Este trabalho teve como objetivo avaliar a proteção radiológica em procedimentos fluoroscópicos intervencionistas através de testes de controle de qualidade e levantamento radiométrico, bem como a implementação de um objeto simulador para avaliação da qualidade da imagem e sua otimização, com conseqüente redução da dose no paciente. O objeto simulador, desenvolvido para avaliação de equipamentos de radiologia convencional, mostrou-se eficaz na avaliação da qualidade da imagem em fluoroscopia, bem como na determinação dos níveis de taxa de kerma no ar na entrada da pele de um paciente adulto normal. A avaliação dos parâmetros técnicos dos diversos modos de exposição de um equipamento fluoroscópico digital permitiu estabelecer os indicadores de dose para otimização das imagens em procedimentos intervencionistas. Esta otimização possibilita reduzir a dose no paciente mantendo a qualidade da imagem e, conseqüentemente, sem perda de informação diagnóstica. / This work had as main objective to evaluate the radiological protection in the interventional procedures radiology through quality control and evaluations radiometric, as well as the implementation of a phantom for evaluation of the image quality and the consequent reduction of dose in the patient. The developed simulator object for equipment evaluation of conventional radiology had been revealed efficient in the evaluation of the quality of the fluoroscopic image, as well as in the determination of the entrance surface air kerma rate of the normal adult patient skin. The evaluation of the parameters technician in the diverse ways of exposition of digital fluoroscopy equipment allowed establishing the pointers of improve dose for improve the quality of the images in interventionist procedures. This makes possible to reduce the dose in the patient keeping the quality of the image and, without loss of diagnostic information.

We consider multi-objective simulation optimization (MOSO) problems, that is, nonlinear optimization problems in which multiple simultaneous objective functions can only be observed with stochastic error, e.g., as output from a Monte Carlo simulation model. In this context, the solution to a MOSO problem is the efficient set, which is the set of all feasible decision points for which no other feasible decision<br>point is at least as good on all objectives and strictly better on at least one objective. We are concerned primarily with MOSO problems on integer lattices, that is, MOSO<br><div>problems where the feasible set is a subset of an integer lattice. <br></div><div><br></div><div>In the first study, we propose the Retrospective Partitioned Epsilon-constraint with Relaxed Local Enumeration (R-PεRLE) algorithm to solve the bi-objective simulation optimization problem on integer lattices. R-PεRLE is designed for sampling efficiency. It uses a retrospective approximation (RA) framework to repeatedly call<br></div>the PεRLE sample-path solver at a sequence of increasing sample sizes, using the solution from the previous RA iteration as a warm start for the current RA iteration.<br>The PεRLE sample-path solver is designed to solve the sample-path problem only to within a tolerance commensurate with the sampling error. It comprises a call to<br>each of the Pε and RLE algorithms, in sequence. First, Pε searches for new points to add to the sample-path local efficient set by solving multiple constrained single-<br>objective optimization problems. Pε places constraints to locate new sample-path local efficient points that are a function of the standard error away, in the objective space, from those already obtained. Then, the set of sample-path local efficient points found by Pε is sent to RLE, which is a local crawling algorithm that ensures the set is a sample-path approximate local efficient set. As the number of RA iterations increases, R-PεRLE provably converges to a local efficient set with probability one under appropriate regularity conditions. We also propose a naive, provably-convergent<br>benchmark algorithm for problems with two or more objectives, called R-MinRLE. R-MinRLE is identical to R-PεRLE except that it replaces the Pε algorithm with an<br>algorithm that updates one local minimum on each objective before invoking RLE. R-PεRLE performs favorably relative to R-MinRLE and the current state of the art, MO-COMPASS, in our numerical experiments. Our work points to a family of<br><div>RA algorithms for MOSO on integer lattices that employ RLE for certification of a sample-path approximate local efficient set, and for which the convergence guarantees are provided in this study.</div><div><br></div><div>In the second study, we present the PyMOSO software package for solving multi-objective simulation optimization problems on integer lattices, and for implementing<br></div>and testing new simulation optimization (SO) algorithms. First, for solving MOSO problems on integer lattices, PyMOSO implements R-PεRLE and R-MinRLE, which<br>are developed in the first study. Both algorithms employ pseudo-gradients, are designed for sampling efficiency, and return solutions that, under appropriate regularity<br>conditions, provably converge to a local efficient set with probability one as the simulation budget increases. PyMOSO can interface with existing simulation software and<br>can obtain simulation replications in parallel. Second, for implementing and testing new SO algorithms, PyMOSO includes pseudo-random number stream management,<br>implements algorithm testing with independent pseudo-random number streams run in parallel, and computes the performance of algorithms with user-defined metrics.<br>For convenience, we also include an implementation of R-SPLINE for problems with one objective. The PyMOSO source code is available under a permissive open source<br>license.

<div>New approaches in topology optimization and manufacturing techniques are generating multi-scale, physically realized mechanical components from advanced materials. Current optimization formulations do not consider the dependence of strength on feature size. By failing to account for the mechanical models of this behavior, sub-optimal structures are generated.</div><div><br></div><div>A currently available academic density-based topology optimization code is extended to incorporate strength constraints. A continuum theory of failure novel to the optimization field is implemented to account for both general yielding and fracture dominated failure. The fracture limit is then formulated in terms of well-established models of brittle and quasi-brittle size dependence. Additional models of size dependence based on assumed flaw sizes are considered using the theory of linear elastic fracture mechanics. To unify the optimized topology and the empirical geometric-scaling models used, a novel geometric measure of local size is proposed. This measure interprets the evolving density field using a consistent domain of support and maintains consistency with gradient-based methods of optimization. The geometric measure is evaluated using test-problems which consider a minimum compliance objective under geometric constraints.</div><div><br></div><div>The resulting optimized structures are presented for the geometric and size-dependent strength constrained formulations. The geometrically constrained results illustrate the flexibility and robustness of the proposed local size measure. The various models of size-dependent strength illustrate the impact and necessity of considering physical models of material within the topology optimization formulation. Results which exhibit clear "micro-structural" features and scale transitioning architectures are presented for limited multi-scale optimization studies.</div><div><br></div><div>An attempt at physical validation considering a single model of quasi-brittle material failure is made. Existing approaches for generating 3D volumetric meshes from image data are leveraged to yield CAD interpretations of optimized structures. Structures are then printed using a 3D printing PolyJet process with a previously established size-dependent material. Structures are destructively evaluated under displacement controlled load testing. The resulting tests indicate that the stress states in the structure fail to induce the expected size-dependent material characteristics. Furthermore, the testing results indicate the difficulty in properly accounting for boundary conditions in the topology optimization approach.</div>

This thesis explores the use of computational chemistry to aid in the design of metal-organic frameworks (MOFs) and other materials. A focus is placed on finding exceptional materials to be used for removing CO2 from fossil fuel burning power plants, with other avenues like vehicular methane storage and landfill gas separation being explored as well. These applications are under the umbrella of carbon capture and storage (CCS) which aims to reduce carbon emissions through selective sequestration. We utilize high-throughput screenings, as well as machine learning assisted discovery, to identify ideal candidate materials using a holistic approach instead of relying on conventional gas adsorption properties. The development of ideal materials for CCS requires all aspects of a material to be considered, which can be time-consuming. A large portion of this work has been with high-throughput, or machine learning assisted discovery of ideal candidates for CCS applications. The chapters of this thesis are connected by the goal of finding ideal materials for CCS. They are primarily arranged in increasing complexity of how this research can be done, from using high-throughput screenings with more simple metrics, up to multi-scale machine learning optimization of pressure swing adsorption systems. The work is not presented chronologically, but in a way to tell the best story. Work was done by first applying high-throughput computational screening on a set of experimentally realized MOFs for vehicular methane storage, post-combustion carbon capture, and landfill gas separation. Whenever possible, physically motivated figures of merits were used to give a better ranking and consideration of the materials. From this work, we were able to determine what the realistic limits might be for current MOFs. The work was continued by looking at carbon-based materials (primarily carbon nanoscrolls) for post-combustion carbon capture and vehicular methane storage. The carbon-based materials were found to outperform MOFs; however, further studies are needed to verify the results. Next, we looked at ways to improve the high-throughput screening methodology. One problem area was in the charge calculation, which could lead to unrealistic gas adsorption results. Using the split-charge equilibration method, we developed a robust way to calculate the partial atomic charges that were more accurate than its quick calculation counterparts. This led to gas adsorption properties which more closely mimicked the results determined from time-consuming quantum mechanically derived charges. Simplistic process optimization was then applied to nearly ~3500 experimental structures. To the best of our knowledge, this is the first time that any process optimization has been applied to more than 10s of materials for a study. The process optimization was done by evaluating the desorption at various pressures and choosing the value which gave the lowest energetic cost. It was found that a material synthesized by our collaborators, IISERP-MOF2, was the single best experimentally realized material for post-combustion carbon capture. What made this an interesting result is that by conventional metrics IISERP-MOF2 does not appear to be outstanding. Next, functionalized versions of MOFs were tested in a high-throughput manner, and some of those structures were found to outperform IISERP-MOF2. Although high-throughput computational screenings can be used to determine high-performance materials, it would be impossible to test all functionalized versions of some MOFs, let alone all MOFs. Functionalized MOFs are noteworthy because MOFs are highly tuneable through functionalization and can be made into ideal materials for a given application. We developed a genetic algorithm which, given a base structure and a target parameter, would be able to find the ideal functionalization to optimize the parameter while testing only a small fraction of all structures. In some cases, the CO2 adsorption was found to more than quadruple when functionalized. A better understanding of how materials perform in a PSA system was achieved by performing multi-scale optimizations. Experimentally realized MOFs were tested using atomistic simulations to derive gas adsorption properties. After passing through a few sensible filters, they were then screened using macro-scale pressure swing adsorption simulators, which model how gas separation may occur at a power plant. Using another genetic algorithm, the conditions that the pressure swing adsorption system runs at was optimized for over 200 materials. To the best of our knowledge, this is the highest amount of materials that have had been optimized for process conditions. IISERP-MOF2 was found to perform the best based on many relevant metrics, such as the energetic cost and how much CO2 was captured. It was also found that conventional metrics were unable to be used to predict a material’s pressure swing adsorption performance.

O presente trabalho procura estudar e compreender os processos reativos de chama, tentando identificá-los através de uma abordagem químico termodinâmica, em contraposição às análises clássicas, puramente cinético-químicas. Estas são justificadas por se considerar este tipo de fenômeno como existindo em condições distantes da condição de equilíbrio termodinâmico e não passíveis de análise termodinâmica, coisa que, através desta investigação, pretende-se questionar. Neste estudo, considerou-se a chama como ocorrendo em um escoamento unidimensional ideal, em regime permanente, em fluido perfeito, i.e. não há viscosidade e dividiu-se a chama em fatias, em que a exergia química era transformada em exergia térmica, em se adaptando \"o problema do tijolo aquecido\" (ou \"hot brick problem\"). O processo reativo global de chama adiabática foi, por evidência experimental, considerado como sendo bi-variante i.e. completamente determinado com a definição da pressão e da temperatura dos reagentes, conhecidos a priori, em espécie e em quantidade. O teorema de Duhem1 nos garante, portanto, que caso se estabeleça o equilíbrio, este estaria determinado. Aqui se procurou reunir subsídios para sua identificação. Investigaram-se a modelagem de chamas adiabáticas e reversíveis de duas fatias, consideradas como meio efetivo, em se igualando a exergia química à exergia térmica, bem como o que se considerou como sendo chamas adiabáticas de duas fatias de máxima irreversibilidade interna. Para a chama adiabática irreversível obteve-se temperaturas de ignição próximas à temperatura de autoignição para 4 de 6 combustíveis. Por fim, conclui-se que a chama contínua não é o limite da chama irreversível de infinitas fatias. Enquanto que aquela tem irreversibilidade máxima, segundo o modelo apresentado, a irreversibilidade desta é um máximo relativo. / The present study attempts at an understanding of the reactive processes within a flame. A chemical thermodynamics approach is employed in juxtaposition to the classical analysis which are purely chemical kinetic. These are justified because this phenomenum is considered to take place far from equilibrium conditions and not subject to thermodynamic analysis. This fact will be questioned in this study. A one-dimensional, ideal and steady flow flame was considered. The reactive process of an adiabatic flame was, by experimental evidence, considered to possess two degrees of freedom, i.e it would be completely determined by defining the reactants\' pressure and temperature, whose species and quantities were a priori known. Duhem\'s theorem2 tells us that if equilibrium is estabilished, it would be fully determined. An adiabatic and reversible two-sliced flame (the effective medium) was determined by equating the chemical exergy of the flame to the physical exergy of the two slices relative to the ignition point. Also, the constrained extremum of the difference between the chemical and physical exergies allowed the relative maximum of an internally irreversible adiabatic flame to be determined. For the irreversible flame, close simulation of the autoignition temperature for 4 of 6 fuels was obtained. Finally, the conclusion that a continuous flame is not the limit of an irreversible flame with infinite slices is demonstrated. Whilst that flame is the flame with maximum irreversibility, this flame has a relative maximum of internal irreversibility.

Segundo a definição original de MCINERNEY & TERZOPOULOS (1995), modelos deformáveis são curvas ou superfícies formadas por pontos conectados que simulam corpos elásticos. Por superarem muitas limitações associadas ao procedimento manual e às técnicas tradicionais de processamento, os contornos deformáveis têm se popularizado. Ainda que o uso dos contornos deformáveis seja vasto e crescente, aspectos relevantes da teoria ainda têm demandado atenção. Muitas referências têm sido feitas às limitações da técnica impostas sobretudo pelo seu processo evolutivo. A convergência a mínimos locais e o agrupamento indesejado de pontos, por exemplo, limitam o emprego da técnica em cenários ruidosos e complexos como os encontrados em reservatórios de petróleo. Esse trabalho apresenta uma abordagem inédita às limitações dos contornos deformáveis. Pela definição de um segundo problema de minimização são definidas distâncias ótimas dos pontos do contorno deformável segundo critério de optimalidade que contempla as particularidades do contorno buscado. Os resultados demonstram que a técnica proposta é provedora de maior enquadramento entre o contorno buscado e o identificado, define solução definitiva aos problemas do agrupamento e espalhamento indesejados de pontos, aumenta a efetividade dos contornos deformáveis em regiões côncavas e, em acréscimo, define metodologia unicamente capaz de dotar os contornos deformáveis de sensibilidade quanto às particularidades de contorno. / According to the original definition of Terzopoulos, deformable models are curves or surfaces formed by connected points that simulate elastic bodies. By overcoming many limitations associated with the manual procedure and the traditional techniques of processing, deformable contours have become popular. Although the use of deformable contours is vast and growing aspects of the theory still demand attention. Many references have been made to the limitations of the technique imposed by the process evolution process. The convergence to minimum and unwanted bundling points, for example, limit the use of the technic on noisy and complex scenarios as those found in oil reservoirs. This work presents a novel approach to the limitations of deformable contours. By the definition of a second problem of minimization are defined optimal distances of the points of deformable contour according to a optimality criterion that incorporates features of the contour sought. The results show that the proposed technique peovides a larger framework between the contour sought and identified, defines a permanent solution to the problems of grouping and unwanted scattering of points, increases the effectiveness of deformable contours in concave regions and, in addition, defines methodology only able to provide the contours deformable sensitivity about the peculiarities of the contour.

Neste trabalho apresentamos o método de amostragem intencional via otimização. Tal método baseia-se na fundamentação de que devemos controlar a seleção amostral sempre que houver conhecimento suficiente para garantir boas inferências de quantidades conhecidas e de alguma forma correlacionadas com aquelas desconhecidas e de interesse. Para a resolução dos problemas de otimização foram utilizadas técnicas de programação linear. Três aplicações foram apresentadas e em todas elas notou-se que o procedimento de amostragem intencional produziu amostras com bom balanceamento entre as composições amostrais e de referência. / In this work we present the method of intentional sampling by optimization. Such method is based on the fact that we must control the sampling selection whenever we have enough knowledge to guarantee good inferences of known quantities and somehow correlated with those interesting and unknown ones. Linear programming techniques were used to solve the optimization problems. Three applications were presented and all of them produced samples with good balancing properties related to the referenced populations.

Com a liberação do uso da energia nuclear para aplicações pacíficas, a Comissão Internacional de Proteção Radiológica, CIPR, fundada em 1928, criou em 1958 um sistema de proteção às doses de radiação ionizante indesejáveis causadas aos trabalhadores, indivíduos de público e meio-ambiente para viabilizar a introdução dessas aplicações. Esse sistema de proteção é adotado pelo Organismo Internacional de Energia Atômica, OIEA, que publica recomendações em séries de segurança, SS e pela Comissão Nacional de Energia Nuclear, CNEN, que publica regulamentações em normas. Essas recomendações internacionais e regulamentações nacionais passaram por adaptações e necessitam ser aplicadas dessa forma. O presente trabalho utiliza recomendações da publicação 75 da CIPR, da publicação 115 da SS e regulamentações da norma NN 3.01 da CNEN para apresentar, através de medidas de radioproteção, o controle das doses de radiação ionizante para trabalhadores em uma instalação radiativa que trabalha com pesquisa, produção, fracionamento e embalagem de fontes não-seladas para uso clínico. Dessa forma, é possível prevenir adequadamente as doses indesejáveis e confirmar as doses recebidas. / With the liberation of the use of the nuclear energy for peaceful applications, International Commission Radiological Protection, ICRP, founded in 1928, created a system of protection of the undesirable doses of ionizing radiation in 1958. This has been received by workers, members of the public and environment and hence it became possible for the introduction of these applications. This protection system is adopted by the International Agency of Energy Atomic, IAEA, that publishes recommendations in safety series, SS and by the Comissão Nacional de Energia Nuclear, CNEN, which publishes these regulations. The international recommendations and national regulations were adapted and they need to be applied in this way. The present paper uses recommendations of the publication 75 from ICRP, of the publication 115 from SS and regulations of the regulation NN 3.01 from CNEN to present, through radiological protection measures, the ionizing radiation dose control for workers in a nuclear plant that works in the research, production, division and packing of unsealed sources to be used in clinical applications. In that way it is possible to prevent appropriately the undesirable doses and to confirm the received doses.

by Lau Wai-tong. / Bibliography: leaves 45-47 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1985

by Wong Kam Chau. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1990. / Bibliography: leaves 114-121. / Introduction: --- p.1 / Outline of the thesis: --- p.9 / Part I: / List of notations: --- p.12 / Chapter Chapter I: --- Basic model --- p.16 / Chapter Chapter II： --- Self-interested team --- p.21 / Chapter Chapter III --- Altruistic team --- p.33 / Chapter Chapter IV: --- Sub-contracting and supervisory system --- p.45 / Chapter Chapter V: --- Team with leader --- p.55 / Chapter Chapter VI: --- Conclusion of part I --- p.59 / Appendix: --- p.61 / Part II: / Chapter Chapter VII --- The existence theorem of optimal information system of one agent --- p.82 / Chapter Chapter VIII: --- Extension to a team --- p.104 / Reference: --- p.114