This report presents the result of a Master thesis course done at the Machine Design department at KTH. The thesis was written at the company Svea Teknik in collaboration with the tunnel boring machine manufacturer Atlas Copco. The high longitudinal force needed when the Remote Vein Miner is boring is achieved by the friction when clamping the machine between the tunnels ceiling and ground using hydraulic cylinders mounted on the top and bottom of the machine. A new generation of machines doesn’t allow for the bottom cylinders to be fitted on the machine. The pair of continuous tracks used to propel the machine must bear these loads but the tracks aren’t strong enough to alone support the weight of the boring machine. This creates the need for an unloading system which unloads the inner wheels of the track so they don’t fail. Concepts were generated using a morphological matrix with the load sharing unit broken down to sub functions with several solutions paired to each. The iterative process led to nine concepts, where two proved more promising than the others when they were subjected to a Pugh’s evaluation matrix. The two concepts were developed further where a feasibility analysis indicated that only one concept was feasible with the dimensions given in a CAD model together with the load provided by Atlas Copco. The remaining concept is based on hydraulic cylinders lifting the inner wheels of the track to unload them while the machine is boring. The machine is then resting on a skid mounted inside the track. A CAD model was made of the new concept and the new components strength was analyzed using FEM-models. / I denna uppsats presenteras resultatet av ett examensarbete för masterprogrammet Maskinkonstruktion på KTH. Arbetet utfördes på förtaget Svea Teknik tillsammans med tunnelborrmaskintillverkaren Atlas Copco. De stora longitudinella krafterna som krävs när tunnelborrmaskiner borrar erhålls med hjälp av hydraulcylindrar monterade både på ovan- och undersidan av maskinen som klämmer fast maskinen mellan tunnelns golv och tak. En ny generation maskiner från Atlas Copco tillåter inte hydraulcylindrar monterade framtill på undersidan av maskinen. Istället tar de båda bandenheterna som är avsedd att driva maskinen framåt upp dessa krafter. Bandenheterna är inte tillräckligt starka för dessa laster utan en avlastningslösning för hjulen inne i bandenheten behövs. Problemet delades upp i subfunktioner som sattes in i en morfologisk matris för att generera koncept. Den iterativa processen ledde till nio koncept där två av dem visades mest lovade efter en konceptutvärdering med hjälp av en Pugh’s matris. De båda koncepten arbetades vidare till en mer detaljerad nivå där en rimlighetsanalys visade att endast ett koncept var fysiskt möjligt att applicera med de givna begräsningarna som gavs av utrymmet i den givna CAD-modellen tillsammans med de givna lasterna. Det kvarstående konceptet baseras på hydrauliska kolvar som monteras på hjulen i bandenheten. Dessa förflyttar hjulen uppåt tills de inte är i kontakt med bandenhetens kedja längre. Kedjan vilar då på en stödstruktur som är stark nog för lasterna. En CAD-modell gjordes på konceptet och de nya komponenternas hållfasthet analyserades med hjälp av FEM-modeller.

This thesis project aims to repurpose an abandoned railway tunnel in Eriksdalslunden, Stockholm into an experimental activity/farming center for the purpose of teaching people of all ages different farming methods. The learning center implements exciting farming techniques such as aquaponics, where plants get their nutrients from live fish.  This center also teaches about the new technologies that make it possible to grow plants beneath the earth´s surface. These technologies harness the benefits of the sun into a concentrated form and then leads it deep underground. Repurposing unused underground spaces such as this can help develop our cities in a more efficient way. / Detta avhandlingsprojekt syftar till att omarbeta enövergiven järnvägstunnel i Eriksdalslunden,Stockholm till en experimentell verksamhet / jordbrukscentrum för att undervisa människor i alla åldrar olika odlingsmetoder. Inlärningscentralen implementerar spännande odlingstekniker som aquaponics, där växter får sinanäringsämnen från levande fisk.Detta centrum lär också om den nya tekniken som gör det möjligt att växa växter under jordens yta. Dessa tekniker utnyttjar solens fördelar i en koncentrerad form och leder sedan den djupt under jorden. Repurposing oanvända underjordiska utrymmen som detta kan hjälpa till att utveckla våra städer på ett mer effektivt sätt.

The McMurdo Dry Valley region is the largest ice-free area of Antarctica. Harsh abiotic conditions of the polar desert ecosystem, including extreme cold, aridity, and limited nutrient availability select for unique taxa. The comparatively simple terrestrial ecosystem is well-suited for investigating edaphic influences on microbial presence, activity, and community structuring. The Dry Valleys are viewed as a useful analog for Mars astrobiology investigations. However, most biotic investigations have been focused on lower elevations, where an understanding of edaphic effects on microbial communities within its generally more favorable conditions has emerged. Transiently wetted Dry Valley water tracks may be analogous to recurring slope lineae on Mars. Dry permafrost is rare on Earth, and unique to high-elevation Antarctica soils, but is ubiquitous on Mars. Identifying if abiotic properties known to structure microbial communities within low elevation soils holds true for water tracks and dry permafrost is not known. My dissertation investigates edaphic effects on microbial communities within water track soils and dry permafrost. First, I review the ecological effects of transient wetting within hyperarid environments of the Atacama Desert of Chile and the Dry Valleys of Antarctica and apply the findings to possible habitability of modern and early (i.e., ~3.5 bya) Mars surface environments. I show that deliquescent hygroscopic salts facilitate biological response where little or no biotic activity would occur otherwise, yet the salts can also inhibit life. Transient wetting alone may also not be enough to support life. Secondly, I examine bacterial community composition, richness, and diversity on and off water track soils in Taylor Valley and show they are significantly different in composition, which likely influence ecosystem functioning. Salinity is shown as the best predictor of composition. Third, I examine a bacterial community from a Beacon Valley water track, which we believe is among the highest, driest, and coldest soils on Earth that still experiences brief seasonal wetting. I show a small but diverse community is present, with some viable cells, yet no detectable RNA is expressed by the community when tested within a suite of simulated Martin soils. Finally, I examine bacterial and fungal communities in dry permafrost of Arena Valley. I show a strikingly minimal microbial community severely restricted by the extreme cold, oligotrophy, and aridity. Several abundant taxa are related to those within maritime, costal, and endolithic habitats, indicating that they are foreign inoculum. The communities appear to be inactive to such a degree that they are not meaningfully structured by the broad suite of measured abiotic properties. Dry permafrost soils and water track environments are extremely challenging habitats, but they are generally more favorable than conditions observed on Mars. My research has important ecological value for investigating terrestrial thresholds of microbial habitability on Earth and for Mars astrobiology investigations.

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I detta arbete undersöks lyssnares förväntningar på olika musikframträdanden. Arbetet består av en enkät med 46 enkätsvar som tar in ett publikperspektiv, en intervju med en aktiv musikproducent, samt ett genomförande av examenskonserten Friden&amp;Friends. Bakgrunden till arbetet är mina personliga frågeställningar om hur viktigt andra tycker att det är att musiken låter likadant live som den gör i studioversionen, samt om förväntningarna skiljer sig åt mellan genrer och mellan personer som är verksamma inom musik eller inte. Mina resultat visar att det inte spelar någon större roll för de flesta om det låter likadant eller inte, och att det finns många andra faktorer som har betydelse för en lyckad livekonsert. I min examenskonsert Friden&amp;Friends använde jag inte backing tracks, utan låtarna fick stå för sig själva med de medverkande musiker som var där. Det beslutet tog jag efter att ha tagit del av enkätsvaren och i samråd med musikerna. I slutet av arbetet beskriver jag hur olika tillvägagångssätt kan utveckla mitt konstnärliga uttryck, bland annat att musiken bara är en del av upplevelsen och att min personlighet och mina tankar om examenskonserten lyser igenom allt jag gör. / <p>I medföljande video finns utvalda delar av examenskonserten Friden&amp;Friends. Lista på medverkande musiker och all musik som framfördes finns med i eftertexterna. </p>

The understanding of rail vehicle steady-state and dynamic curving has increased substantially in the last few years. Contemporary curving models include such nonlinear effects as two-point contact, creep force saturation, and rail flexibility. The usual approximation concerning the contact geometry is that the Iocalized wheel and rail curvatures at the center of the contact patch are constant throughout the contact patch. This approximation allows computation of contact stresses using Hertzian theory, and it allows the computation of contact patch forces using one of Kalker’s theories. In vehicle curving, contact usually occurs at or near the wheel flange, where the wheel/rail contact geometry is non·Hertzian. Furthermore, after being in service for some time, the wheel and rail profiles provide non·Hertzian geometry due to wear. Both of these effects tend to invalidate the assumption of Hertzian contact geometry in the contact region. This work uses a generic wheelset model which is the basic component of any rail vehicle model. The wheel/rail interaction is modelled using the finite element method. The wheel is generated as a surface of revolution of its tread profile, and the rail is generated as an extrusion of the rail head profile. Three—dimensional contact elements are used to characterize the wheel/rail interface. A simple stick/slip friction model is used wherein relative motion is permitted if the tangential force exceeds the adhesion limit, and no relative motion occurs otherwise. The results show that the finite element method was successfully used to solve the static contact problem. Both Hertzian and non-Hertzian contact problems were anaIyzed correctly. However, the application of the finite element method to the rolling contact problem was not completely successful. The finite element method results for tangential contact forces were about 25 percent lower than forces predicted by Kalker’s theory. Recommendations for extending the analysis to solve the rolling contact problem are made. The report includes a derivation of the wheelset steadystate equations of motion, as well as a solution algorithm for the nonlinear, algebraic equations. / Master of Science / incomplete_metadata

The International Civil Aviation Organization (ICAO) proposed to introduce new operational strategies across the North Atlantic (NAT) airspace. This includes Minimum Navigation Performance Specifications (MNPS) airspace to increase the capacity and efficiency of the North Atlantic Organized Track System (NAT OTS). A numerical integration and simulation model called North Atlantic Simulation and Modeling (NATSAM) is developed to study the effects of these new strategies on NAT system performance. The model is capable of investigating the effects of implementing different operational policies and strategies proposed by ICAO such as Reduced Lateral Separation Minimum (RLatSM), NAT Region Data link mandate (DLM), Reduced Longitudinal Separation Minimum (RLongSM), cruise-climb profiles, variable Mach number profiles, step-climbs and other operational concepts to be studied by the ICAO. NATSAM models the individual flight performance using the Base of Aircraft Data (BADA) 3.9 model to calculate the flight profiles and fuel burn. The model employs simple heuristics to execute flight track assignment in the organized track system for each scenario. Detailed outputs and also aggregated outputs are provided by the model from which various key performance indicators (KPI) can be derived to assess the performance of the system. / Master of Science

Ph. D.