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Statistical Analysis of Real Process Scrap
Širjovová, Zuzana ; Karpíšek, Zdeněk (referee) ; Bednář, Josef (advisor)
Quality, as well as stability of processes check is nowadays gaining on its significance. The main driving force of its increasing importance is the rapid expansion of series production. Large-scale manufacturing processes are concerned, in terms of the number of operators, direct and indirect influence on rejects, but also on process stability. There are several quality characteristics, defined by utility properties, that can be easily measurable (linear dimensions, solidity, elongation, humidity, concentration) or directly immeasurable, mostly subjective (fragrance, taste, color, comfort while using, appearance). Statistical Process Control-SPC features the preventive tool of quality control, because based on the early detection of significant divergences of the process from the predetermined level, it is possible to execute interventions in the process with the aim of maintaining the acceptable and stable level and improving the process. This manufacturing process check will be the topic of my thesis. At first, Shewhart's control charts analysis will be done to determine strong process instability. Consequently, analysis will be carried out in test chi-square, used to determine the influence of each factor on the process of stability (operators, type of shift, type of product, type of defect on the product). All the practical part will be processed in statistical software MINITAB15. The thesis will be complemented by the findings from the examination of the features of interval estimates of parameter p for binomial distribution - numeric stability in the various statistical software (specifically Minitab 15, Statistica, Matlab 7.8.0). Master's thesis was supported by project from MSMT of the Czech Republic no. 1M06047 Center for Quality and Reliability of Production.
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Use of Contol Charts in Quality Control
Ječmínková, Michaela ; Klimčík, Pavel (referee) ; Kropáč, Jiří (advisor)
This diploma thesis deals with use of Shewhart Control Charts in quality control. The thesis describes the currently used process of quality control in the enterprise. Afterwards practical guidance for implementation of the statistical process control of the selected component and evaluation of capability is provided. An application for creating control charts and monitoring the quality of the product is included.
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Non-destructive testing of gear-wheels
Krejčí, Martin ; Juliš, Martin (referee) ; Čech, Jaroslav (advisor)
This diploma thesis resolves aplication of particular non-destructive testing methods while producing castings of steel wheels and quality control of this process. There are described fundamentals of flaw detection, determination of flaw-generation cause and suggestions for optimalization of casting process and increasing of its quality.
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Possibilities of use spelt spikelets for baking products preparation
VOPÁTKOVÁ, Linda
Spelt (Triticum spelt L.) is commonly processed to wholegrain flour, especially in organic quality. Even this type of flour does not usually contain husks which are removed before milling. This thesis aims to evaluate a possibility of utilizing whole grains including husks in the bakery industry and its effect on the quality from the nutritional as well as technological point of view. Quality control analyses were conducted in 17 samples. These included whole meal flour of common wheat, whole meal flour of spelt without husks, white flour of spelt with husks, white flour of common wheat and white flour of spelt. Remaining samples were made of soft four and coarse meal mixed in various proportions. The alpha and omega for the quality of bread and other bakery products is the quality of ingredients, especially the flour. Therefore, it was necessary to determine quality values and conduct corresponding analyses (Zeleny sedimentation test, falling number, wet gluten content, protein content, etc.). All samples were also subject to measuring rheological characteristics of dough using Mixolab II. In whole grain meals, in which there is the highest risk of mycotoxin contamination, incidence of such contamination was surveyed using the ROSA Mycotoxin Strips method. In the end, the bakery test was conducted with selected 11 samples after which the volume of the baked products was evaluated. This was followed by sensory evaluation by respondents following a presented questionnaire. The bakery experiment showed that it is possible to use spelt grains with husks, but this was reflected in the sensory test by the respondents. They preferred products which are more common and they did not positively evaluate the new taste and texture.
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Quality control of blood products
NOVÁČKOVÁ, Barbora
The main theme of this bachelor thesis is a quality control of blood products which are prepared in the Transfusion Centre in the České Budějovice Hospital. In my thesis, I focus on the rudimentary blood products manufactured from whole blood. These include resuspended erythrocytes without a buffy coat (EBR), plasma (P), mixed thrombocytes without leukocytes from a buffy coat in a spare solution (TBSDR) and mixed thrombocytes without leukocytes (TBSD). The aim of this work is a statistical analysis of quality of the aforementioned blood products used in the past 5 years. Moreover, I have devised my own quality control of the newest blood products TBSDR. The theoretical part addresses blood donors´ control, methods of blood collection, blood processing and procedures which may significantly influence the quality of blood products. I also describe the examined blood products and the quality control process. In the practical part, I deal with the procedure of examining the particular parameters of blood products´ quality control and their assessment. After the preparation of blood products, sampling is done as well as the control of both efficient and undesirable components (erythrocytes, leukocytes, thrombocytes, hemoglobin, hematocrit). Assessment of stability and sterility of blood products (hemolysis, pH, coagulation factors) is done at the end of their expiration. I will focus more carefully on the TBSDR blood product quality control which starts one month after the blood product is implemented into a production process and which lasts six months. Statistical control of the process is applied during the quality control. In the past 5 years, the quality of blood products has been satisfactory. The newly implemented blood product TBSDR is more high-quality than the previous TBDS. TBSDR provides not only patients but also transfusion centers with many advantages.
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Statistical Analysis of Real Process Scrap
Širjovová, Zuzana ; Karpíšek, Zdeněk (referee) ; Bednář, Josef (advisor)
Quality, as well as stability of processes check is nowadays gaining on its significance. The main driving force of its increasing importance is the rapid expansion of series production. Large-scale manufacturing processes are concerned, in terms of the number of operators, direct and indirect influence on rejects, but also on process stability. There are several quality characteristics, defined by utility properties, that can be easily measurable (linear dimensions, solidity, elongation, humidity, concentration) or directly immeasurable, mostly subjective (fragrance, taste, color, comfort while using, appearance). Statistical Process Control-SPC features the preventive tool of quality control, because based on the early detection of significant divergences of the process from the predetermined level, it is possible to execute interventions in the process with the aim of maintaining the acceptable and stable level and improving the process. This manufacturing process check will be the topic of my thesis. At first, Shewhart's control charts analysis will be done to determine strong process instability. Consequently, analysis will be carried out in test chi-square, used to determine the influence of each factor on the process of stability (operators, type of shift, type of product, type of defect on the product). All the practical part will be processed in statistical software MINITAB15. The thesis will be complemented by the findings from the examination of the features of interval estimates of parameter p for binomial distribution - numeric stability in the various statistical software (specifically Minitab 15, Statistica, Matlab 7.8.0). Master's thesis was supported by project from MSMT of the Czech Republic no. 1M06047 Center for Quality and Reliability of Production.
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Non-destructive testing of gear-wheels
Krejčí, Martin ; Juliš, Martin (referee) ; Čech, Jaroslav (advisor)
This diploma thesis resolves aplication of particular non-destructive testing methods while producing castings of steel wheels and quality control of this process. There are described fundamentals of flaw detection, determination of flaw-generation cause and suggestions for optimalization of casting process and increasing of its quality.
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Use of Contol Charts in Quality Control
Ječmínková, Michaela ; Klimčík, Pavel (referee) ; Kropáč, Jiří (advisor)
This diploma thesis deals with use of Shewhart Control Charts in quality control. The thesis describes the currently used process of quality control in the enterprise. Afterwards practical guidance for implementation of the statistical process control of the selected component and evaluation of capability is provided. An application for creating control charts and monitoring the quality of the product is included.
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Calculation of Acceptance Sampling Plans for Inspection by Variables
Kaspříková, Nikola ; Klůfa, Jindřich (advisor) ; Dittrichová, Eva (referee) ; Slavík, Václav (referee)
Analysis of several acceptance sampling procedures is performed and improvement of the procedures is sug- gested in this thesis. The issue of an efficient calculation of exact (P1, P2) single sampling plans for sampling by variables and exact LTPD and AOQL single sampling plans for sampling by variables when the rejected lots are inspected is addressed. The calculation of the plans is done using exact formula for operating characteristic of acceptance sampling plan and the new plans have better characteristics compared to the plans computed in a usual way using just approximately valid formula for operating characteristic. The tables of plans calculated according to procedures suggested in this thesis are provided for a couple of input parameters combinations. Tools designed for working with acceptance sampling plans, tools for analysis and calculation of acceptance sampling plans is one of the outputs of this thesis. R language and environment for statistical computations was chosen for implementation. The tools are satisfactorily efficient and may be easily used even for acceptance sampling plans tables computation. Newly defined functions in R are supplied including their source code and basic documentation so that acceptance sampling plans can be computed as demanded in case that the particular input parameters set is out of the scope covered in the tables of plans provided here.
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