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Measurement of viscosity of suspensions during wheat bran processing
Koukal, Jan ; Slavíková, Zuzana (referee) ; Pořízka, Jaromír (advisor)
This bachelor thesis deals with the assessment of the viscosity evolution of wheat bran suspension during alkaline hydrolysis. Wheat bran is a widely produced low-cost by-product of the milling industry. Due to its composition, bran is a suitable substrate for biorefining and involvement in the circular economy. However, during processing, viscosity development occurs, which greatly affects the energy requirements for processing. The temporal evolution of viscosity during alkaline hydrolysis was determined using a rotational rheometer at constant shear rate. Viscosity was assessed as a function of NaOH concentration, temperature and bran ration. Furthermore, the evolution of viscosity was measured during alkaline extraction of proteins. The highest viscosity was measured in a 0.2 M NaOH system at 30 °C with a bran to hydroxide ratio of 1:10. Its value was 0.991 ± 0.010 Pa.s. Based on the theoretical part and the data obtained from rheological measurements, the design of a stirred reactor for wheat bran processing on an industrial scale was carried out. It is a vertical cylindrical vessel with a total volume of 10 m3. The vessel is equipped with three Chemineer HE-3 hydrofoil impellers mounted on a vertical shaft. The power input of the agitator was calculated at 2.8 kW and compared to a conventional 4-blade, 45-degree pitched blade turbine, the chosen design was four times more efficient.
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Rheological properties of building binders in their fresh state
Hegrová, Michaela ; Rovnaník, Pavel (referee) ; Vyšvařil, Martin (advisor)
This thesis is devoted to the rheological properties of building binders. The theoretical part focuses on individual types of building binders, their rheological properties and basic parameters determinated during the rheological characterization of building binders. The practical part deals with the resultes obtained from the meansurements on a rotational rheometr using the geometry type of plate to plate. These results are subsequently evaluated.
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Composite medical textile - preparation, characterization, application
Bušinová, Zuzana ; Ing. Vítězslav Zilvar. (referee) ; Krouská, Jitka (advisor)
This bachelor thesis deals with the setting time of the Safix plus gypsum bandage from the Hartmann - Rico a.s. company. The aim of the work is to improve the quality control process of this product and developing a simple robust method for determining the quality control of the Safix plus plaster cast. Two methods and instruments were chosen for the measurement, the Vicat instrument and a rheometer. Vicat's device works on the principle of measuring the depth of penetration of the penetrating body into the sample from a constant height. A rheometer is used to measure rheological properties of the sample, such as viscosity. For both of these methods, it was necessary to prepare the gypsum powder from the gauze. By measuring on the rheometer, the setting time was determined to be 2.4 ± 0.1 minutes and by measuring on the Vicat instrument the observable setting time was determined to be 3.1 ± 0.2 minutes and the complete solidification time to be 6.0 ± 0.4 minutes. Due to the purchase price of the rheometer and in combination with the intended purpose (i.e., product quality control in the commercial sector), the use of a Vicat device appears to be a more suitable option, not only due to the considerably lower purchase price, but also due to simplicity of measurement.
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Hydrogels with carbon fibers
Kučerová, Barbora ; Bouška,, Marek (referee) ; Pekař, Miloslav (advisor)
This diploma thesis is focused on the study of the behaviour of carbon fibers in the hydrogel, especially the viscoelastic modules od these gels ort he coefficient of color transmission through the gel. The main goals were to optimize the samples and measure their viscoelastic modules on a rheometer, in several different modes. This was followed by simulation of physiological conditions for selected samples and their measurement on the rheometer. There was also an experiment of continuous diffusion in cuvettes, in which the penetration of the dye through the gel with the addition of fibers and for comparison also without them. Last but not least diffusion pairs were prepared.
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Measurement of viscosity of suspensions during wheat bran processing
Koukal, Jan ; Slavíková, Zuzana (referee) ; Pořízka, Jaromír (advisor)
This bachelor thesis deals with the assessment of the viscosity evolution of wheat bran suspension during alkaline hydrolysis. Wheat bran is a widely produced low-cost by-product of the milling industry. Due to its composition, bran is a suitable substrate for biorefining and involvement in the circular economy. However, during processing, viscosity development occurs, which greatly affects the energy requirements for processing. The temporal evolution of viscosity during alkaline hydrolysis was determined using a rotational rheometer at constant shear rate. Viscosity was assessed as a function of NaOH concentration, temperature and bran ration. Furthermore, the evolution of viscosity was measured during alkaline extraction of proteins. The highest viscosity was measured in a 0.2 M NaOH system at 30 °C with a bran to hydroxide ratio of 1:10. Its value was 0.991 ± 0.010 Pa.s. Based on the theoretical part and the data obtained from rheological measurements, the design of a stirred reactor for wheat bran processing on an industrial scale was carried out. It is a vertical cylindrical vessel with a total volume of 10 m3. The vessel is equipped with three Chemineer HE-3 hydrofoil impellers mounted on a vertical shaft. The power input of the agitator was calculated at 2.8 kW and compared to a conventional 4-blade, 45-degree pitched blade turbine, the chosen design was four times more efficient.
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Hydrogels with carbon fibers
Kučerová, Barbora ; Bouška,, Marek (referee) ; Pekař, Miloslav (advisor)
This diploma thesis is focused on the study of the behaviour of carbon fibers in the hydrogel, especially the viscoelastic modules od these gels ort he coefficient of color transmission through the gel. The main goals were to optimize the samples and measure their viscoelastic modules on a rheometer, in several different modes. This was followed by simulation of physiological conditions for selected samples and their measurement on the rheometer. There was also an experiment of continuous diffusion in cuvettes, in which the penetration of the dye through the gel with the addition of fibers and for comparison also without them. Last but not least diffusion pairs were prepared.
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Composite medical textile - preparation, characterization, application
Bušinová, Zuzana ; Ing. Vítězslav Zilvar. (referee) ; Krouská, Jitka (advisor)
This bachelor thesis deals with the setting time of the Safix plus gypsum bandage from the Hartmann - Rico a.s. company. The aim of the work is to improve the quality control process of this product and developing a simple robust method for determining the quality control of the Safix plus plaster cast. Two methods and instruments were chosen for the measurement, the Vicat instrument and a rheometer. Vicat's device works on the principle of measuring the depth of penetration of the penetrating body into the sample from a constant height. A rheometer is used to measure rheological properties of the sample, such as viscosity. For both of these methods, it was necessary to prepare the gypsum powder from the gauze. By measuring on the rheometer, the setting time was determined to be 2.4 ± 0.1 minutes and by measuring on the Vicat instrument the observable setting time was determined to be 3.1 ± 0.2 minutes and the complete solidification time to be 6.0 ± 0.4 minutes. Due to the purchase price of the rheometer and in combination with the intended purpose (i.e., product quality control in the commercial sector), the use of a Vicat device appears to be a more suitable option, not only due to the considerably lower purchase price, but also due to simplicity of measurement.
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Effects of rehabilitation methods on the course of knee osteoarthritis
Novák, Dalibor ; Barna, Miloš (advisor) ; Kučera, Miroslav (referee)
Knee osteoarthritis is the most often form of the progressive degenerative injury called osteoarthritis, which signifies the most widely extended knuckle disability all over the world. And so it turns into a serious healthy and social-economic problem. Besides the symptomatic treatment of pain, the effort of contemporary therapy is to affect those processes, which lead to osteoarthritis morphological progression. The medical treatment should be carried out preferably at total range and with rehabilitation as its integral part. This report sums up many till now published knowledge above knee osteoarthritis itself and above its treatment processes, primarily in case of use some rehabilitation methods, and offers some information above evaluation effect of therapeutical processes for course of this disorder. Powered by TCPDF (www.tcpdf.org)
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Rheological properties of building binders in their fresh state
Hegrová, Michaela ; Rovnaník, Pavel (referee) ; Vyšvařil, Martin (advisor)
This thesis is devoted to the rheological properties of building binders. The theoretical part focuses on individual types of building binders, their rheological properties and basic parameters determinated during the rheological characterization of building binders. The practical part deals with the resultes obtained from the meansurements on a rotational rheometr using the geometry type of plate to plate. These results are subsequently evaluated.
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Study of rheological properties of concrete with the addition of low-temperature plasma treated polymer fibers
Gromeš, Vít ; Herka, Petr (referee) ; Bodnárová, Lenka (advisor)
Polypropylene fibers are used in concrete mixtures to avoid early cracks during shrinkage. Low thickness of each fiber and low density are reasons, why these fibers are effective in small dosage. Their disadvantages are smooth surface and hydrophobic character of polypropylene, thus it is necessary to improve their surface for better spread during mixing and to reach needed adhesion between fibers and cement paste. In present time are using chemical solutions applied on surface of the fibers to provide better water absorption, but the trend is reducing of using chemicals in industry and this situation demands new technology. There is possible solution, polypropylene fibers treated by low-temperature plasma. This method was developer by cooperation Masaryk University in Brno with company KrampeHarex and Brno Universiry of Technology. The goal of this thesis is to bring comparison, of influence on rheology properties of fresh concrete, between admixed the fibers with applied chemical layer and low-temperature plasma treated polypropylene fibers.
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