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Model of the metropolitan optical network
Prudík, Jiří ; Hudcová, Lucie (referee) ; Křivák, Petr (advisor)
The purpose of this master’s thesis is foremost to provide a simple guide how to build elements of optical metropolitan area network. The basic model consists to sequence of construction, network topology, passive and active parts. The collection contains examples of alternative technology such as Wireless LAN with different frequency. The optical network construction based on optical cable, fibres, splices, trays, adapters, connectors and active parts for example a lot of media convertor models. After that there are demonstrating type of wavelength division multiplexer used in metropolitan area network – passive planar PCL splitter. One of the passive planar splitter are used to increase optical fibre channel. At the end of the collection a simplified examples of used measurements – optical time domain reflectometry and optical fibre transmission. Contains standard protocols or reflectogram. The conclusion of this thesis summarizes costs of FTTb (Fibre To The Building) model of optical metropolitan area network in Czech republic and future contribution for society.
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The influence of conditioning on the mechanical properties of polymers produced by injection molding technology
Neužil, Tomáš ; Řehořek, Lukáš (referee) ; Válka, Libor (advisor)
The aim of the thesis is to determine change of mechanical properties of three types of damp polymeric materials (polyamides) depending on the water content inside material. Before testing, specimens of all three types of materials were placed inside the air conditioning chambers until equilibrium (conditioned) state was reached when the specimens received the maximum possible amount of water from the environment. A total of three conditioning levels were set, representing besides the standard level of conditioning both extreme states like state when the material was fully dried and the state where the material content the largest possible amount of water. With the increasing content of water bound in material, there is a characteristic change in the mechanical properties of the material, such as a decrease in strength and modulus of elasticity and an increase in toughness and ductility. To examine material properties change, tensile and Charpy impact tests were performed, Charpy impact tests were performed for both specimens with and without a notch. Besides changes in mechanical properties, the rate of water absorption was also observed depending on the materials and its filling.
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Corrosion resistance of PA and PC components
Mikel, David ; Pospíšil, Ladislav (referee) ; Jančář, Josef (advisor)
The influence of two lubricating and cleaning agents and diesel fuel on environmental stress cracking of polyamide reinforced by glass fibers and polycarbonate was studied in this master thesis. Testing of environmental stress cracking was performed by the method of critical bending deformation. Bergen elliptical strain jig was used for testing. The test liquids caused varying levels of environmental stress cracking of amorphous polycarbonate, but they did not cause environmental stress cracking of glass fiber reinforced polyamide. The test method used allows testing the resistance of both materials against environmental stress cracking of any liquid. The results can be used to design products that are expected to be exposed to corrosive liquids. Quantification of the influence of stress free corrosion on the static and impact properties of polycarbonate and glass fiber reinforced polyamide was performed by accelerated test. Specimens were exposed to test liquid and an elevated temperature of 70 °C. The mechanical properties of the tested materials were significantly affected by elevated temperature exposure. The yield strength of the polycarbonate has increased and the toughness has decreased due to physical aging. The tensile strength of glass fiber reinforced polyamide has increased due to a decrease of the moisture content of the material.
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The impact of selected nodes on strength of flat slings under static load
Komorous, Miroslav ; Vomáčko, Ladislav (advisor) ; Bedaň, Jindřich (referee)
Název práce Vliv vybraných uzlů na pevnost ploché šité smyčky při statickém zatížení. Cíle práce Cílem práce je posoudit pevnost plochých šitých smyček při statickém zatížení a vliv uzlů na snížení jejich pevnosti. Metody Zpracovávaná studie je designována jako dvoufaktorový experiment, při kterém zkoumáme vliv použitých uzlů na pokles nominální pevnosti u dvou typů smyček. Měření bylo prováděno na horizontálním trhacím stroji. Byly vybrány smyčky materiálu dyneema, polyamid a nejčastěji používané uzly (vůdcovský, osmičkový a devítkový). Výsledky Větší pevnosti dosáhly smyčky materiálu Polyamid 26,0 ± 1,1 kN a pevnosti v průřezu 1,3 kN na 1 mm2 . Smyčky materiálu dyneema dosáhli pevnosti 25,1 ± 0,9 kN a pevnosti v průřezu 1,3 kN na 1 mm2 . Na smyčce materiálu polyamid nejméně snižoval pevnost vůdcovský uzel. Smyčka praskla při tažné síle 17,4 ± 0,7 kN. U dyneemy to byl uzel osmičkový s hodnotami 12,2 ± 0,8 kN. Závěr Pro použití smyček v kombinaci s uzly bychom mohli doporučit materiál polyamid, kde uzel snižuje méně nominální pevnost než u dyneemy. Klíčová slova Horolezectví, sportovní lezení, dyneema, polyamid, trhová zkouška
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Morphology of Polyamide 12 and Polyamide 11 formed at overpressure and underpressure
Bělašková, Marie ; Tocháček, Jiří (referee) ; Bálková, Radka (advisor)
In this master thesis it was studied morphology of polyamide 12 (PA12), polyamide 11 (PA11) and their blends in the percent ratios 95/5, 75/25, 50/50, 25/75 and 5/95 formed at pressure 7 MPa in a calorimeter both after continual heating and cooling and after annealing and isothermal crystallization. Neat polyamides and blends were further characterized by thermogravimetric analysis, differential scanning calorimetry at atmospheric pressure, Fourier-transform infrared spectroscopy in attenuated total refection, and X-ray diffraction analysis. The increased pressure improved level of polyamide chains ordering in crystal lamellae. Thermal annealing improved especially ordering of PA12, isothermal crystallization led to considerable increase of crystallinity, whereas PA11-rich blends supported perfection of PA12 crystals. Partial transformation of - to -structure occurred in case of neat PA12 at high pressure, the change of the chain conformation into the closer one occurred in neat PA11 without transformation of the type of crystal structure.
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Design of manufacturing technology for door elastomer grommet
Kavan, David ; Stehlík, Ing. Jaroslav (referee) ; Kandus, Bohumil (advisor)
The goal of this project is design of manufacturing technology for door elastomer grommet in a series of 400 000 units per year. As a proposed solution of manufacturing technology has been chosen multicomponent injection moulding. Appropriate thermoplastic elastomer and polyamide was chosen based on the knowledge gained in theoretical study of materials and technologies elaborated in the second part of the project. Moreover, the shape of the door grommnet was redesigned in accordance with the chosen technology. Working machine was chosen from manufacturer Arburg, model Allrounder 630S in a two-shot design, complemented by the index unit. A cost of production of one piece of the door grommet was determined in an economic evaluation. This cost was compared with current cost of production and new technology reducing manufacturing costs of one series by 25%.
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Production technology of the connector body from recykled material
Brhel, Michal ; Sedlařík, Vladimír (referee) ; Kandus, Bohumil (advisor)
Study developed during the Master's degree studies of Mechanical Engineering deals with the use of recycled plastic in the injection molding and its influence on the mechanical properties of the mold. Examined product is used in the automotive industry as a connector body. The housing is manufactured from a plastic material, polyamide. The annual production volume of 3 000 000 pieces. According to tests specified in standard USCAR2 regrind influence on mechanical properties and dimensions was evaluated. After the technical evaluation of the project, research was also judged from economic point of view. In this task, savings with the different content of the recycled material during production was calculated. The final chapters justify change of properties and they are proposing the use of recycled materials in practice.
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Effect of radiation cross-linking of PA on its thermomechanical properties
Mikel, David ; Tocháček, Jiří (referee) ; Jančář, Josef (advisor)
The influence of ionizing radiation on thermomechanical properties of polyamide reinforced by glass fibers was studied in this bachelor thesis. Ionizing radiation caused reduction of crystallinity, melting and crystallization temperature of polyamide. Tensile strength and tensile modulus increased due to irradiation, meanwhile elongation at break decreased. Notched and unnotched impact strength at laboratory and lower temperature increased with dose of radiation and after reaching the maximum it decreased for higher doses of radiation. Heat deflection temperature increased significantly with dose of radiation and after reaching the maximum it decreased for higher doses of radiation, too. Based on measured properties of investigated material was chosen optimal dose of radiation. Radiation rosslinking is an appropriate technology for increasing dimensional stability at elevated temperatures of polyamide reinforced by glass fibers.
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Study of electric properties of composite
Bariš, Marián ; Havlíček, Svatopluk (referee) ; Polsterová, Helena (advisor)
The theme of this Bachelor's thesis is a problematics of composite materials. On a given samples of polyamide with a various weight filling of a milled mica were measured resistivity, permittivity and loss factor on a consequence of a temperature and filling. The chosen type was a filling with a milled mica in range from 0 to 40 of a weight percentage, temperatures were in range from 20 °C to 90 °C.
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Design of manufacturing technology for plastic cover electrical device
Kočárek, Karel ; Kebrle, Ondřej (referee) ; Kandus, Bohumil (advisor)
This thesis contains of theoretical part which deals with injection molding, properties of some polymer materials are included also. Design of plastic injection mold for cover of electronic device is presented in practical part. Manufacturing parameters and injection machine selection are specified with mold structure consideration. Production costs and the final price of the plastic part are calculated in economical evaluation.
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