|
|
Corrosion degradation of magnesium alloys in SBF solutions
Ročňáková, Ivana ; Horynová, Miroslava (referee) ; Doležalová Weissmannová, Helena (advisor)
Nowadays, magnesium alloys are used in many sectors of human activity, particularly in the aerospace and automotive industries, due to a combination of good mechanical properties and low density of magnesium. Recently, however, the attention is paid to the possibility of using magnesium alloys in the medical field, mainly due to the chemical properties of magnesium. The diploma thesis is focused on evaluating of the corrosion behavior of AZ31alloy and AZ61 alloys in SBF solutions that are solutions simulating body fluids. The alloys were subjected to immersion test in Hank’s solutions for time span from 24 to 1008 hours. The corrosion process was evaluated based on several factors: alloy composition, time and pH changes. The thesis also describes in detail the methodology for establishing magnesium and zinc by method of flame absorption spektrometry (F AAS). The determination of aluminum was carried out by atomic absorption spectrometry with electrothermal atomization (ET AAS).
|
|
|
Methods of control of railway wheels in current technical practice
Ondriašová, Patricie ; Ročňáková, Ivana (referee) ; Juliš, Martin (advisor)
The proposed bachelor´s thesis looks into the inspection methods of railway wheelsets in current technical practice. First there is a description of the railway wheelset and the wheel production procedure. The main part of the thesis describes particular categories of wheel inspection. These are described as destructive, non-destructive and final tests. At the end some cases of wheel failure that happened during operation are stated. Finally there is also an outlook for railway transport in the future.
|
|
|
Polymers for health care and medicine
Jahodová, Daniela ; Ročňáková, Ivana (referee) ; Němec, Karel (advisor)
This bachelor thesis discusses polymers that are used in medicine and healthcare. In general, it addresses the field’s already known products and their possible further research and spreading of their use. Most people imagine medical polymer applications mainly in the forms of syringes, catheters, latex gloves, and the like. This text’s goal is to point out how much potential there is in further research of the material allowing for qualities as varied as biodegradable pill coating and high resistant dental implant.
|
|
|
Applications of magnesium alloys
Köhler, Tomáš ; Ročňáková, Ivana (referee) ; Němec, Karel (advisor)
This bachelor thesis includes basic knowledge of magnesium and its alloys. It also deals with their properties, division, and possibilities of heat treatment. The thesis then summarizes the application of magnesium alloys in individual branches of industries. With their usage for particular parts, a comparison with other construction materials, including the evaluation of using magnesium alloys and their advantages and disadvantages, is conducted.
|
|
|
Properties and in vitro Degradation of Metalic Biodegradable Materials
Ročňáková, Ivana ; Trojanová, Zuzanka (referee) ; Vojtěch,, Dalibor (referee) ; Podrábský, Tomáš (advisor)
Biodegradable metallic materials for medical applications have received considerable attention in recent years. The main reason is that they provide high potential for fabrication of temporal orthopedic implants such as bone fixation devices. Magnesium is an excellent candidate for fabrication of biodegradable implants due to its biocompatibility, mechanical properties similar to human bone and relevance for biological body functions. The fast degradation rate of magnesium and its biodegradable alloys in physiological environment limits its clinical application. Another attractive material in the field of biodegradable materials is zinc, which is among the essential elements in human body. Zinc exhibits an excellent corrosion resistance, and inferior biocompatibility compared to with magnesium. Hence, surface modification to form a hard, dense/porous, biocompatible and corrosion resistant modified layer has become an interesting topic in magnesium base biomaterials. Since hydroxyapatite is well tolerated by living organisms and in addition, improves the bone growth, it appears to be excellent candidate for such coatings on surface of biodegradable materials (e.g. Mg, Zn). This thesis is focused on comparison of corrosion behavior of pure non ferrous metals (Mg, Zn) and metals coated with hydroxyapatite, in simulated body fluids. The present approach is the use of modified atmospheric plasma spray technology to produce the hydroxyapatite coatings – suspension spraying. Composition and structure of the coatings and corrosion products were studied by light microscopy, scanning electron microscopy equipped with energy dispersive microanalyzer and X-ray diffraction. Corrosion of Mg and Zn samples was monitored by weight loss and determined by X ray and micro-tomography. The application of the HA coating resulted in decrease of corrosion rate of pure Mg. The corrosion rate of coated Mg samples was lower by 27,3 % in comparison with the corrosion rate of pure non coated Mg. Corrosion degradation of uncoated and coated Zn samples was minimal. The aplication of HA on the non ferrous surface appears to be a very promising method to improve corrosion and biological properties of these biodegradable materials.
|
|
| |
|
|
Microstructure and mechanical properties of biodegradable magnesium alloys
Faltejsek, Petr ; Ročňáková, Ivana (referee) ; Horynová, Miroslava (advisor)
The objective of this bachelor thesis is to create a summary of materials for biomedical applications, comparison of biodegradable and biocompatible materials and also summarization of biodegradable magnesium based alloys. The thesis has four parts. The first contains a description of each group of biomaterials. The second part is focused on magnesium and its alloys, including the evaluation of individual alloys with regard to biomedical applications. The third part contains information about the types of corrosion of magnesium and its alloys and various influences on the corrosion. The last part is focused on the influence of alloying elements on the human body.
|
|
|
The environmnetal impact of burning products
Ročňáková, Ivana ; Vávrová, Milada (referee) ; Doležalová Weissmannová, Helena (advisor)
The submitted thesis deals with the study of combustion products and their impact on the environment and human organism. It explains the nature of combustion and conditions under which the fire originates. In this action is developed a large number of different substances. As concrete examples of inorganic substances were selected following compounds: carbon monoxide, carbon dioxide, sulfur dioxide, sulphates, hydrogen chloride, hydrogen cyanide, nitrous gases and ammonia. From the organic compounds were selected only a few examples, such as the burning of plastics or the subsequent fire extinguishing device is developed by a diverse range of organic compounds. The wide range of compounds was chosen phosgene, formaldehyde, acetaldehyde, PAHs and extremely toxic. When burning the noxious substances into the air first and then wet or dry slope to reach the other components of the environment. These combustion products have diverse adverse effects on both humans and the environment. In some cases, these substances have fatal consequences for all components of the environment.
|
|
|
Materials for the construction of frames of gravity bicycles
Hrubý, Erik ; Ročňáková, Ivana (referee) ; Juliš, Martin (advisor)
The presented bachelor thesis in it first part is focuses to the application of special racing bikes. The less known gravity disciplines with an explanation of their nature, the type of track and rules are presented. The second part of thesis deals with the structural design and fitting of mountain bikes used in each presented gravity disciplines. In the last part of thesis is a list of structural materials from which are manufactured special bike frames focusing on their mechanical properties, advantages and disadvantages and other usage.
|
|
|
Properties and in vitro Degradation of Metalic Biodegradable Materials
Ročňáková, Ivana ; Trojanová, Zuzanka (referee) ; Vojtěch,, Dalibor (referee) ; Podrábský, Tomáš (advisor)
Biodegradable metallic materials for medical applications have received considerable attention in recent years. The main reason is that they provide high potential for fabrication of temporal orthopedic implants such as bone fixation devices. Magnesium is an excellent candidate for fabrication of biodegradable implants due to its biocompatibility, mechanical properties similar to human bone and relevance for biological body functions. The fast degradation rate of magnesium and its biodegradable alloys in physiological environment limits its clinical application. Another attractive material in the field of biodegradable materials is zinc, which is among the essential elements in human body. Zinc exhibits an excellent corrosion resistance, and inferior biocompatibility compared to with magnesium. Hence, surface modification to form a hard, dense/porous, biocompatible and corrosion resistant modified layer has become an interesting topic in magnesium base biomaterials. Since hydroxyapatite is well tolerated by living organisms and in addition, improves the bone growth, it appears to be excellent candidate for such coatings on surface of biodegradable materials (e.g. Mg, Zn). This thesis is focused on comparison of corrosion behavior of pure non ferrous metals (Mg, Zn) and metals coated with hydroxyapatite, in simulated body fluids. The present approach is the use of modified atmospheric plasma spray technology to produce the hydroxyapatite coatings – suspension spraying. Composition and structure of the coatings and corrosion products were studied by light microscopy, scanning electron microscopy equipped with energy dispersive microanalyzer and X-ray diffraction. Corrosion of Mg and Zn samples was monitored by weight loss and determined by X ray and micro-tomography. The application of the HA coating resulted in decrease of corrosion rate of pure Mg. The corrosion rate of coated Mg samples was lower by 27,3 % in comparison with the corrosion rate of pure non coated Mg. Corrosion degradation of uncoated and coated Zn samples was minimal. The aplication of HA on the non ferrous surface appears to be a very promising method to improve corrosion and biological properties of these biodegradable materials.
|
guest ::
