Reuse of components as opposed to material recovery, recycling or disposal has been identified as one of the most efficient EOL strategies for products. The concept behind reuse is that some components and subassemblies have a design life that exceeds the life of the product itself. In order for reuse to be successfully implemented as an EOL strategy, a designer needs to incorporate into a product a philosophy of Design for Reuse (DfRe) at the early design stage. Reliable methods to assess the remaining life of used components based on a products usage life are also required. Furthermore, current industry practices and literature advocate that there is no methodology to decide which parameters need to be redesigned so as to change the life of a selected component to a desired level. The objective of this research is to develop a methodology to assess the reuse potential of product groups based on component failure mechanisms and their associated critical lifetime prediction design parameters. Utilising these clustered groups mathematical models were then developed to establish the useful life of the components for each clustered group. Finally, a means of equating useful life to design life was established and the relationship between, the failure mechanisms, critical lifetime prediction design parameters and design life were represented in graphical format. In order to achieve the proposed objective, Cluster analysis, in particular Group Technology (GT) and Hierarchical clustering were employed to group components with similar failure mechanisms. Following this, multiple linear regression was used to establish mathematical models based on condition monitoring data for each of the clustered groups and their related critical lifetime prediction design parameters. A sensitivity analysis was conducted using the mathematical models, in order to produce graphical relations between the useful life and design parameters of a product. The validity of the suggested methodology was tested on electric motors and a gearbox as both these components have demonstrated great reuse potential. The results demonstrate that the methodology can assist designers in estimating the design life and associated design parameters with great accuracy, and subsequently aiding in a stratagem for reuse.

Orientador: Fernando Augusto da Silva Marins / Banca: Jorge Muniz Junior / Banca: Michel Carmem Neyra Belderrain / Resumo: Esta dissertação abordou o problema de disponibilidade de peças de reposição para o atendimento às solicitações dos clientes na pós-venda, principalmente dos setores naval, aéreo e siderúrgico, que participam de um mercado que apresenta características próprias. A falta de determinadas peças de reposição acarreta descontentamento ou, pior, a impossibilidade de utilização do produto. Comumente, o planejamento de estoque não leva em consideração a visão da área de suporte ao cliente, que vivencia os conflitos e efeitos causados por eventuais faltas de peças. Dessa forma, este estudo objetivou propor um modelo que auxilie na decisão gerencial, com respeito ao perfil do estoque de peça de reposição na organização. O estudo partiu do pressuposto de que não é viável estocar todos os tipos de peças de reposição, tendo assim que identificar quais agregam valor. Isso foi feito por meio, de um modelo inclusivo, que combinou o Método de Auxílio à Decisão por Múltiplos Critérios e a Combinação desses critérios. O primeiro, através dos julgamentos de diferentes profissionais, objetivou alcançar um resultado consolidado e priorizado, enquanto que o segundo, através da classificação por combinação sem repetição, buscou encontrar grupos com característica semelhantes priorizados entre si. O modelo conseguiu reduzir a dificuldade de seleção de peças de reposição equilibrando as necessidades das diferentes áreas. / Abstract: This study tackled the problem of spare parts availability for the fulfillment of the after-market customers, mainly the naval, aviation and the steel industries, which are part of a market that has its own characteristics. The lack of certain spare parts causes unpleasant situations for customers or, even worse, the impossibility of utilization of product. Normally, the stock planning does not take into consideration the customer support area experience, which goes through the conflicts and effects caused by eventual lack of parts. Thus, this study envisaged to propose a model which can help in management decisions, regarding the profile of spare part stock in the organization. The study considered that it is not viable to stock all kinds of spare parts, thus having to identify which ones can aggregate value for customer. This was done through an inclusive model, matched the Multiple Criteria Decision Aid and the combination of these criterias. The first, envisaged to reach a consolidated and prioritized result, through the judgment of different professionals, whereas the second, sought to find groups with similar characteristics prioritized among each other, through the classification by combination without repetition. The model got to reduce the difficulties of choosing spare parts balancing the needs of different areas. / Mestre

Made available in DSpace on 2014-06-11T19:30:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-05-15Bitstream added on 2014-06-13T19:39:25Z : No. of bitstreams: 1 vieira_ha_me_guara.pdf: 406242 bytes, checksum: 5fb852de1f30a52599d87ed826634d4d (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Esta dissertação abordou o problema de disponibilidade de peças de reposição para o atendimento às solicitações dos clientes na pós-venda, principalmente dos setores naval, aéreo e siderúrgico, que participam de um mercado que apresenta características próprias. A falta de determinadas peças de reposição acarreta descontentamento ou, pior, a impossibilidade de utilização do produto. Comumente, o planejamento de estoque não leva em consideração a visão da área de suporte ao cliente, que vivencia os conflitos e efeitos causados por eventuais faltas de peças. Dessa forma, este estudo objetivou propor um modelo que auxilie na decisão gerencial, com respeito ao perfil do estoque de peça de reposição na organização. O estudo partiu do pressuposto de que não é viável estocar todos os tipos de peças de reposição, tendo assim que identificar quais agregam valor. Isso foi feito por meio, de um modelo inclusivo, que combinou o Método de Auxílio à Decisão por Múltiplos Critérios e a Combinação desses critérios. O primeiro, através dos julgamentos de diferentes profissionais, objetivou alcançar um resultado consolidado e priorizado, enquanto que o segundo, através da classificação por combinação sem repetição, buscou encontrar grupos com característica semelhantes priorizados entre si. O modelo conseguiu reduzir a dificuldade de seleção de peças de reposição equilibrando as necessidades das diferentes áreas. / This study tackled the problem of spare parts availability for the fulfillment of the after-market customers, mainly the naval, aviation and the steel industries, which are part of a market that has its own characteristics. The lack of certain spare parts causes unpleasant situations for customers or, even worse, the impossibility of utilization of product. Normally, the stock planning does not take into consideration the customer support area experience, which goes through the conflicts and effects caused by eventual lack of parts. Thus, this study envisaged to propose a model which can help in management decisions, regarding the profile of spare part stock in the organization. The study considered that it is not viable to stock all kinds of spare parts, thus having to identify which ones can aggregate value for customer. This was done through an inclusive model, matched the Multiple Criteria Decision Aid and the combination of these criterias. The first, envisaged to reach a consolidated and prioritized result, through the judgment of different professionals, whereas the second, sought to find groups with similar characteristics prioritized among each other, through the classification by combination without repetition. The model got to reduce the difficulties of choosing spare parts balancing the needs of different areas.

Most problems in engineering and natural sciences involve parametric equations in which the parameters are not known exactly due to measurement errors, lack of measurement data, or even intrinsic variability. In such problems, one objective is to compute point or aggregate values, called “quantities of interest”. A rapidly growing research area that tries to tackle this problem is Uncertainty Quantification (UQ). As the name suggests, UQ aims to accurately quantify the uncertainty in quantities of interest. To that end, the approach followed in this thesis is to describe the parameters using probabilistic measures and then to employ probability theory to approximate the probabilistic information of the quantities of interest. In this approach, the parametric equations must be accurately solved for multiple values of the parameters to explore the dependence of the quantities of interest on these parameters, using various so-called “sampling methods”. In almost all cases, the parametric equations cannot be solved exactly and suitable numerical discretization methods are required. The high computational complexity of these numerical methods coupled with the fact that the parametric equations must be solved for multiple values of the parameters make UQ problems computationally intensive, particularly when the dimensionality of the underlying problem and/or the parameter space is high. This thesis is concerned with optimizing existing sampling methods and developing new ones. Starting with the Multilevel Monte Carlo (MLMC) estimator, we first prove its normality using the Lindeberg-Feller CLT theorem. We then design the Continuation Multilevel Monte Carlo (CMLMC) algorithm that efficiently approximates the parameters required to run MLMC. We also optimize the hierarchies of one-dimensional discretization parameters that are used in MLMC and analyze the tolerance splitting parameter between the statistical error and the bias constraints. An important contribution of this thesis is the novel Multi-index Monte Carlo (MIMC) method which is an extension of MLMC in high dimensional problems with significant computational savings. Under reasonable assumptions on the weak and variance convergence, which are related to the mixed regularity of the underlying problem and the discretization method, the order of the computational complexity of MIMC is, at worst up to a logarithmic factor, independent of the dimensionality of the underlying parametric equation. We also apply the same multi-index methodology to another sampling method, namely the Stochastic Collocation method. Hence, the novel Multi-index Stochastic Collocation method is proposed and is shown to be more efficient in problems with sufficient mixed regularity than our novel MIMC method and other standard methods. Finally, MIMC is applied to approximate quantities of interest of stochastic particle systems in the mean-field when the number of particles tends to infinity. To approximate these quantities of interest up to an error tolerance, TOL, MIMC has a computational complexity of O(TOL-2log(TOL)2). This complexity is achieved by building a hierarchy based on two discretization parameters: the number of time steps in an Milstein scheme and the number of particles in the particle system. Moreover, we use a partitioning estimator to increase the correlation between two stochastic particle systems with different sizes. In comparison, the optimal computational complexity of MLMC in this case is O(TOL-3) and the computational complexity of Monte Carlo is O(TOL-4).

El presente trabajo de investigación desenvuelve una propuesta de comercialización de repuestos alternativos para maquinaria de construcción con características diferenciadas en términos de diseño y fabricación del producto dentro del segmento del mercado alternativo; brindando piezas mecánicas de encaje perfecto para maquinaria, esto se traduce sustancialmente en la mejora del rendimiento de la maquinaria. En el ambiente de las medianas y pequeñas constructoras, los repuestos alternativos son requeridos cuando el equipo mecánico ha llegado a alcanzar las horas de trabajo dentro de la garantía original; y a partir de este punto en el tiempo de vida de la maquinaria se comienzan a analizar “eficiencia en costos”, originándose la posibilidad del uso del alternativo frente al original y para ello cobra importancia, accesibilidad, la inmediatez, la disponibilidad y precio del repuesto. El segmento de clientes objetivo se caracteriza por dueños de equipo de construcción del líder mundial en maquinaria pesada que operan en proyectos de pequeña o mediana envergadura, quienes hoy se encuentran tomando decisiones a corto plazo sobre la manera de cómo mantener sus equipos, ellos no buscan una reconstrucción completa de sus equipos con partes premium, ellos encuentran mayor valor en la prontitud de arreglar el equipo para volver a trabajar, estas decisiones a menudo están íntimamente relacionadas con presiones internas para atender el flujo de caja y metas mensuales de su negocio. Este segmento de clientes adquiere actualmente repuestos alternativos experimentando insatisfacción por la baja calidad de los productos existentes en el mercado peruano. Para este segmento, la propuesta ofrece el mayor rendimiento que se puede brindar al “Equipo Clásico” empleando piezas de encaje perfecto de gran fiabilidad y confiabilidad con una disponibilidad garantizada a través de una red de distribuidores que serán ubicados a nivel nacional y todo a un costo razonable por los repuestos alternativos. El mercado potencial está compuesto por todos los clientes que poseen equipos de la marca líder en maquinaria pesada clásico (antigüedad mayor a 10 años), que para un parque más de 1,500 equipos representan un potencial de mercado estimado mayor a 7 MM USD; de otro lado el mercado meta está compuesto por el 30% de los clientes del mercado potencial que se alcanzará el 3er año con una oportunidad estimada mayor a los 2MM USD. Los proveedores que operan en el mercado actual de partes y repuestos alternativos se encuentran atomizados y dispersos, en este contexto no existe una marca líder del segmento; esto representa una clara oportunidad para la compañía líder nacional en maquinaria pesada puesto que además del producto ofrecido, puede usar el respaldo que lo caracteriza para conseguir penetrar y posicionarse en el segmento a través del lanzamiento de repuestos ALOR. La inversión para puesta en marcha del negocio es de 800,000 USD, siendo que el financiamiento en deuda corresponde al 62.5%, el destino de las inversiones será en activo tangible relacionadas principalmente con la locación y preparación de las tiendas en los principales conglomerados de repuestos del país y el nivel de stock inicial. Se ha logrado demostrar que el negocio es rentable analizando sus principales indicadores y ello conlleva a que es perfectamente factible continuar con el proceso de expansión del negocio abriendo nuevos puntos de venta en el país; sin embargo; este análisis no forma parte del alcance del desarrollo del presente trabajo de investigación. Es así que para un escenario moderado de proyecciones del flujo de caja del negocio que considera una inflación del 2.5% y un crecimiento del 20% anual de las ventas; tenemos un periodo de retorno de la inversión de 5 años. En la evaluación financiera realizada, obtenemos un Valor Actual Neto de $ 576,184.00, además de una Taza Interna de Retorno del 18% que sobrepasa la tasa de descuento utilizad; lo que nos demuestra que el emprendimiento resulta rentable al superar los ingresos a sus egresos durante los siguientes 5 años futuros. / This research paper develops a proposal for the commercialization of alternative spare parts for heavy construction machinery with the characteristics of differentiation in terms of product design and manufacturing within the segment of the alternative market; providing perfect fit mechanical parts for machinery, this translates substantially into improving the performance of the machinery. In medium and small construction companies, alternative spare parts are required when machinery has reached the working hours within the original warranty; and from this point in the lifetime of the machinery medium and small construction companies begin to analyze "cost efficiency", leading the possibility of using the alternative spare parts against the genuine and for this it becomes important, accessibility, immediacy, availability and price of spare parts. The target customer segment is characterized by construction machinery owners of the world leader in heavy machinery operating on small or medium-sized projects, who are today making short-term decisions on how to keep their machinery, they don't seek a complete overhaul of their machinery with premium parts, they find greater value in the promptness of fixing the machinery to get back to work, these decisions are often closely related to pressures to meet cash flow and monthly business goals. This segment of customers currently acquires alternative spare parts experiencing dissatisfaction with the low quality of existing products in the Peruvian market. For this segment, the proposal offers the highest performance that can be provided to the "Classic Machinery" using perfect fit spare parts of great reliability with guaranteed availability through a network of distributors that will be located nationwide and all of this at a reasonable cost for alternative spare parts. The potential market is made up of all customers who own machinery from the leading brand in classic heavy machinery (older than 10 years), which for a park of more than1,500 equipment represents an estimated market potential greater than USD 7 MM; on the other hand the target market is made up of 30% of the potential market customers who will reach the 3rd year with an estimated opportunity greater than 2MM USD. The suppliers that operate in the current market of alternative spare parts are atomized and dispersed, in this context there is no leading brand in the segment; this represents a good opportunity for the national leader in heavy machinery company since in addition of the product offered, it can use the support that characterizes it to get penetrated and positions in the segment through the launch of ALOR spare parts. The investment for start-up of the business is 800,000 USD, with debt financing being 62.5%, the destination of the investments will be tangible assets related mainly to the location and preparation of the stores in the main conglomerates of country spare parts and initial stock level. It has been possible to demonstrate that the business is profitable by analyzing its main indicators and this means that it is perfectly feasible to continue the process of expanding the business by opening new points of sale in the country; however; this analysis is not part of the scope of the development of this research paper. Thus, for a moderate scenario of business cash flow projections that considers inflation of 2.5% and 20% annual sales growth; we have a 5-year return on investment period. In the financial evaluation, we obtain a Net Present Value of $576,184.00, which shows us that entrepreneurship is profitable by surpassing the income to its egress for the next 5 years. In addition, an Internal Rate of Return of 18% that exceeds the discount rate used. / Trabajo de investigación

I denna studie undersöks ungdomars uppfattningar och tankar om engelska utanför skolan. Nu för tiden kommer ungdomar i kontakt med engelska överallt och engelska har blivit mer av ett andraspråk än ett främmande språk i dagens samhälle. Syftet med studien är att få en djupare förståelse i vad ungdomar tänker om den engelska som de möter på sin fritid. Fyra niondeklassare har intervjuats och de har svarat på frågor om var de möter engelska på sin fritid, hur de använder språket och hur de lär sig engelska utanför skolan. Deras svar visar att ungdomar kommer i kontakt med engelska genom olika källor, de använder språket beroende på deras intressen och de lär sig engelska på olika sätt utanför skolan. / This study investigates adolescents’ perceptions and thoughts on English outside of school. Adolescents come in contact with English everywhere these days and English has become more of a second language than a foreign language in today’s society. The purpose of this study is to get a deeper understanding of what young people think about the English they meet in their spare time. Four young people who are all ninth-graders were interviewed for the study. They were asked questions about where they meet English in their spare time, how they use the language and how they learn English outside of school. Their responses show that adolescents come in contact with English through different sources, they use the language according to their interests and they all go about learning English in different ways.

The  purpose of this work  is to investigate the  extent to which small and medium-sized manufacturing  companies handle spare  parts with  the help of outsourcing,  what factors influence  the decision, and what effect it has on the  maintenance  in  general.   The  aim  of the  study  is to identify  any  challenges that outsourcing  of spare  parts management creates. The  goal of the  study  is to  answer the  two  following  research questions:   ⦁  What are  the driving  forces for outsourcing  spare  parts management?   ⦁  How is maintenance  at  large  is  affected by  outsourcing  of spare  parts management?   It is important to note that due to the unpredictable  demand and uncertainty  about spare  parts, stock planning  and demand forecasts  are  challenges  for  spare  parts managers. This is a problem that can be  solved with the  right outsourcing  strategy.  It is a challenge  for  companies to find the  right solution based on  their manufacturing  and time-to-failure  rate. The  study  is conducted with semi-structured interviews with  people who are  directly connected to spare  parts  management and maintenance. Three  different companies,  about  the same size  on local level  have  been taken in the  study. The  study  has found  that there  is a significant  connection to  how outsourcing  affects  maintenance  and which  factors must be considered.  There  is clear potential for  increased  profitability  through  outsourcing  spare  parts management. The  results of the  study  cannot be  generalized but  must  be  applied  based on  the conditions the company  has.  Currently,  more  and more  companies choose to outsource  the  spare  parts management. This question  needs  to be studied deeply  in every  segment to display  what advantages  and disadvantages this option can have  for  specific  enterprises on different levels

No description available.

This study identifies the concepts of reliability, cost of downtime, cost of spare parts, and procurement lead time as the four key moderators of spare parts availability. These concepts are used to establish a model to manage spare parts inventories. Reliability was assessed in terms of developing failure predictions for major component categories. Cost of downtime was evaluated by identifying various methods for determining costs associated with downtime. Cost of spare parts was examined to find correlations with economic indicators. These correlations were used to predict future price movements. Yearly changes in lead time were identified and correlated with economic indexes to develop movement predictability.

Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Effective management of spare parts inventory is essential to companies because it influences inventory costs and asset utilization. The vast and diverse portfolio of spare parts, intermittent demand patterns and contradicting objectives between departments are examples of some of the factors that complicate Spare Parts Management (SPM). Managers of spare parts are faced with trade-off decisions between risk and cost on a daily basis. These decisions include, amongst many, determining appropriate stock levels and order frequencies. Despite the importance of SPM, decisions are however often made intuitively in practice with little factual support, and the decision-making process is commonly constrained within departmental silos. Even though there is a large body of academic knowledge on this topic, practical applications of spare parts inventory solutions lag behind theoretical studies. The majority of studies in literature focus on single components of SPM, such as demand forecasting and parts classification, whereas fewer studies consider the decision-making process itself. This study proposes a decision-making framework for spare parts inventory management. The framework is based on a wide-ranging literature review that focuses on capturing the essence of Spare Parts Management (SPM), but also acknowledges the interconnectedness of the problem. Therefore, core inventory management principles, as well as closely related topics such as Supply Chain Management (SCM) and Physical Asset Management (PAM), are studied in the context of spare parts. The broad scope of the literature study leads to a holistic approach to the problem and prevents sub-optimization. The proposed framework condenses principles from various fields of study (SCM, PAM, Classification and Inventory Management) into a stepwise methodology presented as a decision-making framework. The objective of the framework is to provide managers with a structured process, based on factual information, to enable better decision-making in the field. Furthermore, the framework aims to capture the fundamentals of SPM in a simplistic manner to ease the adoption of the framework in practice. A case study is conducted in the South African mining industry to validate the framework. The case study demonstrates that the framework is practical, provides structured guidance, and assists managers to make trade-off decisions in managing spare parts inventory. / AFRIKAANSE OPSOMMING: Effektiewe voorraadbestuur van onderdele is belangrik vir maatskappye omdat dit voorraadkoste en die benutting van bates beïnvloed. Die bestuur van onderdele is ’n komplekse probleem. Ondermeer is die portefeulje van onderdele items breed en divers, die vraagpatrone sporadies en word die voorraadvlakke geaffekteer deur kontrasterende doelwitte tussen verskillende departemente. Bestuurders van onderdele word daagliks gekonfronteer met besluite rakende risiko’s en kostes, soos om toepaslike voorraadvlakke te bepaal en om te besluit wanneer om bestellings te plaas. Hierdie besluite word dikwels intuïtief geneem met min feitelike ondersteuning en insette in die besluitnemingsproses word gereeld beperk tot sekere departemente. Ten spyte van die geweldige akademiese belang in die onderwerp, is daar min suksesvolle praktiese toepassings. Die meerderheid van studies in die literatuur fokus op spesifieke elemente van onderdele bestuur, soos vooruitskatting en klassifisering van parte, terwyl minder op die besluitnemingsproses konsentreer. Hierdie studie stel ’n besluitnemingsraamwerk vir die bestuur van onderdele voorraad voor. Die raamwerk is gegrond op ’n deeglike literatuurstudie wat die essensie van onderdele bestuur ondersoek, maar ook die interverbondenheid van die probleem in ag neem. Voorraadbestuurbeginsels en verwante onderwerpe soos Voorsieningskettingbestuur en Fisiese Batebestuur word dus bespreek. Die breë omvang van die literatuurstudie lei tot ’n holistiese benadering wat sub-optimering van die probleem voorkom. Die voorgestelde raamwerk som beginsels uit verskillende relevante studievelde op in ’n stapsgewyse metode wat voorgestel word as ’n besluitnemingsraamwerk. Die doel van die raamwerk is om bestuurders te voorsien met ’n gestruktureerde proses, gebaseer op feitelike inligting, om besluitneming in die veld te verbeter. Verder poog die raamwerk om die fundamentele konsepte in voorraadbestuur vas te vang in ’n eenvoudige manier sodat die raamwerk maklik geïmplementeer kan word in die praktyk. Die voorgestelde raamwerk is gevalideer deur middel van ’n gevallestudie in die Suid-Afrikaanse mynbedryf. Die gevallestudie toon dat die voorgestelde raamwerk prakties is, die besluitnemingsproses op ’n gestruktureerde wyse lei, en bestuurders help om beter, ingeligte besluite te neem.