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An investigation of lubrication of knee joint replacement
Sýkora, Tomáš ; Horák, Zdeněk (referee) ; Nečas, David (advisor)
This diploma thesis deals with an experimental analysis of knee joint replacement lubrication. The experiments were realized at a knee joint simulator which can apply conditions according to certain standard and survey the phenomena by using fluorescence microscopy. The aim of thesis is to clarify the influence of particular components of synovial fluid on the lubrication process. The intensity of fluorescence expresses dimensionless parameter of a lubrication film thickness. There was a fundamental study with mineral oils before the experiments with the synovial fluid. The study allows to have a look at contact transformation during walk. Results are shown in graphs as dependency of intensity on time, including pictures showing phenomena in the contact zone. Experiment results show that protein -globulin creates a layer on the surface. There is albumin on the layer and it makes the lubricating film thicker. The protein interaction is supported by hyaluronic acid and fosfolipids which stabilizes the created structure. According to lubrication is behaviour of film related to a complex structure of synovial fluid. Thesis gives more information about behaviour of synovial fluid and can be used for future development of knee replacements.
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Development of the coefficient of friction and lubrication film in a total knee replacement during a gait cycle
Odehnal, Lukáš ; Horák, Zdeněk (referee) ; Ranuša, Matúš (advisor)
This master´s thesis deals with the experimental analysis of the coefficient of friction and lubrication film in total knee replacement. The experiments are performed on a knee joint simulator, with an implemented module for measuring friction. To observe film formation, fluorescent microscopy is used. The experiments are mainly focused on a detailed description of the influence of parameters occurring during the gait cycle. This approach should significantly help in describing the tribological processes that occur in the total knee replacement. The results confirm previous investigations in terms of axial load, where the coefficient of friction decreases with the increasing load. In the case of lubrication film, no significant changes are observed. On the contrary, while investigating the influence of SRR, noticeable changes in film formation are observed while the coefficient of friction being unaffected. While describing the whole gait cycle, precise results are obtained only in the first half of the cycle as the second half is accompanied by the occurrence of large deviations from a rapid decrease of load. This work provides a better understanding of the field of lubrication film in total knee replacements. Moreover, thanks to the simultaneous measurement of the coefficient of friction and the observation of the contact area, it is possible to draw better conclusions than if the experiments had been carried out separately.
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Influence of viscosupplementation on cartilage lubrication
Ondra, Martin ; Horák, Zdeněk (referee) ; Ranuša, Matúš (advisor)
This work deal with the determination of the effect of viscosupplementation on the lubrication of articular cartilage in the beginning phase of osteoarthritis. This effect was evaluated based on the development of CoF measured by a tribometer in configuration pin-on-plate. The tribological model of incipient osteoarthritis was simulated by using two articular cartilages lubricated with osteoarthritic synovial fluid to which viscosupplementation agents were added. These preparations differed mainly in cross-linking and molecular weight of hyaluronic acid (HA). Measurements have shown that viscosupplementation may be effective in the beginning phase of osteoarthritis. The efficacy of viscosupplementation preparations with cross-linking HA was significantly higher compared to the efficacy of viscosupplementation preparations without cross-linking. These results support the use of viscosupplementation to delay the advanced stage of osteoarthritis.
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Internet Used-Cars Shop
Horák, Zdeněk ; Jurka, Pavel (referee) ; Skřivánek, Roman (advisor)
This bachelor's thesis contains the analysis, the design and the information system implementation of the Internet used-cars shop. The system files predominantly information about the cars which the used-cars shop offers for sale. The system saves basic data about each car, the data about the former keeper, general information about the car producer and about the car price changes. Two kinds of users can log into the system with a specific password. The customer of the used-cars shop who is allowed to view the catalogue of offered cars and make a reservation. The second is the system administrator who can edit saved data. The used-cars shop forum is also available.
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Lubrication of knee joint replacement
Sadecká, Kateřina ; Horák, Zdeněk (referee) ; Vrbka, Martin (advisor)
The work deals with the lubrication of total knee replacement using fluorescence microscopy method, which allows unique insight into the contact between femoral and tibial component. The aim was to determine the effect of composition of synovial fluid (i.e. albumin, -globulin, hyaluronic acid and phospholipids) on film thickness and protein behaviour in contact, and also to determine changes of contact area during rotation. Since this is the first experimental work dealing with a knee replacement lubrication primarily, only simple rotation and load cycles were applied by the knee simulator. The output of the experiments was fluorescence intensity, which corresponds to dimensionless film thickness, over time. Another important output are the images directly showing the fluorescently labelled proteins in the contact area. The results show, there are fundamental differences in lubrication in different positions of rotation, due to changes of position, shape and behaviour of the contact area. The composition of the lubricant is also essential, since the proteins themselves form a relatively strong lubricating film and their mixture leads to a substantial reduction of film thickness, due to significant formation of clusters. Complex fluid, although it does not form the strongest layer, is able to create a quite continuous film.
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Information System Assessment and Proposal of ICT Modification
Horák, Zdeněk ; Ing.Jiří Hájek (referee) ; Koch, Miloš (advisor)
This graduation theses treats of the system for return mechandise authorization processing for the organization Digilive s.r.o. The system should improve and modernize work of the employees and the clients in the process of attending the sales return. The system will contain two kinds of the users. The client can make sales returns and view data about his sales returns. The employee can edit all data about the sales returns and the clients. The employee segment is implemented with the 5-dimension model access data.
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Supportless 3D print by 6-axis robotic arm
Krejčiřík, Petr ; Horák, Zdeněk (referee) ; Škaroupka, David (advisor)
This diploma thesis deals with the solution 3D printing by KUKA robotic arm without realization of supporting structures. The 6-axis KUKA KR 60HA robotic arm allows adjusting 3D printing strategies compared to classical 3D printing concept. The first part of the diploma thesis is about the identification of the current state of knowledge, especially the state of the experimental device for the robotic 3D print. To improve quality of the printed is necessary to modify the printing head and develop the suitable calibration principle. Special printing strategies were designed to rearch the 3D printing overhead volumes without creating support structure. A special alghoritm in the Grasshopper evnironment was developed for generating 3D print trajectory on the body surface. For the quality improvement it is necessary to optimize the process parameters. The final step is experimental 3D printing with the evaluation of surface dimensions, geometric precision and layer coherence in various printing strategies.
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Variants of Financing the Acquisition of Fixed Assets
Horák, Tomáš ; Horák, Zdeněk (referee) ; Fedorová, Anna (advisor)
The bachelor thesis discusses the possibilities of financing the acquisition of fixed assets in the company. In the section of theory it is in detail analysed the various concepts on the topic of fixed assets financing. The following practical part, where there is determined the financial situation of company, based on financial analysis, compares an alternatives of the fixed assets financing in regards to the current market conditions. Finally, there is communitated the recommended alternative of financing.
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The effect of climate conditions on wheel-rail contact adhesion
Nohel, Rostislav ; Horák, Zdeněk (referee) ; Omasta, Milan (advisor)
Presented master’s thesis is focused on the experimental research of influence of climate conditions on wheel-rail adhesion, where climate conditions are meant two parameters: ambient air temperature and air humidity. These parameters always affect wheel-raid contact and their values change significantly during the year. For presented experimental research was used tribometer Mini Traction Machine (MTM) in configuration „ball on disc“. For determination of influence climate conditions was first found out the influence of air humidity on adhesion at certain temperatures, which varied between (1 to 50) °C. These experiments were performed for two types of discs, where one disc was exposed to leaf extract contamination. After that was assembled influence of both parameters (air humidity and ambient air temperature) on adhesion in the form of a 3D map, where were distinctioned states, when condensation has occured and when didn‘t. Obtained results in this thesis will be used for optimalization of rail vehicle control systems.
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Kinematic analysis of children's gait
Kernerová, Helena ; Vilímek, Miloslav (advisor) ; Horák, Zdeněk (referee)
Title: Children's gait characteristics and kinematic analysis Objectives: The aim of the master thesis is to perform an analysis of the gait of children engaged in intensive sports training (floorball) and children who are not intensively engaged in sports, and to compare selected spatio-temporal, kinetic and kinematic parameters of these two groups. Methods: The work has a theoretical-empirical nature with a smaller number of probands. 3D kinematic analysis of gait was recorded with a Qualisys device and reaction forces from the pad with 7 Kistler force plates. The following parameters are monitored in the thesis: step length, step speed depending on height, range of plantar and dorsiflexion in the ankle joint, rotation of the pelvis and shoulders in the transverse plane, vertical and anterior-posterior component of reaction forces from the ground. Results: The results of the study showed that for some kinematic parameters, intensive sports training of children aged 7-13 years leads to changes in the behavior of individual analyzed parameters. This is mainly due to the fact that the tested group has more symmetrical rotation of the pelvis and shoulders in the transverse plane compared to the control group. However, the results obtained in terms of statistical probability are not sufficiently...
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