979 resultados para Manutenção lean


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There were three principal research aims: primarily, Lean is and always should be regarded as a business model as depicted by Toyota who is dedicated towards finding better ways of producing cars; consequently an investigation of whether organisations embracing Lean as a philosophy were indeed more triumphant. An adapted balanced scorecard was used which embraced strategic, operation and indices focused towards the future prospects of an organisation. Secondly, it was obligatory to explicitly and precisely determine whether an organisation espoused Lean as a philosophy as opposed to another process or strategy. Thirdly, since Lean has to be envisaged as a never-ending journey; it was important to map out the Lean journey and to be able to categorize the juncture an organisation occupies at any particular phase of its overall implementation. This affords an opportunity to advise an organisation of specific requirements it needs to satisfy should it wish to embrace Lean as a philosophy. The methodological approach focused on the effective deployment of survey questionnaires in sixty-eight organisations and seven extensive case studies in manufacturing organisations of varying sizes. The CIMA organisational classification, the Puttick grid and the Product-Process matrix were used to analyse the range of organisations used in this investigation. Whilst there was a requirement to investigate whether Lean indeed equates to success, pertinent performance measurement was considered decisive; the DMP Model (Maltz et al., 2003) was modified to perform this role. An unremitting theme both in literature concerning the implementation of Lean and in the research evolves around the notion of corporate cultures. Its relevance is explored further within the analysis. In accepting the premise that Lean incorporates a journey, it was fundamental to identify the voyage. Prevalent frameworks are deficient in identifying the sustainability and ideological facets of Lean. Consequently, an extensive Lean audit was developed and piloted in twenty disparate organisations.

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Interest is growing around the application of lean techniques to new product introduction (NPI). Although a relatively emergent topic compared with the application of ‘lean’ within the factory, since 2000 there has been an exponential rise in the literature on this subject. However, much of this work focuses on describing and extolling the virtues of the ‘Toyota approach’ to design. Therefore, by way of a stock take for the UK, the present authors' research has set out to understand how well lean product design practices have been adopted by leading manufacturers. This has been achieved by carrying out in-depth case studies with three carefully selected manufacturers of complex engineered products. This paper describes these studies, the detailed results and subsequent findings, and concludes that both the awareness and adoption of practices is generally embryonic and far removed from the theory advocated in the literature.

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Lean manufacturing is now widely accepted amongst UK based manufacturers as a valuable aid to achieving competitiveness. The associated principles, tools and techniques have been well documented since the 1980s and there are many competent practitioners, consultants and academics promoting Lean manufacturing. Therefore, it is useful to ask how well UK manufacturers are progressing along the Lean journey? This paper therefore provides an insight into this question by presenting the results, based on indepth case studies of five representative companies, that reflect progress being made within the UK manufacturing sector.

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Lean is usually associated with the ‘operations’ of a manufacturing enterprise; however, there is a growing awareness that these principles may be transferred readily to other functions and sectors. The application to knowledge-based activities such as engineering design is of particular relevance to UK plc. Hence, the purpose of this study has been to establish the state-of-the-art, in terms of the adoption of Lean in new product development, by carrying out a systematic review of the literature. The authors' findings confirm the view that Lean can be applied beneficially away from the factory; that an understanding and definition of value is key to success; that a set-based (or Toyota methodology) approach to design is favoured together with the strong leadership of a chief engineer; and that the successful implementation requires organization-wide changes to systems, practices, and behaviour. On this basis it is felt that this review paper provides a useful platform for further research in this topic.

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The purpose of this research has been to investigate the extent to which Lean techniques have been applied to indirect or White Collar activities within manufacturing operations. The work has been based on a systematic review of the literature and six UK based case studies. Both are described in the paper. The findings from this work include, for example, that there are few reports off the application of Lean in this context. The more substantive papers focus on NPI and Project Management, where as, Support and ‘Front Office’ activities are covered only briefly in ‘trade journal’ articles. These do demonstrate that Lean techniques can be applied successfully to non-production related activities, and there are significant opportunities for work in this area. However, the definition of Lean is evolving and practitioners do not share a common understanding of terminology. This may undermine their accuracy when reporting the application of Lean techniques.

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The increasing need for maintenance, repair, and overhaul (MRO) organizations to meet customers' demands in quality and reduced lead times is key to its survival within the aviation industry. Furthermore, with the unpredictability in the global market and difficulties with forecasting characteristic of the MRO industry there is an increased need for the reevaluation of the operation models of organizations within this sector. However, severe economic turmoil and ever-increasing global competition introduce the opportunity for the adoption of a resilient, tried, and tested business operation model such as 'Lean'. In order to understand this concept, its long-term viability, and its application within the aerospace MRO sector fully, this paper presents the state-of-the-art in terms of the adoption of Lean within the MRO industry by carrying out a systematic review of the literature. This paper establishes the common perception of Lean by the MRO industry and the measurable progress that has been made on the subject. Some issues and challenges are also highlighted including the misconceptions that arise from the direct transference of the perception of Lean from other industrial sectors into the aerospace MRO industry. The 'enablers and inhibitors' of Lean within the aviation industry are also discussed. This paper exposes the scarcity of the literature and the general lagging behind of the industry to the adoption of the Lean paradigm and thus highlights areas where further research is required. © 2011 Authors.

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In order to study the effect of washcoat composition on lean NOx trap (LNT) aging characteristics, fully formulated monolithic LNT catalysts containing varying amounts of La-stabilized CeO2 (5 wt% La2O3) or CeO2-ZrO2 (Ce:Zr = 70:30) were subjected to accelerated aging on a bench reactor. Subsequent catalyst evaluation revealed that aging resulted in deterioration of the NOx storage, NOx release and NOx reduction functions, whereas the observation of lean phase NO2 slip for all of the aged catalysts indicated that LNT performance was not limited by the kinetics of NO oxidation. After aging, all of the catalysts showed increased selectivity to NH3 in the temperature range 250–450 °C. TEM, H2 chemisorption, XPS and elemental analysis data revealed two main changes which can explain the degradation in LNT performance. First, residual sulfur in the catalysts, present as BaSO4, decreased catalyst NOx storage capacity. Second, sintering of the precious metals in the washcoat was observed, which can be expected to decrease the rate of NOx reduction. Additionally, sintering is hypothesized to result in segregation of the precious metal and Ba phases, resulting in less efficient NOx spillover from Pt to Ba during NOx adsorption, as well as decreased rates of reductant spillover from Pt to Ba and reverse NOx spillover during catalyst regeneration. Spectacular improvement in LNT durability was observed for catalysts containing CeO2 or CeO2-ZrO2 relative to their non-ceria containing analog. This was attributed to (i) the ability of ceria to participate in NOx storage/reduction as a supplement to the main Ba NOx storage component; (ii) the fact that Pt and CeO2(-ZrO2) are not subject to phase segregation; and (iii) the ability of ceria to trap sulfur, resulting in decreased sulfur accumulation on the Ba component.

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Sibutramine is a satiety-inducing serotonin-noradrenaline reuptake inhibitor that acts predominantly via its primary and secondary metabolites. This study investigates the possibility that sibutramine and/or its metabolites could act directly on white adipose tissue to increase lipolysis. Adipocytes were isolated by a collagenase digestion procedure from homozygous lean (+/+) and obese-diabetic ob/ob mice, and from lean nondiabetic human subjects. The lipolytic activity of adipocyte preparations was measured by the determination of glycerol release over a 2-hour incubation period. The primary amine metabolite of sibutramine M2, caused a concentration-dependent stimulation of glycerol release by murine lean and obese adipocytes (maximum increase by 157 ± 22 and 245 ± 1696, respectively, p < 0.05). Neither sibutramine nor its secondary amine metabolite M1 had any effect on lipolytic activity. Preliminary studies indicated that M2-induced lipolysis was mediated via a beta-adrenergic action. The non-selective beta-adrenoceptor antagonist propranolol (10-6M) strongly inhibited M2-stimulated lipolysis in lean and obese murine adipocytes. M2 similarly increased lipolysis by isolated human omental and subcutaneous adipocytes (maximum increase by 194 ± 33 and 136 ± 4%, respectively, p < 0.05) with EC50 values of 12 nM and 3 nM, respectively. These results indicate that the sibutramine metabolite M2 can act directly on murine and human adipose tissue to increase lipolysis via a pathway involving beta-adrenoceptors. © Georg Thieme Verlag KG Stuttgart.

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The application of Lean Six Sigma (LSS) varies in different regions of the world in terms of both level of understanding and acceptability. Employing a qualitative methodological approach, this paper aims to explore factors hindering the acceptability of the LSS initiative in organizations and list factors required for successful application and implementation in a developing economy from the perspective of LSS consultants. Using Nigeria as a case study, primary data were collected though a number of semi-structured interviews with representatives of leading continuous improvement consultancy firms in Nigeria. Finding draws out links between major factors such as drivers and motivation, LSS performance, marketability and challenges to the acceptability and applicability of LSS in Nigeria. Further findings highlight major factors such as lack of management buy-in, level of awareness, certification driven market, Nigerian environment and culture, etc as problems that hinder successful implementation of LSS in Nigeria. This paper contributes to the theoretical foundation of critical success factors required for the implementation of Lean Six Sigma, with results from the experience of a developing economy.