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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.
321

Numerical investigation of baroclinic tides in the Red Sea

Guo, Daquan 04 1900 (has links)
Baroclinic tides play a significant role in driving deep-ocean mixing, which not only influences the transport of nutrients and other biological tracers, but also affects the large scale circulations. This thesis combines advanced numerical modeling techniques and available observations to investigate the characteristics of baroclinic tides in the Red Sea, and understand their formation and fate, and their influence on the circulation and ecosystem. Based on a validated 3D, non-hydrostatic and high-resolution MIT General Circulation Model (MITgcm), we first established four potential areas for the generation of baroclinic tide in the Red Sea: the Strait of Bab-el-Mandeb (BAM), the southern Red Sea, the Gulf of Suez, and the Strait of Tiran. These areas are consistently suggested by the spatial distribution of baroclinic tidal kinetic energy and energy fluxes. The majority of the baroclinic energy disappears within the basin; either dissipates due to friction and bottom drag or converts back into barotropic energy due to pressure. We next conducted 2D numerical simulations to investigate the generation mechanism behind the formation of the observed internal solitary waves(ISWs) in the southern Red Sea, revealing the dominant role of tide-topography interactions. Instead of evolving from the disturbed thermocline due to a locally impinging tidal beam ISWs are generated from the depression formed near the shelf. As this depression propagates out of the shelf, it gradually steepens and ultimately breaks into a group of ISWs. To further study the breaking and dissipation processes of the ISWs, we implemented a regional high-resolution MITgcm for the southern Red Sea with a realistic topography revealing that the breaking process is triggered by the fission mechanism. The associated particles transport is further quantitatively analyzed, revealing a significant transport, both vertically and horizontally. The thesis, finally examined the tidal influences on the basin-scale circulation of the Red Sea. Comparison experiments with and without tides show that, the intrusion of the Gulf of Aden Intermediate Water (GAIW) in summer is strongly influenced by the tides. It is suggested that tides enforce more turbulence and mixing at the strait, which significantly increase the diffusivity of heat and salinity.
322

Signal acquisition, modeling and analysis of the pulmonary circulation system.

January 1993 (has links)
by Ye Jian. / Abstract in English and Chinese. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves [140-147]). / ABSTRACT --- p.i / ACKNOWLEDGEMENTS --- p.v / LIST OF ABBREVIATIONS --- p.vi / TABLE OF CONTENTS / Chapter CHAPTER 1 --- Introduction / Chapter 1.1 --- What is the EBI technique --- p.1-1 / Chapter 1.2 --- Applications of the EBI technique --- p.1-2 / Chapter 1.3 --- The electrical impedance rheopneumography-an overview --- p.1-4 / Chapter 1.4 --- Goal of the work --- p.1-6 / Chapter 1.5 --- Main contributions of the work --- p.1-9 / Chapter 1.6 --- Organization of the thesis --- p.1-9 / Chapter CHAPTER 2 --- Principles of the EBI technique and physiological background of the rheopneumogram / Chapter 2.1 --- Tissue impedance and origins of impedance change --- p.2-1 / Chapter 2.1.1 --- Impedance of living organs --- p.2-1 / Chapter 2.1.2 --- Origins of impedance change --- p.2-2 / Chapter 2.2 --- The data acquisition system (DAS) --- p.2-3 / Chapter 2.2.1 --- Impedance detector --- p.2-3 / Chapter 2.2.2 --- Constant current source and safety consideration --- p.2-4 / Chapter 2.2.3 --- Computer interface --- p.2-5 / Chapter 2.3 --- Electrode systems --- p.2-6 / Chapter 2.3.1 --- Two-/four-electrode systems --- p.2-6 / Chapter 2.3.2 --- Geselowitz lead field theory --- p.2-6 / Chapter 2.3.3 --- Comparisons between the two-/four-electrode systems --- p.2-7 / Chapter 2.4 --- The human cardiovascular system --- p.2-8 / Chapter 2.4.1 --- System operation --- p.2-8 / Chapter 2.4.2 --- Pulmonary hemodynamics --- p.2-9 / Chapter 2.5 --- Physiological background of EIR waveform --- p.2-12 / Chapter 2.6 --- EIR wave morphology and pathological factors --- p.2-13 / Chapter 2.6.1 --- Variations in the a-wave --- p.2-13 / Chapter 2.6.2 --- Variations in the Z-wave --- p.2-14 / Chapter 2.6.3 --- Variations in the C-wave --- p.2-14 / Chapter CHAPTER 3 --- THE COMPOSITION OF IMPEDANCE SIGNAL / Chapter 3.1 --- Introduction --- p.3-1 / Chapter 3.1.1 --- Origins of the TIS --- p.3-1 / Chapter 3.1.2 --- EIR measurement and electrode position --- p.3-2 / Chapter 3.1.3 --- Optimal EIR measurement --- p.3-3 / Chapter 3.2 --- Current path in an inhomogeneous medium --- p.3-4 / Chapter 3.3 --- Numerical model --- p.3-5 / Chapter 3.3.1 --- 2D Model --- p.3-5 / Chapter 3.3.2 --- Tissue resistivity --- p.3-6 / Chapter 3.4 --- Calculation of the potential distribution --- p.3-7 / Chapter 3.5 --- Results --- p.3-9 / Chapter 3.5.1 --- Computer simulations --- p.3-9 / Chapter 3.5.2 --- Experimental results --- p.3-13 / Chapter 3.6 --- Discussions --- p.3-14 / Chapter 3.7 --- Conclusion --- p.3-16 / Chapter 3.8 --- Note on publications --- p.3-17 / Chapter CHAPTER 4 --- ON-LINE RESPIRATORY ARTEFACT REMOVAL VIA ADAPTIVE TECHNIQUE / Chapter 4.1 --- Introduction --- p.4-1 / Chapter 4.2 --- Analysis of the TIS --- p.4-3 / Chapter 4.3 --- Modified adaptive noise canceller --- p.4-7 / Chapter 4.3.1 --- Principle of the ANC method --- p.4-8 / Chapter 4.3.2 --- LMS algorithm --- p.4-8 / Chapter 4.3.3 --- MANC method --- p.4-9 / Chapter 4.3.4 --- Results --- p.4-10 / Chapter 4.4 --- Adaptive moving averager --- p.4-15 / Chapter 4.4.1 --- Modified moving averager --- p.4-15 / Chapter 4.4.2 --- Respiratory artefact elimination with adaptive MMA --- p.4-16 / Chapter 4.4.3 --- Performance of the adaptive MMA filter --- p.4-16 / Chapter 4.4.4 --- Results --- p.4-18 / Chapter 4.5 --- Adaptive FIR filter Design --- p.4-22 / Chapter 4.5.1 --- Introduction --- p.4-22 / Chapter 4.5.2 --- Adaptive FIR filter --- p.4-23 / Chapter 4.5.3 --- Results and discussions --- p.4-24 / Chapter 4.6 --- Simultaneously monitoring respiratory and pulmonary circulation- An application of TIS --- p.4-30 / Chapter 4.7 --- Comparisons of the proposed filter schemes --- p.4-33 / Chapter 4.7.1 --- Performance of the filters --- p.4-33 / Chapter 4.7.2 --- Computational complexity and reduced schemes --- p.4-34 / Chapter 4.8 --- Conclusions --- p.4-37 / Chapter 4.9 --- Notes on publications --- p.4-37 / Chapter CHAPTER 5 --- MODELING ANALYSIS OF THE RHEOPNEUMOGRAM / Chapter 5.1 --- Introduction --- p.5-1 / Chapter 5.2 --- Pulmonary circulation modeling --- p.5-2 / Chapter 5.3 --- Model deduction --- p.5-4 / Chapter 5.3.1 --- Pressure-flow in arteries and veins --- p.5-4 / Chapter 5.3.2 --- The two-chamber model and the EIR model --- p.5-5 / Chapter 5.4 --- Parameter estimation --- p.5-8 / Chapter 5.4.1 --- The fitting function and the parameter equations --- p.5-8 / Chapter 5.4.2 --- Curve fitting --- p.5-10 / Chapter 5.4.3 --- Solution of the parameter equations --- p.5-11 / Chapter 5.5 --- Study of the model parameter sensitivity --- p.5-12 / Chapter 5.6 --- Results --- p.5-13 / Chapter 5.7 --- Conclusion --- p.5-17 / Chapter 5.8 --- Notes on publications --- p.5-17 / Chapter CHAPTER 6 --- ANIMAL EXPERIMENTS AND CLINICAL OBSERVATIONS / Chapter 6.1 --- Introduction --- p.6-1 / Chapter 6.2 --- Animal experiments --- p.6-2 / Chapter 6.2.1 --- Methods --- p.6-2 / Chapter 6.2.2 --- Occlusion of the right pulmonary arterial blood flow --- p.6-3 / Chapter 6.2.3 --- Reflection waves in rheopneumogram --- p.6-4 / Chapter 6.3 --- Clinical observations --- p.6-4 / Chapter 6.3.1 --- Mitral valve stenosis --- p.6-5 / Chapter 6.3.2 --- Obstructive emphysema --- p.6-7 / Chapter 6.4 --- Conclusion remarks --- p.6-8 / Chapter 6.5 --- Notes on publications --- p.6-9 / Chapter CHAPTER 7 --- RECAPITULATION AND TOPICS FOR FUTURE INVESTIGATION / Chapter 7.1 --- Recapitulation --- p.7-1 / Chapter 7.2 --- Conclusions --- p.7-3 / Chapter 7.3 --- Topics for future investigation --- p.7-4 / Chapter 7.4 --- Applications of the EIR technique --- p.7-5 / REFERENCES / APPENDICES / Chapter A. --- A circuit diagram of the four-electrode system --- p.A-l / Chapter B. --- NISA/EMAG (A SOFTWARE PACKAGE OF FEM) --- p.A-2 / Chapter C. --- LMS algorithm --- p.A-3 / Chapter D. --- Curve fitting --- p.A-5 / Chapter E. --- List of publications --- p.A-8
323

Computer-generated circulation diagrams

Kontovourkis, Odysseas January 2009 (has links)
The way in which computers are used is important in the theory, philosophy and practice of architecture. Architects are already using computers to construct complex three dimensional geometric models of their buildings and are beginning to analyse these models using environmental and structural software, a development which raises new questions about the role of architects and engineers. This dissertation puts forward the hypothesis that architects will at times need to be actively involved in computer programming by writing or modifying software. The hypothesis is based on the assumption that the form of a building and its spatial configuration are influenced by the nature of the design process itself. If architects are to have a complete and subtle control over design and to identify their own personal aesthetic language, they must also have control over the design process including the way computer software tools are developed and used. The hypothesis is tested using the example of a ferry terminal, a building type whose function is largely dominated by passenger circulation. Even thought passengers have a very straightforward aim to reach their final destination, the rules governing the way passengers move around the building are complex and a single computer program will not be able to cover all possible aspects of such behaviour. Thus, architects must have the freedom to formulate different rules and study the effects they have on their design. This particularly applies in non-emergency situations when each individual moves inside the building according to different needs and desires. A program was written which runs in real time so that the architect can see the effect of changing the parameters that control the process. The program can be used as evaluation mechanism to study the performance of postulated design or it can be use as creative mechanism where the design may emerge out of the process in the same way that animals create paths in the woods. Either way, the general aim is to optimize the design according to criteria over which the architect, again, must have complete control.
324

La traite des plantes : les intermédiaires de la guérison et le commerce des drogues dans l'Amérique portuguaise, 1750-1808 / Trafficking in plants : intermediaries of healing and the drug trade in Portuguese America, 1750-1808 / O trato das plantas : os intermediários da cura e o comércio de drogas na América portuguesa, 1750-1808

Sanches de Almeida, Danielle 25 September 2017 (has links)
L'expansion à l'étranger et la circulation de nouveaux produits entre le Nouveau et l'Ancien sont l'un des grands enjeux de l'historiographie dédiée au commerce de l'Atlantique et au commerce mondial. Bien que les spécialistes aient travaillé sur cette question en ce qui concerne l'insertion, l'adaptation et la consommation de ces nouveaux genres en Amérique, en Europe, en Asie et en Afrique, il y a eu peu de discussions sur les agents qui ont promu ce mouvement dans le monde entier: les commerçants spécialisés - les pharmaciens - et leurs entreprises commerciales. Cette thèse présente une histoire interconnectée entre ceux qui ont fourni des produits pour le marché médical en Europe et l'Amérique portugaise et la manière dont de nouveaux médicaments ont été introduits par le commerce mondial dans la seconde moitié du 18ème siècle. Son objectif principal est de fournir un aperçu analytique de la compréhension des processus qui ont été mutuellement globaux et locaux, par exemple: comment un médicament amérindien est-il un médicament certifié et garanti par la médecine européenne ou asiatique? Et comment ces produits ont-ils été introduits dans ces circuits et par quels itinéraires du marché? / The overseas expansion and circulation of new products between the New and Old World are one of the great issues for the historiography that is dedicated to the Atlantic trade and to the global commerce. While specialists have been working on this issue with regard to the insertion, adaptation and consumption of these new genres in America, Europe, Asia and Africa, there has been little discussion about the agents who have promoted this movement around the globe: specialized traders - druggists - and their trading companies. This thesis presents an interconnected history between those who provided products for the medical market in Europe and Portuguese America and the ways in which new medicines were introduced by global commerce in the second half of the 18th century. Its main objective is to provide an analytical overview for the understanding of processes that have been mutually global and local, for example: how did an Amerindian medicine become a medicine certified and guaranteed by European or Asian medicine? And how were these products introduced in these circuits and by what market routes?
325

Wind-driven circulation : impact of a surface velocity dependent wind stress

Duhaut, Thomas H. A. January 2006 (has links)
No description available.
326

Mathematical modelling of wind effects on closed lakes / Robert John Arnold

Arnold, Robert John January 1985 (has links)
Bibliography: leaves 231-240 / vi, 240 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, 1986
327

Subseasonal variability in the Southern Hemisphere as simulated by a two-level atmospheric general circulation model

Tomas, Robert A. 17 June 1987 (has links)
The dynamical nature of atmospheric disturbances in the Southern Hemisphere simulated by a two-level general circulation (GCM) model is studied. Time series of the dependent variables and diabatic heating components from 10 Southern Hemisphere winters (JJA) and summers (DJF) simulated by the Oregon State University two-level GCM are used. The time mean fields are presented and discussed. Variance and covariance analyses are performed to determine the geographical distribution, intensities and transport properties of high-frequency (periods between 2.5 and 10 days) and low-frequency (periods between 10 days and a season) transient eddies. These are discussed in terms of dynamical consistency with the time-mean circulation. It is found that the behavior of the high-frequency eddies at mid and high-latitudes is consistent with baroclinic instability theory, i.e., the eddies have properties similar to observed migratory weather disturbances. The low-frequency eddies appear to be quasi-stationary Rossby waves originating at middle latitudes. They seem to disperse energy in a manner consistent with arguments based on simple linear wave dynamics. During wintertime, the time mean flow directs eddies poleward where they grow by baroclinic processes. Also during wintertime, the slow phase velocity, fast group velocity and cyclic domain lead to quasi-resonant behavior on a hemispheric scale. / Graduation date: 1988
328

Analysis of surface wind stress and ocean circulations simulated by general circulation models

Lee, Sheng-wei 01 July 1982 (has links)
Graduation date: 1983
329

The dynamics of mean circulation on the continental shelf /

Shaw, Ping-Tung Peter. January 1900 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1982. / Vita. Includes bibliographical references (p. 221-225).
330

The vertical structure of the wind-driven circulation /

Young, William Roy. January 1981 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1981. / Includes bibliographical references (p. 210-215).

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