published_or_final_version / abstract / Civil Engineering / Doctoral / Doctor of Philosophy

The prediction of motion of slowly moving landslides, also referred to as creeping slopes, is important for the reduction of landslide hazards. Such continuous and slowly moving landslides do not represent the usual stability problems of geotechnical analysis because these slopes are neither still nor ruptured but they move. For proper modeling of the motion of landslides, it is essential to develop improved techniques that integrate appropriate modeling of geological materials involved, laboratory and field tests, and verifications using computational methods. This dissertation focusses attention on the development of such an appropriate model for the time-dependent behavior of creeping landslides. Based on field observations it is proposed that the phenomenon of creeping landslides can be considered as involving the motion of a large mass of soil over a parent (fixed) mass with pronounced shear deformations occuring in a thin layer between the moving mass and the parent mass. The thin layer is refered to as interface zone while the overlying mass is refered to as solid body. The generalized Hierarchical Single Surface (HiSS) series of plasticity models are adopted to characterize the solid body. The interface zone is modeled using the specialization of the HiSS models for conditions occuring in the thin layer. Time dependency is introduced in constitutive models by adopting Perzyna's elastoviscoplastic formulation. The parameters for the HiSS and interface models are determined from laboratory tests on soils obtained from an actual slowly moving landslide at Villarbeney in Switzerland. Triaxial tests along various stress paths and oedemeter tests are conducted for the solid body. New analytical solutions are derived for prediction of oedometer tests. A general procedure for determination of viscous parameters is developed and techniques to process raw creep test data are proposed. Novel and representative simple shear interface tests are conducted to find parameters for the interface model. Special techniques for experimental analysis have been developed. A modified interface model to simulate the observed phenomenon of only compaction under shear is proposed. The parameters for the constitutive models are verified by numerically backpredicting experimental tests. An existing finite element code has been modified to incorporate various aspects of the small strain elastoviscoplastic formulation. Field measurements in the form of inclinometer profiles at various borehole locations on Villarbeney landslide are available. These inclinometer profiles are predicted using the proposed model. A comparison of the field measurements and the results from finite element analysis shows that such a model can be successfully used for predicting the behavior of slowly moving landslides.

Wong Wai Mei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 175-192). / Abstracts in English and Chinese. / Declaration --- p.ii / Acknowledgements --- p.iii / Abstract --- p.iv / Abbreviation --- p.vi / Table of Contents --- p.vii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Section I --- The Making of Genetically Modified Organisms --- p.2 / Chapter 1.1 --- Conventional breeding in agriculture --- p.2 / Chapter 1.2 --- What is genetic engineering? --- p.4 / Chapter 1.3 --- Plant transformation --- p.5 / Chapter 1.3.1 --- Agrobacterium-mediated --- p.6 / Chapter 1.3.2 --- Direct gene transfer --- p.8 / Chapter 1.3.2.1 --- Microparticle bombardment --- p.8 / Chapter 1.3.2.2 --- Protoplasts --- p.9 / Chapter 1.3.3 --- Gene silencing --- p.10 / Chapter 1.4 --- Examples of genetically modified crops --- p.13 / Chapter 1.5 --- Foreign genes commonly found in transgenic plants --- p.14 / Chapter Section II --- Benefits and Environmental Concern of GMOs --- p.17 / Chapter 2.1 --- Mechanism of GMO --- p.17 / Chapter 2.1.1 --- Herbicide tolerant crops --- p.18 / Chapter 2.1.2 --- Insect resistant crops --- p.19 / Chapter 2.1.3 --- Delayed ripening crops --- p.20 / Chapter 2.1.4 --- Virus resistant crops --- p.20 / Chapter 2.2 --- Benefits of GMOs --- p.21 / Chapter 2.3 --- Impact of GM foods to human health and the environment --- p.22 / Chapter 2.3.1 --- Human health --- p.22 / Chapter 2.3.1.1 --- GM potatoes --- p.23 / Chapter 2.3.1.2 --- CaMV risks? --- p.24 / Chapter 2.3.1.3 --- Food allergy --- p.25 / Chapter 2.3.2 --- Environmental concerns --- p.26 / Chapter 2.3.2.1 --- Horizontal gene transfer --- p.27 / Chapter 2.3.2.1.1 --- Selectable marker genes --- p.27 / Chapter 2.3.2.1.2 --- Herbicide resistant genes --- p.29 / Chapter 2.3.2.1.3 --- Insect resistant genes --- p.29 / Chapter 2.3.2.2 --- Ecology --- p.30 / Chapter 2.3.2.2.1 --- Monarch butterfly --- p.30 / Chapter Section III --- Future developments of GMO --- p.32 / Chapter 3.1 --- Designer Food and engineered plants --- p.32 / Chapter 3.1.1 --- Insect resistance --- p.33 / Chapter 3.1.2 --- Viral resistance --- p.33 / Chapter 3.1.3 --- Fungal resistance --- p.34 / Chapter 3.1.4 --- Nutritional quality --- p.34 / Chapter 3.1.5 --- Modifications of oil composition --- p.35 / Chapter 3.1.6 --- Medical applications --- p.37 / Chapter 3.1.7 --- Environmental applications --- p.40 / Chapter 3.1.7.1 --- Tolerance to high salinity and drought --- p.40 / Chapter 3.1.7.2 --- Tolerance to frost --- p.41 / Chapter 3.1.7.3 --- Bioremediation --- p.42 / Chapter 3.1.7.4 --- Biodegradable products --- p.43 / Chapter Section IV --- Regulation of GMO --- p.44 / Chapter 4.1 --- The question of labeling --- p.44 / Chapter 4.1.1 --- Moral and ethical issues --- p.44 / Chapter 4.1.2 --- Animal welfare --- p.45 / Chapter 4.2 --- International practice in GMO labeling --- p.46 / Chapter 4.2.1 --- United States of America --- p.46 / Chapter 4.2.2 --- Canada --- p.48 / Chapter 4.2.3 --- European Union --- p.49 / Chapter 4.2.4 --- Australia and New Zealand --- p.50 / Chapter 4.2.5 --- Japan --- p.51 / Chapter 4.2.6 --- Republic of Korea --- p.52 / Chapter 4.2.7 --- China --- p.53 / Chapter 4.2.8 --- Taiwan --- p.53 / Chapter 4.2.9 --- Hong Kong --- p.54 / Chapter Section V --- Uses of crops --- p.56 / Chapter 5.1 --- Uses of crops --- p.56 / Chapter 5.1.1 --- Soybean --- p.56 / Chapter 5.1.2 --- Corn --- p.57 / Chapter 5.1.3 --- Tomato --- p.58 / Chapter 5.1.4 --- Potato --- p.59 / Chapter 5.1.5 --- Rice --- p.60 / Chapter 5.1.6 --- Rapeseed --- p.61 / Chapter 5.1.7 --- Oil --- p.62 / Chapter 5.2 --- "Food additives, hormones and flavourings" --- p.63 / Chapter Chapter 2 --- Materials & Methods --- p.65 / Chapter 2.1 --- Materials --- p.66 / Chapter 2.1.1 --- Growth media & agar --- p.66 / Chapter 2.1.2 --- Reagents for agarose gel electrophoresis --- p.67 / Chapter 2.1.3 --- Reagents for preparation of competent cells --- p.67 / Chapter 2.1.4 --- Reagents for measurement of DNA concentration --- p.68 / Chapter 2.1.4.1 --- Measurement of DNA concentration by PicoGreen --- p.68 / Chapter 2.1.5 --- Reagents for Southern hybridization --- p.68 / Chapter 2.2 --- Methods --- p.70 / Chapter 2.2.1 --- Restriction endonuclease digestion --- p.70 / Chapter 2.2.2 --- Agarose gel electrophoresis of DNA --- p.70 / Chapter 2.2.3 --- DNA recovery from agarose gel --- p.71 / Chapter 2.2.3.1 --- QIAquick® gel extraction --- p.71 / Chapter 2.2.4 --- Ligation of purified DNA fragment into vector --- p.72 / Chapter 2.2.5 --- Transformation --- p.72 / Chapter 2.2.6 --- Rubidium chloride method for making competent cells --- p.12 / Chapter 2.2.7 --- Plasmid DNA preparation --- p.73 / Chapter 2.2.7.1 --- Concert Rapid Mini Prep --- p.73 / Chapter 2.2.7.2 --- QIAprep® Miniprep --- p.74 / Chapter 2.2.8 --- Extraction of plant genomic DNA --- p.75 / Chapter 2.2.8.1 --- Qiagen DNeasy´ёØ Plant Mini Kit --- p.75 / Chapter 2.2.9 --- Southern Hybridization --- p.75 / Chapter 2.2.9.1 --- Denaturation --- p.76 / Chapter 2.2.9.2 --- Blot transfer --- p.76 / Chapter 2.2.9.3 --- Pre-hybridization --- p.77 / Chapter 2.2.9.4 --- Synthesis of radiolabelled probe --- p.77 / Chapter 2.2.9.5 --- Hybridization of radiolabelled probe on filter --- p.77 / Chapter 2.2.9.6. --- Detection of hybridized probes --- p.78 / Chapter 2.2.10 --- Measurement of DNA concentration --- p.78 / Chapter 2.2.10.1 --- Determination of DNA on EtBr stained gel --- p.78 / Chapter 2.2.10.2 --- Determination of DNA by UV spectrophotometer --- p.78 / Chapter 2.2.10.3 --- Determination of DNA by PicoGreen --- p.79 / Chapter 2.2.11 --- DNA sequencing --- p.80 / Chapter 2.2.11.1 --- Automated sequencing by ABI Prism 377 --- p.80 / Chapter Chapter 3 --- PCR Diagnostics --- p.81 / Chapter 3.1 --- Applications of PCR to processed foods --- p.82 / Chapter 3.1.1 --- DNA quality --- p.82 / Chapter 3.1.2 --- PCR & Multiplex PCR --- p.83 / Chapter 3.1.3 --- Choice of primers --- p.84 / Chapter 3.1.4 --- Inhibitors --- p.84 / Chapter 3.2 --- Materials & Methods --- p.85 / Chapter 3.2.1 --- Selection of primers --- p.85 / Chapter 3.2.2 --- Amplification of target sequences --- p.86 / Chapter 3.2.3 --- Multiple amplification of target sequences --- p.87 / Chapter 3.3 --- Results --- p.88 / Chapter 3.4 --- Discussion --- p.93 / Chapter Chapter 4 --- Quality Control in GMO detection --- p.95 / Chapter 4.1 --- Standardization of pre- and post- PCR analysis --- p.96 / Chapter 4.1.1 --- General guidelines --- p.96 / Chapter 4.1.2 --- UV irradiation --- p.97 / Chapter 4.1.3 --- Inactivation protocols --- p.93 / Chapter 4.1.4 --- Positive and negative controls --- p.99 / Chapter 4.1.5 --- PCR verification --- p.99 / Chapter 4.1.6 --- Equipment decontamination --- p.100 / Chapter 4.2 --- Materials & Methods --- p.101 / Chapter 4.2.1 --- Selection of primers for external control --- p.101 / Chapter 4.2.2 --- Development of the external control --- p.101 / Chapter 4.2.3 --- Selection of primers for internal control --- p.103 / Chapter 4.3 --- Results --- p.104 / Chapter 4.4 --- Discussion --- p.107 / Chapter Chapter 5 --- DNA extraction from food samples --- p.110 / Chapter 5.1 --- Introduction --- p.111 / Chapter 5.2 --- Reagents and Buffers for DNA extraction from food samples --- p.112 / Chapter 5.2.1 --- Cetyltrimethylammonium bromide (CTAB) extraction method --- p.112 / Chapter 5.2.2 --- Organic-based extraction method --- p.113 / Chapter 5.2.3 --- Potassium acetate/sodium dodecyl sulphate precipitation method --- p.113 / Chapter 5.2.4 --- Hexane-based extraction method --- p.114 / Chapter 5.3 --- Weight and names of samples --- p.115 / Chapter 5.4 --- DNA extraction methods --- p.115 / Chapter 5.4.1 --- CTAB extraction method --- p.115 / Chapter 5.4.2 --- Qiagen DNeasy´ёØ plant mini kit --- p.116 / Chapter 5.4.3 --- Promega Wizard® genomic DNA purification --- p.116 / Chapter 5.4.4 --- Promega Wizard® Magnetic DNA purification system --- p.117 / Chapter 5.4.5 --- Promega Wizard® DNA Clean-Up system --- p.118 / Chapter 5.4.6 --- Qiagen QIAshreddrer´ёØ and QIAamp spin column --- p.119 / Chapter 5.4.7 --- Chelex-based extraction method --- p.119 / Chapter 5.4.8 --- Organic-based extraction method --- p.120 / Chapter 5.4.9 --- Nucleon PhytoPure extraction and purification method --- p.120 / Chapter 5.4.10 --- Potassium acetate/SDS precipitation method --- p.121 / Chapter 5.4.11 --- Hexane-based extraction method --- p.122 / Chapter 5.5 --- Results --- p.123 / Chapter 5.5.1 --- Comparison of eleven extraction methods --- p.123 / Chapter 5.5.2 --- Comparison of DNA extraction on selected methods --- p.125 / Chapter 5.6 --- Discussion --- p.132 / Chapter Chapter 6 --- Quantitative Analysis --- p.136 / Chapter 6.1 --- Introduction --- p.137 / Chapter 6.1.1 --- Chemistry of quantitative PCR --- p.138 / Chapter 6.1.2 --- PCR system --- p.140 / Chapter 6.2 --- Materials & Methods --- p.142 / Chapter 6.2.1 --- Design of primers and probes --- p.142 / Chapter 6.2.2 --- Methods --- p.145 / Chapter 6.3 --- Results --- p.146 / Chapter 6.3.1 --- Selection of primer/probe --- p.146 / Chapter 6.3.2 --- Primer optimization --- p.149 / Chapter 6.3.3 --- Quantitative analysis of real samples --- p.158 / Chapter 6.4 --- Discussion --- p.152 / Chapter Chapter 7 --- Conclusion --- p.168 / References --- p.175 / Appendix --- p.193

S.B. Gershwin, J.G. Kimemia, E.R. Ducot. / Bibliography: leaf [5] / "August 1981" / "National Science Foundation Grant DAR78-17826"

The main purpose of Structural Health Monitoring (SHM) is the assessment of structural conditions in aerospace, mechanical and civil systems. In structural engineering, damage is defined as any permanent change in the structural and geometric properties of a system caused by an external action. Vibration-based damage assessment methods rely on the use of sensors that record the structural dynamic response of a system that is determined by its structural and geometric properties. External disturbances and environmental conditions in which the system operates cause fluctuations of these properties and might hide the change in signature induced by damage. To handle the uncertainties in the determination of the structure’s characteristics, a statistical pattern recognition approach is presented in this thesis. Any statistical approach relies on the statistics of some features that provide a compact representation of the structural properties and that are sensitive to damage. Such features are called damage sensitive features and are extracted from the dynamic response of the structure: their statistical distribution is then analyzed to assess the occurrence of damage. This dissertation focuses on the analysis of the statistical distribution of damage sensitive features which are extracted through parametric and nonparametric algorithms. Cepstral coefficients are features defined in the field of acoustics and, in this thesis, they have been adapted to SHM analyses in order to develop compact damage sensitive features whose extraction requires a low computational effort. In this thesis, cepstral coefficients have been mathematically transformed through a Principal Component Analysis in order to generate damage sensitive features that are barely sensitive to measurement noise, environmental conditions and different excitation sources. In an attempt to develop an automated strategy for structural damage assessment, the search for damage sensitive features has been extended to the estimation of structural mode characteristics obtained through an output-only version of the Inner Product Vector methodology, e.g. considering only the structural response time histories. This new damage assessment procedure requires low computational effort and is capable to identify both the presence of damage and its location. However, one of the critical points of the proposed procedure consists in the manual evaluation of the spectral content of the dynamic responses that requires the user’s intervention. To automatize this procedure, a Bayesian clustering algorithm and a classifier have been successfully implemented and tested. Finally, the robustness of Bayesian regression algorithms to overfitting led us to consider their applicability to the field of system identification in order to provide a reliable estimate of the structural modal parameters that can be used as damage sensitive fea- tures. In fact, one of the main problems of system identification algorithms is that they rely on a regression algorithm that tends to overfit data producing unreliable results. Results provided by the Bayesian regression based system identification algorithm are obtained and compared with the ones coming from standard system identification algorithms.

In recent years, experiments have been carried out to evaluate the performance of water-filled cushion cells used to attenuate energy of automobile collisions. The water-filled cushion cell is a vinyl plastic cylinder of 6 inches nominal outside diameter, 1/4 inch wall thickness, 40 inches length, closed at the bottom by a cast-in-place vinyl plug and partially closed by a bolted-in vinyl diaphragm at the upper end. These cells are designed to be installed in the path of a crashing automobile to absorb and dissipate the kinetic energy of impact. Properly designed cushions could be used as one means of saving life and property.

The purpose of this research project was to better understand the experiences of graduate students in internationally diverse research groups, and how these research groups and international diversity contributes to a student's intent to complete his or her graduate degree. This exploratory mixed methods research was conducted in three phases: (1) an ethnographic study of selected research groups in two engineering graduate departments, (2) development of a survey for students in graduate engineering students, and (3) administering the survey to graduate engineering students in research groups to verify the findings. In order to address the project aims, three smaller studies were initiated that address individual elements of graduate education, including: learning in research groups and international diversity, and retention in graduate engineering programs. The focus of the first study was to understand how and under what conditions research groups foster successful learning and professional development for graduate engineering students, and how these findings can be used to inform management of engineering research groups to optimize student learning, productivity, and intent to complete the degree. Key findings from the ethnographic analysis indicate that group size directly influences the mechanisms of student learning, as well as several elements common across research groups from different universities and academic departments, including: power distance and communication, access to resources, and role of the advisor. During the (second) integration phase of this mixed methods study, the nine months of ethnographically guided observations and interviews were used to develop a survey examining graduate engineering student retention. Findings from the ethnographic fieldwork yielded several themes, including: the role of international diversity, research group organization and climate, student self efficacy, and individual and group learning experiences. Final retention themes from the ethnographic analysis are presented along with a discussion of how these data were configured into instrument questions. A discussion of the final instrument is presented, including validity and reliability analysis, and how the final questions were integrated into themes to test hypotheses for future studies. This chapter also presents implications for mixed methods researchers interested in using qualitative methods to create new instruments. In the third and final stage of the research study, the survey developed in the second phase of the research study was administered to four universities across the United States. Data analysis focused on better understanding the differences in retention constructs by student nationality. Results from more than 600 engineering PhD students from 6 international regions enrolled in U.S. engineering graduate programs were examined to characterize demographic differences in participant responses for intention to complete the degree. Six constructs were found to be significant in predicting students' responses regarding their intention to complete their degree, including: expectations, climate, organization, project ownership, perception of value, and individual preferences. Taken together these constructs were able to explain 28 percent of the variation in student responses. Additionally, all six constructs showed significant differences with respect to a respondent's country or region or origin. These results are discussed in light of the implications for faculty members advising similarly diverse groups of students. In combination, these three studies represent a sequential exploratory mixed methods approach in which ethnographically guided observations and interviews were integrated into a quantitative instrument. Results of this study can be used to inform the organization and management of internationally diverse research groups to foster student development and ultimately increase retention. / Ph. D.

Location â allocation models are designed to seek the concurrent location of a set of service facilities and an allocation scheme to satisfy the demands of a set of customers or users of a given system. If the location-allocation model is based on a graph-theoretic formulation, then the demand-fulfilling items will move from a designated origin or origins, through arcs and transshipment nodes, to a set of destinations selected by the model. It is suggested in this research effort that such a modeling structure may be employed to simulate transportation evacuation conditions that may arise in the case of a natural disaster, namely a hurricane. A nonlinear mixed integer mathematical program is formulated to route passengers in automobiles on paths in the transportation network, such that the endangered area is evacuated in the minimum amount of time. One heuristic and two exact, convergent, implicit enumeration algorithms based on the generalized Benders' decomposition method are presented. The algorithms are designed to exploit the inherent problem structure. Computational experience is provided against a set of realistic test problems formulated on the Virginia Beach network. Potential avenues for further research are also explored. / Master of Science

User-System Interface (USI) design is a highly iterative process involving empirical testing and evaluation. The existence of a design specification is implicit in this design process. The quality of the design specification impacts the length and cost of the design cycle. A survey was made of available USI specification tools to determine: which USI components they can specify; their relation to a finite state model of the USI; and if they are usable by the human factors engineer as a basis for an analytic analysis of a USI design to detect violations of excepted USI design guidelines. Four categories of tools were surveyed: semi-formal techniques, Backus-Naur Form grammars, programming languages, and transition networks. An engineering tradeoff analysis was performed based on four pragmatic criteria: understandability, efficiency, expressive power, and fidelity. The results of the tradeoff analysis suggest that specification tools differ in representational strength and it is best to use a set of tools for a complete specification. A behavioral study using human factors engineers was performed to validate the results of the tradeoff analysis. Human factors graduate students were trained in the use of one of three specification tools and asked to perform an analytic analysis looking for design defects. Fifteen design defects were embedded in each of the specifications. Results suggest that using two of the tools together is the most effective specification technique. In light of these results, current and future software design practices were examined to determine what role the human factors engineer can have on the design team. / Master of Science

M.S.