• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 21
  • 8
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 41
  • 41
  • 14
  • 8
  • 8
  • 8
  • 7
  • 6
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 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

Gender a pracovní síla ve výrobních podnicích na Chomutovsku / Gender and manpower in production companies in the Chomutov region

Kroupová, Michaela January 2016 (has links)
Diploma thesis "Gender and manpower in production companies in the Chomutov region" is focused on historically and sociologically oriented research of employment of men and women in production companies in the Chomutov region over last 50 and 70 years respectively. The main aspects which are included in the theoretical part of this work are gender relations in the production companies, that is the history of the employment of women, horizontal and vertical gender segregation including wages and salaries and employee education. The analyzed data are from the period of mid 20th century and the beginning of the 21st century and focus primarily on the production companies of The Tube and Iron Rolling Mill and their current successor Sandvik. By means of data analysis, the methodical part of the thesis describes differences and changes which have ocurred in the horizon of last 50 and 70 years in the manpower employment in production companies with respect to gender. KEYWORDS Gender, Feminism, Manpower, Socialism, The Tube and Iron Rolling Mill, Production, Chomutov
32

Contribution à la compréhension du couplage thermomécanique en laminage à chaud sur l’évolution des défauts de coulée / Contribution at the comprehension of thermomechanical coupling on the evolution of the casting defect during rolling

Chevalier, Damien 21 December 2016 (has links)
Le laminage est un procédé de mise en forme à chaud permettant d’obtenir des barres de différents diamètres en partant de blooms issus de la coulée continue. Dans les bruts de coulée se répartissent des inclusions qui sont de natures, de formes et de tailles différentes. Le laminage va permettre de réduire le diamètre de la barre et d’agir sur la microstructure du matériau, notamment, en fragmentant et dispersant les inclusions. L’objectif des travaux de thèse est de contribuer à la compréhension des effets du chargement thermomécanique sur l’évolution des défauts de coulée en laminage. Vu la dimension des installations, les investigations expérimentales directes sur les moyens industriels ne sont pas envisageables. L’idée développée dans les travaux de thèse concerne la mise en place et la validation d’un essai de caractérisation à échelle réduite reproduisant le chemin thermomécanique subi par la matière au cours du laminage. Pour ce faire la ligne de laminage industrielle est modélisé afin d’obtenir le chargement thermomécanique de la barre au cours du laminage. Seules les sollicitations ayant un rôle majeur sur le comportement des défauts sont reproduites. Un essai dit de « forgeage libre » a ainsi été conçu, réalisé, mis en place sur les moyens de mise en forme de la plateforme VULCAIN de l’ENSAM. L’essai a été utilisé avec des défauts artificiels présentant des similarités comme la malléabilité avec les défauts réels. Une campagne expérimentale paramétrique a été menée sur les différents types de défauts. Les échantillons forgés ont été analysés par des méthodes non destructives comme les ultrasons, la radiographie et la tomographie X. Ces analyses ont permis de suivre le comportement du défaut et d’observer certains phénomènes mis en évidence dans la littérature comme l’apparition de cavité à l’interface défaut-matrice. / Rolling is a hot forming process dedicated to manufacture bars with different diameters. The initial product is a bloom from the continuous casting. The bloom contains inclusions which have different forms, sizes and distributions. The rolling reduces the diameter of the bar and acts on the material microstructure by fragmenting and dispersing the inclusions. The aim of the thesis work is to understand the behavior of the inclusions with the rolling thermo mechanical loading effects. The direct investigations on the rolling mill are not possible because of the size of the installations. To address this problem, the solution is to develop and validate a small scale characterization test reproducing the thermo mechanical loading of the rolled bar. To achieve this, the rolling mill is modeled. Only the solicitations which have a major role on the behavior of the defects are reproduced. An open-die forging test is designed, manufactured and implemented on the VULCAIN installation of the ENSAM. The artificial defects which have a similar malleability to the real defects are integrated into the sample. A parametric experimental campaign has been conducted on the different defects. The forged samples have been analyzed with non-destructive methods such as ultrasound, radiography and tomography. These analyses allowed to follow the behavior of the defects and to observe certain phenomena illustrated in the literature such as the emergence of a cavity on the defect-matrix interface.
33

[en] DEVELOPMENT OF MICROALLOYED STEEL FOR THE PRODUCTION OF REBAR / [pt] DESENVOLVIMENTO DE AÇO MICROLIGADO PARA A PRODUÇÃO DE VERGALHOES NERVURADOS

LEONARDO MIRANDA NUNES 18 January 2018 (has links)
[pt] O desenvolvimento de um aço microligado para a produção de vergalhões nervurados, busca atender a modernização das estruturas de concreto armado e a industrialização na construção civil que solicitam novos desenvolvimentos nas técnicas de construção e nos materiais aplicados. As barras de aço nervuradas são um dos principais produtos empregados na produção de peças e estruturas de concreto armado sendo usadas largamente por todo o mundo. A otimização da aplicação final, a necessidade de manter baixos custos de produção e atender a combinação de alta resistência com grande ductilidade em um material com características de soldabilidade destinados a armaduras de concreto armado, se tornou um grande desafio para os produtores de vergalhões para a construção civil. Aplicando a tecnologia desenvolvida ao longo dos últimos 50 anos, este trabalho oferece a alternativa de se empregar aços microligados ao vanádio e nióbio para a produção em laminadores de alta produção de rolos de vergalhões capazes de atender a indústria da construção civil nos mais rigorosos atributos solicitados. Os experimentos foram realizados em escala industrial testando aços com faixa de 0,14 porcento a 0,20 porcento de vanádio e até 0,04 porcento de nióbio. Os resultados atendem as normas mais exigentes no mercado mundial. / [en] The development of microalloyed steel for the production of reinforcement bars (rebar) seeks to achieve the modernization of reinforced concrete structures and streamline industrialization in civil construction that demands new developments in techniques and applied materials. Rebar is one of the main products used in the production of reinforced concrete all over the world. The optimization of the final application and the necessity to keep production low costs while attempting to combine high resistance with great ductility in a material with weldability characteristics, became a great challenge for the producers of rebars. Applying the technology developed throughout the last 50 years, this work offers the alternative of using vanadium and niobium microalloyed steel to produce large quantities of rebars in rolling mills. Upon completion these rebar are used in coils capable of meeting the most rigorous demands of the civil construction industry. The experiments made in an industrial environment, applied steels with 0.14 percent to 0.20 percent of vanadium and up to 0.04 percent of niobium. The results met the most demanding standards in the world-wide market.
34

Contribution à la compréhension du couplage thermomécanique en laminage à chaud sur l’évolution des défauts de coulée / Contribution at the comprehension of thermomechanical coupling on the evolution of the casting defect during rolling

Chevalier, Damien 21 December 2016 (has links)
Le laminage est un procédé de mise en forme à chaud permettant d’obtenir des barres de différents diamètres en partant de blooms issus de la coulée continue. Dans les bruts de coulée se répartissent des inclusions qui sont de natures, de formes et de tailles différentes. Le laminage va permettre de réduire le diamètre de la barre et d’agir sur la microstructure du matériau, notamment, en fragmentant et dispersant les inclusions. L’objectif des travaux de thèse est de contribuer à la compréhension des effets du chargement thermomécanique sur l’évolution des défauts de coulée en laminage. Vu la dimension des installations, les investigations expérimentales directes sur les moyens industriels ne sont pas envisageables. L’idée développée dans les travaux de thèse concerne la mise en place et la validation d’un essai de caractérisation à échelle réduite reproduisant le chemin thermomécanique subi par la matière au cours du laminage. Pour ce faire la ligne de laminage industrielle est modélisée afin d’obtenir le chargement thermomécanique de la barre au cours du laminage. Seules les sollicitations ayant un rôle majeur sur le comportement des défauts sont reproduites. Un essai dit de « forgeage libre » a ainsi été conçu, réalisé, mis en place sur les moyens de mise en forme de la plateforme VULCAIN de l’ENSAM. L’essai a été utilisé avec des défauts artificiels présentant des similarités comme la malléabilité avec les défauts réels. Une campagne expérimentale paramétrique a été menée sur les différents types de défauts. Les échantillons forgés ont été analysés par des méthodes non destructives comme les ultrasons, la radiographie et la tomographie X. Ces analyses ont permis de suivre le comportement du défaut et d’observer certains phénomènes mis en évidence dans la littérature comme l’apparition de cavité à l’interface défaut-matrice / Rolling is a hot forming process dedicated to manufacture bars with different diameters. The initial product is a bloom from the continuous casting. The bloom contains inclusions which have different forms, sizes and distributions. The rolling reduces the diameter of the bar and acts on the material microstructure by fragmenting and dispersing the inclusions. The aim of the thesis work is to understand the behavior of the inclusions with the rolling thermo mechanical loading effects. The direct investigations on the rolling mill are not possible because of the size of the installations. To address this problem, the solution is to develop and validate a small scale characterization test reproducing the thermo mechanical loading of the rolled bar. To achieve this, the rolling mill is modeled. Only the solicitations which have a major role on the behavior of the defects are reproduced. An open-die forging test is designed, manufactured and implemented on the VULCAIN installation of the ENSAM. The artificial defects which have a similar malleability to the real defects are integrated into the sample. A parametric experimental campaign has been conducted on the different defects. The forged samples have been analyzed with non-destructive methods such as ultrasound, radiography and tomography. These analyses allowed to follow the behavior of the defects and to observe certain phenomena illustrated in the literature such as the emergence of a cavity on the defect-matrix interface.
35

[en] FRAMEWORK FOR IMPLEMENTATION OF AUTONOMOUS MAINTENANCE WITH THE HUMAN, TECHNOLOGICAL AND ORGANIZATIONAL (HTO) APPROACH / [pt] FRAMEWORK PARA IMPLEMENTAÇÃO DA MANUTENÇÃO AUTÔNOMA COM A ABORDAGEM DAS DIMENSÕES HUMANA, TECNOLÓGICA E ORGANIZACIONAL (HTO)

PAULO CEZAR LOURES 30 April 2021 (has links)
[pt] A Manutenção Autônoma (MA) é parte de uma estratégia de manutenção que se centra na relação homem-máquina para efetuar de forma eficaz a limpeza, lubrificação, inspeção e pequenos reparos. Quando devidamente implementada, a MA pode melhorar significativamente a produtividade e a qualidade, bem como reduzir os custos, portanto é uma importante área da Gerência de Operações (OM). No entanto, a indústria tem sido desafiada com inúmeras barreiras para implementar com sucesso a MA, e o meio acadêmico pouco tem feito para ajudar a indústria a este respeito. Esta dissertação aborda essa atual lacuna entre pesquisa e prática, tendo como objetivo principal desenvolver um framework para a implementação da MA com as dimensões Humana, Tecnológica e Organizacional (HTO). O trabalho baseia-se numa pesquisa-ação, conduzida no âmbito de um estudo longitudinal, num processo de laminação de tiras a quente de uma usina siderúrgica. A adoção da abordagem HTO por pesquisadores da OM tem sido conduzida com sucesso em diferentes casos e está bem documentada na literatura. No entanto, o autor sugere que esta é a primeira pesquisa a utilizar esta abordagem dentro da MA. Os resultados da pesquisa indicam a aderência das dimensões HTO para corresponder aos desafios da implementação da MA e reforçar a necessidade de uma perspectiva holística e combinada destas dimensões para o desenvolvimento empresarial, resultando em ganhos de natureza quantitativa e qualitativa e que quatorze lições foram aprendidas com implicações práticas imediatas. Os gestores da indústria podem fazer um balanço das lições aprendidas no âmbito desta pesquisa-ação e utilizar o framework oferecido para ajudar à implementação com sucesso da MA nas suas operações industriais. / [en] Autonomous Maintenance (AM) is part of a maintenance strategy that focuses on the man-machine relationship to effectively carry out cleaning, lubrication, inspection and minor repairs. When properly implemented, AM can significantly improve productivity and quality, as well as reduce cost, therefore, it is an important area of operations management (OM). However, the industry has been challenged with numerous barriers to successfully implement AM and the academy has done little to help industry in this regard. This paper addresses this current research practice gap by offering as its main goal a framework for implementation of AM with the Human, Technological and Organizational (HTO) dimensions. It builds upon an action-research conducted within a longitudinal study in a rolling mill production process. The adoption of the HTO approach by OM scholars has been successfully conducted in different cases and is well documented in the literature. However, the author suggests that this is the first research to use this approach within AM. The research findings indicate the adherence of the HTO dimensions to match the AM implementation challenges and reinforce the need for a holistic and combined perspective of these dimensions for business development, resulting in gains of both a quantitative and qualitative nature and that fourteen lessons were learned with immediate practical implications. Practitioners can take stock of the lessons learnt within this action-research and the offered framework to aid the successful implementation of AM in their industrial operations.
36

Технологические режимы прокатки на 3-х валковом непрерывном стане : магистерская диссертация / The technological conditions of rolling on a 3-roll continuous rolling mill

Kislyi, G. V., Кислый, Г. В. January 2014 (has links)
Ways of rolling tubes on a continuous rolling mill considered in the work. Overview of three-roll continuous rolling mills are given. Technology for the production of pipes for pipe unit with 3 roller stand continuous mill developed. The geometric model of the process by scanning the tube sheet is constructed. Determination of the amount of deformation is made. Kinematically possible velocity field is constructed. Examples of calculations of a table rolling and modes of compression on a continuous three-roll mill is shown. / В работе рассмотрены способы прокатки труб на непрерывном стане, проведен обзор трехвалковых оправочных станов. Приведена технология производства труб на ТПА с 3-х валковой клетью непрерывного стана. Построена геометрическая модель обжатия путем развертки трубы в лист и проведено определение размера очага деформации. Построено кинематически-возможное поле скоростей. Приведены примеры расчетов таблицы прокатки и режимов обжатия на непрерывном трехвалковом стане.
37

3D-Simulation und Planung von Anlagen der Hütten- und Walzwerkstechnik

Oppermann, Ingo 11 May 2009 (has links) (PDF)
In der Präsentation werden typische Engineeringaufgaben präsentiert, die mit modernen IT-Werkzeugen erledigt werden. Es wird auf die Einführung und die Durchgängigkeit eines 3D-CAD-Systems eingegangen und gezeigt, wie mit diesem System Simulations- und Prozesskettenthemen in der Praxis bei der SMS Siemag AG behandelt werden. Ebenfalls anhand von Beispielen wird die Thematik der großen Baugruppen und der Anlagenplanung im 3D-Engineering dargestellt.
38

[en] NEW MODEL FOR THE SLAB STACK SHUFFLING PROBLEM INSIDE THE SLAB YARD OF A HRM / [pt] UMA NOVA PROPOSTA PARA O PROBLEMA DE REMANEJAMENTO DE PLACAS EM UM PÁTIO PARA ATENDIMENTO DE UMA LAMINAÇÃO

EDSON FELIPE AMADO FERNANDES 18 October 2018 (has links)
[pt] O presente trabalho desenvolve um novo modelo para um problema logístico de remanejamento de placas entre pilhas em um Pátio de Placas de uma Laminação, típico da indústria siderúrgica. Esta abordagem inclui uma nova característica que indica o destino das placas remanejadas. Uma nova metodologia de decisão altera sensivelmente o escopo do problema e traz um novo conceito: o balanço entre a escolha ótima das placas e o possível destino das placas remanejadas, ou seja, deve-se pesar a escolha da placa a ser laminada juntamente com a possibilidade de um bom remanejamento das placas que estão acima da mesma. Esse modelo não linear é linearizado por técnicas de linearização e resolvido através de programação linear inteira. Com isso, o estudo apresenta uma redução no tempo médio de manuseio de placas (TMM) de 5 minutos por placa laminada encontrado na literatura existente, para menos de 4 minutos. Finalmente o modelo proposto incentiva a construção de uma ferramenta de gestão que possa resolver o problema SSS em situações práticas do dia-a-dia através de redução de custo de operação como forma de viabilizar o investimento nesta ferramenta. / [en] This work develops a new model for a typical logistic problem in the steel industry known as slab stack shuffling problem inside a Slab Yard of a Rolling Mill. This new approach includes a new feature that indicates the destination stacks of shuffled slabs. A new decision methodology changes significantly thescope of the problem and introduces a new concept: the balance between optimal choice of the rolled slabs and possible destinations for shuffled slabs which means it must weigh the choice of the slab to be rolled engaged with a low cost shuffle operation for the slabs that are above the chosen slab. This nonlinear model is linearized through specific modeling techniques and solved by integer linear programming. Thus, this work shows a reduction in average handling time (TMM) from 5 minutes per rolled slab found in the literature, to less than 4 minutes. Finally, the proposed model encourages the construction of a management tool that can solve the SSS problem in practical daily situations through operating costs reduction as a payback of investment in this tool.
39

3D-Simulation und Planung von Anlagen der Hütten- und Walzwerkstechnik

Oppermann, Ingo 11 May 2009 (has links)
In der Präsentation werden typische Engineeringaufgaben präsentiert, die mit modernen IT-Werkzeugen erledigt werden. Es wird auf die Einführung und die Durchgängigkeit eines 3D-CAD-Systems eingegangen und gezeigt, wie mit diesem System Simulations- und Prozesskettenthemen in der Praxis bei der SMS Siemag AG behandelt werden. Ebenfalls anhand von Beispielen wird die Thematik der großen Baugruppen und der Anlagenplanung im 3D-Engineering dargestellt.
40

Effects of mill rotational speed on the batch grinding kinetics of a UG2 platinum ore

Makgoale, Dineo Mokganyetji 11 1900 (has links)
In this study, the effect of speed was investigated on the breakage rate of UG2 platinum ore in a batch mill of 5 dm3 and 175 mm internal diameter. One size fraction method was carried out to perform the experiment. Five mono-sized fractions in the range of 1.180 mm to 0.212 mm separated by √2 series interval were prepared. The fractions were milled at different grinding times (0.5, 2, 4, 15 and 30 min) and three fractions of mill critical speed were considered (20%, 30%, and 40%). The target of critical speed below 50% was due to the need of lower energy consumption in milling processes. The selection and breakage function parameters were determined and compared for fractions of critical speed. First the grinding kinetics of the ore was determined and it was found that the material breaks in non-first order manner. Thereafter, effective mean rate of breakage was determined. It was found that the rate of breakage increased with increase of mill speed and optimum speed was not reached in the range of chosen mill speed fractions. Again the rate of breakage was plotted as a function of particle size, the optimum size was 0.8 mm when milling at 30% critical speed. As for 20% and 30% optimum size was not reached. The selection function parameters estimated at 30% critical speed were 𝑎0 = 0.04 min−1 , 𝛼 = 1.36, 𝜇 = 0.9 mm, and Λ = 3. Breakage function parameters were determined and was noticed that the material UG2 platinum ore is non-normalised, i.e. Φ value was changing from 0.25 to 0.90 depending on feed size and mill speed. The parameters 𝛽 and 𝛾 were constant at 7.3 and 1.17 respectively. / College of Science, Engineering and Technology / M. Tech. (Chemical Engineering)

Page generated in 0.0403 seconds