National Repository of Grey Literature 39 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Statistical analysis of production
Kovaříková, Ludmila ; Grepl, Mojmír (referee) ; Maroš, Bohumil (advisor)
The aim of Master's thesis is to apply statistical methods in production process. The assignment of the thesis is to describe and evaluate pressing process which is the part of posistor production. The first theoretical part contains introduction to the mathematical statistics, verifying assumptions about the data, describing the regression analysis, the analysis of variance and the part of the design of experiment. The second practical part is focused on design, performing and interpreting of experiments. The thesis is developed according to requirements of company EPCOS s.r.o. Šumperk. Statistical program MINITAB Rlease 14, which is supported by company, was used for all computations.
Design of Experiment
Lachnit, Zdeněk ; Bednář, Josef (referee) ; Kotek, Luboš (advisor)
The main subject of this master thesis is to evaluate using of Design of Experiment in industrial company in the development of LED modules for cars. In background study Design of Experiment methodology is described. Next part of background study describes the general principles of termography measurements, next chapter includes the information’s about LED technology and temperature degradation. At the beginning of the practical part is a description of the team analysis due to selection of factors, next chapter validates importance of vias. In next chapter methodology of print circuit board preparations and measuring are described. A next chapter describes the implementation of design of experiment at voltages 8 V, 13,5 V, 16,5 V. Designs of Experiments were made for four or five factors. The reason for this decision was the manual adjustment of printed circuit boards. At the end of each Design of Experiment is the recommendation of factors and interactions settings with regard on response, which is the minimal temperature. At the end of master’s thesis is the final evaluation.
Optimization of EDM process control parameters
Prokeš, Tomáš ; Beneš, Libor (referee) ; Bednář, Josef (referee) ; Matoušek, Radomil (advisor)
The dissertation thesis is focused on the optimization of control parameters of an EDM machine; the subject of optimization is cutting speed and surface topography. The first part of the thesis contains a research study on the technology of electrical discharge machining with the attention paid to the optimization methods use for control parameters of this process. The second part of the thesis is focused on real application of knowledge gained from studied sources. Here, a design of experiment aim at optimizing the parameters of the EDM machine is designed and carried on to maximize the cutting speed with the highest possible surface quallity. The result of the work is to build adequate regression models and find the optimal setting of machine control parameters.
Testing of Cutting Tools for Multi-Axis Machining at Machining Centres
Dvořáček, Jan ; Mrkvica, Ivan (referee) ; Janáč, Alexander (referee) ; Píška, Miroslav (advisor)
The thesis is focused on testing of the cutting tools for machining on five axis machine tools and possibility of implementation of designed experiments in this area. The theoretical section focuses attention on analysis of specific features during five axis machining, including chip cross section and particularity of tool testing under high speed cutting conditions with consideration of dynamic stability of cutting tools. In the thesis force loading of the tool is discussed as well as its measurement process, considering force development caused by tool wear and data analysis. Description of designed experiment and its application to the area of tool testing is included as well. All theoretical predictions are followed by experimental verifying by extensive number of experimental tests, including evaluation of cutting tool condition, influence of hard coatings on cutting power of the tools, etc. For each of testing conditions are designed specific methods of processing of gathered data as well as evaluation of power of the cutting tools. Gathered data were processed by means of statistical evaluation and by statistical methods of designed experiments. The thesis contains also the extensive number of records and analysis, documented by means of light microscopy as well as electron microscopy.
Solder Joint Reliability and Wetting Characteristics Influence
Labaj, Radek ; Stejskal, Petr (referee) ; Starý, Jiří (advisor)
This thesis deals with the methodology of testing the wetting characteristics for different material and process effects in the double-plated base material. Testing is performed by wetting balance method. There is designed procedure to calculate the angles on each side of the non-homogeneous material. The Design of Experiments method is used to interpret the results, by using this method are also interpreted electrical and mechanical properties of solder joints. The correlation with wetting characteristics is discussed.
Production process optimization
Drábková, Veronika ; Jankových, Róbert (referee) ; Fiala, Alois (advisor)
This master´s thesis is aimed at the strategy and implementation of DOE (planned experiment) and QFD (quality function deployment) in business. There are described about these methods. It deals with their use for a given problem. The last section provides a possible procedure in the enterprise.
Obtaining and complex charaterization of Aronia spp. extracts
Seidlová, Kateřina ; Zemanová, Jana (referee) ; Veselá, Mária (advisor)
Aronia (Aronia melanocarpa) is a berry fruit with distinctive sensory characteristics and health-promoting properties. Polyphenols are the main bioactive compounds found in aronia including natural pigments – anthocyanins. Bioactive compounds are usually obtained from natural materials by extraction, in this work, two methods of extraction were compared – maceration and PHWE. Based on the total phenolic content, maceration was chosen as a more suitable method and then was optimized with statistical model – Design of Experiment. Optimal conditions were set to temperature of 30 °C, extraction agent 50 % ethanol, solid-solvent ratio 10 g per 50 ml and time of extraction for 30 minutes. Extract obtained under these conditions was characterised by total phenolic content – 1441 ± 90 mg/100 g DW, total anthocyanin content 943 ± 8 mg/100 g DW and antioxidation activity by ABTS 24,78 ± 0,09 molTE/g. In total of 25 volatile compounds were indentified in the optimal extract with content > 0,5 %. Major part created aldehydes and esters, with the main compounds being benzaldehyde (32,25 %) and methyl hexanoate (21,37 %).
Influence of concentration of selected pearlitic elements on structure and properties of spheroidal graphite cast iron
Kazdera, Vojtěch ; Kaňa, Václav (referee) ; Záděra, Antonín (advisor)
This masters thesis deals with the influence of selected pearlitic elements on the mechanical properties and structure of spheroidal graphite cast iron. The theoretical part analyses the parameters that have a major impact on the mechanical properties and structure of cast irons. In the practical part, the influence of Cu, Mn and thickness on the mechanical properties and structure of spheroidal graphite cast iron is determined by means of a planned experiment. The measured values were then statistically processed and the result is equations for the theoretical calculation of mechanical properties.
Winery wastewater treatment
Horňák, David ; Procházková, Michaela (referee) ; Touš, Michal (advisor)
Wastewater management is a current topic for wineries, as wastewater treatment accounts for a large part of operating costs. Currently, technologies based on biological processes are mostly used to treat wastewater from wineries. However, these have a number of drawbacks, such as higher investment and operating costs, a large footprint or the requirement for the necessary technical knowledge of the operators. This paper deals with the selection of an economically less demanding technology for the treatment of winery wastewater and the experimental assessment of its efficiency with respect to the removal of chemical oxygen demand (COD). Photo-Fenton oxidation was selected based on a thorough literature search. The Box-Behnken design was used to design of the experiment. Based on the experiment, the optimum operating conditions were found to be temperature 25 °C, pH 3, Fe2+ ion amount 20,2 mg/l, H2O2/Fe2+ ratio 64 and reaction time 3 h. The achievable COD removal efficiency is 11,8 %, which is not consistent with the values reported in the literature. The main reason for the low efficiency could be the insufficient intensity of the UV radiation used. Further research could build on the optimal conditions found and address the shortcomings of this experiment.
Foaming of fermentation residues during a vacuum evaporation
Knob, Jan ; Brummer, Vladimír (referee) ; Vondra, Marek (advisor)
The diploma thesis deals with the processing of digestate, which is the remaining material after biogas production. It aims to experimentally prove how chosen operational parameters of antifoaming agents influence digestate foaming associated with the vacuum evaporating technology. Based on the research of available antifoamers and the issue of digestate foaming itself, it was observed how three selected antifoamers (i.e. rapeseed oil, silicone antifoamer Erbslöh Schaum-ex and oleic acid), together with the decrease in the pH factor of the evaporating digestate, influence the final foam production. For the purposes of the research, an apparatus simulating the vacuum evaporating process was set up in which the heated sample was brought to boil by gradual pressure decrease. The process of foaming was observed in a transparent cylinder of a testing culumn. The essential part of the experimental activity is represented by a planned experiment which by means of a DoE (Design of experiments) method proved rapeseed oil to be very efficient. In contrast, other antifoamers, as well as the influence of the pH factor decrease, manifested themselves as insignificant factors, while the oleic acid even supported the foaming. The supplementary measurements led to a more detailed research of the effects of rapeseed oil and to the construction of a mathematical model describing how the concentration of rapeseed oil undermines the amount of generated foam. The main contribution of the thesis is firstly the evidence that rapeseed oil plays an important part in the reduction process of digestate foaming and secondly the determination of minimum substance concentration leading to the foaming reduction of a particular sample which is considered efficient enough to enable functioning of a vacuum evaporator. The thesis has also experimentally demonstrated the influence of some polymer organic flocculants which have been proved to support the foaming.

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