Accelerated carbonation is a new CO2 storage method under development as a solution for climate change caused by anthropogenic activities. In accelerated carbonation an alkaline source such as minerals or industrial residues react with carbon dioxide in a presence of slightly acidic solution to produce stable solid carbonates. There are varieties of accelerated carbonation routes which differ in process condition.</p><p>The aim of this study was to evaluate and compare the potential of a slurry route process and a wet route process for the carbonation of basic oxygen furnace (BOF) slag using the CO2 emitted by a conventional natural gas power plant.</p><p>For this purpose a life cycle assessment (LCA) study was performed based on principles and guidelines provided by ISO 14040:2006 and routines and data provided by the SimaPro v8 software package. The material and energy requirements for each of the steps involved in the carbonation process, i.e. pre-treatment of raw material, CO2 compression, transportation, carbonation step, after-treatment and landfill, were calculated and included in the LCA study.</p><p>The slurry and wet route resulted in net CO2 reduction of 87.4% and 72.3% respectively.  However, a positive contribution to other environmental issues was observed with the wet route leading to higher impact mainly due to high heating requirement. An exception was contribution of slurry route to abiotic resource depletion, which was higher for the slurry route due to high water requirement. A general conclusion was that the electricity consumption is the main cause of environmental issues. Sensitivity analyses showed that the environmental impacts are dependent on the transportation distance and electricity source, while no dependence was observed with respect to construction of the carbonation plant.

This paper presents conora, a robust trajectory optimization software utilizing orthogonal collocation methods for ascending rocket stages, targeting applications in early phases of mission design. The proposed methodology leverages orthogonal collocation techniques, preferred over the multitude of available options for their robustness to inaccuracies in the initial guess. This, together with low amount of available data about the ascent profile, often makes preliminary optimization considerably complex, extremely case-specific and, consequently, very time consuming. The software here implemented addresses the problem of maximizing the payload mass of a rocket by providing the required flexibility to adapt to any mission scenario disregarding of the celestial body, launch site, vehicle design and target orbit. Proper functionality is demonstrated by replicating existing missions, simplifying and reducing to the bare minimum the number of inputs. Ariane V ascending to GTO, Electron launch to SSO, ALTO mission to LEO, Apollo XI Lunar Module ascent and Starship take-off to LMO are the multifaceted mission scenarios selected to demonstrate the capabilities of conora, resulting in accurate injection into orbit and relatively close estimation of optimized payload masses. The obtained outcomes grow more valuable when considering the small amount of inputs provided, the simplicity of the utilized physical model and the strong assumptions considered. The whole software development process followed a V-model, from requirement definition, passing by the actual implementation, to thorough code testing of each conora’s module. 64 are the number of identified top level requirements, for a verification process elaborated via more than 270 tests, from unit to system level. The entire work was performed in the context of an internship at DLR, at the Institute of Space Systems in Bremen, Germany. / Denna uppsats presenterar conora, en robust mjukvara för optimeringen av flygbanor, via användningen av ortogonala kollokationsmetoder för stigande raketsteg, med fokus på applikationer inom de tidiga faserna av uppdragets utformning. Den förslagna metodiken använder ortogonala kollokationsmetoder, som föredras över konkurrerande metoder för dess robusthet mot fel och osäkerheter i initial gissningen. Detta, tillsammans med lite tillgängliga data kring stigningsprofilen gör att preliminära optimeringar blir komplexa, extremt fallspecifika och därmed också väldigt tidskrävande. Mjukvaran har implementerats för att hantera maximering av nyttolastsmassan på en raket genom att bidra med den krävda flexibiliteten att anpassas till olika uppdragsscenarier, oavsett himlakropp, uppskjutningsplats, farkostsdesign eller given omloppsbana. Korrekt funktionalitet demonstreras genom att replikera nutida uppdrag, genom att förenkla och reducera till den lägsta mängd inmatningsvariabler. Ariane Vs uppstigning till GTO, Elektrons uppskjutning till SSO, ALTO uppdrag till LEO, Apollo XI Lunar Modules uppskjutning och Starships uppskjutning till LMO är de mångfasetterade uppdragsscenarion valda för att demonstrera conoras kapacitet. Resultatet visar på träffsäkra injektioner till omloppsbana och relativt bra uppskattning av optimerad nyttolastsmassa. Resultatet blir mer värdefullt när man tar hänsyn den lilla mängden inmatningsvariabler, enkelheten av de använda fysiska modellerna och de starka antaganden som gjorts. Hela mjukvarans utvecklingsprocess följde en V-modell, från kravskrivning, genom implementationen, till genomgående kodtestning av varje modul i conora. 64 krav på högsta nivå identifierades, för en verifikationsprocess utvecklad via mer än 270 tester, från enhets- till systemnivå. Hela arbetet utfördes inom ett praktikantarbete vid DLR, vid avdelningen för rymdsystem i Bremen, Tyskland.

Predicting noise using computational methods is a common approach in the field of acoustics, offering flexibility and results before a potentially costly installation. This project explores the possibility to calculate the change in noise level emitted from a speaker covered by a capsule, filled with porous material and positioned in two different ways, using the finite element method in the program COMSOL for low to mid frequency bands. The Helmholtz equation is solved in the air medium of the model excluding wave propagation in the solid domain of the capsule where it is present. To replicate the attenuation from porous materials in COMSOL the Delany-BazleyMiki poroacoustics model is used. Comparing the calculation to a control measurement conducted at the Marcus Wallenberg Laboratory, provisional predictions of accuracy is given in groups of configurations and in 1/3-octave bands. Using the available computational power in a common office computer it might be difficult to accurately portray the real-world installation since it might be necessary to alter geometric region, physics or frequency rangedue to runtime issues resulting in deviating results. / Att förutspå ljuddämpning med hjälp av beräkningsmetoder är ett vanligt arbetssätt inom akustik som bidrar till flexibilitet och resultat innan en potentiellt kostsam installation. Det här projektet utforskar möjligheten att beräkna förändringen i ljudnivå från en högtalare som är täckt utav en kapsel fylld utav poröst material. Kapseln är placerad i två olika konfigurationer och finita element metoden används genom programmet comsol för att räkna ut ljudnivåer i låg och medelhöga frekvensband. Helmholtz ekvation löses i luftmediet som omger kapseln och högtalaren och Delany-Bazleys modell för porösa material används, vilken finns tillgänglig i COMSOL. Jämförelsen mellan beräkningen och en kontrollmätning gjord i Marcus Wallenbergs Laboratorium ger indikation på precisionen hos modellen, vilket visas i tersband. Med beräkningskraften hos en konventionell kontorsdator kan det vara svårt att noggrant beskriva den verkliga installationen där avsteg från verkligheten ofta handlar om förenklad geometri och fysik eller förändrat frekvensspann för att förhindra eskalerande problem med programmets körtid vilket leder till avvikande resultat.

Optimizing launcher trajectories is essential for effective mission planning, and specialized software like ASTOS provide an initial, precise overview. However, as launcher development progresses, there is a growing need for the creation of an autonomous flight trajectory software that offers greaterflexibility in adjusting simulation parameters and better represents actual, real-life trajectories. Thisreport introduces an initial version of a comprehensive six-degree-of-freedom launcher trajectory calculation software developed using MATLAB and Simulink. The emphasis is on the development strategy, encompassing discussions on dynamics equations, essential features, and crucial models necessary for accurate simulations. Real-world scenarios often deviate from optimized trajectories, and the software addresses these deviations using sensitivity analysis through Monte Carlosimulations, enabling a thorough examination of uncertainties in input parameters and their impact on trajectories. The article delves into the establishment of the dispersion analysis tool and offers suggestions for further enhancements for both the Simulink model and this dispersion analysis tool. / Optimering av flygbanor är avgörande för effektiv uppdragsplanering, och specialiserad programvara som ASTOS ger en initial, exakt översikt. Men när flygbanans utveckling fortskrider finns det ett växande behov av att skapa en autonom flygbana som erbjuder större flexibilitet när det gäller attjustera simuleringsparametrar och bättre representerar faktiska, verkliga banor. Den här rapporten introducerar en initial version av en omfattande beräkningsprogramvara utvecklad med MATLAB och Simulink för sex frihetsgraders lanseringsbana. Tyngdpunkten ligger på utvecklingsstrategin, som omfattar diskussioner om dynamikekvationer, väsentliga funktioner och avgörande modeller som är nödvändiga för exakta simuleringar. Scenarier i verkligheten avviker ofta från optimerade banor, och programvaran adresserar dessa avvikelser med känslighetsanalys genom Monte Carlo-simuleringar,vilket möjliggör en grundlig undersökning av osäkerheter i inmatningsparametrar och deras påverkan på banor. Rapporten går in i skapandet av spridningsanalysverktyget och erbjuder förslag till ytterligare förbättringar för både Simulink-modellen och detta dispersionsanalysverktyg.

With the electrification of the automotive industry, vehicles tend to be quieter than their internal combustion engine counterparts. Because of this phenomenon, noises and vibrations that were initially imperceptible appear and affect the overall comfort level of the driver and the passengers. It can also lead to structural fatigue witch results in an increase of maintenance and repair costs. In the case of the BlueBus 6m IT3, a disturbance is encountered with the Scroll compressor, placed atop of the driver’s cabin, which supplies the braking system and the suspensions. When running at low speed, it vibrates and enters in resonance with the bus structure. This thesis aims to reduce the resonance between the bus frame and the compressor by focusing on the characteristics frequencies of both systems. The vibrations of the compressor and the bus roof were measured for distinct stiffnesses and positions of the anti-vibration mounts and at the two compressor running speeds: 2000 rpm and 2900 rpm. The Sound Pressure Level (SPL) inside the driver’s cabin and close to the compressor was also acquired to evaluate and compare the different configurations. A reduction of 2 dBA was achieved by increasing the stability of the motor-compressor assembly with a new support made up of wider mounts. The anti-vibration mounts of a shore hardness of 40 Sh were the more efficient with another 2 dBA decrease and a vibration of the roof quartered. A modal analysis confirmed the presence of a coupling between the compressor and the first cavity mode of the bus structure at low speed leading to amplified noise in the bus. Another analysis was performed on a modified compressor structure including the evolutions resulting from the tests. It results in a decoupling between the compressor and the bus frame and reduced bracket vibrations under loads at low speed. / Med elektrifieringen av fordonsindustrin tenderar fordonen att bli tystare än sina motsvarigheter med förbränningsmotorer. På grund av detta fenomen uppstår ljud och vibrationer som från början var omöjliga att uppfatta, vilket påverkar den allmänna komfortnivån för föraren och passagerarna. Det kan också leda till strukturell utmattning, vilket i sin tur leder till ökade underhålls- och reparationskostnader. I fallet med BlueBus 6m IT3 har en störning uppstått i scroll-kompressorn, som är placerad ovanför förarhytten och försörjer bromssystemet och fjädringarna. När den körs med låg hastighet vibrerar den och går i resonans med bussens struktur. Denna avhandling syftar till att minska resonansen mellan bussramen och kompressorn genom att fokusera på de karakteristiska frekvenserna för båda systemen. Vibrationerna från kompressorn och bussens tak mättes för olika styvheter och positioner för antivibrationsfästena och vid de två kompressorhastigheterna: 2000 rpm och 2900 rpm. Ljudtrycksnivån i förarhytten och i närheten av kompressorn mättes också för att utvärdera och jämföra de olika konfigurationerna. En minskning med 2 dBA uppnåddes genom att öka stabiliteten hos motorkompressorenheten med ett nytt stöd som bestod av bredare fasten. De vibrationsdämpande fästena med en shore-hårdhet på 40 Sh var mest effektiva med ytterligare en minskning på 2 dBA och en vibration av taket på en fjärdedel. En modalanalys bekräftade förekomsten av en koppling mellan kompressorn och den första kavitetsmodusen i bussstrukturen vid låga varvtal, vilket ledde till förstärkt buller i bussen. En annan analys utfördes på en modifierad kompressorstruktur som inkluderade de utvecklingar som framkom vid testerna. Det resulterade i en frikoppling mellan kompressorn och bussramen och minskade vibrationer i konsolen under belastning vid låga hastigheter.

<p>Train transportation is a vital part of the transportation system of today anddue to its safe and environmental friendly concept it will be even more impor-tant in the future. The speeds of trains have increased continuously and withhigher speeds the aerodynamic effects become even more important. One aero-dynamic effect that is of vital importance for passengers’ and track workers’safety is slipstream, i.e. the flow that is dragged by the train. Earlier ex-perimental studies have found that for high-speed passenger trains the largestslipstream velocities occur in the wake. Therefore the work in this thesis isdevoted to wake flows. First a test case, a surface-mounted cube, is simulatedto test the analysis methodology that is later applied to a train geometry, theAerodynamic Train Model (ATM). Results on both geometries are comparedwith other studies, which are either numerical or experimental. The comparisonfor the cube between simulated results and other studies is satisfactory, whiledue to a trip wire in the experiment the results for the ATM do not match.The computed flow fields are used to compute the POD and Koopman modes.For the cube this is done in two regions of the flow, one to compare with a priorpublished study Manhart & Wengle (1993) and another covering more of theflow and especially the wake of the cube. For the ATM, a region containing theimportant flow structures is identified in the wake, by looking at instantaneousand fluctuating velocities. To ensure converged POD modes two methods toinvestigate the convergence are proposed, tested and applied. Analysis of themodes enables the identification of the important flow structures. The flowtopologies of the two geometries are very different and the flow structures arealso different, but the same methodology can be applied in both cases. For thesurface-mounted cube, three groups of flow structures are found. First groupis the mean flow and then two kinds of perturbations around the mean flow.The first perturbation is at the edge of the wake, relating to the shear layerbetween the free stream and the disturbed flow. The second perturbation isinside the wake and is the convection of vortices. These groups would then betypical of the separation bubble that exists in the wake of the cube. For theATM the main flow topology consists of two counter rotating vortices. Thiscan be seen in the decomposed modes, which, except for the mean flow, almostonly contain flow structures relating to these vortices.</p> / QC 20100518 / Gröna Tåget

Nowadays, increasing pressure from legislation and customer demands in the automotive industry are forcing manufacturers to produce greener vehicles with lower emissions and fuel consumption.As a result, electrified and hybrid vehicles are a growing popular alternative to traditional internal combustion engines (ICE). The noise from an electric vehicle comes mainly from contact between tyres and road, wind resistance and driveline. The noise emitted from the driveline is for the mostpart related to the gearbox. When developing a driveline, it is a factor of importance to estimate the noise radiating from the gearbox to achieve an acceptable design.Gears are used extensively in the driveline of electric vehicles. As the gears are in mesh, a main intrusive concern is known as gear whine noise. Gear whine noise is an undesired vibroacoustic phenomenon and is likely to originate through the gear contacts and be transferred through themechanical components to the housing where the vibrations are converted into airborne and structure-borne noise. The gear whine noise originates primarily from the excitation coming from transmission error (TE). Transmission error is defined as the difference between the ideal smoothtransfer of motion of a gear and what is in practice due to lack of smoothness.The main objective of this study is to simulate the vibrations generated by the gear whine noise in an electric powertrain line developed by AVL Vicura. The electric transmission used in this study provides only a fixed overall gear ratio, i.e. 9.59, under all operation conditions. It is assumed thatthe system is excited only by the transmission error and the mesh stiffness of the gear contacts. In order to perform NVH analysis under different operating conditions, a multibody dynamics model according to the AVL Excite program has been developed. The dynamic simulations are thencompared with previous experimental measurements provided by AVL Vicura.Two validation criteria have been used to analyse the dynamic behaviour of the AVL Excite model: signal processing using the FFT method and comparison with the experimental measurements.The results from the AVL Excite model show that the FFT criterion is quite successful and all excitation frequencies are properly observed in FFT plots. Nevertheless, when it comes to the second criterion, as long as not all dynamic parameters of the system such as damping or stiffnesscoefficients are provided with certainty in the model, it is too difficult to investigate the accuracy of the AVL Excite model. Another investigation is a numerical design study to analyses how the damping coefficients influence the response. After reducing the damping parameters, the results show that the housing and bearings have the highest influence on the response. If more acceptable results are desired,future studies must be concentrated on these to obtain more acceptable damping values. / För närvarande tvingar ökat tryck från lagstiftning och kundkrav inom bilindustrin tillverkarna attproducera grönare fordon med lägre utsläpp och bränsleförbrukning. Som ett resultat ärelektrifierade och hybridfordon ett växande populärt alternativ till traditionellaförbränningsmotorer (ICE). Bullret från ett elfordon kommer främst från kontakten mellan däckoch väg, vindmotstånd och drivlinan. Bullret från drivlinan är i huvudsak relaterat till växellådan.Vid utveckling av en drivlina är det av betydelse att uppskatta bullret från växellådan för att uppnåen acceptabel design.Utväxlingar används i stor utsträckning i elfordons drivlina. Eftersom kugghjulen är i kontaktuppstår ett huvudproblem som är känt som ett vinande ljud från kugghjulskontakten.Kugghjulsljud är ett oönskat vibro-akustiskt fenomen och uppstår sannolikt på grund avkugghjulkontakterna och överförs via de mekaniska komponenterna till växellådshuset därvibrationerna omvandlas till luftburet och strukturburet ljud. Kugghjulsljudet härstammarhuvudsakligen från exciteringen som kommer från transmissionsfel (TE) i kugghjulskontakten.Överföringsfelet definieras som skillnaden mellan den ideala smidiga rörelseöverföringen hoskugghjulen och rörelsen som sker i verkligheten på grund av ojämnheter.Huvudsyftet med denna studie är att simulera vibrationerna som genereras avkugghjulskontakterna i en elektrisk drivlina utvecklad av AVL Vicura. Den elektriska drivlinan somanvänds i denna studie har endast ett fast utväxlingsförhållande, dvs 9,59, för alladriftsförhållanden. Det antas att systemet är exciterat endast av överföringsfelet och kugghjulensstyvhet i kuggkontakterna. För att kunna utföra NVH-analys under olika driftsförhållanden har enstelkroppsdynamikmodell utvecklats med hjälp av programmet AVL Excite. De dynamiskasimuleringarna jämförs sedan med tidigare experimentella mätningar som tillhandahålls av AVLVicura.Två valideringskriterier har använts för att analysera det dynamiska beteendet hos AVL Excitemodellen:signalbehandling med FFT-metoden och jämförelse med experimentella mätningar.Resultaten från AVL Excite-modellen visar att FFT-kriteriet är ganska framgångsrikt och allaexcitationsfrekvenser observeras korrekt i FFT-diagrammen. Men när det gäller det andra kriteriet,så länge som inte alla dynamiska parametrar i systemet, såsom dämpnings- ellerstyvhetskoefficienter, är tillförlitliga i modellen, är det för svårt att undersöka exaktheten hos AVLExcite-modellen.En annan undersökning som utförts är en numerisk designstudie för att analysera hurdämpningskoefficienterna påverkar responsen. Efter minskning av dämpningsparametrarna visarresultaten att växellådshus och lager har störst inflytande på resultatet. Om mer acceptabla resultatär önskvärda måste framtida studier koncentreras på dessa parametrar för att uppnå mer acceptabladämpningsvärden.

This thesis deals with control aspects of complex hydromechanical transmissions. The overall purpose is to increase the knowledge of important aspects to consider during the development of hydromechanical transmissions to ensure transmission functionality. These include ways of evaluating control strategies in early design stages as well as dynamic properties and control aspects of displacement controllers, which are key components in these systems. Fuel prices and environmental concerns are factors that drive research on propulsion in heavy construction machinery. Hydromechanical transmissions are strong competitors to conventional torque-converter transmissions used in this application today. They offer high efficiency and wide speed/torque conversion ranges, and may easily be converted to hybrids that allow further fuel savings through energy recuperation. One challenge with hydromechanical transmissions is that they offer many different configurations, which in turn makes it important to enable evaluation of control aspects in early design stages. In this thesis, hardware-in-the-loop simulations, which blend hardware tests and standard software-based simulations, are considered to be a suitable method. A multiple-mode transmission applied to a mid-sized construction machine is modelled and evaluated in offline simulations as well as in hardware-in-the-loopsimulations. Hydromechanical transmissions rely on efficient variable pumps/motors with fast, accurate displacement controllers. This thesis studies the dynamic behaviour of the displacement controller in swash-plate axial-piston pumps/motors. A novel control approach in which the displacement is measured with an external sensor is proposed. Performance and limitations of the approach are tested in simulations and in experiments. The experiments showed a significantly improved performance with a controller that is slightly more advanced than a standard proportional controller. The implementation of the controller allows simple tuning and good predictability of the displacement response.

<p>A study of which methods and measures that can be used to reduce fuel consumption and harmful discharges in an airline.</p><p>The study begins with an investigation containing calculations of the differences between estimated fuel consumption calculated by a computer program called Skytrack and actual fuel consumption. Results from this study allows synchronization between actual consumption with calculated consumption. In addition to this methods and configurations to reduce weight and thus weight onboard aircrafts e.g. carpet exchange, lightweight trolleys and water reduction has been created and analysed.</p><p>To bring the thesis to an end, the author has investigated other methods and configurations which TUIfly Nordic is implementing for fuel conservation.</p><p>The thesis results in several conceivable areas for fuel conservation with calculated savings of 830 000 EUR which for the moment is implemented in TUIFly Nordic.</p>

Construction machines, also referred to as engineering vehicles or earth movers, are used in a variety of tasks related to infrastructure development and material handling. While modern construction machines represent a high level of sophistication in several areas, their suspension systems are generally rudimentary or even nonexistent. This leads to unacceptably high vibration levels for the operator, particularly when considering front loaders and dump trucks, which regularly traverse longer distances at reasonably high velocities. To meet future demands on operator comfort and high speed capacity, more refined wheel suspensions will have to be developed. The aim of this thesis is therefore to investigate which factors need to be considered in the fundamental design of suspension systems for wheeled construction machines. The ride dynamics of wheeled construction machines are affected by a number of particular properties specific to this type of vehicle. The pitch inertia is typically high in relation to the mass and wheelbase, which leads to pronounced pitching. The axle loads differ considerably between the loaded and the unloaded condition, necessitating ride height control, and hence the suspension properties may be altered as the vehicle is loaded. Furthermore, the low vertical stiffness of off-road tyres means that changes in the tyre properties will have a large impact on the dynamics of the suspended mass. The impact of these factors has been investigated using analytical models and parameters for a typical wheel loader. Multibody dynamic simulations have also been used to study the effects of suspended axles on the vehicle ride vibrations in more detail. The simulation model has also been compared to measurements performed on a prototype wheel loader with suspended axles. For reasons of manoeuvrability and robustness, many construction machines use articulated frame steering. The dynamic behaviour of articulated vehicles has therefore been examined here, focusing on lateral instabilities in the form of “snaking” and “folding”. A multibody dynamics model has been used to investigate how suspended axles influence the snaking stability of an articulated wheel loader. A remote-controlled, articulated test vehicle in model-scale has also been developed to enable safe and inexpensive practical experiments. The test vehicle is used to study the influence of several vehicle parameters on snaking stability, including suspension, drive configuration and mass distribution. Comparisons are also made with predictions using a simplified linear model. Off-road tyres represent a further complication of construction machine dynamics, since the tyres’ behaviour is typically highly nonlinear and difficult to evaluate in testing due to the size of the tyres. A rolling test rig for large tyres has here been evaluated, showing that the test rig is capable of producing useful data for validating tyre simulation models of varying complexity. The theoretical and experimental studies presented in this thesis contribute to the deeper understanding of a number of aspects of the dynamic behaviour of construction machines. This work therefore provides a basis for the continued development of wheel suspensions for such vehicles. / QC 20110531