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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
511

Evaluation of model-based fault diagnosis combining physical insights and neural networks applied to an exhaust gas treatment system case study

Kleman, Björn, Lindgren, Henrik January 2021 (has links)
Fault diagnosis can be used to early detect faults in a technical system, which means that workshop service can be planned before a component is fully degraded. Fault diagnosis helps with avoiding downtime, accidents and can be used to reduce emissions for certain applications. Traditionally, however, diagnosis systems have been designed using ad hoc methods and a lot of system knowledge. Model-based diagnosis is a systematic way of designing diagnosis systems that is modular and offers high performance. A model-based diagnosis system can be designed by making use of mathematical models that are otherwise used for simulation and control applications. A downside of model-based diagnosis is the modeling effort needed when no accurate models are available, which can take a large amount of time. This has motivated the use of data-driven diagnosis. Data-driven methods do not require as much system knowledge and modeling effort though they require large amounts of data and data from faults that can be hard to gather. Hybrid fault diagnosis methods combining models and training data can take advantage of both approaches decreasing the amount of time needed for modeling and does not require data from faults. In this thesis work a combined data-driven and model-based fault diagnosis system has been developed and evaluated for the exhaust treatment system in a heavy-duty diesel engine truck. The diagnosis system combines physical insights and neural networks to detect and isolate faults for the exhaust treatment system. This diagnosis system is compared with another system developed during this thesis using only model-based methods. Experiments have been done by using data from a heavy-duty truck from Scania. The results show the effectiveness of both methods in an industrial setting. It is shown how model-based approaches can be used to improve diagnostic performance. The hybrid method is showed to be an efficient way of developing a diagnosis system. Some downsides are highlighted such as the performance of the system developed using data-driven and model-based methods depending on the quality of the training data. Future work regarding the modularity and transferability of the hybrid method can be done for further evaluation.
512

Prognostics for Condition Based Maintenance of Electrical Control Units Using On-Board Sensors and Machine Learning

Fredriksson, Gabriel January 2022 (has links)
In this thesis it has been studied how operational and workshop data can be used to improve the handling of field quality (FQ) issues for electronic units. This was done by analysing how failure rates can be predicted, how failure mechanisms can be detected and how data-based lifetime models could be developed. The work has been done on an electronic control unit (ECU) that has been subject to a field quality (FQ) issue, determining thermomechanical stress on the solder joints of the BGAs (Ball Grid Array) on the PCBAs (Printed circuit board assembly) to be the main cause of failure. The project is divided into two parts. Part one, "PCBA" where a laboratory study on the effects of thermomechanical cycling on solder joints for different electrical components of the PCBAs are investigated. The second part, "ECU" is the main part of the project investigating data-driven solutions using operational and workshop history data. The results from part one show that the Weibull distribution commonly used to predict lifetimes of electrical components, work well to describe the laboratory results but also that non parametric methods such as kernel distribution can give good results. In part two when Weibull together with Gamma and Normal distributions were tested on the real ECU (electronic control unit) data, it is shown that none of them describe the data well. However, when random forest is used to develop data-based models most of the ECU lifetimes of a separate test dataset can be correctly predicted within a half a year margin. Further using random survival forest it was possible to produce a model with just 0.06 in (OOB) prediction error. This shows that machine learning methods could potentially be used in the purpose of condition based maintenance for ECUs.
513

Skladovací hala č. 2 v Rousínově - stavebně technologický projekt / Storage hall No. 2 in Rousínov - construction-technological project

Gottvaldová, Denisa Unknown Date (has links)
The subject of my diploma thesis is a construction-technological solution for realization of a storage hall in Rousínov. The work deals with a time and financial plan for all buildings of the project Storage Hall, Rousínov. A technical report, a study of the implementation of the construction’s individual stages, a design and assessment of transport routes, a design of the construction site equipment and a design of the machinery were prepared for the building No. 2. An itemized budget with a statement of acreage and construction schedule was prepared. A technological regulation and a control and test plan were prepared for the implementation process of the wire-reinforced concrete industrial floor. Within the diploma thesis, a technological regulation for the implementation of a reinforced concrete retaining wall was prepared. Noise pollution caused by the construction site was examined and evaluated in a noise study. The environmental requirements for the storage hall building No. 2 were processed.
514

Energy Prediction in Heavy Duty Long Haul Trucks

Khuntia, Satvik 22 December 2022 (has links)
No description available.
515

[pt] AVALIAÇÃO METROLÓGICA EM OPERAÇÕES DE TRANSFERÊNCIAS DE CUSTÓDIA DE GLP / [en] METROLOGICAL EVALUATION IN LPG CUSTODY TRANSFER OPERATIONS

PEDRO LINCOLN DE SOUZA FILHO 10 January 2022 (has links)
[pt] Esta dissertação visa a aplicar uma metodologia para avaliar as diferenças máximas permissíveis nas operações de transferência de custódia de GLP para cada operação em particular, utilizando testes de hipóteses baseados na incerteza de medição, em contraponto à utilização de valores pré-estabelecidos em normas e regulamentos técnicos metrológicos. Tais documentos propõem um valor único de incerteza máximas nas medições de transferência de custódia, sem estabelecer diferenças máximas permissíveis nas operações entre dois sistemas, cabendo aos fornecedores e clientes negociar este parâmetro, o que frequentemente causa disputas. Os resultados mostraram que, em um sistema isolado, ao contrário de outros métodos, as condições ambientais não influenciam o método de medição de massa e sua incerteza. Nenhuma diferença máxima permissível de massa transferida de GLP entre caminhões-tanque e estações de medição excede 1,0 porcento; em contraste, quando uma esfera de armazenamento é parte de um dos sistemas de medição, este parâmetro depende completamente das condições operacionais e definitivamente um valor único não deve ser considerado. / [en] This dissertation aims to apply a methodology to assess the maximum allowable differences in LPG custody transfer operations for each particular operation, using hypothesis tests based on measurement uncertainty, as opposed to using pre-established values in metrological standards and technical regulations. Such documents propose a single value for maximum uncertainty in custody transfer measurements, without establishing maximum permissible differences in operations between two systems, leaving it up to suppliers and customers to negotiate this parameter, which often causes disputes. The results showed that in an isolated system, unlike other methods, environmental conditions do not influence the mass measurement method and its uncertainty. No maximum permissible difference of transferred mass of LPG between tank trucks and measuring stations exceeds 1.0 percent; in contrast, when a storage sphere is part of one of the measuring systems, this parameter completely depends on the operating conditions and definitely a single value should not be considered.
516

Utveckling av luftkompressormonterad ljuddämpare / Development of an air compressor mounted silencer

Mustafa, Kobin, Rozumberski, Kristian January 2018 (has links)
Ett ljudfenomen som uppstår i samband med luftkomprimeringen i den nya D7 motorn har uppmärksammats som ett problem av kunderna. Ljudfenomenet som resonerar i hytten bidrar till en obehaglig arbetsmiljö. Uppdraget har i sin tur varit att utveckla en luftkompressormonterad ljuddämpare mot en kravspecifikation som eliminerar detta fenomen. Med hjälp av diverse verktyg och en spiral produktutvecklingsprocess utfördes ett flertal iterationer av dem koncept som kan tänkas lösa problemet. Dessa iterationer konstruerades i mjukvaran CATIA V5 för att sedan beställas in som fysiska prototyper i materialet Pa12. För att bekräfta prototypernas funktionalitet utfördes simuleringar samt fysiska tester. Det resulterande arbetet blev ett konceptförslag till Scania CV AB som uppfyller kravspecifikationerna. Lösningens ljuddämpningsförmågan reducerade ljudfenomenet med 73% i genomsnitt. Med hjälp av observationer och analyser under de fysiska testgenomförandet uppmärksammades komplikationer som bör åtgärdas. Det mest kritiska med det nuvarande konceptet är dem vibrationer som uppstår. För att åtgärda detta problem kommer det krävas ytterligare infästningspunkter på motsvarande sida till de nuvarande. All mätdata i denna rapport är modifierat. Detta för att skydda känslig information. / A noise phenomenon that arises in connection with air compression in the new D7 engine has been noted as a problem by the customers. The sound phenomenon resonates in the cabin contributes to an unpleasant work environment. The mission, in turn, has been to develop an air compressor-mounted silencer against a requirement specification to eliminate this phenomenon. Using various tools and a spiral product development process, a number of iterations were made of those concepts that could solve the problem. These iterations were engineered in the CATIA V5 software, then ordered as physical prototypes in the material Pa12. To confirm the prototypes' functionality, simulations and physical tests were performed. The resulting work became a concept proposal for Scania CV AB that meets the requirements specifications. The solution managed to reduce the sound phenomenon by 73% on average. With the help of observations and analyzes during the physical test implementation, complications were noted that should be addressed. The most critical on the current concept is the vibration that occurs. To fix this problem additional attachment points will be required on the corresponding side to the current ones. All data in this report have been modified. This is to protect sensitive information.
517

Affärsmodellspåverkan vid införande av HCT i Sverige : Implikationer för fordonstillverkare vid förändrade villkor för styckegodstransporter / Business model implications of HCT introduction in Sweden

Tham, Henrik, Mogard, Caroline January 2014 (has links)
Syfte – Studiens syfte är att öka kunskapen om hur fordonstillverkares affärsmodeller påverkas vid förändring av statliga regelverk genom att studera ett framtida införande av HCT i Sverige. HCT, High Capacity Transports, är ett samlingsnamn för lastbilar som är tyngre och/eller längre än vad gällande lagstiftning tillåter. Regelförändringen övervägs för att sänka kostnader och miljöpåverkan.  Metod – Arbetet har genomförts i form av en case-studie. För att studera påverkan på både fordonstillverkares och åkeriers affärsmodeller har intervjuer genomförts med varuägare, åkerier och förare inom fjärrtransporter av styckegods. Detta har kompletterats med löpande kontakt med uppdragsgivande fordonstillverkare samt deltagande i konferenser inom ramen för det nationella HCT-arbetet.  Resultat – Inget större modalskifte mellan järnvägs- och landsvägstransporter förväntas eftersom järnvägens infrastruktur styr transportvalet och inte påverkas av ett HCT-tillåtande. Vidare riskerar fordonstillverkare att sälja färre lastbilar vid ett tillåtande av HCT men genom anpassning av affärsmodellen kan de öka värdet per fordon. Detta värde kan ökas genom att sänka kundernas driftkostnad, maximera fordonens drifttid och föra kundens talan mot myndigheter.  Praktiskt bidrag – Studien har resulterat i ett nytt affärsmodellsramverk för fordonstillverkare vid införande av HCT. Ramverket visar att samtliga nuvarande värdeområden bör inkluderas i kommande affärsmodell och att flertalet får ökad betydelse. På grund av nya förutsättningar blir vissa av dessa områden dessutom svårare att uppnå samtidigt som nya områden kan läggas till.  Vetenskapligt bidrag – Genom att öka kunskapen om affärsmodellspåverkan vid förändring av statliga regelverk utvidgar studien befintlig teori om förändringar av affärsmodeller. Studien belyser även vikten av att studera hela leverantörskedjan vid sådana förändringar. Detta eftersom statliga regelverk styr förutsättningarna för flera aktörer med starka inbördes relationer. Därmed sprider sig effekterna av en regelverksförändring till övriga aktörer i kedjan. / Purpose – The purpose of this study is to increase the knowledge about how legislative changes affect the business model of vehicle manufactures by studying a future allowance of HCT in Sweden. HCT, High Capacity Transports, is a generic term for trucks exceeding today’s weight and/or length regulations. Reasons for implementing HCT include reducing costs and environmental consequences. Method – Effects of legislative changes have been studied through a case-study of how HCT would affect the Swedish transport system. In order to study business model implications for both vehicle manufactures and hauliers, interviews have been held with transport buyers, hauliers and drivers within long distance haulage of break bulk cargo. This has been complemented by continuous contact with the commissioning vehicle manufacturer and participation in HCT conferences. Findings – Findings indicate that there will be no major modal shift between railway and road since the railway infrastructure determines the modal choice and is unaffected by HCT. Furthermore findings show that vehicle manufactures risk to sell fewer vehicles in case of HCT allowance but a business model adaption can increase the value per vehicle. This can be achieved by reducing customer operating costs, increasing vehicle uptime and being the voice of the customer against authorities. Practical implications – The study has resulted in a HCT business model framework for vehicle manufactures. The framework shows that all present value areas should be included in a future business model and that several areas will increase in importance. In the effect of new conditions several areas will become more difficult to fulfill. Furthermore new areas will be added. Theoretical implications – This study expands current theories within business model changes by increasing knowledge about how legislative changes affect business models. Furthermore this study highlights the importance of studying the whole supply chain in the event of these changes. The reason for this is that legislations affect the conditions for several players with strong peer relationships. Thereby effects due to changed legislations will spread to other players in the chain.
518

Pallar och lastbärare i Försvarsmakten : Ett tvådimensionellt stuvningsproblem av fyllnadsgraden för pallar på rullflak, lastbilsflak, lastbilssläp och i containrar / Pallets and cargo carriers in the Swedish Armed Forces : A two dimensional stowage problem concerning the space efficiency of pallets on cargo carriers of the Swedish Armed Forces

Sjöberg, Johan January 2024 (has links)
Förnödenheter transporteras i Försvarsmakten på ett stort antal olika pallar med flertalet olikal astbärare. Rapporten svarar på frågorna: Vilken är den mest optimala lastpallen för försvarsmakten sett till tvådimensionell fyllnadsgrad? Går det med enkla medel att öka den tvådimensionella fyllnadsgraden, på rapportens valda lastbärare, genom att välja en väletablerad standardpall? Lastbärarna som rapporten avhandlar är container, rullflak, lastbilsflak och lastbilssläp. Rapporten använder pallens och fyra lastbärares lastyta för att utifrån sju stuvningssätt beräkna det antalet pallar som får plats på respektive lastbärare utifrån samtliga stuvningssätt. Därefter har den maximala fyllnadsgraden av respektive pall på respektive lastbärare tagits fram och presenterats. Fyllnadsgraden som avses är den nyttjade lastytan och rapporten avhandlar endast ett tvådimensionellt lastproblem. Rapportens optimala pall vore 1165x830mm2 stor och uppnår en genomsnittlig fyllnadsgrad på 96%, pallen har tagits fram genom simuleringar baserat på beräkningar. Den tangerar eller överträffar fyllnadsgraden för standardpallar såsom Europapallen (1200x800mm2) och Natopallen(1200x1000mm2) på samtliga lastbärare. Natopallen har högre genomsnittlig fyllnadsgrad, 90%, jämfört med Europapallen på 84%. Natopallen har en jämn fyllnadsgrad medan Europapallen är väldigt effektiv på lastbil med släp. / In the Swedish Armed Forces supplies are transported using a large number of different pallets on a number of different cargo carriers. This report answers the questions: Which is the most space efficient pallet size regarding two dimensional stowage? Is it possible to increase the two dimensional space efficiency, on selected cargo carriers, by transitioning to a well established standard pallet? The report is based on the size of both the cargo carriers and pallets. Seven stowage methods are used to calculate the number of each pallet which can fit on each of the four cargo carrier for each stowage method. Following this the maximum space efficiency of each pallet on all the cargo carriers are calculated. The most space efficient pallet size is 1165x830mm2, a pallet size which has been simulated using the calculations of this report. The pallet has an average space efficiency of 96% which is as high or higher compared to the European pallet (1200x800mm2) or NATO pallet (1200x1000mm2) on the selected cargo carriers. The NATO pallet has an average space efficiency of 90% compared to 84% using the European pallet. The NATO pallet has an even space efficiency on the selected cargo carriers compared to the European pallet which is highly space efficient on trucks with trailers.
519

Response of concrete pavements under moving vehicular loads and environmental effects

Darestani, Mostafa Yousefi January 2007 (has links)
The need for modern transportation systems together with the high demand for sustainable pavements under applied loads have led to a great deal of research on concrete pavements worldwide. Development of finite element techniques enabled researchers to analyse the concrete pavement under a combination of axle group loadings and environmental effects. Consequently, mechanistic approaches for designing of concrete pavements were developed based on results of finite element analyses. However, unpredictable failure modes of concrete pavements associated with expensive maintenance and rehabilitation costs have led to the use of empiricalmechanistic approach in concrete pavement design. Despite progressive knowledge of concrete pavement behaviour under applied loads, concrete pavements still suffer from deterioration due to crack initiation and propagation, indicating the need for further research. Cracks can be related to fatigue of the concrete and/or erosion of materials in sub-layers. Although longitudinal, midedge and corner cracks are the most common damage modes in concrete pavements, Austroads method for concrete pavement design was developed based on traditional mid-edge bottom-up transverse cracking introduced by Packard and Tayabji (1985). Research presented in this thesis aims to address the most common fatigue related distresses in concrete pavements. It uses comprehensive finite element models and analyses to determine the structural behaviour of concrete pavements under vehicular loads and environmental effects. Results of this research are supported by laboratory tests and an experimental field test. Results of this research indicate that the induced tensile stresses within the concrete pavement are significantly affected by vehicle speed, differential temperature gradient and loss of moisture content. Subsequently, the interaction between the above mentioned factors and concrete damage modes are discussed. Typical dynamic amplifications of different axle groups are presented. A new fatigue test setup is also developed to take into consideration effects of pavement curvature on fatigue life of the concrete. Ultimately, results of the research presented in this thesis are employed to develop a new guide for designing concrete pavements with zero maintenance of fatigue damage.
520

Vybrané části stavebně technologického projektu psychiatrické kliniky Fakultní nemocnice Brno / Selected Parts of the Construction Technology Project of the Psychiatric Clinic of the University Hospital Brno

Drozd, Michal January 2020 (has links)
The subject of my diploma thesis are selected parts of the construction technology project of the psychiatric clinic of the University Hospital Brno based on the provided project documentation. It is an extension of a new six-storey building to the existing buildings. The thesis contains a technical report to the construction technology project, the coordination situation of the construction, the situation of wider transport routes, time and financial plan by objects, study of the realization of the main technological stages, a site equipment design, a design of a machine set, technological regulation for monolithic structures, quality control and testing plan of monolithic structures, noise study and selected documents for LEED certification.

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