A área de visualização volumétrica engloba um conjunto de técnicas utilizadas na representação, manipulação e exibição de dados associados à região de um volume, possibilitando, assim, a exploração e melhor compreensão do interior de objetos de natureza tridimensional. Contudo, algumas limitações ainda são encontradas nessa área, como, por exemplo, a exploração de mais de um valor simultaneamente em conjuntos de dados volumétricos multivariados. Além desse desafio, outro objeto de grande interesse da comunidade científica é a exploração de volumes variantes no tempo. A complexidade nesse caso está em tratar ou processar uma quantidade muito grande de dados buscando descobrir propriedades, estruturas ou características que variam com o tempo. O presente trabalho propõe técnicas e abordagens, baseadas no conceito de projeções multidimensionais, visando dar apoio à análise de conjuntos volumétricos multivariados que variam no tempo. A primeira técnica proposta, denominada Fastmap*, possibilitou a projeção de espaços de alta dimensionalidade em fluxo contínuo. A segunda técnica apresentada, denominada RLNP, permitiu a projeção de dados por vizinhança mantendo a coerência temporal nos dados projetados, além de possuir a capacidade de projetar espaços de alta dimensão com um nível de stressbaixo. Também, propomos uma abordagem para a análise baseada em atributos, denominada Scatter Projection, que facilita a exploração focada em um atributo específico junto com a similaridade dos dados entre eles. Finalmente, propõe-se uma abordagem baseada na reprojeção de agrupamentos usando técnicas de seleção de atributos para tentar identificar melhor as estruturas internas do volume. Assim, o presente trabalho contribui no sentido de levantar e discutir limitações das técnicas disponíveis, e em seguida, buscar possibilidades de solução para tais questões, propondo técnicas e abordagens que possibilitam a exploração de grandes conjuntos de dados volumétricos multivariados, mantendo a coerência temporal / The area of volume visualization encompasses a set of techniques used for representation, manipulation and display of data associated with a region of a volume, thus enabling the exploration and understanding of the interior of three-dimensional objects. However, some limitations are still encountered in this area. For example, the simultaneous exploration of more than one value in multivariate volumetric datasets. Beyond this challenge, another issue of great interest to the scientific community is the exploration of time-varying volumes. The complexity of this case lies in treatment or processing of a very large amount of data, seeking to discover properties, structures, or characteristics that may vary in time. This work proposes techniques and approaches, based on the concept of multidimensional projections, in order to support multivariate volumetric analysis of time varying data sets. The first technique proposed, called Fastmap*, enables the projection of high dimensional streaming data. The second technique presented, called Recursive Laplacian-based Neiboorhood Projection, allows the projection of data sets based on neighborhoods, maintaining the temporal coherence in the projected data, besides having the ability to project highdimensional spaces with a low level of stress. Also, we propose an approach for the analysis of specific attributes, referred to as Scatter Projection, which facilitates the exploration focused on a specific attribute and on the similarity between them. Finally, we propose an approach based on reprojection of groups using feature selection techniques for better identification of internal structures of the volume. Thus, this study contributes towards surveying and discussing limitations of the area, and then seeks ways of solving these issues, proposing techniques and approaches that enable the exploration of multidimensional volumetric time varying data sets, maintaining the temporal coherence

abstract: Drainage flow of a viscous compressible gas from a semi-sealed narrow conduit is a pore-scale model for studying the fundamental flow physics of fluid recovery from a porous reservoir without using fluid injection. Thermal effect has been routinely neglected for these flows in the traditional petroleum engineering literature. Since the motion is entirely driven by volumetric expansion, temperature change always accompanies the density change. This thesis examines such thermal effects on the drainage flow. Thermal drainage flow is first studied by simultaneously solving the linearized continuity, momentum and energy equations for adiabatic walls. It is shown that even in the absence of an imposed temperature drop, gas expansion induces a transient temperature decrease inside the channel, which slows down the drainage process compared to the isothermal model and Lighthill’s model. For a given density drop, gas drains out faster as the initial-to-final temperature ratio increases; and the transient density can undershoot the final equilibrium value. A parametric study is then carried out to explore the influence of various thermal boundary conditions on drainage flow. It is found that as the wall transitions from adiabatic to isothermal condition, the excess density changes from a plane wave solution to a non-plane wave solution and the drainage rate increases. It is shown that when the exit is also cooled and the wall is non-adiabatic, the total recovered fluid mass exceeds the amount based on the isothermal theory which is determined by the initial and final density difference alone. Finally, a full numerical simulation is conducted to mimic the channel-reservoir system using the finite volume method. The Ghost-Cell Navier-Stokes Characteristic Boundary Condition technique is applied at the far end of the truncated reservoir, which is an open boundary. The results confirm the conclusions of the linear theory. / Dissertation/Thesis / Doctoral Dissertation Mechanical Engineering 2020

This research includes the potential for resistance and the expansion that the soil presents, this evaluation was carried out through CBR tests. The soil cement technique was used to improve the physical and mechanical characteristics; this process consists in mixing the material with Portland cement type I. That combination forms soil cement 10%, 15% y 20%, which present an increase of the CBR (max: 138.7% and min: 91.9%) achieving a type of extraordinary subgrade to resist the structure of the pavement and a reduction of 7.18% in the expansion of the samples.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22476号 / 農博第2380号 / 新制||農||1074(附属図書館) / 学位論文||R2||N5256(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 中村 公人, 教授 星野 敏, 教授 藤原 正幸 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Volumetric visualization is something that has become more interesting during recent years. It has been something that was not feasible in an interactive environment due to its complexity in the 3D space. However, today's technology and access to the power of the graphics processing unit (GPU) has made it feasible to render volumetric data interactively. This thesis explores the possibilities to create and render large volumetric terrain using an implementation of Marching Cubes on the GPU. With the advent of general-purpose computing on the GPU (GPGPU) it has become far easier to implement tradition CPU tasks on the GPU. By utilizing newly available functions in DirectX it is possible to create an easier implementation on the GPU using global buffers. Three implementations are created inside the Unity game engine using compute shaders. The implementations are then compared based on creation time, render times and memory consumption. Then a deeper analysis of the time distribution is presented which suggests that Unity introduces some overhead since copying buffers from GPU to CPU is time consuming. It did however improve render times due to its culling and optimization techniques. The system could be used in applications such as games or medical visualization. Finally some future improvements for culling and level of detail (LOD) techniques are discussed. / Volumetrisk visualisering är en teknik som har fått mer uppmärksamhet dom senaste åren. Det har varit någonting som inte har varit rimligt att göra i en interaktiv miljö på grund av dess komplexitet i 3D rymden. Med dagens teknik och tillgänglighet till grafikkortet (GPU) är det nu möjligt att rendera volumetrisk data i en interaktiv miljö. Den här uppsatsen utforskar möjligheterna till att skapa och rendera stora terräng landskap genom en implementering av Marching Cubes på GPU:n. Med framkomsten av general-purpose computing på grafikkortet(GPGPU) har det blivit lättare att programmera på GPU:n. Genom att använda nya funktioner tillgängliga i DirectX är det möjligt att skapa en enklare implementering på GPU:n som använder sig av globala buffrar. Tre implementeringar har skapats i spelmotorn Unity som använder compute shaders. Implementeringarna är sedan jämförda baserad på tid för generering av terräng, renderings tid samt minnes konsumption. Detta följs av en djupare analys av tidsdistribueringen för skapandet som pekar på att Unity håller tillbaka systemets hastiget pga kopierande av minne från GPU:n till CPU:n. Renderingstiden blev dock bättre med hjälp av den inbyggda culling-teknikerna och optimerings tekniker. Detta system skulle kunna appliceras inom spel eller medicinsk visualisering. Slutligen diskuteras framtida förbättringar för culling-tekniker och level of detail (LOD) tekniker.

This thesis improves on the design of the Optical Trap Display (OTD), presented in 2018 [1]. Contributions include: real time animation; single beam, multiparticle suspension, point primitive anisotropic scattering, and virtual image approximation. First, real time animation was demonstrated on the OTD for the first time in full color at up to 30Hz refresh. Second, multi-particle systems allow for scaling of the display by a multiplicative factor, potentially up to orders of magnitude greater than the first OTD. Third, anisotropic scattering of point primitives was shown for individual suspended particles and multiple simultaneously suspended particles. Fourth, virtual images have been previously considered impossible in volumetric displays but by using perspective projections we have shown in simulation and experiment for the first time that an effect similar to a virtual image can be created.

The purpose of this thesis was to find and implement an adaptive method, based on given data and hardware, for selecting different level-of-detail whilst preserving visual quality to the best extent possible. Another important aspect of the new method was that it had to be performance effective, since the target platform was an interactive direct volume rendering application. The project was targeted towards memory restricted systems in which it has previously been impossible to render large-scale volumetric datasets. The previous state of the target platform supports two detail levels: full and half, and does not implement any kind of prioritisation when selecting the level-of-detail of bricks. Apart from failing to render parts of the datasets, the old implementation is also lacking in that the top of the dataset always has the lowest prioritisation, which can prove problematic for certain datasets. An adaptive method which determines a suitable number of detail levels at run-time has been implemented. The new implementation has also reworked the way bricks are prioritised during rendering. The proposed algorithm prioritises bricks holding surface information as well as bricks that match the transfer-function configuration well. The results show that the proposed method is able to render large-scale datasets in limited environments whilst maintaining interactive frame-rates. The new brick selection algorithm is a step in the right direction towards solving the issue with parts of the dataset not being prioritised.

No description available.

Freeze-drying (lyophilization) is a drying process which is used to remove water from heat sensitive products, usually for the purpose of preservation. By removing water, the product becomes more stable at room temperature. This is a common process in the pharmaceutical industry because freeze-drying offers the advantage of drying at low temperatures and producing very low residual moisture contents. Often the materials dried in this manner are heat sensitive and require the highest possible quality. However, freeze-drying is a very slow process, often requiring 24 to 48 hours. During the process, vacuum pumps and refrigeration systems run continuously, making freeze-drying a very expensive process. The goal of this project was to show that volumetric heating can be used in pharmaceutical freeze-drying and that this mode of heating offers some advantages. There were two approaches taken to the work, one experimental and one analytical. The experimental approach was broken into two phases, one focused on comparing microwave and conventional freeze-drying and the other focused on demonstrating the advantages of volumetric heating. In the analytical approach, a mathematical model was used to confirm the trends observed in phase II of the experimental work. Experiments were conducted in a conventional laboratory freeze-dryer and the drying rate results were compared to the results obtained with an experimental microwave freeze-drying apparatus. Experiments were also conducted with the vaccine strain <i>A. pleuropneumoniae</i>. A viability study was conducted, comparing the viability loss caused by each process. The viability study showed a slightly higher viability loss for the microwave process. A comparison of drying curves showed that the microwave process resulted in a slight improvement in primary drying time: 2.5 hours for the microwave process compared to 3 hours for the conventional process. There was a significant difference in overall drying times: 4 hours for the microwave process compared to 11 hours for the conventional process. This result was caused by a lower residual moisture content at the start of secondary drying and a higher secondary drying temperature for the microwave process. Experiments were also conducted to show that using lower chamber pressure results in higher drying rates. This is not the case in a conventional freeze-dryer since heating is dependent on the chamber pressure in the low pressure environment of freeze-drying. Thus, an advantage of volumetric heating was demonstrated. The results show that a modest increase in pressure, from 0.05 to 0.3 Torr, caused a one third reduction in primary drying time. The mathematical model developed in the analytical work relied on the D'Arcy equation to describe the flow of vapor in the porous dried layer. The results of the model confirm trends seen in the measured temperature and weight profiles. Analyzing the effect of varying the chamber pressures shows that lowering the pressure in the range of 1 to 0.01 Torr results in a significant increase in drying rate giving as much as a two thirds reduction in drying time for the case studied. A model incorporating mass transport equations derived from the dusty gas model was also presented. This model offers the benefit of a more accurate prediction of mass transport through the porous dried layer. NOTE: (09/2008) An updated copy of this ETD was added after there were patron reports of problems with the file. / Ph. D.

The nature of chemical reactions taking place during the titration of dilute Al solutions in the presence of either chloride or sulfate were examined by refining the apparent Al hydrolysis products assuming the presence of solution species with n (OH/Al mole ratio) equal to 1, 2, 2.5, 3 and 4. The second and third hydrolysis products for Al were refined by comparison of calculated titration patterns to those observed for 10⁻³, 10⁻⁴ and 10⁻⁵ M Al in 1 M, 0.1 M and 0.01 M KCl. A large degree of polynuclear character of Al solutions was found even at Al concentrations as low as 10⁻⁵ M. The n value and size of the polynuclear complexes are affected by Al concentration. The concentration constant, pQ₁₃ is found to be at least 17.4-17.7. It is concluded that the mononuclear Al(OH)₂ species is never significant. Use of statistical analysis of the data and graphical methods did not result in consistent data for polymer size determinations. The lower pQ values for mononuclear Al hydrolysis are explained by the structural instability of the mononuclear complexes. The bond strengths required for the bonds in the second and third hydrolysis complexes are often larger than those allowed for octahedral coordination. For that reason, the pQ values would be lower than calculated by extrapolation between the stable first and fourth hydrolysis constants. A new polynuclear complexation mechanism for Al is proposed to account for the high concentration of high n value polynuclear species in the titration refinements. The proposed linear l double chain structure has a structure consistent with boehmite and diaspore. This structure differs from the linear single chain and ring based polynuclear structures by the presence of rows of three coordinated oxygens in the bond central chain and rows of two and one coordinated oxygens along the plane edges. A rearrangement of internal charge in this structure is proposed in which part of the charge is removed from the three coordinated oxygens to result in an uncharged hydroxyl with the charge shifted to the one coordinated site neutralizing the hydroxyl. This results in a general formula for the polynuclear structure of (Al(OH)₃)_x(Al(OH)₂)₂²⁺. This structure results in a higher n value for a lower number of Al than does the other polynuclear complexation schemes and therefore explains the presence of high n value polymers in unaged Al solutions which would have required polymers of greater than a hundred Al cations. The observed presence of a second Al plateau on titration patterns with Al concentrations greater than 5 x10⁻⁵ M could not be the result of the onset of precipitation as earlier proposed. It is proposed that at a pH in the 6 to 7 range, a change of some of the one coordinated sites on the edge of the larger polynuclear and precipitant structures from water to hydroxyls results in a change in net edge charge from net positive to net negative which causes an increased rate of crystal growth due to the unlike charge between the edges and the smaller polynuclear and mononuclear complexes. The refinement of Al titration data in K₂SO₄, provide pQ values one to three pQ units lower than those obtained from equivalent KCl solutions. A catalytic mechanism is proposed in which Al polymerization is facilitated by the formation of mononuclear Al hydroxy sulfate complexes which combine together to form nonsulfate containing polynuclear complexes. The increased hydrolyzed concentration and lower ionic charge resulting from these complexes would increase the rate of polymerization in these systems. Evidence for the presence of mononuclear hydroxy sulfate complexes comes from the better fit for titration patterns in sulfate systems which would not have been observed for increased polymerization alone. / Ph. D.