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Mechanical properties of polymers produced by 3D printing technology
Král, Filip ; Moravčík, Igor (referee) ; Válka, Libor (advisor)
The thesis deals with the dependence of mechanical characteristics on the anisotropy of polymers Nylon 12 and Ultem 9085 made by a 3D printing technology Fused Deposition Modeling (FDM). The evaluation of the material characteristics was performed on the basis of tensile and non-instrumental impact tests. It was proven that the material characteristics are strongly dependent on anisotropy, i.e. on layer thickness and raster angle for both types of polymers.
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Usage of fast-reacting SBS polymer in the production of asphalt mixtures
Dohnálek, Jakub ; Dašek, Ondřej (referee) ; Hýzl, Petr (advisor)
The subject of this diploma thesis is a research of bituminous binder modification by fast react-ing polymer SBS. The theoretical part covers an introduction to bituminous binders, their pro-duction, chemical and physical-mechanical properties. The identification of bituminous binders and their use in bituminous mixtures is briefly described. To conclude, current modification methods are described in detail and important modifiers are introduced. In the practical part, three applied tests (softening point, elastic recovery and penetration) are described in detail. The bituminous binders tested (20/30, 30/45, 70/100, PMB 25/55-55 and PMB 45/80-50) and the fast-reacting polymer SBS are introduced. Samples with two weight percentages of SBS, 7,5% and 10%, are produced. Two mixing times, 60 seconds and 600 seconds were used to mix the bituminous binder and SBS. In conclusion, the results are evaluated and commented. Further research suggestions regarding this field are recommended.
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Ecotoxicological evaulation of polymeric substances
Milatová, Martina ; Vávrová, Milada (referee) ; Zlámalová Gargošová, Helena (advisor)
Polymers or their modifiers may become parts of a wide range of products. After the end of life cycle useful parts of the products are recycled but significant parts still become household waste. It´s therefore desirable not only by law on chemicals and chemical products, but also according to the requirements of European directive REACH, to assess the impact not only chemical but also the additives of all products or products themselves in terms of their impact on the environment. For these purposes it serves ecotoxicity tests, which allow prediction of the influence test compounds in the environment. In this diploma thesis were evaluated polypropylene modifiers, which are commercially produced. Use of ecotoxicity tests were evaluated maleic anhydride and itaconic anhydride effects on the environment. Alternative tests have been used for toxicity and namely Thamnotoxkit FTM the organism Thamnocephalus platyurus and Daphnotokit FTM the organism Daphnia magna. The phytotoxicity test groups were selected toxicity tests: Sinapis alba root growth inhibition toxicity test, Allium cepa L root growth inhibition toxicity test and Semi-chronic toxicity test on Lemna minor L. From marine toxicity tests was performed Acute inhibition test of brine shrimps Artemia salina.
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Technologies using organic materials
Galbička, Tomáš ; Chmela, Ondřej (referee) ; Hubálek, Jaromír (advisor)
There are sumarized some of the basic organic materials for produce of organic parts. Two types of theese materials are introduced PPV and PFV and their derivatives, which tuning their resulting properties in area of electrical, optical, chemical, and thermal parameters. There is designed and created system for mechanical bending of adhesive SMD devies on flexible printed circuit board and compared properties of some conducting adhesives.
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Peer-To-Peer Web File Sharing in a Group
Pokorný, Filip ; Španěl, Michal (referee) ; Herout, Adam (advisor)
The diploma thesis deals with file sharing among users through peer-to-peer transfer in a web environment. The aim was to create a simple application which would provide a group of users with an opportunity to share files among them without any presence of third party or limitation. I have met the target using modern web technologies, of which the most important was WebRTC library through which peer-to-peer transfer has been implemented. These technologies were supported by optimased algorithm and the most recent tools for processing and storage of shared files. The result is a real-time application enabling users to create rooms, in which they can share their files. This product was subjected to speed tests, thanks to which the application turned out to be the fastest in the tested environment contrary to solutions with similar nature or any other commonly used tools for file sharing.
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Studium a vývoj polymer-cementových kompozitů s důrazem na vysoký obsah druhotných surovin a kompenzaci objemových změn
Hermann, Radek ; Bydžovský, Jiří (referee) ; Reitermann, Pavel (referee) ; Kolísko, Jiří (referee) ; Drochytka, Rostislav (advisor)
Reducing of humanity's carbon footprint is currently one of the main directions of global research. Another significant problem is the disposal, recycling and secondary use of waste materials produced from a wide range of industries and municipal waste. This thesis deals with the problematics of polymer-cement composites, which are most often used for rehabilitation, reprofiling and structural repairs, especially of concrete structures. The thesis examines and verifies the possibilities of utilization of a large amount of secondary raw materials and waste as a substitute for cement as a primary binder. At the same time, the work deals with the full replacement of the primary filler with waste raw materials, for which there is currently no other use. The work also addresses and verifies the influence of several commonly available commercial polymer dispersions. The work deals with the use of liquid, but also powdered polymeric additives of various bases. The work also deals with the problematics of volume changes of the hydration process of polymer-cement composites and the effect of volume changes on the physical-mechanical properties of composites. The influence of volume changes that occur during the hydration of polymer-cement composites is a significant criterion in the selection and use of these composites. The volume changes of the material have a great influence especially on the maximum layer thickness and the maximum area that can be repaired with the material without the risk of cracks and the need to create a working joint. The results of this work are associated with a reduction in the economic and environmental impacts of production and use of polymer-cement building materials and increase the usability of these materials mainly due to the possibility of remediation of larger areas than previously possible.
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The Role of Charge Regulation in Weak Polyampholytes
Lunkad, Raju ; Košovan, Peter (advisor) ; de Sousa Dias, Rita (referee) ; Gonzalez, Jose Luis Garces (referee)
A weak polyampholyte is a polymer that consists of both acid and base groups along the chain. In aqueous solutions, these groups dissociate in a certain pH range, leading to a dramatic change in the overall charge of the polyampholyte from positive to negative as the pH increases. The ability of weak ampholytes to switch their charge in response to changes in pH makes them useful in various applications. Despite the considerable research on weak polyampholytes, the understanding of some aspects is still insufficient. To address this, I systematically investigated the charge regulation of weak polyam- pholytes, specifically peptides, both in solution and during their interaction with polyelectrolytes. Furthermore, I also looked at the charge regulation of polyzwitterions. All these studies were carried out using a simple coarse-grained bead-spring model in Langevin dynamics simulations. In addition, I used the constant-pH ensemble to account for the ionization reactions of acid and base groups in the implicit solvent. Through our simulations, we made significant advancements in understanding how charges and the ionization states of acid and base groups in various peptides and polyzwitterions respond to pH changes. By comparing simulation results with the ideal results predicted by the...
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Use of 3D printing technology in the automotive industry
Hyhlík, Pavel ; Šafl, Pavel (referee) ; Binar, Tomáš (advisor)
This thesis deals with 3D printing technology and its applicability to the automotive industry. It discusses the types of technology, the materials used for 3D printing, required software and the specific applications. One of the materials is selected and analyzed for its properties, after which spare parts are designed and manufactured from it. The thesis includes a case study looking at the economic viability of additive manufacturing for engineered parts.
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Možnosti využití mikroorganismů pro rozklad plastového odpadu
HEŘMANOVÁ, Pavlína
Heřmanová, P. Possibilities of using microorganisms for the decomposition of plastic waste.. České Budějovice, 2023. Bachelor Thesis at Faculty of Agriculture and Technology of University of South Bohemian. Thesis Supervisor Kristýna Perná Mgr.Ing. Ph.D. This work deals with possibilities of biodegradation of plastics using microorganisms. The production of the most used plastics and their use is described here, and I also deal with plastic waste and its leakage into the environment. Attention is paid to microorganisms and their enzymes, which are capable of biodegrading plastics, and the met hods used in evaluating the course of biodegradation are further evaluated
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