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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.
1011

Evaluating Environmental Impact Assessment of a local land use plan : a case study of the City of Elk Grove’s general plan EIRs

Jung, Seung Hoon 04 December 2013 (has links)
Many planners and researchers pay attention to the potentials of Environmental Impact Assessment (EIA) as a planning method. The EIA of a local land use plan or comprehensive plan becomes effective under the Mini-NEPA or State Environmental Policy Act. In this context, this study focuses on the NEPA based EIA of local land use plans in order to examine its effectiveness as part of the planning process. Based on the assumption that systematic environmental assessment will ensure the effectiveness and the quality of a local land use plan, this study evaluate a local land use plan EIA process of California with the quality and effectiveness criteria. / text
1012

Analysis of air-coupled system for exciting and sensing stress waves in concrete

Tsai, Yi-Te 01 July 2014 (has links)
Nondestructive testing (NDT) plays a more important role today in evaluating structural integrity of civil infrastructure. Impact-echo method (IE) is an effective stress wave based NDT method for locating defects in concrete structures. However, the contact requirement between sensor and concrete surface significantly limits the test speed and wide application of this method to large-scale structures such as bridges. Recent studies show the feasibility of air-coupled sensing, which eliminates the contact requirement and thus accelerates IE test. To further improve the test speed, a fully non-contact IE test using air-coupled sensing and excitation is investigated in this dissertation. This dissertation provides the theoretical basis required for developing an effective air-coupled IE method. For air-coupled sensing, 2D numerical simulations are first conducted to study the wave propagation in the air-solid system during IE tests. Visualized wavefield indicates that parabolic reflectors can effectively enhance the IE signal strength by focusing airborne IE waves to an air-coupled sensor. To maximize signal amplification, an analytical solution for the focused axial pressure response of a parabolic reflector with incident plane waves is derived. This solution is used to determine the reflector geometry that gives the highest focusing gain. For air-coupled excitation, a focused spark source with an ellipsoidal reflector is employed to excite stress waves in concrete. Numerical simulations and available nonlinear computer code (KZKTexas) are employed to investigate the reflector geometry that gives the highest stress wave excitation in solids. An acoustical muffler that works with the focused spark source is proposed to decrease the spark-induced noise level. The effect of source receiver spacing on received IE signals is studied. Simulated wavefield demonstrates that the mode shape of IE surface displacement distribution along the radial direction matches the Bessel function of the first kind (J0). Numerical 3D simulation results show the relation between focused IE signals and source receiver spacings, and indicate the spacing should be minimized to obtain better focused IE signal strength. Air-coupled IE test using through transmission setup is also investigated. / text
1013

Development of a non-contact ndt system for stress wave sensing and excitation

Dai, Xiaowei 15 January 2015 (has links)
Non-destructive testing (NDT) plays an important role today in condition assessment of civil infrastructure. Among these NDT methods, the Impact-Echo (IE) method is widely used to determine the thickness of a plate structure and locate delaminations in concrete. The conventional IE test uses a contact impact source and a contact sensor, which limits the scanning speed. Recent studies show the feasibility of applying the air-coupled sensing technology to the IE test. With the contact requirement eliminated, a fully air-coupled NDT system can be realized to achieve rapid scanning on large scale structures. In this dissertation, the air-coupled IE test is first simulated using 2D finite element models. The numerical simulation results are validated by experimental measurements. It is shown that the airborne IE mode is a quasi-plane wave in air. A parabolic reflector is proposed to focus the airborne IE wave and amplify the air-coupled IE test signals. The focusing effect is validated by experimental results. By applying a parabolic reflector to the air-coupled sensor, it is found that large sensor lift-off height and source-receiver spacing can be used in the air-coupled IE test. The geometry of the parabolic reflector and source-receiver spacing are optimized using numerical simulations. A focused spark source is proposed as a non-contact source for the fully air-coupled test system. The spark source is first calibrated in an anechoic chamber. The feasibility of using the focused spark source for stress wave excitation is validated by experiments. A fully air-coupled testing system is realized by combining the air-coupled sensor and the air-coupled source. Experimental studies show that this system can measure surface wave and the IE mode. The fully air-coupled system is tested using a conventional IE test setup and a through transmission test setup. An acoustic muffler is introduced to suppress the acoustic noise from the spark source. Several advanced signal processing techniques to reduce the acoustic noises are also investigated. The air-coupled sensor has been adopted on a crawler NDT system for concrete inspection in a noisy field environment. / text
1014

Hamilton's equations with Euler parameters for hybrid particle-finite element simulation of hypervelocity impact

Shivarama, Ravishankar Ajjanagadde 28 August 2008 (has links)
Not available / text
1015

Impact assessment of non-native parasites in freshwater fisheries in England and Wales

Williams, Chris F. January 2007 (has links)
Non-native parasites pose a significant threat to aquatic bio-diversity and fishery development. Many factors have facilitated the introduction of non-native parasites into England and Wales. Identifying the effects of these parasites and the importance of any changes to wild fish populations represents a considerable challenge. However, in order for the Environment Agency to identify future disease threats, effectively manage resources and implement practical and sustainable control measures, the risks posed by these parasites to fisheries must be better understood. A structured, risk-assessment process for non-native freshwater parasites is proposed. This approach includes procedures for hazard identification, impact assessment, risk management and communication. A quantitative approach to hazard identification provides an initial prediction of impact at the time of introduction to inform decisionmaking and guide preliminary control measures. This is followed by a more comprehensive framework for impact assessment that promotes understanding of changes at host, population and fishery levels. These are placed into context with the economic and ecological value of native resources. An independent 'non-native parasite review group' has been convened to ensure consistency of policy decisions and clear communication of disease risks to interested bodies. It is hoped that this wil assist the management of future invasions and provide a scientifically robust foundation on which to base proportionate control measures. The Category 2 parasites are defined as "species having a significant disease potential when introduced into waters where they do not already exist, or are non-indigenous species with unknown pathogenicity and distribution". Understanding of the dangers posed by these parasites varies considerably. Ergasilus sieboldi, Anguilicola crassus, Bothriocephalus acheilognathi and Lernaea cyprinacea, are well recognised non-native fish pathogens that pose a considerable threat to fisheries. Conversely, the effects of other introduced parasites remain poorly understood. In many cases, a paucity of published literature at the time of introduction has limited a reliable assessment of impact. Four non-native parasites were considered a priority for further study. These were Paraergasilus longidigitus (Copepoda: Poecilostomatoida), Ergasilus briani (Copepoda: Caryophylldae) Poecilostomatoida ), Atractolytocestus huronensis (Cestoda: and Philometroides sanguinea (Nematoda: Philometridae). Pathological, epidemiological and experimental investigations were undertaken to assess the effects of these parasites at host and population levels. P. longidigitus can cause pronounced pathological changes to the olfactory epithelium of infected fish. Although this damage provides the potential for disruption to spawning through reduced sensitivity to reproductive chemical cues, experimental observations combined with seasonality studies suggest that the parasite is unlikely to disrupt reproduction within infected cyprinid fisheries. Similarly, studies conducted on the caryophylidean cestode A. huronensis provide little evidence to suggest that the parasites poses a threat to car fisheries. Damage within the intesinal tract was characterised by relatively mild mechanical and inflammatory changes. Infections of up 213 parasites had no adverse affect upon the conditon of common carp. Based on these findings and the application of the aformentioned risk model, P. longidigitus and A. huronensis are considered to be of low disease risk to fisheries. The pathology of E. briani and P. sanguinea are described for the first time. Literature suggests that both parasites are pathogenic to juvenile fIsh. E. briani causes a number of pathological changes within the gils of juvenile cyprinids, although these remain localised due to the very strict site specificity of the parasite. Migrations of the nematode P. sanguinea causes damage to the fins and caudal musculature of juvenile crucian car. For both parasites, the extent and severity of pathological changes are inversely proprtional to host size. Further studies at the population level are needed before an assessment of impact to fisheries can be made. The difficulties associated with studying the effects of introduced parasites to juvenile fish populations in the wild are recognised. Recommendations for further study are given.
1016

Positional Awareness Map 3D (PAM3D)

Hoffman, Monica, Allen, Earl, Yount, John, Norcross, April 10 1900 (has links)
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / The Western Aeronautical Test Range of the National Aeronautics and Space Administration's Dryden Flight Research Center needed to address the aging software and hardware of its current situational awareness display application, the Global Real-Time Interactive Map (GRIM). GRIM was initially developed in the late 1980s and executes on older PC architectures using a Linux operating system that is no longer supported. Additionally, the software is difficult to maintain due to its complexity and loss of developer knowledge. It was decided that a replacement application must be developed or acquired in the near future. The replacement must provide the functionality of the original system, the ability to monitor test flight vehicles in real-time, and add improvements such as high resolution imagery and true 3-dimensional capability. This paper will discuss the process of determining the best approach to replace GRIM, and the functionality and capabilities of the first release of the Positional Awareness Map 3D.
1017

Social Assessment of Siting a Low-Level Radioactive Waste Storage Facility in Michigan

Stoffle, Richard W., Traugott, Michael J., Stone, John V., McIntyre, Paula Drury, Davidson, Carla C., Jensen, Florence V., Coover, Gail E. January 1990 (has links)
This report presents findings from a social assessment of siting a low­ level radioactive waste storage facility in Michigan. The research focused specifically on how people perceive themselves to be affected by the proposed facility and the degree of community support for and opposition to the facility. Social assessment research in the LLRW project consisted of a telephone survey of Michigan residents and an in-depth ethnographic survey of residents in the tri-state area of Michigan, Indiana and Ohio. Findings from these studies can aid in the development and implementation of a social monitoring program and in the design of community-based measures to mitigate unwanted social impacts.
1018

Pah hu wichi (From Big Spring Running Down): Big Spring Ethnographic Assessment US 95 Corridor Study

Stoffle, Richard W., Pittaluga, Fabio, Earnest, Tray G., Eisenberg, Amy, Amato, John, Dewey-Hefley Genevieve 09 1900 (has links)
It was determined in the mid- 1990s that Highway 95 in southern Nevada had experienced a tremendous increase in traffic and increased safety hazards for motorists due to growth in population and commerce in the Southwest. Federal, state, and local governments worked to find a solution to the impacts of increased traffic and have chosen a number of alternatives related to highway expansion. This is an American Indian ethnographic study for the Big Springs Highway 95 Corridor Project. The study area included the Big Spring Complex and associated American Indian sites potentially impacted by the westward expansion of U.S. 95 north of its junction with U.S. 15. The study does not include an analysis of U.S. 95 impacts to the east of the Big Springs complex towards what is known as Lorenzi Park. This report is based on interviews with American Indian representatives from six Southern Paiute tribes and the Las Vegas Indian Center. Each tribe and organization chose to send one or more tribal members to evaluate the potential impacts to American Indian cultural resources that would occur if Highway 95 were to be expanded to incorporate a portion of the current Big Spring location. This report provides the Southern Paiute evaluations of the proposed expansion.
1019

An ecological assessment of Impatiens glandulifera in its introduced and native range and the potential for its classical biological control

Tanner, Rob January 2012 (has links)
No description available.
1020

Norse landnám and its impact on the vegetation of Vatnahverfi, Eastern Settlement, Greenland

Ledger, Paul M. January 2013 (has links)
No description available.

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