127 research outputs found
Proposta de diretrizes para o projeto para manufatura enxuta
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-graduação em Engenharia MecânicaA implementação da Manufatura Enxuta tem tido uma importante participação na busca pelo aumento de eficiência e produtividade de indústrias que enfrentam uma competição de mercado acirrada, como a automotiva. A Manufatura Enxuta encontra seus principais alicerces nas boas práticas desenvolvidas pelas indústrias automotivas japonesas no final da segunda grande guerra, na busca por alta qualidade, baixos custos de transformação, menores lead times e maior flexibilidade. Devido à alta competitividade em diversos setores industriais, particularmente no automotivo, existe um grande esforço pela aplicação da Manufatura Enxuta em níveis cada vez mais profundos. É de fácil verificação que o processo de desenvolvimento de produtos tem forte impacto na eficácia e amplitude de sua aplicação. Por outro lado, verifica-se a falta de elementos para o desenvolvimento de produtos que contribuam com a implantação da abordagem enxuta, buscando eliminar desperdícios na etapa de manufatura a partir das fases iniciais do processo de desenvolvimento de produtos. A preocupação em desenvolver produtos que maximizem características específicas, através da utilização da Engenharia Simultânea, fez surgir o Projeto para Manufatura (DFM). Até o momento, nenhuma ferramenta conseguiu oferecer subsídios suficientes para equipes de desenvolvimento, em sua tarefa de desenvolver produtos que venham a contribuir com a implantação da Manufatura Enxuta em sua totalidade. Da mesma forma, a Engenharia Simultânea não tem sido utilizada de maneira apropriada na busca pelo envolvimento da equipe de desenvolvimento com a Manufatura Enxuta. O presente estudo busca desenvolver e sugerir, na forma de diretrizes para o Design for Lean Manufacturing (DFLM), uma sistematização das melhores práticas para o desenvolvimento de produtos com foco na implantação da Manufatura Enxuta. Estas diretrizes foram reunidas levando-se em consideração a identificação de requisitos pertinentes à implementação da Manufatura Enxuta, durante o processo de projeto. As diretrizes propostas foram aplicadas num estudo de caso junto a uma empresa do setor automobilístico, e os resultados mostraram a relativa facilidade de aplicação das mesmas e também ganhos significativos em termos da redução do lead time do processo produtivo. Lean Manufacturing approach implementation has had an important participation in productivity improvement in first-rate industries. This approach came from the gathering of the best practices used by the Japanese automotive industries as of the end of the Second World War targeting simultaneously high quality, low costs, lower lead time and enhanced flexibility. Due to high competitiveness in first rate industries, mainly automotive, there is a great effort in applying Lean Manufacturing approach in deeper levels. It is not difficult to verify, that product concept has had an important role on its efficacy, and while on the other hand, one can verify a lack of elements for a proper development of products with focus on Lean Manufacturing approach. Concern to design products that maximize specific characteristics through utilization of Simultaneous Engineering gave birth to DFX tools such as Manufacture (DFM). To this date, no DFX tool has offered enough subsidies to the design team in its task of generating products that will contribute with the implementation of Lean Manufacturing in its entirety, also has Simultaneous Engineering not been properly utilized in the job of involving the Product Design team with Lean Manufacturing approach. The present study seeks to bring forward, in the form of a set of guidelines called Design for Lean Manufacturing (DFLM), the systematization of the best supporting practices for the development of products with focus on the implementation of Lean Manufacturing through Simultaneous Engineering. These guidelines have been put together considering the identification of product requisites pertinent with the implementation of Lean Manufacturing. The proposed systematization focuses conceptual design and detailed design phases of Product Development Process. Proposed guidelines were applied in a case study placed in an automotive facility sector and results indicated they were relatively easy to use as well as significant gains regarding productive process lead time were achieved
Spurenanalyse von Aktiniden in der Umwelt mittels Resonanzionisations-Massenspektrometrie
No full textIn dieser Arbeit wurde die Methode der resonanten Ionisation von neutralen Atomen mittels Laserstrahlung auf die leichten Aktinide Thorium, Uran, Neptunium und Plutonium angewendet und für die Ultraspurenanalyse optimiert. Der empfindliche Nachweis dieser Aktinide stellt eine Herausforderung für die Beobachtung und Bestimmung von radioaktiven Verunreinigungen aus kerntechnischen Anlagen in der Umwelt dar. In einem für diese Untersuchungen entwickelten Quadrupolmassenspektrometer konnte durch Resonanzionisationsspektroskopie jeweils eine Reihe unbekannter Energiezustände in der Elektronenhülle des neutralen Atoms der oben genannten Aktinide identifiziert, sowie effiziente Anregungsschemata für die resonante Ionisation entwickelt und charakterisiert werden. Durch die verwendete in-source-Ionisation, die aufgrund der guten Überlagerung von Laserstrahlung und Atomstrahl eine hohe Nachweiseffizienz gewährleistet, konnten diese Untersuchungen bereits mit einem, für Radionuklide notwendigen, geringen Probeneintrag erfolgen. Die resonante Ionisation erlaubt durch die selektiven resonanten Prozesse eine Unterdrückung unerwünschter Kontaminationen und wurde auf den analytischen Nachweis von Ultraspurengehalten in Umweltproben, sowie die Bestimmung der entsprechenden Isotopenzusammensetzung optimiert. Durch die effiziente in-source-Ionisation mit leistungsstarker gepulster Laserstrahlung, konnten Nachweiseffizienzen im Bereich von bis zu 1% erreicht werden. Dabei wurden für Plutonium in synthetischen Proben, aber auch in ersten Umweltproben, Nachweisgrenzen von 10^4-10^5 Atomen erzielt. Die Verwendung spektral schmalbandiger Dauerstrichlaser und eine Ionisation transversal zum frei propagierenden Atomstrahl ermöglicht durch Auflösung der Isotopieverschiebung eine hohe Selektivität gegenüber dominanten Nachbarisotopen, wohingegen die Ionisationseffizienz deutlich abnimmt. Hiermit konnte für das Ultraspurenisotop U-236 eine Nachweisgrenze bis hinab zu 10^-9 für das Isotopenverhältnis N(U-236)/N(U-238) bestimmt werden.In this work the resonant ionization of neutral atoms using laser radiation was applied and optimized for ultra-trace analysis of the actinides thorium, uranium, neptunium and plutonium. The sensitive detection of these actinides is a challange for the monitoring and quantification of radioactive releases from nuclear facilities. Using resonance ionization spectroscopy combined with a newly developed quadrupole-mass-spectrometer, numerous energy levels in the atomic structure of these actinides could be identified. With this knowledge efficient excitation schemes for the mentioned acinides could be identified and characterised. The applied in-source-ionization ensures for a high detection efficiency due to the good overlap of laser radiation with the atomic beam and allows therefore for a low sample consumption which is required for the analysis of radio nuclides. The selective excitation processes in the resonant ionization method supresses unwanted contaminations and was optimized for analytical detection of ultra-trace amounts in environmental samples as well as for determination of isotopic compositions. The efficient in-source-ionization combined with high power pulsed laser radiation allows for detections efficiency up to 1%. For plutonium detection limits in the range of 10^4 - 10^5 atoms could be demonstrated for synthetic samples as well as for first environmental samples. The usage of narrow bandwidth continuous wave lasers in combination with a transversal overlap of the laser radiation and the free propagating atomic beam enable for resolving individual isotopic shifts of the reosnant transitions. This results in a high selectivity against dominant neighboring isotopes but with a signifikant loss in detection efficiency. For the ultra-trace isotope U-236 a detection limit down to 10^-9 for the isotope ratio N(U-236)/N(U-238) could be determined
Spurenanalyse von Aktiniden in der Umwelt mittels Resonanzionisations-Massenspektrometrie
No full textIn dieser Arbeit wurde die Methode der resonanten Ionisation von neutralen Atomen mittels Laserstrahlung auf die leichten Aktinide Thorium, Uran, Neptunium und Plutonium angewendet und für die Ultraspurenanalyse optimiert.
Der empfindliche Nachweis dieser Aktinide stellt eine Herausforderung für die Beobachtung und Bestimmung von radioaktiven Verunreinigungen aus kerntechnischen Anlagen in der Umwelt dar. In einem für diese Untersuchungen entwickelten Quadrupolmassenspektrometer konnte durch Resonanzionisationsspektroskopie jeweils eine Reihe unbekannter Energiezustände in der Elektronenhülle des neutralen Atoms der oben genannten Aktinide identifiziert, sowie effiziente Anregungsschemata für die resonante Ionisation entwickelt und charakterisiert werden. Durch die verwendete in-source-Ionisation, die aufgrund der guten Überlagerung von Laserstrahlung und Atomstrahl eine hohe Nachweiseffizienz gewährleistet, konnten diese Untersuchungen bereits mit einem, für Radionuklide notwendigen, geringen Probeneintrag erfolgen. Die resonante Ionisation erlaubt durch die selektiven resonanten Prozesse eine Unterdrückung unerwünschter Kontaminationen und wurde auf den analytischen Nachweis von Ultraspurengehalten in Umweltproben, sowie
die Bestimmung der entsprechenden Isotopenzusammensetzung optimiert. Durch die effiziente in-source-Ionisation mit leistungsstarker gepulster Laserstrahlung, konnten Nachweiseffizienzen im Bereich von bis zu 1% erreicht werden. Dabei wurden für Plutonium in synthetischen Proben, aber auch in ersten Umweltproben, Nachweisgrenzen von 10^4-10^5 Atomen erzielt. Die Verwendung spektral schmalbandiger Dauerstrichlaser und eine Ionisation transversal zum frei propagierenden Atomstrahl ermöglicht durch Auflösung der Isotopieverschiebung eine hohe Selektivität gegenüber dominanten Nachbarisotopen, wohingegen die Ionisationseffizienz deutlich abnimmt. Hiermit konnte für das Ultraspurenisotop U-236 eine Nachweisgrenze bis hinab zu 10^-9 für das Isotopenverhältnis N(U-236)/N(U-238) bestimmt werden.In this work the resonant ionization of neutral atoms using laser radiation was applied and optimized for ultra-trace analysis of the
actinides thorium, uranium, neptunium and plutonium. The sensitive detection of these actinides is a challange for the monitoring and quantification of radioactive releases from nuclear facilities. Using resonance ionization spectroscopy combined with a newly developed quadrupole-mass-spectrometer, numerous energy levels in the atomic structure of these actinides could be identified. With this knowledge efficient excitation schemes for the mentioned acinides could be identified and characterised. The applied in-source-ionization ensures for a high detection efficiency due to the good overlap of laser radiation with the atomic beam and allows therefore for a low sample consumption which is required for the analysis of radio nuclides. The selective excitation processes in the resonant ionization method supresses unwanted contaminations and was optimized for analytical detection of ultra-trace amounts in environmental samples as well as for determination of isotopic compositions. The efficient in-source-
ionization combined with high power pulsed laser radiation allows for detections efficiency up to 1%. For plutonium detection limits in the range of 10^4 - 10^5 atoms could be demonstrated for synthetic samples as well as for first environmental samples. The usage of narrow bandwidth continuous wave lasers in combination with a transversal overlap of the laser radiation and the free propagating atomic beam enable for resolving individual isotopic shifts of the reosnant transitions. This results in a high selectivity against dominant neighboring isotopes but with a signifikant loss in detection efficiency. For the ultra-trace isotope U-236 a detection limit down to 10^-9 for the isotope ratio N(U-236)/N(U-238) could be determined
New Developments in the Production and Research of Actinide Elements
No full textThis article briefly reviews topics related to actinide research discussed at the virtual workshop Atomic Structure of Actinides & Related Topics organized by the University of Mainz, the Helmholtz Institute Mainz, and the GSI Helmholtz Centre for Heavy Ion Research, Darmstadt, Germany, and held on the 26–28 May 2021. It includes references to recent theoretical and experimental work on atomic structure and related topics, such as element production, access to nuclear properties, trace analysis, and medical applications
A High-Resolution Optical Measurement System for Rapid Acquisition of Radiation Flux Density Maps (Poster)
No full textTo identify the power and flux density of concentrated solar radiation the Institute of Solar Research at the
German Aerospace Center (DLR - Deutsches Zentrum für Luft- und Raumfahrt e. V.) has used the camera-based
measurement system FATMES (Flux and Temperature Measurement System) since 1995. The disadvantages of low
resolution, difficult handling and poor computing power required a revision of the existing measurement system. The
measurement system FMAS (Flux Mapping Acquisition system) is equipped with state-of-the-art-hardware, is
compatible with computers off-the-shelf and is programmed in LabView. The expenditure of time for an image
evaluation is reduced by the factor 60 compared to FATMES. The new measurement system is no longer associated with
the facilities Solar Furnace and High Flux Solar Simulator at the DLR in Cologne but is also applicable as a mobile
system. The data and the algorithms are transparent throughout the complete process. The measurement accuracy of
FMAS is determined to at most +/- 3 % until now. The error of measurement of FATMES is at least 2 % higher according
to the conducted comparison tests
Clinical Ambulatory Anesthesia
No full textAmbulatory care can be a challenging setting in which to provide anesthesia – not all patients are suitable for rapid discharge post-operatively and opinions differ as to which types of surgery should be performed as day cases. This comprehensive guide delivers up-to-date, evidence-based advice on how to provide optimal anesthesia care for ambulatory surgery. Written by a leading clinical anesthesiologist, it provides clear guidance about how to handle particular patients in particular situations. The evidence and scientific knowledge for each issue are presented with reference to major studies and review papers, followed by practical advice based on the author&apos;s continuous clinical and scientific experience over 30 years. Topics include planning, equipping and staffing ambulatory units, pharmacology, basic concepts of ambulatory care, pre- and post-operative issues and current controversies. Clinical Ambulatory Anesthesia is essential reading for the clinical, postgraduate anesthesiologist as well as nurse anesthetists involved with ambulatory care.</jats:p
F. A. Hayek on the role of reason in human affairs
No full textThis-study examines the views of F. A. Hayek on the role of reason in human affairs. The author explicates certain elements of Hayekian theory that bear on this issue-his views on the nature of mind, rules, law, and cultural evolution-and discusses the characteristics of both the constructivist and critical kinds of rationalism Hayek identifies. She then examines the views of various critics who have challenged Hayek\u27s argument. She concludes that, contrary to certain critics, 1) the distinction he draws between constructivist and critical rationalism is meaningful and that the two kinds of rationalism appear to be related to certain political views; 2) whether Hayek, despite his criticism of the constructivistic conceit, should himself be considered a constructivist depends on whether one adopts a broad or narrow interpretation of constructivism; and 3) Hayek\u27s method of social criticism-what he terms immanent criticism -does provide the basis for a meaningful critical theory
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