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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.
161

Population enumeration and the effects of oil and gas development on dune-dwelling lizards

Smolensky, Nicole Limunga 15 May 2009 (has links)
Habitat loss is one of the leading causes of species decline across all taxa and conservation practices require information on population trends. The Mescalero Sands ecosystem, New Mexico, USA, is experiencing landscape changes associated with oil and gas development. The dune-dwelling lizard community contains a habitat specialist, Sceloporus arenicolus, that is of particular interest because it has a very limited geographic distribution that is entirely subject to oil and gas development. Distance sampling is widely used to estimate population densities of many vertebrate taxa however assumptions can be difficult to satisfy with certain species or in certain habitats. Researchers must investigate the likelihood that assumptions can be satisfied before implementing any population sampling method. I had two objectives. First to investigate the precision of population densities of dune-dwelling lizards estimated via distance sampling that was coupled with double-observer surveys. Second to compare abundances of dune-dwelling lizards among sites that varied in oil and gas development. I conducted distance line transects and compared those density estimates to densities obtained from total removal plots. I quantified the amount of oil and gas development, habitat quantity and quality and correlated those to lizard abundances to investigate the effects of oil and gas development on lizard populations. I found large differences in density estimates from distance sampling and total removal plots that resulted from violation of distance sampling assumptions. Although distance sampling is a low cost method, it does not produce reliable density estimates for dune-dwelling lizards and is not an appropriate sampling method in this system. I did not find oil and gas development effects on the habitat quantity, quality or on the abundances of lizards. Lizard abundances were most strongly correlated to habitat quantity. Lizard abundances may be influenced by complex interactions between oil and gas development and habitat quantity and quality but controlling for those interactions was beyond the scope of my study. Before and after experiments and long-term studies at multiple sites would be required to more fully address the effects of oil and gas development on lizard populations in the Mescalero Sands.
162

Development of Autonomous Shallow Water Acoustic Logger

Yen, Chia-You 27 July 2003 (has links)
The sonobuoy originated from military submarine detection¡Ait was also used to measure ocean acoustic signal by scientists¡Abut the continuous recording and transmitting design by early sonobuoy is not suitable for long-term or scheduled observations. In this research¡A¡§off the self¡¨ components were integrated to develop an autonomous sonobuoy¡Awhich can be used to measure shipping noise and marine life acoustic signal in coastal water. The electronic design is based on a PC motherboard¡Ait is currently configured with a maximum sampling rate of 44.1 kHz¡Aand a maximum storage capacity of 40 GB. The sound was collected by a plug and play hydrophone system¡Awhich is controlled by a program written by LabVIEW. In addition to the programmable data acquisition and low cost advantages¡Athe flexible design allows quick system expansion and adjustment¡Ait can also be configured to record from multiple transducers.
163

An improved wetted-wall bioaerosol sampling cyclone

Phull, Manpreet Singh 30 October 2006 (has links)
A modified wetted-wall cyclone using different methods of water injection techniques upstream of the inlet was designed as an improvement to a wetted-wall cyclone developed by White, which uses liquid injection through a port on the wall of the cyclone inlet. The new cyclone has a high aerosol sampling flow rate (1250 L/min) and maintains constant cut-point with the modified White-type cyclone along with greater collection efficiency, lower time response, and reduced pressure drop. The final air-blast atomizer cyclone (AAC2.1a) design considered has an aerosol-tohydrosol collection efficiency cut-point of 1.3 mm with collection efficiencies at 1 and 2 mm of 39.9% and 86%, respectively. The efficiency reported for the modified White-type cyclone for particle sizes of 1 and 2 mm was 40.5% and 76.3%, respectively, under no water bypass conditions. The aerosol-to-aerosol transmission efficiency for the AAC2.1a configuration was found to be approximately 53.7% for 1 mm diameter particles as compared with 67.2% for the modified White-type cyclone. Dry and wet time response tests were performed in which the modified White-type cyclone had an initial response of 2.5 minutes for a wet start and 1 minute for a dry start for a condition where there was no liquid carryover through the cyclone outlet. The rise time for AAC2.1a cyclone under dry and wet start conditions was 0.5 minutes and 1.3 minutes, respectively. The decay response of the modified White-type cyclone was 1.1 minutes for a wet start and 1.2 minutes for a dry start. The corresponding numbers for AAC2.1a cyclone were 1.4 minutes for a dry start and 1 minute for a wet start condition. Off design tests were run at approximately ±10% air flow rates to see the effect on cyclone performance. It was seen that at a 10% higher flow rate (1350 L/min) the efficiency was 54.3%. At a 10% lower flow rate (1125 L/min) the efficiency was 33.7% as compared with an efficiency of 39.9% at 1250 L/min for 1.0 mm PSL particles. It was found that at a water input of 0.8 mL/min the efficiency reduced to 79.3% as compared to 86% at an input flow rate of 1.6 mL/min for 2 mm size PSL.
164

A comparison of basal area and merchantable height as auxiliary variables for double sampling with point sampling

Bailes, Wesley Wayne, January 2004 (has links)
Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xi, 116 p. : ill. (some col.), col. maps. Vita. Includes abstract. Includes bibliographical references (p. 55-56).
165

Life insurance sales representative

Peterson, Carl E. January 2001 (has links) (PDF)
Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2001. / Includes bibliographical references.
166

Improving sampled microprocessor simulation

Luo, Yue 28 August 2008 (has links)
Not available / text
167

Estimating population size for capture-recapture/removal models with heterogeneity and auxiliary information

Xi, Liqun., 奚李群. January 2004 (has links)
published_or_final_version / abstract / toc / Statistics and Actuarial Science / Doctoral / Doctor of Philosophy
168

Some practical issues in estimation based on a ranked set sample

譚玉貞, Tam, Yuk-ching. January 1999 (has links)
published_or_final_version / Statistics / Master / Master of Philosophy
169

Statistical analysis for capture-recapture experiments in discrete time

尹再英, Wan, Choi-ying. January 2001 (has links)
published_or_final_version / Statistics and Actuarial Science / Master / Master of Philosophy
170

THE DESIGN AND APPLICATION OF A POLAR NEPHELOMETER FOR AEROSOL STUDIES

Hansen, Mark Zabel, 1948- January 1977 (has links)
No description available.

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