The behavior of repairable equipment is often modeled under assumptions such as perfect repair, minimal repair, or negligible repair. However the majority of equipment behavior does not fall into any of these categories. Rather, repair actions do take time and the condition of equipment following repair is not strictly "as good as new" or "as bad as it was" prior to repair. Non-homogeneous processes that reflect this type of behavior are not studied nearly as much as the minimal repair case, but they far more realistic in many situations. For this reason, the quasi-renewal process provides an appealing alternative to many existing models for describing a non-homogeneous process. A quasi-renewal process is characterized by a parameter that indicates process deterioration or improvement by falling in the interval [0,1) or (1,Infinity) respectively. This parameter is the amount by which subsequent operation or repair intervals are scaled in terms of the immediately previous operation or repair interval. Two equivalent expressions for the point availability of a system with operation intervals and repair intervals that deteriorate according to a quasi-renewal process are constructed. In addition to general expressions for the point availability, several theoretical distributions on the operation and repair intervals are considered and specific forms of the quasi-renewal and point availability functions are developed. The two point availability expressions are used to provide upper and lower bounds on the approximated point availability. Numerical results and general behavior of the point availability and quasi-renewal functions are examined. The framework provided here allows for the description and prediction of the time-dependent behavior of a non-homogeneous process without the assumption of limiting behavior, a specific cost structure, or minimal repair. / Ph. D.

Maintenance of medical equipment plays an important role in ensuring the healthcare quality so that the care can be conducted with minimal risk. Preventive maintenance is performed to maintain the equipment in satisfactory operating condition, while corrective maintenance is made when there is an unpredicted maintenance requirement. This study aims to determine what effect preventive maintenance has on corrective maintenance. A correlation analysis, regression analysis and survival analysis are performed on work-order data from 2000-2021. The results obtained indicate that increasing the number of preventive maintenances made to medical equipment will decrease the number of corrective maintenances required for the medical equipment.

Yes / Wind Energy published by John Wiley & Sons Ltd. Maintenance is essential in keeping wind energy assets operating efficiently. With the development of advanced condition monitoring, diagnostics and prognostics, condition-based maintenance has attracted much attention in the offshore wind industry in recent years. This paper models various maintenance activities and their impacts on the degradation and performance of offshore wind turbine components. An integrated maintenance strategy of corrective maintenance, imperfect time-based preventive maintenance and condition-based maintenance is proposed and compared with other traditional maintenance strategies. A maintenance simulation programme is developed to simulate the degradation and maintenance of offshore wind turbines and estimate their performance. A case study on a 10-MW offshore wind turbine (OWT) is presented to analyse the performance of different maintenance strategies. The simulation results reveal that the proposed strategy not only reduces the total maintenance cost but also improves the energy generation by reducing the total downtime and expected energy not supplied. Furthermore, the proposed maintenance strategy is optimised to find the best degradation threshold and balance the trade-off between the use of condition-based maintenance and other maintenance activities. / UK Engineering and Physical Sciences Research Council (EPSRC). Grant Number: EP/P009743/1

Esta investigación tiene como objetivo general mejorar la productividad al rediseñar el sistema de mantenimiento de una empresa molinera del departamento de Lambayeque Al efectuar el diagnóstico de las operaciones de producción y mantenimiento de la empresa, se evidenció baja productividad siendo la principal causa el deficiente mantenimiento preventivo, se incumplió con el 45 % de este; 207 horas de parada por mantenimiento correctivo dejando de producir 1705 t de arroz valorizados en S/. 1 875 500, además 7% de reprocesos; no se realizan capacitaciones a los trabajadores; falta de orden y limpieza, ausencia de suministros. Ante todo esto se propone rediseñar el sistema de mantenimiento para incrementar los rendimientos de la planta molinera de arroz con herramienta lean de gestión como el mantenimiento productivo total –TPM, sumado a una serie de actividades, capacitaciones a los trabajadores y elaboración de protocolos, procedimientos actualizados de manuales de mantenimiento preventivo, nuevos formatos de gestión TPM, así también se propone control y seguimiento de TPM utilizando indicadores de control como eficiencia global del equipo. Después del rediseño se estima mejorar la productividad total de 1,23 a 1,29; incremento de los rendimientos de materia prima de 58% a 63%. El % de cumplimiento de mantenimiento preventivo aumento de 55% a 62%, se lograría reducir el número de fallas de 41 a 22 por mes y la Eficiencia Global de los equipos aumentaría de 52 a 63%. Obteniendo un beneficio – costo de 3,8 soles. / The general objective of this research is to improve productivity by redesigning the maintenance system of a milling company in the department of Lambayeque. When making the diagnosis of the production and maintenance operations of the company, low productivity was evidenced, the main cause being deficient preventive maintenance, 45% of this was met; 207 hours of stoppage due to corrective maintenance, ceasing to produce 1,705 t of rice valued at S /. 3 751 000, plus 7% of reprocesses; workers are not trained; lack of order and cleanliness, lack of supplies. Given all this, it is proposed to redesign the maintenance system to increase the yields of the rice milling plant with a lean management tool such as total productive maintenance -TPM, added to a series of activities, training of workers and development of protocols, procedures updated preventive maintenance manuals, new TPM management formats, as well as control and monitoring of TPM using control indicators such as overall equipment efficiency. After the redesign, it is estimated to improve total productivity from 1.23 to 1.29; increase in raw material yields from 58% to 64%. The% of preventive maintenance compliance increased from 45% to 62%, the number of failures would be reduced from 41 to 22 per month and the Global Efficiency of the equipment would increase from 52 to 63%. Obtaining a benefit - cost of 3.8 soles.

La investigación tiene como objetivo generar proponer un plan de mantenimiento basado en RCM para disminuir los tiempos de parada en la empresa Multiservicios Astolingón S.A.C., así mismo cuenta con los siguientes objetivos específicos: diagnosticar el estado actual de la maquinaria de la empresa mediante los reportes de fallas; identificar en que índice de criticidad de fallas se encuentra la etapa utilizando el análisis de criticidad, árbol de fallas, análisis de modo y efecto de fallo (AMEF); proponer el plan de gestión de mantenimiento en los equipos con mayor criticidad de la empresa, a partir de los resultados del análisis de criticidad, árbol de fallas, AMEF; y evaluar la reducción tiempo de paradas, comparando los tiempos del mantenimiento correctivo aplicado actualmente en la empresa, con el mantenimiento preventivo basado en RCM. En cuanto a la metodología es de enfoque cualitativo, la técnica utilizada es la indirecta, ya que se usará las herramientas de observación y revisión de reportes (como apoyo una entrevista). / The investigation has how to generate propose a maintenance plan based on RCM to reduce downtime in the company Multiservices Astolingón S.A.C., likewise has the following specific objectives: detect the current state of the company's machinery through failure reports; identify in which failure criticality index the stage is located using the criticality analysis, fault tree, failure mode and effect analysis (FMEA); proposes the maintenance management plan for the most critical equipment in the company, based on the results of the criticality analysis, fault tree, AMEF; and evaluate the reduction of downtime, comparing the times of corrective maintenance currently applied in the company, with preventive maintenance based on RCM. As for the methodology, it is of a qualitative approach, the technique used is indirect, since the tools of observation and review of reports will be used (as support for an interview).

Följande studie har utförts på begäran av energiföretaget Norrenergi AB, där det finns en önskan att tillförlitlighetssäkra den nuvarande driften av stofttransportsystemet tillhörande två av värmeverkets hetvattenpannor. Studien har undersökt huruvida det finns möjlighet att framförallt minska underhållskostnaderna. Studien har framförallt inriktats mot två stofttransportfläktar som vardera tillhör ett stofttransportsystem, eftersom mycket underhållsarbete lagts på de fläktarna. En jämförelse med andra liknande verk har även utförts då det visats att Norrenergi AB:s lösning av stofttransporten är ytterst ovanlig. Vidare har en analys av fläktarna utförts, vilken visade att de är underdimensionerade för systemet. Det har konstaterats utifrån genomförda SPM-, temperatur- och bullermätningar. Olika typer av lösningar på problemet har undersökts och då på en förändring av hela systemet, alternativt enbart av fläktarna eller lagren till stofttransportfläktarna. Rapporten har utmynnat i flera förslag vilka innefattar en ny systemutformning, installation av nya fläktar samt en uppgradering av det nuvarande systemet, där installation av nya fläktar rekommenderas. / This study has been carried out at the request by the energy company Norrenergi AB. It consists of an analysis on how they can reduce the maintenance regarding two dust transporting fans installed in the flue gas cleaning compartment of their thermal power plant. The study also compares what solutions other plants have regarding the dust-transport. The solution installed at Norrenergi AB was found to be rather unusual. Measurements and calculations have been performed to investigate further what have caused the high maintenance on the fans. The study looks into what upgrades are available to the entire dust transporting system. The result of the study turned into different suggestions, which includes a new configuration of the dust transporting system, and installation of new fans and also an upgrade of the existing dust transporting system. Among the suggestions the final recommendation is the alternative of installing new fans.

The main purpose of this research is to present a solution that enable to manage efficient and reliable way, all of the information in relation to control, tracking and the hospital equipment maintenance. So, was taken as an object of study of Engineering Department of the Central Hospital of the Air Force of Peru, which presents a lot of administrative deficiencies character in its internal processes of reception, record and closing of Work Orders as well as the preventive and corrective maintenance of the hospital equipment of the HCFAP.The contemplated solution comprises from analysis and design to the development of some use cases more significant of the application. / El presente trabajo de investigación tiene como propósito fundamental presentar una solución que permita administrar de forma eficiente y confiable toda la información respecto al control, seguimiento y mantenimiento del equipamiento hospitalario. Para ello se tomó como objeto de estudio al Departamento de Ingeniería del Hospital Central de la Fuerza Aérea del Perú, el cual presenta muchas deficiencias de carácter administrativo en sus procesos internos de recepción, registro y cierre de Órdenes de Trabajo así como el mantenimiento preventivo y correctivo de los equipos hospitalarios del HCFAP. La solución contemplada abarca desde el análisis y diseño hasta el desarrollo de algunos casos de uso más significativos de la aplicación.

O problema de programação de operações em ambiente no-wait flow shop tem sido abordado desde a década de 60. Por se tratar de um ambiente em que as tarefas devem ser processadas continuamente e sem interrupções entre uma máquina e outra, um tempo de espera entre o início da tarefa anterior e o início da tarefa atual deve ser determinado na primeira máquina. Neste sentido, uma vez que a tarefa inicia seu processamento, as máquinas devem estar disponíveis para que atendam a restrição de no-wait. Portanto, operações de manutenção preventiva são necessárias para que a programação seja atendida sem maiores problemas. Este trabalho aborda dois problemas: no-wait flow shop e no-wait flow shop com operações de manutenção preventiva. O critério de desempenho adotado foi a duração total da programação (makespan). Por meio de uma revisão de literatura, mecanismos de construção de soluções foram identificadas e classificadas e, baseando-se em tais, novos métodos heurísticos construtivos simples e compostos foram propostos para o problema no-wait flow shop e uma heurística composta foi desenvolvida considerando as operações de manutenção preventiva. Experimentações computacionais para os dois problemas foram realizadas para fins de comparação e avaliação dos métodos propostos com os métodos heurísticos construtivos da literatura. Para o problema Fm|no - wait|Cmax resultados evidenciaram que as heurísticas propostas H4GPSLLS e MH4GPSLLS superaram as heurísticas da literatura em qualidade de solução, com diferença estatisticamente significativa no nível de 5% de significância. Para o problema Fm|no - wait, m(k)|Cmax, pode-se constatar que a heurística BIHLS e as heurísticas H4GPSLLS e MH4GPSLLS apresentaram desempenho superior com diferença estatística significativa no nível de 5% de significância em comparação as heurísticas da literatura. / The no-wait flow shop scheduling problem has been studied since 60\'s. In this environment, jobs must be processed continuously without interruption between one machine and another, and because of this, a delay between the start time of the previous job and the start time of the current job must be determined in the first machine. In this sense, since a job starts its processing, the machines must be available to respect the no-wait constraint. Therefore, preventive maintenance operations are needed. This work adresses two problems: the m machine no-wait flow shop and the m machine no-wait flow shop with preventive maintenance operations. The performance measure adopted was the makespan. By means of a literature review, mechanisms of solution construction were identified and classified. New simple and composite constructive heuristics were proposed to the no-wait flow shop problem and a new composite constructive heuristic was developed considering the preventive maintenance operations. Computational experiments and their respective analyses for both problems were carried out to compare and evaluate the performance between the proposed methods and the constructive heuristics of the literature. Regarding Fm|no - wait|Cmax problem, results show that the proposed heuristics H4GPSLLS and MH4GPSLLS outperformed the heuristics of the literature in quality of the solution and is statistically significative to 5% of significance level. To the Fm|no - wait, m(k)|Cmax problem it can be seen that the proposed heuristic BIHLS and H4GPSLLS and MH4GPSLLS outperformed the heuristics of the literature and is statistically better to 5% of significance level.

O impacto do Homem sobre a Terra, desde a extração intensiva dos recursos da natureza, extinção das espécies, emissões para o ar e água, consumo de energia e água até as mudanças climáticas do planeta, exigem medidas de contenção e preservação do meio ambiente. O futuro da humanidade é questionado e algo deve ser feito. Nesse contexto surge o conceito de desenvolvimento sustentável. Responsável pelo consumo de 40 a 50% da matéria-prima mundial, 12% da água e 40% das emissões de gases de efeito estufa, a indústria da construção possui importante papel na mitigação dos efeitos nocivos para o meio ambiente e capacidade de atingir altos índices de sustentabilidade. Dentro do ciclo de vida de uma edificação, a fase de Operação/Uso provoca grandes consequências ao meio ambiente e oferece grandes oportunidades de redução dos efeitos adversos. Nessa fase as atividades de manutenção predial acabam por ter seu valor reconhecido. As diversas estratégias de manutenção, em especial a manutenção preventiva baseada em condição, colaboram efetivamente para a durabilidade, desempenho e função da edificação e seus sistemas prediais. Procedimentos de manutenção estão associados à baixa qualidade do ar. A manutenção de sistemas de ar condicionado tem especial destaque devido às consequências para a saúde, bem-estar e produtividade dos ocupantes do edifício. / Due to extensive extraction of natures resources, extinction of species, emission of gases into the atmosphere, water and power consumption, to climatic changes of the planet, mankinds impact on earth requires containment and preservation of the environment. The future of humanity is being questioned and something must be done. Responsible for the consumption of 40 to 50% of raw materials worldwide, 12% of water and 40% of emissions of gases into the atmosphere causing the greenhouse effect, the construction industry has an important role in alleviating the adverse impacts on the environment and the ability to achieve high sustainable levels. Within the lifecycle of a building, the phase of operation/use causes significant environmental consequences but also offers opportunities to alleviate adverse effects. In this phase, the value of building maintenance activities has been recognized. The various strategies for maintenance, principally preventive condition- based maintenance should collaborate effectively towards the durability, performance, function and systems of a building. Air-conditioning maintenance procedures are associated with poor air quality. The maintenance of air-conditioning systems has a special significance due to the effects on health, well-being and productivity of the occupants of the building.

O objetivo da pesquisa é compreender as práticas culturais ligadas aos processos de concentração e desconcentração cartorária e dos autos judiciais cafeeiros da região do Fundo do Vale do Paraíba Paulista. O estudo é focado nas Varas de Comarcas de Bananal, Cruzeiro, Lorena, São José do Barreiro e Silveiras, das quais a documentação em análise é originária. Após passar pelo recolhimento dos processos que corriam riscos de eliminação por decisão judicial, a documentação está presentemente custodiada no Museu Major Novaes em Cruzeiro, São Paulo. A pesquisa examina os aspectos de conservação material desse patrimônio cultural documental, tendo em vista as várias ações de reconhecimento e proteção empreendidas desde a década de 1970. Paralelamente, a dissertação aborda questões patrimoniais de ordem imaterial, identificadas por meio das análises das diretrizes, práxis institucionais, bem como por intermédio das histórias das pessoas que tiveram contato com o acervo. O estudo discute ainda a evolução da produção acadêmica vinculada a este patrimônio, evidenciando sua importância como base documental para a revisão de perspectivas históricas que contribuiram para leituras mais amplas sobre a sociedade do período do café. Considerando a relevância da produção acadêmica na valorização destes documentos, a pesquisa evidencia a necessidade da criação de políticas integradas de preservação dos mesmos. / The goal of this research is to understand the cultural practices at play in the concentration and scattering of the cartorial and judicial documentation of the municipalities of São Paulo State Paraíba River Valley. The study is focused on the cities of Bananal, Cruzeiro, Lorena, São José do Barreiro and Silveiras, from which all the documentation originates. After being collected from sets of processes that were to be eliminated by judicial order, the documentation is currently under the custodianship of the Major Novaes Museum in Cruzeiro, São Paulo. Considering the various assessment and preventive measures taken since the 1970s, the research examines the various aspects pertaining to the conservation conditions of this cultural heritage documentation. Immaterial heritage issues are also taken into account in the discussion, framing such considerations under the light of the directives and common institutional practices, as well as the stories produced by the people that have had contact with the document collection. The dissertation also discusses the evolution of the academic production that has developed itself from research based on this documental legacy, thus bringing to light its importance as a scientific source for the revision of historical perspectives and its contributions for a wider understanding of society during the coffee production cycle. Taking into account its growing significance for relevant academic production, the research highlights the need to implement integrated preservation policies for this documental collection