelerate the occurrence of slope failure.
103

Boundary violations in forensic inpatient facilities : survey tool development and survey results

Daniels, Therese Anne 17 July 2008 (has links)
The primary objective of this study was to determine the incidence rate of boundary violations (BV) in forensic inpatient treatment settings, the extent and the nature of the violations, and the characteristics of individuals at risk to commit them. The Client-Staff Interactions (C-SI) survey was developed and used for these purposes. The survey was administered to 154 staff members in three inpatient settings. The tool demonstrated good internal consistency. Preliminary principal components analysis of the 10 summed section scores suggested three orthogonal higher-order components (Boundary Violations, Interfering Factors, and Supportive Factors). The results confirmed that while BV were occurring within the treatment settings, nonsexual violations were reported more frequently than sexual BV, and staff reported significantly less BV for themselves compared to their peers. The data supported the hypothesis and the proposed model, The Continuum of Boundary Domains (Daniels & Wong, 2007) that BV could be located on a continuum with underinvolvement at one end of the continuum and overinvolvement at the other end. It appears that some staff interpreted boundary crossings (BC) as BV rather than an acceptable therapeutic approach. <p> Reports of negative emotions were positively correlated with reports of BV, such that staff members who experienced higher levels of negative emotions also reported more BV. Supportive factors, such as seeking supervision and being engaged in activities that support the team, were correlated only with BC; however, engaging in these supportive activities did not decrease staff members negative emotional experiences. Staff under the age of 40 reported more disinterest (DIS) than staff who were over the age of 50, and degree-level prepared staff reported more DIS than diploma-level prepared staff. Some post-hoc explanations were offered for these observations. <p> It is recommended that continuing in-service education and discussions about appropriate boundaries are necessary to increase staff members knowledge regarding various types of BV, in particular disinterest (DIS) as a form of BV. The Continuum of Boundary Domains model can be used to conceptualize the various forms of BV.
104

A review of the management tactics against illegal use of slopelands in the Taitung County.

Zhang, Yao-wen 06 September 2005 (has links)
Taitung County is mountainous. Its geological structure is weak. Typhoon and heavy rain is frequent. Land erosion, landslide, and silt deposit in rivers is serious. In recent years, hilly areas are over-developed and conservation problem worsens. In typhoon and heavy rain, soil and other resources would be washed away and causes serious damage. The resources that people are relying on are vanishing. The purpose of this paper is to study the conservation of hilly areas, the management of river catchment areas, and the investigation and planning of the conservation of resources. This paper may help our people better understand the importance of conservation and t hey will be willing to work for a better Taitung Countye. This paper also studies the government conservation policies over the years and the their results, the farmers¡¦ understanding of the land, and conflict between the government and the farmers in land use in hilly areas. The study finds out that in managing the river catchment areas, government executive system is too complicated. Farmers do not appreciate the way the laws are implemented. They do not admit that their development cause water pollution or soil erosion. Rather, they believe that landslide and government policies in garbage dumping and road opening are to be blamed. Farmers are against most of the government policies especially in returning their land to government. There is a gap between government and farmer recognition. It is suggested that from now on, related personnel should investigate more and communicate more with people before preparing a policy. And since farmers are more willing to accept policies in subsidizing afforestation and soil protection, government should work on these issues.
105

Laboratory experiments on internal wave evolution on uniform slopes and topographic sills

Chen, Chen-yuan 21 January 2006 (has links)
Laboratory work were conducted to investigate the behaviors of an internal solitary wave (ISW) in a two-layer free surface fluid system in a wave flume (12m¡Ñ0.5m¡Ñ0.7m) at the National Sun Yat-sen University, Kaohsiung, Taiwan. A series of fundamental experiments on wave generation, propagation and interaction with uniform slopes and topographic features were carried out in the flume with stratified two-layer fresh/brine water. Factors governing the experiments included the thickness ratio of the upper and lower layers H1/H2, interface difference
106

Optimal Growth and Impatience: A Phase Diagram Analysis

Chang, Fwu-Ranq 10 1900 (has links)
No description available.
107

Evaluation of an approximate method for incorporating floating docks in harbor wave prediction models

Tang, Zhaoxiang 01 November 2005 (has links)
Computer models are nowadays routinely used in harbor engineering applications. Models based on the two-dimensional elliptic mild-slope equation can simultaneously simulate refraction, diffraction, reflection, and dissipation in completely arbitrary coastal domains. However, floating structures such as floating breakwaters and docks are often encountered in the modeling domain. This makes the problem locally 3- dimensional. Hence it is problematic to incorporate a floating structure into the 2-d model. Tsay and Liu (1983) proposed a highly simplified but approximate approach to handle this problem practically. The validity of their approach is examined in detail and it is found that the actual solutions deviate considerably from the theoretical solutions, although their approximation provides results with the correct trend. Therefore, correction factors have been developed and may be used to produce more reliable results using the framework of Tsay and Liu (1983). The resulting method is applied to Douglas harbor in Alaska. The result shows that docks in the harbor distort the wave field considerably and create a reflective pattern that can affect navigation safety in some areas. Also plots are developed for the transmission coefficients for waves propagating past rectangular and cylindrical floating objects of infinite extent for a wide range of conditions encountered in practice.
108

Determination of diffusion coefficient through laboratory tests and analytically validating it using empirical relations for unsaturated soils

Thakur, Anshuman Bramhanand 01 November 2005 (has links)
Soil suction is one of the most important physical variables affecting the soil engineering behavior, moisture content. Suction has a major controlling influence on soil shear strength. The moisture diffusivity properties of unsaturated properties of soils exert a critical influence on the depth to which seasonal variations of moisture and suction at the ground surface extend into the soil mass. Hence, a study of moisture diffusion coefficient is pivotal. In this research the drying test originally proposed by Mitchell (1979) has been validated by back calculating the moisture diffusion values using the empirical relation established by Lytton (2003). The non-linear flow through unsaturated soils has been simplified to a linear problem for simplicity in this study. Owing to this simplification, certain refinements have therefore been applied in the determination of diffusion coefficient. Thermocouple psychrometer was used to measure the soil suction along the length of the sample and at different times in the laboratory. Initial suction measurements were done using the filter paper test. Curve fitting procedure established by (Aubeny and Lytton, 2003), has been used for the determination of the diffusion coefficient. Analytical validation of the moisture diffusion coefficient, required coefficient of permeability, ??k??, slope of suction water characteristic curve ??S?? and air entry value ??ho?? as the major input parameters. Mitchell (1979) assumed the value of ??ho?? to be 100 cm. In this research air entry value, ??ho?? has been re-evaluated and it comes out to be higher than the pre estimated value. The value of slope of suction water characteristic curve, ??S?? obtained from pressure plate tests, compares well to the empirical equation of Lytton (2003). The results of moisture diffusion coefficient obtained from the empirical equation come out in the same range as obtained from the refined Mitchell??s (1979) drying test. The refinements includes introduction of constant temperature environment. Owing to the least variation in temperature, more reliable and reproducible data was obtained. The range of moisture diffusion coefficient, ??-values obtained from empirical equation, comes out to be coherent with the laboratory data. Hence, it can be concluded that the research was successful.
109

Investigations into the Shear Strength Reduction method using distinct element models

Fournier, Mathew 11 1900 (has links)
This thesis reports a detailed investigation into the use of the Shear Strength Reduction (SSR) method to determine factor of safety values in discontinuum models using the Universal Distinct Element Code. The SSR method depends on the definition of failure within the model and two different criteria were compared: the numerical unbalanced force definition and a more qualitative displacement-monitoring based method. A parametric study was first undertaken, using a simple homogeneous rock slope, with three different joint networks representing common kinematic states. Lessons learned from this study were then applied to a more complex case history used for validation of the SSR method. The discontinuum models allow for the failure surface to propagate based on constitutive models that better idealize the rockmass than simpler methods such as limit equilibrium (e.g. either method of slices or wedge solutions) and even numerical continuum models (e.g. finite difference, finite element). Joints are explicitly modelled and can exert a range of influences on the SSR result. Simple elasto-plastic models are used for both the intact rock and joint properties. Strain-softening models are also discussed with respect to the SSR method. The results presented highlight several important relationships to consider related to both numerical procedures and numerical input parameters. The case history was modelled similar to how a typical forward analysis would be undertaken: i.e. simple models with complexities added incrementally. The results for this case generally depict a rotational failure mode with a reduced factor of safety due to the presence of joints within the rockmass when compared to a traditional limit equilibrium analysis. Some models with large persistence of steeply dipping joints were able to capture the actual failure surface. Softening models were employed in order to mimic the generation and propagation of joints through the rockmass in a continuum; however, only discontinuum models using explicitly defined joints in the model were able to capture the correct failure surface.
110

Thermal Structure of the Central Scotian Slope: Seafloor Heat Flow and Thermal Maturation Models

Negulic, Eric 24 November 2010 (has links)
Many factors such as rift history, crustal structure and distribution of high thermal conductivity salt bodies throughout the sediment pile affect the present day thermal structure of the deepwater Scotian Slope. Understanding the basin's thermal evolution is crucial in determining the hydrocarbon maturation potential of this deepwater frontier basin. The Late Jurassic Verrill Canyon Formation of the deepwater slope has been inferred as the primary source rock interval for the Scotian Basin. However, to date, only twelve boreholes have sampled the Scotian Slope, and of these, none penetrate beneath the uppermost Jurassic sediments. Therefore, the distribution and maturation of deeper source rock intervals through standard vitrinite reflectance analysis remains unknown. In this study we attempt to better constrain the thermal history and maturation potential of the central Scotian Slope using a combination of recently acquired seafloor heat flow data, 2D seismic reflection data, available well data, simple lithospheric rift models and 3D thermal and petroleum systems modelling. We have derived a method of combining seafloor heat flow data with simple lithospheric rift models to provide first order constraints on the hydrocarbon maturation potential of frontier basins in dynamic 3D thermal models for regions lacking vitrinite reflectance and temperature data from boreholes. In July 2008, 47 seafloor heat flow measurements were acquired across the central Scotian Slope in an attempt to better constrain the region's thermal structure. Locations seaward of the salt diapiric province, thus unaffected by the high thermal conductivity of salt, recorded seafloor heat flow values of ~41-46 mWm-2. Significant increases in seafloor heat flow were noted for stations overlying salt diapiric structures, reaching values upwards of 72 mWm-2. The seafloor heat flow data have been corrected to remove the conductive effects of salt and the cooling effects of seafloor sedimentation on measured heat flow. The corrected data are compared with basal heat flux predictions from simple lithospheric rift models as constrained using crustal ( ) and lithospheric ( ) stretching factors after Wu (2007) to constrain heat flux history through time. Seafloor heat flow and simple modelling results suggest present day basal heat flux does not vary significantly across the slope. Present day basal heat flux across the central Scotian Slope is ~44-46 mWm-2. Basal heat flux curves from simple lithospheric rift models are used to constrain the heat flux history in 3D thermal and petroleum systems models of the central Scotian Slope. Numerous basal heat flux histories were tested to determine which heat flux history yielded the best match between modelled and measured seafloor heat flow data and to determine how varying basal heat flux affects the modelled hydrocarbon maturation of Verrill Canyon source rocks. The basal heat flux history which yielded the best match to measured seafloor heat flow data suggests that the Late Jurassic source rock interval rests primarily within the late oil window. Variations in radiogenic heat production across the margin associated with thickening continental crust were tested and suggest that significant variations in both maturation and seafloor heat flow may occur if radiogenic heat producing elements occur in high enough concentrations in the crust.

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