Дисертації з теми "Dry method"

Dry powder inhalers (DPI) are a common asthma treatment. Despite the number of commercial devices available, little is known about their internal operation: the process of fluidising a powder dose into an inhalation airflow. This PhD aims to investigate this process, and demonstrate that it can be modelled computationally. . Experimental work is described to record high speed video of the dose fluidisation from simplified DPls. Typical DPI powders such as lactose are tested, along with cohesionless glass spheres and aluminium flakes. Two distinct dose fluidisation mechanisms are identified, labelled 'fracture' and 'erosion'. Lactose exhibits a fracture mechanism -- large agglomerates are produced as the powder bed cracks along lines of weakness. Glass or aluminium particles exhibit an erosion mechanism: powder is entrained into the flow as individual particles from the bed surface. The recorded video is quantitatively analysed to determine fluidisation timescales and pressures. Shear cell test results show that predicting the mechanism of fluidisation is not possible using averaged bulk powder properties. This suggests any DPI model must include the fundamental particle interactions. The discrete element method (OEM) is introduced as a computational technique capable of predicting DPI behaviour from individual particle properties. The numerical accuracy of the method is assessed, showing that time integration is limited to a maximum of 2nd order accuracy due to discontinuities in particle contact forces. A sensitivity analysis shows inter-particle cohesion is the dominant factor affecting OEM predictions. OEM is used to create a simple model of the dose fluidisation that occurs within a DPI. The results are compared with real powder behaviour. OEM is shown to capture the realistic fluidisation of both lactose and glass powder doses. It is concluded that OEM is a promising technique to predict DPI behaviour, although further work is required to quantify inter--particle cohesive parameters

Thesis (Ph. D.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on November 26, 2007 Vita. Includes bibliographical references.

In this work, a two-phase lattice Boltzmann method (LBM) approach is implemented to investigate the hydrodynamic behavior of a single droplet impingement on a dry surface. LBM is a recently developed powerful technique to compute a wide range of fluid flow problems, especially in applications involving interfacial dynamics and complex geometries. Instead of solving the non-linear Navier-Stokes equations, which are complicated partial differential equations, LBM solves a set of discretized linear equations, which are easy to implement and parallelize. The fundamental idea of LBM is to recover the macroscopic properties of the fluid which obeys Navier-Stokes equations, by using simplified kinetic equations that incorporate the essential physics at the microscopic level. Considering the numerical instability induced by large density difference between two phases during the LBM simulations, the particular LBM scheme used in this study has its benefits when dealing with high density ratios. All the simulations are conducted for density ratio up to 50 in a three-dimensional Cartesian coordinate system, and three important dimensionless numbers, namely Weber number, Reynolds number and Ohnesorge number, are used for this study. To validate this multiphase LBM approach, several benchmark tests are conducted. First, the angular frequency of an oscillating droplet is calculated and compared with the corresponding theoretical value. Errors are found to be within 6.1% for all the cases. Secondly, simulations of binary droplet collisions are conducted in the range of 20M.S.M.E.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Mechanical Engineering MSME

Aerospace structural components made from polymer matrix composites (PMCs) offer numerous advantages. Their high stiffness and high strength combined with low densities enable lower fuel consumption coupled with higher payloads. As a result, PMCs provide an important economic advantage over typical metallic airframes. Textile reinforcements for PMCs are made by assembling reinforcement fibres, typically carbon. Then, the textile reinforcements are typically cut into smaller pieces, stacked, draped and assembled into a dry assembly called a preform, the shape of which generally approaches that of the PMC part to be made. This manufacturing process is labour intensive and expensive. Novel thick, net-shape, drapable, high vf textile reinforcements used toward manufacturing aerospace PMCs are being developed at the University of Ottawa. The technology enables the manufacturing of flat, drapable multilayered near net-shape preforms. The bending and in-plane shear behaviours of such novel thick reinforcement textiles was investigated to understand and define the behaviour of such thick fabric reinforcements when formed into required shapes. A bending apparatus was developed for investigating the bending behaviour of these novel thick reinforcement fabrics and an articulated frame shear rig was used for investigating the in-plane shear behaviour. A non-destructive inspection method using infrared imaging was used for investigating and identifying flaws and defects in these thick, dry textile reinforcements, aiming at increasing the quality and reproducibility of the final PMC parts made from these reinforcements.

[EN] The main topic of the present thesis is the improvement of fabrication processes simulation by means of the Level Set (LS) method. The LS is a mathematical approach used for evolving fronts according to a motion defined by certain laws. The main advantage of this method is that the front is embedded inside a higher dimensional function such that updating this function instead of directly the front itself enables a trivial handling of complex situations like the splitting or coalescing of multiple fronts. In particular, this document is focused on wet and dry etching processes, which are widely used in the micromachining process of Micro-Electro-Mechanical Systems (MEMS). A MEMS is a system formed by mechanical elements, sensors, actuators, and electronics. These devices have gained a lot of popularity in last decades and are employed in several industry fields such as automotive security, motion sensors, and smartphones. Wet etching process consists in removing selectively substrate material (e.g. silicon or quartz) with a liquid solution in order to form a certain structure. This is a complex process since the result of a particular experiment depends on many factors, such as crystallographic structure of the material, etchant solution or its temperature. Similarly, dry etching processes are used for removing substrate material, however, gaseous substances are employed in the etching stage. In both cases, the usage of a simulator capable of predicting accurately the result of a certain experiment would imply a significant reduction of design time and costs. There exist a few LS-based wet etching simulators but they have many limitations and they have never been validated with real experiments. On the other hand, atomistic models are currently considered the most advanced simulators. Nevertheless, atomistic simulators present some drawbacks like the requirement of a prior calibration process in order to use the experimental data. Additionally, a lot of effort must be invested to create an atomistic model for simulating the etching process of substrate materials with different atomistic structures. Furthermore, the final result is always formed by unconnected atoms, which makes difficult a proper visualization and understanding of complex structures, thus, usually an additional visualization technique must be employed. For its part, dry etching simulators usually employ an explicit representation technique to evolve the surface being etched according to etching models. This strategy can produce unrealistic results, specially in complex situations like the interaction of multiple surfaces. Despite some models that use implicit representation have been published, they have never been directly compared with real experiments and computational performance of the implementations have not been properly analysed. The commented limitations are addressed in the various chapters of the present thesis, producing the following contributions: - An efficient LS implementation in order to improve the visual representation of atomistic wet etching simulators. This implementation produces continuous surfaces from atomistic results. - Definition of a new LS-based model which can directly use experimental data of many etchant solutions (such as KOH, TMAH, NH4HF2, and IPA and Triton additives) to simulate wet etching processes of various substrate materials (e.g. silicon and quartz). - Validation of the developed wet etching simulator by comparing it to experimental and atomistic simulator results. - Implementation of a LS-based tool which evolves the surface being etched according to dry etching models in order to enable the simulation of complex processes. This implementation is also validated experimentally. - Acceleration of the developed wet and dry etching simulators by using Graphics Processing Units (GPUs).
[ES] El tema principal de la presente tesis consiste en mejorar la simulación de los procesos de fabricación utilizando el método Level Set (LS). El LS es una técnica matemática utilizada para la evolución de frentes según un movimiento definido por unas leyes. La principal ventaja de este método es que el frente está embebido dentro de una función definida en una dimensión superior. Actualizar dicha función en lugar del propio frente permite tratar de forma trivial situaciones complejas como la separación o la colisión de diversos frentes. En concreto, este documento se centra en los procesos de atacado húmedo y seco, los cuales son ampliamente utilizados en el proceso de fabricación de Sistemas Micro-Electro-Mecánicos (MEMS, de sus siglas en inglés). Un MEMS es un sistema formado por elementos mecánicos, sensores, actuadores y electrónica. Estos dispositivos hoy en día son utilizados en muchos campos de la industria como la seguridad automovilística, sensores de movimiento y teléfonos inteligentes. El proceso de atacado húmedo consiste en eliminar de forma selectiva el material del sustrato (por ejemplo, silicio o cuarzo) con una solución líquida con el fin de formar una estructura específica. Éste es un proceso complejo pues el resultado depende de muchos factores, tales como la estructura cristalográfica del material, la solución atacante o su temperatura. De forma similar, los procesos de atacado seco son utilizados para eliminar el material del sustrato, sin embargo, se utilizan sustancias gaseosas en la fase de atacado. En ambos casos, la utilización de un simulador capaz de predecir de forma precisa el resultado de un experimento concreto implicaría una reducción significativa del tiempo de diseño y de los costes. Existen unos pocos simuladores del proceso de atacado húmedo basados en el método LS, no obstante tienen muchas limitaciones y nunca han sido validados con experimentos reales. Por otro lado, los simuladores atomísticos son hoy en día considerados los simuladores más avanzados pero tienen algunos inconvenientes como la necesidad de un proceso de calibración previo para poder utilizar los datos experimentales. Además, debe invertirse mucho esfuerzo para crear un modelo atomístico para la simulación de materiales de sustrato con distintas estructuras atomísticas. Asimismo, el resultado final siempre está formado por átomos inconexos que dificultan una correcta visualización y un correcto entendimiento de aquellas estructuras complejas, por tanto, normalmente debe emplearse una técnica adicional para la visualización de dichos resultados. Por su parte, los simuladores del proceso de atacado seco normalmente utilizan técnicas de representación explícita para evolucionar, según los modelos de atacado, la superficie que está siendo atacada. Esta técnica puede producir resultados poco realistas, sobre todo en situaciones complejas como la interacción de múltiples superficies. A pesar de que unos pocos modelos son capaces de solventar estos problemas, nunca han sido comparados con experimentos reales ni el rendimiento computacional de las correspondientes implementaciones ha sido adecuadamente analizado. Las expuestas limitaciones son abordadas en la presente tesis y se han producido las siguientes contribuciones: - Implementación eficiente del método LS para mejorar la representación visual de los simuladores atomísticos del proceso de atacado húmedo. - Definición de un nuevo modelo basado en el LS que pueda usar directamente los datos experimentales de muchos atacantes para simular el proceso de atacado húmedo de diversos materiales de sustrato. - Validación del simulador comparándolo con resultados experimentales y con los de simuladores atomísticos. - Implementación de una herramienta basada en el método LS que evolucione la superficie que está siendo atacada según los modelos de atacado seco para habilitar la simulación de procesos comple
[CAT] El tema principal de la present tesi consisteix en millorar la simulació de processos de fabricació mitjançant el mètode Level Set (LS). El LS és una tècnica matemàtica utilitzada per a l'evolució de fronts segons un moviment definit per unes lleis en concret. El principal avantatge d'aquest mètode és que el front està embegut dins d'una funció definida en una dimensió superior. D'aquesta forma, actualitzar la dita funció en lloc del propi front, permet tractar de forma trivial situacions complexes com la separació o la col·lisió de diversos fronts. En concret, aquest document es centra en els processos d'atacat humit i sec, els quals són àmpliament utilitzats en el procés de fabricació de Sistemes Micro-Electro-Mecànics (MEMS, de les sigles en anglès). Un MEMS és un sistema format per elements mecànics, sensors, actuadors i electrònica. Aquests dispositius han guanyat molta popularitat en les últimes dècades i són utilitzats en molts camps de la indústria, com la seguretat automobilística, sensors de moviment i telèfons intel·ligents. El procés d'atacat humit consisteix en eliminar de forma selectiva el material del substrat (per exemple, silici o quars) amb una solució líquida, amb la finalitat de formar una estructura específica. Aquest és un procés complex ja que el resultat de un determinat experiment depèn de molts factors, com l'estructura cristal·logràfica del material, la solució atacant o la seva temperatura. De manera similar, els processos d'atacat sec son utilitzats per a eliminar el material del substrat, no obstant, s'utilitzen substàncies gasoses en la fase d'atacat. En ambdós casos, la utilització d'un simulador capaç de predir de forma precisa el resultat d'un experiment en concret implicaria una reducció significativa del temps de disseny i dels costos. Existeixen uns pocs simuladors del procés d'atacat humit basats en el mètode LS, no obstant tenen moltes limitacions i mai han sigut validats amb experiments reals. Per la seva part, els simuladors atomístics tenen alguns inconvenients com la necessitat d'un procés de calibratge previ per a poder utilitzar les dades experimentals. A més, deu invertir-se molt d'esforç per crear un model atomístic per a la simulació de materials de substrat amb diferents estructures atomístiques. Així mateix, el resultat final sempre està format per àtoms inconnexos que dificulten una correcta visualització i un correcte enteniment d'aquelles estructures complexes, per tant, normalment deu emprar-se una tècnica addicional per a la visualització d'aquests resultats. D'altra banda, els simuladors del procés d'atacat sec normalment utilitzen tècniques de representació explícita per evolucionar, segons els models d'atacat, la superfície que està sent atacada. Aquesta tècnica pot introduir resultats poc realistes, sobretot en situacions complexes com per exemple la interacció de múltiples superfícies. A pesar que uns pocs models son capaços de resoldre aquests problemes, mai han sigut comparats amb experiments reals ni tampoc el rendiment computacional de les corresponents implementacions ha sigut adequadament analitzat. Les exposades limitacions son abordades en els diferents capítols de la present tesi i s'han produït les següents contribucions: - Implementació eficient del mètode LS per millorar la representació visual dels simuladors atomístics del procés d'atacat humit. - Definició d'un nou model basat en el mètode LS que puga utilitzar directament les dades experimentals de molts atacants per a simular el procés d'atacat humit de diversos materials de substrat. - Validació del simulador d'atacat humit desenvolupat comparant-lo amb resultats experimentals i amb els de simuladors atomístics. - Implementació d'una ferramenta basada en el mètode LS que evolucione la superfície que està sent atacada segons els models d'atacat sec per, d'aquesta forma, habilitar la simulació de processo
Montoliu Álvaro, C. (2015). Study, Modelling and Implementation of the Level Set Method Used in Micromachining Processes [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/58609
TESIS

A time-discrete formulation of the variational principle of mechanics is used to provide a consistent theoretical framework for the construction and analysis of low order integration methods. These are applied to mechanical systems subject to mixed constraints and dry frictional contacts and impacts---machines. The framework includes physics motivated constraint regularization and stabilization schemes. This is done by adding potential energy and Rayleigh dissipation terms in the Lagrangian formulation used throughout. These terms explicitly depend on the value of the Lagrange multipliers enforcing constraints. Having finite energy, the multipliers are thus massless ghost particles. The main numerical stepping method produced with the framework is called SPOOK.

Variational integrators preserve physical invariants globally, exactly in some cases, approximately but within fixed global bounds for others. This allows to product realistic physical trajectories even with the low order methods. These are needed in the solution of nonsmooth problems such as dry frictional contacts and in addition, they are computationally inexpensive. The combination of strong stability, low order, and the global preservation of invariants allows for large integration time steps, but without loosing accuracy on the important and visible physical quantities. SPOOK is thus well-suited for interactive simulations, such as those commonly used in virtual environment applications, because it is fast, stable, and faithful to the physics.

New results include a stable discretization of highly oscillatory terms of constraint regularization; a linearly stable constraint stabilization scheme based on ghost potential and Rayleigh dissipation terms; a single-step, strictly dissipative, approximate impact model; a quasi-linear complementarity formulation of dry friction that is isotropic and solvable for any nonnegative value of friction coefficients; an analysis of a splitting scheme to solve frictional contact complementarity problems; a stable, quaternion-based rigid body stepping scheme and a stable linear approximation thereof. SPOOK includes all these elements. It is linearly implicit and linearly stable, it requires the solution of either one linear system of equations of one mixed linear complementarity problem per regular time step, and two of the same when an impact condition is detected. The changes in energy caused by constraints, impacts, and dry friction, are all shown to be strictly dissipative in comparison with the free system. Since all regularization and stabilization parameters are introduced in the physics, they map directly onto physical properties and thus allow modeling of a variety of phenomena, such as constraint compliance, for instance.

Tutorial material is included for continuous and discrete-time analytic mechanics, quaternion algebra, complementarity problems, rigid body dynamics, constraint kinematics, and special topics in numerical linear algebra needed in the solution of the stepping equations of SPOOK.

The qualitative and quantitative aspects of SPOOK are demonstrated by comparison with a variety of standard techniques on well known test cases which are analyzed in details. SPOOK compares favorably for all these examples. In particular, it handles ill-posed and degenerate problems seamlessly and systematically. An implementation suitable for large scale performance and accuracy testing is left for future work.

Mestrado em Engenharia Mecânica
In the present document, a new explicit FEM-based software developed to optimize tyre pattern geometry is presented. The new software calculates forces and displacements in tyre tread components after applying a load and a longitudinal shear displacement. To overcome long meshing and calculation times, simplifications are made. In this work, the usability of the simplifications is checked and the new software is adjusted and validated through the use of other FEM-based software in the market (Abaqus). To perform the validation, models are created, reproducing tyre tread blocks with different geometries, and the same simulation is reproduced in Abaqus. A set of simulations is run in both software. The results of the simulations are compared regarding the final shape, reaction forces and displacements in the nodes of the models. Finally, simple friction formulations are proposed and implemented in the new software, as well as a slip parameter and a water height level in the tyre footprint, in order to simulate braking performance in dry and wet surfaces. The results are then compared with experimental tests.
No presente documento, um novo software baseado no Método dos Elementos Finitos (MEF) explícito, desenvolvido para otimizar a geometria do padrão de pneus é apresentado. O novo software calcula forças e deslocamentos em componentes do piso dos pneus após a aplicação de uma carga e um deslocamento longitudinal. Para superar longos tempos de geração de malha e de cálculo, simplificações são feitas. Neste trabalho, a viabilidade para a utilização das simplificações é verificada e o novo software é ajustado e validado através da utilização de outro software baseado no MEF no mercado (Abaqus). Para executar a validação, modelos são criados, reproduzindo blocos do piso do pneu com diferentes geometrias, e a mesma simulação é reproduzida no Abaqus. Um conjunto de simulações é executado em ambos os softwares. Os resultados das simulações são comparados em relação à forma final, às forças de reação e deslocamentos nos nós dos modelos. Finalmente, simples formulações de fricção são propostas e implementadas no novo software, bem como um parametro de deslizamento e nível da altura da camada de água na pegada do pneu, a fim de simular o desempenho de travagem em piso seco e molhado. Os resultados são, então, comparados com testes experimentais.

Master of Science
Department of Animal Sciences and Industry
James S. Drouillard
A series of five trials were conducted to evaluate grain processing, distiller's grains inclusion in finishing diets, interactions between distiller's grains and dry-rolled corn (DRC) or steam-flaked corn (SFC), efficacy of removing roughage in the presence of distiller's grains and the digestibility of distiller's grains in steam-flaked and dry-rolled corn diets. The first trial was designed to determine the optimum flake density of SFC in beef finishing diets. Diets consisted of corn flaked to densities of 360, 411, or 462 g/L. Observed improvements in mill production would support increasing flake density; however numerical decreases in animal performance offset economic benefits of increased productivity. The second trial was conducted to evaluate optimum levels of sorghum wet distiller's grains in finishing diets. Crossbred yearling steers were fed diets containing DRC or SFC and levels of distiller's grains were 0, 10, 20, or 30% of diet dry matter. Distiller's grains can effectively replaced a portion of the corn in finishing diets, but their nutritional value was greater in DRC diets than in SFC diets. In trial 3, crossbred heifers were fed diets containing SFC with 0% DDG and 15% corn silage (CS), 25% DDG and 15% CS, or 25% DDG and 5% CS. In trial 4, crossbreed heifers were fed diets similar containing DRC or SFC with 0% DDG and 15% CS, 25% DDG and 15% CS, or 25% DDG and 5% CS. Results indicate that roughage levels can be reduced in feedlot diets containing DDG with no adverse effects on performance or carcass quality. The fifth trial was a metabolism study conducted to evaluate the digestibility of DDG in beef cattle. Treatments consisted of DRC with 0% DDG, DRC with 25% DDG, SFC with 0% DDG, and SFC with 25% DDG. There were no significant grain processing by distiller's grain interactions observed in main effects. In conclusion optimum flake density was 360 g/L, feeding distiller's grains has a greater value in DRC diets vs. SFC diets, roughage level and type are important in formulating finishing diets, roughage can be reduced when feeding distiller's grains, and ruminal ammonia, and pH are decreased and ruminal lactate is increased when feeding DDG and SFC.

This thesis contributes to a development of a method for rheological characterization of microfibrillated cellulose. The intended use of the method is to be able to distinguish between different grades of microfibrillated cellulose. The method that was developed had preparation procedure of suspensions, pH, dry content and conductivity as well as measuring geometry and measuring sequence in mind. The method resulted in using a propeller mixer for sample preparation and the most suitable properties of the samples for comparison of different qualities of microfibrillated cellulose was evaluated to be pH 8 with a dry content of 2.0 wt% and a conductivity of 110 µS/cm. The rheology of the microfibrillated cellulose suspensions was examined by using a dynamic rotational rheometer and a splined bob and cup (C25G/PC25G). The complex viscosity from amplitude sweeps is used as the parameter to distinguish between different grades of 2 wt% microfibrillated cellulose suspensions. At 1.0 wt% the pH of the suspensions appeared to have a very small impact on the results from rheological measurements while an increased conductivity of the suspensions resulted in an increased complex viscosity. The dry content dependency appeared to be exponential in the range of 0.5 to 3.0 wt% and it was thus easier to distinguish between different grades of microfibrillated cellulose when the dry content is 2.0 wt% compared to 1.0 or 1.5 wt%.

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CAPES
PROPESQ- UFPE
Os acidentes de trânsito tem se apresentado como um sério problema de saúde no mundo, ocasionando prejuízos físicos, emocionais e econômicos. Esses tipos de acidentes são diretamente influenciados por ações individuais dos motoristas e de outros usuários. Leis ou medidas que afetem os incentivos individuais na forma de se comportarem no trânsito podem levar a mudanças nas taxas de mortalidade, entre elas as que restringem a associação, consumo de bebidas alcoólicas e direção, como a Lei Seca implantada no Brasil no ano de 2008. Desta forma, o objetivo desta dissertação é avaliar o impacto da Lei Seca sobre a mortalidade por acidente de trânsito automotivo na Região Metropolitana de Recife, Pernambuco. Para tanto, a partir do método do Controle Sintético de dados de mortalidade obtidos no DATASUS estimou-se um efeito positivo da referida lei na RMR, resultando em uma redução da taxa de mortalidade por acidentes de trânsito automotivo em média de um ponto, equivalente a 45%, entre os anos de 2008 a 2013. Ou seja, a Lei Seca apresentou como uma medida eficiente na prevenção de mortes no trânsito decorrentes de acidentes automobilísticos na região em estudo.
Traffic accidents must be presented as a serious health problem in the world, causing damages to physical, emotional and economic. These types of accidents are directly influenced by individual actions of drivers and of other users. Laws or measures that affect individual incentives in the form of behave in transit may lead to changes in mortality rates, among them the that restrict the association, consumption of alcoholic beverages and direction, as the Dry Law implanted in Brazil in the year 2008. In this way, the objective of this dissertation is to assess the impact of the Dry Law on mortality by automotive traffic accident in the Metropolitan Region of Recife, Pernambuco. For both, from the method of synthetic control of mortality data obtained in DATASUS we estimated a positive effect of this law in the metropolitan Recife, resulting in a reduction in the rate of mortality from traffic accidents automotive on average a point, equivalent to 45%, between the years of 2008 to 2013. Thus the Dry Law presented as an efficient in the prevention of traffic related deaths resulting from car accidents in the region under study.

Метою магістерської дисертації є удосконалення конструкції корпусу обертової печі шляхом збільшення теплового опору футерівки. Об’єктом дослідження є піч обертова 4x60 при виробництві цементу «сухим» способом. Предмет дослідження встановлення додаткової теплоізоляції в футерівку печі для зменшення втрат тепла в навколишнє середовище. У магістерській дисертації зроблений вибір та обґрунтування модернізації обертової печі, що зменшує втрати тепла за рахунок чого можливо зменшити витрати палива та збільшити продуктивність печі. Теоретичні ідеї модернізації підтверджуються результатами розрахунку, які виконуються за допомогою сучасних систем САПР системи ANSIS. Отримані дані підтверджують працездатність модернізованої печі, так як отримані максимальні напруження не перевищують допустимих і дають можливість суттєво зменшити втрати тепла через корпус, що позитивно вплине на технологічний процес. В пояснювальній записці в достатньому обсязі представлені розрахунки обертової печі, проведено автоматизацію виробничого процесу, розглянуті основні вимоги до техніки безпеки та навколишнього середовища при роботі з машиною.
The aim of the master's thesis is to improve the design of the rotary kiln body by increasing the thermal resistance of the lining. The object of the study is a 4x60 rotary kiln in dry cement production. The subject of the study is the installation of additional thermal insulation in the furnace lining to reduce heat losses to the environment. In the master's thesis the choice and justification of the modernization of the rotary kiln is made, which reduces the heat loss due to which it is possible to reduce fuel consumption and increase the kiln productivity. The theoretical ideas of modernization are confirmed by the results of the calculation, which are performed using modern ANSIS CAD systems. The obtained data confirm the efficiency of the modernized furnace, since the maximum stresses obtained do not exceed the allowable and allow to significantly reduce heat losses through the housing, which will positively affect the technological process. The explanatory note sufficiently presents calculations of the rotary kiln, automation of the production process, the main requirements for safety and the environment when operating the machine.

Particles exist in great abundance in nature, such as in sands and clays, and they also constitute 75% of the materials used in industry (e.g., mineral ores, formulated pharmaceuticals, dyes, detergent powders). When a load is applied to a bulk assembly of soil particles, the response of a geomaterial at the bulk (macro) scale, originates from the changes that take place at the particle scale. If particle breakage occurs, the shape and size of the particles comprising the bulk are changed; this induces changes in the contact network through which applied loads are transmitted. As a result, changes at the micro-scale can significantly affect the mechanical behaviour of a geomaterial at a macro-scale. It is therefore unsurprising that the mechanisms leading to particle breakage are a subject of intense research interest in several fields, including geomechanics. In this thesis, particle breakage of two dry granular materials is studied, both experimentally and numerically. The response of the materials is investigated under different stress paths and in all the tests grain breakage occurs. High resolution x-ray computed micro-tomography (XCT) is used to obtain 3D images of entire specimens during high confinement triaxial compression tests and strain controlled oedometric compression tests. The acquired images are processed and measurements are made of the temporal and spatial evolution of breakage, local variations of porosity, volumetric and shear strain and grading. The evolution and spatial distribution of quantified breakage including the resulting particle size distribution for the whole specimen and for specific areas, are presented and further related to the localised shear and volumetric strains that developed in the specimens. In addition, the discrete element method (DEM) was used to provide further micro-mechanical insight of the underlying mechanisms leading to particle breakage. Classical DEM simulations, using a Hertz-Mindlin contact model and non-breakable spheres, was first deployed to study the initiation and likelihood of particle breakage under oedometric compression. Moreover, a bonded DEM model was used to create clumps that represent each particle and simulate breakage of particles under single particle compression. The DEM model parameters were obtained from results of single particle compression test and the models were validated against the quantitative 3D information of the micro-scale, acquired from the XCT analysis.

Déterminer la durée de vie d'une pièce sous excitation vibratoire est l'un des enjeux majeurs dans l'ingénierie mécanique. Afin de donner une estimation fiable de la durée de vie, un calcul correct de champ de contrainte, qui est fortement lié à la forme et l'amplitude modale est obligatoire. Cependant, le calcul de réponse d'une structure assemblée est difficile, surtout avec la présence de frottement sec aux interfaces de liaisons qui entraîne un amortissement non linéaire. La recherche de la thèse commence par une identification phénoménologique de l'amortissement induit par le frottement sec avec 3 modèles analytiques, notamment la plaque sandwich, la rotule frottante et la plaque von Kármán. Après la caractérisation de l'amortissement structural au 1er et 2ème ordre, les influences des paramètres comme la pression de serrage, le rapport d'épaisseurs ainsi que le nombre de soudures sont analysés. La deuxième partie des travaux traite les problèmes d'amortissement avec une géométrie de dimension finie. La plaque de von Kármán est reprise dans l'étude et une méthode hybride de différences finies et d'éléments finis est adopté pour résoudre le couplage entre la flexion et les efforts internes. Une attention particulière est portée à la notion de modes non linéaires dans le cas de la plaque von Kármán. Les conditions nécessitant l'introduction de modes non linéaires sont identifiées. Le champ de force fictif qui est proposé dans l'étude sur la plaque von Kármán est ensuite introduit dans le cas de la plaque sandwich. Puis la propagation de glissement et l'influence de champ fictif sont étudiées. Afin de vérifier les phénomènes trouvés dans les études théoriques, une installation expérimentale est conçue et montée pour l'amortissement structural au premier ordre. Dans la dernière partie qui est basée sur les observations faites dans les études précédentes, une méthode de calcul de l'amortissement dans un environnement industriel est proposée. Cette méthode permet de donner un amortissement pour chaque mode isolé
The determination of a component's lifetime under vibrational excitation is one of the most difficult challenges in mechanical engineering. In order to provide a reliable estimation of lifetime, a correct calculation of stress field, which depends on the modal form and its amplitude, is needed. However, the vibrational response calculation on an assembled structure is not easy, especially with the nonlinear structural damping induced by frictional contact surface. The research in the current thesis starts from the phenomenological identification of damping with the help of 3 analytical models, in particular the sandwich plate, rotational joint and von Karman plate. Structural damping of 1st and 2nd order are identified. The influence of parameters like clamping pressure, thickness ratio and number of welding points are also analyzed. The second part of the research focuses on problems with finite dimensions. The von Karman plate serves as the subject of the study and a hydride method which combines FDM and FEM is proposed to solve the coupling between defection and in-plane force field. A special attention is paid to nonlinear mode theory, the conditions under which the nonlinear mode is necessary are identified. The fictive force field proposed in the study of von Kármán plate is then applied to the sandwich plate model. The slipping's propagation as well as the influence of fictive force field are studied. To verify the existence of the found phenomena in the previous studies, an experimental setup is designed and mounted for the 1st order structural damping. In the last part of the research, which is based on the observations previously obtained from academic models, a calculation method of friction-induced damping in structures with complex geometries is proposed for the application in the industrial environment. This methods enables the estimation of damping for each isolated mode

Mestrado MEDFOR - Mediterranean Forestry and Natural Resources Management / Instituto Superior de Agronomia
Extraction of cork from montados or cork oak forests is one of the main activities in Portugal. 23% of Portuguese forests are from Quercus suber and Portugal is the main producer of cork in the world. Commonly, every 9 years, but also 10 or more, the cork of the stem and branches with perimeter at breast height greater than 70 cm is removed. Possibly this intervals are not the optimum for the production of cork. Most of the models that exist only predict cork weight for 9 or 10 years of cork age. But a new model developed by Paulo and Tomé (2010) allows the prediction of mature cork biomass with t years of growth, based in one measurement taken at any other age. The model is based on two sub-models; the first one predicts cork biomass with 9 years of age using four alternative models with different variables as inputs; and a second one that estimates cork back weight proportion at 9 years of age. The method has already been validated for 9, 10 and 11 years of cork age, and the objective of this work was doing the validation of the model for that ages and also adding new data of 8 and 13 years of cork age. The evaluation was done by comparing the observed and the estimated values of cork biomass from corks with 8, 9, 10, 11 and 13 years of age. According to previous validation, it was confirmed that the model work better as more input variables are added in the model and it was also found that as the ages of cork biomass move away from 9 years, as well as the extremes of cork thickness classes, the worst is the performance of the model
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De nombreux modèles numériques sont proposés dans la littérature en utilisant des méthodes d'éléments finis et d'éléments finis discrets pour étudier l'usure par frottement, ils incluent à peine l'effet des débris d'usure. Ces modèles étant coûteux en termes de calcul, simuler un grand nombre de cycles d'usure par frottement n'est pas réalisable dans la pratique. Une nouvelle méthodologie est proposée qui ne nécessite que des propriétés de matériau en vrac comme les coefficients de frottement / usure et utilise des méthodes semi-analytiques pour simuler l'usure par frottement avec des débris piégés. Dans cette approche, les débris sont supposés être attachés à l'une des surfaces pendant le processus de fretting. Les résultats obtenus à partir de cette approche ont été comparés avec des expériences de fretting. La méthode proposée permet de saisir la profondeur d'usure et la largeur des cicatrices, et les résultats sont très proches de ceux observés dans les expériences. L'assemblage des soupapes des moteurs à combustion subit une usure par frottement en raison d'un phénomène complexe impliquant une rigidité structurelle et une tribologie de contact. L'usure des soupapes a de nombreux effets néfastes sur les performances du moteur. Il provoque une récession de la soupape entraînant des changements dans les connexions du mécanisme d'entraînement de la soupape, ce qui perturbe l'ouverture et la fermeture des soupapes. Avec des normes d'émission strictes, l'utilisation de lubrifiant pour réduire la friction au contact est limitée. Si l'usure à travers la circonférence n'est pas uniforme, il y aura une fuite de gaz et le moteur donne moins de puissance. Il est nécessaire de bien comprendre la raison de l'usure des soupapes et de développer un modèle numérique capable de prédire l'usure par frottement de la soupape pour le nombre d'heures de fonctionnement donné. Des expériences ont été réalisées pour comprendre le mécanisme d'usure et calculer les coefficients d'usure qui peuvent être utilisés dans le modèle numérique. Un modèle d'usure numérique est construit qui capture la rigidité structurelle de l'ensemble de soupape et le mécanisme d'usure au contact du siège
Many numerical models are proposed in the literature using finite element and finite discrete element methods to study fretting wear, they barely include the effect of wear debris. These models being computationally expensive, simulating large number of fretting wear cycles is not practically feasible. A new methodology is proposed which needs only bulk material properties like friction/wear coefficients and uses semi-analytical methods to simulate fretting wear with entrapped debris. In this approach, debris are assumed to be attached to one of the surfaces during the fretting process. The results obtained from this approach were compared with fretting experiments. The proposed method permits to capture the wear depth and scar width, and results are very close to that observed in the experiments. Valve assembly of combustion engines undergo fretting wear due to a complex phenomenon involving structural stiffness and contact tribology. Valve wear has many detrimental effects on the engine performance. It causes valve recession leading to changes in connections of valve drive train in turn disturbing the opening and closing of valves. With stringent emission norms, usage of lubricant to reduce friction at the contact is restricted. If the wear across the circumference is not uniform, there will be leakage of gas and the engine gives lesser power output. There is a need to thoroughly understand the reason for valve wear and develop a numerical model that can predict valve fretting wear for the given number of operating hours. Experiments were performed to understand the wear mechanism and derive wear coefficients that can be used in the numerical model. A numerical wear model is built that captures structural stiffness of the valve assembly and wear mechanism at seat contact

Firing pin is a critical component in terms of firearm function. Tip of firing pin can break off due to repeated impact loading, which results in malfunction of the whole firearm. This master's thesis aims to propose changes in geometry of the firing pin so that new firing pin will be more durable against fatigue failure. Geometry and characteristics of the original firing pin are provided by company Česká zbrojovka, a.s. To determine the amount of fatigue damage for specific configuration of firing pin, computational model, which simulates impact loading of the firing pin during dry fire, is created. Finite element method with explicit formulation is used for the calculation. Parameters of geometry, which are assumed to have highest influence on fatigue life, are chosen based on the analisys of the original firing pin. These parameters are changed in further calculations, resulting in new configuration of the firing pin, which is approximately 15 % more durable against fatigue failure.

A presente dissertação teve por objetivo analisar o comportamento de misturas asfálticas modificadas, pelo processo seco, com o copolímero etileno acetato de vinila (EVA), resíduo sólido descartado pela indústria calçadista. Em razão das características do EVA, acredita-se que ele possa melhorar as características mecânicas de misturas asfálticas e a resistência ao desgaste. A maioria dos pesquisadores tem direcionado seus esforços em estudos de misturas asfálticas modificadas pelo processo úmido, porém, devido à natureza do resíduo analisado neste trabalho, optou-se pelo processo seco, que demanda menos energia por não necessitar de moagem do material. A pesquisa compreendeu o estudo de amostras de misturas asfálticas não envelhecidas e com envelhecimento de duas e quatro horas em estufa, com moldagem de corpos-de-prova para realização dos ensaios de resistência à tração por compressão diametral estática, módulo de resiliência por compressão diametral, fluência por compressão uniaxial estática e dinâmica, vida de fadiga e desgaste por abrasão (ensaio Cantabro). Os resultados mostram que a utilização deste resíduo aumentou a resistência das misturas à fadiga e ao desgaste de forma significativa, porém as misturas tornaram-se mais susceptíveis à deformação permanente. O tempo de envelhecimento de curto prazo se mostrou importante, pois aumentou a resistência das misturas à fadiga e à deformação permanente.
The main purpose of the present master thesis was to analyze the behavior of modified hot-mix asphalt, through the dry process, with the copolymer ethylene vinyl acetate (EVA) discarded by the footwear industry. Since the EVA characteristics, it is believed that it can improve hot-mix asphalt mechanic characteristics and the wear and tear resistance. Most of the researchers have been addressing efforts in studies on modified hot-mix asphalt by the wet process, however, due to the nature of the solid residue analyzed in this work, the dry process will demand less energy for not needing of grinding. The research evolved the study of samples of asphalt mixtures not aged and with aging of two and four hours in oven, submitted to indirect tension test, resilient modulus, static and dynamic creep, fatigue life and loss due to abrasion (Cantabro test). The results show that the use of this residue increased the resistance of the mixtures to the fatigue and loss of mass due to abrasion, however the mixtures became more susceptible to the permanent deformation. The short-time aging was shown important, because it increased the resistance of the mixtures to the fatigue and the permanent deformation.

Habitat degradation, fragmentation and loss are important factors causing loss in biodiversity and red listed species, and restoring habitats is essential in preventing this. However, there is a limited knowledge of the long term effects of restoration measures. This study focuses on analysing the long term restoration success of restoration measures carried out in a restoration program between the 1980's and early 2000's in locations of acidic fen, buffered fen, dry heather, wet heather, and wet grassland. The aim of the restoration program was to diminish the effects on ecosystems that were influenced by eutrophication, acidification, and dehydration. The locality species composition and Ellenberg values of nitrogen (EVN), moisture (EVM) and pH levels (EVpH) are analysed, by using previous and current restoration success scores from 54 locations in the province of Drenthe in the Netherlands. The dependence of restoration success score and Ellenberg values on change over time, habitat type, restoration method and EVN, EVM and EVpH are analysed. Restoration success depended on habitat type, with wet heather having significantly higher success compared to wet grasslands. The change in score over time, however, did not vary among habitats. Restoration success did not depend on restoration method(s), nor did change in restoration success. Ellenberg values varied among habitat types, and EVM changed significantly over time in dry heather, but was not significantly related to restoration success score. In conclusion, wet heather was shown to be doing quite well, but could benefit from additional restoration. Acidic fen, buffered fen, dry heather, and wet grassland have all shown poor long term restoration effects, indicating an overall need for further restoration measures. The results also highlight the importance of further studies into the effect of long term restorations, especially focused on finding successful restoration methods, and the importance of detailed data gathered in the field.

Background: An increasing number of operations on children are performed as day surgery and this experience of health care may affect future hospital stays. The aim of this qualitative study was to describe children´s experiences in connection with day surgery. Method: Ten children aged six to fifteen who had gone through general anesthesia at examinations or surgery were interviewed and the content was analyzed by systematic text condensation. Result: The core category “From uncertainty to relief with newly acquired experience” could summarize the result of this interview study. In the category “Uncertainty creates insecurity” all children expressed varying levels of anxiety for the anesthesia. The main causes for the worry were insufficient information or lacking experience from similar health care situation. "The concrete experience different from the qualm” describes that the discomfort the children expressed were different or slighter than expected. The anesthetization was easy and quick while the awakening was described as more unpleasant. In the category “Good nursing care creates security and trust” the children appreciated the staff and their way of informing and giving care. Many expressed an ease that the procedure had passed and would experience less anxiety before a possible future anesthesia; “Relieved and strengthened through experience”. Conclusion: The interviewed children had surprisingly little knowledge in advance of what would happen during the day and not to mention the procedure of anesthesia. Unpleasant experiences were described even during moments where it was not expected. To reduce the anxiety and discomfort the information in connection with day surgery needs to be substantially improved in this age group.

Bakgrund: Allt fler operationer på barn utförs polikliniskt och denna erfarenhet av sjukhusvård kan påverka upplevelsen vid framtida vårdtillfällen. Syftet med denna kvalitativa studie var att beskriva barns upplevelser i samband med dagkirurgi. Metod: Tio barn sex till femton år som genomgått sövning i samband med undersökning eller operation intervjuades och innehållet analyserades med systematisk textkondensering. Resultat: Temat ”Från ovisshet till lättnad med nyvunnen erfarenhet” kan sammanfatta resultatet av intervjustudien. I kategorin ”Ovisshet skapar otrygghet” uttrycktes oro i varierande grad inför sövningen vilken främst orsakades av otillräcklig information eller saknad erfarenhet av liknande sjukvårdssituation. ”Den konkreta upplevelsen annorlunda än farhågan” beskriver att obehagen barnen berättade om var annorlunda eller lindrigare än förväntat. Nedsövningen gick lätt och snabbt medan uppvaknandet beskrevs som mera obehagligt. Under kategorin ”God omvårdnad skapar trygghet och tillit” gav barnen positiva omdömen om personalen och deras sätt att informera och ge omvårdnad. Många uttryckte en lättnad över att ingreppet var genomfört och uppgav att de skulle känna mindre oro inför en möjlig framtida sövning; ”Lättade och stärkta av erfarenheten”. Slutsats: De intervjuade barnen hade överraskande lite kunskap i förväg om vad som skulle hända under dagen och inte minst narkosproceduren. Obehag upplevdes även under moment där det ej förväntades. För att minska oro och obehag behöver informationen i samband dagkirurgi förbättras avsevärt till denna åldersgrupp.

Doctor of Philosophy
Department of Entomology
Thomas W. Phillips
Robert "Jeff" J. Whitworth
Dry-cured ham is protected from infestations of Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) with the fumigant methyl bromide. Developing feasible alternatives to methyl bromide is necessary due to the phase out of methyl bromide. The effectiveness of food-safe compounds for preventing infestations of T. putrescentiae on dry-cured hams was evaluated by dipping ham pieces in solutions of various food additives. Propylene glycol (1, 2-propanediol), lard, ethoxyquin and butylated hydroxytoluene prevented or significantly reduced mite population growth. A combination of carrageenan + propylene glycol alginate + 40% propylene glycol was effective in reducing mite numbers on treated whole-aged hams compared with untreated hams. Dose/response tests with twelve registered residual insecticides were conducted to assess contact toxicity to T. putrescentiae. Three of these insecticides were evaluated for persistence over a 2-month period on different surfaces. Commercial formulations of deltamethrin plus chlorpyrifos-methyl, chlorfenapyr, and malathion showed promising results for contact toxicity against T. putriscentiae. Chlorfenapyr applied to metal, concrete, and wood resulted in 100% mortality of treated ham mites for up to 8 weeks. The effect of high and low temperatures on mortality of T. putrescentiae was studied in the laboratory. Groups of 10 eggs and groups of a mixture of 40 adults and nymphs were separately exposed to several high and low temperatures, ranging from +35 to 45°C and from −20 to +5°C, for several time periods. Eggs were found to be more tolerant to both high and low temperatures compared with adults and nymphs. Results showed that high temperatures from 40-45°C killed all T. putrescentiae eggs, adults, and nymphs within 4-1 d, while −10°C or lower killed all the same stages in less than 1 d. Combinations of the fumigant sulfuryl fluoride (SF) applied under high temperatures ranging from 25-40ºC, were studied to determine the highest temperature, shortest exposure time, and the lowest value of a concentration-by-time product (CTP) of SF against T. putrescentiae. Results showed that complete control of all life stages of T. putrescentiae was achieved at 40ºC with SF. More than one day of exposure was required to kill adults and nymphs and eggs at 40ºC at a CTP close to the EPA labeled rate of 1500 gh.m⁻³. Results indicated that adults and nymphs were more susceptible to SF compared to eggs. This study focused on investigating different control methods for T. putrescentiae in dry-cured ham facilities and most of examined techniques are preventive, although some of them can be applied as remedial methods after mite infestations are noticed.

Hollow fiber gas separation membranes manufactured from Poly(vinyl chloride) (PVC) have been produced via a dry/wet spinning method for end use in ozone/oxygen gas separations. Ambient temperature production mechanisms were initially targeted. A number of spin runs were undertaken changing aspects of the dope solution and the spinning conditions but produced only very low selectivity membranes. It was concluded that ambient condition spinning was unattainable for the solutions used. In order to explain the low selectivity a rheological study was undertaken which considered flow, oscillatory and creep rheological conditions and modelling of the flow patterns observed across the spinneret annulus. This study showed large differences between the dope at 20°C and 60°C in terms of viscosity and viscoelastic nature. These differences were predicted to make spinning difficult through slippage on the spinneret walls and viscoelastic nature of the solution. Spinning at elevated temperature was undertaken and used to produce membranes under different spinning conditions according to a Taguchi model and which would allow graphical comparisons also in order to assess the validity of the Taguchi analysis in these applications. The membranes produced an array of results all of which indicated solution diffusion through PVC as the controlling transport mechanism under the spinning conditions. Both graphical and Taguchi analysis concluded the same conditions to be optimal; low dope extrusion rate but high convective gas flow rate and residence time producing the best selectivity. The membrane permeation results were used alongside scanning electron microscopy images to model the active layer thickness in the membranes. This concluded that the higher selectivity membranes exhibited lower active layer thicknesses and porosity resulting from the quick formation of a dense surface layer for nodule coalescence preventing further mass transport and hence halting penetration of the active layer. Ozone/oxygen binary gas mixtures showed qualitative evidence of separation. Unfortunately due to equipment limitations it was not possible to provide quantitative data to support this. The membranes have displayed good resistance to oxidative environment and therefore they perhaps offer a viable solution for processes occurring in this type of environment which more common membrane materials may not be suitable for.

The aim of the master´s thesis was to verify the applicability of elemental analysis and molecular spectrometry for examining the authenticity of ketchup. For verify of share refractometric dry matter introduced into ketchup from tomatoes was used analysis of potassium and lycopene content. Ketchups with different tomato contents were prepared and subsequently models were created, which were used to verify the proportion of refractometric dry matter introduced into tomato ketchup in ketchups from the store. The results of the work showed that the amount of lycopene is a problematic marker for verifying the authenticity of ketchup, because during the production of ketchup, lycopene is degraded.In contrast, the amount of potassium in ketchup has been shown to be a good marker for monitoring the authenticity of ketchup. The model based on the potassium content of ketchup worked reliably, the deviations obtained from the quantity of tomatoes used for the production of ketchup indicated on the packaging were less than 10%. Higher deviations were achieved in ketchups with a minimum permitted tomato content of up to 20%. The concentration of potassium in ketchup with a lower content of used tomatoes can be significantly affected by the addition of other ingredients to the ketchup (onion, garlic, carrot, apple, etc.). In addition to the ketchup production technology used, the ripeness of tomatoes also has a significant effect on the model for verifying the authenticity of ketchup.

Dans cette étude, l’intérêt est porté sur l’effet des conditions opératoires sur l’enrobage en voie sèche de grosses particules « hôtes » par de fines particules « invitées » et aussi sur la modélisation de cet enrobage selon la méthode par éléments discrets (DEM) afin de mieux comprendre les phénomènes mis en jeu. Dans ce travail, les matériaux choisis comme particules hôtes sont les Suglets® et les particules invitées sont en stéarate de magnésium (StMg). Ces deux éléments sont introduits dans un mélangeur à fort taux de cisaillement, le Cyclomix. Les propriétés du produit final, comme la coulabilité, la mouillabilité et le degré d’avancement de l’enrobage, ont été caractérisés. La variation des propriétés est étudiée en fonction de la durée de traitement dans le Cyclomix pour diverses vitesses de rotation, taux de remplissage et rapport de taille de particules hôte et invitée. La coulabilité a été améliorée avec la durée du mélange ou la vitesse de rotationLe degré d’avancement présente une tendance semblable pour différentes conditions opératoires. Sa variation est représentée par une loi exponentielle empirique en fonction du temps de mélange, paramétrée par une constante ajustable. Cette constante permet d’estimer l’efficacité de l’enrobage. La simulation des mouvements de particules dans le mélangeur par DEM a permis d’obtenir des informations sur la position, la vitesse des particules, et d’autres paramètres énergétiques. Les champs de vitesse réelle ou numérique liés aux mouvements de particules, analysés par PIV (Particule Image Velocimetry), sont analogues. La constante d’enrobage dépend de la vitesse de rotation simulée et peut être ainsi prédite par DEM
Investigations of the effect of the operating conditions on the dry coating and the motion of particles in a high shear mixer by the DEM simulation have been done. Big Suglets® and small Magnesium Stearate materials have been chosen for the dry coating process. The treatment has been carried out in a Cyclomix, a high shear mixer, at different mixing time, rotational speeds, filling ratio of the samples and particle size ratio to observe the effect of the operating conditions on the dry coating. A conversion ratio has been introduced to quantify the degree of coating and measured. The flowability has been improved when increasing the operation time in the mixer. Higher speeds of rotation can improve the flowability more rapidly. However, the flowability doesn’t seem to be sensitive to the filling ratio. The curves of conversion ratio versus time exhibit the same kind of variations for different operating conditions. It is possible to approximate this tendency by an exponential function in which a characteristic parameter “coating rate constant” is introduced, linked to the efficiency of the dry coating process, since the conversion ratio shows a linear relation with a flowability index and the wettability angle. Simulation of the particle motion in the mixer has been carried out by a Discrete Element Method: different parameters characterizing the location, the velocities, and the attachment of the particles have been derived. The velocity fields of the real and simulated particle motions, compared by Particle Image Velocity (PIV), are quite similar, validating the DEM method and allowing the prediction of the coating process

Thesis (M. S.)--Aerospace Engineering, Georgia Institute of Technology, 2010.
Committee Chair: John-Paul Clarke; Committee Member: Ellis Johnson; Committee Member: Eric Feron. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Background: Studies of assessing dietary fluoride intake in children have employed different dietary methods mainly “2-day duplicate” and “3-day food diary” methods. However, none of these methods have been validated or standardised. Main aims: The main aims of the current study were to develop a better understanding of strengths and weaknesses of dietary assessment methods “2-day duplicate plate” and “3-day food diary” by comparing dietary fluoride intake estimated by each method and evaluate the validity of the two methods for estimating dietary fluoride intake in young children. Methods: Sixty one healthy 4-6 year old children living in fluoridated area of the north-east of England since birth were recruited via 10 primary schools. Dietary information was collected using “2-day duplicate plate” and “3-day food diary” methods. Two 24-h urine samples and two samples of post brushing expectorate (a mixture of saliva, toothpaste and water used to rinse after brushing) from each child. Completeness of 24-h urine samples was checked using urinary excretion of creatinine and urinary flow rate. Validity of the two dietary assessment methods was checked by measuring urinary excretion of nitrogen and potassium as independent validity checks. Total daily fluoride intake from diet and toothpaste ingestion and urinary fluoride excretion was determined for each child. Results: All participated children completed all aspects of the study. According to the validity criteria, dietary data of 58 (95%) children, when collected by the 3-day food diary, were considered valid. However, when the dietary data were collected by the 2-day duplicate plate method, the data for 46 (75%) children were viewed as valid. Mean total dietary fluoride intake was 0.533 mg/d by the 3-day food diary method and 0.583 mg/d by the 2-day duplicate plate method. No statistically significant difference in total dietary fluoride intake was observed between the two methods. The mean difference in estimated dietary fluoride intake by the two dietary assessment methods was -0.050 mg/d with 95% limits of agreement of -0.501 to + 0.401 mg/d. Conclusion: Either the 3-day food diary or the 2-day duplicate plate method can be used when investigating mean total daily dietary fluoride intake of a population. However the methods cannot be used interchangeably at the individual level.

Trial and error and the use of highly time-consuming methods are often necessary for modeling, simulating and characterizing nonlinear dynamical systems. However, for the rather common special case when a nonlinear system has linear relations between many of its degrees of freedom there are particularly interesting opportunities for more efficient approaches. The aim of this thesis is to develop and validate new efficient methods for the theoretical and experimental study of mechanical systems that include significant zero-memory or hysteretic nonlinearities related to only small parts of the whole system. The basic idea is to take advantage of the fact that most of the system is linear and to use much of the linear theories behind forced response simulations. This is made possible by modeling the nonlinearities as external forces acting on the underlying linear system. The result is very fast simulation routines where the model is based on the residues and poles of the underlying linear system. These residues and poles can be obtained analytically, from finite element models or from experimental measurements, making these forced response routines very versatile. Using this approach, a complete nonlinear model contains both linear and nonlinear parts. Thus, it is also important to have robust and accurate methods for estimating both the linear and nonlinear system parameters from experimental data. The results of this work include robust and user-friendly routines based on sinusoidal and random noise excitation signals for characterization and description of nonlinearities from experimental measurements. These routines are used to create models of the studied systems. When combined with efficient simulation routines, complete tools are created which are both versatile and computationally inexpensive. The developed methods have been tested both by simulations and with experimental test rigs with promising results. This indicates that they are useful in practice and can provide a basis for future research and development of methods capable of handling more complex nonlinear systems.

I industrilokaler består golven i många fall av betong. Det är ett problem när dessa golv spricker på grund av krympning eller temperaturvariationer. Idag finns tekniker som på ett bra sätt förklarar orsaker till dessa sprickor och om dessa tekniker kombineras på ett korrekt sätt skulle sprickbildningen kunna förutses och undvikas. Behovet att utveckla ett pålitligt och användarvänligt system för beräkning av sprickrisken i industrigolv är därav stort. Att ta fram en metod för avgörande av sprickbildning på grund av krympning är syftet med detta arbete. Krympning är definierat som reduktionen i volym av en obelastad betongyta som befinner sig under konstant temperatur och anges som en töjning, ߝ ௌு . Det orsakas främst av den förminskning av vatten i betongen som sker under betongens härdningstid. Krympning kan ske antingen helt autogent genom att försegla betongen eller kombinerad autogen- och uttorkningskrympning då betongprovet tillåts torka fritt utåt i en eller flera riktningar. Det finns programvaror som kan beräkna temperaturförloppet i en torkande betong och även fukthalten och spänningarna. Dessa programvaror kommer att utnyttjas i detta arbete för att utveckla en metod för bedömning av sprickrisken. Utgångspunkten är laboratoriemätningar på krympning för åtta olika betongrecept samt beräkningar för ett typfalls förångningsbara vattenhalt genom hela tvärsnittet. Anpassningar till dessa görs med hjälp av minstakvadratmetoden och problemlösaren i Excel som använder sig av icke-linjär regressionsanalys GRG. Utgångspunkten för att ta fram de nödvändiga krympparametrarna: ultimat referenskrympning, den empiriska konstanten som avgör krökningen av krympningsutvecklingen samt en empirisk parameter som representerar tiden då lutningen på krympningen förändras i tid, är en funktion för att beräkna töjningen i betongprovet som uppstår på grund av krympningen. Viktigt för beräkningar av krympningen är den temperaturekvivalenta tiden som dock inte har någon inverkan på de beräkningsfall där betongen härdar inomhus i 20°C. Krympparametrarna kan införas i olika vertikala punkter i en betonggjutning i programvaran ConTeSt som sedan kan beräkna temperatur- och spänningsutvecklingen i betongen. Dessa jämförs med betongens hållfasthet och ett resultat om utnyttjandegraden uttryckt som spänning/hållfasthetskvot uppnås. Alla analyserade recept och fall i detta arbete får resultatet att de spricker på grund av krympningen. Dock är dessa resultat inte korrekta då fel mekaniska materialegenskaper var tvunget att användas. Om de testade fallen spricker eller inte är dock inte syftet med arbetet. Beräkningarna gick igenom och ett resultat åstadkoms vilket var det som behövde undersökas. Metoden fungerar men är inte användarvänlig. Det är mycket manuell inmatning och det vore av stor betydelse för framtida användning av denna metod att en förbättrad och enklare programvara med de rätta funktionerna finns tillgänglig.

L'étude présentée dans ce document a pour objet l'étude de différents modes de réduction de vibrations dans les structures avec liaisons. Le premier mode étudié se base sur la dissipation d'énergie apportée par la déformation d' éléments piézoélectriques connectés à un circuit électrique adapté. Le second mode proposé se base sur la propriété de la liaison boulonnée à changer les fréquences propres d'une structure en fonction du serrage appliqué. Cette propriété est utilisée avec plusieurs lois de contrôle du serrage afin d'éviter les plages de fréquences critiques. Ensuite une étude probabiliste est effectuée pour déterminer la robustesse de la réduction de vibrations par rapport à la variation de certains paramètres du modèle. Cette étude de robustesse est effectuée à travers des méthodes stochastiques non-intrusives, parmi lesquelles une méthode originale proposée. Elle permet une réduction de la taille du modèle stochastique à résoudre, ce qui réduit très considérablement le temps de calcul sans perte de qualité significative.

Randomized complete block designs with three replications were utilized to evaluate the effects of fumigation with sulfuryl fluoride (SF) (0, 12, 24, 36 and 72 mg/L), phosphine (PH₃) (0, 200 and 1000 ppm at 48 hr), methyl bromide (MB) (0, 4, 8, 16, and 32 mg/L for 48 hr), carbon dioxide (CO₂) (0, 60% at 48 hr and 60% at 96 hr) and ozone (O₃) (0 ppm and 175 ppm for 48 hr) on the volatile flavor compound concentrations in dry cured ham. Fluoride and SF concentrations increased (P < 0.05) in dry cured hams as SF fumigation concentration increased, but all samples contained fluoride and SF concentrations below the legal limits of 20 and 0.01 ppm, respectively. Also, as phosphine fumigation concentration increased, the residual concentration of phosphine also increased in the hams (P < 0.05), but all samples contained levels that were lower than the legal limit of phosphine in stored food products (0.01 ppm). Minimal differences existed in the presence and concentration of aroma active compounds in fumigated hams when compared to the control. Triangle tests indicated that consumers could not discern (P > 0.75) between the control hams and the fumigated hams. This study revealed that there were minimal aroma/flavor differences among control hams and hams that were fumigated with SF, PH₃, MB, CO₂ or O₃ and that fumigation of dry cured ham with SF and PH₃ were safe and met legal requirements for consumption. This reveals that SF, PH₃, CO₂ and O₃ could be tested at the industrial level to determine their efficacy as potential alternatives to methyl bromide to treat dry cured hams for insect pests.

This dissertation describes the elucidation and implementation of derivatisation in the quantification of biologically active vitamin D metabolites in limited volume serum and dry blood spot samples (DBS) using the liquid chromatography tandem-mass spectrometry (LC-MS/MS) analytical technique. This manuscript describes in detail the development and validation of an analytical methodology, highlighting the role derivatisation and mass spectrometry plays in the structural characterisation and quantification of vitamin D metabolites. The first chapter reviews comprehensively, the history of vitamin D biosynthesis discovery as an anti-rickets agent, the biochemistry of vitamin D, its metabolic pathway, functions in the different biological systems and the consequences of its deficiency in the body. The second chapter reviews the current methods and techniques utilised for the detection and characterization of vitamin D metabolites, with specific emphasis based on the contribution made by derivatisation and mass spectrometry. A brief introduction to derivatisation is provided, with specific focus on PTAD and Amplifex diene reagents (Cooksontype reagents) used in this study. The importance of sensitivity and selectivity of targeted analytes is described first in detail for underivatised analytes, followed by PTAD and Amplifex derivatised samples. Chapter 2 also describes the importance of vitamin D quantification using liquid chromatography, the strengths and limitations of LC-MS/MS when used in isolation and after derivatisation. Also discussed, is how combining these techniques can overcome inherent limitations in LCMS/MS and enhance analytical performance. In Chapter 3 the materials and methods used and the study design is laid out, describing a brief introduction of the routinely used clinical diagnostics assay enzyme-linked immunosorbent assay (ELISA) as a reference method and is compared to an LC-MS/MS assay, to ascertain discrepancies and agreement between both methodologies from the same volunteer samples. Chapters 3 and 4 describes the comprehensive development, optimisation and validation of the highly sensitive PTAD derivatives LC-MS/MS assay for the quantification of active vitamin D metabolites, as well as the development of method using Amplifex diene derivatisation. Also discussed, is sample preparation optimisation of DBS and Mitra micro-samples. A holistic approach was taken to the development of the methodologies to provide data from which the required analytical information can be obtained for method evaluation and statistical analysis. The validated PTAD derivatives method is applied to the quantification of vitamin D metabolites in limited volume (100 μL) clinical human serum samples from 30 volunteers compared to results obtained using the clinical diagnostics ELISA technique. In Chapter 4 data analysis is described and the results are further discussed and a conclusion made based on the findings from the study. This study envisaged that combination of limited sample volume and DBS, derivatisation and LCMS/ MS is a powerful tool in vitamin D metabolite analysis and provided evidence of a positive increase in sensitivity and selectivity between derivatised compared to underivatised samples. A 10-fold increase in signal-to-noise-ratio (S/N) was observed when comparing PTAD derivatised, and Amplifex diene derivatised versus underivatised samples. Chapter 5 presents suggested future directions and considerations in the areas of vitamin D metabolite derivatisation and DBS sampling technique analysis using LC-MS/MS research based on the results presented in this dissertation.
Dissertation (MSc)--University of Pretoria, 2017.
Pharmacology
MSc
Unrestricted

This thesis investigates the feasibility of loading silicone hydrogel (SiHy) contact lenses with two different hydrophobic therapeutics, latanoprost and DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine), for treatment of glaucoma and hyperemia respectively. The two methods of loading were 1) thermal loading in an aqueous medium and 2) convective loading in a solution of n-propanol. Dailies Total1® lenses prepared in this manner were tested for their loading and their release into artificial tears. Continuous release over 1-4 days at therapeutic levels is achievable from thermal loading of DMPC, convective loading of DMPC, and convective loading of latanoprost. The DMPC loading processes can be naturally integrated into standard manufacturing lines for Dailies Total1®. Both DMPC and latanoprost release at rates proportional to the amount loaded into a contact lens. Latanoprost loads into a contact lens strictly proportionally to the loading concentration and the time of loading. The convective loading step represents a significant improvement on both the time of loading (reduced from days to minutes) and the loading capacity of silicone hydrogel contact lenses. This thesis also compares the loading and release of latanoprost in the convective loading procedure using the SiHy contact lenses of Acuvue Advance® (Johnson & Johnson Vision Care, Jacksonville, FL) , Air Optix® (Alcon, Copenhagen, Denmark), Biofinity® (CooperVision), PureVision® (Bausch & Lomb), and Dailies Total1® (Alcon), and the polyHEMA lens, SofLens 38® (Bausch & Lomb), finding that silicone hydrogels load an order of magnitude more drug than the polyHEMA lens and release into artificial tears for an order of magnitude longer. Overall, these experiments provide a quantitative understanding of the dynamics of loading and release for both DMPC and latanoprost.

碩士
國立成功大學
環境工程學系碩博士班
90
Dry deposition is the importance mechanism by which pollutants are removed from the atmosphere. The techniques for measuring dry deposition have been developed over the years. However, there is not a standard measurement method which can be accepted and used as yet. The divergency of results in estimates of dry deposition by each measurement method approach one or two order of magnitude, due to uncertainties of environment and complexities of atmospheric flow condition. The dry deposition rates of gaseous and aerosol species was measured in field condition simultaneously by means of vertical gradient and surrogate surface method in this study. The objectives of this study are: (1) evaluate the applicability of the two methods, (2) compare measurement results to figure out the correlativity and differentiation between the two methods. All the sampling campaign was conducted in daytime. For vertical gradient method, sampling was performed at five heights(2, 4, 7, 13, 24 m). For surrogate surface method, the dry deposition flat plates were deployed at a 7-m platform. The sampling time is 4 hr and 8 hr for vertical gradient method and surrogate surface method, respectively. Particles were collected by teflon filters; gaseous HNO3 and SO2 were absorbed by quartz filters coating K2CO3 solution; NH3 was absorbed by quartz filters coating citric acid solution. The measurement results of surrogate surface method show that the particle deposition flux to the upper surfaces is always higher than that to the lower surfaces, especially the coarse particle, due to gravity. Nevertheless, gaseous species in atmosphere are transported mainly by molecular diffusion, and molecular diffusion occurs independently of direction. Therefore, the deposition flux of gaseous species to the upper surface is almost equal to the lower surfaces. For HNO3, SO2 and NH3 the ratio of the upper surface flux to the lower surface flux is 1.0, 0.95 and 1.04, respectively. As for the comparison of dry deposition fluxes of aerosol species, the results of measured by vertical gradient method are always larger than that measured by surrogate surface method. Of all aerosol species, the divergency of NO3-, SO42- and NH4+ is one order of magnitude and only Ca2+ is well correlated, R2 is 0.68.The divergency of gaseous species is much smaller than aerosol species. The correlation coefficient R2 of SO2 and HNO3 is 0.63 and 0.65, respectively.

碩士
中原大學
機械工程研究所
98
In recent years, the supply chains in liquid crystal display (LCD) industry are flourished in Hsin-Chu city, Taiwan due to the successful integration of the opto-electronic industry. Nowadays not just it is one of the most significant industries in Taiwan but also its industrial value is the number one in the top ten of opto-electronic industries. The accumulative amount of relative investment is more than hundred billion Taiwanese dollars and the government has identified LCD and semiconductor industry as dual trillion-industries in Taiwan considering their enormous value. LCD companies and corporations are looking forward to another economic miracle by integrating and combining all resource of the industry. Recently the demand for TFT-LCD is growing because of the important role it plays in consumer electronic products such as cell phones and LCD TVs. People start to pay attention to the quality of LCD especially when this industry and market is competitive and quickly changing. TFT LCD products are tending to become thinner, lighter and brighter than before. The quality in the product and low deficient rate in the production are the keys for high-end products. This research describes the quality of substrate structure in the dry etching process and the two-method experiment design which is try-and-error solution and the Taguchi method. Then, the experiment analysis and error of data are mentioned in the paper, which also points out the research results. The result from the best experiment describes the amounts of particle are less by using the Taguchi method. By the result of Taguchi method, the best experiment parameter is Dry pump 100(mT), up electrode hold size is 1.2(mm)、glass lift pin materials use PBI、Clamp form glass gap is 0.8(mm).The original number of particles is 30-70 per, distribution condition improve form a great quantity to disseminate type. After improvement, distribution condition improve form small to disseminate type, Particle practice improve is 25（%）.The result of the following research shows that we can get the best parameters in 8 experiments by Taguchi method, which is better than 23 experiments by the old method. The old method has a longer process wasting more time and money. The result is worse, too. However, Taguchi method is easier. In other words, we are able to control experiment conditions easily according to the parameters. It spends less time and money. The experiment will be completed rapidly.

碩士
南開科技大學
福祉科技與服務管理所
98
The purpose of this investigation is using Bioelectrical Impedance Analysis Methods (BIA) to estimate the changes of hydration status of patients. Sixty patients (20 males and 40 females) were randomly selected from long-term hemodialysis patients and the dialytic process was divided into 6 time periods. The resistances, reactances, Blood Pressure (BP), patients’weights were measured in each time points. Meanwhile, the neural network algorithm and the multiple regression analysis method were utilized to estimate dry weight by parameters obtained from six time points such as diastolic blood pressure, ratios of bio-impendence vector norm and weight. Comparing the dry weight obtained from calculated methods to the dry weight given by clinicans’trial and error method, the root mean square error of the neural network algorithm was 0.68 and the root mean square error of the regression analysis method was 0.7 in female. Simultaneously, the root mean square error of the neural algorithm was 5.06 and the root mean square error of regression analysis method was 1.46 in male. The plane composed of resistance－reactance could display status of hydration of a patient during the intradialytic period. When weight gained within 5% of dry weight during inter-dialytic period, then the vector clusters shifted towards the tolerance ellipse’s central zone. However, when weight gained over 5% of dry weight during inter-dialytic period, the vector clusters of diabetic patients with lower blood pressure were stayed in the edema zone and that were not moving towards to the tolerance ellipse’s central zone. When weight gained less 5% of dry weight during inter-dialytic period, BMI were about 21.85, lean patients, the vector cluster of patients were stayed in the lean zone and that were moving outward the tolerance ellipse’s central zone. This method combined with bioimpedance analyzer can provide the clinician suggestions for new patients’ dry weight estimation, meanwhile, and it also could help patients to know their hydration status.

碩士
國立高雄大學
應用化學系碩士班
100
The purpose of this study is to develop a dry gel method for preparing order and porous films on metal substrates with improved surface properties as well as corrosion-resistant and scratch resistant properties. The dry gel method is firstly to coat the aluminum substrate with a zeolite seed precursor and then transform it directly to zeolite crystals in the presence of water vapor. On the other hand, by the conventional wet gel method, zeolite films grow via in-situ crystallization on top of aluminum substrates. Different thickness and crystal sizes can be controlled by varying synthesis recipes and reaction conditions and time. The anti-corrosion properties of various metal oxide films were evaluated electrochemically by means of Tafel plot. The anti-corrosion property of the as-synthesized zeolite films is attributed to the formation of nonporous passivation layers in the presence of structure directing agent for blocking Al substrates from the attack of air and humidity. The dry gel conversion of pre-deposited MFI zeolite precursor gel was demonstrated as an effective means for the preparation of anticorrosion coating on aluminum alloy. A 10 μm thick dense film, consisted of closely packed pure silica MFI nanocrystals was obtained in a short process time. The MFI film prepared by dry gel method is more smooth and hydrophilic than that prepared from wet gel method. A better anticorrosion performance was found comparing to the zeolite coating prepared by the conventional in-situ crystallization method in both NaCl and acidic solution. In case of wet gel method, very thick film is required for adequate corrosion resistance generating low corrosion current. There is no clear relationship between the thickness of the MFI membrane and its corrosion resistance. Modification of alkyl silanes on the MFI films prepared with both methods increases their hydrophobicity and thus corrosion resistance properties. The proposed dry gel method eliminates the suspended zeolite that always produces along with the conventional process, thus reduces waste. The need of a TEFOLN lined reactor could also be relaxed. Consequently, a zeolite anticorrosion coating can be applied more cost-effectively onto larger substrates. Furthermore, mesoporous silica film was successfully grown on aluminum substrate, showing good corrosion resistance properties. After removal of cetyltrimethylammoniumammonium bromide (CTAB) surfactant during high temperature calcination, mesoporous silica films lose their corrosion resistance properties. The corrosion resistance of the calcined mesoporous silica was restored by back loading to saturation with CTAB and benzotriazole (rust inhibitor). The corrosion resistance of the calcined mesoporous silica was poor in case of unsaturated loading or loading with quaternary C3 and C12 halide compounds. Therefore, surfactant molecules act as sealants mesoporous silica film and contribute corrosion resistance property.

碩士
朝陽科技大學
環境工程與管理系碩士班
90
Sulfate-contained particulate dry depositions by observing the deposited particulate at traffic intersection, coastal, and suburban areas were investigated. The deposited samples were coated with barium chloride (BaCl2) in the vacuum evaporator an then exposed to a relative humidity of 85% for 2 hours to form distinctive products for sulfate-contained particulates. The samples were observed by scanning electron microscopy. The major results are as follows : 1. Average volume shape factor (Sv) value of total particulate at traffic intersection was significantly higher than those at coastal and suburban areas, which suggests that sulfate-contained particles at traffic intersections are more irregular. 2. Dry deposition fluxes estimated by mass of collected particulate divided by the collecting surface area and time were comparable to the values estimated by observing the deposited particulate. 3. The NMDs of sulfate-contained particulate were 0.407, 1.21, and 0.823 μm at traffic intersection, suburban, and coastal areas. Traffic intersection site had small NMD, which shows that most sulfate-contained deposited particulates existed in fine diameter range. The MMDs of sulfate-contained particulate were 8.78, 14.9, and 19.5 µm at traffic intersection, suburban, and coastal areas, which were much higher than NMDs. 4. Sulfate-contained particulates less than 10 μm contributed 28.6%, 7.08%, and 7.64% to total dry deposition at traffic intersection, suburban, and coastal areas, respectively. The contribution of fine particulate was significantly higher at traffic intersection site. 5. Average number of sulfate-contained particulate in total particulate 32.8%, 21.8%, and 33.2% at traffic intersection, suburban, and coastal areas. The percentage of sulfate-contained particulate was lowest at suburban area.