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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.
291

High speed digital protection of EHV transmission lines using traveling waves

Sidhu, Harjinder Singh 04 May 2004
Extra High Voltage (EHV) transmission lines are designed to transfer large amount of power from one location to another. The length exposed to the environment is a major reason for occurrence of faults on the lines. A fault on a high voltage transmission line affects the stability of the overall power system, which sometimes leads to permanent damage of the equipment. Relays are developed and installed to protect the lines. The transmission line protection relays, in the industry, are based on the fundamental frequency components of the voltages and currents. These relays need at least one fundamental frequency cycle for performing the protection operation. Voltage and current traveling waves are generated when a fault occurs on the transmission line. The velocity of propagation of traveling waves is finite and the level of the waves decreases with increase in the distance traveled. Information about the fault can be obtained by analyzing the traveling waves. A few traveling wave techniques, which are based on analog signal processing, to protect transmission lines have been proposed in the past. Two digital techniques, which use traveling waves for protecting EHV transmission lines, are proposed in this thesis. The traveling waves are extracted from the modal voltages and currents at the terminals of the transmission line. The techniques identify and locate the fault by using the information contained in the waves. A power system was modeled in the Electromagnetic Transient Direct Current Analysis (EMTDC) and several cases were created by varying different parameters related to the fault, fault type, fault location, fault resistance and fault inception angle. The techniques were implemented in hardware and their performance was tested on data, generated from the EMTDC simulations. Some cases are discussed in the thesis. The performance of the digital techniques for protecting EHV transmission lines using traveling waves was confirmed to be satisfactory. The proposed techniques provide protection at speed and discriminate well between internal and external faults.
292

Doing the Right Thing: Negotiating Risk and Safety in Child Protection Work with Domestic Violence Cases

Jenney, Angelique 31 August 2011 (has links)
The concepts of risk and safety are central to social work practice with survivors of violence against women, especially within the child protection system. Recent studies have highlighted how discrepancies between client and worker perceptions may create problematic conditions for developing effective intervention strategies (Dumbrill, 2006; Jenney, Alaggia, Mazzuca, & Redmond, 2005). In addition, tensions exist between movement toward improving worker-client interactions through collaboration and the use of standardized risk and safety assessments as a means of improving practice. The purpose of this research study was to explore how women’s narratives of domestic violence (DV), expressed within the context of child protection services (CPS), become translated into CPS workers’ assessments of risk and need for safety planning. Using Grounded Theory Methodology (GTM), this qualitative study used focus group and interview data to explore how both workers and clients’ experiences of the process of risk assessment and safety planning influenced the course of the intervention. What emerged is that workers and clients held similar representations about the social construction/collective representation of woman abuse and the work of CPS. For both worker and client participants the concept of ‘doing the right thing’ presented itself as an over-arching theme. This theme implies that there is a perceived ‘right way’ of addressing DV cases within CPS work and enhances understanding about the ways in which social workers and clients interact. These findings illustrate how narrative structures shape interactions that take place within the context of care and prevention, manifesting themselves in complex ways that can lead to misunderstanding the impact on children, the (un) conscious subjugation of women victims, and the absence of dialogue about the role of men in addressing DV at a system level.
293

Chemistry and the Automotive Industry

Pedigo, Jeremy 01 May 2008 (has links)
This thesis covers the use of chemistry in the automotive industry with emphasis on environmental compliance via chemical reporting by database and internal Energy Dispersive X-ray Fluorescence (XRF) screening, third party laboratory material testing, and the future of the chemist in the United States (U.S.) automotive industry. The third party testing was performed at Western Kentucky University (WKU) via the Materials Characterization Center (MCC), Institute for Combustion Science and Environmental Technology (ICSET) Thermodynamics Laboratory, and using the Scanning Electron Microscope/Energy Dispersive X-ray Spectrometer (SEM/EDX) managed by the WKU Biotechnology Center. Furthermore, the tests conducted were used to investigate material defects, provide solid third party quantitative results to support our XRF screenings to ensure environmental compliance, and determine cost effective material replacements. The company for which the testing was performed and information obtained is involved with the production of electronics for many of the major automotive companies throughout the world. The company specializes in the production of wiring harnesses, electrical control units (ECU), boxes (junction, fuse, relay, etc), and electrical components. These four areas control everything from the vehicle's lights, CD/DVD player, and heater to windows, locks, and navigation system. The automotive industry is extremely competitive; therefore, each company must continually change and improve in order to survive. New materials are constantly required to meet the reduced costs implemented by the customer, as well as, improve the function and quality of the components, while maintaining compliance with global environmental standards.
294

Exposure Assessment of Mercury in Fish from Kentucky Surface Waters

Gubari, Najla 01 May 2005 (has links)
Consumption of fish contaminated with mercury is the primary exposure pathway by which humans are exposed to mercury. Mercury is known to be a neurological toxin that can cause attention and language deficits, impaired memory, and impaired visual and motor function, especially in children under the age of six. In addition, mercury exposure can lead to other health problems in adults, such as damage to the kidney and increased risk of coronary heart disease. This study assesses the exposure to mercury through consumption of fish from Kentucky surface waters. The exposure assessment is based on data collected by the Kentucky Department for Environmental Protection (KDEP), Division of Water, from different streams and lakes in Kentucky and average consumption rates defined by the U.S. Environmental Protection Agency (EPA). The design of this study is established to determine if people in Kentucky are at risk of mercury contamination and whether the Kentucky fish advisory protects the population from this threat. The exposure analysis presented examines mercury in different fish species from different streams and lakes in Kentucky. Fillet samples of fish were examined by KDEP and the quantity of methylmercury was determined in micrograms per kilogram (ppm). These data were used to estimate the exposure under various scenarios for methylmercury. Exposure assessment is a major component of the risk assessment process and is used here to assess the magnitude of methylmercury contamination for people in Kentucky that consume fish. EPA has been determined the maximum contaminant level of mercury in fish to be 1 ppm, and stated that the general consumer should be advised to eat no more than 1 meal/week of noncommercial fish in the U.S. at this level. Also, they determined the reference dose of methylmercury to be 0.1 (J.g/kg of body weight/day. The result of categorizing Kentucky fishes according to EPA monthly risk-based fish consumption limits indicated that 22.8% of the fishes caught from lakes and 31.44% of the fishes from streams had a greater risk than the current Kentucky advisory would indicate. The calculated daily intakes of methylmercury have shown that the consumption of certain types of fish from lakes and streams will lead to ingestion of methylmercury that exceeds the acceptable level as determined by EPA.
295

Analysis of Soil Lead Levels in an Historic District of a South Central Kentucky City

Cummins, Robert 01 August 2003 (has links)
Lead in soil has been shown to be a significant pathway of lead exposure in children. Several factors including age of housing units, exterior composition, and paint loading may affect the amount of lead present in the soil. The purpose of this study was to analyze soil lead levels on properties located in an historic district and relate those levels to the variables previously mentioned. A total of 30 soil samples were collected from housing units in a nationally recognized historic district. Concentrations of lead in the soil were analyzed using a NITON X-ray Fluorescence Spectrum Analyzer, following EPA Method 6200 and the instrument protocol. Significant differences were found between the soil lead levels and paint loading (fully painted vs. non-painted). Significant differences were also found between soil lead levels and exterior surface (frame, brick, and other). A correlation analysis revealed there was no correlation between housing age and soil lead levels. Soil lead can be used as a predictor of blood lead levels in children. Using the information regarding soil lead concentration, the relative risk of exposure to lead and the subsequent health effects can be estimated for children living in the study area. The results from this study can also be used to initiate other studies and develop educational strategies for the district.
296

Study of the Distribution and Variation of the Herbicide Atrazine in Finished Drinking Water at a Small Community Water System in Kentucky

Golla, Vijay 01 July 2003 (has links)
This study examines the variation in the distribution of the concentration of atrazine, a triazine herbicide used in Kentucky to control weeds primarily in corn fields. Atrazine is known to have carcinogenic properties and is an endocrine disruptor in aquatic species even at low concentrations. Atrazine has the ability to be transported through the environment into water bodies due to its physical and chemical properties favoring its occurrence and distribution. Raw and Finished drinking water samples were collected from the Lewisburg water treatment plant which derives its drinking water supplies from a source water intake namely Spa Lake, which has a direct run-off from the fields with abundant atrazine application. Atrazine was analyzed in the collected water samples and was found in both the raw and finished drinking water in concentrations exceeding the Maximum Contaminant Level (MCL) of 3 ppb as established by the US Environmental Protection Agency (US E.P.A).The Safe Drinking Water Act (SDWA) methodology requires quarterly sampling strategy to be implemented by all small community water systems to monitor and control the concentrations of atrazine in finished drinking water. The presence of missing high concentrations of atrazine in finished water which are not measured in the regular quarterly sampling protocol is of concern for exposures and protection of public health and environment.
297

Transport of the Herbicide Atrazine on Suspended Sediments During a Spring Storm Event in Mammoth Cave, Kentucky

Anderson, Michael 01 May 2002 (has links)
This study examines the transport of atrazine, an herbicide used in Kentucky to control grassy and broad-leaf weeds in corn fields, on suspended sediments. Atrazine is a known carcinogen and endocrine disruptor and has been shown to be toxic at low environmental concentrations. Atrazine has the capacity to adsorb to soil particles, which in karst areas such as those found in south central Kentucky can be transported directly into the groundwater. Suspended sediments and water were collected from a well at the Hawkins River in Mammoth Cave National Park during a spring storm and tested for atrazine. Atrazine was found in concentrations exceeding 3 |ig/l in all of the sediment samples collected. Concentrations of atrazine in the cave stream's water were low, ranging from nondetectable traces to 0.1 (j.g/1. These results indicate that, in some cases, adsorption to sediments may be a major mechanism for atrazine transport in karst regions. The relatively high levels of atrazine present on the suspended sediments raise serious concerns, since this mode of transport has received little attention in karst environments.
298

Park and Ride Feasibility Analysis for the Evansville, Indiana, Metropolitan Area

Howard, Brian 01 May 2001 (has links)
Congested roadways and declining air quality standards are major concerns for many communities faced with the challenges of suburban growth and city decay. How each community chooses to fight the problems created by urban sprawl depends greatly on individualized characteristics of the community. Analyzing and understanding unique values of each community provides a sound foundation for measures designed to promote sustainable growth initiatives. The Evansville, Indiana, region is experiencing many of the growing pains associated with increased residential, commercial, and industrial development. Many roadways are currently strained near capacity, and traffic problems are anticipated to increase over the next 20 years. Evansville was ranked 68 out of the 271 worst sprawling MPOs, and Vanderburgh County will be designated as "non-attainment" with the next EPA air quality ruling. This research demonstrates that the Evansville region has problems with urban sprawl, air quality, and roadway congestion. Local air quality data, roadway congestion, employer and employee surveys, and commute patterns are all analyzed to determine the existing characteristics of the community. As a means to mitigate current and future concerns, Travel Demand Management (TDM) strategies such as park and ride facilities should be utilized. Implementing shared used park and ride facilities will provide an effective and relatively inexpensive method of congestion reduction by providing motorists with a different commute option.
299

Dye Tracing to Delineate Drainage Basins and Determine Groundwater Sensitivity, Mammoth Cave, Kentucky; with Special Reference to Potential Groundwater Contamination from Spills Along Interstate I-65

Capps, Arthur 01 August 2001 (has links)
The Mammoth Cave System of south central Kentucky encompasses more than 560 km of surveyed cave passages. The largest groundwater basin (244 km2) found within this cave system emerges from the Turnhole Bend Spring on the Green River. During high flow conditions, water from this groundwater basin will spill over into the Echo River section of the cave. Previous research, including cave mapping and dye tracing (Quinlan and Ray, 1989; Currens and Ray, 1998; Coons, 1994), has delineated the boundaries of spring groundwater basins for numerous springs along the Green and Barren Rivers. These data showed that 60% of the water that flows through the Turnhole Bend Aquifer comes from beyond the boundaries and protection of Mammoth Cave National Park. This area outside the park is crossed by several major transportation routes, including Interstate 1-65, U.S. Highway 31 -W, and CSX Railroad. Because the Turnhole Bend Aquifer is crossed by these major transportation routes, the aquifer is vulnerable to contamination from accidental spills of hazardous materials. Dye tracing methods were utilized to better delineate the boundaries and sub-basins of the Turnhole Bend Groundwater Basin along Interstate Highway 1-65. The approximate boundaries developed by previous research by others were first used to located areas that had not been previously dye traced. Fluorescent dyes were used as tracers and were detected by both qualitative (yes/no) methods and by quantitative (discrete water sampling) methods. Data from quantitative dye traces performed during this research provided additional information on the behavior of water flow into and through the maturely karstified limestones found in the south central Kentucky karst. Dye traces performed during the wet season, late winter and spring, have shown that average flood pulse groundwater flow velocities often exceed 1 km/hr. These high flow rates are contrasted by flow rates in the order of 0.5 km/day during the summer when evapotranspiration is high and rainfall is less frequent. Data from the quantitative dye traces also indicate a significant difference in the residence times of the dye between the wet and dry seasons. Dye that was injected during the wet season had a relatively short residence time in the cave streams of approximately 2 to 3 days. Dry season quantitative dye traces are very different with residence times of over 12 days being recorded. This information is vital in determining the consequences of a sudden release of hazardous materials within the drainage basin of Mammoth Cave and demonstrates that emergency planning is crucial.
300

Doing the Right Thing: Negotiating Risk and Safety in Child Protection Work with Domestic Violence Cases

Jenney, Angelique 31 August 2011 (has links)
The concepts of risk and safety are central to social work practice with survivors of violence against women, especially within the child protection system. Recent studies have highlighted how discrepancies between client and worker perceptions may create problematic conditions for developing effective intervention strategies (Dumbrill, 2006; Jenney, Alaggia, Mazzuca, & Redmond, 2005). In addition, tensions exist between movement toward improving worker-client interactions through collaboration and the use of standardized risk and safety assessments as a means of improving practice. The purpose of this research study was to explore how women’s narratives of domestic violence (DV), expressed within the context of child protection services (CPS), become translated into CPS workers’ assessments of risk and need for safety planning. Using Grounded Theory Methodology (GTM), this qualitative study used focus group and interview data to explore how both workers and clients’ experiences of the process of risk assessment and safety planning influenced the course of the intervention. What emerged is that workers and clients held similar representations about the social construction/collective representation of woman abuse and the work of CPS. For both worker and client participants the concept of ‘doing the right thing’ presented itself as an over-arching theme. This theme implies that there is a perceived ‘right way’ of addressing DV cases within CPS work and enhances understanding about the ways in which social workers and clients interact. These findings illustrate how narrative structures shape interactions that take place within the context of care and prevention, manifesting themselves in complex ways that can lead to misunderstanding the impact on children, the (un) conscious subjugation of women victims, and the absence of dialogue about the role of men in addressing DV at a system level.

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