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Experimental and numerical analysis of fibre orientation in injection moulded short glass fibre reinforced polyamide 6 notched specimensCaton-Rose, Philip D., Hine, P., Bernasconi, A., Conrado, E. January 2014 (has links)
No / Autodesk Moldflow Simulation Insights has been used to predict the fibre orientation within
notched specimen injection mouldings. Currently available fibre orientation models including
the classis Folgar-Tucker (FT), the modified version of Folgar-Tucker (MFT) and the
Reduced Strain Closure (RSC) [1] have been assessed, alongside the relative effects of their
associated parameters, for their suitability for fibre orientation prediction. Compared to
experimentally determined values the Reduced Strain Closure model was shown to most
closely represent the fibre orientation within the moulded components.
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A composite tracer analysis approach to reservoir characterizationOyerinde, Adedayo Stephen 01 November 2005 (has links)
In the quest for production optimization from established resources, there is a continual interest in secondary and tertiary recovery methods. The success of these enhanced recovery methods, however, rely to a large extent on a sound understanding of fluid dynamics and migration paths in the reservoir. To this end, several approaches to reservoir characterization have been put to test with varying degrees of success.
The unique ability of tracers to provide direct information on preferential fluid flow paths in the reservoir, and the sensitivity of partitioning tracers to fluid saturation distribution has highlighted the prospects of a detailed reservoir characterization through interwell tracer tests.
In a broad sense, analysis of interwell tracer tests fall into two categories, analytical and inverse modeling. While most of the analytical methods are laden with limiting assumptions, the method of moments boasts rigorous formulation and accurate estimates of swept volume and average saturation of bypassed oil. The inverse modeling infers permeability and saturation distribution by matching the tracer response. An extremely effective approach to the inverse modeling methods computes sensitivities based on streamlines.
The accurate modeling of tracer flow requires accounting for complex phenomena such as transverse dispersion. Also, it is sometimes desired to model pertinent tracer components through compositional simulation. This necessitates the inclusion of a physical dispersion tensor and, hence, the well established finite difference formulation.
In this work, we have coupled the finite difference and streamline simulation techniques for the inversion-based reservoir characterization to take advantage of the robustness of the finite difference formulation and computational efficiency of streamline simulation. We have also extended the formalism of the inversion technique for fluid distribution estimation to scenarios with mobile oil saturations and have attempted integrating the analytical and inverse-modeling techniques to facilitate detailed reservoir characterization. We have demonstrated the feasibility of our approach on both synthetic and field cases.
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Atmospheric Sounding Data as Tools for Forecasting Severe Hail and Ozone Accumulation in Arizona during the North American MonsoonJanuary 2019 (has links)
abstract: Monsoon hazards routinely affect the community, economy, and environment of the American Southwest. A common link for hazard development during the North American Monsoon concerns the interplay between temperature, moisture, and wind in the vertical atmosphere controlled by an unstable monsoon circulation. This dissertation investigates vertical atmospheric patterns using in-situ sounding data, specifically, 1) environments favorable for severe hail on the Colorado Plateau, 2) significant parameters distinguishing unhealthy versus healthy ozone days in Phoenix, Arizona, and 3) vertical profile alignments associated with distinct ranges in ozone concentrations observed in Phoenix having defined health impacts.
The first study (published in the Journal of the Arizona-Nevada Academy of Science) determines significant variables on Flagstaff, Arizona 12Z rawinsonde data (1996-2009) found on severe hail days on the Colorado Plateau. Severe hail is related to greater sub-300 hectopascals (hPa) moisture, a warmer atmospheric column, lighter above surface wind speeds, more southerly to southeasterly oriented winds throughout the vertical (except at the 700 hPa pressure level), and higher geopotential heights.
The second study (published in Atmospheric Environment) employs principal component, linear discriminant, and synoptic composite analyses using Phoenix, Arizona rawinsonde data (2006-2016) to identify common monsoon patterns affecting ozone accumulation in the Phoenix metropolitan area. Unhealthy ozone occurs with amplified high-pressure ridging over the Four Corners region, 500 hPa heights often exceeding 5910 meters, surface afternoon temperatures typically over 40°C, lighter wind speeds in the planetary boundary layer under four ms-1, and persistent light easterly flow between 700-500 hPa countering the daytime mountain-valley circulation.
The final study (under revision in Weather and Forecasting) assesses composite atmospheric sounding analysis to forecast Air Quality Index ozone classifications of Good, Moderate, and collectively categories exceeding the U.S. EPA 2015 standard. The analysis, using Phoenix 12Z rawinsonde data (2006-2017), identifies the existence of “pollutant dispersion windows” for ozone accumulation and dispersal in Phoenix.
Ultimately, monsoon hazards result from a complex and evolving vertical atmosphere. This dissertation demonstrates the viability using available in-situ vertical upper-air data to anticipate recurring atmospheric states contributing to specific hazards. These results will improve monsoon hazard prediction in an effort to protect public and infrastructure. / Dissertation/Thesis / Doctoral Dissertation Geography 2019
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Evaluation and Predictability of Observation-based Surface Wind Asymmetric Structure in Tropical CyclonesKlotz, Bradley 30 March 2017 (has links)
Surface wind speeds are an important and revealing component of the structure of tropical cyclones (TCs). To understand the asymmetric structure of surface winds in TCs associated with differences in formation region, environmental wind shear, storm forward motion, and TC strength and intensification, a twelve year database of satellite scatterometer data are utilized to produce composite total wind speed and Fourier-derived, low wavenumber analyses. A quantified asymmetry is determined as a function of TC intensity and reveals the tropical storms are influenced by wind shear at all TC-centric radii but only for areas away from the radius of maximum wind in hurricanes. Additionally, an increase of absolute angular momentum flux has a preference for the downshear-right quadrant, and the low wavenumber maximum develops downwind of this momentum transport. Further evaluation of the asymmetric structure with respect to wind shear’s relation to motion and impacts during TC intensity change are also considered.
A composite rapid intensification event is produced and compared to overlapping satellite rain estimates. Results indicate that the TC becomes more symmetric during intensification and the phase of the maximum asymmetry rotates from a downshear-left direction to upshear-left direction after the intensification slows. The rain or convective maximum is generally located upwind of the surface wind maximum at the early stages of intensification and is coincident with the region of large angular momentum transport, which supports the idea that the surface wind asymmetry is likely a consequence of convective or other processes. Using data from a regional TC model, it is also determined that the scatterometer data are useful for model verification of tropical storms and non-major hurricanes and performs similar to or better than the standard tool at forecast lead times up to 60 hours. Preliminary comparisons of model-derived surface wind asymmetry relative to rain generally confirm the observational results.
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