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Low noise techniques applied to a piezoceramic receiver for gas coupled ultrasonic flaw detectionFarlow, Roger January 1998 (has links)
Piezoelectric plate transducers are commonly used for the generation and detection of ultrasonic signals and have applications in, for example, non-destructive testing and medical imaging. A rigorous theoretical investigation of thermal noise in plate transducers has been undertaken with the aim of establishing the absolute limits of receiver sensitivity in terms of both Minimum Detectable Power (MDP) and Minimum Detectable Force (MDF). The central feature of the work has been the development of two independent theories which provide identical results. One theory is based on an electrical approach which makes use of an extensively modified version of Hayward's linear systems model of the piezoelectric plate transducer, along with the well known work of Johnson and Nyquist. The other theory is based on a mechanical approach which makes use of the less well known work of Callen and Welton. Both theories indicate that only two parameters are required in order to determine the MDP and MDF of an open circuit transducer. These parameters are the transducer's characteristic acoustic impedance and its mechanical quality factor. Significantly, the thermally limited sensitivity of an open circuit receiving transducer has been shown not to be related to its electromechanical coupling efficiency or any of its electrical properties. By applying the new theories it has been possible to design an ultra low noise ultrasonic receiver with wide ranging applications. Among other things, this receiver has been used to demonstrate the viability of a robust and truly practical air-coupled Lamb wave scanner suitable for detecting defects in thin plates which can be made from almost any type of material. The complete system has sufficient sensitivity to allow rapid scanning without the requirement for transducer matching layers or electronic signal averaging.
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Late Roman precious metal deposits, c. AD 200-700 : changes over time and spaceHobbs, Richard January 1997 (has links)
This thesis draws together more than 1,800 deposits of late Roman precious metals, namely coins, plate, jewellery, and bullion items, over a 500 year period (c. AD200- 700). Deposits from both West and East of the Empire, and beyond the frontiers, are included. Comparisons between these finds are made by focusing on three main aspects: spatial distribution, size, and date range of items within finds, by dividing the material into 22 deposition phases. A methodology has been developed allowing the size of each find to be compared, regardless of its internal structure and precious metal content (i.e. gold or silver), by assigning each find an Equivalent Gold Weight. Hence it is made possible to compare, for instance, a deposit of base metal silver coinage with a deposit of church silver plate, at least in terms of size, which previously has not been attempted. Past approaches to the interpretation and presentation of these finds are examined, with the aim of this research being to move away from traditional foci of study, namely the internal structure of hoards, epigraphy and iconography, and towards producing a background picture on a far broader level, chronologically and spatially. The deposition phases are surveyed in isolation, and then compared: changes in the focus of deposition activity are thus highlighted. The value of the approach adopted by this study with regard to our understanding of late Roman precious metal deposition is tested by comparing the recent late Roman find from Patching, West Sussex, with the database. Previous theoretical interpretations of hoard deposition are examined in the light of this body of evidence, for example, the question of the relationship between hoarding and social unrest, and the evidence for social traditions of deposition and ritual use of material in different areas within the study region. Finally, other areas of potentially productive future research, in addition to the themes explored in the previous chapters, are discussed.
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The hydraulic connectivity, perennial warming and relationship to seismicity of the Davis-Schrimpf Seep Field, Salton Trough, California from new and recent temperature time-seriesRao, Amar P. 16 February 2017 (has links)
<p> The Davis-Schrimpf Seep Field is a cluster of about 50 transtension-related geothermal seeps in the Imperial Valley, southeastern California. Five temperature time-series were collected from four features and compared to one another, against prior time-series, and to local seismicity. Loggers placed in separate vents within one seep returned moderate anti-correlation. Vents may selectively clog and unclog. Clogging frequencies explaining the observed level of negative correlation were given. Loggers placed in the same vent produced 87-92% positive correlation. It is therefore likely that the vast majority of temperature data measured with loggers possesses meaningful accuracy. Loggers placed in separate seeps exhibited correlation close to or greater than the statistically significant 60% threshold. I propose two lineaments provide a hydraulic connection between these seeps. Two M<sub>w</sub>>3.0 earthquake swarms, including one M<sub>w</sub>>4.0 event, within 24 kilometers showed possible linkage with >5 degree Celsius temperature perturbations. Seepage warmed 14.5-36.8 degrees Celsius over 5-7 years.</p>
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Phenotypic characterization of cartilage cells during endochondral ossification (an avian growth plate model).January 1990 (has links)
by Lee Kwong Man, Simon. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1990. / Bibliography: leaves 88-94. / ABSTRACT --- p.I / ACKNOWLEDGEMENTS --- p.IV / TABLE OF CONTENTS --- p.V / Chapter CHAPTER ONE - --- INTRODUCTION --- p.1 / Chapter CHAPTER TWO - --- STRUCTURE OF CARTILAGE / Chapter 2.1 --- Characteristics of Cartilage --- p.4 / Chapter 2.2 --- Types of Cartilage --- p.4 / Chapter 2.3 --- Matrix --- p.5 / Chapter 2.3.1 --- Collagen --- p.5 / Chapter 2.3.2 --- Proteoglycan --- p.7 / Chapter 2.4 --- Diffusion of Solultes in Cartilage --- p.9 / Chapter 2.5 --- Chondroytes --- p.10 / Chapter CHAPTER THREE - --- PHYSIOLOGICAL CHANGES WITHIN CARTILAGE / Chapter 3.1 --- Endochondral Ossification --- p.12 / Chapter 3.2 --- Hormone Responses on Cartilage --- p.16 / Chapter 3.3 --- Degradative enzymatic system --- p.17 / Chapter 3.3.1 --- Evidence for the Role of Enzymes in osteoarthritis --- p.18 / Chapter 3.3.2 --- Neutral Protease Acivity --- p.20 / Chapter 3.3.3 --- Neutal proteases in osteoarthritis --- p.21 / Chapter 3.3.4 --- Collagenase activity in articular cartilage --- p.22 / Chapter CHAPTER FOUR - --- METHODOLOGIES / Chapter 4.1 --- Isolation of Chick Growth Plate and Articular Chondrocytes --- p.24 / Chapter 4.2 --- Countercurrent Centrifugal Elutriation --- p.25 / Chapter 4.3 --- Size Determination of Chondrocytes --- p.26 / Chapter 4.4 --- Chondrocyte Cell Culture --- p.28 / Chapter 4.5 --- Flow Cytometry Cell Cycle Analysis of Elutriated Chondrocytes --- p.28 / Chapter 4.6 --- Thymidine Incorporation Assay on Elutriated Chondrocytes --- p.29 / Chapter 4.7 --- Sulfur Incorporation Assay on Elutriated Chondrocytes --- p.30 / Chapter 4.8 --- Hyalurondiase Assay on Elutriated Chondrocytes --- p.31 / Chapter 4.9 --- Alkaline Phosphatase Assay on Elutriated Chondrocytes --- p.32 / Chapter 4.10 --- Acid Phosphatase Assay --- p.33 / Chapter 4.10.1 --- Total Acid Phosphatase Assay on Elutriated Chondrocytes --- p.33 / Chapter 4.10.2 --- Optimal pH Determination of Phosphatase in Isolated Chondrocytes --- p.33 / Chapter 4.10.3 --- Enzyme Kinetics of Acid Phosphatase of Isolated Growth Plate and Articular Chondrocytes --- p.34 / Chapter 4.10.4 --- Tartrate Inhibition Effect on Acid Phosphatase of Growth Plate and Articular Chondrocytes --- p.35 / Chapter 4.10.5 --- Distribution of Acid Phosphatase Isoenzymes Among Chondrocytes of Different Size --- p.35 / Chapter 4.11 --- Hormonal Effects on Acid and Alkaline Phosphatase Activities in Growth Plate and Articular Chondrocytes --- p.36 / Chapter CHAPTER FIVE - --- RESULTS / Chapter 5.1 --- Morphology of the Isolated Chick Chondrocytes --- p.39 / Chapter 5.2 --- Countercurrent Centrifugal Elutriation VI --- p.39 / Chapter 5.3 --- Thymidine Incorporation Assay on Elutriated Chondrocytes --- p.44 / Chapter 5.4 --- Flow Cytometer Cell Cycle Analysis of Elutriated Chondrocytes --- p.44 / Chapter 5.5 --- Sulfate Incorporation Assay on Elutriated Chondrocytes --- p.48 / Chapter 5.6 --- Hyaluronidase Assay on Elutriated Chondrocytes on --- p.48 / Chapter 5.7 --- Alkaline Phosphatase Assay on Elutriaed Chondrocytes --- p.48 / Chapter 5.8 --- Acid Phosphatase Assay --- p.52 / Chapter 5.8.1 --- pH Curve of Phosphatase in Isolated Chondrocytes --- p.52 / Chapter 5.8.2 --- Enzyme Kinetics of Acid Phosphatase oflsolated Growth Plate and Articular Chondrocytes --- p.52 / Chapter 5.8.3 --- Tartrate Inhibition Effect on Acid Phosphatae of Growth Plate and Articular Chondrocytes --- p.55 / Chapter 5.8.4 --- Distribution of Acid Phosphatase Isoenzymes Among Chondrocytes in Different Size --- p.57 / Chapter 5.9 --- Hormonal Effects on Acid and Alkaline Phosphatase Activities in Growth Plate and Articular Chondrocytes --- p.59 / Chapter CHAPTER SIX - --- DISCUSSION / Chapter 6.1 --- Identification of Chondrocyte Subpopulations --- p.63 / Chapter 6.2 --- Characterization of Chondrocyte Subpopulations --- p.72 / Chapter 6.3 --- Characterization of Acid Phosphatase in Chick Chondrocytes --- p.74 / LIST OF FIGURES --- p.84 / LIST OF TABLES --- p.87 / REFERENCES --- p.88 / Chapter APPENDIX I --- Principle of Countercurrent Centrifugal Elutriation --- p.95 / Chapter APPENDIX II --- Principle of Flow Cytometry --- p.98 / Chapter APPENDIX III --- Reagents for Experiments --- p.103
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In vitro and in situ porcine models for the studies on phenotypic characterization of cartilage cells during endochondral ossification.January 1996 (has links)
by Lee Kwong Man, Simon. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 239-277). / ABSTRACT --- p.i / ACKNOWLEDGMENT --- p.vi / PUBLICATIONS --- p.vii / ABBREVIATIONS --- p.viii / TABLE OF CONTENT --- p.xi / Chapter CHAPTER ONE --- General Introduction --- p.1 / Chapter CHAPTER TWO --- Identification and Biochemical Characterization of Various Differentiative Growth Plate Chondrocytes by Countercurrent Centrifugal Elutriation --- p.8 / Chapter CHAPTER THREE --- Differential Expression of Glycoconjugates during Endochondral Ossification in Porcine Growth Plate --- p.50 / Chapter CHAPTER FOUR --- Intra- & Extra-Cellular Free Calcium Activities of Porcine Growth Plate Chondrocytes at Various Stages of Maturation --- p.90 / Chapter CHAPTER FIVE --- A New In Situ Model for Electrophysiological Characterization of Ionic Channels in Growth Plate Chondrocytes --- p.144 / Chapter CHAPTER SIX --- Effects of Quinolones on Growth Plate Chondrocytes --- p.201 / Chapter CHAPTER SEVEN --- Summary and Conclusion --- p.226 / BIBLIOGRAPHY --- p.239
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LRFD design of plate girders for buildingsHan, Hyoseop January 2010 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries / Department: Civil Engineering.
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The mechanics of the Salt Range-Potwar Plateau, Pakistan : qualitative and quantitative aspects of a fold-and-thrust belt underlain by evaporitesJuame, Steven C. 02 December 1986 (has links)
The collision of the Indian subcontinent with Asia beginning 40 million years ago
produced the Himalayan orogenic belt, the largest continental collision belt active today. The foreland fold-and-thrust belt in northern Pakistan consists of the Salt Range-Potwar Plateau area. In this region the distance from the Main Boundary Thrust(MBT) to the front of the fold-and-thrust belt is very wide (100-150 km) because a thick evaporite sequence forms the zone of décollement.
Recent studies have combined seismic reflection profiles, petroleum exploration
wells, Bouguer gravity anomalies, and surface geology to construct cross sections in the eastern, central, and western Salt Range-Potwar Plateau areas. In this study the sections are compared with a previous model that considers the mechanics of a fold-and-thrust belt to be analogous to that of a wedge of snow or soil pushed in front of a bulldozer (Davis et al., 1983; Dahlen et al., 1984; Dahlen, 1984), and a later model (Davis and Engelder, 1985) which suggests that fold-and-thrust belts underlain by salt will have: a) narrow (< 1°) cross-sectional tapers, b) larger widths than areas not underlain by salt, c) symmetrical structures, and d) changes in deformational style at the edge of the salt basin.
The section across the eastern Potwar Plateau most closely resembles this latter
model, having: a) a taper of 0.8° ± 0.1°, b) a width of 100-150 km, c) thrust faults that verge both to the north and south, and d) structures rotated 30° counterclockwise with respect to the Salt Range. From the observed taper and pore fluid pressures of the eastern Potwar Plateau, estimates of the values for the yield strength of the evaporites (τ₀) and the coefficent of internal friction (μ) are calculated as τ₀ = 1.33-1.50 MPa and μ = 0.95-1.04, which are then applied to the other cross sections.
In the central and western sections a basement uplift, the Sargodha High, interferes with the front of the fold-and-thrust belt. This feature causes the ramping of the Salt Range Thrust and produces a relatively steep basement slope (2°-4°) beneath the
Potwar Plateau. This dip, together with the weak evaporite layer, allows the thrust wedge of the southern Potwar Plateau to be pushed over the décollement without undergoing internal deformation. In detail, the Salt Range ramping is caused by a large
normal fault in the basement in the central section and the basement upwarp of the Sargodha High in the western section.
The northern Potwar Plateau is strongly folded and faulted, yet the topographic slope remains flat. Although the deformation suggests that salt is not present there, the observed taper in the northern Potwar Plateau is best fitted by the model with salt at the
décollement. Combining this with published paleomagnetic and geologic constraints, a model for the evolution of the northern Potwar Plateau suggests that the area deformed
as a steeply tapered (3.5°-5.5°) thrust wedge until approximately 2 million years ago, when the décollement encountered the Salt Range formation. Between 2 m.y.a. and the
present, the northern Potwar Plateau has been pushed along the salt décollement without deformation, and erosion has reduced its original steep topographic slope to a nearly level surface.
The success of the mechanical model in predicting the observed features in the Salt Range-Potwar Plateau suggests that salt may lie beneath other fold-and-thrust belts in Pakistan. Two areas, the Sulaiman Lobe and the Karachi Arc, are possible candidates.
Although published subsurface information is lacking in these areas, surface observations show that they both: a) extend far across the foreland, b) exhibit low
topographic slopes, c) display symmetrical structures, and d) show a change in structural orientation along what is believed to be the edge of the salt basin. / Graduation date: 1987
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A Comparison of Residual Analysis Methods for Space-time Point Processes with Applications to Earthquake Forecast Models.Clements, Robert Alan. Unknown Date (has links)
Modern, powerful techniques for the residual analysis of spatial-temporal point process models are reviewed and their power under various null and alternative hypotheses is compared. Residual methods can be divided into two schemes: transformation-based and pixel-based methods. Rescaling, thinning and superposition are useful transformation-based methods for the residual analysis of spatial-temporal point processes. These techniques involve transforming the original point process into a new process that should be a homogeneous Poisson process if and only if the fitted model is correct, so that one may inspect the residual process for homogeneity using standard tests for homogeneity as a means of assessing the goodness-of-fit of the model. Unfortunately, tests of homogeneity performed on residuals based on these three residual methods tend to have low power when the modeled conditional intensity of the original process is volatile. For such purposes, we propose the method of super-thinning, which combines thinned residuals and superposition. This technique involves the use of a tuning parameter, k, which controls how much thinning and superposition are performed to homogenize the process. The method is applied to the assessment of a parametric space-time point process model for the origin times and epicentral locations of recent major California earthquakes. / These residual methods are then applied to California earthquake forecast models used in the Collaboratory for the Study of Earthquake Predictability (CSEP). Assessments of these earthquake forecasting models have previously been performed using simple, low-power means such as the L-test and N-test. We instead propose using the transformation residual methods for model assessment, and the pixel-based methods, such as Pearson and deviance residuals, to compare competing models. The different residual analysis techniques are demonstrated using the CSEP models and are used to highlight certain deficiencies in the models. / Both pixel-based and transformation methods are evaluated through a simulation study by applying each method to a group of Hawkes processes that contain different degrees of clustering and inhibition. Pixel-based methods, such as raw, Pearson, inverse, deviance, and tessellation residuals appear to be generally weaker than transformed residuals at detecting insufficient or excessive local clustering in the model. The transformation method of super-thinning is shown to have relatively high power when the value of the tuning parameter, k, is carefully chosen. / Finally, we introduce the R package stppResid, which implements both transformation and pixel-based residual analysis for space-time point process models. We illustrate the use of each of these residual tools by applying them to a well known space-time point process model fitted to a red banana data set.
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Tectonic modeling of Northern Luzon, Philippines and regional implicationsQueano, Karlo Lagera. January 2006 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.
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Crustal and upper mantle investigations of the Caribbean-South American plate boundaryJanuary 2010 (has links)
The evolution of the Caribbean --- South America plate boundary has been a matter of vigorous debate for decades and many questions remain unresolved. In this work, and in the framework of the BOLIVAR project, we shed light on some aspects of the present state and the tectonic history of the margin by using different types of geophysical data sets and techniques. An analysis of controlled-source traveltime data collected along a boundary-normal profile at ∼65°W was used to build a 2D P-wave velocity model. The model shows that the Caribbean Large Igenous Province is present offshore eastern Venezuela and confirms the uniformity of the velocity structure along the Leeward Antilles volcanic belt. In contrast with neighboring profiles, at this longitude we see no change in velocity structure or crustal thickness across the San Sebastian - El Pilar fault system. A 2D gravity modeling methodology that uses seismically derived initial density models was developed as part of this research. The application of this new method to four of the BOLIVAR boundary-normal profiles suggests that the uppermost mantle is denser under the South American continental crust and the island arc terranes than under the Caribbean oceanic crust. Crustal rocks of the island arc and extended island arc terranes of the Leeward Antilles have a relatively low density, given their P-wave velocity. This may be caused by low iron content, relative to average magmatic arc rocks. Finally, an analysis of teleseismic traveltimes with frequency-dependent kernels produced a 3D P-wave velocity perturbation model. The model shows the structure of the mantle lithosphere under the study area and clearly images the subduction of the Atlantic slab and associated partial removal of the lower lithosphere under northern South America. We also image the subduction of a section of the Caribbean plate under South America with an east-southeast direction. Both the Atlantic and Caribbean subducting slabs penetrate the mantle transition zone, affecting the topography of the 410-km and 660-km discontinuities.
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