The study of Heating, Ventilation and Air Conditioning (HVAC) system performance is important to understand its energy consumption, especially for electric vehicles. The purpose of this thesis is to develop a methodology to simulate the flow within the Scania S20H cab while also capturing the thermal properties of the fluid and solids within the cab. This is done by setting up a heat-up simulation of a stationary cab in STAR-CCM+ (Siemens Industry Software Inc, Plano TX,USA). The thesis speaks about the limitations with the current methodologies and delves into the theoretical aspects of such a scenario. The new method is a complete Computational Fluid Dynamics (CFD) method that involves conjugate heat transfer, shell modeling and temperature dependent Heat Transfer Coefficient (HTC). A benchmark case is run to understand the uncertainties introduced by virtue of the shell model. When its effects are understood and deemed minimal in the context of thesis, a steady state case for the full truck model is simulated. After it was found that the physics is well captured, a fully transient case is run to validate the model against the experimental data. The simulations best capture the behaviour of low insulation and low thickness areas such as the windshield. The gap between the simulation and experiment increases with increasing thickness and insulation. The model is found to perform mostly well with some variations between regions in the cab. The thesis satisfied its objectives in developing a methodology to better ease the conceptual design process. Additionally, guidelines for the workflow of the methodology are presented along with the limitations and scope for improvement.

The oceans are a key element in our society, economy and environmental system.They cover over 70% of the worlds surface and contribute substantially to ecosystemservices such as climate management as well as to economic sectors such as foodproduction and tourism. While the importance of the oceans for climate changeand the society is generally acknowledged in science and literature, it is often notreflected in policy. Integrated Assessment Models (IAMs) which are used to advicepolicy on carbon prices often systematically omit process and damages related tothe ocean such as ocean acidification, loss of biodiversity and changes in oceancurrents.The aim of this study is to give a more detailed perspective on ocean related processesand their role and importance for the economy under climate change and to testassumptions made in the development of IAMs - and more precisely the DynamicIntegrated Climate-Economy model also referred to as the DICE model. The initialresults of the DICE model resulted in a optimal temperature trajectory with amaximum of 4 ◦C contradicting the goals set with the Paris Agreement.This thesis is the first of its kind attempt in reviewing the most recentbiophysical evidence on climate change impacts with a focus on marine systemsand incorporating these damages to market and non-market sectors into the DICEmodel. The impacts from climate change are implemented into the DICE modelthrough economic valuation of the damages and an update of the damage function.The analysis is based on the damage function used in the original DICE2016R2model as well as the suggested update presented by Hänsel et al. (2020)The results show, that incorporating marine damages into the model yields in amajor increase in economic damages particularly in the temperature range up to 2◦C.These increased damages influence the results of the optimal temperature trajectoryand give a clear indication for a more stringent climate policy, drastically limitingthe maximum temperature increase compared to the original DICE model. / Haven är en viktig del av vårt samhälle, vår ekonomi och vårt miljösystem. De täcker över 70 % av jordens yta och bidrar väsentligt till ekosystemtjänster ekosystemtjänster som klimatstyrning samt till ekonomiska sektorer som livsmedels livsmedelsproduktion och turism. Havens betydelse för klimatförändringarna och samhället och samhället är allmänt erkänd inom vetenskap och litteratur, återspeglas den ofta inteåterspeglas ofta inte i politiken. Integrerade utvärderingsmodeller (IAM) som används för att geom koldioxidpriser utelämnar ofta systematiskt processer och skador relaterade tillhavet, t.ex. havsförsurning, förlust av biologisk mångfald och förändringar ihavsströmmar.Syftet med denna studie är att ge ett mer detaljerat perspektiv på havsrelaterade processeroch deras roll och betydelse för ekonomin under klimatförändringen samt att testaantaganden som gjorts i utvecklingen av IAM - och mer exakt den dynamiskaintegrerade klimat-ekonomimodellen, även kallad DICE-modellen. De förstaresultaten av DICE-modellen resulterade i en optimal temperaturbana med ettmaximalt 4 ◦C, vilket strider mot de mål som satts upp i Parisavtalet.Denna avhandling är den första i sitt slag som granskar de senastebiofysiska bevis på klimatförändringens effekter med fokus på marina systemoch införliva dessa skador på marknads- och icke-marknadssektorer i DICEmodellen. Effekterna av klimatförändringarna implementeras i DICE-modellengenom ekonomisk värdering av skadorna och en uppdatering av skadefunktionen.Analysen baseras på den skadefunktion som används i den ursprungliga DICE2016R2modellen samt den föreslagna uppdateringen som presenteras av Hänsel et al. (2020)Resultaten visar att införandet av marina skador i modellen leder till enstor ökning av de ekonomiska skadorna, särskilt i temperaturintervallet upp till 2◦C.Dessa ökade skador påverkar resultaten av den optimala temperaturbananoch ger en tydlig indikation på en mer stringent klimatpolitik, som drastiskt begränsarden maximala temperaturökningen jämfört med den ursprungliga DICE-modellen.

Both commuting to work and long-distance travelling with one's own bicycle have been intrend for years and a large market has emerged. While the reasons on the customer side aremainly sustainability and sporting activity, the companies offer customised products for manydifferent use-cases.In this master's thesis, a transport box for bicycles is being developed that can be taken on aplane, for example, and converted into a cargo trailer at the destination. A market researchshows that such a product is already available for certain folding bikes, whereas the goal is auniversal solution for utility bikes as well as mountain bikes.The methodological development follows a standard that divides the process into four phases.After the market research, main functions of the product are identified, which are "Transport abicycle as luggage" and "Carry goods during the bicycle ride". These are then divided intosub-functions in order to find different design variants for each function, combine them intodifferent drafts with the help of a morphological box and finally evaluate according totechnical and economic criteria, so that a final draft is determined at the end of this phase. It isa hard case providing enough space for different types of bicycles, that can be converted intoa trailer by mounting two wheels on the sides and a tow bar.In phase 3, the wheel size is set at 12 inches due to small space requirements and weight, andthe material is set to ABS-plastic for reasons of sustainability and mechanical properties.The final phase involves 3D design using Fusion360 with drawing derivation and validationof the model. The model shows that the requirements regarding geometry and weight havebeen implemented and that a practical transport option for bicycles has been found. In order topotentially launch the product on the market, further investigations such as FEM analysis ordynamic simulations are necessary. / Både pendling till arbetet och långväga resor med egen cykel har varit trendigt i flera år ochen stor marknad har vuxit fram. Medan anledningarna på kundsidan främst är hållbarhet ochsportaktivitet, erbjuder företagen kundanpassade produkter för många olika användningsfall.I detta examensarbete utvecklas en transportlåda för cyklar som till exempel kan tas med påett flygplan och omvandlas till en lasttrailer på destinationen. En marknadsundersökning visaratt en sådan produkt redan finns tillgänglig för vissa hopfällbara cyklar, medan målet är enuniversell lösning för både vanliga cyklar och mountainbikes.Metodutvecklingen följer en standard som delar in processen i fyra steg. Eftermarknadsundersökningen identifieras produktens huvudfunktioner, vilka är "Transportera encykel som bagage" och "Bära varor under cykelturen". Dessa delas sedan in i underfunktionerför att hitta olika designvarianter för varje funktion, kombinera dem till olika utkast med hjälpav en morfologisk box och slutligen bedöma enligt tekniska och ekonomiska kriterier, så attett slutligt utkast bestäms i slutet av denna steg. Det är en hård väska som ger tillräckligt medutrymme för olika typer av cyklar, och som kan omvandlas till en cycelkärra genom att manmonterar två hjul på sidorna och en dragkrok.I steg 3 sätts hjulstorleken till 12 tum på grund av små utrymmesbehov och vikt, ochmaterialet sätts till ABS-plast av hållbarhetsskäl och på grund av mekaniska egenskaper.Den sista steget innebär 3D-konstruktionen i Fusion360 med ritningsframtagning ochvalidering av modellen. Modellen visar att kraven på geometri och vikt har uppfyllts och attman har hittat ett praktiskt transportalternativ för cyklar. För att potentiellt kunna introduceraprodukten på marknaden krävs ytterligare undersökningar som FEM-analys eller dynamiskasimuleringar.

Nowadays, the forestry industry still uses heavy machinery damaging both the forest and the soil. The start-up AirForestry is currently developing a sustainable way to thin and harvest trees. With their 6.2m wide electric drone carrying a harvesting tool, they can reach, thin, cut and carry trees without the need for access roads. Naturally, the drone needs to be as lightweight as possible to increase its endurance and operation range. Therefore, the first version of the drone was manufactured before the thesis with a carbon fibre laminate.  The purpose of this thesis is to study and optimize the composite structure of the drone. The first step is to characterize the existing design through experiments and simulations using the software ANSYS. Static bending loads, free vibrations, and forced vibrations are investigated against a set of predefined design requirements. This study shows that the contact surfaces between each arm and with the motor holders have high-stress concentrations compared to the rest of the arm. This means that most of the arm can be made thinner to lessen the weight with some extra reinforcement on those problematic areas.  The second step is to optimize the laminate to decrease the weight of the structure. A preliminary optimization was made and manufactured at the beginning of the thesis with strict limitations on the choice of the lamina or available thicknesses. Similar bending and vibration experiments and simulations are conducted on the new design to compare it with the older model. While the mass was expected to decrease by about 30 $\%$, the final measured weight of the arms indicates a drop of only 15 $\%$ of the mass. The model is then optimized further with more freedom in the design variables. Several variables are successively optimized: the material choice for the laminae, the thickness then of the laminae, and the angles of the plies. The mass of the structure with the final laminate has an expected decrease in mass of 45$\%$, saving more than 12kg in total / I dag använder skogsindustrin fortfarande tunga maskiner som skadar både skogen och marken. Det nystartade företaget AirForestry utvecklar för närvarande ett hållbart system för att gallra och skörda träd: en 6,2 meter breda elektriska drönare som bär ett avverkningsverktyg. Med den kan de nå, gallra, avverka och bära träd utan att behöva använda tillfartsvägar. Naturligtvis måste drönaren vara så lätt som möjligt för att öka dess uthållighet och räckvidd. Därför tillverkades den första versionen av drönaren före examensarbetet med ett kolfiberlaminat.  Syftet med detta arbete är att studera och optimera drönarens kompositstruktur. Det första steget är att karakterisera den befintliga konstruktionen genom experiment och simuleringar med hjälp av programvaran ANSYS. Statiska böjningsbelastningar, fria vibrationer och påtvingade vibrationer undersöks med avseende på en uppsättning fördefinierade konstruktionskrav. Det andra steget är att optimera laminatet för att minska strukturens vikt. En preliminär optimering gjordes och tillverkades i början av arbetet med strikta begränsningar för valet av lamina eller tillgängliga tjocklekar. Liknande böjnings- och vibrationsexperiment och simuleringar utförs på den nya konstruktionen för att jämföra den med den äldre modellen. Även om massan förväntades minska med cirka 30 $\%$, visar den slutliga uppmätta vikten på armarna att den endast minskat med 15 $\%$. Modellen optimeras sedan ytterligare med större frihet i konstruktionsvariablerna. Flera variabler optimeras successivt: materialvalet för lamellerna, lamellernas tjocklek och vinklarna på skikten. Strukturen med det slutliga laminatet får då en förväntad minskning av massan med 45 $\%$, vilket innebär en total besparing på mer än 12 kg.

In this thesis work a literature survey is done to collect published data for T-welded joints with a thickness of 5-12 mm, produced in high strength steel and treated with HFMI. In addition to this, large structures are researched. The data was evaluated in nominal stress and effective notch stress and compared with the recommended FAT value from the International Institute of Welding (IIW) for post-weld improved joints. It was concluded that not sufficient data exist for T-joints in high strength steel, especially steels of grades with yield strength greater than 450 MPa, and thicknesses of 5-12mm, neither does enough data exist for large structures. The recommended fatigue strength values from the IIW were compared. / I detta arbete så kommer en litteraturstudie att genomföras för att samla data om svetsade t- balkar med en tjocklek på 5-12 mm, av materialet höghållfasta stål och behandlade med HFMI. Stora strukturer kommer även att undersökas. Den samlade datan är utvärderad i nominell spänning och effective notch stress och jämförd med International Institute (IIW) of Welding för efterbehandlade svetsar. En slutsats är att det inte finns tillräckligt med data för svetsade t-balkar i höghållfasta stål med en tjocklek mellan 5-12 mm. Data om stora strukturer bör också utvecklas. De rekommenderade utmattningshållfasthets värden från IIW jämfördes.

För att förbättra förarmiljön i Stridsbåt 90 H (CB90 H) skapades en process baseradpå IDEO.org med faser för att analysera nuvarande lösning, identifiera problem samtlösa dessa problem. Genom enkät, intervju, workshops, fokusgrupper ochdeltagande observation med en mindre grupp väldigt erfarna användare kunde fleraproblem ringas in. För att behandla dessa problem användes teori kring kognition, såsom gestaltlagar, kognitiva processer och kognitiv feedback. Även relevantastandarder för förarmiljöer i fartyg samt ergonomi tas upp. Teorin kombineradessedan med de tidigare nämnda metoderna för att komma fram till konkretalösningar. När det fanns en bra uppfattning om hur de olika instrumenten ochreglagen skapades koncept utifrån en egen metod. Metoden är en graf som plottarvikten av synlighet mot vikten av tillgänglighet. Varje enskilt instrument och reglageplaceras därefter ut på grafen där dess synlighet och tillgänglighet motsvaras.Resultatet visade att många instrument var överflödiga för de uppgifter som tillhörföraren och att flera andra placerats ogenomtänkt. Genom att använda grafentillsammans med teorin och standarderna skapades en ny layout för förarens reglageoch instrument. En enkel visualisering skapades utifrån en konstruktionsfil. Slutligendiskuteras arbetets, resultat, relevans och trovärdighet.

In order to ensure safe travel, railway vehicles must be stable under every condition along the track. Thus, a vehicle can be certified for operation only when it can fulfil certain criteria related to the ride stability. The stability of the vehicle is highly dependent on the wheel-rail friction coefficient: higher friction results in worse ride. So, to ensure a good evaluation of the stability, the friction should be high enough during tests. The same applies to the risk of wheel flange climbing. At the present time, the wheel-rail friction can not be measured directly but there are different procedures utilized to ensure that the conditions are suitable for testing the stability of the vehicle. In this study an algorithm is proposed to estimate the wheel-rail friction coefficient by using quantities which can be measured in reality. The algorithm is tried out in computer simulations. The algorithm has two parts: in Part 1 the friction coefficient is proposed to be equal to the ratio of the total creep force divided by the normal force; in Part 2 the total creep and spin creep are estimated to observe their correlation to the estimated friction. The contact angle in Part 1 is estimated by a contact point function. In the simulations, different conditions are tried. There are four horizontal radii: tangent track, R1300m, R1000m, and R400m. Three friction coefficients are used: 0.5, 0.4 and 0.3. In addition to this, track irregularities are included. A single vehicle is simulated in two modes: capable and incapable of passive radial steering. The track irregularities caused high values of the proposed estimated friction coefficient. The values in some instances were close or equal to the input friction coefficient of the simulation. Thus, if the highest values of the estimated friction were taken over a certain distance or time, the friction of the simulation could be approximated. In most cases, the total creep was following the trend of the estimated friction. The total creep and spin creep were used as a quality factor to determine how close the estimated friction was to the simulation’s friction. In this study when the total creep was greater than 0.006 and the spin creep was less than 1.0 m-1, the estimated friction was close to the input friction. The closeness was dependent on the simulation’s friction. Higher input friction resulted in larger deviation compared to lower friction. A sensitivity analysis has been performed by deliberately introducing errors in the position of the contact point and the angle of attack. The analysis shows that the errors are not critical when the contact point is close to the tread circle. When the contact point is close to the flange, a good measurement of the wheel profile and the contact point position required to obtain accurate results. On the other hand, the errors affect the friction estimate for high spin and low total creepage. These results are discarded by the algorithm, the influence of the errors is minimized.

A swirl injector for a rocket engine being developed by \emph{AESIR} (Association of EngineeringStudents in Rocketry) was simulated with different geometric parameters. The swirl injector is usedto atomize the ethanol used as fuel and to create a spray that mixes well with the oxidizer withinthe combustion chamber. Inlet slot angle (90, 75, 60 and 45 degrees), swirl chamber length (15, 20and 25 mm) and outlet orifice diameter (3, 6 and 9 mm) were examined.Previous studies in swirl injectors show that CFD can be used to analyze the flow in such aninjector, furthermore theoretical models exist that can predict some of the general characteristicsof the flow. Previous studies have also simulated transient behavior and flow features effectingbreakup of fuel flowing through a swirl injector.A steady state simulation using Volume of Fluid (VOF) multiphase modeling and $k$-$\omega$ \emph{SST}turbulence modeling was used to simulate the swirl injector intended for the rocket engine. It wasfound that a wider outlet orifice would give a wider cone angle of spray. This is desirable in thecurrent rocket engine design as it will promote greater mixing of fuel and oxidizer higher up in thecombustion chamber. No large variances was observed when different inlet slot angles was simulated. Ashorter swirl chamber length reduced the amount of losses in energy due to viscous forces. The flowafter the outlet orifice was not simulated so the effect of turbulence kinetic energy and energylosses outside of the swirl injector have not been analyzed, previous studies have indicated thatturbulent kinetic energy does have an effect on the breakup and atomization of the fuel.It was concluded that using a wider outlet orifice of 9 mm gave the best results out of the differentgeometric parameters analyzed and the swirl chamber length should be a short as possible.

One idea to stop the increasing threat of global warming is to build a space sunshade, made up of a constellation of satellites to reflect a portion of the sunlight. These satellites need to reach an equilibrium point where they can stay in orbit with minimal adjustments. A few feasibility studies have been made in this area and the location of the equilibrium point, L1' has been found. An area that is still unclear is the best way of getting the satellites to L1'. One idea is to use electric propulsion engines , and utilizing a gravity assist around the Moon on the way to L1'. Gravity assists have mostly been performed with chemical rocket engines, so doing it with electric propulsion causes some unique issues. The goal was to find a trajectory including the gravity assist showing that this could be an effective way of transporting the satellites. To measure how effective this would be, a trajectory without a gravity assist was also created as a means of comparison. The trajectory and orbit simulations were done in the program General Missions Analysis Tool (GMAT), and the resulting trajectory took 51 days and used 83.4kg of fuel for a fuel-to-mass-ratio of 21.5%. This was a worse result compared to the trajectory without a gravity assist, which only used 80.4kg of fuel. Finally a discussion around a potential trajectory which was shown to have a much greater velocity increase was had, which would indicate that a gravity assist maneuver could provide a trajectory that does save on fuel compared to using no gravity assist.

The evolution of electronics in the vehicle industry has introduced the possibility for more X-by-wire systems in future vehicles. However, the use of steer-by-wire systems has not yet been widelyimplemented. This opens up an opportunity to explore strategies around the potential use of such asystem.The purpose of the project was to evaluate how to design a variable steering ratio which would give asuitable ratio in all speeds. This would, in turn, make it possible to reduce the need for large steeringwheel angles. Additionally, steering wheel designs which can be implemented with a steer-by-wiresystems are discussed and what possibilities there are to move certain interfaces to the steering wheel.The evaluation process consisted of driving a real car with a constant steering ratio in normal trafficand later modelling a variable steering ratio and testing it in a simulator. This was to get data on howlarge steering wheel angles that are needed in different driving scenarios to then be able to design asuitable variable steering ratio. The tests conducted on normal roads in a real car has shown that thedriver utilises the whole steering range (full lock-lock distance) at speeds below 30 km/h and about±10° on the steering wheel at high speeds. The tests conducted in the simulator show that the variablesteering ratio presented in this report decreases the workload on the driver most of all at speeds below30 km/h.The variable steering ratio presented has been compared with a fixed steering ratio in the simulatorand the tests show that the variable steering ratio works similar to the fixed steering ratio in the samescenarios. The variable steering ratio also decreases the need for a steering wheel angle greater than±180°.