Made available in DSpace on 2014-10-09T12:24:36Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:17Z (GMT). No. of bitstreams: 1 00620.pdf: 5067176 bytes, checksum: bb1e5d586459379a88e026418268d501 (MD5) / Thesis (Ph.D.) / IEA/T / University of Illinois, Urbana - Champaign

Orientador: Marco Aurélio Cremasco / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-22T15:45:04Z (GMT). No. of bitstreams: 1 Amaral_RodrigodeLima_M.pdf: 13350752 bytes, checksum: 3d9431f6b791b14e373098ba02fc3d5c (MD5) Previous issue date: 2013 / Resumo: A técnica de Velocimetria por Imagem de Partícula (PIV) é empregada na caracterização do campo de velocidade em diversos tipos de escoamentos. A técnica PIV do tipo tomográfica (Tomographic PIV ou PIV Tomográfica) possibilita a determinação do campo de velocidade do fluido em três dimensões, utilizando partículas que seguem fielmente o fluxo desse fluido. A técnica faz uso de visualizações simultâneas, perspectivas diferentes, das partículas, iluminadas por laser, e sua reconstrução 3D como uma distribuição de intensidade de luz por meio da tomografia óptica para determinação dos vetores velocidades por correlação cruzada 3D. A relação entre a imagem (projeção) e as coordenadas do espaço físico (o objeto) é estabelecida por um procedimento de calibração. Cada câmera registra imagens de um alvo calibração em várias posições de profundidade em todo o volume. A partir dessas imagens o procedimento de calibração retorna uma função de mapeamento. Um procedimento de autocalibração é feito para diminuir o erro da calibração. A autocalibração é uma técnica para a correção a posterior do desalinhamento do sistema de câmeras e pode melhorar significativamente a precisão da reconstrução tomográfica, o que pode acontecer devido a uma calibração imprecisa ou um leve movimento das câmeras. Esta Dissertação faz uma avaliação experimental do efeito da autocalibração volumétrica para a técnica PIV Tomográfica na investigação da velocidade em uma seção riser de um leito fluidizado circulante. Foi utilizada a técnica PIV Tomográfica, desenvolvida pela LaVision, com 4 câmeras (sensor CCD) e um sistema laser Nd:YAG. Foi desenvolvida uma estrutura que permite o deslocamento das quatro câmeras, nas três direções, e uma estrutura para o sistema laser. Os erros de calibração no volume ficaram entre 0,670 e 1,073 pixel e depois da autocalibração ficaram abaixo de 0,04 pixel. Foi analisado também o campo de velocidade instantânea (t = 71 s), campo de velocidade média no plano Z = 0 mm, flutuações da velocidade ao longo do raio do riser (X = - 40, -20, 0, 20 e 40 mm) para Y = -15, 0, +15 mm e Z = -2, 0 e +2 mm. O erro de calibração interfere diretamente na qualidade do volume reconstruído e consequentemente no cálculo do deslocamento das imagens de partículas de forma que o procedimento de autocalibração se torna necessário / Abstract: Particle Image Velocimetry (PIV) technique is employed in the characterization of velocity fields in different types of flow. PIV technique of type tomographic (Tomographic PIV) enables the determination of the velocity field of fluid in three dimensions by using particles which reliably follow the flow of fluid. The technique makes use of simultaneous views, different perspectives of particles illuminated by laser, and its 3D reconstruction as a light intensity distribution by optical tomography for determination of velocity vectors by 3D cross-correlation. The relationship between the image (projection) and the coordinates of physical space (the object) is established by a calibration procedure. Each camera records images of a calibration target in various positions throughout the depth volume. From these images the calibration procedure returns a mapping function. A self-calibration procedure is done to decrease the error of calibration. The self-calibration is a technique of a-posteriori correction of misalignment of the camera system and can significantly improve the accuracy of tomographic reconstruction, which can happen due to an inaccurate calibration or a slight movement of the camera. This Dissertation makes an experimental evaluation of the effect of volume self-calibration for Tomographic PIV technique in the investigation of velocity field on a short riser section of a circulating bed. Tomographic PIV technique used in this work was developed by LaVision with 4 cameras (CCD sensor) and Nd:YAG laser system. A structure that allows the displacement of the four cameras in the three directions and a structure for laser system were developed. The calibration errors in volume were between 0.670 and 1.121 pixels and after self-calibration were less than 0.04 pixels. It was also analyzed the instantaneous velocity field (t = 71 s), average velocity field in the plane Z = 0 mm, the velocity fluctuations along the radius of the riser (X = - 40, -20, 0, 20 and 40 mm) for Y = -15, 0, +15 mm and Z = -2, 0 and +2 mm. Calibration error directly affects the quality of the reconstructed volume and consequently the calculation of particle images displacement and the self-calibration procedure is necessary / Mestrado / Engenharia de Processos / Mestre em Engenharia Química

Abstract Good postural stability is needed during most activities in daily life. Balance can be improved with specific training programmes in physiotherapy. The goals of treatment differ, depending on the subject's age and disorders. In clinical practice, postural stability is commonly evaluated by scaled functional tests or by recording body sway on a platform. On the basis of therapeutic modalities, information of separate movements of body segments would be important. The data might be useful in developing balance evaluation and training programmes in physiotherapy. The aim of this project was to present one method and to estimate its reliability and validity in studying the movements of separate body segments in postural control. In addition, the association between age, gender and anthropometric factors and the movements of separate body segments during quiet stance with the eyes open and closed were studied in a group of healthy subjects. A method was developed to measure the body movements during standing with a motion analysis system, and the reliability of body movement measurements was evaluated. The validity of the motion analysis measurements was evaluated to compare the balancing body measurements during stance on two legs and on one leg obtained with a motion analysis system and a platform. In cross-sectional studies, 100 healthy randomly selected subjects were stratified into ten groups (by age and gender). The body movements of all subjects standing on two legs with the eyes open and closed were measured using a motion analysis system and calculated as maximal and total movements. The movement velocities and accelerations were analysed and compared between the eyes open and eyes closed conditions. The associations between movement values and age and gender were analysed. In addition, the body anthropometrics of the subjects were measured and the relations between the body characteristics and the body balancing movements were calculated using regression analysis. The results showed that motion analysis can be used in measuring body movements in postural stability. Better reproducible balance measurement results are obtained with the total movement values than with the maximal amplitude values. In a comparison of the parameters used in a validity study, motion analysis and platform seemed to reflect the same aspect of balance, although the views of measurement were different. During standing on two legs with the eyes open, there was a statistically significant difference in the maximal anterior-posterior head movement and in the vertical navel movement between the age groups, but the results did not show other statistically significant differences between the balancing movements of separate body segments of the groups or between the balance measurement values of men and women in standing on two legs with the eyes open and closed. It seems that healthy female and male subjects control their stance with quite similar ranges of body adjustment. Body characteristics had slight but considerable effects on the variations of body balancing movements in standing on two legs with the eyes open, but almost none in the eyes-closed conditions. There were differences in the results between the male and female groups. In standing on two legs with the eyes closed, all the measured body parts except the ankles had significantly higher maximal velocity and acceleration values than in standing with the eyes open. The effect of visual information on balancing the body seems to be essential. The results indicated that the motion analysis system is also a useful tool in further balance studies, but the methods of analysis need to be developed. Postural stability should be evaluated and practised even in more demanding balance performances. Movement speed and the special role of each body part in maintaining balance should be paid attention.

Despite significant recent progress, dense, time-resolved imaging of complex, non-stationary 3D flow velocities remains an elusive goal. This work tackles this problem by extending an established 2D method, Particle Imaging Velocimetry, to three dimensions by encoding depth into color. The encoding is achieved by illuminating the flow volume with a continuum of light planes (a “rainbow”), such that each depth corresponds to a specific wavelength of light. A diffractive component in the camera optics ensures that all planes are in focus simultaneously. With this setup, a single color camera is sufficient to track 3D trajectories of particles by combining 2D spatial and 1D color information. For reconstruction, this thesis derives an image formation model for recovering stationary 3D particle positions. 3D velocity estimation is achieved with a variant of 3D optical flow that accounts for both physical constraints as well as the rainbow image formation model. The proposed method is evaluated by both simulations and an experimental prototype setup.

This thesis presents a detailed study of recent changes in the mass balance and dynamics of Penny Ice Cap (PIC), and projects its evolution under a warming climate. Mass losses from 2005-2014 were quantified from airborne altimetry elevation change measurements, and adjusted for vertical ice motion caused by firn compaction and/or ice dynamics. Mass loss from PIC increased four-fold between the mid-1990s (-1.3 ± 0.7 Gt a-1) and 2005-2013 (-5.4 ± 1.9 Gt a-1). The adjustment calculations indicate that mass loss may be overestimated by 19% if vertical motion is not properly accounted for. The velocity response to increased surface melt was quantified using satellite imagery and historical ground measurements from Highway Glacier, on the southern part of PIC. Over the period 1985-2011, the six largest outlet glaciers on the ice cap decelerated at an average rate of 21 m a-1 over the 26 year period (0.81 m a-1), or 12% decade-1. Highway Glacier decelerated by 71% between 1953 and 2009/11. The recent slowdown of outlet glaciers has coincided with increases in mass loss and an inferred reduction in basal sliding. The ice-cap-wide mass balance was modeled from 1958 to 2099 with an enhanced temperature index model. Since the mid-1990s mass balance rates over PIC have become increasingly negative. Peak mass loss is projected to occur in the late 2070s and PIC is expected to lose 16-20% of its 2014 ice volume by 2099 assuming a moderate climate warming scenario (RCP4.5). If a +2°C offset is applied to this scenario, the ice cap is expected to lose 30-40% of its initial ice volume by 2099. These results provide the first comprehensive evaluation of the impact of vertical ice motion on mass loss derived from geodetic measurements over a large Arctic ice cap. The ice velocity record provides insights into the relationship between surface melt rates and glacier motion over the past 30-60 years. This study projects the mass change of the largest ice cap in the southern Canadian Arctic to 2099, calibrated and validated with a wealth of spatially distributed data for the first time.

This work develops an empirical method for investigation of the flow properties of blood and applies it to a clinically oriented problem. The development focuses on the characterization of the flow properties of a blood sample. According to the theory of continuum mechanics the steady state flow properties of a material are characterized completely by its constitutive (Burchfield, 1972) function which relates the shear stress measured in a rheometer to the shear rate and hematocrit of the sample. Eleven functions derived from various sources were examined for their ability to fit flow data from thirty—one normal individuals, eleven of whom were using oral contraceptives. (The remainder were not using any drugs). A shear rate range of 0.0312 to 124 s⁻¹ was used at hematocrits from 0.29 to 0.55. A non-linear curve fitting procedure allowed an ordering of the functions to be established with respect to their goodness of fit. The function first employed by Walburn and Schneck (1976), T = X₁ exp (X₂ H+X₄ /H²)D[sup 1-X₃] where T = shear stress, D = shear rate, H = hematocrit and X₁ to X₄ are adjustable parameters, was found to be the most successful. This constitutive function was then used to examine data obtained from a population of normal women at various times during the menstrual cycle, as a hemorheological cycle had been reported to occur over this period. The concentrations of several plasma proteins were also determined and plotted over time. No evident cycle of hemorheological properties or protein concentrations was found. / Medicine, Faculty of / Pathology and Laboratory Medicine, Department of / Graduate

Fluidization of biomass particles is an important process in the gasification, pyrolysis and combustion in order to extract energy from biomass. Studies on the fluidization of biomass particles (corn cob and walnut shell), inert particles (sand, glass bead, and alumina), which are added to facilitate fluidization of biomass, and biomass/sand mixture were performed. Experiments were carried out in a 14.5 cm internal diameter cold flow fluidization bed to determine minimum fluidization velocities with air as fluidizing medium. On the of basis of experimental data from both present work and those found in the literature, new correlations were developed to predict minimum fluidization velocity for inert particles as well as biomass particles. It was found that the proposed correlations satisfactorily predict minimum fluidization velocities and was in well agreement with experimental data. Furthermore, effect of weight percentage of biomass in the biomass/sand mixtures was studied. The weight fraction of biomass particles in the mixture was chosen in the range of 0 ~ 100 wt. %. The results show that minimum fluidization velocity of the mixtures increases with an increase in biomass content. Using the present experimental data, a new correlation was developed in terms of mass ratio for predicting values of minimum fluidization velocity of these mixtures. However, the validity of the proposed correlation should be further studied by conducting more experiments using the biomass/sand mixtures of different particle size, shape, and density.

No description available.

The subject of the thesis is to compare layered model and tomographic model. These models are used for description of low velocity layer in seismic survey. The goal of the work was to find out the conditions whether to prefer tomographic model instead of layered model. Program Geostar was used for modelling of low velocity layer. This program is a part of software package produced by CGG Veritas company. Geostar is available at department of Applied Geophysics for study purposes. Four synthetic models were created for comparison of tomographic and layered models. Models of low velocity layer were computed for layered an tomographic model in Geostar environment. Original models were compared to created models. Accuracy was estimated on root mean square error and static correction which was exactly known. In all cases, layered model showed better results then tomographic model. 1

We investigate the influence of rupture complexity on directivity effects. We consider, in particular, how variations in the hypocenter location, the slip distribution and the rupture speed affect the amplitudes of near-field directivity pulses. To that end, we generate a suite of 15 bilateral-rupture models for an Mw 7 event and simulate the corresponding velocity waveforms at a number of sites in the vicinity of the fault. To quantify the influence of the hypocenter location and the rupture speed, we rely on a measure of the isochrone velocity on the fault along a path we term the “closest path”. Our simulations reveal that the peak amplitudes of the directivity pulses largely correlate with the isochrone velocity and that both increase with increasing rupture speed. We also examine the effect of the slip distribution and conclude that the presence of a region of high slip along the “closest path” leads to the amplification of the directivity pulse. Our findings primarily serve to inform empirical ground motion models on the rupture parameters of relevance to directivity.