Ovaldrehen ist eine alte Drechseltechnik.<br/>Sie wurde seit einigen Jahren durch neue Ovaldrehmaschinen wiederbelebt. Diese Maschinen und ihr Zubehör sowie ihr Gebrauch werden beschrieben. Die Grundlagen bilden getriebetechnische und geometrische Analysen. <br/>Eine Galerie ovalgedrehter Gebrauchsgegenstände zeigt die Vielfalt der Anwendungsmöglichkeiten.<br/>Am Schluss steht ein Verzeichnis relevanter Literatur, Videos und Adressen im Internet und von Ovaldreh-Praxen.

Ovalturning is an ancient woodturning art, recently revived by new ovalturning lathes designed and tested by the author. These lathe, their accessories and their usage and application are described in detail. The fundaments are kinematical mechanism analysis and the ellipse geometry. A gallery of oval turned items for usage shows partially the variety of ovalturning application. At the end is given a list of relevant literature, videos and addresses in the internet and of ovalturning practioners and schools. Second edition

This research project is based upon the assumption that humanity is passing through a period of great transition, or “Great Turning,” in which we have a critical opportunity to pass from a destructive “industrial growth society” to a “life-sustaining society” (Macy and Brown, 1998). I argue that the current scale of social, political, environmental, economic, psychological, and spiritual challenges reflects an underlying “disconnect disorder” (Arabena, 2006), and that these combined external and internal crises present an opportunity for widespread transformative learning and a collective shift. My core hypothesis is that this transition depends on humanity’s ability to engage in a dual process of individual and collective transformation through remembering our connections with ourselves, with one another, with the natural world, and with a sense of purposeful engagement in the world. I investigate this hypothesis through an in-depth, relational study of the Ecology of Leadership program (EOL) at the Regenerative Design Institute (RDI) in Bolinas, California, an organization that aims to “serve as catalyst for a revolution in the way humans relate to the natural world.” The Ecology of Leadership represents a unique model of transformative adult education that incorporates the principles of “inner permaculture” and regenerative design to support participants in cultivating personal and collective transformation. I introduce a “relational” theory and methodological approach, which centralizes Indigenous and ecological principles of relationship, respect, reciprocity, and regeneration. Using interviews (p=20), surveys (p=409), arts-based data (p=12), sharing circles (p=8), and participatory research, I integrate personal and participant narratives together with images, graphics, poems, and practices to bring this case study of the Ecology of Leadership to life. I also advocate for a new model of “regenerative research,” in which the research itself is life-giving and contributes to the healing, transformation, and regeneration of the researcher, the community of research, and the whole system. Based upon my interactions, observations, and interviews in the EOL program and my reflections and supportive research, I conclude by articulating the “Ecology of Transformation,” a holistic model for transformation that incorporates inner and outer change with practices for reconnection to oneself, the natural world, and the village.

Classical orthogonal and oblique cutting are the fundamental material removal or machining processes to which other practical machining processes can be related in the study and modelling of the machining processes. In the last century, a large amount of research and development work has been done to study and understand the various machining processes with a view to improving the processes for further economic (cost and productivity) gains. However, many aspects of the cutting processes and cutting performance remains to be fully understood in order to increase the cutting capability and optimize the cutting processes; in particular, there is little study to understand the effects of the inevitable tool wear on the machining processes. This thesis includes an extensive literature review on the mechanics of cutting analysis. Considerable work has been carried out in past decades on the fundamental analysis of 'sharp' tool cutting. Although some work has been reported on the effects of tool flank wear on the cutting performance, there is a general lack of the fundamental study of the effects of the flank wear on the basic cutting or chip formation process. It has been well documented that tool flank wear results in an increase in the cutting forces. However, it was not known if this force increase is a result of the change in the chip formation process, and/or the rubbing or ploughing forces between the tool flank and the workpiece. In work carried out since the early 1980s, the effects of the so-called edge forces have been considered when the tool is not absolutely sharp. Little has been reported to further develop fundamental cutting theories to understand applications to more relevant the practical situation, i.e. to consider the tool wear effects. Based on the findings of the literature review, an experimental investigation is presented in the first part of the thesis to study the effects of tool flank wear on the basic cutting or chip formation process by examining the basic cutting variables and performance in the orthogonal cutting process with tool flank wear. The effects of tool flank wear on the basic cutting variables are discussed by a comprehensive analysis of the experimental data. It has been found that tool flank wear does not affect the basic cutting variables (i.e. shear angle, friction angle and shear stress). It is therefore deduced that the flank wear does not affect the basic chip formation process in the shear zone and in the tool-chip interface. The study also finds that tool flank wear causes an increase in the total cutting forces, as can be expected and such an increase is entirely a result of the rubbing or ploughing forces on the tool wearland. The significance of this finding is that the well-developed machining theories for 'sharp' tools can be used in modelling the machining processes when tool flank wear is present, rather than study the machining process and develop machining theories from scratch. The ploughing forces can be modelled for incorporation into the overall cutting force prediction. The experimental study also allows for the forces on the wearland (or wearland force) and edge forces to be separated from the total measured forces. The wearland force and edge force models are developed in empirical form for force prediction purpose. In addition, a database for the basic cutting variables or quantities is established for use in modelling the cutting forces. The orthogonal cutting force model allowing for the effects of flank wear is developed and verified by the experimental data. A comprehensive analysis of the mechanics of cutting in the oblique cutting process is then carried out. Based on this analysis, predictive cutting force models for oblique cutting allowing for the effects of flank wear are proposed. The wearland force and edge force are re-considered by analysing the oblique cutting process and the geometrical relation. The predictive force models are qualitatively and quantitatively assessed by oblique cutting tests. It shows that the model predictions are in excellent agreement with the experimental data. The modelling approach is then used to develop the cutting force models for a more general machining process, turning operation. By using the concept of an equivalent cutting edge, the tool nose radius is allowed for under both orthogonal and oblique cutting conditions. The wearland forces and edge forces are taken into consideration by the integration of elemental forces on the tool flank and the cutting edge, respectively. The cutting forces in turning operations are successfully predicted by using the basic cutting quantity database established in the orthogonal cutting analysis. The models are verified by turning operation tests. It shows that the model predictions are in excellent agreement with the experimental results both qualitatively and quantitatively. The major findings, research impacts and practical implications of the research are finally highlighted in the conclusion. The modelling approach considering the flank wear effects in the classical orthogonal and oblique cutting and turning operations can be readily extended to other machining operations, such as drilling and milling.

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references.

The aim of this study was to understand how gang members desist from their gangs and which role authorities have in the process. More specifically the aim was to discover turning points and find out how the former gang members themselves look upon the contact with authorities, for example social services. This study was based on five interviews and two autobiographies with former gang members. The interviews took place in a organisation for former offenders in Sweden and the choice of autobiographies was based on the purpose of this study. As the results showed, the most common turning points was social bonds, fear of prison, disappointment and traumatic events or experiences. Authorities did not have any impact on the decision of leaving the gang. Former gang members also indicated that they had negative experiences with the authorities. Based on the results of this study suggestions for improvement have emerged. Authorities need to have experienced employees, knowledge about gang members, have a flexible work method and a positive approach.

Made available in DSpace on 2016-12-23T14:00:38Z (GMT). No. of bitstreams: 1 FOLHA DE ROSTO A SUMARIO.pdf: 114961 bytes, checksum: 8ff6dbc0edc8b0f0942b2113ba85fdfd (MD5) Previous issue date: 2008-05-01 / Leading indicators are a method based on the examination of a cycle as an empirical phenomenon; the concept of business cycles appeared in middle of the 20th century by Wesley Mitchell and Arthur Burns. It is one technique that searchs to anticipate the behavior of one given serie (reference). Diverse methods exist for its construction. In this study it is considered a construction of an indicator for Produção Industrial Brasileira (Brazilian Industrial Production) with the objective of calculating the probabilities of the turning point. For this, the series have been filtered and standardized. The Granger criterion gave basis for the selection. A balance with cross correlograms of the chosen sequencies (series) occurs for the composition of the indicator and for the calculation of the probability of reversion the methodology of Neftçi (1982) was used. Around 290 sequencies (series) were analyzed and only 9 were selected for the construction of the indicator. Some samples periods of time have been studied from January of 1992 to December of 2006 for the calculation of the probabilities, these also have been calculated by another method (probit) to compare with the methodology of Neftçi. The results demonstrate the great utility of this tool for forecasting of the cyclical movements of economic series. It is a technique that can be used to help with public politics and private policy making. / Indicadores antecedentes é um método baseado no exame do ciclo como um fenômeno empírico; surgiu do conceito de ciclos de negócio em meados do século XX por Wesley Mitchell e Arthur Burns. É uma técnica que busca antecipar o comportamento cíclico de uma dada série (referência). Existem diversos métodos para sua construção. Neste estudo propõe-se a construção de um indicador para a Produção Industrial Brasileira com o objetivo de calcular as probabilidades de mudança de fase ou reversão dos ciclos (turning point). Para isto as séries foram filtradas e padronizadas. A seleção se deu por um critério de causação (Causalidade de Granger). Para a composição do indicador, foi realizada uma ponderação com a correlação cruzada das séries escolhidas devidamente defasadas e, por fim, para o cálculo da probabilidade de reversão foi utilizada a metodologia de Neftçi (1982). Analisou-se cerca de 290 séries e somente nove foram selecionadas para a construção deste indicador. Estudaram-se alguns períodos amostrais, entre 01/1992 a 12/2006, para o cálculo das probabilidades, estas também foram calculadas por outro método (probit) para confronto com a metodologia de Neftçi. Os resultados demonstram a grande utilidade de tal ferramenta para previsão dos movimentos cíclicos de séries econômicas. É uma técnica que pode ser utilizada como orientação para políticas públicas e decisões privadas.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The chip formation is influenced by several cut parameters which also affect the forces, tensions, powers and temperatures generated during the machining process. Although they have been studied for more than 100 years, still today, the involved mechanisms of deformation are not totally know, due to the fact that the chip formation involves high temperatures and high levels of deformation. This research aims at studying the basic process of chip formation, as well as the influence of the main cut parameters such as cutting speed, feed rate, cutting fluid, tool coating and machined material, besides determining the force of residual cut for ABNT 1045 steel. The inquiry was based on the classification of the chips concerning their type and form, thicknesses values, shear angles, stresses degree and in the monitoring of the cutting forces. Micrographs and measurement of the chips microhardness were made in order to achieve a detailed structural analysis. The results found have shown that the parameters and analyzed conditions really influenced the formation of the chips, being the feed rate more significant than the cutting speed. The tool coating and the cutting fluid had a great influence on the chip formation as well as on the cutting forces during the machining of ABNT 1045 steel and nodular casting iron. The residual cutting force for the ABNT 1045 steel varied between 45 N and 52N. / A formação do cavaco é influenciada por vários parâmetros de corte que afetam também as forças, tensões, potências e temperaturas geradas durante a usinagem. Apesar de ser estudado a mais de 100 anos, ainda hoje os mecanismos de deformação envolvidos não são totalmente conhecidos. Isto se deve ao fato da formação do cavaco envolver grandes temperaturas e altíssimas taxas de deformação. Este trabalho pretende estudar o processo básico de formação do cavaco bem como a influência dos principais parâmetros de corte, tais como velocidade de corte, avanço, fluído de corte , revestimento da ferramenta e material usinado, além de determinar a força de corte residual para o aço ABNT 1045. A investigação foi baseada na classificação dos cavacos quanto ao seu tipo e forma, valores das espessuras, dos ângulos de cisalhamento, grau de recalque e no monitoramento das forças de corte. Foram feitas micrografias e medição da microdureza dos cavacos para uma análise estrutural mais detalhada. Os resultados encontrados através dos experimentos mostraram que os parâmetros e condições analisadas realmente influenciam na formação dos cavacos, sendo que o avanço foi mais significativo que a velocidade. O revestimento e o fluído tiveram grande influência tanto na formação do cavaco como nas forças de corte durante a usinagem do aço ABNT 1045 e do ferro fundido nodular. A força de corte residual para o aço ABNT 1045 variou entre 45 N e 52N. / Mestre em Engenharia Mecânica

As empresas não mais podem pensar em desenvolvimento econômico sem a paralela preservação do meio-ambiente e do benefício mútuo da sociedade. É importante que as condições econômicas e sociais sejam melhoradas ao longo do tempo, sem exceder a capacidade de suporte do planeta. As indústrias podem contribuir para melhorar esse cenário aplicando uma gestão sustentável de manufatura, uma vez que estes são um dos principais agentes causadores de impactos. No entanto, para que consigam aprimorar a sustentabilidade de seus processos, é indispensável, antes de tudo, conhecer o seu real desempenho. O presente trabalho tem como objetivo principal desenvolver um método estruturado e simples para a avaliação de desempenho em sustentabilidade de processos de manufatura, permitindo a construção de relatórios de sustentabilidade mais precisos, periódicos e que venham a apoiar o processo de tomada de decisão gerencial. Embora modelos para a avaliação de desempenho em sustentabilidade tenham sido apresentados nos últimos anos, como o guia GRI, estes ainda carecem de critérios e regras para realizar análises mais precisas e integradas. O método proposto pode ser aplicado em dois processos de manufatura distintos, comprovando a sua eficácia e robustez. Ele é usado para analisar e comparar o desempenho em sustentabilidade de dois processos de usinagem, Retificação e Torneamento de Metais Endurecidos. Esses processos concorrem entre si em algumas faixas de atuação, tornando difícil a decisão sobre qual dos dois processos é o ideal para a produção de determinadas peças. Por meio do trabalho, foi possível comprovar a superioridade do processo de retificação em termos de ganhos econômicos, com a contrapartida de pior desempenho ambiental / Companies can no longer consider economical development without the parallel preservation of the environment and mutual benefit of the society. It is important that the economic and social conditions are improved over time, without exceeding the planet carrying capacity. Industries can contribute to improve this scenario by using cleaner and more efficient technologies, since they are one of the main sources of impacts. However, for them to improve their processes sustainability, it is essential to use an assessment tool which is able to evaluate their performance properly. The main goal of this work is to provide a structured and simple method for assessing sustainability performance of manufacturing processes, allowing the construction of more accurate and frequent sustainability reports, that may support the managerial decision making process. Although sustainability performance assessment models have been presented in recent years, as the GRI, there are still a lack of criteria and rules for carrying out more accurate and integrated assessments. The proposed method was able to be applied in two different manufacturing processes assessments, proving its effectiveness and robustness. It was used to analyze and compare the sustainability performance of two machining processes, grinding and hard turning. These processes compete with each other on some applications, making it difficult to decide which of the two processes is ideal for the production of certain parts. Through the study, it is demonstrated the grinding process superiority in terms of economic gains, at the cost of a higher environmental burden

Orientador: Amauri Hassui / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-12T23:13:39Z (GMT). No. of bitstreams: 1 RossiNeto_Eneas_M.pdf: 13972971 bytes, checksum: 1c7b89f4fdc28248118cde9b4b90db25 (MD5) Previous issue date: 2009 / Resumo: Neste trabalho procurou-se estudar e desenvolver um processo inédito de usinagem para ser implementado na manufatura dos cilindros automotivos, componentes muito importantes utilizados nos motores de automóveis que possuem bloco de alumínio. São poucos e conhecidos os fabricantes do segmento automotivo que fabricam este produto, sendo que, até então, todos utilizavam operação de mandrilamento para usinagem do diâmetro interno da camisa. Entre outras vantagens, este trabalho propõe aumentar a produtividade de maneira significativa, atendendo todas as especificações técnicas do produto. A operação de mandrilamento foi substituída por torneamento interno, utilizando um centro de torneamento com sistema de carga e descarga integrado, ferramentas de corte e dispositivos de fixação especiais e estratégias de usinagem diferenciadas. As camisas para cilindro são fabricadas de ferro fundido cinzento centrifugado, um material extremamente abrasivo que requer cuidados na sua manufatura. Após o desenvolvimento completo do processo e prévios ensaios de usinagem para definição das premissas, utilizou-se uma metodologia objetiva para otimização do processo proposto, realizada no ambiente fabril, considerando todas as variáveis encontradas nas condições reais de produção. Os resultados obtidos mostraram que os insertos de metal duro com cobertura apresentaram um melhor desempenho que os insertos de cerâmica à base de nitreto de silício e de óxido de alumínio na aplicação em estudo, sendo constatado também as melhores condições de corte para o torneamento interno de cilindros automotivos de ferro fundido cinzento centrifugado / Abstract: This investigation describes and shows an unprecedented machining process to be used for manufacturing cylinder liners, which are very important parts used in aluminum engine blocks for automobiles. There are few known companies that manufacture this kind of component, and until now, all of them use a boring process to machine the internal diameter of the cylinder liner. Among other advantages, this investigation intends to increase significantly productivity, while respecting all technical specifications of the product. The boring process was replaced by internal turning, which uses a turning center with load/unload system, special cutting tools and clamp devices, as well as audacious machining strategies. The cylinder liners are made from centrifuged gray cast iron, an extreme abrasive material that needs special care during its machining process. After the complete development of the process and tryouts to define the preliminary data, it has been used an objective methodology to optimize the proposed process, developed on the shop floor, considering all the variables found in real production conditions. The investigation results shown the carbide inserts had better performance than the silicon nitride and aluminum oxide ceramic inserts in this studied application, evidencing the best cutting conditions to internal turning for cylinder liners made of centrifuged gray cast iron / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica