There are many options available when selecting a computational model for two-phase flows. It is important to understand all the features of the model selected, including when the model is appropriate and how using it may affect your results. This work examines how volume displacement effects in two-phase Eulerian-Lagrangian models manifest themselves. Some test cases are examined to determine what input these effects have on the flow, and if we can predict when they will become important. Bubble injection into a traveling vortex ring is studied in-depth, as it provides significant insight into the physics of these volume displacement effects. When a few bubbles are entrained into a traveling vortex ring, it has been shown that even at extremely low volume loadings, their presence can significantly affect the structure of the vortex core (Sridhar & Katz 1999). A typical Eulerian-Lagrangian point-particle model with two-way coupling for this dilute system, wherein the bubbles are assumed subgrid and momentum point-sources are used to model their effect on the flow, is shown to be unable to accurately capture the experimental trends of bubble settling location, bubble escape, and vortex distortion for a range of bubble parameters and vortex strengths. Accounting for fluid volume displacement due to bubble motion, using a model termed as volumetric coupling, experimental trends on vortex distortion and bubble settling location are well captured. The fluid displacement effects are studied by introducing the notion of a volume displacement force, the net force on the fluid due to volumetric coupling, which is found to be dominant even at the low volume loadings investigated here. A method of quantifying of these forces is derived and used to study the effects for a wide range of particle to fluid density ratios in Taylor-Green vortices. A simple modification to the standard point-particle Lagrangian approach is developed, wherein the interphase reaction source terms are consistently altered to account for the fluid displacement effects and reactions due to bubble accelerations. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from Sept. 24, 2012 - Sept. 24, 2013

This thesis develops a strategy for polymerized volume data set construction. Given a volume data set defined over a regular three-dimensional grid, a polymerized volume data set (PVDS) can be defined as follows: edges between adjacent vertices of the grid are labeled 1 (active) or 0 (inactive) to indicate the likelihood that an edge is contained in (or spans the boundary of) a common underlying object, adding information not in the original volume data set. This edge labeling “polymerizes” adjacent voxels (those sharing a common active edge) into connected components, facilitating segmentation of embedded objects in the volume data set. Polymerization of the volume data set also aids real-time data compression, geometric modeling of the embedded objects, and their visualization. To construct a polymerized volume data set, an adjacency class within the grid system is selected. Edges belonging to this adjacency class are labeled as interior, exterior, or boundary edges using discriminant functions whose functional forms are derived for three local adjacency classes. The discriminant function parameter values are determined by supervised learning. Training sets are derived from an initial segmentation on a homogeneous sample of the volume data set, using an existing segmentation method. The strategy of constructing polymerized volume data sets is initially tested on synthetic data sets which resemble neuronal volume data obtained by three-dimensional microscopy. The strategy is then illustrated on volume data sets of mouse brain microstructure at a neuronal level of detail. Visualization and validation of the resulting PVDS is shown in both cases. Finally the procedures of polymerized volume data set construction are generalized to apply to any Bravais lattice over the regular 3D orthogonal grid. Further development of this latter topic is left to future work.

Rendering in computer graphics is the process of converting a three dimensional scene description into a two dimensional image. In this work we focus on high quality rendering, which has numerous applications in entertainment and visualization. Many films today are created either entirely or in concert with computationally generated imagery and serve as a vivid example of the benefits of high quality rendering. This dissertation consists of two parts, each presenting novel work in the field of high quality, high performance rendering. The first part proposes the use of volumetric occluders, or a collection of axis-aligned boxes placed within a polygonal model, to accelerate the rendering of shadows cast by the model while producing images identical to the unaccelerated baseline. We show that our approach performs well on single object scenes and extend our approach for use with scenes from a professional open source movie. Although the technique has not yet proven itself on these multi-object scenes, we identify the scene characteristics which are hampering the approach and show that in some cases it is still possible to achieve an improvement in performance. The second part of the dissertation presents a new way to determine micropolygon tessellation rate within a Reyes style renderer. Our new scheme, called final approach tessellation, evaluates the tessellation rate close to a Reyes surface rather than upon entry into its bounding box. Our determination of the tessellation rate is more aggressive than previous approaches, producing a more compact tessellation which in turn is faster to compute and requires less memory. Our evaluation shows that although final approach tessellation is promising in theory, it ultimately fails to improve performance on actual test scenes. / text

Pasyviųjų priemaišų jūrinėje aplinkoje įvertinimas ypač svarbus gamtosauginiu aspektu. Ypatingas dėmesys skiriamas Baltijos jūros ekologinei būklei, kurią lemia jūros dubens ypatybės, silpnas ryšys su Pasauliniu vandenynu, klimatinės ir hidrometeorologinės sąlygos. Pastaraisiais dešimtmečiais jūros baseine didėja antropogeninės kilmės teršalų kiekis. Branduolinės fizikos ir technikos plėtra neišvengiamai sukelia technogeninės kilmės radionuklidų patekimą į jūrinę aplinką. Daug dėmesio skiriama 137Cs radionuklidui, nes iki šiol jūros vandens tyrimai rodo aukštas šio radionuklido tūrinio aktyvumo reikšmes. Be to, 137Cs radionuklidas geras indikatorius, tiriant kitų pasyviųjų priemaišų migraciją Baltijos jūros vandenyje. Daug mokslininkų nagrinėja problemas, susijusias su technogeninės kilmės radionuklidų kiekiais, jų sklaida ir poveikiu jūrinei aplinkai. Tačiau darbų, kuriuose būtų nagrinėjama radionuklidų tūrinių aktyvumų pokyčių bei pernašos Baltijos jūros priekrantės vandenyje problema, praktiškai nėra. Atsižvelgiant į tai, šiame darbe nustatytas 137Cs radionuklido tūrinis aktyvumas Baltijos jūros Lietuvos priekrantės paviršiniame vandenyje bei įvertinti hidrometeorologiniai parametrai. 137Cs radionuklido tūrinis aktyvumas Baltijos jūros vandenyje nėra pastovus, todėl aktualu parinkti tinkamus nustatymo metodus ir vertinti jo pokyčių tendencijas. Įvertinus radiocezio tūrinio aktyvumo pokyčius priekrantės vandenyje, galima modeliuoti ir prognozuoti taršos šaltinio atsiradimo... [toliau žr. visą tekstą] / The evaluation of the passive admixture transfer in the marine environment is very significant from the point of view of environmental protection. A particular attention is devoted to the Baltic Sea ecological state, which is strongly influenced by the peculiarities of the sea bottom, weak connection with the World Ocean, climatic and hydrometeorological conditions. During the recent decades, the tendency of increment of the amount of anthropogenic pollutants is observed. The development of nuclear energetics and technology inevitably causes the spread of radionuclides of technical origin in the marine environment. The major attention is paid to the investigation of the radionuclide 137Cs distribution, since the investigations show the high values of the volumetric activity of this radionuclide to be present in the sea water thus far. Besides that, 137Cs radionuclide can be used as a tracer in investigations of the migration of other passive admixtures in the Baltic Sea water. Quite a number of scientists research the problems related with the amounts of the radionuclide of technical origin, their spread and impact on the marine environment. However, the works considering a problem of the variations of volumetric activity of radionuclides and their transfer in the coastal waters of the Baltic Sea practically are not encountered. Considering that, the volumetric activity of radionuclide 137Cs in the coastal surface waters of the Lithuanian territorial zone of the Baltic Sea... [to full text]

The evaluation of the passive admixture transfer in the marine environment is very significant from the point of view of environmental protection. A particular attention is devoted to the Baltic Sea ecological state, which is strongly influenced by the peculiarities of the sea bottom, weak connection with the World Ocean, climatic and hydrometeorological conditions. During the recent decades, the tendency of increment of the amount of anthropogenic pollutants is observed. The development of nuclear energetics and technology inevitably causes the spread of radionuclides of technical origin in the marine environment. The major attention is paid to the investigation of the radionuclide 137Cs distribution, since the investigations show the high values of the volumetric activity of this radionuclide to be present in the sea water thus far. Besides that, 137Cs radionuclide can be used as a tracer in investigations of the migration of other passive admixtures in the Baltic Sea water. Quite a number of scientists research the problems related with the amounts of the radionuclide of technical origin, their spread and impact on the marine environment. However, the works considering a problem of the variations of volumetric activity of radionuclides and their transfer in the coastal waters of the Baltic Sea practically are not encountered. Considering that, the volumetric activity of radionuclide 137Cs in the coastal surface waters of the Lithuanian territorial zone of the Baltic Sea... [to full text] / Pasyviųjų priemaišų jūrinėje aplinkoje įvertinimas ypač svarbus gamtosauginiu aspektu. Ypatingas dėmesys skiriamas Baltijos jūros ekologinei būklei, kurią lemia jūros dubens ypatybės, silpnas ryšys su Pasauliniu vandenynu, klimatinės ir hidrometeorologinės sąlygos. Pastaraisiais dešimtmečiais jūros baseine didėja antropogeninės kilmės teršalų kiekis. Branduolinės fizikos ir technikos plėtra neišvengiamai sukelia technogeninės kilmės radionuklidų patekimą į jūrinę aplinką. Daug dėmesio skiriama 137Cs radionuklidui, nes iki šiol jūros vandens tyrimai rodo aukštas šio radionuklido tūrinio aktyvumo reikšmes. Be to, 137Cs radionuklidas geras indikatorius, tiriant kitų pasyviųjų priemaišų migraciją Baltijos jūros vandenyje. Daug mokslininkų nagrinėja problemas, susijusias su technogeninės kilmės radionuklidų kiekiais, jų sklaida ir poveikiu jūrinei aplinkai. Tačiau darbų, kuriuose būtų nagrinėjama radionuklidų tūrinių aktyvumų pokyčių bei pernašos Baltijos jūros priekrantės vandenyje problema, praktiškai nėra. Atsižvelgiant į tai, šiame darbe nustatytas 137Cs radionuklido tūrinis aktyvumas Baltijos jūros Lietuvos priekrantės paviršiniame vandenyje bei įvertinti hidrometeorologiniai parametrai. 137Cs radionuklido tūrinis aktyvumas Baltijos jūros vandenyje nėra pastovus, todėl aktualu parinkti tinkamus nustatymo metodus ir vertinti jo pokyčių tendencijas. Įvertinus radiocezio tūrinio aktyvumo pokyčius priekrantės vandenyje, galima modeliuoti ir prognozuoti taršos šaltinio atsiradimo... [toliau žr. visą tekstą]

The development of small diameter tissue engineered blood vessels (TEBVs) with low thrombogenicity, low immunogenicity, suitable mechanical properties, and a capacity to remodel to their environment could significantly advance the treatment of coronary and peripheral artery disease. Despite significant advances in the field of tissue engineering, autologous vessels are still primarily utilized as grafts during bypass surgeries. However, undamaged autologous tissue may not always be available due to disease or prior surgery. TEBVs lack long-term efficacy due to a variety of types of failures including aneurysmal dilations, thrombosis, and rupture; the mechanisms of these failures are not well understood. In vitro mechanical testing may help the understanding of these failure mechanisms. The typical mechanical tests lack standardized methodologies; thus, results vary widely. The overall goal of this study is to develop novel experimental and mathematical models to study the mechanical properties and failure mechanisms of TEBVs. Our results suggest that burst pressure tests, the current standard, are not sufficient to assess a TEBVs’ suitability as a coronary substitute; creep and/or cyclic loading tests are also required. Results from this model can help identify the most insightful experiments and quantities to be measured – ultimately reducing the overall number of experimental iterations. Improving the testing and characterization of TEBVs is critically important in decreasing the time necessary to validate the mechanical and functional responses of TEBVs over time, thus quickly moving TEBVs from the benchtop to the patient.

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ABSTRACT UNCERTAINTY ASSESSMENT IN RESERVE ESTIMATION OF A NATURALLY FRACTURED RESERVOIR ERI&Ccedil / OK, &Ouml / zlen M.S., Department of Petroleum and Natural Gas Engineering Supervisor : Prof. Dr. Fevzi G&Uuml / MRAH December 2004, 169 pages Reservoir performance prediction and reserve estimation depend on various petrophysical parameters which have uncertainties due to available technology. For a proper and economical field development, these parameters must be determined by taking into consideration their uncertainty level and probable data ranges. For implementing uncertainty assessment on estimation of original oil in place (OOIP) of a field, a naturally fractured carbonate field, Field-A, is chosen to work with. Since field information is obtained by drilling and testing wells throughout the field, uncertainty in true ranges of reservoir parameters evolve due to impossibility of drilling every location on an area. This study is based on defining the probability distribution of uncertain variables in reserve estimation and evaluating probable reserve amount by using Monte Carlo simulation method. Probabilistic reserve estimation gives the whole range of probable v original oil in place amount of a field. The results are given by their likelyhood of occurance as P10, P50 and P90 reserves in summary. In the study, Field-A reserves at Southeast of Turkey are estimated by probabilistic methods for three producing zones / Karabogaz Formation, Kbb-C Member of Karababa formation and Derdere Formation. Probability density function of petrophysical parameters are evaluated as inputs in volumetric reserve estimation method and probable reserves are calculated by @Risk software program that is used for implementing Monte Carlo method. Outcomes of the simulation showed that Field-A has P50 reserves as 11.2 MMstb in matrix and 2.0 MMstb in fracture of Karabogaz Formation, 15.7 MMstb in matrix and 3.7 MMstb in fracture of Kbb-C Member and 10.6 MMstb in matrix and 1.6 MMstb in fracture of Derdere Formation. Sensitivity analysis of the inputs showed that matrix porosity, net thickness and fracture porosity are significant in Karabogaz Formation and Kbb-C Member reserve estimation while water saturation and fracture porosity are most significant in estimation of Derdere Formation reserves.

The use of seismic methods in hard rock environments in Western Australia for mineral exploration is a new and burgeoning technology. Traditionally, mineral exploration has relied upon potential field methods and surface prospecting to reveal shallow targets for economic exploitation. These methods have been and will continue to be effective but lack lateral and depth resolution needed to image deeper mineral deposits for targeted mining. With global need for minerals, and gold in particular, increasing in demand, and with shallower targets harder to find, new methods to uncover deeper mineral reserves are needed. Seismic reflection imaging, hard rock borehole data analysis, seismic inversion and seismic attribute analysis all give the spatial and volumetric exploration techniques the mineral industry can use to reveal high value deeper mineral targets. / In 2002, two high resolution seismic lines, the East Victory and Intrepid, were acquired along with sonic logging, to assess the feasibility of seismic imaging and rock characterisation at the St. Ives gold camp in Western Australia. An innovative research project was undertaken combining seismic processing, rock characterization, reflection calibration, seismic inversion and seismic attribute analysis to show that volumetric predictions of rock type and gold-content may be viable in hard rock environments. Accurate seismic imaging and reflection identification proved to be challenging but achievable task in the all-out hard rock environment of the Yilgarn craton. Accurate results were confounded by crocked seismic line acquisition, low signal-to-noise ratio, regolith distortions, small elastic property variations in the rock, and a limited volume of sonic logging. Each of these challenges, however, did have a systematic solution which allowed for accurate results to be achieved. / Seismic imaging was successfully completed on both the East Victory and Intrepid data sets revealing complex structures in the Earth as shallow as 100 metres to as deep as 3000 metres. The successful imaging required homogenization of the regolith to eliminate regolith travel-time distortions and accurate constant velocity analysis for reflection focusing using migration. Verification of the high amplitude reflections within each image was achieved through integration of surface geological and underground mine data as well as calibration with log derived synthetic seismograms. The most accurate imaging results were ultimately achieved on the East Victory line which had good signal-to-noise ratio and close-to-straight data acquisition direction compared to the more crooked Intrepid seismic line. / The sonic logs from both the East Victory and Intrepid seismic lines were comprehensively analysed by re-sampling and separating the data based on rock type, structure type, alteration type, and Au assay. Cross plotting of the log data revealed statistically accurate separation between harder and softer rocks, as well as sheared and un-sheared rock, were possible based solely on compressional-wave, shear-wave, density, acoustic and elastic impedance. These results were used successfully to derive empirical relationships between seismic attributes and geology. Calibrations of the logs and seismic data provided proof that reflections, especially high-amplitude reflections, correlated well with certain rock properties as expected from the sonic data, including high gold content sheared zones. The correlation value, however, varied with signal-to-noise ratio and crookedness of the seismic line. Subsequent numerical modelling confirmed that separating soft from hard rocks can be based on both general reflectivity pattern and impedance contrasts. / Indeed impedance inversions on the calibrated seismic and sonic data produced reliable volumetric separations between harder rocks (basalt and dolerite) and softer rock (intermediate intrusive, mafic, and volcaniclastic). Acoustic impedance inversions produced the most statistically valid volumetric predictions with the simultaneous use of acoustic and elastic inversions producing stable separation of softer and harder rocks zones. Similarly, Lambda-Mu-Rho inversions showed good separations between softer and harder rock zones. With high gold content rock associated more with “softer” hard rocks and sheared zones, these volumetric inversion provide valuable information for targeted mining. The geostatistical method applied to attribute analysis, however, was highly ambiguous due to low correlations and thus produced overly generalized predictions. Overall reliability of the seismic inversion results were based on quality and quantity of sonic data leaving the East Victory data set, again with superior results as compared to the Intrepid data set. / In general, detailed processing and analysis of the 2D seismic data and the study of the relationship between the recorded wave-field and rock properties measured from borehole logs, core samples and open cut mining, revealed that positive correlations can be developed between the two. The results of rigorous research show that rock characterization using seismic methodology will greatly benefit the mineral industry.

O ácido ƴ-poliglutâmico (ƴ-PGA) é uma homopoliamida aniônica, biodegradável, comestível e atóxica, sintetizada por bactérias do gênero Bacillus, podendo ser utilizado nas indústrias alimentícia e de cosméticos, na medicina e no tratamento de águas residuais. Este trabalho teve como objetivo caracterizar e identificar potenciais aplicações para o ƴ-PGA obtido através do cultivo submerso de Bacillus subtilis BL53, conduzido sob condições otimizadas em trabalhos anteriores. Além disso, foi avaliado o efeito de diferentes inóculos e da adição de precursores da rota metabólica na produção do biopolímero. A melhor condição obtida foi testada em biorreatores com adição de polidimetilsiloxano (PDMS) como carreador de oxigênio, com o objetivo de aumentar a produtividade do biopolímrero. A massa molar média (Mw), obtida através de espalhamento de luz estático, na ordem de 106 g mol-1 não apresentou diferenças significativas para o biopolímero obtido após 48 e 96 h de cultivo. As análises reológicas conduzidas em viscosímetro rotacional indicaram que os polímeros obtidos após 48 e 96 horas apresentaram comportamento Newtoniano, sendo que após 96 horas a viscosidade absoluta foi maior. As análises térmicas (calorimetria diferencial exploratória e análise termogravimétrica) indicaram a temperatura de fusão (Tm) de 134 ºC e 128 ºC e o intervalo de degradação (Td) entre 120 ºC - 190 ºC e 120 ºC - 215 ºC, para os biopolímeros obtidos após 48 e 96 horas de cultivo respectivamente. O caldo LB apresentou-se como o melhor inóculo para a produção de ƴ-PGA. A adição dos precursores L-glutamina e ácido -cetoglutárico aumentou em 20 % a produção do biopolímero. A adição de 10 % de PDMS nos cultivos em biorreatores aumentou o coeficiente volumétrico de transferência de massa (KLa) e a produção e produtividade do ƴ-PGA, sendo produzidos 23.5 g L-1 do biopolímero em 24 horas de cultivo, uma produtividade aproximadamente 40 % superior às obtidas por outros autores utilizando o mesmo microrganismo. / Poly-ƴ-glutamicacid (ƴ-PGA) is an anionic, biodegradable, non-toxic and edible homopolyamide, synthesized by bacteria of the genus Bacillus, being used in food, cosmetics, medicine and waste water treatment. The aim of this study is to characterize and indentify potencial applicatiions for the ƴ-PGA obtained by submerged cultivation of Bacillus subtilis BL53, conducted under optimized conditions in previous studies. We also evaluated the effect of different inoculants and addition of precursors in the metabolic pathway of production of the biopolymer. The best condition obtained yet been tested in bioreactors with addition of polydimethylsiloxane (PDMS) as a carrier of oxygen in order to further increase the productivity of biopolymer. The average molecular weight (Mw) obtained by static light scattering, on the order of 106 g mol-1, showed no significant differences for biopolymer obtained after 48 and 96 h of cultivation. Analyses conducted in rotational viscometer indicated that biopolymers after 48 and 96 h have a Newtonian behavior, and the 96 hours had higher absolute viscosity. The thermal analysis (differential scanning calorimetry and thermo gravimetric analysis) indicated the melting temperature (Tm) as 134 ºC and 128 ºC and degradation temperature range (Td) of 120 ºC - 190 ºC and 120 ºC - 215 ºC, after 48 and 96 hours respectively. It was found that the best inoculum medium for biopolymer production was the LB broth. The addition of the precursors L-glutamine and -ketoglutaric acid increased in 20% the ƴ-PGA production. The addition of 10% of PDMS in bioreactors cultures increased the mass transfer volumetric coefficient (KLa) and the production and productivity of ƴ-PGA, being produced 23.5 g l-1 of the biopolymer in 24 hours of cultivation, a productivity about 40 % higher than those obtained by other authors using the same microorganism.