Charles University in Prague, Faculty of Pharmacy in Hradci Králové Department of Pharmaceutical Technology Consultant: Mgr. Pavel Ondrejček, Ph.D. Student: Tomáš Marcinek Title of Thesis: The influence of the tableting speed on the compaction process The main aim of this thesis was to determine the influence of tableting speed on the compaction process of four substances. The compaction process was evaluated by three- exponential equation. The parameters of this equation describe the individual phases of compression, the precompression phase, the phase of elastic deformation and the phase of plastic deformation. Furthermore, the effect of tableting speed on the compressibility of the material was studied using the force-displacement record. Finally, the influence of tableting speed on tensile strength of the prepared tablets was evaluated. Four materials were used for the evaluation. Microcrystalline cellulose Avicel PH-102 and dicalcium phosphate dihydrate DI-CAFOS were used as model fillers. Theophylline and paracetamol were used as model drugs. The course of the compaction process was evaluated at five compaction speeds. The results of this evaluation revealed different behavior of used materials. Furthermore different influence on the compaction process by changing compaction speed was...

Charles University in Prague, Faculty of Pharmacy in Hradci Králové Department of: Department of Pharmaceutical Technology Consultant: Mgr. Pavel Ondrejček, Ph.D. Student: Nikola Marcinková Title of Thesis: The influence of the die size on the compaction process This diploma thesis is focused on exploration the influence of the die size on the compaction process. That was evaluated by parameters of three-exponential equation. Compressibility was studied by using force-displacement record. In this work was also observed an effect of die size on the tensile strength. In processing the experimental part of this work were used four different model materials. Microcrystalline cellulose and dicalcium phosphate are used as model fillers and theophylline and paracetamol as model active substances. Compaction of these materials was carried out in dies of size 7 mm, 9 mm, 11 mm, 13 mm and 15 mm. The results of the work showed that the die size significantly affects all parameters force-displacement record. With the growing size of the die there was a reduction of energy parameters. Most of the compaction parameters were statistically influenced. Increasing die size caused reducing volume reduction and energy consumption and increased speed of volume reduction at the stage of pre- compression and elastic...

Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Consultant: Mgr. Pavel Ondrejček, Ph.D. Student: Simona Berková Title of Thesis: The evaluation of compressibility of the mixtures pellets and microcrystalline cellulose This thesis is focused on the evaluation of powdered microcrystalline cellulose, pellets and mixtures thereof. Comprecel 102 was used as powdered microcrystalline cellulose. The used pellets were commercially available pellets Cellets 100 made of microcrystalline cellulose. The flow properties of used materials and their mixtures were evaluated by using the angle of repose, flow through orifice and Hausner ratio methods. Further the compressibility was evaluated using the force-displacement record. For the evaluation of compaction proces the three exponential compaction was used. Finally the radial tablet strength and tablet friability was tested. The results showed, that the flow properties improved with an increasing amount of pellets in mixture. I tis due to higher bulk and tapped density and also narrower particle size distribution, smoother surface and the regular shape of used pellets. The parameters of the force-displacement method showed different compressibility of used tabletting mixtures. The evaluation of...

Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical technology Consultant: Mgr. Petra Svačinová, Ph.D. Student: Michaela Přeučilová Title of Thesis: A comparison of viscoelastic properties of mixtures of lactose and different lubricants using the stress relaxation test This diploma thesis deals with viscoelastic properties of pharmaceutical excipients and tensile strength of tablets made of these excipients. Theoretical part is dedicated to description of lactose and lubricants, further the tablets compressibility and compression energy profile are described. The end of theoretical part deals with the stress relaxation test, with evaluation methods and the stress relaxation test influence on lactose tablets with different types of lubricants as well. The experimental part deals with the evaluation of the viscoelastic properties of two types of lactose and their mixtures with different types of lubricants at concentration of 1%. These characteristics were evaluated by stress relaxation test. All tablets were compressed by compression forces of 13 kN and 15 kN with dwell time 180 seconds. The study was about differences between two types of lactose, effect of lubricants and effect of two different compression forces on parameters of elasticity A1 -A3 and...

Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical technology Consultant: Mgr. Petra Svačinová, Ph.D. Student: Straková Markéta Title of Thesis: The influence of dwell time on the parameters of the stress relaxation test for lactose and calcium hydrogen phosphate The aim of this thesis is to find out viscoelastic properties of pharmaceutical excipients and to evaluate the tensile strength of tablets made of them. The theoretical part describes used materials, these are lactose, calcium hydrogen phosphate and magnesium stearate. The thesis also deals with the stress relaxation test, its evaluation and usage. Tensile strength, calculation and various factors that affect tensile strength are described in the text. The experimental part deals with viscoelastic properties of used materials and their mixtures with lubricant using the stress relaxation test. Different dwell times (60 s, 120 s, 180 s, 240 s, 300 s, 360 s, 420 s, 480 s, 540 s, 600 s) were used for individual measurements. The relation between elasticity parameters (A1, A2, A3) and plasticity parameters (P1, P2, P3) depending on the dwell time was investigated. As for calcium hydrogen phosphate, the dwell time 180 - 240 seconds was found as the most appropriate. As for lactose, the optimum dwell...

Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Consultant: Mgr. Pavel Ondrejček, Ph.D. Student: Žofie Trpělková Title: A study of a compaction process of microcrystalline cellulose pellets This work is aimed at the comparison of two types of microcrystalline cellulose (Comprecel 102 a Avicel PH-200) with two types of pellets made of microcrystalline cellulose (Cellets 100 a Cellets 200). Important properties for the compaction into tablets were analyzed in these materials. The particle size distribution, the content of moisture, the bulk and tapped density, the flowability, the angle of repose and the Hausner ratio were evaluated. Furthermore, the compaction process was described by using the force displacement method and the three-exponential equation. Finally, the radial strength and the friability of tablets prepared by using two different compaction forces were evaluated. The results proved that both types of pellets have much better flow properties than powdered microcrystalline celluloses. This is primarily caused by the narrow particle size distribution, higher bulk and tapped density and the significantly smoother surface of pellets. Better flow properties of the pellets also influenced the parameters of the force-displacement...

Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical technology Consultant: Mgr. Svačinová Petra, Ph.D. Student: Hamplová Kateřina Title of Thesis: The influence of the dwell time on the parameters of the stress relaxation test for microcrystalline cellulose and starch. This thesis is focused on the viscoelastic properties of pharmaceutical excipients and the tensile strength of tablets. The theoretical part describes used materials. Microcrystalline cellulose and starch were used as fillers and magnesium stearate at concentration of 1% was used as lubricant. The stress relaxation test and its evaluation and utilization not only in pharmacy is described as well as the tensile strength of tablets. The experimental part deals with the viscoelastic properties of used materials and their mixtures with lubricant. These properties were evaluated using the stress relaxation test. At maximum compression force of 10 kN the length of dwell time was changed (60 s, 120 s, 180 s, 240 s, 300 s, 360 s, 420 s, 480 s, 540 s, 600 s). For derived parameters of elasticity A1-3 and plasticity P1-3 the dependence on the length of dwell time was evaluated. Parameter A1 increases with increasing dwell time for all substances. For parameters A2, A3, the dependence on the dwell...

La technique Imagerie par Contraste de Canalisation d’Électrons (ECCI) est utilisée dans le Microscope Électronique à Balayage (MEB) pour contraster et caractériser les défauts cristallins, tels que les dislocations. Ces dernières génèrent, en effet, différents contrastes selon l’orientation du faisceau incident par rapport aux plans cristallins {hkl} : dislocation brillante ou noir/ blanc sur un fonde sombre, dislocation noir sur un fond clair…Des modèles théoriques, basés sur la théorie dynamique de la diffraction, ont d’abord été, développés afin de décrire les contrastes produit d’un cristal parfait. Ensuite, ils ont été étendus au cas d’un cristal imparfait. Néanmoins, ces modèles théoriques ne proposent aucun calcul détaillé et aucune expression analytique. Dans cette thèse, nous développons une approche théorique originale pour modéliser les profils d’intensité BSE dans un cristal contenant des dislocations parallèles à la surface. Dans ce sens, nous proposons une modélisation pour différentes conditions de diffraction. Dans un deuxième temps, pour comprendre les mécanismes de formation des images ECC des dislocations, nous confrontons nos résultats expérimentaux aux profils théoriques obtenus. Finalement, nous présentons une nouvelle approche afin de comprendre les mécanismes de déformation des matériaux au voisinage des interfaces. Cette méthodologie consiste à caractériser les zones d’intérêts par ECCI avant et après avoir introduit localement une déformation plastique par nanoindentation. Ici, nous nous concentrons sur le cas d’un alliage à base de TiAl. / The Electron Channeling Contrast Imaging (ECCI) is a Scanning Electron Microscope (SEM) technique used to contrast and characterize crystalline defects, such as dislocations. These latter generate, in fact, different contrasts according to the orientation of the incident beam with respect to the crystalline planes {hkl}: bright or black/white on a dark background, black on bright background…Theoretical models, based on dynamical diffraction theory, were first developed to describe the contrasts produced by a perfect crystal. Then, they were extended to the case of an imperfect crystal. Nevertheless, such theoretical models do not propose any detailed calculation and any analytical expression. In this thesis, we develop an original theoretical approach for modelling BSE intensity profiles in a crystal containing dislocations parallel to the surface. In this sense, we propose modelling for different diffraction conditions. Secondly, in order to understand the mechanisms of the formation of dislocation ECC images, we confront our experimental results with the obtained theoretical profiles. Finally, we propose a new approach for understanding the deformation mechanisms of materials near interfaces. This methodology consists in characterizing the areas of interest by ECCI before and after introducing, locally, the plastic deformation by nanoindentation. Here, we focus on the case of a TiAl bases alloy.

Este trabalho apresenta um método para o reconhecimento e a detecção automática dos diferentes valores ou graus de deformação plástica em Ensaios Não Destrutivos empregando o Ruído Magnético de Barkhausen. O método é baseado no uso de uma Rede Neural Probabilística que permite o diagnóstico automático dos diferentes valores de deformação plástica, conteúdo de carbono, estas medidas são procedentes das medições das amostras de placas de aço AISI 1006, 1050 e 1070, esta base de dados foi feita pelo grupo de pesquisadores do Laboratório de Dinâmica e Instrumentação LADIN da Escola Politécnica da USP, departamento da Mecânica. Os excelentes resultados da rede neural probabilística de detectar automaticamente os valores de deformação mostram a efetividade do desempenho da rede neural probabilística que tem um desempenho superior aos métodos não destrutivos tradicionais e que realmente esta nova tecnologia é uma excelente solução para o diagnóstico. / This work presents a method for automatic detection and recognition of different levels or degrees of plastic deformation in Non-Destructive Testing using the Magnetic Barkhausen Noise. The method is based on using a Probabilistic Neural Network that allows the automatic diagnosis of the different values of plastic deformation and carbon content. The measurements corresponds to samples of steel plates AISI 1006, 1050 and 1070, this database was made by the group of researchers from the Laboratory of Dynamics and Instrumentation LADIN the Polytechnic School of USP, Department of Mechanical Engineering. The results show the effectiveness of the probabilistic neural network to automatically detect plastic deformation levels as well as carbon content level. This method has a superior performance in comparison to traditional nondestructive methods.

Neste trabalho se estuda a aplicação de um método de Ensaio Não Destrutivo, baseado no Ruído Magnético de Barkhausen (RMB), na medição de falhas superficiais em aços. O RMB é gerado por abruptas mudanças na magnetização de materiais quando submetidos a campos magnéticos variáveis. Essas mudanças são afetadas pela microestrutura e a presença e distribuição de tensões elásticas (compressão e tração). Inicialmente apresenta-se um estudo de medições de tensões produzidas por flexão, e perfis de dureza, via RMB. Analisa-se a influência de parâmetros de medição e analise dos sinais, na qualidade do diagnostico. Analisou-se a sensibilidade dos sinais de RMB na medição de tensão a parâmetros tais como direção de laminação da chapa, intensidade e frequência de campo magnético de excitação. Nos estudos da aplicação do RMB em medições de dureza, se usaram amostras de ensaio Jominy, com variação contínua de dureza. Utilizou-se dois tipos de materiais e foram feitas medidas de dureza HRC, RMB e análise metalográfica. O comportamento de diferentes parâmetros dos sinais de RMB se correlacionou com as medições de Dureza e as micrografias obtidas. As amplitudes do RMB mostraram ser inversamente proporcionais aos níveis de dureza. Também se apresenta uma nova tecnologia para inspeção de superfícies, baseado no conceito do Barkhausen Contínuo. São apresentadas análises de parâmetros de medição e de configuração de sonda, na inspeção sob três situações: presença de defeitos volumétricos, deformação plástica, e tensões mecânicas aplicadas. Estudou-se a influência de parâmetros como, amplitude do campo aplicado, velocidade de varredura, posicionamento e características do sensor, no nível de detecção do dano. Métodos de processamento de sinais específicos foram desenvolvidos. Os resultados mostraram, que para cada um dos casos estudados, é possível detectar a posição e nível do dano produzido. Essa nova tecnologia aumenta o espectro de soluções de Ensaios Não Destrutivos para problemas não contemplados pelos métodos existentes. / This work studies the application of a non-destructive testing method, based on the Magnetic Barkhausen Noise (MBN). MBN is generated by abrupt changes in magnetization of ferromagnetic materials subjected to variable magnetic fields. These changes are affected by the presence and distribution of elastic stresses (compression and traction) in the material and by its microstructure. At first, the present study describes MBN measurements of stresses produced by bending and MBN measurements of hardness profiles, in steel samples. The influence of both, measurement parameters and signal analysis, in the quality of fault diagnosis is also analysed. In this context, regarding stress measurements, the MBN signal sensitivity to parameters like surface lamination direction, intensity and frequency of magnetic excitation field is studied. On the other hand, application of MBN to hardness measurements used Jominy essay samples presenting continuous hardness variation. In this case, samples of two different materials were employed and hardness measurements were obtained by HRC, MBN as well as by metallographic analysis techniques. Behaviour of different MBN signal parameters were correlated with obtained hardness measurements and micrography. MBN amplitudes were shown to be inversely proportional to hardness levels. Finally, the work describes a new surface inspection technology, based on the concept of Continuous Barkhausen. In this context, the study analyses probe configuration and measurement parameters, concerning inspection of surface fault from three different origins: volumetric, plastic deformation, applied mechanical stress. The influence of parameters like applied field amplitude, probe velocity, sensor position and characteristics, in detecting damage level was also evaluated. In particular, specific signal processing methods were developed. Results showed that, for each studied case, it is possible to detect damage position and level. This new technology increases the range of NDT essay solutions for problems not yet contemplated by existing methods.