Charles University Faculty of Pharmacy in Hradec Králové Department: Department of Pharmaceutical Chemistry and Pharmaceutical Analysis Student: Marie Šilhanová Supervisor: doc. PharmDr. Radim Kučera, Ph.D. Title of diploma thesis: The influence of solubility and adsorption on plastic materials on transport experiments From transport experiments on cell culture models we get valuable information about transport mechanism of drugs in organism. In vitro experiments are conducted for example on Transwell type inserts. During the experiment it was discovered that the results are not homogeneous, and the quantity of a substance in the solution decreases apparently, the reason behind this is inadequate solubility of lipophilic substances or their adsorption on the surface of plastic materials used in the experiment. Due to these problems we experience significant bias. This thesis is focused on antivirotics that did not perform well during transport experiments. First, HPLC/MS methods were developed, and they were used for concentration measurement of samples containing individual antivirotics. The drugs were tested under wide range of conditions so possible changes in effects of adsorption on plastic surfaces and solubility of drugs could be observed. The substances were divided into groups based on...

Frac-pack design is still done on conventional hydraulic fracturing models that employ linear elastic fracture mechanics. However it has become evident that the traditional models of fracture growth are not applicable to soft rocks/unconsolidated formations due to elastoplastic material behavior and strong coupling between flow and stress model. Conventional hydraulic fracture models do not explain the very high net fracturing pressures reported in field and experiments and predict smaller fracture widths than expected. The key observations from past experimental work are that the fracture propagation in poorly consolidated sands is a strong function of fluid rheology and leak off and is accompanied by large inelastic deformation and shear failure leading to higher net fracturing pressures. In this thesis a numerical model is formulated to better understand the mechanisms governing fracture propagation in poorly consolidated sands under different conditions. The key issues to be accounted for are the low shear strength of soft rocks/unconsolidated sands making them susceptible to shear failure and the high permeabilities and subsequently high leakoff in these formations causing substantial pore pressure changes in the near wellbore region. The pore pressure changes cause poroelastic stress changes resulting in a strong fluid/solid coupling. Also, the formation of internal and external filtercakes due to plugging by particles present in the injected fluids can have a major impact on the failure mechanism and observed fracturing pressures. In the presented model the fracture propagation mechanism is different from the linear elastic fracture mechanics approach. Elastoplastic material behavior and poroelastic stress effects are accounted for. Shear failure takes place at the tip due to fluid invasion and pore pressure increase. Subsequently the tip may fail in tension and the fracture propagates. The model also accounts for reduction in porosity and permeability due to plugging by particles in the injected fluids. The key influence of pore pressure gradients, fluid leakoff and the elastic and strength properties of rock on the failure mechanisms in sands have been demonstrated and found to be consistent with experimental observations. / text

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Made available in DSpace on 2015-05-08T14:53:33Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4041538 bytes, checksum: 728410878250239ee3b06a2310602806 (MD5) Previous issue date: 2013-10-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In Brazil, especially in Northeastern region, the wood used in civil construction, is almost all from Amazonian forest. The reduction of its consumption will be an environmental benefit. The utilization of waste plastics that are randomly thrown everywhere, would also be beneficial to the environment. In this work, we tried to verify the technical viability of a product made from waste plastic as frechal for housing, replacing the wooden parts commonly used for such. A literature review on single-family construction, plastic material and new product development was initially made. Material properties such as density, compressive strength, flexural strength, resistance to concentrated loads were studied. The results showed that the tested product, although flexible, it applies well in frechal function because there it works continuously against the wall top. / A redução no campo da construção civil do consumo de madeira, que no Brasil, e sobretudo no Nordeste brasileiro, é quase toda originária do que resta da floresta amazônica, seria um benefício ambiental considerável para o país. O aproveitamento de resíduos plásticos que são lançados aleatoriamente por toda parte, também seria de muito valor para o meio ambiente. Neste trabalho, procurou-se verificar a viabilidade técnica do emprego de um produto feito com resíduos de plástico, desempenhando o papel de Frechal, para emprego em habitações, em substituição às peças de madeira comumente usadas para tal. Foi inicialmente feita uma revisão bibliográfica sobre construções unifamiliares, material plástico e desenvolvimento de novos produtos. Foram estudadas as propriedades do material tais como densidade, resistência à compressão, resistência à flexão, resistência a cargas concentradas. Os resultados mostraram que o produto testado, apesar de ser flexível, aplica-se bem na função de frechal, porque ali trabalha apoiado continuamente na parede.

Der Übergang von einer linearen Wirtschaftsweise zu einer Kreislaufwirtschaft hat gerade erst begonnen. Beim Umgang mit Kunststoffen wird deutlich, dass die Kreislaufführung noch nicht in dem Maße erfolgt, dass die möglichen Potenziale der Rückführung von verwertbaren Kunststoffabfällen in den Produktionskreislauf ausgeschöpft sind. Im Rahmen der Arbeit wurden 16 Maßnahmen zur Steigerung der Mengen des eingesetzten Rezyklats ausgewählt, charakterisiert und hinsichtlich deren Kosten für die Umsetzung und erzielbaren Mengeneffekte berechnet. Die ermittelten Werte wurden in Anlehnung an die Methode der Ökoeffizienzanalyse miteinander in Zusammenhang gebracht. Dabei wurde angenommen, dass mit jedem Mg durch die Maßnahmen zusätzlich bereitgestelltes Rezyklat eine Einsparung von CO2-Äquivalentemissionen erreicht wird.

Cleavage fracture in ferritic steels can be defined as a sequence of few critical steps. At first nucleation of a microcrack takes place, often in a hard inclusion. This microcrack then propagates into the surrounding matrix material. The last obstacle before failure is the encounter of grain boundaries. If a microcrack is not arrested during any of those steps, cleavage takes place. Temperature plays an important role since it changes the failure mode from ductile to brittle in a narrow temperature interval. In papers A and B micromechanical models of the last critical phase are developed (cleavage over a grain boundary) in order to examine the mechanics of this phase. An extensive parameter study is performed in Paper A, where cleavage planes of two grains are allowed to tilt relative each other. It is there shown that triaxiality has a significant effect on the largest grain size that can arrest a rapidly propagating microcrack. This effect is explained by the development of the plastic zone prior to crack growth. The effect of temperature, addressed through a change in the visco-plastic response of the ferrite, shows that the critical grain size increases with the temperature. This implies that with an increasing temperature more cracks can be arrested, that is to say that less can become critical and thus that the resistance to fracture increases. Paper B shows simulations of microcrack propagation when the cleavage planes of two neighboring grains are tilted and twisted relatively each other. It is shown that when a microcrack enters a new grain, it first does it along primary cleavage planes. During further growth the crack front is protruded along the primary planes and lags behind along the secondary ones. The effect of tilt and twist on the critical grain size is decoupled with twist misorientation offering a greater resistance to propagation. Simulations of cracking of a particle and microcrack growth across an inclusion-matrix interface are made in Paper C. It is shown that the particle stress can be expressed by an Eshelby type expression modified for plasticity. The analysis of dynamic growth, results in a modified Griffith expression. Both findings are implemented into a micromechanics-based probabilistic model for cleavage that is of a weakest link type and incorporates all critical phases of cleavage: crack nucleation, propagation over particle-matrix interface and into consecutive grains. The proposed model depends on six parameters, which are obtained for three temperatures in Paper D using experimental data from SE(B) tests. At the lowest temperature, -30° , the model gives an excellent prediction of the cumulative failure probability by cleavage fracture and captures the threshold toughness and the experimental scatter. At 25º  and 55º  the model slightly overestimates the fracture probability. In Paper E a serie of fracture experiments is performed on half-elliptical surface cracks at 25º in order to further verify the model. Experiments show a significant scatter in the fracture toughness. The model significantly overestimates the fracture probability for this crack geometry. / QC 20100910

This thesis deals with 3D printing, materials used for 3D printing, testing of the materials and learning their real parameters. Goal of the thesis is comparing selected materials, executing series of mechanical test and selecting suitable material for printing high-quality plastic parts for use in automobiles, especially for reproduction of parts that are no longer made for oldtimers and for use in motorsport.

Work with behind-go recycling waste with project on foundation firm applied in this branch. Next then by suggesting arrangement on recycling electric cable, development prises and processing price list.

Zunehmendes Downsizing und der Trend zum Leichtbau bei Welle-Nabe-Verbindungen erfordern eine exakte Beschreibung des Systemverhaltens. Elastische Simulationen erfordern im Post-processing die Analyse komplexer Zusammenhänge, welche oftmals nur empirisch begründet sind. Elastisch-Plastische Materialmodelle geben die Möglichkeit Stütz- und Setzeffekte von Passfederverbindungen bereits während der Simulation abzubilden. Die vorliegende Arbeit wendet elastisch-plastische Materialmodelle auf Passfederverbindungen an, um auftretende Versagensmechanismen zu beschreiben. / Downsizing and the trend to lightweight design ofshaft-hub-connections need an accurate description of the behaviour of the system. In post-processing, elastic simulations require a complex analysis based on empiric formula. Using elastic-plastic material models enable the possibility to respect support and set effects of feather key connections within the simulation. The current paper applies elastic-plastic material models to feather key connections in order to describe occurring failure mechanisms.

[pt] O crescente uso de antenas para a transmissão de dados tem demandado a instalação de um número crescente de torres, com destaque para as torres estaiadas. Essas estruturas são compostas por um mastro central e diversos níveis de estais. As torres são estruturas esbeltas e apresentam um comportamento altamente não linear sob cargas estáticas e dinâmicas, devido à interação mastro-cabos e altura elevada da torre. O objetivo deste trabalho é estudar a influência da não linearidade no comportamento estático e dinâmico de uma torre estaiada. Para isto, desenvolvem-se modelos de torre estaiada em elementos finitos, com dois níveis de cabos pré-tensionados. Consideram-se dois tipos de geometria para a disposição dos cabos: em leque e em paralelo. Em particular, investiga-se o efeito da ruptura de um ou mais cabos e do comportamento elastoplástico dos materiais que compõem a torre estaiada na estabilidade e vibrações não lineares da estrutura. Inicialmente, avalia-se o comportamento linear da estrutura, obtendo-se as frequências naturais e cargas críticas. A seguir, obtêm-se os caminhos não lineares de equilíbrio de cada modelo, aplicando o conceito de imperfeição modal. Finalmente, realiza-se a análise da vibração livres e forçada amortecida. Para isto utilizam-se as respostas no tempo e plano de fase, transformadas de Fourier e espectrográficos. Em todos os casos analisa-se em detalhe o efeito da perda de cabos e da plastificação dos elementos na capacidade de carga, estabilidade e deslocamentos da estrutura. Os resultados demonstram que a perda de cabos e plastificação dos elementos têm grande influência nas frequências naturais e cargas críticas. Finalmente, nessas condições observa-se um comportamento não linear com perda de capacidade de carga e aumento significativo de deslocamentos, velocidades e acelerações, evidenciando a necessidade de investigação do comportamento não linear desse tipo de estrutura. / [en] The growing use of antennas for data transmission calls for the installation of growing number of high towers, with the cable-stayed towers standing out. These structures are composed of a central mast and several levels of stays. These towers are slender structures and exhibit a highly non-linear behavior under static and dynamic loads, due to the mast-cable interaction and the tower height. The objective of this work is to study the influence of the nonlinearity on the static and dynamic behavior of a cable-stayed tower. For this, finite element models of cable-stayed towers with two levels of pre-tensioned cables are developed. Two cable disposition geometries are considered: fan and parallel. In particular, the effect of the rupture of one or more cables and the elastoplastic behavior of the cable-stayed tower materials on the stability and non-linear vibrations of the structure is investigated. Initially, the linear behavior of the structure is evaluated through the natural frequencies and critical loads. Next, the non-linear equilibrium paths of each model are obtained, applying the concept of modal imperfection. Finally, free and forced damped vibration analysis is performed. For this purpose, responses in time and phase plane, Fourier transforms and spectrographs are used. In all cases, the effect of the loss of cables and the plastification of the elements on the load capacity, stability and displacements of the structure is analyzed in detail. The results demonstrate that the loss of cables and plastification of elements have a great influence on natural frequencies and critical loads. Under such conditions, non-linear behavior with loss of load capacity and significant increase in displacements, velocities and accelerations stand out, and highlight the need for investigation of the nonlinear behavior of this type of structure.