En este trabajo presentamos un nuevo algoritmo para simulación de medios granulares densos que incluye partículas estáticas en presencia de gravedad. El modelo consiste en esferas duras inelásticas, para el cual contamos con un algoritmo de simulación eficiente. Extendemos la descripción de las partículas de manera de simular sólo las relevantes a la dinámica macroscópica del sistema. Presentamos tres casos de estudio: deposiciones sobre un suelo estático, avalanchas en un plano rugoso inclinado y el flujo en un tambor rotante. Estudiamos cómo dependen los observables físicos de los parámetros del algoritmo en tres casos: la fracción de empaquetamiento de esferas iguales, el ángulo de detención para avalanchas sobre un suelo rugoso y el perfil de velocidad en un tambor rotante. Los resultados obtenenidos son prometedores y muestran que el modelo de simulación conducida por eventos es útil para simular flujos densos, siempre y cuando se disipe energía de forma adecuada. La nueva extensión permite simular sistemas de interés en un tiempo computacional mucho menor que con métodos actuales. Concluimos mostrando diferentes sistemas que pueden ser simulados con nuestro algoritmo y proponemos futuras lineas de investigación.

In the discipline of geotechnical Engineering the majority of finite element program users is familiar with the hyperbolic soil model. The input parameters are commonly obtained from a series of triaxial tests. For cohesionless soil ls however, today's sampling techniques fail to provide undisturbed soil specimen. Furthermore, routine triaxial tests can not be carried out on soils with grains exceeding 10 - 15 mm in size.

In the natural world, animals encounter terrestrial environments that range from stiff to compliant. Terrestrial locomotion across natural surfaces is highly complex, as animals must overcome substrate heterogeneity to maintain locomotor performance essential for survival (e.g., catching prey, escaping predators). Within these environments, natural substrates such as sand, gravel and cobbles, are known as granular media: a collection of discrete particles varying in material properties and behaviors when exposed to forces of different magnitude. On a single step, granular media alternates between solid and fluid-like states with potentially drastic consequences on running performance. Additionally, granular substrates at different inclinations are ubiquitous in natural environments, such as sand dunes in the desert. At the angle of repose—the maximum angle providing sand dunes their typical shape—granular media will fluidize with the slightest stress, rendering running at these angles extremely challenging. Unlike locomotion through fluids (e.g., swimming and flying), governed by the Navier-Stokes equations, how foot kinematics instigate state changes on granular media is still poorly understood, yet it is critically important for survival. The goal of my dissertation is to determine how foot use affects foot-ground interactions on granular media, with a particular focus on incline locomotion. The objectives of my dissertation are threefold: evaluate the effects of granular inclines on 1) performance and above-surface limb and foot kinematics, 2) sub-surface foot kinematics, and 3) the dynamics of foot-ground interactions using computational simulations. To fulfill these objectives, I examined three lizard species: a sand specialist (Callisaurus draconoides), a desert generalist (Crotaphytus bicinctores), and a fluid specialist (Basiliscus vittatus), selected because they have similarly shaped feet, so that differences detected among performance are due to foot kinematics rather than morphology. I ran these lizard species on a level and inclined granular trackway, while videorecording them at 500 fps using a high-speed video camera (light video) and a bi-planar high-speed fluoroscopy system (X-ray video) for the above-surface kinematics and the subsurface kinematics, respectively. Running trials were used to quantify running speed, basic stride, foot impact, and sub-surface foot kinematics, to implement on computational simulations of foot-shaped intruders entering a volume of particles to quantify force response at the particle scale. Sand specialists not only outperformed non-specialists on the incline, but maintained running speed compared to the level despite presenting some foot slip. While no significant differences across species were found for basic stride and impact kinematics, only sand specialists shifted foot intrusion angle into incline granular media to angles close to perpendicular to the substrate. At the subsurface, sand specialists maintained a stiffer foot similar to generalists, and intruded their feet shallower similar to fluid specialists. However, only sand specialists maintained toe spacings close to 6 mm on level and incline, similar to a study on intruder spacings showing peak force generation. The ground force response exhibited by the sand specialist lizard foot model revealed that by hitting the particles fast (0.7 m/s) and shallow, almost perpendicular to the substrate, toe first, with stiff feet, and toe spacings close to 6 mm, sand specialists are likely taking advantage of the inertial behavior of the particles at the angle of repose. Essentially, by paddling through the substrate’s fluid-like behaving surface, sand specialists run significantly faster than fluid specialists and generalists. My dissertation demonstrates the significance of surface and subsurface kinematics strategies to understand foot-ground interactions, especially on angled yielding substrates, contributing with knowledge to the terradynamics field and elucidating significant applications in bioengineering, bioinspiration and robotics. / Biology

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As computer generated special effects play an increasingly integral role in the development of films and other media, simulating granular material continues to be a challenging and resource intensive process. Solutions tend to be pieced together in order to address the complex and different behaviors of granular flow. As such, these solutions tend to be brittle, overly specific, and unnatural. With the introduction of a holistic 3-phase granular simulation, we can now create a reliable and adaptable granular simulation.Our solution improves upon this hybrid solution by addressing the issue of particle flow and correcting interpenetration amongst particles while maintaining the efficiency of the overall simulation. We achieve this by projecting particles onto a 2D manifold and implementing density correction using a quadratic solver. Particle updates are projected back into 3D to spread the particles apart on each frame.Keywords:

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O objetivo principal desta pesquisa foi comparar o desempenho de dois reatores anaeróbios híbridos de biomassa imobilizada (RAHBI), em escala de laboratório, no processamento da vinhaça de cana-de-açúcar. Um (reator 1) recebendo vinhaça sem tratamento prévio e outro (reator 2) processando vinhaça previamente submetida à coagulação, utilizando-se de um biopolímero experimental a base de cálcio. Os reatores foram construídos em acrílico, com volume de 1,5 litros cada, provido de sistema de recirculação com razão igual a 3. A operação dos reatores foi dividida em duas etapas: a primeira, com duração de 69 dias, teve seu fim caracterizado por um colapso apresentado pelo reator 2. A segunda fase, com duração de 37 dias, onde se observou outro colapso. O principal parâmetro de controle no monitoramento dos reatores foi a quantificação de matéria orgânica, em termos de Demanda Química de Oxigênio (DQO). Durante a Fase I, o reator 1 apresentou eficiência de remoção média de 82,9 ± 4,4% , e o reator 2 de 72,2 ± 18,1%. A carga orgânica volumétrica (COV) média aplicada para o reator 1, durante esta fase, foi de 5,3 ± 1,3 kg DQO/\'M POT.3\'d, e para o reator 2 foi de 5,3 ± 1,6 kg DQO/\'M POT.3\'d. O colapso ocorrido no reator 2 foi evidenciada pelo decréscimo acentuado da eficiência de remoção, chegando a 33,7%. Durante a Fase II, o reator 1 apresentou eficiência de remoção média de 77,5 ± 9,4% , e o reator 2 de 79,2 ± 9,7%. A carga orgânica volumétrica (COV) média aplicada para o reator 1, durante esta fase, foi de 5,1 ± 2,4 kg DQO/\'M POT.3\'d, e para o reator 2 foi de 5,0 ± 2,3 kg DQO/\'M POT.3\'. Ao final desta fase o reator 1 apresentou eficiência de remoção de 80,9%, e o reator 2 65.8%. Foram analisados, também, alcalinidade e produção de metano (\'CH IND.4\'). Durante todas as fases, a alcalinidade dos dois reatores esteve acima de 1000 mg \'CA\'CO IND.3\'/l, indicando estabilidade, em relação a este parâmetro, dos reatores. A produção de \'CH IND.4\' do reator 1 foi de 0,0507 ± 0,0232 l \'CH IND.4\'/h e 0,0838 ± 0,0326 l \'CH IND.4\'/h nas fases I e II, respectivamente. Para o reator 2, esta produção foi de 0,0307 ± 0,0137 l \'CH IND.4\'/h e 0,0800 ± 0,0297 l \'CH IND.4\'/h, para as fases I e II, respectivamente. Foram feitos ensaios de resistência mecânica dos grânulos, análise de microscopia eletrônica de varredura (MEV), Espectrometria de Energia Dispersiva de Raios-X (EDS) e análise da comunidade microbiana, empregando técnicas de biologia molecular. Os testes de resistência mecânica dos grânulos indicam que os grânulos contidos no inóculo, reatores 1 e 2 possuem resistência à desintegração. As análises de MEV e EDS indicam a presença do elemento cálcio com aproximadamente 22% para o inóculo, 39% para o reator 1 e 50% para o reator 2, na massa dos elementos analisados das amostras de grânulos. As análises de biologia molecular indicaram similaridades entre os reatores 1 e 2 de 66,5 e 58%, para os domínios Bacteria e Archea, respectivamente. Desta forma, supõe-se que esta diferença da biota entre os reatores não estaria contribuindo para a falha conferida no reator 2. / This research aimed at compare the performance of two hybrid anaerobic immobilized biomass (HAIB), in laboratory scale, processing vinasse from sugar cane alcohol destilery. Reactor 1 received vinasse without pre-treatment. Reactor 2 processed coagulated vinasse using a calcium-based biopolymer as coagulant. The two reactors were built in acrylic, with a volume of 1,5 liters each. The recirculation flow rate was 3. The operation of the reactors was divided in two phases: first, lasting 69 days, came to an end characterized by a failure (collapse) presented by the reactor 2. The second phase, lasting 37 days, came to an end characterized by another collapse. The main control parameter in the monitoring of the reactors was the quantification of organic matter in terms of COD. During Phase I, the reactor 1 showed average removal efficiency of 82,9 ± 4,4%, and the reactor 2 72,2 ± 18,1%. The organic loading rate (VOC) average applied to reactor 1, during this phase, was 5,3 ± 1,3 kg DQO/\'M POT.3\'d, and 5,3 ± 1,6 kg DQO/\'M POT.3\'d for the reactor 2. The failure occurred in the reactor 2 was evidenced by the sharp decrease of removal efficiency, reaching 33.7%. During Phase II, the reactor 1 showed average removal efficiency of 77,5 ± 9,4%, and the reactor 2 79,2 ± 9,7%. The average VOC applied to reactor 1, during this phase, was 5,1 ± 2,4 kg DQO/\'M POT.3\'d, and 5,0 ± 2,3 kg DQO/\'M POT.3\'d for reactor 2. At the end of this phase, the reactor 1 showed a removal efficiency of 80.9%, and the reactor 2 65.8%. Has also been analyzed, alkalinity and methane (\'CH IND.4\'). During all the phases, the alkalinity of both reactors was above 1000 mg \'CA\'CO IND.3\'/l, indicating stability in the reactors. The production of \'CH IND.4\' was 0.0507 ± 0.0232 l \'CH IND.4\'/h and 0.0326 ± 0.0838 l \'CH IND.4\'/h in phases I and II, respectively. For the reactor 2, the production of \'CH IND.4\' was 0,0307 ± 0,0137 l \'CH IND.4\'/h e 0,0800 ± 0,0297 l \'CH IND.4\'/h for the phases I and II, respectively. Assays were performed in mechanical granules strength, analysis of scanning electron microscopy (SEM), Energy Dispersive Spectroscopy X-ray (EDS) and analysis of the microbial community, using molecular biology techniques. The tests of mechanical of granules strength indicate that the granules contained in the inoculum, reactors 1 and 2 are resistant to disintegration. The SEM and EDS analysis indicated the presence of calcium element with approximately 22% inoculum, 39% for reactor 1 and 50% for reactor 2, in the mass of the elements analyzed samples of granules. The microbial community analyzes indicated molecular similarity between the first and second reactor of 66.5 and 58% for Bacteria and Archea domain, respectively. Thus, it is assumed that the difference between the biota of the reactors would not be contributing to the failure given in the reactor 2.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-07-14T12:51:11Z No. of bitstreams: 1 Gabriel Cristiano Kuhn_.pdf: 1527987 bytes, checksum: dd028ed9d9ded68e948299bcc1bfb746 (MD5) / Made available in DSpace on 2016-07-14T12:51:11Z (GMT). No. of bitstreams: 1 Gabriel Cristiano Kuhn_.pdf: 1527987 bytes, checksum: dd028ed9d9ded68e948299bcc1bfb746 (MD5) Previous issue date: 2016-04-27 / FAPERGS - Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul / Válvula L é um tubo em forma de L destinado a conduzir partículas sólidas entre dois reservatórios. Este dispositivo usa injeção de um fluido e a sua geometria para o controle da vazão dos sólidos. A aplicação deste tipo de válvula não mecânica se dá em processos que visam o transporte de partículas, como linhas de transporte pneumático e reatores de leito circulante. O objetivo deste trabalho é desenvolver uma correlação para a vazão mássica de sólidos através da análise dos números adimensionais, calculados com base em variáveis do processo, e dados experimentais. Com uma correlação mais precisa torna-se mais fácil o controle e o projeto de uma válvula L. Este estudo desconsidera a influência dos reatores, levando em conta apenas a influência da geometria da válvula, a variação da injeção de ar e as propriedades das partículas. A bancada de ensaios foi projetada com duas válvulas L (diâmetros de 34 e 70 mm) feitas de acrílico. Foram utilizadas esferas de vidro (diâmetro Sauter 0,8 mm, massa específica efetiva 1580 kg/m3, grupo D da classificação Geldart), conduzidas por ar comprimido. Aplicando-se o teorema de PI de Buckingham às variáveis importantes do processo, três números adimensionais foram obtidos. Após uma bateria de testes, estes números adimensionais foram calculados para várias condições de ensaios. Com base nos dados experimentais, obteve-se uma equação de ajuste e uma correlação para o fluxo de sólidos. Calculou-se seis correlações, porém é possível dizer que apenas três descrevem o processo, mesmo que com alguma incerteza. Para as válvulas de 34 mm foi possível observar a máxima taxa de sólidos, ou seja, qualquer incremento na vazão injetada resulta em uma diminuição do escoamento de sólidos. / L valve is a right angled, L shaped pipe applied to transfer solids between two vessels. The device uses gas injection and pipe geometry for controlling the flow of particulate solids. This kind of non-mechanical valve is used in processes as pneumatic transport lines and circulating fluidized beds. This study aims to develop a new correlation to the solids mass flow rate through dimensional analysis, experimental data and equation fitting. An accurately way to estimate the flow of solids makes easier the valve design and control. This study does not consider the influence of the reactors that an L valve connect, in other words, this approach is limited to the influence of L valve geometry, gas injection and particle properties. A test section was built, comprising two valve diameters (acrylic pipes of 34 and 70 mm). Glass beads will be used as solids (Sauter diameter 0.8 mm, bulk density 1580 kg/m3, group D of Geldart classification) conveyed by air. Dimensionless numbers were calculated (by Buckingham PI theorem) from the variables of the process, then an experimental program was done. Based on experimental data, π_1, π_2 and π_3 values were calculated for various test conditions. Based on the experimental data, an equation fit and a correlation to the solids mass flow rate were obtained. Six correlation were calculated but only three are able to describe the L valve process with a minimum accuracy. Maximum solids flow were achieved for 34 mm L valve, in other words, if aeration rate is increased beyond this point, solids flow decreases.

La presente investigación propone la alternativa de uso de caucho reciclado con el fin de mejorar el diseño de la mezcla para pavimento a nivel de base granular del material de la planta de Chupuro , con el propósito predominante de estabilizar la base del material estudiado , para así minimizar el deterioro del pavimento causado por cargas de tránsito y los permanentes y continuos mantenimientos que en la actualidad se vienen dando a los pavimentos , es por ello que se analizó la incidencia el material en el valor de CBR . El objetivo de esta investigación es darle uso al caucho reciclado obtenido de los neumáticos, cámaras de bicicletas, recortándolos de manera manual y rustica en pequeñas dimensiones de tamaño de una fibra para facilitar su posterior incorporación en el material de la base granular en pavimentos.