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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.
31

Vliv technologie výroby na vlastnosti forsteritu / The Effect of Production Technology on the Properties of Forsterite

Nguyen, Martin January 2018 (has links)
The main objective of this thesis is to evaluate the effect of production technology on the properties of forsterite. The theoretical part contains the fundamental parameters and the use of forsterite in the industry together with various possibilities of forsterite production. The main emphasis is placed on the characteristics of the raw materials for production as well as the raw materials possibilities of the Czech Republic. The end of the theoretical part contains a design for the production technology of forsterite, which will be verified in the practical part. The practical part verifies the use of various raw materials for the composition of the raw material mixture. The created test specimens were subjected to the X-ray diffraction analysis, the determination of tensile bending strength, thermal conductivity coefficient, apparent porosity, bulk density, apparent density, water absorption, permanent change in dimension on heating, refractoriness, thermal expansion coefficient, refractoriness under load and the thermal shock resistance. At the end of the practical part is the verification of the design of the production technology of forsterite.
32

Marketingový mix společnosti / Marketing Mix of a Company

Hudec, Martin January 2020 (has links)
The diploma thesis is focused on marketing mix of family viniculture. The theoretical part defined basic marketing concepts and variables of marketing mix. The analytical part contained detailed analysis, which are source for proposed part like a ways for improving of the marketing mix of the viniculture.
33

Návrh repliky letounu L-40 "Meta Sokol" - trup / Replica Design of L-40 "Meta Sokol " Airctaft - fuselage

Růžička, Miroslav January 2008 (has links)
This diploma thesis deals with the design of all-metal construction of fuselage of the replica L-40 Meta Sokol aircraft on the basis of CS-VLA regulation. As far as the aircraft is concerned, the thesis establishes the load of tail surfaces, landing gear and engine bed. Futhermore, it designs the construction of fuselage, tail landing gear, including the system of its retraction, wing-fuselage connection, engine bed and the primary design of cockpit. In the end, the thesis focuses on the fuselage production technology.
34

Návrh progresivní technologie výroby tělesa šoupátka / Advanced technology project of valve body

Štábl, Martin January 2011 (has links)
This diploma work is dealing with the progressive production technology proposal of the valve body type S43 components. This is the high-pressure valve for the classical power supply. Here in the work is described the structural design of the valves, the material of the valve body and its machinability. Following an analysis of the existing production technology is the new production technology proposal for this part. All is designed with regards to the business possibilities of the Armaturka Vranová Lhota company. In conclusion of the work is presented the technical economic evaluation of both the existing and the proposed manufacturing technology.
35

Úpravy střižných postupových nástrojů / Adjustments Shearing Procedure Tools

Dziuban, Jiří January 2016 (has links)
This thesis explains how to determine and eliminate the causes of quality problems in the production of connectors and small electronic components for the automotive industry. The process of making these components is carried out by use of both high speed and low speed metal stamping presses. There are descriptions of the different designs of editing punches, stamping dies, trimming and molding tools and how unplanned issues can occur during the production process. It addresses all the customer requirements for quality end products, listing the type of material, finishes and technology used for the production of individual components as well as their functionality, durability, and economic impacts. All examples of changes in the design or technology of metal stamping presses are based on many years of practical experience and most of them can be successfully applied in other similar type of instrument production.
36

Integrierter Umweltschutz bei der Produktionsstättenplanung : Methode eines planungsintegrierten Umweltschutzes (PLIUS) und Branchenstudie zur spanenden Metallbearbeitung

Löffler, Thomas 28 November 2003 (has links)
Aufbauend auf einer Analyse ausgewählter methodentheoretischer Ansätze der Produktionsstättenplanung und des Umweltmanagements wird eine Methode des planungsintegrierten Umweltschutzes bei der Produktionsstättenplanung entwickelt. Sie besteht zum Einen aus einer umweltbezogenen Analyse und Bewertung, basierend auf der Ökobilanzierung, die an die Belange der Produktionsstättenplanung angepasst und integriert wird. Zum Anderen erfolgt das Entwerfen umweltverträglicher Lösungen. Hierzu wird das Konzept des planungsintegrierten Umwelschutzes zu heuristischen Regeln operationalisiert und den Planungsaktivitäten Funktionsbestimmung/Dimensionierung/Strukturierung/Gestaltung zugeordnet. Es erfolgt abschließend der beispielhafte Einsatz der Methode in einer Branchenstudie zur spanenden Metallbearbeitung.
37

Influence of multiple welding cycles on microstructure and corrosion resistance of a super duplex stainless steel

Hosseini, Vahid January 2016 (has links)
Super duplex stainless steel (SDSS) has found a wide use in demanding applications such as offshore, chemical and petrochemical industries thanks to its excellent combination of mechanical properties and corrosion resistance. Welding of SDSS, however, is associated with the risk of precipitation of secondary phases and formation of excessive amounts of ferrite in the weld metal and heat affected zone. The present study was therefore aimed at gaining knowledge about the effect of multiple welding thermal cycles on the microstructure and possible sensitization to corrosion of welds in SDSS.Controlled and repeatable thermal cycles were produced by robotic welding. Oneto four autogenous TIG-remelting passes were applied on 2507 type SDSS plates using low or high heat inputs with pure argon as shielding gas. Thermal cycles were recorded using several thermocouples attached to the plates. Thermodynamic calculations and temperature field modelling were performed in order to understand the microstructural development and to predict the pitting corrosion resistance. Etching revealed the formation of different zones with characteristic microstructures: the fused weld zone (WZ) and the heat affected zone composed of the fusion boundary zone (FBZ), next to the fusion boundary, and further out Zone 1 (Z1) and Zone 2 (Z2). The WZ had a high content of ferrite and often nitrides which increased with increasing number of passes and decreasing heati nput. Nitrogen content of the WZ decreased from 0.28 wt.% to 0.17 wt.% after four passes of low heat input and to 0.10 wt.% after four passes of high heatinput. The FBZ was reheated to high peak temperatures (near melting point) and contained equiaxed ferrite grains with austenite and nitrides. Zone 1 was free from precipitates and the ferrite content was similar to that of the unaffected base material. Sigma phase precipitated only in zone 2, which was heated to peak temperatures in the range of approximately 828°C to 1028°C. The content of sigma phase increased with the number of passes and increasing heat input.  All locations, except Z1, were susceptible to local corrosion after multiplere heating. Thermodynamic calculations predicted that a post weld heat treatment could restore the corrosion resistance of the FBZ and Z2. However, the pitting resistance of the WZ cannot be improved significantly due to the nitrogen loss. Steady state and linear fitting approaches were therefore employed to predict nitrogen loss in autogenous TIG welding with argon as shielding gas. Two practical formulas were derived giving nitrogen loss as functions of initial nitrogen content and arc energy both predicting a larger loss for higher heat input and higher base material nitrogen content. A practical recommendation based on the present study is that it is beneficial to perform welding with a minimum number of passes even if this results in a higherheat input as multiple reheating strongly promotes formation of deleterious phases.
38

Constructive cooperative coevolution for optimising interacting production stations

Glorieux, Emile January 2015 (has links)
Engineering problems have characteristics such as a large number of variables, non-linear, computationally expensive, complex and black-box (i.e. unknown internal structure). These characteristics prompt difficulties for existing optimisation techniques. A consequence of this is that the required optimisation time rapidly increases beyond what is practical. There is a needfor dedicated techniques to exploit the power of mathematical optimisation tosolve engineering problems. The objective of this thesis is to investigate thisneed within the field of automation, specifically for control optimisation ofautomated systems.The thesis proposes an optimisation algorithm for optimising the controlof automated interacting production stations (i.e. independent stations thatinteract by for example material handling robots). The objective of the optimisation is to increase the production rate of such systems. The non-separable nature of these problems due to the interactions, makes them hard to optimise.The proposed algorithm is called the Constructive Cooperative CoevolutionAlgorithm (C3). The thesis presents the experimental evaluation of C3, bothon theoretical and real-world problems. For the theoretical problems, C3 istested on a set of standard benchmark functions. The performance, robustness and convergence speed of C3 is compared with the algorithms. This shows that C3 is a competitive optimisation algorithm for large-scale non-separable problems.C3 is also evaluated on real-world industrial problems, concerning thecontrol of interacting production stations, and compared with other optimisation algorithms on these problems. This shows that C3 is very well-suited for these problems. The importance of considering the energy consumption and equipment wear, next to the production rate, in the objective function is also investigated. This shows that it is crucial that these are considered to optimise the overall performance of interacting production stations.
39

Non-parametric modelling of pollution-generating technologies : theoretical and methodological considerations, with an application to the case of greenhouse gas emissions in suckler breeding systems in French grassland areas / la modélisation non paramétrique des technologies génératrices de pollution : considérations théoriques et méthodologiques, avec une application au cas des émissions de gaz à effet de serre dans les systèmes d'élevage allaitant dans les zones de prairies françaises

Dakpo, K. Hervé 15 June 2015 (has links)
La prise en compte des problèmes environnementaux dans la responsabilité sociale des entreprises a généré en économie de nombreuses propositions. Parmi elles, le cadre d’analyse basé sur l’évaluation de la performance en utilisant notamment les techniques d’enveloppement des données (DEA) s’est très vite répandu dans la littérature théorique comme empirique. Ce travail de thèse s’inscrit dans cette logique en mettant l’accent sur la modélisation des technologies polluantes. Par ailleurs, la question des changements climatiques et de la forte contribution de l’agriculture et en particulier de l’élevage dans les émissions de gaz à effet de serre (GES) impose à ce secteur de relever aujourd’hui en plus du défi économique celui de l’amélioration de sa performance environnementale. L’objectif général de cette recherche doctorale est donc de fournir un nouveau cadre d’analyse théorique et empirique dans la modélisation des technologies polluantes afin d’évaluer l’éco-efficience des systèmes productifs, en particulier le cas des émissions de GES en élevage extensif de ruminants. Dans un premier temps, nous montrons les limites théoriques et méthodologiques des modèles existants. Néanmoins, nous insistons sur le fait que les approches basées sur l’estimation de plusieurs sous-technologies indépendantes pour prendre en compte les différents processus présents dans les systèmes productifs sont très prometteuses. Dès lors dans un deuxième temps, nous proposons une nouvelle extension de la méthode « by-production » qui repose sur l’introduction d’interconnections entre les différentes sous-technologies impliquées afin de construire un système plus unifié. Dans un troisième temps, une comparaison empirique utilisant des données d’exploitations de viande ovine de notre extension avec les approches existantes a révélé certaines incohérences de ces dernières. Enfin pour aller plus loin, nous élargissons dans un quatrième temps notre approche afin de prendre en compte les aspects dynamiques et notamment la présence de coûts d’ajustement. Les résultats de l’analyse empirique entreprise avec des données d’exploitations bovines allaitantes (viande) ont révélé la nécessité de prendre en compte ces aspects, mais ont aussi révélé la forte hétérogénéité existante dans les stratégies d’investissements des éleveurs. / The growing importance of environmental matters in social responsibility of firms has generated many frameworks of analysis in the economic literature. Among those frameworks, performance evaluation and benchmarking using the non-parametric Data Envelopment Analysis (DEA) have increased at a very fast rate. This PhD research focuses on models that include undesirable outputs such as pollution in the overall production system, to appraise eco-efficiency of decision making units (DMUs). Besides, the recent awareness on the large contribution of agriculture and particularly livestock farming to global warming, has highlighted for this sector the challenge of reaching both economic and environmental performances. In this line, the overall objective of this dissertation is to provide a theoretical and empirical background in modelling pollution-generating technologies and to suggest theoretical improvements that are consistent with the particular case of greenhouse gas emissions in extensive livestock systems. Firstly, we showed that all existing approaches that deal with undesirable outputs in the non-parametric analysis (i.e. DEA) have some strong drawbacks. However, the models grounded on the estimation of multiple independent sub-technologies offer interesting opportunities. Secondly, I developed a new framework that extends the by-production approach through the introduction of some explicit dependence constraints that link the sub-technologies in order to build a unified system. Thirdly, an empirical comparison, using a sample of French sheep meat farms, of this by-production modelling extension with the existing approaches, revealed some inconsistencies of these latter. Finally, we expanded this new by-production formulation to account for dynamic aspects related to the presence of adjustment costs. The application to the case of French suckler cow farms underlined the necessity of accounting for dynamic aspects and also showed high heterogeneity in investment strategies of these farmers.
40

Návrh výrobní technologie součásti obráběcího stroje. / Production technology for part of metal cuting machine.

Kachyňa, Stanislav January 2010 (has links)
This thesis deals with design for manufacturing technology single part on machine FS, which is the connecting part. Work deals with the material of this component, therefore, cast iron with lamellar graphite, the properties of this material, primarily focusing on the machinability. Due to the shape and dimensions of the workpiece is also described problems cutting of box parts, the most common operations used in their manufacture, including cutting tools and materials. These findings are then applied in terms of the company TOS Kuřim - OS a.s. An analysis of current manufacturing technology and design is made for its amendment. In conclusion with the technical-economic evaluation.

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