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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.
21

Construction of Horizontal Wells in Municipal Solid Waste using a Directional Drill

Ho, Pei-Yi Joy 14 September 2007 (has links)
Horizontal directional drilling (HDD) has been employed in many situations including cable lines under rivers and rehabilitation of pipelines under buildings and busy traffic. Within the context of a municipal landfill site, a by-product of organic waste (leachate) accumulates within an established landfill. Leachate is a liquid produced from the wastes placed inside landfills and rain that percolates through the wastes and reacts with the products of decomposition. This thesis investigates the effectiveness of employing HDD techniques to extract leachate in the municipal landfill application.
22

Ring Laser Integrated Taper-directional Coupler Using Deep Etching to Fabricate Total Internal Reflection Mirrors

Chen, Po-Cheng 09 September 2010 (has links)
The goal of the thesis is Ring Laser Integrated Taper-directional Coupler Using Deep Etching to Fabricate Total Internal Reflection Mirrors. In order to total internal reflection, we make deep etching for the total reflection mirror. We use the tapered waveguide coupler, if unidirectional traveling-wave oscillation can be achieved, spatial hole burning effects seen in DFB laser can be avoided. In this paper, two types of ring laser structures are fabricated and discussed, in which (1) 90 degrees total reflection mirrors and (2) circular retro-mirrors. In fabrication process, we get smooth waveguide and highly perpendicularity waveguide by Self-Alignement wet etch method. In order to reduce bending loss and waveguide loss, we make deep etching for the total reflection mirror and circular retro-mirrors.
23

Analysis of WACSIS data using a directional hybrid wave model

Zhang, Shaosong 25 April 2007 (has links)
This study focuses on the analysis of measured directional seas using a nonlinear model, named Directional Hybrid Wave Model (DHWM). The model has the capability of decomposing the directional wave field into its free wave components with different frequency, amplitude, direction and initial phase based on three or more time series of measured wave properties. With the information of free waves, the DHWM can predict wave properties accurately up to the second order in wave steepness. In this study, the DHWM is applied to the analyses of the data of Wave Crest Sensor Inter-comparison Study (WACSIS). The consistency between the measurements collected by different sensors in the WACSIS project was examined to ensure the data quality. The wave characteristics at the locations of selected sensors were predicted in time domain and were compared with those recorded at the same location. The degree of agreement between the predictions and the related measurements is an indicator of the consistency among different sensors. To analyze the directional seas in the presence of strong current, the original DHWM was extended to consider the Doppler effects of steady and uniform currents on the directional wave field. The advantage of extended DHWM originates from the use of the intrinsic frequency instead of the apparent frequency to determine the corresponding wavenumber and transfer functions relating wave pressure and velocities to elevation. Furthermore, a new approach is proposed to render the accurate and consistent estimates of the energy spreading parameter and mean wave direction of directional seas based on a cosine-2s model. In this approach, a Maximum Likelihood Method (MLM) is employed. Because it is more tolerant of errors in the estimated cross spectrum than a Directional Fourier Transfer (DFT) used in the conventional approach, the proposed approach is able to estimate the directional spreading parameters more accurately and consistently, which is confirmed by applying the proposed and conventional approach, respectively, to the time series generated by numerical simulation and recorded during the WACSIS project.
24

Space division multiple access systems : computational electromagnetic studies of the physical and network layers /

Dandekar, Kapil Ramesh, January 2001 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 129-135). Available also in a digital version from Dissertation Abstracts.
25

Detection of scattered ambient noise by fish : possible passive perception of potential predators and prey from palpable pressure and particle path perturbations

Lewis, Thomas N. 08 1900 (has links)
No description available.
26

Mechanistic modeling of cuttings transport in directional wells /

Campos, Wellington. January 1995 (has links)
Thesis (Ph.D.)--University of Tulsa, 1995. / Includes bibliographical references (leaves 67-70).
27

Correlations for drill-cuttings transport in directional-well drilling /

Becker, Thomas Edward. January 1987 (has links)
Thesis (Ph.D.)--University of Tulsa, 1987. / Page xv lacking. Bibliography: leaves 150-154.
28

Voltage gated ion channels shape subthreshold synaptic integration in principal neurons of the medial superior olive

Mathews, Paul James, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.
29

Geological hazards affecting horizontal directional drilled installations in Hong Kong

Barriera, Antonio Jose. January 2003 (has links)
Thesis (M. Sc.)--University of Hong Kong, 2003. / Also available in print.
30

Optimizing front/back confusion rates in sound localization performance : cluster analyses and experimental studies /

Ngan, Kwok Hung. January 2005 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Accompanying CD-ROM contains supporting information. Includes bibliographical references (leaves 153-156). Also available in electronic version.

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