Voltage sags are short duration of voltage reduction caused by system faults, overloads and starting of large motors. Voltage sags are the main causes of trips of various sensitive equipment. In order to understand the voltage-tolerance performance of some process control equipment, this thesis presents test results of some sensitive equipment (such as computers, AC contactors, high intensity discharge lamps and programmable logic controller) and provides their voltage tolerance curves. A number of magnitudes and durations recommended by IEC 61000- 4- 11 are used to perform the tests. With the performance information in hands, power quality requirements of different types of equipment and customer, and area of vulnerability for sensitive loads could be estimated.

Adjustable-speed drives (ASDs) are often used in commercial and industrial facilities to improve process control and save energy. However, ASDs are the sensitive load equipment as regards to voltage sag. During the sag, the dc-bus capacitor of a typical ASD will discharge depending on the loading condition. The voltage of the dc bus decreases and could lead to a trip of the device. In order to understand the voltage sag tolerance capability of ASDs. Based on IEC 61800-3 and IEC 61000-4-11, this research presents the test results of ASD subjected to voltage sags under different operating conditions. The tests focus on different types of voltage sags, operating situations and designs of ASDs.

A waterflood has been used as a secondary recovery process to maintain the reservoir pressure and displace the oil towards the producer. However, the existence of high-permeability zones (thief zones) can cause early water breakthrough and excessive water production, thus, leaving a significant amount of oil bypassed in heterogeneous reservoirs. In this work, thermally active (Bright Water®) and pH-sensitive polymers have been proposed as an in-depth conformance tool with detailed simulation studies. Thermally active polymers are triggered by temperature change, whereas pH-sensitive polymers are triggered by pH change. Upon activation, polymers provide high resistance to subsequent fluid flow and divert the flow into adjacent unswept zones. As a result, this leads to improved sweep efficiency, low oil-water-ratio, and incremental oil recovery. The modeling of a pH-sensitive polymer was based on the principles of the microgel modeling procedure developed by Huh et al. (2005). In addition, a modified model was developed to calculate equilibrium swelling ratio explicitly in terms of pH and ionic strength of solution instead of using a root-finding algorithm. Thermal active polymers were modeled in terms of gelation reaction, gel viscosity, gel adsorption, and permeability reduction factor. Thermally active and pH-sensitive polymers were coupled with UTGEL reservoir simulator in an attempt to assess applicability of these gels as a conformance tool. Sensitivity analysis studies were conducted through 3D synthetic models to investigate technical feasibility of thermally active and pH-sensitive polymers as an in-depth conformance tool. Results indicated that incremental oil recovery and conformance control depend on the polymer concentration, slug size, permeability contrast between matrix and thief zone, vertical to horizontal permeability ratio (kv/kh), treatment location, oil-to-water viscosity ratio, and adsorption level, among others. It is concluded in this study that the permeability contrast between matrix and thief zones appears to be one of the most important parameters that impacts treatment performance. Therefore, a high permeability contrast is a prerequisite to achieve technically and economically successful treatment. / text

The problem of archiving photos is becoming increasingly important as image databases are growing more popular, and larger in size. One could take the example of any social networking website, where users share hundreds of photos, resulting in billions of total images to be stored. Ideally, one would like to use minimal storage to archive these images, by making use of the redundancy that they share, while not sacrificing quality. We suggest a compression algorithm that aims at compressing across images, rather than compressing images individually. This is a very novel approach that has never been adopted before. This report presents the design of a new image database compression tool. In addition to that, we implement a complete system on C++, and show the significant gains that we achieve in some cases, where we compress 90% of the initial data. One of the main tools we use is Locally Sensitive Hashing (LSH), a relatively new technique mainly used for similarity search in high-dimensions. / text

Recently designated as a bioenergy crop, Sorghum is rather unique as it can produce large quantities of cellulose or sugar which can be used to produce advanced biofuels or compounds. Sweet sorghum contains high levels of sugars and biomass sorghums consist primarily of ligno-cellulosic biomass. Improvement of both sorghum types is essential for maximizing production and conversion efficiency. Photoperiod sensitive sorghum is thought to maximize biomass production yet maturity influence on biomass production and composition is not fully understood. Utilizing sorghum for sugar production has increased efforts to develop sweet sorghums with sugar yields similar to sugarcane. Hybridization of these species has been investigated with, until recently, little success. Testing newly developed intergeneric hybrids and improvement of parents used in their creation will determine their feasibility and improve hybrid performance. Objectives of this research are multifaceted. First, analyze photoperiod sensitive sorghum in varying day length environments to determine maturity effects on plant phenotype, composition, and QTL detection. Second, analyze intergeneric sorghum × sugarcane hybrids to determine agronomic performance in relation to sugarcane. Lastly, introgress the iap allele into sweet sorghum females for use in intergeneric hybrid creation. Photoperiod sensitive sorghum RILs were evaluated in College Station and Weslaco, Texas and Puerto Rico which caused differential expression of plant maturity. Genetic control of trait expression was high for each location. Results indicate gradual induction of plant maturity increases detection of phenotypic QTL and detection of compositional QTL increases when maturity effects on plant phenotype are reduced. Intergeneric sorghum × sugarcane F_1 hybrids were compared to sugarcane in Weslaco, Texas in 2011. Each hybrid expressed agronomic traits similar or better than that of the sugarcane variety. High levels of repeatability and genetic influence on trait expression were observed. Overall performance of the sugarcane variety was better than any individual hybrid tested. Introgression of iap into sweet sorghum was successful and generated seventeen new sweet sorghum female genotypes possessing the allele. Only two genotypes exhibited higher brix readings and both were later maturing than Tx3361. Height and maturity of all developed genotypes varied and desirability of developed lines was similar to Tx3361.

With an increase in the capabilities and sophistication of terrorist networks worldwide comes a corresponding increase in the probability of a radiological or nuclear device being detonated within the borders of the United States. One method to decrease the risk associated with this threat is to interdict the material during transport into the US. Current RPMS have limitations in their ability to detect shielded nuclear materials. It was proposed that directionally sensitive neutron detectors might be able to overcome many of these limitations. This thesis presents a method to create a directionally sensitive neutron detector using a unique characteristic of 10B. This characteristic is the Doppler broadening of the de-excitation gamma-ray from the 10B(n, alpha) reaction. Using conservation principles and the method of cone superposition, the mathematics for determining the incoming neutron direction vector from counts in a boron loaded cloud chamber and boron loaded semiconductor were derived. An external routine for MCNPX was developed to calculate the Doppler broaden de-excitation gamma-rays. The calculated spectrum of Doppler broadened de-excitation gamma-rays was then compared to measured and analytical spectrums and matched with a high degree of accuracy. MCNPX simulations were performed for both a prototype 10B loaded cloud chamber and prototype 10B loaded semiconductor detector. These simulations assessed the detectors' abilities to determine incoming neutron direction vectors using simulated particle reactant data. A sensitivity analysis was also performed by modifying the energy and direction vector of the simulated output data for 7Li* particles. Deviation coefficients showed a respective angular uncertainty of 1.86 degrees and 6.07 degrees for the boron loaded cloud chamber and a boron loaded semiconductor detectors. These capabilities were used to propose a possible RPM design that could be implemented.

The molecular structure of solvent and adsorbates at naturally occurring solid–liquid interfaces is a feature that defines much of the chemistry of the natural environment. Because of its importance, this chemistry has been studied for many decades. More recently, nonlinear optical techniques have emerged as a valuable tool for non-invasive investigation of environmental interfaces, in part because of their inherent surface specificity. Solid–aqueous interfaces are complex regions in which chemical and electrostatic forces combine to drive adsorption processes. Second-harmonic generation and sum-frequency generation (SFG) spectroscopies have been employed by many groups to investigate water structure at these interfaces over a range of pH and ionic strength environments. In this thesis, I report results of further investigation of water structure adjacent silica, fluorite, polystyrene, and poly (methyl methacrylate) surfaces in the presence of varying concentrations of Na+ and Cl– . A model is developed to describe the SFG response from the fused silica–solution interface as ionic strength is increased. This model reveals both details of interfacial water structure and the interplay between second- and third-order optical responses present at charged interfaces. In context of this model, water structure at the three other interfaces is discussed. Knowledge of the phase of the SFG response provides additional surface structural information that can be related to the polar orientation of a molecule or functional group, for example, a flip in the orientation of water at an interface. Methods to capture the phase information at exposed interfaces are well established, but buried interface phase measurement remains a challenge. Therefore, I focused on development of a systematic method for buried interface phase measurement. In this thesis, I demonstrate improvements in the precision and accuracy of two phase-sensitive SFG techniques for measurement of exposed interfaces. Results from efforts to extend the theory to the buried interface are presented, along with an examination of the challenges encountered along the way. / Graduate

国立情報学研究所で電子化したコンテンツを使用している。

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 185-189).

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