Search

Road transport accounts for nearly a fifth of the global greenhouse gas emissions. Despite significant reductions, achieved by e.g. the introduction of electric vehicles, more can be done. One way is to reduce the rolling resistance, which is one of the resistive forces acting on a moving vehicle. The overall goal of this work is to fill part of the knowledge gap regarding tyre rolling resistance to support the development of more energy efficient vehicles. Focus is on the influence of the operating conditions, with emphasis on tyre temperature and non-steady-state measurements. Today, rolling resistance of new tyres is rated to guide consumers to choose an energy-efficient tyre. However, this rating is based on standardised steady-state drum measurements at 25°C which often results in the measured rolling resistance being evaluated at higher operating temperature than during normal driving. To account for the drum’s curvature, Clark’s formula is used to convert the drum measurement to represent the tyre’s rolling resistance on a flat surface. In this work, a new method for non-steady-state rolling resistance measurements on a flat surface has been developed and used to show that rolling resistance has a large and non-linear dependence on tyre temperature. This influence varied across the tested tyres, which indicates that the rolling resistance rating could be affected by the measurement temperature. It was shown that the influence of the tyre temperature on rolling resistance was more profound on a drum compared to a flat track. Therefore, it would be beneficial to include a temperature dependency in Clark’s formula to increase its accuracy. Furthermore, a rolling resistance model has been developed to describe the relationship between tyre deformation and rolling resistance. The model is parametrised with measurement data and simple enough to be used in complete vehicle dynamic simulations. Overall, this work has contributed with an increase of knowledge about ro, Vägtransporter står för nästan en femtedel av de globala utsläppen av växthusgaser. En stor minskning har åstadkommits genom bl.a. introduktionen av elektriska fordon, men det räcker inte. Ett sätt är att minska rullmotståndet, som är en del av det färdmotstånd som verkar på ett fordon i rörelse. Det övergripande målet för den här avhandlingen är att fylla en del av kunskapsluckan om rullmotstånd för att bidra till utvecklingen av mer energieffektiva fordon. Fokus ligger på driftsvillkorens påverkan, framförallt däcktemperatur och icke-steady-state. Idag klassificeras däcks rullmotstånd för att hjälpa konsumenter att välja energieffektiva däck. Klassificeringen baseras dock på en standardiserad trumprovning under steady-state i 25°C, vilket ofta ger betydligt högre däcktemperatur än vid verkliga körförhållanden. För att ta hänsyn till trummans kurvatur används Clarks formel för att omvandla trummätningen till ett motsvarande rullmotstånd på en plan yta. I detta arbete presenteras en ny metod för rullmotståndsmätningar vid icke-steady-state på plant underlag, vilken har utvecklats och använts för att påvisa att rullmotstånd har ett starkt och olinjärt beroende av däcktemperaturen. Däcktemperaturens inverkan på rullmotståndet varierade mellan de provade däcken, vilket indikerar att rullmotståndsklassificeringen kan påverkas av mättemperaturen. Vidare visades att däcktemperaturens påverkan på rullmotståndet är större på trumma jämfört med plant underlag. Därmed skulle det vara fördelaktigt att inkludera ett temperaturberoende i Clarks formel för att öka dess noggrannhet. Vidare har en rullmotståndsmodell utvecklats som beskriver sambandet mellan rullmotstånd och däckdeformation. Modellen är parametriserad med mätdata och tillräckligt enkel för att användas i fordonsdynamiska simuleringar av ett komplett fordon. Sammantaget har detta arbete bidragit med ökad kunskap om rullmotstånd och däcktemperaturens påverkan, genom utvecklande och användning av en ny mätmetod. Resu

Road transport accounts for nearly a fifth of the global greenhouse gas emissions. Despite significant reductions, achieved by e.g. the introduction of electric vehicles, more can be done. One way is to reduce the rolling resistance, which is one of the resistive forces acting on a moving vehicle. The overall goal of this work is to fill part of the knowledge gap regarding tyre rolling resistance to support the development of more energy efficient vehicles. Focus is on the influence of the operating conditions, with emphasis on tyre temperature and non-steady-state measurements. Today, rolling resistance of new tyres is rated to guide consumers to choose an energy-efficient tyre. However, this rating is based on standardised steady-state drum measurements at 25°C which often results in the measured rolling resistance being evaluated at higher operating temperature than during normal driving. To account for the drum’s curvature, Clark’s formula is used to convert the drum measurement to represent the tyre’s rolling resistance on a flat surface. In this work, a new method for non-steady-state rolling resistance measurements on a flat surface has been developed and used to show that rolling resistance has a large and non-linear dependence on tyre temperature. This influence varied across the tested tyres, which indicates that the rolling resistance rating could be affected by the measurement temperature. It was shown that the influence of the tyre temperature on rolling resistance was more profound on a drum compared to a flat track. Therefore, it would be beneficial to include a temperature dependency in Clark’s formula to increase its accuracy. Furthermore, a rolling resistance model has been developed to describe the relationship between tyre deformation and rolling resistance. The model is parametrised with measurement data and simple enough to be used in complete vehicle dynamic simulations. Overall, this work has contributed with an increase of knowledge about ro, Vägtransporter står för nästan en femtedel av de globala utsläppen av växthusgaser. En stor minskning har åstadkommits genom bl.a. introduktionen av elektriska fordon, men det räcker inte. Ett sätt är att minska rullmotståndet, som är en del av det färdmotstånd som verkar på ett fordon i rörelse. Det övergripande målet för den här avhandlingen är att fylla en del av kunskapsluckan om rullmotstånd för att bidra till utvecklingen av mer energieffektiva fordon. Fokus ligger på driftsvillkorens påverkan, framförallt däcktemperatur och icke-steady-state. Idag klassificeras däcks rullmotstånd för att hjälpa konsumenter att välja energieffektiva däck. Klassificeringen baseras dock på en standardiserad trumprovning under steady-state i 25°C, vilket ofta ger betydligt högre däcktemperatur än vid verkliga körförhållanden. För att ta hänsyn till trummans kurvatur används Clarks formel för att omvandla trummätningen till ett motsvarande rullmotstånd på en plan yta. I detta arbete presenteras en ny metod för rullmotståndsmätningar vid icke-steady-state på plant underlag, vilken har utvecklats och använts för att påvisa att rullmotstånd har ett starkt och olinjärt beroende av däcktemperaturen. Däcktemperaturens inverkan på rullmotståndet varierade mellan de provade däcken, vilket indikerar att rullmotståndsklassificeringen kan påverkas av mättemperaturen. Vidare visades att däcktemperaturens påverkan på rullmotståndet är större på trumma jämfört med plant underlag. Därmed skulle det vara fördelaktigt att inkludera ett temperaturberoende i Clarks formel för att öka dess noggrannhet. Vidare har en rullmotståndsmodell utvecklats som beskriver sambandet mellan rullmotstånd och däckdeformation. Modellen är parametriserad med mätdata och tillräckligt enkel för att användas i fordonsdynamiska simuleringar av ett komplett fordon. Sammantaget har detta arbete bidragit med ökad kunskap om rullmotstånd och däcktemperaturens påverkan, genom utvecklande och användning av en ny mätmetod. Resu

Road transport accounts for nearly a fifth of the global greenhouse gas emissions. Despite significant reductions, achieved by e.g. the introduction of electric vehicles, more can be done. One way is to reduce the rolling resistance, which is one of the resistive forces acting on a moving vehicle. The overall goal of this work is to fill part of the knowledge gap regarding tyre rolling resistance to support the development of more energy efficient vehicles. Focus is on the influence of the operating conditions, with emphasis on tyre temperature and non-steady-state measurements. Today, rolling resistance of new tyres is rated to guide consumers to choose an energy-efficient tyre. However, this rating is based on standardised steady-state drum measurements at 25°C which often results in the measured rolling resistance being evaluated at higher operating temperature than during normal driving. To account for the drum’s curvature, Clark’s formula is used to convert the drum measurement to represent the tyre’s rolling resistance on a flat surface. In this work, a new method for non-steady-state rolling resistance measurements on a flat surface has been developed and used to show that rolling resistance has a large and non-linear dependence on tyre temperature. This influence varied across the tested tyres, which indicates that the rolling resistance rating could be affected by the measurement temperature. It was shown that the influence of the tyre temperature on rolling resistance was more profound on a drum compared to a flat track. Therefore, it would be beneficial to include a temperature dependency in Clark’s formula to increase its accuracy. Furthermore, a rolling resistance model has been developed to describe the relationship between tyre deformation and rolling resistance. The model is parametrised with measurement data and simple enough to be used in complete vehicle dynamic simulations. Overall, this work has contributed with an increase of knowledge about ro, Vägtransporter står för nästan en femtedel av de globala utsläppen av växthusgaser. En stor minskning har åstadkommits genom bl.a. introduktionen av elektriska fordon, men det räcker inte. Ett sätt är att minska rullmotståndet, som är en del av det färdmotstånd som verkar på ett fordon i rörelse. Det övergripande målet för den här avhandlingen är att fylla en del av kunskapsluckan om rullmotstånd för att bidra till utvecklingen av mer energieffektiva fordon. Fokus ligger på driftsvillkorens påverkan, framförallt däcktemperatur och icke-steady-state. Idag klassificeras däcks rullmotstånd för att hjälpa konsumenter att välja energieffektiva däck. Klassificeringen baseras dock på en standardiserad trumprovning under steady-state i 25°C, vilket ofta ger betydligt högre däcktemperatur än vid verkliga körförhållanden. För att ta hänsyn till trummans kurvatur används Clarks formel för att omvandla trummätningen till ett motsvarande rullmotstånd på en plan yta. I detta arbete presenteras en ny metod för rullmotståndsmätningar vid icke-steady-state på plant underlag, vilken har utvecklats och använts för att påvisa att rullmotstånd har ett starkt och olinjärt beroende av däcktemperaturen. Däcktemperaturens inverkan på rullmotståndet varierade mellan de provade däcken, vilket indikerar att rullmotståndsklassificeringen kan påverkas av mättemperaturen. Vidare visades att däcktemperaturens påverkan på rullmotståndet är större på trumma jämfört med plant underlag. Därmed skulle det vara fördelaktigt att inkludera ett temperaturberoende i Clarks formel för att öka dess noggrannhet. Vidare har en rullmotståndsmodell utvecklats som beskriver sambandet mellan rullmotstånd och däckdeformation. Modellen är parametriserad med mätdata och tillräckligt enkel för att användas i fordonsdynamiska simuleringar av ett komplett fordon. Sammantaget har detta arbete bidragit med ökad kunskap om rullmotstånd och däcktemperaturens påverkan, genom utvecklande och användning av en ny mätmetod. Resu

Road transport accounts for nearly a fifth of the global greenhouse gas emissions. Despite significant reductions, achieved by e.g. the introduction of electric vehicles, more can be done. One way is to reduce the rolling resistance, which is one of the resistive forces acting on a moving vehicle. The overall goal of this work is to fill part of the knowledge gap regarding tyre rolling resistance to support the development of more energy efficient vehicles. Focus is on the influence of the operating conditions, with emphasis on tyre temperature and non-steady-state measurements. Today, rolling resistance of new tyres is rated to guide consumers to choose an energy-efficient tyre. However, this rating is based on standardised steady-state drum measurements at 25°C which often results in the measured rolling resistance being evaluated at higher operating temperature than during normal driving. To account for the drum’s curvature, Clark’s formula is used to convert the drum measurement to represent the tyre’s rolling resistance on a flat surface. In this work, a new method for non-steady-state rolling resistance measurements on a flat surface has been developed and used to show that rolling resistance has a large and non-linear dependence on tyre temperature. This influence varied across the tested tyres, which indicates that the rolling resistance rating could be affected by the measurement temperature. It was shown that the influence of the tyre temperature on rolling resistance was more profound on a drum compared to a flat track. Therefore, it would be beneficial to include a temperature dependency in Clark’s formula to increase its accuracy. Furthermore, a rolling resistance model has been developed to describe the relationship between tyre deformation and rolling resistance. The model is parametrised with measurement data and simple enough to be used in complete vehicle dynamic simulations. Overall, this work has contributed with an increase of knowledge about ro, Vägtransporter står för nästan en femtedel av de globala utsläppen av växthusgaser. En stor minskning har åstadkommits genom bl.a. introduktionen av elektriska fordon, men det räcker inte. Ett sätt är att minska rullmotståndet, som är en del av det färdmotstånd som verkar på ett fordon i rörelse. Det övergripande målet för den här avhandlingen är att fylla en del av kunskapsluckan om rullmotstånd för att bidra till utvecklingen av mer energieffektiva fordon. Fokus ligger på driftsvillkorens påverkan, framförallt däcktemperatur och icke-steady-state. Idag klassificeras däcks rullmotstånd för att hjälpa konsumenter att välja energieffektiva däck. Klassificeringen baseras dock på en standardiserad trumprovning under steady-state i 25°C, vilket ofta ger betydligt högre däcktemperatur än vid verkliga körförhållanden. För att ta hänsyn till trummans kurvatur används Clarks formel för att omvandla trummätningen till ett motsvarande rullmotstånd på en plan yta. I detta arbete presenteras en ny metod för rullmotståndsmätningar vid icke-steady-state på plant underlag, vilken har utvecklats och använts för att påvisa att rullmotstånd har ett starkt och olinjärt beroende av däcktemperaturen. Däcktemperaturens inverkan på rullmotståndet varierade mellan de provade däcken, vilket indikerar att rullmotståndsklassificeringen kan påverkas av mättemperaturen. Vidare visades att däcktemperaturens påverkan på rullmotståndet är större på trumma jämfört med plant underlag. Därmed skulle det vara fördelaktigt att inkludera ett temperaturberoende i Clarks formel för att öka dess noggrannhet. Vidare har en rullmotståndsmodell utvecklats som beskriver sambandet mellan rullmotstånd och däckdeformation. Modellen är parametriserad med mätdata och tillräckligt enkel för att användas i fordonsdynamiska simuleringar av ett komplett fordon. Sammantaget har detta arbete bidragit med ökad kunskap om rullmotstånd och däcktemperaturens påverkan, genom utvecklande och användning av en ny mätmetod. Resu

In this work, the basic criteria of the process of the pantograph and overhead line interaction of railway rolling stock are considered. An analysis of the causes and consequences of impaired current collection was also performed. The analysis of existing systems and technical means for determining the qualitative and quantitative indicators of the pantograph and overhead line interaction was carried out and their classification was carried out according to the location, the principle of obtaining information and controlled parameters. Based on the results of research, the main quantitative and qualitative indicators of the interaction of current collectors with the overhead line in the conditions of operation on the railways of Ukraine, which should be subject to control, have been established. Field tests were also conducted to determine such indicators in real operating conditions of railway rolling stock. According to the results of the research, an experimental complex was developed to determine the indicators of the interaction of current receivers of various types of rolling stock with the contact network in operating conditions.

This thesis work was conducted at Luleå University of Technology in collaboration with Sandvik Rock Tools. The aim of the work was to determine the influence of carbon content on the wear performance in carburized steel in the dry contact interface of threaded connections between drill rods. In order to investigate this, samples of drill rod steel were carburized to three different carbon concentrations and shot peened to replicate the production process of a drill rod. The samples were wear tested by utilizing a twin-disc wear tester with one disc rotating at 100 RPM and the other at 3000 RPM to mimic the operating conditions in the threaded connection between drill rods. The results was evaluated by wear rate, surface topography, hardness as well as optical analysis by light optical microscopy and scanning electron microscopy. The results show that an increased surface carbon content provide a decrease in wear rate and an increase in hardness in the surface layer that undergo microstructural changes due to the frictional heat and contact pressure during wear testing. The primary wear mechanisms were identified as plastic deformation, adhesive scratching and material removal through delamination.

This thesis work was conducted at Luleå University of Technology in collaboration with Sandvik Rock Tools. The aim of the work was to determine the influence of carbon content on the wear performance in carburized steel in the dry contact interface of threaded connections between drill rods. In order to investigate this, samples of drill rod steel were carburized to three different carbon concentrations and shot peened to replicate the production process of a drill rod. The samples were wear tested by utilizing a twin-disc wear tester with one disc rotating at 100 RPM and the other at 3000 RPM to mimic the operating conditions in the threaded connection between drill rods. The results was evaluated by wear rate, surface topography, hardness as well as optical analysis by light optical microscopy and scanning electron microscopy. The results show that an increased surface carbon content provide a decrease in wear rate and an increase in hardness in the surface layer that undergo microstructural changes due to the frictional heat and contact pressure during wear testing. The primary wear mechanisms were identified as plastic deformation, adhesive scratching and material removal through delamination.

In this study, a comprehensive set of experimental tests were carried out to investigate individual cell voltage and temperature deviation under different operating conditions in a fuel cell stack. Five key operating conditions were considered: temperature, pressure, anode and cathode relative humidity, and cathode stoichiometry. Different configurations of reactant flow within the stack were also investigated. A 100 cm2 7-cell stack was used for the experiments, and voltage and temperature measurements were taken for each individual cell. Both ANOVA and range analysis method were used to evaluate the results. The findings showed that the performance of the external cells was consistently lower than that of the central ones since its temperature, the parameter that most affected performance, was also lower due to heat losses. Additionally, voltage deviation increased with temperature deviation. The study also revealed that stack performance was improved by an increase in temperature, pressure and cathode stoichiometry, whereas the effect of anode and cathode humidity was not so significant in the studied range. Furthermore, gravity played a clear role in water management, hindering the removal of condensed water for flow configurations where reactant gases were fed from the bottom interfaces of the stack.

In this work, the basic criteria of the process of the pantograph and overhead line interaction of railway rolling stock are considered. An analysis of the causes and consequences of impaired current collection was also performed. The analysis of existing systems and technical means for determining the qualitative and quantitative indicators of the pantograph and overhead line interaction was carried out and their classification was carried out according to the location, the principle of obtaining information and controlled parameters. Based on the results of research, the main quantitative and qualitative indicators of the interaction of current collectors with the overhead line in the conditions of operation on the railways of Ukraine, which should be subject to control, have been established. Field tests were also conducted to determine such indicators in real operating conditions of railway rolling stock. According to the results of the research, an experimental complex was developed to determine the indicators of the interaction of current receivers of various types of rolling stock with the contact network in operating conditions.

In this study, a comprehensive set of experimental tests were carried out to investigate individual cell voltage and temperature deviation under different operating conditions in a fuel cell stack. Five key operating conditions were considered: temperature, pressure, anode and cathode relative humidity, and cathode stoichiometry. Different configurations of reactant flow within the stack were also investigated. A 100 cm2 7-cell stack was used for the experiments, and voltage and temperature measurements were taken for each individual cell. Both ANOVA and range analysis method were used to evaluate the results. The findings showed that the performance of the external cells was consistently lower than that of the central ones since its temperature, the parameter that most affected performance, was also lower due to heat losses. Additionally, voltage deviation increased with temperature deviation. The study also revealed that stack performance was improved by an increase in temperature, pressure and cathode stoichiometry, whereas the effect of anode and cathode humidity was not so significant in the studied range. Furthermore, gravity played a clear role in water management, hindering the removal of condensed water for flow configurations where reactant gases were fed from the bottom interfaces of the stack.

Fossil fuel depletion, global warming, climate change, and steep hikes in the price of fuel are driving scientists to investigate commercial and environmentally friendly energy carriers like hydrogen. Steam methane reforming (SMR), a current commercial route for H2 production, has been considered the best remedy to fulfill the requirements. Despite the remarkable quantity of H2 produced by the SMR, this technology still faces major challenges such as catalyst deactivation due to the sintering of metal nanoparticles, coking, and generation of a large quantity of CO2. Firstly, the effects of catalyst types, kinetic models, and operating conditions on high-yield H2 production, the evolution path from gray to blue, via the conventional SMR are comprehensively reviewed. Secondly, exploiting intensified techniques such as membrane technology, sorption, fluidization, and chemical looping for SMR to blue H2 are discussed in detail. Further, a novel and sustainable path for the SMR process, hybridizing the use of novel materials and emerging technologies to produce turquoise H2, is proposed. Finally, the critical points for steam reforming process technology that can help leverage environmental, social, and governance (ESG) profiling have been discussed.

For heavy vehicle systems, within the power transmission chain from the driving machine to the working components (wheels), gears have a large share of application in the form of gearboxes, differentials and speed reducers. Their purpose is to achieve the highest possible output torque at the working components. In one heavy-duty truck, the gearbox lost its working capacity due to the failure of its vital parts: a tapered roller bearing and a helical gear. The analysis presented in this paper, conducted on the basis of experimental and analytical methods, showed that, due to inadequate installation of the bearings’ outer ring in the gearbox housing in one intermediate shaft support, the roller bearing performed its elementary function in very unfavorable working conditions of mechanical and thermal nature. Due to the damage accumulation, the roller bearing gradually lost its working capacity. As a result, the intensity of the working conditions of the entire gearbox increased. At the moment when they reached the critical value from the aspect of the gear teeth bending strength, volumetric destruction occurred, i.e fracture of the helical gear tooth, and thus the cessation of gearbox power transmission.

Efforts to reduce greenhouse gas emissions from today’s increasing number of cars and trucks, are crucial in counteracting global warming. These efforts include the intent to reduce the effects of the resistive forces acting on the vehicle. Rolling resistance is one of these forces. A reduction in rolling resistance would aid in reducing greenhouse gas emissions, while also reducing the driving costs and increasing the driving range per charge for electric vehicles. This PhD research contributes to these efforts by the development of a rolling resistance measurement method on a flat track test equipment that avoids the curvature effects present in the standardised drum test. Another contribution is the development of a rolling resistance model that can describe the relationship between the tyre deformation and the forces acting on the tyre. The model is parametrised by results from the developed measurement method and is simple enough to be included in complete vehicle dynamicssimulations. In this thesis, the effects of different operational conditions, such as inflation pressure, tyre temperature, speed, load, road surface or tyre angles, are investigated and presented. The results from this investigation were used for the development of the measurement method for flat track test equipment. Tyre temperature is an important operating condition influencing rolling resistance and the proposed measurement method can be used to investigate rolling resistance at different tyre temperatures. The results obtained with the proposedmeasurement method, which are comparable to drum measurements performed under the same operating conditions, are used to parameterise the developed rolling resistance model. The model gives a good fit for the relationship between rolling resistance and tyre deformation. The measurement method and the model build a good platform for deeper investigations of rolling resistance and its connection to tyre temperature., Arbete för att minska utsläppen av växthusgaser från det ökande antalet bilar och lastbilar är en viktig del i att motverka den globala uppvärmningen. Detta kan göras genom att reducera påverkan från de resistiva krafter som påverkar fordonet, med fokus på rullmotståndet. En minskning av fordonens rullmotstånd skulle medverka till att minska växthusgasutsläppen samt bidra till att reducera körkostnaderna och öka räckvidden per laddning för elbilar.Denna licentiatuppsats bidrar till detta genom att skapa en metod för rullmotståndsmätningar på plant underlag, för att kunna undvikakrökningseffekterna i den standardiserade trummätningen. Ett annatbidrag är en rullmotståndsmodell som beskriver växelverkan mellan däckdeformationer och däckkrafter. Modellen parametriseras med resultat från den framtagna mätmetoden och är tillräckligt enkel för att vara användbar i en komplett fordonsdynamiksimulering. I denna uppsats presenteras påverkan av olika driftsvillkor som däcktryck, däcktemperatur, hastighet, last, underlag och kurvatur. Dessa resultat nyttjades i utvecklandet av nämnda mätmetod för rullmotståndsmätningar på plant underlag. Däcktemperatur är ett viktigt driftsförhållande med stor påverkan på rullmotståndet och den föreslagna mätmetoden kan användas för att mäta rullmotstånd vid olika däcktemperaturer. Denna mätmetod användes sedan för att parametrisera indata till den utvecklade rullmotståndsmodellen. Det visade sig att modelldata avviker från uppmätt data för förhållandet mellan hjullast och däckdeformation på grund av modellgeometrin. Men modellen ger en god överenstämmelse för förhållandet mellan däckdeformation och rullmotstånd. Mätmetoden är, tillsammans med den föreslagna modellen, en bra bas för mer genomgående undersökningar av rullmotstånd och dess korrelation med däcktemperatur.

Efforts to reduce greenhouse gas emissions from today’s increasing number of cars and trucks, are crucial in counteracting global warming. These efforts include the intent to reduce the effects of the resistive forces acting on the vehicle. Rolling resistance is one of these forces. A reduction in rolling resistance would aid in reducing greenhouse gas emissions, while also reducing the driving costs and increasing the driving range per charge for electric vehicles. This PhD research contributes to these efforts by the development of a rolling resistance measurement method on a flat track test equipment that avoids the curvature effects present in the standardised drum test. Another contribution is the development of a rolling resistance model that can describe the relationship between the tyre deformation and the forces acting on the tyre. The model is parametrised by results from the developed measurement method and is simple enough to be included in complete vehicle dynamicssimulations. In this thesis, the effects of different operational conditions, such as inflation pressure, tyre temperature, speed, load, road surface or tyre angles, are investigated and presented. The results from this investigation were used for the development of the measurement method for flat track test equipment. Tyre temperature is an important operating condition influencing rolling resistance and the proposed measurement method can be used to investigate rolling resistance at different tyre temperatures. The results obtained with the proposedmeasurement method, which are comparable to drum measurements performed under the same operating conditions, are used to parameterise the developed rolling resistance model. The model gives a good fit for the relationship between rolling resistance and tyre deformation. The measurement method and the model build a good platform for deeper investigations of rolling resistance and its connection to tyre temperature., Arbete för att minska utsläppen av växthusgaser från det ökande antalet bilar och lastbilar är en viktig del i att motverka den globala uppvärmningen. Detta kan göras genom att reducera påverkan från de resistiva krafter som påverkar fordonet, med fokus på rullmotståndet. En minskning av fordonens rullmotstånd skulle medverka till att minska växthusgasutsläppen samt bidra till att reducera körkostnaderna och öka räckvidden per laddning för elbilar.Denna licentiatuppsats bidrar till detta genom att skapa en metod för rullmotståndsmätningar på plant underlag, för att kunna undvikakrökningseffekterna i den standardiserade trummätningen. Ett annatbidrag är en rullmotståndsmodell som beskriver växelverkan mellan däckdeformationer och däckkrafter. Modellen parametriseras med resultat från den framtagna mätmetoden och är tillräckligt enkel för att vara användbar i en komplett fordonsdynamiksimulering. I denna uppsats presenteras påverkan av olika driftsvillkor som däcktryck, däcktemperatur, hastighet, last, underlag och kurvatur. Dessa resultat nyttjades i utvecklandet av nämnda mätmetod för rullmotståndsmätningar på plant underlag. Däcktemperatur är ett viktigt driftsförhållande med stor påverkan på rullmotståndet och den föreslagna mätmetoden kan användas för att mäta rullmotstånd vid olika däcktemperaturer. Denna mätmetod användes sedan för att parametrisera indata till den utvecklade rullmotståndsmodellen. Det visade sig att modelldata avviker från uppmätt data för förhållandet mellan hjullast och däckdeformation på grund av modellgeometrin. Men modellen ger en god överenstämmelse för förhållandet mellan däckdeformation och rullmotstånd. Mätmetoden är, tillsammans med den föreslagna modellen, en bra bas för mer genomgående undersökningar av rullmotstånd och dess korrelation med däcktemperatur.

Efforts to reduce greenhouse gas emissions from today’s increasing number of cars and trucks, are crucial in counteracting global warming. These efforts include the intent to reduce the effects of the resistive forces acting on the vehicle. Rolling resistance is one of these forces. A reduction in rolling resistance would aid in reducing greenhouse gas emissions, while also reducing the driving costs and increasing the driving range per charge for electric vehicles. This PhD research contributes to these efforts by the development of a rolling resistance measurement method on a flat track test equipment that avoids the curvature effects present in the standardised drum test. Another contribution is the development of a rolling resistance model that can describe the relationship between the tyre deformation and the forces acting on the tyre. The model is parametrised by results from the developed measurement method and is simple enough to be included in complete vehicle dynamicssimulations. In this thesis, the effects of different operational conditions, such as inflation pressure, tyre temperature, speed, load, road surface or tyre angles, are investigated and presented. The results from this investigation were used for the development of the measurement method for flat track test equipment. Tyre temperature is an important operating condition influencing rolling resistance and the proposed measurement method can be used to investigate rolling resistance at different tyre temperatures. The results obtained with the proposedmeasurement method, which are comparable to drum measurements performed under the same operating conditions, are used to parameterise the developed rolling resistance model. The model gives a good fit for the relationship between rolling resistance and tyre deformation. The measurement method and the model build a good platform for deeper investigations of rolling resistance and its connection to tyre temperature., Arbete för att minska utsläppen av växthusgaser från det ökande antalet bilar och lastbilar är en viktig del i att motverka den globala uppvärmningen. Detta kan göras genom att reducera påverkan från de resistiva krafter som påverkar fordonet, med fokus på rullmotståndet. En minskning av fordonens rullmotstånd skulle medverka till att minska växthusgasutsläppen samt bidra till att reducera körkostnaderna och öka räckvidden per laddning för elbilar.Denna licentiatuppsats bidrar till detta genom att skapa en metod för rullmotståndsmätningar på plant underlag, för att kunna undvikakrökningseffekterna i den standardiserade trummätningen. Ett annatbidrag är en rullmotståndsmodell som beskriver växelverkan mellan däckdeformationer och däckkrafter. Modellen parametriseras med resultat från den framtagna mätmetoden och är tillräckligt enkel för att vara användbar i en komplett fordonsdynamiksimulering. I denna uppsats presenteras påverkan av olika driftsvillkor som däcktryck, däcktemperatur, hastighet, last, underlag och kurvatur. Dessa resultat nyttjades i utvecklandet av nämnda mätmetod för rullmotståndsmätningar på plant underlag. Däcktemperatur är ett viktigt driftsförhållande med stor påverkan på rullmotståndet och den föreslagna mätmetoden kan användas för att mäta rullmotstånd vid olika däcktemperaturer. Denna mätmetod användes sedan för att parametrisera indata till den utvecklade rullmotståndsmodellen. Det visade sig att modelldata avviker från uppmätt data för förhållandet mellan hjullast och däckdeformation på grund av modellgeometrin. Men modellen ger en god överenstämmelse för förhållandet mellan däckdeformation och rullmotstånd. Mätmetoden är, tillsammans med den föreslagna modellen, en bra bas för mer genomgående undersökningar av rullmotstånd och dess korrelation med däcktemperatur.

Biofuels are a viable alternative to the partial or total replacement of fossil fuels, biodiesel is an ideal substitute for diesel as it can be used without modifying existing engines and offers a safe distribution process. In this review, the raw materials used in recent years for their production by the transesterification method are summarized, as well as the effect that the operating conditions have on the reaction yield, in addition to integrating the reaction mechanisms with base catalysis, acid and the heterogeneous catalyst CaO. Transesterification has been studied and modified, from the conventional process to the application of ultrasound, in supercritical conditions and in situ. The ideal process will depend on the available raw materials and equipment, using the least amount of energy, time and inputs, one of the most promising is transesterification with ultrasound and heterogeneous catalyst., Los biocombustibles son una alternativa viable a la sustitución parcial o total de los combustibles fósiles, por consiguiente, el biodiésel es una opción para suplir al diésel, ya que puede utilizarse sin modificar los motores existentes y ofrecer un proceso de distribución seguro. En esta revisión, se resumen las materias primas utilizadas en los últimos años para su producción mediante el método de la transesterificación, así como el efecto que las condiciones de operación tienen en el rendimiento y mecanismos de reacción y que se presentan al utilizar las catálisis básica, ácida y heterogénea con el catalizador CaO. La transesterificación se ha estudiado y modificado, desde el proceso convencional hasta la aplicación del ultrasonido, en condiciones supercríticas e in situ. El proceso idóneo dependerá de las materias primas y los equipos disponibles, utilizando la menor cantidad de energía, tiempo e insumos, uno de los más prometedores es la transesterificación con ultrasonido y un catalizador heterogéneo.

Efforts to reduce greenhouse gas emissions from today’s increasing number of cars and trucks, are crucial in counteracting global warming. These efforts include the intent to reduce the effects of the resistive forces acting on the vehicle. Rolling resistance is one of these forces. A reduction in rolling resistance would aid in reducing greenhouse gas emissions, while also reducing the driving costs and increasing the driving range per charge for electric vehicles. This PhD research contributes to these efforts by the development of a rolling resistance measurement method on a flat track test equipment that avoids the curvature effects present in the standardised drum test. Another contribution is the development of a rolling resistance model that can describe the relationship between the tyre deformation and the forces acting on the tyre. The model is parametrised by results from the developed measurement method and is simple enough to be included in complete vehicle dynamicssimulations. In this thesis, the effects of different operational conditions, such as inflation pressure, tyre temperature, speed, load, road surface or tyre angles, are investigated and presented. The results from this investigation were used for the development of the measurement method for flat track test equipment. Tyre temperature is an important operating condition influencing rolling resistance and the proposed measurement method can be used to investigate rolling resistance at different tyre temperatures. The results obtained with the proposedmeasurement method, which are comparable to drum measurements performed under the same operating conditions, are used to parameterise the developed rolling resistance model. The model gives a good fit for the relationship between rolling resistance and tyre deformation. The measurement method and the model build a good platform for deeper investigations of rolling resistance and its connection to tyre temperature., Arbete för att minska utsläppen av växthusgaser från det ökande antalet bilar och lastbilar är en viktig del i att motverka den globala uppvärmningen. Detta kan göras genom att reducera påverkan från de resistiva krafter som påverkar fordonet, med fokus på rullmotståndet. En minskning av fordonens rullmotstånd skulle medverka till att minska växthusgasutsläppen samt bidra till att reducera körkostnaderna och öka räckvidden per laddning för elbilar.Denna licentiatuppsats bidrar till detta genom att skapa en metod för rullmotståndsmätningar på plant underlag, för att kunna undvikakrökningseffekterna i den standardiserade trummätningen. Ett annatbidrag är en rullmotståndsmodell som beskriver växelverkan mellan däckdeformationer och däckkrafter. Modellen parametriseras med resultat från den framtagna mätmetoden och är tillräckligt enkel för att vara användbar i en komplett fordonsdynamiksimulering. I denna uppsats presenteras påverkan av olika driftsvillkor som däcktryck, däcktemperatur, hastighet, last, underlag och kurvatur. Dessa resultat nyttjades i utvecklandet av nämnda mätmetod för rullmotståndsmätningar på plant underlag. Däcktemperatur är ett viktigt driftsförhållande med stor påverkan på rullmotståndet och den föreslagna mätmetoden kan användas för att mäta rullmotstånd vid olika däcktemperaturer. Denna mätmetod användes sedan för att parametrisera indata till den utvecklade rullmotståndsmodellen. Det visade sig att modelldata avviker från uppmätt data för förhållandet mellan hjullast och däckdeformation på grund av modellgeometrin. Men modellen ger en god överenstämmelse för förhållandet mellan däckdeformation och rullmotstånd. Mätmetoden är, tillsammans med den föreslagna modellen, en bra bas för mer genomgående undersökningar av rullmotstånd och dess korrelation med däcktemperatur.

Efforts to reduce greenhouse gas emissions from today’s increasing number of cars and trucks, are crucial in counteracting global warming. These efforts include the intent to reduce the effects of the resistive forces acting on the vehicle. Rolling resistance is one of these forces. A reduction in rolling resistance would aid in reducing greenhouse gas emissions, while also reducing the driving costs and increasing the driving range per charge for electric vehicles. This PhD research contributes to these efforts by the development of a rolling resistance measurement method on a flat track test equipment that avoids the curvature effects present in the standardised drum test. Another contribution is the development of a rolling resistance model that can describe the relationship between the tyre deformation and the forces acting on the tyre. The model is parametrised by results from the developed measurement method and is simple enough to be included in complete vehicle dynamicssimulations. In this thesis, the effects of different operational conditions, such as inflation pressure, tyre temperature, speed, load, road surface or tyre angles, are investigated and presented. The results from this investigation were used for the development of the measurement method for flat track test equipment. Tyre temperature is an important operating condition influencing rolling resistance and the proposed measurement method can be used to investigate rolling resistance at different tyre temperatures. The results obtained with the proposedmeasurement method, which are comparable to drum measurements performed under the same operating conditions, are used to parameterise the developed rolling resistance model. The model gives a good fit for the relationship between rolling resistance and tyre deformation. The measurement method and the model build a good platform for deeper investigations of rolling resistance and its connection to tyre temperature., Arbete för att minska utsläppen av växthusgaser från det ökande antalet bilar och lastbilar är en viktig del i att motverka den globala uppvärmningen. Detta kan göras genom att reducera påverkan från de resistiva krafter som påverkar fordonet, med fokus på rullmotståndet. En minskning av fordonens rullmotstånd skulle medverka till att minska växthusgasutsläppen samt bidra till att reducera körkostnaderna och öka räckvidden per laddning för elbilar.Denna licentiatuppsats bidrar till detta genom att skapa en metod för rullmotståndsmätningar på plant underlag, för att kunna undvikakrökningseffekterna i den standardiserade trummätningen. Ett annatbidrag är en rullmotståndsmodell som beskriver växelverkan mellan däckdeformationer och däckkrafter. Modellen parametriseras med resultat från den framtagna mätmetoden och är tillräckligt enkel för att vara användbar i en komplett fordonsdynamiksimulering. I denna uppsats presenteras påverkan av olika driftsvillkor som däcktryck, däcktemperatur, hastighet, last, underlag och kurvatur. Dessa resultat nyttjades i utvecklandet av nämnda mätmetod för rullmotståndsmätningar på plant underlag. Däcktemperatur är ett viktigt driftsförhållande med stor påverkan på rullmotståndet och den föreslagna mätmetoden kan användas för att mäta rullmotstånd vid olika däcktemperaturer. Denna mätmetod användes sedan för att parametrisera indata till den utvecklade rullmotståndsmodellen. Det visade sig att modelldata avviker från uppmätt data för förhållandet mellan hjullast och däckdeformation på grund av modellgeometrin. Men modellen ger en god överenstämmelse för förhållandet mellan däckdeformation och rullmotstånd. Mätmetoden är, tillsammans med den föreslagna modellen, en bra bas för mer genomgående undersökningar av rullmotstånd och dess korrelation med däcktemperatur.

Efforts to reduce greenhouse gas emissions from today’s increasing number of cars and trucks, are crucial in counteracting global warming. These efforts include the intent to reduce the effects of the resistive forces acting on the vehicle. Rolling resistance is one of these forces. A reduction in rolling resistance would aid in reducing greenhouse gas emissions, while also reducing the driving costs and increasing the driving range per charge for electric vehicles. This PhD research contributes to these efforts by the development of a rolling resistance measurement method on a flat track test equipment that avoids the curvature effects present in the standardised drum test. Another contribution is the development of a rolling resistance model that can describe the relationship between the tyre deformation and the forces acting on the tyre. The model is parametrised by results from the developed measurement method and is simple enough to be included in complete vehicle dynamicssimulations. In this thesis, the effects of different operational conditions, such as inflation pressure, tyre temperature, speed, load, road surface or tyre angles, are investigated and presented. The results from this investigation were used for the development of the measurement method for flat track test equipment. Tyre temperature is an important operating condition influencing rolling resistance and the proposed measurement method can be used to investigate rolling resistance at different tyre temperatures. The results obtained with the proposedmeasurement method, which are comparable to drum measurements performed under the same operating conditions, are used to parameterise the developed rolling resistance model. The model gives a good fit for the relationship between rolling resistance and tyre deformation. The measurement method and the model build a good platform for deeper investigations of rolling resistance and its connection to tyre temperature., Arbete för att minska utsläppen av växthusgaser från det ökande antalet bilar och lastbilar är en viktig del i att motverka den globala uppvärmningen. Detta kan göras genom att reducera påverkan från de resistiva krafter som påverkar fordonet, med fokus på rullmotståndet. En minskning av fordonens rullmotstånd skulle medverka till att minska växthusgasutsläppen samt bidra till att reducera körkostnaderna och öka räckvidden per laddning för elbilar.Denna licentiatuppsats bidrar till detta genom att skapa en metod för rullmotståndsmätningar på plant underlag, för att kunna undvikakrökningseffekterna i den standardiserade trummätningen. Ett annatbidrag är en rullmotståndsmodell som beskriver växelverkan mellan däckdeformationer och däckkrafter. Modellen parametriseras med resultat från den framtagna mätmetoden och är tillräckligt enkel för att vara användbar i en komplett fordonsdynamiksimulering. I denna uppsats presenteras påverkan av olika driftsvillkor som däcktryck, däcktemperatur, hastighet, last, underlag och kurvatur. Dessa resultat nyttjades i utvecklandet av nämnda mätmetod för rullmotståndsmätningar på plant underlag. Däcktemperatur är ett viktigt driftsförhållande med stor påverkan på rullmotståndet och den föreslagna mätmetoden kan användas för att mäta rullmotstånd vid olika däcktemperaturer. Denna mätmetod användes sedan för att parametrisera indata till den utvecklade rullmotståndsmodellen. Det visade sig att modelldata avviker från uppmätt data för förhållandet mellan hjullast och däckdeformation på grund av modellgeometrin. Men modellen ger en god överenstämmelse för förhållandet mellan däckdeformation och rullmotstånd. Mätmetoden är, tillsammans med den föreslagna modellen, en bra bas för mer genomgående undersökningar av rullmotstånd och dess korrelation med däcktemperatur.

Efforts to reduce greenhouse gas emissions from today’s increasing number of cars and trucks, are crucial in counteracting global warming. These efforts include the intent to reduce the effects of the resistive forces acting on the vehicle. Rolling resistance is one of these forces. A reduction in rolling resistance would aid in reducing greenhouse gas emissions, while also reducing the driving costs and increasing the driving range per charge for electric vehicles. This PhD research contributes to these efforts by the development of a rolling resistance measurement method on a flat track test equipment that avoids the curvature effects present in the standardised drum test. Another contribution is the development of a rolling resistance model that can describe the relationship between the tyre deformation and the forces acting on the tyre. The model is parametrised by results from the developed measurement method and is simple enough to be included in complete vehicle dynamicssimulations. In this thesis, the effects of different operational conditions, such as inflation pressure, tyre temperature, speed, load, road surface or tyre angles, are investigated and presented. The results from this investigation were used for the development of the measurement method for flat track test equipment. Tyre temperature is an important operating condition influencing rolling resistance and the proposed measurement method can be used to investigate rolling resistance at different tyre temperatures. The results obtained with the proposedmeasurement method, which are comparable to drum measurements performed under the same operating conditions, are used to parameterise the developed rolling resistance model. The model gives a good fit for the relationship between rolling resistance and tyre deformation. The measurement method and the model build a good platform for deeper investigations of rolling resistance and its connection to tyre temperature., Arbete för att minska utsläppen av växthusgaser från det ökande antalet bilar och lastbilar är en viktig del i att motverka den globala uppvärmningen. Detta kan göras genom att reducera påverkan från de resistiva krafter som påverkar fordonet, med fokus på rullmotståndet. En minskning av fordonens rullmotstånd skulle medverka till att minska växthusgasutsläppen samt bidra till att reducera körkostnaderna och öka räckvidden per laddning för elbilar.Denna licentiatuppsats bidrar till detta genom att skapa en metod för rullmotståndsmätningar på plant underlag, för att kunna undvikakrökningseffekterna i den standardiserade trummätningen. Ett annatbidrag är en rullmotståndsmodell som beskriver växelverkan mellan däckdeformationer och däckkrafter. Modellen parametriseras med resultat från den framtagna mätmetoden och är tillräckligt enkel för att vara användbar i en komplett fordonsdynamiksimulering. I denna uppsats presenteras påverkan av olika driftsvillkor som däcktryck, däcktemperatur, hastighet, last, underlag och kurvatur. Dessa resultat nyttjades i utvecklandet av nämnda mätmetod för rullmotståndsmätningar på plant underlag. Däcktemperatur är ett viktigt driftsförhållande med stor påverkan på rullmotståndet och den föreslagna mätmetoden kan användas för att mäta rullmotstånd vid olika däcktemperaturer. Denna mätmetod användes sedan för att parametrisera indata till den utvecklade rullmotståndsmodellen. Det visade sig att modelldata avviker från uppmätt data för förhållandet mellan hjullast och däckdeformation på grund av modellgeometrin. Men modellen ger en god överenstämmelse för förhållandet mellan däckdeformation och rullmotstånd. Mätmetoden är, tillsammans med den föreslagna modellen, en bra bas för mer genomgående undersökningar av rullmotstånd och dess korrelation med däcktemperatur.

Efforts to reduce greenhouse gas emissions from today’s increasing number of cars and trucks, are crucial in counteracting global warming. These efforts include the intent to reduce the effects of the resistive forces acting on the vehicle. Rolling resistance is one of these forces. A reduction in rolling resistance would aid in reducing greenhouse gas emissions, while also reducing the driving costs and increasing the driving range per charge for electric vehicles. This PhD research contributes to these efforts by the development of a rolling resistance measurement method on a flat track test equipment that avoids the curvature effects present in the standardised drum test. Another contribution is the development of a rolling resistance model that can describe the relationship between the tyre deformation and the forces acting on the tyre. The model is parametrised by results from the developed measurement method and is simple enough to be included in complete vehicle dynamicssimulations. In this thesis, the effects of different operational conditions, such as inflation pressure, tyre temperature, speed, load, road surface or tyre angles, are investigated and presented. The results from this investigation were used for the development of the measurement method for flat track test equipment. Tyre temperature is an important operating condition influencing rolling resistance and the proposed measurement method can be used to investigate rolling resistance at different tyre temperatures. The results obtained with the proposedmeasurement method, which are comparable to drum measurements performed under the same operating conditions, are used to parameterise the developed rolling resistance model. The model gives a good fit for the relationship between rolling resistance and tyre deformation. The measurement method and the model build a good platform for deeper investigations of rolling resistance and its connection to tyre temperature., Arbete för att minska utsläppen av växthusgaser från det ökande antalet bilar och lastbilar är en viktig del i att motverka den globala uppvärmningen. Detta kan göras genom att reducera påverkan från de resistiva krafter som påverkar fordonet, med fokus på rullmotståndet. En minskning av fordonens rullmotstånd skulle medverka till att minska växthusgasutsläppen samt bidra till att reducera körkostnaderna och öka räckvidden per laddning för elbilar.Denna licentiatuppsats bidrar till detta genom att skapa en metod för rullmotståndsmätningar på plant underlag, för att kunna undvikakrökningseffekterna i den standardiserade trummätningen. Ett annatbidrag är en rullmotståndsmodell som beskriver växelverkan mellan däckdeformationer och däckkrafter. Modellen parametriseras med resultat från den framtagna mätmetoden och är tillräckligt enkel för att vara användbar i en komplett fordonsdynamiksimulering. I denna uppsats presenteras påverkan av olika driftsvillkor som däcktryck, däcktemperatur, hastighet, last, underlag och kurvatur. Dessa resultat nyttjades i utvecklandet av nämnda mätmetod för rullmotståndsmätningar på plant underlag. Däcktemperatur är ett viktigt driftsförhållande med stor påverkan på rullmotståndet och den föreslagna mätmetoden kan användas för att mäta rullmotstånd vid olika däcktemperaturer. Denna mätmetod användes sedan för att parametrisera indata till den utvecklade rullmotståndsmodellen. Det visade sig att modelldata avviker från uppmätt data för förhållandet mellan hjullast och däckdeformation på grund av modellgeometrin. Men modellen ger en god överenstämmelse för förhållandet mellan däckdeformation och rullmotstånd. Mätmetoden är, tillsammans med den föreslagna modellen, en bra bas för mer genomgående undersökningar av rullmotstånd och dess korrelation med däcktemperatur.

Biofuels are a viable alternative to the partial or total replacement of fossil fuels, biodiesel is an ideal substitute for diesel as it can be used without modifying existing engines and offers a safe distribution process. In this review, the raw materials used in recent years for their production by the transesterification method are summarized, as well as the effect that the operating conditions have on the reaction yield, in addition to integrating the reaction mechanisms with base catalysis, acid and the heterogeneous catalyst CaO. Transesterification has been studied and modified, from the conventional process to the application of ultrasound, in supercritical conditions and in situ. The ideal process will depend on the available raw materials and equipment, using the least amount of energy, time and inputs, one of the most promising is transesterification with ultrasound and heterogeneous catalyst., Los biocombustibles son una alternativa viable a la sustitución parcial o total de los combustibles fósiles, por consiguiente, el biodiésel es una opción para suplir al diésel, ya que puede utilizarse sin modificar los motores existentes y ofrecer un proceso de distribución seguro. En esta revisión, se resumen las materias primas utilizadas en los últimos años para su producción mediante el método de la transesterificación, así como el efecto que las condiciones de operación tienen en el rendimiento y mecanismos de reacción y que se presentan al utilizar las catálisis básica, ácida y heterogénea con el catalizador CaO. La transesterificación se ha estudiado y modificado, desde el proceso convencional hasta la aplicación del ultrasonido, en condiciones supercríticas e in situ. El proceso idóneo dependerá de las materias primas y los equipos disponibles, utilizando la menor cantidad de energía, tiempo e insumos, uno de los más prometedores es la transesterificación con ultrasonido y un catalizador heterogéneo.

The load angle of a synchronous generator connected to a power grid has an eigenfrequency that depends on the operating conditions. The existence of an eigenfrequency can make the generator sensitive to electrical and mechanical disturbances and motivates the use of damper windings and power stabilizing systems. Another reason for keeping load angle oscillations small is that they increase the eddy current losses in the stator core and clamping structure due to axial leakage flux. This is shown with transient finite element analyses and can be explained by a loss model derived from a phasor model of the eddy current loss density., Title in thesis list of papers: A Loss Model and Finite Element Analyses of the Influence of Load Angle Oscillation on Stator Eddy Current Losses in a Synchronous Generator

The load angle of a synchronous generator connected to a power grid has an eigenfrequency that depends on the operating conditions. The existence of an eigenfrequency can make the generator sensitive to electrical and mechanical disturbances and motivates the use of damper windings and power stabilizing systems. Another reason for keeping load angle oscillations small is that they increase the eddy current losses in the stator core and clamping structure due to axial leakage flux. This is shown with transient finite element analyses and can be explained by a loss model derived from a phasor model of the eddy current loss density., Title in thesis list of papers: A Loss Model and Finite Element Analyses of the Influence of Load Angle Oscillation on Stator Eddy Current Losses in a Synchronous Generator

The load angle of a synchronous generator connected to a power grid has an eigenfrequency that depends on the operating conditions. The existence of an eigenfrequency can make the generator sensitive to electrical and mechanical disturbances and motivates the use of damper windings and power stabilizing systems. Another reason for keeping load angle oscillations small is that they increase the eddy current losses in the stator core and clamping structure due to axial leakage flux. This is shown with transient finite element analyses and can be explained by a loss model derived from a phasor model of the eddy current loss density., Title in thesis list of papers: A Loss Model and Finite Element Analyses of the Influence of Load Angle Oscillation on Stator Eddy Current Losses in a Synchronous Generator

The load angle of a synchronous generator connected to a power grid has an eigenfrequency that depends on the operating conditions. The existence of an eigenfrequency can make the generator sensitive to electrical and mechanical disturbances and motivates the use of damper windings and power stabilizing systems. Another reason for keeping load angle oscillations small is that they increase the eddy current losses in the stator core and clamping structure due to axial leakage flux. This is shown with transient finite element analyses and can be explained by a loss model derived from a phasor model of the eddy current loss density., Title in thesis list of papers: A Loss Model and Finite Element Analyses of the Influence of Load Angle Oscillation on Stator Eddy Current Losses in a Synchronous Generator

The load angle of a synchronous generator connected to a power grid has an eigenfrequency that depends on the operating conditions. The existence of an eigenfrequency can make the generator sensitive to electrical and mechanical disturbances and motivates the use of damper windings and power stabilizing systems. Another reason for keeping load angle oscillations small is that they increase the eddy current losses in the stator core and clamping structure due to axial leakage flux. This is shown with transient finite element analyses and can be explained by a loss model derived from a phasor model of the eddy current loss density., Title in thesis list of papers: A Loss Model and Finite Element Analyses of the Influence of Load Angle Oscillation on Stator Eddy Current Losses in a Synchronous Generator

Vibration diagnostics is an indispensable method to evaluate the technical condition of machinery. If the conditions of machines are regularly monitored, the problems can be corrected even before they arise. The most often overloaded components of the turbine are bearings that similarly like other machinery are subject to degradation wear. The article deals with the bearingś condition of the Kaplan turbine. Within the research, the frequencies at which maximum accelerations were achieved and their impact on plant operation were observed. Time records were converted to the frequency domain by means of Fast Fourier Transformation and the records were processed by means of filters. Acceleration peaks have determined the frequencies responsible for the outer and inner ring damages, but based on an evaluation of the operating state of the bearing using Root Mean Square (RMS) values could be concluded that that damage to any part of the bearing is not demonstrable and the turbine is operability. © 2020 Int. J. Mech. Eng. Rob. Res.

Vibration diagnostics is an indispensable method to evaluate the technical condition of machinery. If the conditions of machines are regularly monitored, the problems can be corrected even before they arise. The most often overloaded components of the turbine are bearings that similarly like other machinery are subject to degradation wear. The article deals with the bearingś condition of the Kaplan turbine. Within the research, the frequencies at which maximum accelerations were achieved and their impact on plant operation were observed. Time records were converted to the frequency domain by means of Fast Fourier Transformation and the records were processed by means of filters. Acceleration peaks have determined the frequencies responsible for the outer and inner ring damages, but based on an evaluation of the operating state of the bearing using Root Mean Square (RMS) values could be concluded that that damage to any part of the bearing is not demonstrable and the turbine is operability. © 2020 Int. J. Mech. Eng. Rob. Res.

Dope D.C es una microempresa encargada de la producción de cerveza artesanal , ubicada en la ciudad de Bogotá; gracias a la gran variedad y la calidad en productos, se ve en la necesidad de aumentar su capacidad de producción, por tal motivo deciden invertir en una sala de cocción con un capacidad de producción de 120L. Debido a esto el estudiante deberá establecer las condiciones de operación en cada una de las etapas y lograr producir un estilo APA.

Dope D.C es una microempresa encargada de la producción de cerveza artesanal , ubicada en la ciudad de Bogotá; gracias a la gran variedad y la calidad en productos, se ve en la necesidad de aumentar su capacidad de producción, por tal motivo deciden invertir en una sala de cocción con un capacidad de producción de 120L. Debido a esto el estudiante deberá establecer las condiciones de operación en cada una de las etapas y lograr producir un estilo APA.

Nowadays, there is worldwide interest in diversifying energy supply. In this regard, biomass is the best possible renewable organic substitute for fossil fuels. In particular, the energy content of very wet biomass, recovered with appropriate technology, could potentially be used for power generation. In addition to power generation, this technology would represent a sanitary option to improve the quality of public health and the environment. Supercritical water gasification (SCWG) is a technology applied for the conversion of wet biomass into gas. It uses the specific physical properties of water at supercritical conditions to decompose the organic matter. However, near 100% conversion, close to thermodynamic equilibrium, of real biomass into gas is not yet demonstrated. The conversion is higher at dry biomass concentrations below 10 wt.%, but at these conditions, the system is not energetically sustainable. The conversion depends on the SCWG operating conditions and the properties of the catalyst. Because of present-day technical limitations, the conversion efficiency in SCWG is low when fed with real biomass. The net electrical efficiency of a combined system SCWG—solid oxide fuel cell (SOFC), fed with fecal sludge at 15 wt.% dry biomass, reaches between 50 and 70% (thermodynamically calculated values), whereas utilizing an SCWG designed with present-day engineering gives 29–40%. The SOFC fuel utilization influences the system efficiency significantly, as the processed heat available for the heat integration depends on fuel utilization. The extreme operating conditions of an SCWG-based system cause technical limitations toward reaching complete conversion during gasification. An efficient and stable catalyst is not yet available at competitive costs for low-temperature SCWG of real biomass. Intensive research in different gasification-SOFC system configurations that include the integration of complementary processes, such as the electrochemical oxidation of hi, Energy Technology, Process and Energy

The construction comprises a wide spectrum of variables that need to be analyzed to carry out an adequate project planning to generate profit and to comply with the project technical specifications. The objective of this research is to study the variation of costs in earthworks according to the operating conditions of the construction equipment. The sensitivity of production and production costs to the variation of the operating conditions of the construction equipment were analyzed through a probabilistic model. The effect of variations on the parameters involved in the calculation of earthwork production were analyzed for the hauling equipment in different operating scenarios, La construcción comprende un amplio espectro de variables que requieren ser analizadas para realizar una adecuada planeación, para generar utilidades y cumplir con las especificaciones del proyecto. Esta investigación tiene como objetivo estudiar la variación de los costos en los movimientos de tierras según las condiciones de operación de los equipos, se analiza mediante un modelo probabilístico la sensibilidad de la producción y los costos de producción a la variación de las condiciones de operación de los equipos para movimiento de tierras. Se investiga el efecto las variaciones en los parámetros involucrados en el cálculo de la producción en diferentes escenarios de operación de los equipos de acarreo del material excavado

The construction comprises a wide spectrum of variables that need to be analyzed to carry out an adequate project planning to generate profit and to comply with the project technical specifications. The objective of this research is to study the variation of costs in earthworks according to the operating conditions of the construction equipment. The sensitivity of production and production costs to the variation of the operating conditions of the construction equipment were analyzed through a probabilistic model. The effect of variations on the parameters involved in the calculation of earthwork production were analyzed for the hauling equipment in different operating scenarios, La construcción comprende un amplio espectro de variables que requieren ser analizadas para realizar una adecuada planeación, para generar utilidades y cumplir con las especificaciones del proyecto. Esta investigación tiene como objetivo estudiar la variación de los costos en los movimientos de tierras según las condiciones de operación de los equipos, se analiza mediante un modelo probabilístico la sensibilidad de la producción y los costos de producción a la variación de las condiciones de operación de los equipos para movimiento de tierras. Se investiga el efecto las variaciones en los parámetros involucrados en el cálculo de la producción en diferentes escenarios de operación de los equipos de acarreo del material excavado

The construction comprises a wide spectrum of variables that need to be analyzed to carry out an adequate project planning to generate profit and to comply with the project technical specifications. The objective of this research is to study the variation of costs in earthworks according to the operating conditions of the construction equipment. The sensitivity of production and production costs to the variation of the operating conditions of the construction equipment were analyzed through a probabilistic model. The effect of variations on the parameters involved in the calculation of earthwork production were analyzed for the hauling equipment in different operating scenarios, La construcción comprende un amplio espectro de variables que requieren ser analizadas para realizar una adecuada planeación, para generar utilidades y cumplir con las especificaciones del proyecto. Esta investigación tiene como objetivo estudiar la variación de los costos en los movimientos de tierras según las condiciones de operación de los equipos, se analiza mediante un modelo probabilístico la sensibilidad de la producción y los costos de producción a la variación de las condiciones de operación de los equipos para movimiento de tierras. Se investiga el efecto las variaciones en los parámetros involucrados en el cálculo de la producción en diferentes escenarios de operación de los equipos de acarreo del material excavado

Dope D.C es una microempresa encargada de la producción de cerveza artesanal , ubicada en la ciudad de Bogotá; gracias a la gran variedad y la calidad en productos, se ve en la necesidad de aumentar su capacidad de producción, por tal motivo deciden invertir en una sala de cocción con un capacidad de producción de 120L. Debido a esto el estudiante deberá establecer las condiciones de operación en cada una de las etapas y lograr producir un estilo APA.

Dope D.C es una microempresa encargada de la producción de cerveza artesanal , ubicada en la ciudad de Bogotá; gracias a la gran variedad y la calidad en productos, se ve en la necesidad de aumentar su capacidad de producción, por tal motivo deciden invertir en una sala de cocción con un capacidad de producción de 120L. Debido a esto el estudiante deberá establecer las condiciones de operación en cada una de las etapas y lograr producir un estilo APA.

The construction comprises a wide spectrum of variables that need to be analyzed to carry out an adequate project planning to generate profit and to comply with the project technical specifications. The objective of this research is to study the variation of costs in earthworks according to the operating conditions of the construction equipment. The sensitivity of production and production costs to the variation of the operating conditions of the construction equipment were analyzed through a probabilistic model. The effect of variations on the parameters involved in the calculation of earthwork production were analyzed for the hauling equipment in different operating scenarios, La construcción comprende un amplio espectro de variables que requieren ser analizadas para realizar una adecuada planeación, para generar utilidades y cumplir con las especificaciones del proyecto. Esta investigación tiene como objetivo estudiar la variación de los costos en los movimientos de tierras según las condiciones de operación de los equipos, se analiza mediante un modelo probabilístico la sensibilidad de la producción y los costos de producción a la variación de las condiciones de operación de los equipos para movimiento de tierras. Se investiga el efecto las variaciones en los parámetros involucrados en el cálculo de la producción en diferentes escenarios de operación de los equipos de acarreo del material excavado

Nowadays, there is worldwide interest in diversifying energy supply. In this regard, biomass is the best possible renewable organic substitute for fossil fuels. In particular, the energy content of very wet biomass, recovered with appropriate technology, could potentially be used for power generation. In addition to power generation, this technology would represent a sanitary option to improve the quality of public health and the environment. Supercritical water gasification (SCWG) is a technology applied for the conversion of wet biomass into gas. It uses the specific physical properties of water at supercritical conditions to decompose the organic matter. However, near 100% conversion, close to thermodynamic equilibrium, of real biomass into gas is not yet demonstrated. The conversion is higher at dry biomass concentrations below 10 wt.%, but at these conditions, the system is not energetically sustainable. The conversion depends on the SCWG operating conditions and the properties of the catalyst. Because of present-day technical limitations, the conversion efficiency in SCWG is low when fed with real biomass. The net electrical efficiency of a combined system SCWG—solid oxide fuel cell (SOFC), fed with fecal sludge at 15 wt.% dry biomass, reaches between 50 and 70% (thermodynamically calculated values), whereas utilizing an SCWG designed with present-day engineering gives 29–40%. The SOFC fuel utilization influences the system efficiency significantly, as the processed heat available for the heat integration depends on fuel utilization. The extreme operating conditions of an SCWG-based system cause technical limitations toward reaching complete conversion during gasification. An efficient and stable catalyst is not yet available at competitive costs for low-temperature SCWG of real biomass. Intensive research in different gasification-SOFC system configurations that include the integration of complementary processes, such as the electrochemical oxidation of hi, Energy Technology, Process and Energy

Dope D.C es una microempresa encargada de la producción de cerveza artesanal , ubicada en la ciudad de Bogotá; gracias a la gran variedad y la calidad en productos, se ve en la necesidad de aumentar su capacidad de producción, por tal motivo deciden invertir en una sala de cocción con un capacidad de producción de 120L. Debido a esto el estudiante deberá establecer las condiciones de operación en cada una de las etapas y lograr producir un estilo APA.

Dope D.C es una microempresa encargada de la producción de cerveza artesanal , ubicada en la ciudad de Bogotá; gracias a la gran variedad y la calidad en productos, se ve en la necesidad de aumentar su capacidad de producción, por tal motivo deciden invertir en una sala de cocción con un capacidad de producción de 120L. Debido a esto el estudiante deberá establecer las condiciones de operación en cada una de las etapas y lograr producir un estilo APA.

[EN] In this work, six identical laboratory SBRs treating simulated wastewater were operated in parallel studying the effect of three food-to-microorganisms ratio (F/M ratio; 0.20, 0.35 and 0.50 kg COD¿kg MLSS-1¿d-1), two hydraulic retention times (HRT; 24 and 16 h) and two values of number of cycles per day (3 and 6). Influence of these operational parameters on the SMPs production and reactor performance, were studied. Results indicated that the highest F/M ratio, HRT and cycles/day produced 72.7% more of SMP. In a second experimental series, biological process yielding the maximal and the minimal SMPs production were replicated and both mixed liquors (ML) and treated effluents were ultrafiltrated. The flux decay in the conditions of minimum and maximum SMPs production were 52% and 72%, when the SBRs effluents were ultrafiltrated while no significant differences in the ultrafiltration of ML were found. In terms of permeability recovery, this was lower for the case of the ML (73% and 49% of initial permeability recovered for effluent and ML ultrafiltration, respectively).

[EN] In this work, six identical laboratory SBRs treating simulated wastewater were operated in parallel studying the effect of three food-to-microorganisms ratio (F/M ratio; 0.20, 0.35 and 0.50 kg COD¿kg MLSS-1¿d-1), two hydraulic retention times (HRT; 24 and 16 h) and two values of number of cycles per day (3 and 6). Influence of these operational parameters on the SMPs production and reactor performance, were studied. Results indicated that the highest F/M ratio, HRT and cycles/day produced 72.7% more of SMP. In a second experimental series, biological process yielding the maximal and the minimal SMPs production were replicated and both mixed liquors (ML) and treated effluents were ultrafiltrated. The flux decay in the conditions of minimum and maximum SMPs production were 52% and 72%, when the SBRs effluents were ultrafiltrated while no significant differences in the ultrafiltration of ML were found. In terms of permeability recovery, this was lower for the case of the ML (73% and 49% of initial permeability recovered for effluent and ML ultrafiltration, respectively).

To ensure safe transportation of compressed natural gas, we proposed, based on the results of studies conducted, the algorithm for a method for the evaluation of combined type tanks. The method implies determining parameters of the state of gas in the process of filling a tank, taking into consideration heat exchange processes and evaluation of the stressed-strained state of the tank, considering the operating conditions and the results of technical inspection. To implement the method, the tools for detecting and determining the shape and dimensions of probable corrosive damages of the metal liner surface under the composite shell were used. It was proposed to assess the stressed-strained state of tanks, taking into consideration the operating conditions, through the development and analysis of relevant models. The possibility of obtaining reliable results in the presence of available mechanisms was proved by our own research into the patterns of loading and unloading processes. To verify correctness of construction of the simulation model at the stage of studying the stressed-strained state of the tank with consideration of the actual operating conditions, we proposed the mathematical model that takes into consideration conditions for the interaction between elements of the structure, the effect of internal gas pressure and temperature. The use of the model decreases the costs of experimental research and contributes to ensuring the reliability of simulation results. The advantage of this method is determining the estimated destruction pressure of the combined type tanks at the current state of the dangerous areas and the influence of operating conditions. The practical significance of the obtained results is determined by the possibility of their application to ensure serviceability at the design stage and when tanks are in operation., С целью безопасной транспортировки сжатого природного газа по результатам проведенных исследований предложен алгоритм метода оценки работоспособности емкостей комбинированного типа. Метод предусматривает определение параметров состояния газа в процессе заполнения емкости с учетом процессов теплообмена и оценку напряженно-деформированного состояния емкости с учетом условий эксплуатации и результатов технического осмотра. Для реализации метода использованы средства обнаружения и определения формы и размеров возможных коррозионных повреждений поверхности металлического лейнера под композитной оболочкой. Оценку напряженно-деформированного состояния емкостей с учетом условий эксплуатации предложено осуществлять путем разработки и анализа соответствующих моделей. Возможность получения достоверных результатов при наличии доступных механизмов подтверждено собственными исследованиями особенностей протекания технологических процессов загрузки и разгрузки. Для проверки правильности построения имитационной модели на этапе исследования напряженно-деформированного состояния емкости с учетом фактических условий эксплуатации, разработана математическая модель, учитывающая условия взаимодействия элементов конструкции, действие внутреннего давления газа и температуры. Использование модели сокращает затраты на экспериментальные исследования и способствует обеспечению достоверности результатов имитационного моделирования. Преимуществом метода является определение расчетного давления разрушения емкостей комбинированного типа при существующем состояния опасных зон и влияния условий эксплуатации. Практическое значение полученных результатов определяется возможностью использования с целью обеспечения работоспособности на этапе проектирования и в процессе эксплуатации емкостей, З метою безпечного транспортування стиснутого природного газу за результатами проведених досліджень запропоновано алгоритм методу оцінки працездатності ємностей комбінованого типу. Метод передбачає визначення параметрів стану газу в процесі заповнення ємності з врахуванням процесів теплообміну та оцінку напружено-деформованого стану ємності з врахуванням умов експлуатації і результатів технічного огляду. Для реалізації методу використано засоби для виявлення та визначення форми і розмірів ймовірних корозійних пошкоджень поверхні металевого лейнера під композитною оболонкою. Оцінку напружено-деформованого стану ємностей з врахуванням умов експлуатації запропоновано здійснювати шляхом розроблення та аналізу відповідних моделей. Можливість отримання достовірних результатів за наявності доступних механізмів підтверджено власними дослідженнями особливостей протікання технологічних процесів завантаження та розвантаження. Для перевірки правильності побудови імітаційної моделі на етапі дослідження напружено-деформованого стану ємності з врахуванням фактичних умов експлуатації, розроблено математичну модель, яка враховує умови взаємодії елементів конструкції, дію внутрішнього тиску газу та температури. Використання моделі скорочує затрати на експериментальні дослідження та сприяє забезпеченню достовірності результатів імітаційного моделювання. Перевагою методу є визначення розрахункового тиску руйнування ємностей комбінованого типу за наявного стану небезпечних зон та впливу умов експлуатації. Практичне значення одержаних результатів визначається можливістю використання з метою забезпечення працездатності на етапі проектування та в процесі експлуатації ємностей

This study focuses on the influence of operating conditions on Alcalase-catalyzed egg white protein hydrolysis performed in a continuously stirred tank reactor coupled with ultrafiltration module (10 kDa). The permeate flow rate did not significantly affect the degree of hydrolysis (DH), but a significant increase in process productivity was apparent above flow rate of 1.9 cm(3) min(-1). By contrast, an increase in enzyme/substrate (E/S) ratio provided an increase in DH, but a negative correlation was observed between E/S ratio and productivity. The relationship between operating conditions and antioxidant properties of the hydrolysates, measured by three methods, was studied using Box-Behnken experimental design and response surface methodology. The statistical analysis showed that each variable (impeller speed, E/S ratio, and permeate flow rate) had a significant effect on the antioxidant capacity of all tested systems. Nevertheless, obtained response functions revealed that antioxidative activity measured by DPPH, ABTS and FRAP methods were affected differently by the same operating conditions. High impeller speeds and low permeate flow rates favor ABTS while high impeller speeds and high permeate flow rates had a positive effect on the DPPH scavenging activity. On the other hand, the best results obtained with FRAP method were achieved under moderate operating conditions. The integration of the reaction and ultrafiltration membrane separation in a continuous manner appears to be a right approach to improve and intensify the enzymatic process, enabling the production of peptides with desired antioxidant activity.

Within the European context, most of the current residential building stock does not fulfil minimum thermal requirements and needs to be refurbished urgently. Quantitative internal infrared thermography can provide valuable information about the in-situ thermal transmittance of existing buildings for their future refurbishment. This paper aims to establish how operating conditions and thermophysical properties might affect the accuracy of the measured U-value using this technique. To assess the most influential operating conditions, one experimental room with a heavy single leaf-wall was chosen to develop the research in quasi steady-state conditions, with a wide temperature difference range (3.8<¿T<21°C). A statistical analysis demonstrated that the variance in thermal transmittance could mainly be predicted by changes in the outer air temperature. To analyze the impact of the thermophysical properties, specifically the heat capacity per unit of area, four unoccupied residential buildings with heavy multi-leaf walls were tested (6<¿T<10°C). The results mainly showed that the quantitative internal infrared thermography method is more accurate in heavy multi-leaf walls with high kappa values, reaching maximum deviations of 0.20%., Peer Reviewed, Postprint (author's final draft)

This study focuses on the influence of operating conditions on Alcalase-catalyzed egg white protein hydrolysis performed in a continuously stirred tank reactor coupled with ultrafiltration module (10 kDa). The permeate flow rate did not significantly affect the degree of hydrolysis (DH), but a significant increase in process productivity was apparent above flow rate of 1.9 cm(3) min(-1). By contrast, an increase in enzyme/substrate (E/S) ratio provided an increase in DH, but a negative correlation was observed between E/S ratio and productivity. The relationship between operating conditions and antioxidant properties of the hydrolysates, measured by three methods, was studied using Box-Behnken experimental design and response surface methodology. The statistical analysis showed that each variable (impeller speed, E/S ratio, and permeate flow rate) had a significant effect on the antioxidant capacity of all tested systems. Nevertheless, obtained response functions revealed that antioxidative activity measured by DPPH, ABTS and FRAP methods were affected differently by the same operating conditions. High impeller speeds and low permeate flow rates favor ABTS while high impeller speeds and high permeate flow rates had a positive effect on the DPPH scavenging activity. On the other hand, the best results obtained with FRAP method were achieved under moderate operating conditions. The integration of the reaction and ultrafiltration membrane separation in a continuous manner appears to be a right approach to improve and intensify the enzymatic process, enabling the production of peptides with desired antioxidant activity.

Due to the sensitivity of mammalian cell cultures, understanding the influence of operating conditions during a tissue generation procedure is crucial. In this regard, a detailed study of scaffold based cell culture under a perfusion flow is presented with the aid of mathematical modelling and computational fluid dynamics (CFD). With respect to the complexity of the case study, this work focuses solely on the effect of nutrient and metabolite concentrations, and the possible influence of fluid-induced shear stress on a targeted cell (cartilage) culture. The simulation set up gives the possibility of predicting the cell culture behavior under various operating conditions and scaffold designs. Thereby, the exploitation of the predictive simulation into a newly developed stochastic routine provides the opportunity of exploring improved scaffold geometry designs. This approach was applied on a common type of fibrous structure in order to increase the process efficiencies compared with the regular used formats. The suggested topology supplies a larger effective surface for cell attachment compared to the reference design while the level of shear stress is kept at the positive range of effect. Moreover, significant improvement of mass transfer is predicted for the suggested topology.

Reliability is one of the properties that customers of heavy trucks value highest.Dependent on all parts and functions of the vehicle, reliability is a complexproperty, which can normally be measured only towards the end of a developmentproject. At earlier development stages, forecasts can give valuable decision supportfor project planning.The main function of a heavy truck is to transport goods, but the truck also hasinteractive functions as the working environment of the driver. Interactivefunctions are functions experienced by the driver. They are subjective, in the senseof being person dependent, so that a system can be experienced as inadequate byone user but satisfactory by another. Examples of interactive functions of heavytrucks are climate comfort and ergonomics, which are experienced differently bydifferent drivers. Failures of these functions lead to costs and limited availabilityfor the customer. Therefore it is important to include them in reliability forecasts.The work described in this thesis concerns some elements of the system reliabilityforecast. Two studies are presented, one proposing a qualitative systemarchitecture model and the other reviewing and testing methods for evaluating theimpact of varying operating conditions. Two case studies of a truck cab in a systemreliability test were made. The first case study shows that the system architecturemodel supports reliability forecasts by including interactive functions as well asexternal factors, human and environmental, which affect function performance.The second case study shows that modelling uncertainty is crucial for interactivefunctions and recommends a method to forecast function performance while takingvarying operating conditions into account., QC 20170602

Reliability is one of the properties that customers of heavy trucks value highest.Dependent on all parts and functions of the vehicle, reliability is a complexproperty, which can normally be measured only towards the end of a developmentproject. At earlier development stages, forecasts can give valuable decision supportfor project planning.The main function of a heavy truck is to transport goods, but the truck also hasinteractive functions as the working environment of the driver. Interactivefunctions are functions experienced by the driver. They are subjective, in the senseof being person dependent, so that a system can be experienced as inadequate byone user but satisfactory by another. Examples of interactive functions of heavytrucks are climate comfort and ergonomics, which are experienced differently bydifferent drivers. Failures of these functions lead to costs and limited availabilityfor the customer. Therefore it is important to include them in reliability forecasts.The work described in this thesis concerns some elements of the system reliabilityforecast. Two studies are presented, one proposing a qualitative systemarchitecture model and the other reviewing and testing methods for evaluating theimpact of varying operating conditions. Two case studies of a truck cab in a systemreliability test were made. The first case study shows that the system architecturemodel supports reliability forecasts by including interactive functions as well asexternal factors, human and environmental, which affect function performance.The second case study shows that modelling uncertainty is crucial for interactivefunctions and recommends a method to forecast function performance while takingvarying operating conditions into account., QC 20170602