First, an updated Pacific paleomagnetic skewness pole for chron 32 (72 Ma) is presented. The updated paleomagnetic pole corrects for the spreading-rate dependence of anomalous skewness, a correction which hasn't been applied to Pacific skewness poles before. The presence of anomalous skewness is one of the main factors limiting the accuracy of paleomagnetic poles determined from the skewness data. Thus, successfully correcting for the anomalous skewness, as was done in this study, significantly improves the reliability of the skewness poles. The earlier assertions that the Hawaiian hotspot has shifted southward relative to the spin axis by 13° since ≈72 Ma are also confirmed. Second, updated reconstructions of the Pacific plate relative to the hotspots for the past 68 million years are presented, with the uncertainties in the reconstructions. Plate-circuit reconstructions are used to predict the tracks of some major Indo-Atlantic hotspots (Tristan da Cunha, Reunion and Iceland) from the Pacific-hotspot plate motion and the rates of relative motion between the Pacific and Indo-Atlantic hotspots are estimated. Within the uncertainties, motion between the hotspots is found insignificant for the past 48 million years. For earlier times, a systematic error in the plate circuit used to make the predictions is inferred and which may be due to unmodeled motion between East and West Antarctica. If the observed discrepancy can be shown to correspond to an error in the plate circuit, the southward motion of the Hawaiian hotspot of 13° since ≈72 Ma can likely be attributed to true polar wander. Building on the above-mentioned work, finally, for the first time, a globally self-consistent model of plate motions relative to the global hotspots for the past 48 million years is presented, and the implications of this model to the question of relative hotspot motion discussed. The provided globally self-consistent set of reconstructions can be used as a fixed frame of reference for absolute plate motions, and true polar wander, for the past 48 million years.

Bipolar plates used in a PEM fuel cell must have high electric conductivity, good mechanical and chemical stability, low gas permeability, and low cost. For portable applications, lightweight and low volume should also be considered. Our laboratory has developed a new heterogeneous composite bipolar plate. Which has many advantages, such as low contact resistance, good chemical stability, low cost, lightweight and high performance. Since automation is the key to low cost, this research is to develop the automatic fabrication process of the new plate. The process involves mainly the making of carbon fiber bunches by sticking the central portion of the carbon fiber together with glue but leaving both ends free. Secondly, use injection molding to form the plastic main body with all the carbon fiber bunches. In order to shorten the developing time, we divide the process into four parts: (1) the unfolding of carbon fiber (2) the automation of gluing (3) harden and cutting to sizes (4) Injection molding of bipolar plates. This thesis has completed the study of the first three parts of the manufacturing processes. We have compared the contact resistances between our product and the previously handmade ones and found that the results are satisfactory.

The operation of a complete license plate recognition system includes three parts: license plate localization, character segmentation, and character identification. Among these three parts, license plate localization is relatively more difficult and complicated. Until now, differentiating background and real license plate images in real and random traffic conditions remains to be a very difficult task. Via a VQ coding technique, this study introduces a method resolve this problem. As a preprocessing step, this method first converts an image to be classified into binary form by using statistics generated from a license plate image database. The next step of the proposed approach is to use a VQ method to represent the image by a series of codewords. By computing the probability of these codewords used by the license plate and background images, these codewords are renumbered. By using neural networks to classify such images, our experimental results show that the proposed approach can differentiate background and real license plate images with a very high successful rate.

In this research a modified commercial boiler,which burns diesel oil,is used to study the combustion characterisics and the pollution of the exhausting products under various operating conditions.The controlling ranges of the various experimental parameters include equivalence ratio from 0.8to1.1,swirl number 0 and 0.6, the flue rate of the recirculated flue gas from 0% to 12%, and jet spray angle 80. The effect of the above various operating conditions on the combustion characteristics and the formation of pollutants are studied in this research. A photographic technology is used to study the combustion behaviors of the flame under various operating condition. Flame structures display that when the flow rate of the recirculated flue gas increase, the flame color in primary combustion zone will change gradually from high temperature white-yellow flame to low temperature orange-red flame. At plate angle 0 and 45, the primary combustion zone with plate angle 45 occurs near burner so that we cannot see too much white-yellow zone from quartz window. The flame outside of the primary combustion region exhibits the red color which is due to the radition of CO2 and water vapor. In addition, when the strength of the swirl increases the contour of the flame will change gradually from smooth shape to strongly distortion.

The apparent polar wander path (APWP) for the Pacific plate during the Late Cretaceous and Early Cenozoic has been constrained primarily by seamount magnetic anomaly inversions and seafloor magnetic anomaly skewness. The reliability of these data types is uncertain and data are too sparse to provide a consistent or detailed APWP. In an effort to refine the Pacific APWP, we collected a larger, more diverse data set that allowed for the calculation of new mean paleomagnetic poles for the latest Cretaceous and Paleogene. We combined four types of data including sediment core paleocolatitudes, basalt core paleocolatitudes, seamount magnetic anomaly inversion declinations, and effective inclinations from magnetic anomaly skewness calculations. This diverse data set yields paleomagnetic poles that are less affected by bias from any particular data type. We found reasonably good agreement between data types and calculated five mean paleomagnetic poles representing the Oligocene (30 Ma), Late (39 Ma) and Early (49 Ma) Eocene, and Paleocene (61 Ma) epochs and the Maastrichtian (68 Ma) stage. Though a significant percentage of the data are from azimuthallyunoriented cores, which do not provide constraint on paleodeclination, a wide distribution of sites and the use of declination data from seamount anomaly inversions gave relatively good control on pole paleolongitude. The large numbers of data in our calculations allow for reasonably compact uncertainty bounds and the overall agreement among most data implies insignificant systematic errors in the data set. The greatest disagreement among data occurs due to a divergence between poles from anomaly skewness and other data types prior to 55 Ma. As a whole, the new APWP implies northward Pacific plate drift. However, this motion is punctuated with a stillstand from the Late Cretaceous (~80 Ma) until the middle Eocene, (~49 Ma). This stillstand suggests a lack of northward Pacific plate motion during this time, counter to most accepted models. This APWP is consistent with paleomagnetic results from the Emperor Chain that indicate the Hawaiian hotspot moved south during formation of the Emperor Chain, but it implies an amount of motion slightly greater than that previously proposed for hotspot drift.

Thesis (M. Sc.) -- University of Canterbury, 2009. / Also available via the World Wide Web.

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Not available / text

Convergent continental margins are regions of intense deformation caused by the interaction of oceanic plates with continents. The spatial extent of deformation is broadly commensurate with the specific time scale of the causative phenomenon. For example, subduction-related short-term deformation is limited to <200 km from the margin, whereas long-term plate convergence cause deformation over ∼1000 km landward. Deformation is thus manifested in multiple ways, with attributes depending on the scale of measurement. In this thesis we investigate the use of two geophysical approaches in the study of deformation: 1) The analysis of potential-field anomalies to derive estimates of the elastic thickness (Te) of the lithosphere, and 2) The structural study of past and present subduction systems using seismic observations and modelling. Both approaches involve the development of appropriate methodologies for data analysis and modelling, and their application to the western Canadian landmass. Our findings are summarized as follows: 1) We develop a wavelet-based technique to map variations in Te and its anisotropy; 2) We show how a step-wise transition in Te and its anisotropy from the Cordillera to the Craton is a major factor influencing lithospheric deformation; 3) We implement a waveform modelling tool that includes the effects of structural heterogeneity and anisotropy for teleseismic applications, and use it to model the signature of a fossil subduction zone in a Paleoproterozoic terrane; 4) We use teleseismic recordings to map slab edge morphology in northern Cascadia and show how slab window tectonism and slab stretching led to the creation of the oceanic Explorer plate; 5) We use seismic signals from the subducting oceanic crust to calculate elevated Poisson’s ratio and infer high pore-fluid pressures and a low-permeability plate boundary within the forearc region of northern Cascadia.

<p> The history of late Miocene (Proto-Gulf) deformation on the Sonoran margin of the Gulf of California is key to understanding how Baja California was captured by the Pacific plate and how strain was partitioned during the Proto-Gulf period (12.5-6 Ma). The Sierra el Aguaje and Sierra Tinajas del Carmen are located in southwestern coastal Sonora, Mexico, and represent the eastern rifted margin of the central Gulf of California. The ranges are composed of volcanic units and their corresponding volcaniclastic units which are the result of persistent magmatic activity between 20 and 8.8 Ma, including three packages of basalt and andesite that make excellent paleomagnetic recorders. Based on cross cutting relations and geochronologic data for pre-, syn-, and post-tectonic volcanic units, most of the faulting and tilting in the Sierra El Aguaje is bracketed between 11.9 and 9.0 Ma, thus falling entirely within Proto-Gulf time. </p><p> A paleomagnetic investigation into possible vertical axis rotations in the Sierra el Aguaje has uncovered evidence of clockwise rotations between ~13&ordm; and ~105&ordm; with possible translations. These results are consistent with existing field relations, which suggest the presence of large (>45&deg;) vertical axis rotations in this region. This evidence includes: a) abrupt changes in the strike of tilted strata in different parts of the range, including large domains characterized by E-W strikes b) ubiquitous NE-SW striking faults with left lateral-normal oblique slip, that terminate against major NW-trending right lateral faults, and c) obliquity between the general strike of tilted strata and the strike of faults. These rotations occurred after 12 Ma and largely prior to 9 Ma, thus falling into the Proto-Gulf period. Such large-scale rotations lend credence to the theory that the area inboard of Baja California was experiencing transtension during the Proto-Gulf period, rather than the pure extension that would be the result of strain partitioning between Sonora and the Tosco-Abreojos fault offshore Baja California.</p>