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Determining the compression behaviour of microcrystalline celluloses.
Coufal, Libor ; Špaček, Vladimír (referee) ; Řehula, Milan (advisor)
Coufal Libor, diploma paper, June 2009 Tablets are a very expanded dosage form. All new investigation in their technology are worth. While in pharmacopoeial method of measurement of mechanical strength of tablets evaluate by means of the strength at which the tablet breaks. This paper is based on the strength - course record. From this record, it is possible to ascertain other parameters of crushing process, such as the course of crushing, the crushing force and deformation energy. The radial strength, the volume deformation energy and deformation energy related to tablet weight are calculated from them. Tablets prepare from microcrystalline celluloses, hydroxyehylcelulose, powdered lactose monohydrate and substance called PharmDry (maltodextrine) were evaluated by means of these parameters. Results of this thesis shows descent of tensile strength in this order: microcrystalline cellulose Avicel PH-200, microcrystalline cellulose Avicel PH-102, maltodextrine, hydroxyethylcellulose and powdered lactose monohydrate. Kinetic characteristics of tablets descent in this order: microcrystalline cellulose Avicel PH-102, hydroxyethylcellulose, maltodextrine, microcrystalline cellulose Avicel PH-200 and powdered lactose monohydrate. Key words: strength - course record, course of crushing, crushing force,...
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Determining the compression behaviour of microcrystalline cellulose and aluminium stearate
Skopalová, Gabriela ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
This graduation theses delas with determination of compactibility of microcrystalline cellulose and aluminium stearate and their viscoelastic properties during the tablet formation. The force-distance record was used. The theoretical part concerns with characterization of microcrystalline cellulose and aluminium stearate and describes individual evaluation procedures and the influence of single materials to elastic recovery. The aim of experimental part was the determination of compaction pressure to compaction energy, compaction pressure to tablet relaxation and aluminium stearate concentration to compaction energy. Tablets were compacted in the T1 FRO machine, the preload was 2N, speed of preload 2mm/s and cycle rate 2mm/s.
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Viscoelastic properties of microcrystalline cellulose and lactose
Sosvorová, Lucie ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
The aim of this work was to evaluate the use of creep test during the compaction of microcrystalline celluloce Avicel PH 102, lactose FlowLac 100 and their mixtures in rates of 75:25, 50:50 and 25:75. Individual substances or mixtures were compressed by compression forces 0,25; 0,5; 1; 2; 3; 4; 5; 7,5; 10 and 15 kN. After the compression of each tablet a report describing the process of compression was procured. These dates were obtained by software connected with compression machine. Obtained relation bethween displacement and time was transfered to the relation bethween parameter J (creep compliance) and time. This relation was finally characterized by four basic parameters: E1 (immediate elasticity), E2 (retardet elasticity), P1 (plasticity) and FP (factor of plasticity). From the results we can see that microcrystalline celluloce Avicel PH 102 compared to lactose FlowLac 100 has lower elasticity and higher plasticity. With the decreasing value of microcrystalline celluloce Avicel PH 102 in the mixture the elasticity is inceased and plasticity decreased. Further was proved, that creep test method is usable in praxis for evaluation of pharmaceutical supplementary substances (fillers) used in the tablet manufacture. This test clearly valued the elasticity and plasticity by way of concrete numerical...
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Viscoelastic properties of microcrystalline cellulose of Avicel PH 200
Skálová, Marie ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
In this dissertation the viscoelasticity of the most common excipient microcrystaline celulose was valuated and viscoelasticite parametres were compared to three substances. Viscoelasticity was valuated by two methods..The first method is Creep test. In this analyze the compression force is constant and hold for 180s. During this time height of the tablet was lowered. The diffrences of tablet height was noted and used for calculation in Crčel test. Parameters of elasticity got by this method are FCT1,FCT2 and parameters of plasticity are PCT1,FP. When the parameters of elasticity increase the elasticity decrease. When the parameter FP increases the plasticity increases too. The higher the value of PCT1 is the lower is the plasticity. Stress relaxation is the second method. In this analyze hight of tablet is constant and decline compression force is recorded. In this analyze we noted the decline for 180 sec. In this way we get parameters of elasticity ESR1, ESR2, ESR3 and parameters of plasticity PSR1, PSR2, PSR3. The plasticity increases when parameter P increases. Comparing three substances the elasticity increases in-line Emcompress, Avicel, Flowlac and the elasticity decreases in-line Emcompress, Avicel, Flowlac.
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Viscoelastic properties of calcium hydrogenphosphate dihydrate of Emcopress
Hořínková, Pavla ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
The important condition for materials compression are their viscoelastic properties. Two methods are used in this work for determination viscoelastic parameters of calcium hydrogephosphate dihydrate - the Creep test and the Stress relaxation test. Both methods provide us with elastic and plastic constants. During the Creep test the compaction pressure is kept constant for 180s and a decrease of tablet height is measured. This tablet decreasing allows us to calculate viscoelastic parameters. The most important result is the factor of total plasticity FPC, which is equal to 0,89441. The greater this value is the better compaction properties the material has. A constant height of tablet is held for 180s in the Stress relaxation test and a decrease of pressure within the tablet is recorded. This pressure decrease is caused by three different processes. The third process is most important for the tablet plasticity and is expressed by the total parameter of third process PSR3C = 328,86916 MPas. Again, the greater this value is the better compaction properties the material has.
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Calculation of elasticity and plasticity of microcrystalline cellulose Avicel PH 103
Reich, Filip ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
Calculation of Elasticity and Plasticity of Microcrystalline Cellulose Avicel® PH - 103 Mgr. Filip Reich, Hradec Králové 2008 Avicel® PH - 103, well-known type of microcrystalline cellulose, is an important pharmaceutical excipient. Solid technological forms use to contain Avicel for its ability to reduce addition amount of pharmaceutical powders, tablets especially. Avicel also facilitates tableting of pressing power, this fact is important for therapeutical agents, that are sensitive for high pressure. The aim of this work was the definition and calculation of elasticity and plasticity of microcrystalline cellulose Avicel® PH - 103. The plasticity was determined from the "force - time" profile with three different methods. The first one was based on the proportion of the highest and the lowest pressing force. The second one used "one - parameter" evaluation of the "force - time" profile and the last one was established by using "three - parameter" rate. Further we had to determine Young's modulus, the elasticity character of system. The value equals 100,75023 MPa. From the "plasticity - force" profile we were able to distinguish the all compression phases with eventual progressing changes. Exactly there was the phase of precompression followed by the elastic and then the plastic deformation. This...
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Viscoelastic properties of lactose Flow Lacu 100
Patočková, Simona ; Řehula, Milan (advisor) ; Špaček, Vladimír (referee)
The aim of this work was to obtain viscoelastic charakteristics of one of the most used auxiliary pharmaceutical material. The testing material was lactose Flow Lac 100. Its viscoelastic properties were valued by two tests: Creep test and test Stress relaxation. Plastic properties are necessary to ensure good compressibility of material, whereas elastic properties can make difficulties during a compaction. In the theoretic part I dealt with energy of a tablet compaction. Elastic and plastic energy is acquired from measurement force - displacement, which represents continuance of a compaction process. The process of compaction can be classify into three parts according to the energy consumption: E1 is energy needed to prepressing, E2 is energy used for tablet forming and E3 means energy released from the tablet after compacting. Creep test: tablets were compressed to the defined compacting pressure and this pressure was held constant for a period of 180 s. In process of this period changes in height of a tablet was recorded. The decreasing height of the tablet was used for a determination of parameters of plasticity and elasticity: ECT1C = 72,1235 [s], ECT2C = 0,0117 [s], PCT1C =1,0623.107 [MPa.s], FPCTC =0,4828. Stress relaxation test: tablets were compressed to the defined compaction pressure and...
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Container trailer
Šálek, Pavel ; Špaček, Vladimír (referee) ; Kašpárek, Jaroslav (advisor)
This thesis deals with the design of a container carrier with interchangeable superstructures up to 3000 kg of technical weight. The introduction renders a critical review of similar devices and consecutive review of the device in terms of legislative matters. A dynamic simulation was used to calculate the loaded states. The outcome of the simulation was used to set the border conditions, which were then used for strength analysis calculations using finite element method (FEM). Blueprints of the final design are a part of the thesis.
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Competencies in Teacher Profession
ŠPAČEK, Vladimír
Definition of competences in teacher profession is still open question to be answered. Till today there is no common agreement about definition of competences as a term. There were elaborated many detailed studies about what do profession competences of teacher include, how to work with them in order to develop and deepen them. The aim of this thesis is to find characteristics of teacher, his competences expected from students and reputation of teacher profession in students´ eyes. In the theoretical part of this thesis is described profession of teacher, its´ phases, feminization, reputation, necessity and the whole Czech educational system in general. Furthermore we focus on personality of teacher, its´ identification, personality features, abilities, creativity and characteristics of teacher. In the final section of theoretical part there are described competences of teacher in general and mentioned the most often used classification of profession competences in teacher profession. The practical part of thesis is based on questionnaire examination from high school and college students. The questionnaire itself is focused on identifying of reputation of teacher profession among students and also on characteristics teacher should / should not have. Furthermore there are described teachers´ competences which are preferred / are not preferred from students.
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Research and Development Policy in the EU
Lepičová, Lenka ; Jakš, Jaroslav (advisor) ; Špaček, Vladimír (referee)
Práce informuje o vývoji, financování a tvorbě vědecko-výzkumné politiky EU. Je zde poskytnuta analýza stavu vědy a výzkumu v členských státech EU a provedeno porovnání s USA a Japonskem. Pozornost je věnována velice diskutovaným problémům jako jsou Patent Společenství a vznikající Evropský technologický institut. Dále je zhodnoceno zapojení do 6. rámcového programu v jednotlivých státech EU a komparace mezi těmito státy.
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