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...

This thesis work is part of an on-going project regarding load-bearing timber glass composites within the EU program WoodWisdom-Net. One major scope of that project is the adhesive material between the glass and timber parts. The underlying importance of the bonding material is related to the transfer of stress between the two materials – the influence of the adhesive stiffness and ductility on the possibility of obtaining uniform stress distributions. In this study the mechanical properties of two different adhesives are investigated, an epoxy (3M DP490) and an acrylate (SikaFast 5215). The differences of the adhesives lay in dissimilar stiffness, strength and viscous behaviour. In long term load caring design is important to understand the materials behavior under a constant load and a permanent displacement within the structure can cause major consequences. Therefore the main aim in this project is to identify the adhesives strength, deformation capacity and possible viscous (time dependent) effects. Because of the limitation of equipment and time this study is restricted to only three different experiments. Three different types of tensile tests have been conducted: monotonic, cyclic relaxation tests.The results of the experiments show that 3M DP490 has a higher strength and a smaller deformation capacity as compared to the SikaFast 5215. Thus, the SikaFast 5215 is more ductile. The 3M DP490 exhibits a lower loss of strength under constant strain (at relaxation). SikaFast 5215 showed also a large dependency of strain level on the stress loss in relaxation.

Abstract The effects of restoration and certain elements, nitrogen, sulphur, calcium and Misch metal, on the hot ductility of austenitic, high-alloyed austenitic and duplex stainless steels have been investigated by means of hot rolling, hot tensile, hot bending and stress relaxation tests. The results of these different testing methods indicated that hot rolling experiments using stepped specimens is the most effective way to investigate the relationship between the softening and cracking phenomena under hot rolling conditions. For as-cast, high-alloyed and duplex stainless steels with a low impurity level, the cracking tendency was observed to increase with increasing pass strain and temperature, being minimal for the small strain of 0.1. No cracking occurred in these steels when rolled in the wrought condition. It could be concluded that the cracking problems are only exhibited by the cast structure with the hot ductility of even partially recrystallised steel being perfectly adequate. However, the recrystallisation kinetics of the high-alloyed austenitic stainless steels, determined by stress relaxation and double-pass rolling tests, were found to be so slow that only partial softening can be expected to occur between roughing passes under normal rolling conditions. In the duplex steel, the restoration is fairly fast so that complete softening can occur within typical interpass times in hot rolling, while certain changes in the phase structure take place as well. Sulphur was found to be an extremely harmful element in duplex stainless steel with regard to their hot ductility so that severe cracking can take place with sulphur content above 30 ppm. However, the effect of sulphur can be eliminated by reducing its content and by calcium or Misch metal treatments that significantly increase the number and decrease the average size of the inclusions. It seems that the desulphurisation capacity of an element is the most important property for assessing its usefulness in reducing the detrimental influence of sulphur. The hot ductility of type 316L stainless steel determined by tensile tests was found to be better for nitrogen content of 0.05 wt-% than 0.02%, while in double-hit tensile tests the hot ductility values were identical. The mechanism whereby nitrogen affects hot ductility remains unclear but a retarding effect on static recrystallisation was observed.

1. Unterschiedliche Definitionen der Gesundheit mit verschiedenen Betrachtungsweisen (WHO: Der Mensch eine biopsychosoziale Einheit. Schulmedizin: ohne klinischen und paraklinischen Befund mit Orientierung an kritikbedürftigen Referenzmittelwerten) führt bei Fachleuten, Behörden und Laien zu Verwirrungen, wenn es um die Beurteilung gesundheitlicher Schäden geht. 2. Es wurde die Aufgabe gestellt zu prüfen, welche der beiden Definitionen der Realität näher kommt. 3. Mittels der chronopsychobiologischen Regulationsdiagnostik, des Dreiphasenentspannungstests (Hecht und Balzer 2001), wurden unter dem Aspekt der beiden Gesundheitsdefinitionen drei Gruppen untersucht (je 40 Probanden). - klinisch Gesunde (klinisch Gesunde nach Schulmedizin ) - Gesunde nach Definition der WHO - Probanden mit nichtorganische Insomnie (ohne pathologische klinische und paraklinische Befunde) 4. Die mit den verwendeten Methoden gewonnenen Daten wiesen aus, dass zwischen den klinisch Gesunden und den Probanden mit nichtorganischer Insomnie weitgehend größere Ähnlichkeiten bestehen. Beide Gruppen zeigten aber zu der Gruppe der Gesunden nach WHO-Definition, welche die biopsychosoziale Einheit des Menschen berücksichtigt, noch hochsignifikante Unterschiede. Die Gruppe der klinisch Gesunden kann daher auf Grund unserer Ergebnisse nicht den Anspruch erheben, real gesund zu sein. 5. Mit der Bezugnahme auf die Internationale Klassifikation der Krankheiten (ICD 10F) haben die von uns untersuchten klinisch Gesunden und die nichtorganischen Insomniker eine mehr oder weniger stark ausgeprägte Symptomatik von psychischen Störungen. Dies müsste bei der Beurteilung von Schadstoff-, Lärm-, und EMF-Wirkungen auf den Menschen, wie auch bei den klinisch-pharmakoloischen Untersuchungen beachtet werden. Die in der Arbeit erzielten Ergebnisse bedürfen durch weitere Untersuchungen eine Fundierung. Sie signalisieren aber sowohl unter praktischen als auch unter theoretischen Aspekten einen dringenden Forschungsbedarf. / 1. Differing definitions of health using different criterea (WHO: The human being as a bio- psycho-social unit versus classical medicine: without clinical and paraclinical results based on suspect reference values) bring confusion to experts, authorities and laymen when assessing health damages. 2. The given task was to check which of the two definitions is closer to reality. 3. Using the chrono-psycho-biological diagnostic of regulation, the three-phase-relaxation test (Hecht and Balzer 2001), three groups were examined considering the aspects of the two health definitions (40 test subjects in the study group). - clinically healthy (clinically healthy per classical medicine definition) - healthy per definition of the WHO - test persons with non organic insomnia (i.e. no pathological or paraclinical findings) 4. The data gained from the employed methods revealed bigger similarities between clinically healthy persons and those with non organic insomnia. Both groups still showed highly significant differences to the group which fulfils the definition of the WHO regarding a human as a bio-psycho-social unit. As a result of this study, persons, though classified as "clinically healthy" might nevertheless not absolutely be healthy in reality. 5. In reference to the international classification of illnesses (ICD 10 F) the groups examined, both of clinically healthy and those with non organic insomnia, have more or less severe psychological symptoms. This should be taken into account when assessing the effects of pollution, noise, and EMF as well as clinical pharmacological studies. These present findings still need broader confirmation by further investigations. However, they clearly indicate, for practical and theoretical considerations, an urgent need for further research.