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1
Gatang'i, Peter Gatheru. "Effective management of machinery in government-operated hospitals". Thesis, Nelson Mandela Metropolitan University, 2010. http://hdl.handle.net/10948/1237.
Testo completoAbstract (sommario):
The methodology and the processes that are followed in the maintenance of government-operated district hospitals in the Eastern Cape Province of South Africa are outlined while the strategies that are employed to roll-out the maintenance plan have been investigated. The challenges in managing hospital maintenance are identified so that it can be improved and advice be given on the strategies currently being used. The objectives of the research were to determine the effectiveness of machinery maintenance in government-operated district hospitals. The study has been carried out by investigating 50 district hospitals within the Eastern Cape Province, with the aim of obtaining knowledge of practices in relation to the strategic plans and best practices in the maintenance industry. The following factors identified by the maintenance staff were found to be most important in maintenance management practices; realistic budgets, adherence to occupational health and safety regulations, engagement of qualified and skilled maintenance staff, good record management in relation to the equipment under maintenance, availability of tools and materials and keeping abreast with the latest technologies and trends of machinery advancement. The study also revealed that the majority of the hospitals use a combination of in-house and outsourced personnel during maintenance, the outsourced part being under contract from the National Department of Public Works Repair and Maintenance Plan (RAMP) projects. Service kits and recommended replacement parts for machinery are rarely stocked on the hospital premises while only minor spare parts that include replacement bulbs, electrical fittings, plumbing fittings and paint are readily available. In addition, the maintenance staff members have little or no input in maintenance budgeting, this aspect is controlled by hospital management. For maintenance to be effective, strategic planning that takes into account carefully thought-out maintenance management systems is the first step in the direction of setting out definite tangible objectives and goals. The real challenge lies in the implementation and sustainability of the maintenance management system and the monitoring thereof.
2
El, Hayek Mustapha Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "Optimizing life-cycle maintenance cost of complex machinery using advanced statistical techniques and simulation". Awarded by:University of New South Wales. School of Mechanical and Manufacturing Engineering, 2006. http://handle.unsw.edu.au/1959.4/24955.
Testo completoAbstract (sommario):
Maintenance is constantly challenged with increasing productivity by maximizing up-time and reliability while at the same time reducing expenditure and investment. In the last few years it has become evident through the development of maintenance concepts that maintenance is more than just a non-productive support function, it is a profit- generating function. In the past decades, hundreds of models that address maintenance strategy have been presented. The vast majority of those models rely purely on mathematical modeling to describe the maintenance function. Due to the complex nature of the maintenance function, and its complex interaction with other functions, it is almost impossible to accurately model maintenance using mathematical modeling without sacrificing accuracy and validity with unfeasible simplifications and assumptions. Analysis presented as part of this thesis shows that stochastic simulation offers a viable alternative and a powerful technique for tackling maintenance problems. Stochastic simulation is a method of modeling a system or process (on a computer) based on random events generated by the software so that system performance can be evaluated without experimenting or interfering with the actual system. The methodology developed as part of this thesis addresses most of the shortcomings found in literature, specifically by allowing the modeling of most of the complexities of an advanced maintenance system, such as one that is employed in the airline industry. This technique also allows sensitivity analysis to be carried out resulting in an understanding of how critical variables may affect the maintenance and asset management decision-making process. In many heavy industries (e.g. airline maintenance) where high utilization is essential for the success of the organization, subsystems are often of a rotable nature, i.e. they rotate among different systems throughout their life-cycle. This causes a system to be composed of a number of subsystems of different ages, and therefore different reliability characteristics. This makes it difficult for analysts to estimate its reliability behavior, and therefore may result in a less-than-optimal maintenance plan. Traditional reliability models are based on detailed statistical analysis of individual component failures. For complex machinery, especially involving many rotable parts, such analyses are difficult and time consuming. In this work, a model is proposed that combines the well-established Weibull method with discrete simulation to estimate the reliability of complex machinery with rotable subsystems or modules. Each module is characterized by an empirically derived failure distribution. The simulation model consists of a number of stages including operational up-time, maintenance down-time and a user-interface allowing decisions on maintenance and replacement strategies as well as inventory levels and logistics. This enables the optimization of a maintenance plan by comparing different maintenance and removal policies using the Cost per Unit Time (CPUT) measure as the decision variable. Five different removal strategies were tested. These include: On-failure replacements, block replacements, time-based replacements, condition-based replacements and a combination of time-based and condition-based strategies. Initial analyses performed on aircraft gas-turbine data yielded an optimal combination of modules out of a pool of multiple spares, resulting in an increased machine up-time of 16%. In addition, it was shown that condition-based replacement is a cost-effective strategy; however, it was noted that the combination of time and condition-based strategy can produce slightly better results. Furthermore, a sensitivity analysis was performed to optimize decision variables (module soft-time), and to provide an insight to the level of accuracy with which it has to be estimated. It is imperative as part of the overall reliability and life-cycle cost program to focus not only on reducing levels of unplanned (i.e. breakdown) maintenance through preventive and predictive maintenance tasks, but also optimizing inventory of spare parts management, sometimes called float hardware. It is well known that the unavailability of a spare part may result in loss of revenue, which is associated with an increase in system downtime. On the other hand increasing the number of spares will lead to an increase in capital investment and holding cost. The results obtained from the simulation model were used in a discounted NPV (Net Present Value) analysis to determine the optimal number of spare engines. The benefits of this methodology are that it is capable of providing reliability trends and forecasts in a short time frame and based on available data. In addition, it takes into account the rotable nature of many components by tracking the life and service history of individual parts and allowing the user to simulate different combinations of rotables, operating scenarios, and replacement strategies. It is also capable of optimizing stock and spares levels as well as other related key parameters like the average waiting time, unavailability cost, and the number of maintenance events that result in extensive durations due to the unavailability of spare parts. Importantly, as more data becomes available or as greater accuracy is demanded, the model or database can be updated or expanded, thereby approaching the results obtainable by pure statistical reliability analysis.
3
Conrad, George R. "Development of course outlines for a maintenance technician training program". CSUSB ScholarWorks, 1985. https://scholarworks.lib.csusb.edu/etd-project/415.
Testo completo
4
Clark, David. "Terotechnology : its application to the Australian coal mining industry". Thesis, Queensland University of Technology, 1995. https://eprints.qut.edu.au/36236/1/36236_Clark_1995.pdf.
Testo completoAbstract (sommario):
Tererotechnology evolved between 1970 and 1975. In 1968 PA Management Consultants Ltd., was commissioned by the then Minister of Technology of the UK to carry out a study of engineering maintenance in British manufacturing industry.
It reported that:-
a) the total direct cost of engineering maintenance was approximately 1, 100 Million Pounds per annum (circa 1968)
b) improved productivity of maintenance staff could have led to a reduction in
maintenance expenditure of around 250 Million Pounds per annum.
c) better maintenance could have saved about 300 Million Pounds per annum of lost
production caused by unavailability.
Using this and other information a UK Ministry of Technology working party reporting in 1970 emphasised among other things, the importance of the link between maintenance costs and the feedback of information to the designers of the plant. A steering committee ( The Committee for Terotechnology) was then set up to examine the broader findings of this report and in 1972
published their conclusions, central to which was the statement - "the nature of the maintenance activity was determined by the manner in which plant and equipment was designed, selected, installed, commissioned, operated, removed and replaced. Major benefits could come to British Industry from the adoption of a broadly based technology which embraces all these areas, and because no suitable word exited to describe such a multidisciplinary
concept, the name "terotechnology" (based on the Greek word "terin" - to look after) was adopted." In 1975 the Committee for Terotechnology defined terotechnology as follows:- " a combination of management, financial, engineering and other practices applied to physical assets in pursuit of economic life cycle costs."
The following was then added: " .... its practice is concerned with the specification and design for reliability and maintainability of plant , machinery equipment, buildings and structures, with their
installation and replacement, and with the feedback of information on design, performance and costs." (1)
The definition was subsequently utilised in BS.3811 1984.
The concept ofterotechnology is therefore, a total concept, colloquially called whom to tomb.
The Australian underground coal mining industry is a. two billion dollar a year industry, contributing greatly to the Australian economy, particularly the export economy. Appendix CI-1 gives an overview of the industry. (2)
Having spent over 30 years in the industry, most of which was in engineering and maintenance, I was acutely aware that the industry committed many millions of dollars maintaining its plant and equipment. I was also aware that the equipment design was, in the main, maintenance
unfriendly. Also, equipment failures were responsible for many lengthy and expensive delays resulting in interruptions to the production process and loss of production.
Whilst many endeavours were made to improve the situation, I became persuaded that a much deeper problem existed, the results of which were being addressed but little effort seemed to be spent on addressing the fundamental causes of the problems resulting in equipment downtime and its consequences. Having been exposed to the discipline of terotechnology through studies for a Graduate Diploma in Maintenance Management (Terotechnology), I sought to study the industry's perception of itself in the terotechnological perspective. This resulted in my initial industry survey in 1985, of its maintenance and its management. The results identified that indeed a problem did exist but
needed a more indepth and expanded industry analysis for the real details to be quantified. To my knowledge, no previous research has been conducted into the terotechnological aspects of the coal mining industry.
Consequently, the research was commenced through QUT for a Master of Engineering Degree.
This Thesis is the results of that research.
The research sought to address the fundamental issues addressed in the UK study and to determine if indeed similar savings could be achieved in the Australian coal industry. That is a) to determine the cost of engineering maintenance b) to detennine the maintenance cost savings achievable if maintenance could be improved.
c) to determine the costs of lost production costs through maintenance causes.
The research commenced by issuing a survey document in 1989 and followed this up with detailed analysis of coal industry records. Two visits to the USA in 1991 and 1992, to discuss
equipment performance and design with designers and users also contributed to the research.
The underground coal mining industry uses two basic methods of mining to mine the coal in Australia. One is Bord and Pillar extraction method using continuous miner systems and the other is Longwall extraction methods. The research concentrated heavily on continuous miners as they were identified as having the greatest impact on maintenance and productivity in the immediate
future. Longwall is the technology of the future analysed but to a lesser extent than continuous miners, as a detailed industry analysis was being conducted by the coal industry of this technology during my research of continuous miners. The Australian underground coal mining industry is being forced to become more world wide
competitive than at any time in its history. It follows therefore, that whatever the technology used
to produce the coal, the four elements of:-
a) Fit for purpose equipment b) Competent people
c) Safe work procedures
d) Controlled work environment
must be addressed. This is consistent with the terotechnological approach of this research.
Results of the research follow in this document.
5
Elwany, Alaa H. "Sensor-based prognostics and structured maintenance policies for components with complex degradation". Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/37198.
Testo completoAbstract (sommario):
We propose a mathematical framework that integrates low-level sensory signals from monitoring engineering systems and their components with high-level decision models for maintenance optimization. Our objective is to derive optimal adaptive maintenance strategies that capitalize on condition monitoring information to update maintenance actions based upon the current state of health of the system. We refer to this sensor-based decision methodology as "sense-and-respond logistics".
As a first step, we develop and extend degradation models to compute and periodically update the remaining life distribution of fielded components using in situ degradation signals. Next, we integrate these sensory updated remaining life distributions with maintenance decision models to; (1) determine, in real-time, the optimal time to replace a component such that the lost opportunity costs due to early replacements are minimized and system utilization is increased, and (2) sequentially determine the optimal time to order a spare part such that inventory holding costs are minimized while preventing stock outs.
Lastly, we integrate the proposed degradation model with Markov process models to derive structured replacement and spare parts ordering policies. In particular, we show that the optimal maintenance policy for our problem setting is a monotonically non-decreasing control limit type policy. We validate our methodology using real-world data from monitoring a piece of rotating machinery using vibration accelerometers. We also demonstrate that the proposed sense-and-respond decision methodology results in better decisions and reduced costs compared to other traditional approaches.
6
Saxena, Abhinav. "Knowledge-Based Architecture for Integrated Condition Based Maintenance of Engineering Systems". Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16125.
Testo completoAbstract (sommario):
A paradigm shift is emerging in system reliability and maintainability. The military and industrial sectors are moving away from the traditional breakdown and scheduled maintenance to adopt concepts referred to as Condition Based Maintenance (CBM) and Prognostic Health Management (PHM). In addition to signal processing and subsequent diagnostic and prognostic algorithms these new technologies involve storage of large volumes of both quantitative and qualitative information to carry out maintenance tasks effectively. This not only requires research and development in advanced technologies but also the means to store, organize and access this knowledge in a timely and efficient fashion. Knowledge-based expert systems have been shown to possess capabilities to manage vast amounts of knowledge, but an intelligent systems approach calls for attributes like learning and adaptation in building autonomous decision support systems.
This research presents an integrated knowledge-based approach to diagnostic reasoning for CBM of engineering systems. A two level diagnosis scheme has been conceptualized in which first a fault is hypothesized using the observational symptoms from the system and then a more specific diagnostic test is carried out using only the relevant sensor measurements to confirm the hypothesis. Utilizing the qualitative (textual) information obtained from these systems in combination with quantitative (sensory) information reduces the computational burden by carrying out a more informed testing. An Industrial Language Processing (ILP) technique has been developed for processing textual information from industrial systems. Compared to other automated methods that are computationally expensive, this technique manipulates standardized language messages by taking advantage of their semi-structured nature and domain limited vocabulary in a tractable manner.
A Dynamic Case-based reasoning (DCBR) framework provides a hybrid platform for diagnostic reasoning and an integration mechanism for the operational infrastructure of an autonomous Decision Support System (DSS) for CBM. This integration involves data gathering, information extraction procedures, and real-time reasoning frameworks to facilitate the strategies and maintenance of critical systems. As a step further towards autonomy, DCBR builds on a self-evolving knowledgebase that learns from its performance feedback and reorganizes itself to deal with non-stationary environments. A unique Human-in-the-Loop Learning (HITLL) approach has been adopted to incorporate human feedback in the traditional Reinforcement Learning (RL) algorithm.
7
Matejová, Alexandra. "Návrh na zlepšenie starostlivosti o dlhodobý hmotný majetok v strojárenskej výrobe". Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2015. http://www.nusl.cz/ntk/nusl-224849.
Testo completoAbstract (sommario):
This master thesis focuses on the issue of tangible fixed assets management in the company HP spol. s r.o. which manufactures plastic bags and various technical parts. This thesis is based on the current state of the company and with attention to key areas such as care of the tangible fixed assets, organization and operation maintenance. The aim of the company analysis is to identify weaknesses and their resulting opportunities. In the next section are presented solutions to problems which were identified by analysis. Economic evaluation of the proposals with their benefits and timetable is carried out in conclusion of the thesis.
8
Klopper, Marthinus Ferreira. "The life expectancy of heavy earthmoving equipment on a sand dune mine in a highly corrosive environment". Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/80762.
Testo completoAbstract (sommario):
Thesis (MBA)--Stellenbosch University, 2004.ENGLISH ABSTRACT: Richards Bay Minerals (RBM) went through a restructuring process in 2002. The effect that these changes had on the life expectancy of the heavy earthmoving equipment (HEME) at the company’s sand dune mining operation situated at Richard’s Bay on the north coast of KwaZulu-Natal, was unknown. This study explores these, and various other factors, that influence the life expectancy of the HEME in this highly corrosive environment. During the last number of years there has been no equipment replacement philosophy at RBM and this has resulted in the average age of HEME at the mine being extremely high. This study suggests that when restructuring is implemented in the wrong way, the process can have significant negative implications. The study determines how the behaviour of especially drivers and maintenance personnel (maintainers) impacts on the expected life of the HEME at RBM. The hidden cost element of driver and maintainer unhappiness, however, is not included as part of this study. In the first part of this study project, the writer focuses on what may have caused the unhappiness, and makes suggestions for further studies aimed at addressing this unhappiness and changing the behaviour of drivers and maintainers. These suggestions should be seen as guidelines, as measures that work in one company may not necessarily work in another. The second part of the study project deals with the replacement philosophy regarding HEME at RBM. The mine has various types of equipment, but the main focus of this research falls on the following: Caterpillar 966- 980 (payloaders), track type equipment Caterpillar D7R/H (dozers), Caterpillar 988- 992 (heavy duty payloaders) and Bell B25 articulated dumptrucks (dumptrucks) Four different replacement models are investigated and discussed in detail. The model that was best aligned with the Caterpillar proposed best replacement practice, as stipulated by the Caterpillar replacement expert, is identified. Finally, a replacement cycle for the different types of equipment is proposed.
AFRIKAANSE OPSOMMING: Richardsbaai Minerale (RBM) het in 2002 deur ‘n herstruktureringsprogram gegaan. Die uitwerking wat die gevolge daarvan op die swaar grondverskuiwingsvoertuie (SGV) gehad het was onbekend. Gedurende die laaste aantal jare was daar geen vervangingsbeleid by RBM nie, en dit het meegebring dat die gemiddelde ouderdom van die SGV op die myn buitengewoon hoog is. Dit is belangrik om te bepaal wat die invloed van menslike gedrag van veral die drywers en herstelpersoneel op die verwagte leeftyd van SGV is. Die versteekte koste wat verbind word met ongelukkige drywers en herstelpersoneel maak nie deel uit van hierdie studie nie. As herstrukturering op die verkeerde manier toegepas word kan dit ‘n negatiewe impak hê. In die studie sal daar aandag gegee word aan wat die negatiewe elemente is en wat is die moontlike oorsaak daarvan. Daar word ook sekere voorstelle gemaak vir toekomstige studies om die ongelukkigheid aan te spreek en ‘n gedragsverandering na vore te bring. Die voorstelle is slegs riglyne en, wat in een maatskappy werk sal nie noodwendig in ‘n ander een werk nie. Die tweede deel van die werkstuk fokus op vervangingsteorieë met betrekking tot die SGV op RBM. Die myn het verskeie tipes SGVs maar die fokus het geval op vier soorte SGV. Hulle is Caterpillar 966- Caterpillar 980 (gemiddelde laaiers), spoor tipe toerusting Caterpillar D7R/H (stootskrapers), Caterpillar 988- Caterpillar 992 (swaargewig mobiele laaiers) en Bell B25 geartikuleerde stortings trokke (stortings trokke). Vier verskillende modelle is ondersoek en deeglik bespreek. Die model met die beste uitslae wat die mas opgekom het ten opsigte van die Caterpillar se voorgestelde beste vervangings praktyk, soos aangedui deur die Caterpillar voertuig vervangings kenner, is ge-identifiseer. Laastens word die vervangingsiklus vir die verskillende tipes toerusting voorgestel.
9
Van, den Berg Gideon. "Hidden Markov models for tool wear monitoring in turning operations". Diss., Pretoria : [s.n.], 2004. http://upetd.up.ac.za/thesis/available/etd-05302005-114238/.
Testo completo
10
Tada, Mariko. "Design and development of a standardized Mitsubishi PLC program troubleshooting and repair training manual for machine maintenance personnel at TTAI". Online version, 2004. http://www.uwstout.edu/lib/thesis/2004/2004tadam.pdf.
Testo completo
11
Skálová, Hana. "Návrhy na zlepšení hospodaření s dlouhodobým hmotným majetkem". Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2012. http://www.nusl.cz/ntk/nusl-223653.
Testo completoAbstract (sommario):
This thesis is focused on analysis of production facilities utilization and maintenance in the company RAMET C.H.M. a.s. located in Kunovice. In this thesis, there is performed the analysis of present property condition, machinery and equipment used within radar antenna production. Within property maintenance, there are introduced planned and unplanned processes of servicing activities and machine and equipment repair. In a part of proposal for solution, there are recommended processes for keeping up production capabilities based on extensive analysis of size property influence on production volume. The method for reliability estimation of production chain is described for the antenna production, related to limiting production capability and costs to maintain service availability of production facilities.
12
Chaloupková, Veronika. "Návrhy na zlepšení hospodaření s dlouhodobým hmotným majetkem". Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2017. http://www.nusl.cz/ntk/nusl-319433.
Testo completoAbstract (sommario):
This Master thesis deals with the management of long-term tangible property in the company Česko-slezská výrobní, a. s., which is engaged in manufacturing of portable and sanitary cabins. The thesis is divided into three parts. The first part describes the theoretical background, which forms the theoretical base of the whole thesis. The second part is focused on analysis of the current situation of long-term tangible property in the company and property maintenance. The result of the analysis is identification of weaknesses and opportunities for development. In the last part are proposed solution including economic evaluation and time-consuming.
13
Leme, Murilo Oliveira. "Metodologia de manutenção preditiva para motores elétricos baseada em monitoramento de variáveis físicas e análise multicritério". Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2905.
Testo completoAbstract (sommario):
Este trabalho apresenta o desenvolvimento de uma metodologia de manutenção preditiva para motores elétricos, que utiliza a técnica de monitoramento de variáveis, transmissão de dados pela rede elétrica (Powerline Communication) e um tratamento com os métodos multicritério para classificação (ELECTRE TRI e AHPSort) e ordenação (ELECTRE II) dos motores que apresentam condição de falha incipiente, além do aproveitamento das instalações elétricas existentes para a aquisição de dados do funcionamento de motores elétricos tais como: tensão, corrente, temperatura e vibração. Essas informações podem ser avaliadas e tratadas através de métodos multicritério para alocar os motores em classes que representam estados de funcionamento normal, aceitável e falha incipiente. Assim, nos motores classificados em condição de falha incipiente pode ser realizado um ranking para apontar o motor em pior estado de funcionamento. Neste trabalho, foi conduzido um ensaio de falhas programadas em bancada com um período de aquisição de 1 minuto das variáveis de funcionamento de seis motores. Neste período, pode ser feito o registro do motor que apresentou as condições mais críticas para a falha, considerando as variáveis medidas como critérios na análise. Após um largo período de análise, foram computadas todas as vezes que cada motor foi classificado na classe de falha incipiente e ranqueado em primeiro lugar, significando que ele possui condições fora do padrão normal de funcionamento e piores que dos outros motores analisados. Com isso, foi possível identificar o motor que, por mais vezes, esteve em condição de falha incipiente, refletindo as falhas inseridas durante o ensaio. Essa metodologia possibilitou indicar ao gestor da manutenção, os desvios do funcionamento normal de motores elétricos, considerando mais de uma variável ao mesmo tempo, alinhado aos objetivos do decisor, através dos pesos calculados para os critérios, limites e preferências estabelecidas em cada método multicritério utilizado na metodologia proposta neste trabalho.This work presents the development of a predictive maintenance methodology for electric motors, which uses the variable monitoring technique, data transmission through the electric network (Powerline Communication) and a treatment with multicriteria methods for sorting (ELECTRE TRI and AHPSort) and ranking (ELECTRE II) electric motors with incipient failure condition and the use of existing electrical installations for the acquisition of data of the operation of electric motors such as voltage, current, temperature and vibration. This information can be evaluated and treated through multicriteria methods to allocate motors in classes that represent normal, acceptable, and incipient failure states. Thus, in electric motors classified as incipient failure condition, a ranking can be performed to detect the engine in the worst operating state. In this work, a bench experiment was conducted with a 1-minute acquisition period of the operating variables in 6 motors. In this period, the electric motor can be registered that presented the most critical conditions for the fault, considering the measured variables as criteria in the analysis. After a longer period of analysis, we computed every time this engine was classified in the incipiente failure and first rank class, which means that it has conditions that are out of the normal operating range and worse than the other engines analyzed. Through this methodology it is possible to indicate to the maintenance manager deviations from the normal operation of electric motors, considering more than one variable at the same time aligned to the objectives of the decision maker, through the weights calculated for the criteria and limits and preferences established in each multicriteria method used in the methodology proposed in this work.
14
Joseph, Mathews. "Failure analysis in a paper mill and a coal conveyor system". Thesis, Queensland University of Technology, 1996. https://eprints.qut.edu.au/36003/1/36003_Joseph_1997.pdf.
Testo completoAbstract (sommario):
This thesis aims at explaining two different methods by which failure analysis can
be conducted . The two methods were used in two totally different circumstances.
One was the failure study conducted at the Petrie Mill of Australian Paper and the
other was a study of conveyor belt failures based on the author's experience at
Neyveli Lignite Corporation Limited. The bottom line is to stress the need for
separate strategies depending on the nature of industry or the machinery and the
importance of documenting the actual Failure Analysis however it may be done.
This will help in further development of the strategies and provide ideas for
newcomers in the field. Using the data obtained by applying strategy-1 Reliability
Analysis and Planned Replacement cost analysis can be conducted. Two
components selected by applying strategy-I were analysed using Relcode and are
included in this thesis. Three other major initiatives associated with this research are
Failure Recording and Spare Control system (FR&SC) for Petrie Mill, Belt
Condition Recording and Monitoring system(BEL TCON) and Conveyor Belt
Breakdown Maintenance Management flow chart for users of conveyor belts. All of
these concepts, presently in a flow-chart form, can be programmed and further
developed into a full-fledged software package. They will definitely be very handy
tools for engineers and managers who deal with similar situations. The power of
FM-EAsy software is utilized in analysing the failures in conveyor belt systems,
which involves the recording of all failure modes, effects and criticality.
15
Carson, Christian Tyler. "DNA viruses and the cellular DNA repair machinery /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2005. http://wwwlib.umi.com/cr/ucsd/fullcit?p3175282.
Testo completo
16
Gilk, Jiří. "Návrhy na zlepšení hospodaření s dlouhodobým majetkem". Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2012. http://www.nusl.cz/ntk/nusl-223503.
Testo completoAbstract (sommario):
This dissertation solves the problems with management of capital goods in the company FORMIRA, s.r.o. The dissertation is elaborated from the analysis of present situation in the plant, whereas the heed is oriented to the most important areas, especially the organization and service activity and maintenance of assets. The result of performed analysis is the identification weak points. Proposals are submitted in the second part of the dissertation, in order to solve the problems found by presented analysis. The economical evaluation of the proposals and determinations of assumptions for the application of extended results to the company use is performed at the end of the dissertation.
17
Černá, Pavlína. "Návrhy na zlepšení hospodaření s dlouhodobým hmotným majetkem". Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2014. http://www.nusl.cz/ntk/nusl-224615.
Testo completoAbstract (sommario):
This thesis focuses on issue of tangible fixed assets management in the company DT – Vyhybkarna a strojirna a.s. in the Prostejov city. This company produces, installs and restores turnout trackwork for railways, trams and underground tracks. The first part of this thesis analyses current situation of tangible assets and its handling, based on the evaluation of the maintenance department. Afterwards it defines weak parts and reveals shortages, on which an improvement suggestions for optimalizing and melioration of that state is made. At the end of this thesis is made an economic evaluation of the suggestions and expected changes in case of the implementation.
18
Al-kaabi, Hamad A. "Airlines' maintenance, repair and overhaul (MRO) configurations". Thesis, Cardiff University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437225.
Testo completo
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Osman, Mohamud Maria, e Ubilla Fernanda Sanchez. "Ultraljudsutbildningar för medicintekniska ingenjörer : Behovsinventering, inköpsprocedurer och effekter". Thesis, KTH, Medicinteknik och hälsosystem, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298194.
Testo completoAbstract (sommario):
Denna studie syftar till att undersöka hur ultraljudsutbildningar för ingenjörer köps in, vad de innehåller, hur de genomförs, utvärderas och vilka resultatutbildningarna leder till. Totalt intervjuades sex sjukhus runt om i Sverige där elva medicintekniska ingenjörer och fyra verksamhetschefer deltog. En kvalitativ metod användes i studien i form av semistrukturerade intervjuer som grund för att analysera frågeställningarna. Resultatet visade att utbildningar köps in i upphandling av nya ultraljudsmaskiner och genomförs under garantiåren. Utbildningarna hålls av leverantörerna och de brukar vara i två dagar. Effekterna av utbildningarna varierar och beror på vilket serviceavtal som sjukhusen har. Det saknas en formell modell för utvärdering och uppföljning, trots det faktum att det i årliga möten diskuteras hur utbildningarna har gått och vilka kompetenser som behövs. Resultatet från studien kan främst användas i syfte att skapa bättre utbildningar, underlätta kommunikationen mellan sjukhus och leverantör om vad kursen innebär, samt vad ingenjörerna föredrar för innehåll i kurser för att kunna utvecklas inom ultraljud.This study aims to investigate how ultrasound training for engineers is purchased, including how it is carried out and evaluated, what the different courses contain and what result the courses lead to. Six hospitals around Sweden were interviewed, where eleven medical engineers and four business managers participated. A qualitative method was used in the study with semi-structured interviews as a basis for analysing the issues. The results showed that the training courses are purchased in the procurement of new ultrasound machines and are carried out during the warranty years. The suppliers hold the training courses, which are usually held for two days. The effects of training vary and depend on the service agreement that the hospitals have. There is no formal model for evaluation and follow-up, even though annual meetings discuss how the training has gone and what skills are needed. The results can mainly be used to create better training and improve communication between hospital and supplier about what the course entails and what the engineers prefer for the content of courses to develop in the area.
20
Bridges, Michael R. "Optimally funding Army Installation repair and maintenance activities". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA341063.
Testo completoAbstract (sommario):
Thesis (M.S. in Operations Research) Naval Postgraduate School, September 1997."September 1997." Thesis advisor(s): Robert F. Dell. Includes bibliographical references (p. 43-44). Also available online.
21
Nikou, Vasilios 1972. "Welded repair and maintenance in the space environment". Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/91796.
Testo completoAbstract (sommario):
Thesis (Nav.E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2003.Includes bibliographical references (leaves 73-75).
by Vasilios Nikou.
Nav.E.
S.M.
22
Kelly, Annette. "Comparative analysis of intermediate level maintenance repair process". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FKelly.pdf.
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Jimoh, Mohammed Tajudeen. "A vision for MPC performance maintenance". Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/4739/.
Testo completoAbstract (sommario):
Model predictive control (MPC) is an advanced control that has found widespread use in industries, particularly in process industries like oil refining and petrochemicals. Although the basic premise behind MPC is easy to comprehend, its inner workings are still generally viewed or regarded as too advanced for actual plant operator understanding. This lack of understanding is exposed when MPC performance deteriorates sometime after commissioning, as is often the case in some commercially operated process plants. Currently operators might have difficulty over reasoning about MPC performance degradation and formulating steps to investigate the cause. A tool is described that aims to make MPC more transparent to the operators. Commonly reported causes of MPC performance degradation are discussed and ways in which the operator can recognise them when they occur are outlined. Issues that are addressed include: making the set of controlled variables to be used for a given set of manipulated variables simpler and clearer; ways to recognise when a MPC controller is performing poorly and to identify the source of performance deterioration. An aim is to determine under what instances the operator can return the MPC performance to previous levels or request for specialist support or simply switch the MPC off. A goal is to avoid the kind of often reported situation where the operator gets worried that the controller is deteriorating and ends up taking knee jerk actions that cause further problems in MPC. At the top of the maintenance tool hierarchy is the trends comparison group, where MPC reference graphical performance trends are compared with actual graphical performance trends counterpart. If any abnormality is observed in these trends, the operator is encouraged to choose an option from a list of preliminary diagnostic questions contained in a group below trends comparison group, which best describes the observed abnormality. Each abnormality is associated with a list of suspected causes. When a suspected cause is chosen from the associated list, the operator is led to the symptoms investigation window, which contains scripts detailing steps for systematic examination of each symptom, with a view to either rejecting or confirming the suspicion. Assisted in the investigation are four background information windows: the virtual plant without MPC window, the virtual plant with MPC window, the transfer function matrix window and steady state gain, relative gain array (RGA) and relative weight array (RWA) window. The windows contain information and guidance that the operator might refer to from time to time during symptom investigation. Development of the maintenance tool is still at the design stage. The key components described have been research implementing MPC on three nonlinear process models, a continuous stirred tank reactor (CSTR), an evaporator process and a fluid catalytic cracking unit (FCCU). Case studies representing different MPC degradation scenarios are simulated, followed by a systematic procedure for diagnosing, isolating and recovering from such degradation, based on assumed operator’s perspective and expert’s technical reasoning. The knowledge gained from the case studies is used to develop an outline of a vision for a data-driven model predictive maintenance tool to help the operator make sensible judgements about performance degradation, the form and direction of diagnosis and fault isolation, and possibly, the recovery procedure.
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Proença, Sara Salgueiro. "Organization of the maintenance : method to implement a maintenance management system and methodology for efficient maintenance on heavy machinery". Master's thesis, Instituto Politécnico de Setúbal. Escola Superior de Tecnologia de Setúbal, 2019. http://hdl.handle.net/10400.26/31375.
Testo completoAbstract (sommario):
Relatório de Dissertação do Mestrado em Engenharia de ProduçãoEste trabalho dá início à construção de um método para implementação de um sistema de gestão da manutenção e é também um estudo de organização e disponibilidade de máquinas pesadas. A pesquisa tem como fundamento base a manutenção e todas as questões inerentes a esta. Irá descrever e salientar a importância da manutenção e resolução de problemas nos dias de hoje nas empresas. Para o sector específico da manutenção de máquinas pesadas, apresento uma proposta de organização com o objetivo de fazer melhor uso dos recursos humanos e materiais. O trabalho será apresentado como um estudo de caso geral. Perante os modelos existentes de manutenção, a realidade, o propósito / finalidade, princípios e ferramentas, apresento novas perspetivas de como atuar e desenvolver o trabalho que permita encontrar a melhor forma de fazer a gestão da manutenção eficiente e eficaz. No desenvolvimento do trabalho é importante conhecer todas as variáveis da manutenção porque apesar desta ser planeada podem existir e / ou verificar-se desvios do planeamento, o que acontece com alguma frequência. A criação de uma metodologia de implementação de um sistema tem como objetivo não só a sua implementação, mas também a eliminação de falhas e a procura da melhoria continua. Após conhecer bem a manutenção é tempo de começar uma nova pesquisa para o desenvolvimento do sistema em si. Na continuação deste trabalho, serão criados procedimentos e apoio à decisão, a fim de sustentar a organização da manutenção e o sistema de gestão da mesma. Este estudo foi realizado para três tipos de equipamentos: escavadora, máquina florestal e pá carregadora de rodas).
This paper is the beginning of the construction of a method for implementation of a maintenance management system and a study organization and availability of heavy machines. It is a research of base fundaments of maintenance and all the issues that arise from the maintenance. It will describe the importance of maintenance on these days to the companies and their problems with maintenance. A specific sector, maintenance of heavy machinery with the proposal to organized, to make better use of human and material resources, will be presented as a general case study. Given the maintenance models, the reality, the end of destination, principles and tools, a new perspective, how to act and develop the work in order to find the best ways to perform the maintenance management in an effective and efficient manner will arise. It is important to know all the variables of maintenance. Because even if maintenance is planned deflections of the plan can be possible and that happens very often. The creation of a methodology to the implementation of the system aims its implementation and therefore the elimination of waste and always looking for improvement. Now that we know well the maintenance the question is the time to begin a new research for the development of the system itself. On the continuing of this work procedures and decision supports will be created in order to sustain the maintenance organization and the maintenance management system focussing on specialised equipment’s (excavator, forest machine and wheel loader).
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Toves, Peter Rocky. "Evaluating Success Factors in Implementing E-Maintenance in Maintenance, Repair, and Overhaul (MRO) Organizations". ScholarWorks, 2015. https://scholarworks.waldenu.edu/dissertations/767.
Testo completoAbstract (sommario):
Despite more than a decade-long process to transition aircraft maintenance practices from paper-to electronic-based systems, some organizations remain unable to complete this transition. Researchers have indicated that while organizations have invested resources in technology improvements, there remains a limited understanding of the factors that contribute to effectively managing technology-enabled change. The purpose of this case study was to identify and explore socio-technical (ST) factors that inhibit an effective transition from a paper-based system to an electronic-based system for aircraft maintenance. A conceptual model applying theories of change management, technology acceptance, systems thinking, and ST theory informed the research. Thirteen participants provided data via semistructured interviews, field observations, follow-up interviews, other documentation, and a questionnaire. Data were analyzed with open and axial coding techniques to identify themes, which were then crosschecked and triangulated with observation and follow-up interview data. Findings revealed communication issues, a fundamental misconception in training, and a false assumption that all personnel easily acquire computer literacy. Benefits gained from this study should assist maintenance, repair, and overall (MRO) organizations within the Department of Defense to improve current and future technology implementation as the research underscores real-life issues from a comparable organization. The implications for positive social change provide a greater understanding of technology-enabled change and contribute to the development of best practices for technology initiatives that address common ST issues in the MRO workplace.
26
Luyt, Leslie. "Automated grid fault detection and repair". Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1006693.
Testo completoAbstract (sommario):
With the rise in interest in the field of grid and cloud computing, it is becoming increasingly necessary for the grid to be easily maintainable. This maintenance of the grid and grid services can be made easier by using an automated system to monitor and repair the grid as necessary. We propose a novel system to perform automated monitoring and repair of grid systems. To the best of our knowledge, no such systems exist. The results show that certain faults can be easily detected and repaired.TeX
Adobe Acrobat 9.51 Paper Capture Plug-in
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Shaheen, Fadhel Sulaiman. "Targeting the DNA double strand break repair machinery in prostate cancer". Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500921.
Testo completoAbstract (sommario):
Prostate cancer is the most common cancer in males in western societies. In spite of the successful first line treatment using surgery, radiation therapy, antiandrogen treatment or combination therapy the disease progresses towards a hormone refractory state where the only effective treatment is chemotherapy which prolongs overall survival, however it is not curative. The resistance that hormone refractory disease displays highlights the importance of developing new targeted therapies which may be curative or at least may improve the patient's quality of life and overall survival. Current chemotherapeutic regimens used in prostate cancer treatment mostly contain agents that induce DNA damage and specifically double strand breaks, such as Doxorubicin, mitoxantrone and etoposide.
28
Lee, Hock Guan. "A study on predictive analytics application to ship machinery maintenance". Thesis, Monterey California. Naval Postgraduate School, 2013. http://hdl.handle.net/10945/37659.
Testo completoAbstract (sommario):
Approved for public release; distribution is unlimitedEngine failures on ships are expensive, and affect operational readiness critically due to long turn-around times for maintenance. Prior to the engine failures, there are signs of engine characteristic changes, for example, exhaust gas temperature (EGT), to indicate that the engine is acting abnormally. This is used as a precursor towards the modeling of failures. There is a threshold limit of 520 degree Celsius for the EGT prior to the need for human intervention. With this knowledge, the use of time series forecasting technique, to predict the crossing over of threshold, is appropriate to model the EGT as a function of its operating running hours and load. This allows maintenance to be scheduled just in time. When there is a departure of result from the predictive model, Cumulative Sum (CUSUM) Control charts can then be used to monitor the change early before an actual problem arises. This paper discusses and demonstrates the proof of principle for one engine and a particular operating profile of a commercial vessel with the use of predictive analytics. The realization with time series forecasting coupled with CUSUM control chart allows this approach to be extended to other attributes beyond EGT.
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Gamede, Cyril Vuyani. "Boiler maintenance using expert systems". Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/18798.
Testo completoAbstract (sommario):
This research explores the application of expert systems to the maintenance of boilers, are as follows: and its main objectives [1] To explore the application of expert systems in the maintenance of boilers. [2] To simplify the task of boiler maintenance with the help of expert systems. [3] To improve the skills of boiler maintenance workers through the knowledge 'captured ' or 'preserved' by expert systems. [4] To minimise errors which may cost time, money, effort and possible risk of injury to boiler maintenance personnel. [5] To develop a prototype expert system which can advise and assist boiler maintenance personnel. [6) To contribute to research in the application of expert systems in the field of engineering.
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Cash, M. Alex. "Detection of turn faults arising from insulation failure in the stator windings of AC machines". Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/15460.
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Li, Huan. "Damage and repair evolution of cold formed linepipe steel". Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/671/.
Testo completoAbstract (sommario):
The main aim of this research is to model the internal micro damage accumulated during cold deformation and the degree of reduction of damage that can be achieved by heat treatment of linepipe steel. A set of unified viscoplastic constitutive equations was developed to simulate microstructural evolution and the effect on mechanical properties due to cold deformation followed by annealing. In addition, practical experiments have been performed to validate the constitutive equations. Firstly, the industrial motivation for the project was previewed and damage-modelling techniques were reviewed to identify the research objectives. A group of interrupted uniaxial tensile tests were conducted to study the effect of different annealing times on reducing the degree of damage and improving mechanical properties of a cold formed single phase linepipe steel. From the experimental results, it was observed that healing by subsequent annealing enables a significant improvement in the mechanical properties of the deformed steel that has experienced only light damage, but has no significant effect on heavily damaged steel. Following this, a set of constitutive equations describing accumulation and annihilation of dislocations, grain size evolution, recrystallisation, plasticity induced damage and their effects on viscoplastic flow of materials was developed, for uniaxial stress conditions and by numerical integration experimental results were used to determine material constants for these equations, for the particular steel. Secondly, the constitutive equations were expanded to enable damage nucleation, growth and plastic flow to be predicted for various stress states. The constitutive equations were implemented in a commercial FE solver (ABAQUS) using the VUMAT user-subroutine. The numerical results reproduce the essential features of necking phenomena and provide a physical insight into damage evolution within a tensile testpiece under given necking conditions. Dual phase steel is of greater importance industrially, than a single phase steel, but because of the greater complexity in its microstructure, the development of microstructural constitutive equations for it is very difficult. Thus, in this work, some knowledge of damage initiation in a dual phase steel was obtained by practical investigation of microstructure. It showed that damage is due to ductile cracking characterised by the nucleation of micro-voids near the ferrite-pearlite interface. Using the mesoscopic modelling technique, by simulation, it was possible to determine likely sites for damage initiation.
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Haidvogel, Robert F. "The Afloat maintenance Command: organizational and funding issues in Navy ship maintenance, repair, and modernization". Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23521.
Testo completoAbstract (sommario):
Approved for public release; distribution is unlimitedThe goal of current Navy surface ship maintenance and repair strategy is to sustain readiness and to maximize both combat capability and the amount of time ships are available for employment during their lifetime. The established organizational framework of the Navy to perform this task includes a complex array of activities that are effective overall, but at the expense of efficiency. The current drawdown in budget resources requires that the goals of ship maintenance and modernization be met with improved efficiency. The Afloat Maintenance Command is a proposal to restructure the existing maintenance hierarchy. Improvements in the process of maintenance and modernization are incorporated in the Afloat Maintenance Command through the elimination of redundancies in capabilities and the improvement of funding flows to enhance organizational efficiency and effectiveness. This thesis will provide an overview of the Afloat Maintenance Command and its possible organization in consolidating assets from existing maintenance activities. Additionally, funding alternatives for the Afloat Maintenance Command will be developed and assessed.
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De, Wet Vorster Hendrik. "An analysis of the effectiveness of the asset maintenance plan at Spoornet : case study : class diesel locomotives (traction and rolling stock)". Thesis, Peninsula Technikon, 2001. http://hdl.handle.net/20.500.11838/1019.
Testo completoAbstract (sommario):
Thesis (MTech (Business Administration))--Peninsula Technikon, 2001Maintenance of locomotives is the main function of Bellville Locomotive Traction Depot in the Western Cape. Therefore, it is important to have a sound maintenance plan in place, to prevent a negative impact on the availability and reliability of locomotive supply for hauling power to train services. The purpose of the research is to determine the causes of the increased frequency of maintenance through a case study relating to 35-class locomotives. The abnormal increased frequency of wheel change and inter-bogie control repairs on 35-class diesel locomotives is investigated. A research survey was adopted, which included questionnaires and personal interviews based on the literature search. The target group is L&N section, which includes below-deck maintenance, overhaul and change out, repairs to locomotive bogies, frames, wheels, snubbers, inter-bogie control and traction motors. Sixteen people are responsible for all below-deck repairs and service of 52 locomotives. The results of the research will expose the shortcomings of the maintenance plan and propose solutions. This will be achieved by testing the effectiveness of the existing maintenance plan at Spoornet through the identification of the causes for the abnormal increase in wheel changes and inter-bogie control repairs on 35-class diesel locomotives. The outcome from this case study research will be to quantify the benefits arising from the effective application of a maintenance plan.
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An, Wei 1963. "Strengthening of concrete beams with composite plastic plates". Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/277246.
Testo completoAbstract (sommario):
This study investigates the feasibility of strengthening reinforced concrete beams with epoxy-bonded Glass-Fiber-Reinforced-Plastic (GFRP) plates. The composite plate is epoxy-bonded to the tension flange of the beam to increase its stiffness and strength. Seven rectangular and one T-beam, retrofitted with composite plates, were tested to failure under symmetrical 4-point bending. The load versus deflection and the load versus strain in the composite plate, steel rebar and the extreme compression fiber of concrete were measured and plotted for the midspan section throughout the entire range of loading up to failure. Analytical models based on the equilibrium of forces and compatibility of deformations were developed to predict the stresses and deformations of the beam in the linear and nonlinear regions. The predicted and measured results correlated well. The analytical models were used in a parametric study to investigate the effects of design variables such as, plate area, plate strength and stiffness, reinforcement ratio, etc., on the moment-curvature relationships of typical rectangular and T cross sections.
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盧英明 e Ying-ming Lo. "Analysis of maintenance service figures of domestic towngas appliance". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1991. http://hub.hku.hk/bib/B31976645.
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Iu, Lai-ling. "Slope mainteannce [i.e. maintenance] and repair works in Hong Kong". Click to view the E-thesis via HKU Scholars Hub, 2005. http://lookup.lib.hku.hk/lookup/bib/B37935392.
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Aman, Shah Shahani. "System level airborne avionics prognostics for maintenance, repair and overhaul". Thesis, Cranfield University, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/11844.
Testo completoAbstract (sommario):
The aim of this study is to propose an alternative approach in prognostics for
airborne avionics system in order to enhance maintenance process and aircraft
availability. The objectives are to analyse the dependency of avionic systems
for fault propagation behaviour degradation, research and develop methods to
predict the remaining useful life of avionics Line Replaceable Units (LRU),
research and develop methods to evaluate and predict the degradation
performances of avionic systems, and lastly to develop software simulation
systems to evaluate methods developed.
One of the many stakeholders in the aircraft lifecycle includes the Maintenance,
Repair and Overhaul (MRO) industry. The predictable logistics process to some
degree as an outcome of IVHM gives benefit to the MRO industry.
In this thesis, a new integrated numerical methodology called ‘System Level
Airborne Avionic Prognostics’ or SLAAP is developed; looking at a top level
solution in prognostics. Overall, this research consists of two main elements.
One is to thoroughly understand and analyse data that could be utilised.
Secondly, is to apply the developed methodology using the enhanced
prognostic methodology.
Readily available fault tree data is used to analyse the dependencies of each
component within the LRUs, and performance were simulated using the linear
Markov Model to estimate the time to failure. A hybrid approach prognostics
model is then integrated with the prognostics measures that include
environmental factors that contribute to the failure of a system, such as
temperature. This research attempts to use data that is closest to the data
available in the maintenance repair and overhaul industry.
Based on a case study on Enhanced Ground Proximity Warning System
(EGPWS), the prognostics methodology developed showed a sufficiently close
approximation to the Mean Time Before Failure (MTBF) data supplied by the Original Equipment Manufacturer (OEM). This validation gives confidence that
the proposed methodology will achieve its objectives and it should be further
developed for use in the systems design process.
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Tu, Yu-Chen. "Condition-based maintenance cost model". Diss., Online access via UMI:, 2006.
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Lia, Debora. "Role of alphaOGG1 in the Maintenance of Mitochondrial Physiology". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS125/document.
Testo completoAbstract (sommario):
Les mitochondries sont des structures uniques dans la cellule mammifère. Ces organites portent leur propre génome (ADN mitochondrial, ADNmt) qui se compose d'une petite molécule qui codifie pour 13 polypeptides de la chaîne de transport d'électrons (ETC), 22 ARNt et 2 gènes d'ARNr pour sa propre synthèse protéique. Le MTDNA est proposé pour être plus susceptible au stress oxydatif que le génome nucléaire (ADNn) parce que non seulement il manque d'histones protectrices, mais aussi en raison de sa proximité avec les complexes ETC qui sont les principaux producteurs de ROS dans les cellules de mammifères. Parmi tous les types de dommages à l'ADNmt, les dommages oxydatifs sont les plus répandus et, de loin, les mieux étudiés. La voie de réparation de l'excision de base (BER) est un mécanisme de réparation d'ADN conservé de façon évolutive qui répare les dommages de base d'ADN non volumineux. Puisque la guanine a le potentiel redox le plus bas de toute autre base dans l'ADN, elle est facilement oxydée à la 8-oxoguanine (8-oxoG) qui est l’altération la plus fréquente induite par les ROS sur les deux, l'ADNc et l'ADNmt. Si la fourche de réplication contourne le 8-oxoG avant son élimination, un A est souvent inséré sur le brin d'ADN opposé et les réplications subséquentes corrigent la transversion de G à T. Lorsqu'il est associé à la cytosine, le 8-oxoG est éliminé de l'ADN par l'ADN glycosylase de 8-oxoguanine (OGG1) qui, de cette manière, initie le procédé BER. OGG1 est une glycosylase de ménage bi fonctionnelle qui, conjointement avec d'autres enzymes BER différentes, est présente dans les compartiments nucléaires et mitochondriaux, soulignant l'importance de maintenir l'intégrité de l'ADNmt pour le fonctionnement cellulaire normal. Il a été démontré que la surexpression d'une version recombinante d'OGG1, spécifiquement destinée aux mitochondries par un signal de ciblage mitochondrial supplémentaire (MTS) (OGG1-MTS), protège les cellules d'un stress oxydatif, probablement en raison d'une efficacité accrue dans la réparation De 8-oxoG dans l'ADNmt. L'objectif principal de notre projet est d'élucider si la perte spécifique de l'activité de réparation 8-oxoG dans les mitochondries (mais pas dans le compartiment nucléaire) a un impact sur les fonctions organelles et / ou sur la viabilité cellulaire et aussi pour dévoiler le mécanisme / s Derrière les effets protecteurs d'OGG1 sur la physiologie mitochondriale et la maintenance d'ADNmtMitochondria are unique structures within the mammalian cell. These organelles carry their own genome (mitochondrial DNA, mtDNA) which consists of a small molecule that codifies for 13 polypeptides of the electron transport chain (ETC), 22 tRNA and 2 rRNA genes for its own protein synthesis. MtDNA is proposed to be more susceptible to oxidative stress than the nuclear genome (nDNA) because not only it lacks protective histones but also because of its proximity to ETC complexes which are the main ROS producers in mammalian cells. Among all the types of mtDNA damage, oxidative damage is the most prevalent and, by far, the best studied. Base excision repair (BER) pathway is an evolutionarily conserved DNA repair mechanism that repairs non-bulky DNA base damages. Since guanine has the lowest redox potential of any other bases in DNA, it is readily oxidized to 8-oxoguanine (8-oxoG) that is the most frequent alteration induced by ROS on both, nDNA and mtDNA. If the replication fork bypasses the 8-oxoG before its removal, an A is often inserted on the opposite DNA strand and subsequent replications fix the G to T transversion. When paired with cytosine, 8-oxoG is removed from DNA by the 8-oxoguanine DNA glycosylase (OGG1) that in such a way initiates the BER process. OGG1 is a bifunctional housekeeping glycosylase that, together with other various BER enzymes is present in both nuclear and mitochondrial compartments, highlighting the importance of maintaining mtDNA integrity for normal cellular functioning. It has been demonstrated that the overexpression of a recombinant version of OGG1, specifically targeted to mitochondria by an additional Mitochondrial Targeting Signal (MTS) (OGG1-MTS), protects the cells from an oxidative stress, likely due to an increased efficiency in the repair of 8-oxoG in mtDNA. The main goal of our project is to elucidate if the specific loss of 8-oxoG repair activity in mitochondria (but not in nuclear compartment) has an impact on the organelles’ functions and/or on cell viability and also to unveil the mechanism/s behind the protective effects of OGG1 on mitochondrial physiology and mtDNA maintenance
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Kaiser, Kevin Michael. "A simulation study of predictive maintenance policies and how they impact manufacturing systems". Thesis, University of Iowa, 2007. http://ir.uiowa.edu/etd/152.
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Dietz, Anthony, Eric Friets, William Finger, Jerry Bieszczad, Matt Miller e Lawrence Freudinger. "ONLINE DISTRIBUTED VEHICLE AND MACHINERY HEALTH MANAGEMENT". International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/605375.
Testo completoAbstract (sommario):
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, NevadaModern aircraft and space vehicles routinely sense and record vast quantities of information relevant to assessing the vehicles’ health. However, limitations imposed by the bandwidth of telemetry and network connections prevent real-time transmission of the complete data set to central stations for analysis. An online health-management system suitable for bandwidth-limited network environments that enables interrogation of the full data set by ground-based operators is described. The system uses distributed objects organized in a data processing hierarchy linked by a buffered data-management subsystem. Reduced health information is routinely transmitted, but dynamic reports may be requested on demand from any object.
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Emovon, Ikuobase. "Multi-criteria decision making support tools for maintenance of marine machinery systems". Thesis, University of Newcastle upon Tyne, 2016. http://hdl.handle.net/10443/3280.
Testo completoAbstract (sommario):
For ship systems to remain reliable and safe they must be effectively maintained through a sound maintenance management system. The three major elements of maintenance management systems are; risk assessment, maintenance strategy selection and maintenance task interval determination. The implementation of these elements will generally determine the level of ship system safety and reliability. Reliability Centred Maintenance (RCM) is one method that can be used to optimise maintenance management systems. However the tools used within the framework of the RCM methodology have limitations which may compromise the efficiency of RCM in achieving the desired results. This research presents the development of tools to support the RCM methodology and improve its effectiveness in marine maintenance system applications. Each of the three elements of the maintenance management system has been considered in turn. With regard to risk assessment, two Multi-Criteria Decision Making techniques (MCDM); Vlsekriterijumska Optimizacija Ikompromisno Resenje, meaning: Multi-criteria Optimization and Compromise Solution (VIKOR) and Compromise Programming (CP) have been integrated into Failure Mode and Effects Analysis (FMEA) along with a novel averaging technique which allows the use of incomplete or imprecise failure data. Three hybrid MCDM techniques have then been compared for maintenance strategy selection; an integrated Delphi-Analytical Hierarchy Process (AHP) methodology, an integrated Delphi-AHP-PROMETHEE (Preference Ranking Organisation METHod for Enrichment Evaluation) methodology and an integrated Delphi-AHP-TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) methodology. Maintenance task interval determination has been implemented using a MCDM framework integrating a delay time model to determine the optimum inspection interval and using the age replacement model for the scheduled replacement tasks. A case study based on a marine Diesel engine has been developed with input from experts in the field to demonstrate the effectiveness of the proposed methodologies.
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Yearby, Shedrick Dashun. "USMC Aviation Maintenance and Repair Cost for the H-1 Upgrade". Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/6891.
Testo completoAbstract (sommario):
MBA Professional ReportApproved for public release, distribution unlimited
This research focuses on the Marine Corps Aviation Maintenance and Repair Cost for the H-1 Upgrade platform. Onsite visits with the Program Manager Air 276 (PMA-276), the Naval Supply Weapons Systems Support (NAVSUP WSS), the Defense Logistics Agency (DLA), and Marine Aviation Logistics Squadron 39 (MALS-39) are conducted to obtain information regarding readiness costs and efficiencies that have impacted the total cost for a transitioning aircraft in Marine aviation. PMA-276, NAVSUP WSS, DLA, and MALS-39 make up the H-1 Cross-Functional Team (CFT). The H-1 CFT provides actionable metrics and best practices that focus on cost concerns (programmatic, material, management, and execution) from all levels of aviation logistics and planning. Key areas of improvement or replication are identified through metric-based solutions that affect cost reductions throughout the AH-1Z and UH-1Y integration.
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Wood, Thomas L. "Evaluation of project selection techniques for pavement network maintenance and repair". Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/25909.
Testo completoAbstract (sommario):
Different approaches have been suggested for determining the optimal
mix of repair projects for a pavement network. These methods range from
random selection to sophisticated mathematical optimization models.
This paper presents an analysis of several questions regarding the
effectiveness of three possible selection methods.
First, the performance of three separate single year project selection
methods on different size networks is assessed over a broad funding spectrum.
The results indicate that as funding levels increase, the benefit obtained by
different selection methods converge. In addition, as the size of the network
increases, the convergence tends to occur at progressively lower funding levels.
Second, the effect of the performance prediction models on these same
selection methods is assessed by altering the coefficients of the models to predict both faster and slower deterioration of the network. The "select sets" of
projects created by priority ranking selection and Knapsack IP selection at three
separate funding levels are compared to determine how much variation is introduced by the changes in the performance prediction. With a 30%
acceleration and deceleration of the deterioration curves, there was little change
in the optimal project set created by either method.
Finally, a modified Monte Carlo model is used to assess the general
shape of the solution space. The results suggest that the solution space is relatively flat except in the immediate vicinity of the optimum. This, in turn,
suggests that a Monte Carlo approach to this problem would require a large
number of trials to approximate the optimum. This finding conceptually supports
findings in this study and others, as well as the intuitive observation, that random
maintenance and repair strategies perform poorly compared to more rational
approaches. Since only a few sets of repair projects are near the optimum, the
chances of a random selection matching one of these near optimal project sets are relatively small.
45
Coxon, W. D. "Evaluation of models for decision making in inspection and repair maintenance". Master's thesis, University of Cape Town, 1987. http://hdl.handle.net/11427/21151.
Testo completoAbstract (sommario):
There has been growth in the costs of maintenance over the last 40 years. This can be linked directly to the changes in production technology over that period of time. However. there has also been growth in the field of management science and operations research. Many models have been developed to assist the maintenance function in its decisions. However. it would appear from engineering journals and shop floor practice that these models are not well used. For this research the method of inspection and repair maintenance has been chosen. Mainly because it is one of the most widely used methods. The objectives of the research are as follows: (1) To investigate the state of the art of plant and equipment maintenance paying particular attention to the inspection and repair policy. (2) To establish what basic models are available for decision making in inspection and repair maintenance. (3) To establish how feasible and useful each of these models is in the practical engineering environment. (4) To consider factors in the implementation of a decision making model in the inspection and repair policy with particular reference to the most practical and feasible model investigated.
46
Konda, Issa 1962. "Tractor repair and maintenance costs and management policies in Burkina Faso". Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/277842.
Testo completoAbstract (sommario):
Farm machinery management data were collected in Burkina Faso, for the prediction of repair and maintenance costs. Equations were developed to predict repair and maintenance costs of tractors, cane loaders, generators and motorpumps. The analysis of data revealed that tractor repair and maintenance appears a greater burden than predicted by the American and Australian data. Tractor trade-in was not prescribed by the rule of minimum total cost per unit tractor use. Farm machinery and power units were operated more than twice as long as in the United States. New machine purchase was discouraged by the current sugar prices on the local market.
47
Toledo, Maria Luiza Guerra de. "Determination of the optimal periodic maintenance policy under imperfect repair assumption". Universidade Federal de Minas Gerais, 2014. http://hdl.handle.net/1843/BUOS-9KRG8A.
Testo completoAbstract (sommario):
An appropriate maintenance policy is essential to reduce expenses and risks related to repairable systems failures. The usual assumptions of minimal or perfect repair at failures are not suitable for many real systems, requiring the application of Imperfect Repair models. In this work, the classes Arithmetic Reduction of Age and Arithmetic Reduction of Intensity, proposed by Doyen and Gaudoin (2004) are explored. Likelihood functions for such models are derived, and the parameters are estimated, allowing to compute reliability indicators to forecast the future behavior of the failure process. Under the classic Imperfect Repair virtual age model presented by Kijima et al. (1988) (particular case of Aithmetic Reduction of Age class), a periodic Preventive Maintenance policy is proposed, which estimates optimal time intervals for Preventive Maintenance, in order to minimize (preventive and corrective) maintenance costs. Under a dynamic perspective, it is showed how this policy can be improved, using each failure observation in order to recalculate the optimal time to Preventive Maintenance for a particular system, considering the effect of the repair action. These policies are applicable to any Imperfect Repair model. Monte Carlo simulation studies are implemented in order to evaluate the performance of the proposed methods. Those methods are applied to a real situation regarding the maintenance of engines of off-road trucks used in a mining company. These results bring valuable information to support decision making regarding Preventive Maintenance policy..
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Peterson, Reginald E. "Exploring Customers' Perceptions of Third Party Maintenance, Repair, and Operating Programs". ScholarWorks, 2016. https://scholarworks.waldenu.edu/dissertations/2170.
Testo completoAbstract (sommario):
A survey of 25 industrial manufacturing organizations in the U. S. indicated that 70% of respondents experienced dissatisfaction with their outsourcing programs due to unfulfilled expectations, which caused negative continuance intentions. The purpose of this descriptive case study was to explore the experiences of customers who currently use 3PMRO outsourcing programs to determine what factors affect satisfaction levels in the Southern United States. The conceptual framework for this study was the expectancy disconfirmation paradigm, which connects consumer satisfaction level to the fulfillment of consumer expectations. Data were collected from interviews of 22 procurement professionals of maintenance, repair, and operating supplies; observations of 3PMRO supplier performance meetings; and the analysis of performance scorecard documents. Data were analyzed using pattern matching followed by thematic analysis. Three themes were identified through the data analysis that affected consumer satisfaction: inventory management services, utilization of outsourced labor resources, and total cost value of the 3PMRO program. According to results, satisfaction of 3PMRO consumers are based on the proper utilization of a 3PMRO program for the intended limitations of the organization, reduced MRO supply costs, improved inventory management strategies, and improved competitive advantage from the realignment of resources to focus on core competencies. Implications for positive social change include increased awareness of cradle-to-grave inventory management to prevent improper disposal of non-biodegradable materials into our environment.
49
Barnhart, Cynthia. "Investigation of need for organized maintenance". Virtual Press, 1986. http://liblink.bsu.edu/uhtbin/catkey/450777.
Testo completoAbstract (sommario):
The benefits of maintenance have been known for centuries, and throughout history these benefits have been the basis for much discussion. Recently such benefits have been formally proposed in terms of scheduled or cyclical maintenance programs. These programs have been developed for important historic buildings; yet the same benefits can be applied to any house. This concept is the basis of this thesis.The thesis begins with a discussion of the obvious need for some maintenance program and describes the recent interest of local governments in some form of maintenance planning, discussing the benefits of an organized approach to maintenance. Next it briefly reviews the beginnings and history of maintenance theories and is followed by a discussion of maintenance as a level of conservation of building. Basic statistics about homeowners and the development of the survey are addressed, which leads to the presentation of compiled results of the survey and a interpretation of the data. The conclusion indicates a direction for the development of an organized maintenance plan.
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Swanson, Joel R. "An evaluation of employee exposures associated with aircraft paint stripping using methylene chloride at an aircraft maintenance facility". Online version, 1998. http://www.uwstout.edu/lib/thesis/1998/1998swansonj.pdf.
Testo completo