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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Povrchová úprava dřevěných fasád

Slováčková, Hana January 2015 (has links)
This thesis deals with monitoring changes in surface finishing of spruce and larch wood in outdoors. Using outdoor weathering tests the properties of two kinds of paints were tested by - a thin glaze and oil paint, two shades from each. In this work, the influence of the composition of the paint on its durability and light fastness was examined. This issue is closely related to the resistance of coatings to weathering, including solar radiation (UVA and UVB), atmospheric oxygen, relative humidity, temperature, precipitation, biological attack, chemical impacts (air pollution, acid rain, etc.).
12

Vliv aktivity ?-amylásy na kvalitu běžného pečiva

Olšová, Renata January 2015 (has links)
The main aim of the diploma thesis was to explore the effect of alpha-amylase addition on the quality of rolls. These enzymes were isolated from Trichoderma viride and Aspergillus oryzae. Both enzymes are aimed at using in bakery industry. First of all, the activity of both enzymes was measured and found out, that the used methodology was suitable. Afterwards, both enzymes were added to the recipe - always the lowest and the highest recommended amount. In total ten samples were baked using rapid mix test, where number 1 and 6 were control samples without alpha-amylase addition in order to evaluate the effectiveness of added enzymes. Two types of flour were used - wheat flour T 530 (samples number 1 - 5) and spelt flour (samples number 6 - 10). In the end, sensory analysis was conducted, the volume of rolls subtracted and the hardness of rolls measured 2, 24 and 48 hours after baking using TIRAtest method.
13

Studium faktorů ovlivňujících odolnost proti opotřebení kovových materiálů / Assessment of Factors Influencing Wear Resistance of Metallic Materials

Cieslar, Jiří January 2016 (has links)
This thesis investigates the suitable chemical composition of a iron alloy with improved wear resistance. A unique set of alloys with a specifically designated chemical composition was manufactured for experiments. Their properties in defined abrasive conditions was studied in laboratory conditions. Wear resistance was determined on an experimental bench with bound particles. Material properties description was always complemented with information gained during material metallographic structure investigations. All the results were compared with results achieved for commercially available weld deposition materials (specifically designated for abrasion conditions). These (weld deposition) materials were subjected to an identical set of laboratory experiments and additionally to a set of experiments under inservice conditions. This thesis offers new knowledge about the relationship between material hardness, material structure and wear resistance. The outlined results also give evidence about the correlation between results gained under laboratory conditions and those gained under in-service conditions (in relation to material structure and hardness). At the end of the thesis the knowledge gained from these experiments is applied to a specific application the service life extension of plough blade segments. On this basis a new material is designed which will extend service life without additional demands on the costs, and the approach to the renovation of worn plough blade segments is justified.
14

Návary proti opotřebení / Wear resistence of cladding

Pagáč, Aleš January 2014 (has links)
The subject of this Diploma thesis was study of wear resistant deposits, including appropriate basic and filler materials and welding technologies suitable for a particular application of hard carbide overlays of blade mixer for foundry sand. Analysis of suitable filler materials focused on extreme abrasion and select tungsten carbide hardfacing, together with a selection of appropriate overlays welding methods for welding tungsten carbide, including the conditions and parameters surfacing. The practical part deals with the design and evaluation of the experiment, three samples welding of non-alloy structural steel, tungsten-carbide hardfacing, technology MCAW - WC flux cored electrode in protective active gas.
15

Možnosti regulace vneseného tepla - experimentální ověření / Possibilities of regulation of stored heat - experimental verification

Mášová, Pavla January 2011 (has links)
This diploma thesis elaborated within the Manufacturing Technology Master´s study program considers various possibilities of welding which can regulate the amount of inputted heat into the welded joint. For experimental testing, material X2CrTi12 (ferritic stainless steel) was chosen, welded by means of methods suitable for the material. Welding methods included TIG, plasma, and laser. Further possibilities of heat input are suggested, such as pulse welding, Rapid, Fast Root, Surface Tension Transfer, Cold Metal Transfer, ColdArc, and Wise. The aim of the experiment is to compare the amount of heat input and its effect on particle growth and hardness.
16

Studium vlivu velikosti svazku na hloubku prokalení materiálu 42CrMo4 při laserovém kalení / The study of the spot size influence on the depth of hardening of the material 42CrMo4 during laser hardening

Kříž, Daniel January 2015 (has links)
This master thesis is focused on surface hardening by using disk laser. Ten samples made of 42CrMo4 steel were hardened at varying speeds of quenching and diameter of the laser beam. The theoretical part initially describes the types of lasers. Further it describes methods of surface hardness processing such as kinds of hardening and chemical-thermal treatment, followed by description of the used material. Images of macrostructure, microstructure and compared values of hardness of single samples are evaluated in the experimental part. The thesis subsequently contains a technical-economic evaluation. Appropriate parameters for surface laser hardening are evaluated in the conclusion.
17

Povrchové kalení ocelí výkonovým polovodičovým laserem / Surface hardening of steels by high power diode laser

Bazalová, Lucie January 2014 (has links)
The master thesis deals with the technology of surface hardening of steels by high power diode laser. The thesis is an experiment of surface hardening of steel 12 050 on various parameters of speed movement of the laser head and used power. At first, the work deals with the possible technology of surface hardening, industrial lasers and possible methods for measuring hardness. It describes the material used and the evaluation of the macrostructure and microstructure of the samples and evaluates the achievement of hardness, depending on the distance from the surface. The results are used to assess the suitability of the parameters during quenching.
18

Navařování Stellitem na ocel 1.4122 / Stellite cladding on steel 1.4122

Daumer, Tomáš January 2016 (has links)
Master‘s thesis describes issues of stainless steel welding. The analysis carries out the stainless steel‘s state of art in term of welding, chemical composition, physical and mechanical properties. Experimet is based on cladding of Stellite alloys to martensitic stainless steel X39CrMo17-1. The practical part describes the used devices and carries out evaluation of specifically designed heat input, macrostructure and hardness.
19

Vliv okolní krajiny, rybářského hospodaření, vnějších a vnitřních činitelů na jakost vody v rybnících / The influence of the surrounding landscape , fishery management , external and internal factors on water quality in ponds

Janáček, Štěpán January 2016 (has links)
The thesis deals with the influences that affect water quality in the ponds . It focuses on selected factors which define water quality . These include e.g. the amount of dissolved oxygen in the water , ammonia, etc. To determine the change in water quality in a fish breeding tank, measured quality of water at the inlet of the tank and at its drain. I enter into the analysis and facts about the amount of fish stocking in ponds , basin shape , location of the pond in the countryside , farming in the watershed .
20

Vliv trajektorie elektronového svazku na vlastnosti povrchu oceli 42CrMo4 / Influence of the electron beam trajectory on the surface properties of steel 42CrMo4

Mikuš, Tomáš January 2018 (has links)
The thesis deals with surface quenching of steel 42CrMo4 by electron beam. Influence of technologic parameters and beam deflection on properties and structure of prepared layers is studied. Electron beam surface quenching was applicated with and without melting of the surface. Structures of layers made by electron beam quenching were compared with structures made by laser and electromagnetic induction. Structures and phases were analysed by optical microscopy, SEM and roentgen diffraction. Hardness was measured on hardened layers.

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