901 resultados para Lean maintenance


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The objective was to identify determinants of uptake and maintenance of active school travel (AST) over 4 years in children aged 9 at baseline. Data from wave 1 (n=8502) and 2 (n=7479) of the Growing Up in Ireland study were analysed. At 9- and 13-years 25% and 20% engaged in AST. Children were more likely to maintain or take-up AST if they lived in an urban area. Change in distance to school influenced both maintenance and adoption of AST, with a negative impact seen for increased distance between 9 and 13 years and a positive impact seen for decreased distance. Some factors which predict uptake and maintenance of AST are modifiable and can inform intervention development.

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A conjuntura atual económica, financeira e social tem pressionado o uso racional dos recursos existentes, seja pelo setor privado ou pelo setor público. Contudo, nem sempre as empresas e organizações conseguem fazê-lo da melhor forma possível, seja por falta de experiência, por falta de conhecimento ou simplesmente pela aversão à mudança. É no contexto de redução de custos/ gastos que a gestão Lean tem vindo a afirmar-se como um método/filosofia eficaz e o suficientemente flexível e robusta para se adaptar a diferentes realidades organizacionais. Nesse seguimento, este relatório testemunha a introdução da gestão Lean numa organização do Terceiro Setor – Centro Social e Paroquial da Vera Cruz, e questiona o seu valor acrescentado mesmo se implementada numa lógica parcelar e numa organização ainda globalmente longe de estar organizada segundo uma lógica Lean. Os resultados obtidos no âmbito do projeto em questão parecem apontar para uma operação bem sucedida e com boas perspetivas futuras, caso a referida organização dê continuidade à sua implementação.

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The main purpose of this PhD thesis was to provide convincing demonstration for a breakthrough concept of pyroelectrolysis at laboratory scale. One attempted to identify fundamental objections and/or the most critical constraints, to propose workable concepts for the overall process and for feasible electrodes, and to establish the main requirements on a clearer basis. The main effort was dedicated to studying suitable anode materials to be developed for large scale industrial units with molten silicate electrolyte. This concept relies on consumable anodes based on iron oxides, and a liquid Fe cathode, separated from the refractory materials by a freeze lining (solid) layer. In addition, one assessed an alternative concept of pyroelectrolysis with electron blocking membranes, and developed a prototype at small laboratory scale. The main composition of the molten electrolyte was based on a magnesium aluminosilicate composition, with minimum liquidus temperature, and with different additions of iron oxide. One studied the dynamics of devitrification of these melts, crystallization of iron oxides or other phases, and Fe2+/Fe3+ redox changes under laser zone melting, at different pulling rates. These studies were intended to provide guidelines for dissolution of raw materials (iron oxides) in the molten electrolyte, to assess compatibility with magnetite based consumable anodes, and to account for thermal gradients or insufficient thermal management in large scale cells. Several laboratory scale prototype cells were used to demonstrate the concept of pyroelectrolysis with electron blocking, and to identify the most critical issues and challenges. Operation with and without electron blocking provided useful information on transport properties of the molten electrolyte (i.e., ionic and electronic conductivities), their expected dependence on anodic and cathodic overpotentials, limitations in faradaic efficiency, and onset of side electrochemical reactions. The concept of consumable anodes was based on magnetite and derived spinel compositions, for their expected redox stability at high temperatures, even under oxidising conditions. Spinel compositions were designed for prospective gains in refractoriness and redox stability in wider ranges of conditions (T, pO2 and anodic overpotentials), without excessive penalty for electrical conductivity, thermomechanical stability or other requirements. Composition changes were also mainly based on components of the molten aluminosilicate melt, to avoid undue contamination and to minimize the dissolution rate of consumable anodes. Additional changes in composition were intended for prospective pyroelectrolysis of Fe alloys, with additions of different elements (Cr, Mn, Ni, Ti).

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INHALT: l. Einleitung und Standortbestimmung 2. Japanische Wertvorstellungen 3. Inhalte der Lean Production 4. Fertigungssegmentierung 5. Informationsmanagement mit CIM- und Logistik-Komponenten 6. Logistikgerechte Strukturen der Lean Production 7. Realisierung der Lean Production 8. Zusammenfassung

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Obwohl durchgängige CIM- und Logistik-Konzepte zur Erfüllung der permanent steigenden Kundenforderungen hinsichtlich spezifischer Produktausführungen bei qualitätsgerechter und termintreuer Auslieferung in den meisten Unternehmen noch nicht realisiert sind, beginnt bereits die Diskussion um eine neue Unternehmensstrategie: die "Lean Production". Das Ziel heißt diesmal, in allen Bereichen Ressourcen zu minimieren, um mit Hilfe einer schlanken Fertigung bei den Kosten Weltstandard zu erreichen.

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Kleine Losgrößen, bedingt durch immer neue Kundenanforderungen nach speziellen Produktausführungen, lassen aus Wettbewerbsgründen eine konventionelle Massenproduktion mit unfelxiblen Produktionsabläufen nicht mehr zu. Neue Wege sind nötig, um gegenüber der Konkurrenz - besonders aus Fernost - auch in Zukunft wettbewerbsfähig zu bleiben. Dabei hat gerade diese Konkurrenz mnachen Anstoss zur Veränderung durch für uns ungewohnte Wettbewerbsstrategien gegeben. Auch wenn viele der Grundlagen und Methoden dieser Strategien aus Europa stammen, wurden sie sehr geschickt und innovativ den dortigen gesellschaftlichen und technologischen Randbedingungen angepasst. Nun sind sie in anderer Form bei uns wieder ins Bewusstsein zurückgekehrt. Dies gilt insbesondere für Lean Production, die "schlanke" Produktion. Hier können die Fachleute bei uns lernen, wie sich durch Mitarbeitermotivierung, Vereinfachung und Dezentralisierung der Abläufe der Weltkostenstand wieder erreichen lässt.

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Relatório de estágio de mestrado, Ciências da Educação (Formação de Adultos), Universidade de Lisboa, Instituto de Educação, 2011

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OBJECTIVE: The colonic microbiota ferment dietary fibres, producing short chain fatty acids. Recent evidence suggests that the short chain fatty acid propionate may play an important role in appetite regulation. We hypothesised that colonic delivery of propionate would increase peptide YY (PYY) and glucagon like peptide-1 (GLP-1) secretion in humans, and reduce energy intake and weight gain in overweight adults. DESIGN: To investigate whether propionate promotes PYY and GLP-1 secretion, a primary cultured human colonic cell model was developed. To deliver propionate specifically to the colon, we developed a novel inulin-propionate ester. An acute randomised, controlled cross-over study was used to assess the effects of this inulin-propionate ester on energy intake and plasma PYY and GLP-1 concentrations. The long-term effects of inulin-propionate ester on weight gain were subsequently assessed in a randomised, controlled 24-week study involving 60 overweight adults. RESULTS: Propionate significantly stimulated the release of PYY and GLP-1 from human colonic cells. Acute ingestion of 10 g inulin-propionate ester significantly increased postprandial plasma PYY and GLP-1 and reduced energy intake. Over 24 weeks, 10 g/day inulin-propionate ester supplementation significantly reduced weight gain, intra-abdominal adipose tissue distribution, intrahepatocellular lipid content and prevented the deterioration in insulin sensitivity observed in the inulin-control group. CONCLUSIONS: These data demonstrate for the first time that increasing colonic propionate prevents weight gain in overweight adult humans.

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The current regulatory framework for maintenance outage scheduling in distribution systems needs revision to face the challenges of future smart grids. In the smart grid context, generation units and the system operator perform new roles with different objectives, and an efficient coordination between them becomes necessary. In this paper, the distribution system operator (DSO) of a microgrid receives the proposals for shortterm (ST) planned outages from the generation and transmission side, and has to decide the final outage plans, which is mandatory for the members to follow. The framework is based on a coordination procedure between the DSO and other market players. This paper undertakes the challenge of optimization problem in a smart grid where the operator faces with uncertainty. The results show the effectiveness and applicability of the proposed regulatory framework in the modified IEEE 34- bus test system.

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Distribution systems are the first volunteers experiencing the benefits of smart grids. The smart grid concept impacts the internal legislation and standards in grid-connected and isolated distribution systems. Demand side management, the main feature of smart grids, acquires clear meaning in low voltage distribution systems. In these networks, various coordination procedures are required between domestic, commercial and industrial consumers, producers and the system operator. Obviously, the technical basis for bidirectional communication is the prerequisite of developing such a coordination procedure. The main coordination is required when the operator tries to dispatch the producers according to their own preferences without neglecting its inherent responsibility. Maintenance decisions are first determined by generating companies, and then the operator has to check and probably modify them for final approval. In this paper the generation scheduling from the viewpoint of a distribution system operator (DSO) is formulated. The traditional task of the DSO is securing network reliability and quality. The effectiveness of the proposed method is assessed by applying it to a 6-bus and 9-bus distribution system.

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A evolução tecnológica, com particular incidência nas tecnologias de informação, e a necessidade de uma integração cada vez mais profunda do sector da manutenção na gestão estratégica global da empresa, contribuíram para o aparecimento dos sistemas de e-maintenance. Por outro lado, os conceitos associados à manutenção deverão estar cada vez mais associados à manutenção remota. Assim, o desenvolvimento de plataformas de e-maintenance, entendidas como a agregação de software e hardware e outras tecnologias integradas, permitiram implementar serviços, que foram determinantes para a evolução deste conceito. Nesta comunicação apresenta-se uma plataforma de e-maintenance aplicada a um sistema automatizado de pesagem de viaturas na indústria cimenteira. O sistema é baseado na monitorização constante da degradação dos componentes críticos que, através de um sistema de alertas, permite antecipar as falhas notificando, atempadamente, a equipe de operadores específicos. A aplicação foi desenvolvida na Framework SLV Cement da empresa Cachapuz. Possuindo vários módulos de gestão da manutenção esta plataforma permite definir e controlar todo o fluxo de informação.

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In the proposed model, the independent system operator (ISO) provides the opportunity for maintenance outage rescheduling of generating units before each short-term (ST) time interval. Long-term (LT) scheduling for 1 or 2 years in advance is essential for the ISO and the generation companies (GENCOs) to decide their LT strategies; however, it is not possible to be exactly followed and requires slight adjustments. The Cournot-Nash equilibrium is used to characterize the decision-making procedure of an individual GENCO for ST intervals considering the effective coordination with LT plans. Random inputs, such as parameters of the demand function of loads, hourly demand during the following ST time interval and the expected generation pattern of the rivals, are included as scenarios in the stochastic mixed integer program defined to model the payoff-maximizing objective of a GENCO. Scenario reduction algorithms are used to deal with the computational burden. Two reliability test systems were chosen to illustrate the effectiveness of the proposed model for the ST decision-making process for future planned outages from the point of view of a GENCO.