Made available in DSpace on 2016-12-08T15:56:19Z (GMT). No. of bitstreams: 1 Ricardo Kirchhof Unfer.pdf: 99775 bytes, checksum: 27709fdea77151b3e21cfdaf92146d6e (MD5) Previous issue date: 2015-08-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The new contributions of present thesis are an alternative experimental waviness method and a new theoretical model for evaluation of limit strains of sheet metal forming in the automotive industry, employing the analysis of roughness and waviness parameters evolution with the equivalent plastic strain and a new ductile rupture criterion as function of stress triaxiality. For validation of proposed experimental waviness method and rupture criterion, specimens of IF steel sheet of thickness 0.72mm, 0.82mm and 0.85mm were tested under tensile test and Nakazima sheet forming test with Marciniak flat punch. The specimens were deformed in incremental steps in different strain path such as: balanced biaxial stretching, plane strain, uniaxial tension and pure shear. Present proposed method consider that roughness and waviness parameters are important surface quality index and useful as indicator of onset of visible local necking and should be monitored in sheet metal forming. Thus, a Waviness Limit Curve, WLC, is proposed to be plotted in Map of Principal Limit Strains (MDLC) of sheet metal as an alternative to the forming limit strain curve, FLC. Various parameters of roughness and waviness such as arithmetic average roughness (Ra), maximum peak-valley roughness (Rt), arithmetic average waviness (Wa), total heigth peak-valley waviness (Wt), maximum peak height waviness (Pp) and maximum valley depth waviness (Pv) were measured during the uniaxial and biaxial testing. Tensile test of IF steel specimens at 0º, 45º and 90º to the rolling direction, RD, and Nakazima type of IF steel specimens at 0º RD only, in which a mesh of 2.5mm circles were printed, were employed. During the uniaxial and biaxial testing, the following plastic deformations were calculated in each straining step from the printed circles in the sheet surface: major true strain (1) and minor true strain (2). Parameters of roughness and waviness versus equivalent plastic strain curves were plotted to obtain a phenomenological equation of 4th and 3rd degree polynomials, using the Hill 1979 yield stress criterion. Furthermore, the growth rate of parameters Wa and Wt with equivalent plastic strain were calculated. From the growth rate, it was possible to conclude that the sheet 12 thickness imperfections, measured by Wa and Wt, evolve during material deformation, being possible to predict with accuracy the influence of equivalent plastic strain in the onset of local necking. From the experimental analysis, it was concluded that the maximum peak-valley waviness parameter (Wt) was the best option to chacaracterized the beginning of local necking in IF steel sheet forming. Thus, from the analysis of waviness growth rate parameters, Wa and Wt, during plastic strains, it was possible to propose a criterion of local necking inception. This allowed to obtain and plot an experimental Waviness Limit Curve (WLC) in the map MDLC: the beginning of local necking was established when the normalized parameter Wt* (=Wt/Wto) attained a critical value Wt*= 2.5, but with distinct values of equivalent strains. A second mathematical model was proposed for local necking criterion to obtain the FLC of IF steel sheets, employing stress triaxiality analysis and the Hill 1979 yield stress criterion. 2nd degree polynomials were obtained from plotted and adjusted phenomenological curves in graphs of equivalent strain at rupture versus stress triaxiality, considering the different plastic strain path in the formability testing. The IF steel specimens showed ductile rupture, according to scanning electronic microscope examinations, which showed that rupture occurred due to formation, growth and coalescence of large quantity of pores in many specimens of balanced biaxial (BB) and plane strain (DP). Also, mixed rupture of ductile type due to shear mechanisms in certain regions of tensile test (TS) and Nakazima uniaxial tension (UTN) specimens were shown. / As propostas de ineditismo da presente tese foram mostrar um método experimental alternativo de rugosidades e um modelo teórico de ruptura novo para se avaliar as deformações limites de conformação de chapas metálicas da indústria automobilística, empregando-se uma análise da evolução dos parâmetros de ondulação da rugosidade com a deformação plástica equivalente e um critério de ruptura dúctil em função da triaxialidade das tensões. Para validação do método experimental de rugosidades e do critério de ruptura propostos, utilizou-se corpos de prova de chapas de aço IF de 0,72mm, 0,82mm e 0,85mm de espessura, que foram submetidas aos ensaios de tração simples e ensaio de estampagem tipo Nakazima com punção plano de Marciniak. As amostras foram sujeitas a deformação incremental em diferentes trajetórias de deformação, tais como: estiramento biaxial balanceado, deformação plana, estiramento uniaxial e cisalhamento puro. O presente método proposto considera que parâmetros de rugosidade e ondulação são índices importantes de qualidade da superfície e servem como indicador preciso do início da estricção local visível e devem ser monitorados na conformação de chapas metálicas. Portanto, propõe-se traçar uma Curva Limite de Ondulação da Rugosidade, CLOR, no Mapa das Deformações Principais Limite de Conformação (MDLC) das chapas metálicas como alternativa da curva limite de conformação, CLC. Vários parâmetros do perfil de rugosidade e da ondulação da rugosidade tais como a rugosidade média aritmética (Ra), altura máxima pico-vale (Rt), ondulação média aritmética (Wa), a altura máxima da ondulação pico-vale (Wt), altura máxima de pico da ondulação (Pp) e profundidade máxima de vale (Pv) foram medidos durante os ensaios uniaxiais e biaxiais. Foram utilizados corpos de prova de aço IF em tração simples a 0º, 45º e 90º da direção de laminação, DL, e corpos de prova tipo ensaio Nakazima de aço IF somente a 0º DL nos quais foram impressos uma malha de círculos de 2,5 mm de diâmetro. Durante os ensaios uniaxiais e 10 biaxiais, as seguintes deformações plásticas foram calculadas em cada etapa a partir da malha de circulos impressos na superficie da chapa: a deformação verdadeira longitudinal maior (1) e a deformação verdadeira transversal menor (2). Curvas dos parâmetros de rugosidade e ondulações versus deformação plástica equivalente, empregando-se o critério de escoamento plástico de Hill (1979), foram traçados para se obter equações fenomenológicas do tipo polinomial de 4° e 3° graus. Além disso, foram calculadas as taxas de crescimento dos parâmetros Wa e Wt com a deformação plástica equivalente. A partir das curvas de taxas crescimento, foi possível concluir que as imperfeições na espessura da chapa, medidas por meio de Wa e Wt, evoluem durante a deformação do material, sendo possível prever com precisão a influência da deformação plástica equivalente no início do surgimento da estricção local. Concluiu-se então que o parâmetro da altura máxima total pico-vale das ondulações (Wt) é a melhor opção para caracterizar o início da estricção local em chapas de aço IF. Portanto, a partir da análise das taxas de crescimento dos parâmetros de ondulação, Wa e Wt, durante as deformações plásticas, foi possível propor um critério para o surgimento da estricção local. Isto permitiu obter e traçar a curva experimental de Limite de Ondulação da Rugosidade, (CLOR), no Mapa MDLC: o início da estricção local foi quando o parâmetro normalizado Wt* (=Wt/Wto) atingiu o valor crítico Wt*=2,5, mas com valores distintos da deformação equivalente. Um segundo modelo matemático foi proposto como critério de estricção local para obtenção da CLC de chapas de aço IF, empregando-se análise da triaxialidade de tensões e o critério de escoamento plástico de Hill (1979). Foram obtidos polinômios de 2º grau por meio de curvas fenomenológicas ajustadas e traçadas nos gráficos de triaxialidade de tensões versus deformação equivalente de ruptura, considerando-se as diferentes trajetórias da deformação plástica dos ensaios de conformabilidade. As amostras de chapa de aço IF mostraram ruptura dúctil conforme exame no microscópio eletrônico de varredura, o qual mostra que a fratura ocorreu devido a formação, crescimento e coalescência de uma grande quantidade de espaços vazios ou poros na maioria dos corpos de prova tipo Biaxial Balanceado (BB) e Deformação Plana (DP). Também, as amostras apresentaram fraturas mistas do tipo dúcteis e com mecanismos de cisalhamento em determinadas regiões das amostras fraturadas em Tração Simples (TS) e Tração Uniaxial de Nakazima (UTN).

Submitted by LUIS HENRIQUE DE REZENDE CROZARIOL null (luiscrozariol@gmail.com) on 2017-09-26T22:06:47Z No. of bitstreams: 1 Dissertação Luis 26-09.pdf: 3642072 bytes, checksum: 6bd5d174cfe596f9dc2def41f1270185 (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-09-28T13:33:18Z (GMT) No. of bitstreams: 1 crozariol_lhr_me_ilha.pdf: 3642072 bytes, checksum: 6bd5d174cfe596f9dc2def41f1270185 (MD5) / Made available in DSpace on 2017-09-28T13:33:18Z (GMT). No. of bitstreams: 1 crozariol_lhr_me_ilha.pdf: 3642072 bytes, checksum: 6bd5d174cfe596f9dc2def41f1270185 (MD5) Previous issue date: 2017-07-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho é apresentada uma formulação do MEC (Método dos Elementos de Contorno) considerando-se não-linearidade física para analisar microestruturas de materiais heterogêneos no contexto da análise em multi-escala. A microestrutura, também denominada como EVR (Elemento de Volume Representativo), é modelada como uma chapa em sub-regiões onde vazios ou inclusões podem ser considerados dentro da matriz, sendo diferentes propriedades elásticas e modelos constitutivos definidos para cada sub-região. A equação integral para o deslocamento é obtida a partir do Teorema de Betti, onde para considerar o fenômeno dissipativo, um campo de esforços iniciais é considerado. A equação algébrica da chapa é obtida após a discretização do contorno externo e interface em elementos e do domínio das subregiões em células. Na análise multi-escala cada ponto da estrutura (macrocontínuo) é representado por um EVR, onde o comportamento do material não é definido por um modelo constitutivo, mas através da solução do problema de equilíbrio do EVR quando sujeito à deformação referente ao ponto do macrocontínuo. O problema de equilíbrio do EVR é definido em termos da flutuação dos deslocamentos, sendo o mesmo satisfeito quando seu campo de forças se encontra em equilíbrio. Após a solução do EVR, os deslocamentos no contorno e as forças dissipativas são atualizados e as forças de superfície sobre o contorno recalculadas para se obter a tensão homogeneizada. O custo computacional obtido com a presente formulação é menor que aquele referente ao modelo desenvolvido pelo Método dos Elementos Finitos, sendo a resposta homogeneizada do EVR comparada ao modelo de elementos finitos a fim de validar a formulação apresentada nesse trabalho. / A BEM formulation, considering dissipative phenomena, to analyze microstructures of heterogeneous materials in the context of multi-scale analysis is presented. The microstructure, also denoted as RVE (Representative Volume Element), is modelled as a zoned plate where voids or inclusions can be considered inside a matrix, being different elastic properties and constitutive models defined for each sub-region. The integral representation for displacement is obtained from Betti’s Theorem, where to consider the dissipative phenomena, an initial forces field is considered. The plate algebraic equation is obtained after discretizing the external boundary and interfaces into elements and the sub-regions domain into cells. In the multi-scale analysis, each macro-continuum point is represented by a RVE, being the material behaviour not governed by a phenomenological constitutive model, but defined after the solution of the RVE equilibrium problem due to the macro strain. The RVE equilibrium problem is defined in terms of displacement fluctuations, being satisfied when the forces field is in equilibrium. After the RVE solution, the boundary displacements and dissipative forces are updated and the boundary tractions recalculated to obtain the homogenized stress. The computational cost obtained with the proposed formulation is smaller than the formulation developed by the Finite Element Method. Besides, the homogenized response is compared to the finite element model to show its accuracy.

The subject of this thesis is spasticity in individuals with spinal lesions. The aim is to evaluate and compare a short-term effect of selected physio-therapeutic methods on spasticity of lower limbs in spinal patients. Two methods of comparison were chosen - passive stretching and the Vojta's reflex therapy. The work consists of two parts. The theoretical part describes the problems of spinal lesions, central motoneuron syndrome and spasticity, including its pathophysiology and investigation and therapeutic approaches. The practical part contains an attempt to verify and subsequently compare the immediate antispastic effect of the chosen methods, which is an important prerequisite for the following active exercises as an inseparable part of a physiotherapeutic exercise unit. Clinical evaluation scales are used to evaluate spasticity, namely Modified Ashworth Scale (MAS) and Muscle Excitability Scale (MES). The results are then compared with other studies and literature. Keywords spinal lesions, quadriplegia, Modified Ashworth Scale, Muscle Excitability Scale, Vojta's method, stretching

Objetivo: Exercícios de mobilização são aplicados em pacientes com Espondilite Anquilosante (EA) para preservar e restaurar a mobilidade axial, no entanto, não há descrição na literatura, de um programa específico de reabilitação compreendendo apenas exercícios de mobilização com e sem a associação de exercícios com resistência elástica em pacientes com EA. Assim, foram avaliados os efeitos de dois programas de exercícios quanto a mobilidade, capacidade funcional, qualidade de vida e atividade de doença em pacientes com EA. Métodos: Cinquenta e cinco pacientes com EA, sedentários, com Índice Bath de atividade de doença da Espondilite Anquilosante (BASDAI) < 4 foram incluídos no estudo. Os pacientes com EA foram alocados ao acaso em três grupos, um grupo foi prescrito exercícios de mobilização (M), um com o programa de mobilização mais exercícios de resistência elástica (M+R) e um grupo controle sem exercícios (C). As sessões de exercícios foram realizadas em grupos, duas vezes por semana, por 16 semanas, e todas as sessões foram supervisionadas. Os grupos M e M+R realizavam 30 minutos de alongamentos e exercícios de mobilidade para coluna, membros superiores e inferiores. Depois do programa de mobilização, apenas o grupo M+R realizava mais 30 minutos de exercícios com resistência elástica. A mobilidade, qualidade de vida, atividade de doença e parâmetros de atividade funcional foram avaliados no início do programa e depois de 16 semanas por um avaliador cego. Resultados: No início do estudo, a média de idade dos pacientes (DP) era 48,2 anos ( ± 11,7); tempo de doença 18,4( ± 9,9) anos; BASDAI 2,2( ± 1,2); escore global Bath de espondilite anquilosante (BAS-g) de 4,2( ± 2,3) Índice funcional Bath (BASFI) de 3,6( ± 2,4) e Índice de mobilidade Bath (BASMI) de 4,6( ± 2,1). Comparando valores iniciais e após 16 semanas o grupo M mostrou uma melhora significante no Índice BASMI e o grupo M+R apresentou uma melhora significante no BASMI e na expansibilidade torácica. BAS-g, BASDAI e BASMI foram significantemente piores no grupo C. Não houve diferença significante entre os grupos M e M+R, mas foi encontrada diferença estatisticamente significante entre os grupos C e M+R nos índices BASDAI, ASDAS e BASFI a favor do grupo M+R. Conclusão: Os programas de exercícios terapêuticos foram seguros e efetivos. O programa de mobilização promoveu benefícios apenas nos parâmetros de mobilidade articular. Os pacientes que realizaram programa de exercícios com resistência elástica além de apresentarem melhora na mobilidade articular, apresentaram melhora da atividade de doença e função quando comparado aos controles no fim do tratamento / Objective: Mobility exercises are used in Ankylosing Spondylitis (AS) patients to preserve and restore axial mobility, but there are no data regarding a specific rehabilitation program that includes mobility alone and its association with elastic resistance exercises in AS patients with stable disease activity. So, we assessed the effects of two exercise programs in terms of mobility, functional capacity, quality of life and disease activity in AS patients. Methods: Fifty-five sedentary AS patients with a Bath Ankylosing Spondylitis Activity Index (BASDAI) <4 were included. The AS patients were randomly assigned into three groups, to receive a mobility exercise program (M), or mobility plus elastic resistance exercise program (M+R) or no exercise (C). The exercises group sessions were conducted twice per week for 16 weeks. This supervised program comprised 30 minutes of outdoor stretching and mobility exercises for the spine and limbs (M). After the mobility program, M+R group carry out more 30 minutes of elastic resistance exercises. The mobility, disease activity and functional parameters were evaluated at baseline and after 16 weeks, with the evaluator blinded to the treatment group. Results: At study entry, the patients had a mean (SD) age of 48,2 years ( ± 11,7), disease duration of 18,4( ± 9,9) years, BASDAI 2,2( ± 1,2), Bath AS Global score (BAS-g) 4,2( ± 2,3) Bath AS functional Index (BASFI) of 3,6( ± 2,4) and Bath AS Metrology Index (BASMI) of 4,6( ± 2,1). Comparing the baseline to 16 weeks, group M showed a significant improvement in BASMI and M+R group showed significant improvement in BASMI and chest expansion. BAS-g, BASDAI and BASMI was significantly worst in C group. No significant differences between M+R group and M group were perceived but there were significant differences in BASDAI, ASDAS and BASFI scores between C group and M+R group in favor of M+R group. Conclusion: Therapeutic exercises programs were effective and safe. The mobility exercises program promoted benefits only in joint mobility parameters. The exercise program with elastic resistance besides those benefits for joint mobility, also improved function and disease activity comparing to controls at the end of the program

J'ai étudié expérimentalement, à l'échelle de la taille des particules, les mécanismes à l'origine de l'intensification des transferts ayant lieu dans les suspensions cisaillées de particules non-inertielles et non-Browniennes. Dans un premier temps, l'expérience de Taylor est revisitée en étudiant l'évolution d'une goutte de colorant soumise à un cisaillement périodique. Au-delà d'une amplitude critique de déformation, la présence des particules brise la réversibilité du système et induit une forte dispersion de la goutte de colorant. Ensuite, en m'intéressant au transfert en proche paroi, j'ai montré que la rotation des particules sur la paroi induit un transport à flux constant d'un scalaire jusque dans le bulk de la suspension, brisant la couche limite diffusive. Une solution analytique du profil de concentration dans cette zone est proposée, en bon accord avec les expériences. Finalement, des mesures PIV haute résolution du fluide interstitiel dans le bulk de la suspension ont été réalisées. A partir de ces champs de vitesses, on a reconstruit l'historique d'étirement de lignes matérielles du fluide et ainsi déterminé les lois d'étirement, information fondamentale pour la compréhension du processus de mélange. La présence des particules change les lois d'étirement qui passent de linéaires dans un fluide pur, à exponentielles en présence de particules. Un modèle d'étirements multiplicatifs est proposé, qui prédit quantitativement l'évolution de la moyenne, de la variance, et la forme log-normale des distributions d'étirements mesurées expérimentalement. L'inhomogénéité des étirements dans les suspensions cisaillées implique une large distribution du temps de mélange. / Mainly based on experiments, I investigated at a particle scale the mechanisms at the origin of the transfer enhancement in sheared non-Brownian and non-inertial particulate suspensions. First, I revisited Taylor's experiment, investigating the evolution of a drop of dye in a periodic shear. Beyond a critical strain amplitude, the presence of the particles breaks the reversibility of the system and the drop of dye is rapidly dispersed in the surrounding medium. Then, investigating the transfer process in the wall vicinity, I showed that in this region, the rotation of the particles convectively transport a scalar at a constant rate directly from the wall towards the bulk of the suspension, breaking the diffusive boundary layer. An analytical solution for the concentration profile in this region is proposed, in good agreement with experimental measurements. Lastly, high-resolution PIV measurements of the fluid phase were performed in the bulk of the suspension. Using these velocity fields, we reconstructed the stretching histories of fluid material lines to determine the stretching laws, crucial for the understanding of the mixing process. The presence of the particles changes the very nature of the stretching laws from linear, in a pure fluid, to exponential in the presence of particles. A multiplicative stretching model is proposed, which quantitatively predicts the experimentally measured evolution of the mean and the variance of the elongations of the fluid material lines as well as their evolution towards a log-normal distribution. The strong stretching inhomogeneity in sheared suspensions results in a broad distribution of the mixing time.

The main aim of this thesis is to introduce issue of averaging of biological signals. The first part of the thesis deals with the principles of individual averaging methods (constant, floating and exponential window) and describes their basic features. Moreover, the principle of filtered residue, detection of QRS complex, and stretching/shrinking the length of RR-interval to the standardized length are explicated. In the second part of the thesis the outcomes of practically realized (Matlab and GUI) methods of averaging (by final signal-to-noise ratio) are evaluated. Signals from MIT-BIH database are used.

The main objectives of this thesis are to study theory of signal averaging, filtered residue method and methods of stretching/shrinking signal. It will also test the functionality of those methods. Thesis contains theoretical analysis, explanation of principles and testing of behaving of used methods.

Les particules soumises à un écoulement peuvent manifester des orientations préférées et une variété de déformations en fonction de leur géométrie et élasticité et du champ de vitesse de l'écoulement. A l’inverse, les flux peuvent être modifiés lorsque les contraintes des particules sont non négligeables. Cette thèse présente des résultats théoriques et numériques sur cette relation bilatérale en deux parties. La Ière partie commence par une analyse de stabilité et des simulations numériques qui montrent une particule brownienne semi-flexible dans un écoulement élongationnel effectuant un retournement, un phénomène associé aux flux de cisaillement. Le Chap. 2 étend les outils analytiques dédiés aux modèles simples ou aux flux indépendante du temps pour les modèles perle-barre-bond généraux dans les flux aléatoires. En partant des résultats des chapitres précédents, Le Chap. 3 aboutit à l'étude d'un degré de liberté lagrangien inexploré dans un écoulement turbulent : la flexion. Une particule semi-flexible courbe différemment dans les flux aléatoires bidimensionnels et tridimensionnels. La IIème partie concerne la turbulence élastique, un régime chaotique créé dans un écoulement de faibles forces inertielles par l'ajout de polymères élastiques. Le Chap. 4 estime le nombre de degrés de liberté d'une solution de ce régime via la dimension Lyapunov de l'attracteur du modèle Oldroyd-B bidimensionnel, un modèle connu de reproduire la turbulence élastique dans les simulations numériques. Le Chap. 5 pose des questions sur la nécessité d'élasticité pour produire un régime chaotique et conclut qu'une solution de polymère de barres peut créer un régime comparable à la turbulence élastique. / Particles, when subjected into a flow, may display preferred orientations and a variety of deformations depending on their geometry and elasticity and the flow velocity field. Flows can conversely be modified when the particle stresses are sufficiently large. This thesis presents theoretical and numerical results on this two-way relationship between particles and flows in two parts. Part I starts with a stability analysis and numerical simulations that show a simple semiflexible Brownian particle in an extensional flow undergo tumbling, a phenomenon normally associated to shear flows. Chapter 2 extends analytical tools available only for elementary polymer models or for steady flows to general bead-rod-spring models in random flows. By building on the results from the previous chapters, Chap. 3 culminates with the study of an unexplored Lagrangian degree of freedom in a turbulent flow: bending. A semiflexible particle is shown to display different bending behaviours in two- and three-dimensional random flows. This prediction is confirmed via direct numerical simulations of the particle in a turbulent flow. Part II concerns “elastic turbulence", a chaotic regime created in a flow with low inertial forces by the addition of elastic polymers. Chapter 4 provides an estimate for the number of degrees of freedom of a solution of this chaotic system via the Lyapunov dimension of the attractor of the two-dimensional Oldroyd-B model, a model known to reproduce elastic turbulence in numerical simulations. Chapter 5 questions the necessity of elasticity in producing a chaotic regime and concludes that a rodlike polymer solution can create a regime similar to elastic turbulence.

I present an experimental study on the formation and dissociation characteristics of carbon dioxide (CO2) gas hydrates using Raman spectroscopy. The CO2 hydrates were formed from aqueous salt solutions with salinities ranging from 0-11 wt-%, and the salts used were sodium chloride (NaCl), potassium chloride (KCl), magnesium chloride (MgCl2) and calcium chloride (CaCl2). The experiments were conducted in a high-pressure vessel, in which the aqueous solution was pressurized with liquid CO2 to 6 MPa. First, I investigated how the addition of salts to a CO2-hydrate forming system inhibits the hydrate formation thermodynamically. For this purpose, the molar enthalpy of reaction between strongly and weakly hydrogen bonded water molecules was determined. I observed a decrease in the molar reaction enthalpy of up to 30 % for the highest salt concentration investigated. In addition, the influence of the salts on the solubility of CO2 in water was studied, which was reduced up to 40 %. The results showed that both properties could be well correlated with the effective mole fraction of salt in solution. Furthermore, the decrease in molar reaction enthalpy could be directly correlated with the equilibrium temperature of gas hydrates. This showed that the shift in equilibrium temperature induced by thermodynamic inhibitors was a direct result from the weakened hydrogen bonded network in the water-rich liquid phase before the onset of gas hydrate formation. Additionally, the growth mechanisms of CO2 hydrates were investigated by determining the amount of solid hydrate formed and the respective reaction constant. The reaction constant was not affected by the addition of salts, whereas the maximum amount of solid hydrate formed also showed a good correlation with the effective mole fraction. This finding leads to the assumption that salt does not affect the intrinsic growth mechanisms of hydrate formation, but that the weakened hydrogen bonded network leads to a decrease in the conversion of liquid water to hydrate and more water molecules stay in a liquid in the form of inclusions between the hydrate cages. Lastly, I analyzed the ratio of CO2 and water and the development of hydrogen bonds after the complete dissociation of hydrate. I observed a supersaturation of CO2 in the water-rich phase and found evidence that the excess CO2 exists as dispersed micro- or nanoscale liquid droplets in the liquid water-rich phase. The development of hydrogen bonds in the liquid water-rich phase was the same as before the hydrate formation. These results could be a possible explanation for the memory effect originating from residual nano- and mircodroplets. With this study, I aim to provide a better understanding of the mode of action of thermodynamic inhibitors and to contribute further insights to the controversially debated phenomenon of the memory effect.

A large proportion of patients with central motoneuron lesions is at risk of spastic paresis and formation of contractures. One of the therapeutic techniques used in patients with spastic paresis is prolonged stretching. The theoretical part summarizes the knowledge regarding spastic paresis, its clinical evaluation, the development of contractures and therapeutic interventions, especially botulinum toxin (BTX) and stretching. The aim of this study was to compare the effectiveness of prolonged stretching on spastic muscle contracture before and after BTX application. In our retrospective comparative study there were included 30 patients divided into two groups. The first group consisted of 15 patients performing prolonged stretching of the m. rectus femoris (m. RF) for three months according to Guided Self-rehabilitation Contract of Professor J. M. Gracies. The second group (15 patients) performing the same procedure, but at the same time BTX was injected into the m. RF. We monitored the change in passive knee joint range of motion into flexion and the change in 10MWT time. Statistical evaluation showed that the difference in knee joint range of motion after three months of performing prolonged stretching was statistically insignificant (p=0.194). The difference in knee joint range of motion after...