More than a million people die every year due to road traffic accidents globally where one in five serious or fatal accidents occurs during severe weather conditions. Sweden is in the lead of Vision Zero, with the aim of zero casualties due to road traffic, and every year new countries and organisations accept the challenge of saving lives. Early studies have shown that one way of decreasing casualties is to implement floating car data (FCD), which is data obtained from connected road vehicles. One example of such an implementation is to gather knowledge about the current state of the road network enabling targeted winter road maintenance. By implementing FCD for winter road maintenance, besides creating safer roads, savings will be made for the environment by reducing the use of fossil fuels and salt. Since the fleet of road vehicles is going towards being fully autonomous, the volumes of FCD will increase rapidly generating new possibilities for FCD usage. Recent research regarding FCD has mainly focused on traffic flow, speed and route optimisation, together with general methods for FCD mining creating intelligent transport systems. Studies have also been made to cover the gap between road weather information systems (RWIS) monitoring the road condition and thereby improving road weather forecasts. But there is a need for research regarding the implementation of FCD at a level of action, closer to the road users improving winter road maintenance. Presented in this thesis are results gathered in the project Digital Winter, a project initiated by the Swedish Traffic Administration, where FCD regarding tire-to-road friction has been procured for all public roads in Sweden. Results show promising numbers regarding coverage and reliability for implementation of FCD for winter road maintenance follow-up, managing that assigned levels of road friction are achieved. Examples are given for different areas in Sweden where harsh weather conditions are detected and statistics show coverage of FCD both at a daily and hourly level. Multiple suppliers of FCD have been participating in Digital Winter and the measurements presented, show a correlation between suppliers of FCD and methods that today are approved for winter road maintenance follow-up in Sweden. But also that the friction measured using FCD is closer to the true road friction experienced by road users.

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Floating wind turbines are attracting more attention as more than three-quarters of the total offshore technical potential is located in deep water, leading to a growing trend in floating wind farm projects. Consequently, it becomes necessary to develop Floating Offshore Substation (FOSS) to step up voltage and efficiently transmit power to the shore with minimal losses. However, the harsh environment of the sea/ocean imposes significant challenges on the substation’s electrical equipment, which need to be addressed. This research aims to address the challenges with the primary electrical equipment and provide some recommendations and considerations within the framework of offshore wind. An in-depth literature study was conducted to describe the concepts of the floating application mechanically and electrically. The fatigue analysis theory was explained, and concrete examples were presented and evaluated. Moreover, a standard offshore substation design was presented with the primary high-voltage equipment, where the offshore considerations were highlighted based on the existing standards. Ultimately, a communication channel between the windfarm developer Vattenfall AB and the manufacturer Siemens Energy was established to enable cooperation between industries to discuss the topic, and obtain results from experts’ opinions and experiences. The literature study found that the semi-submersible platform structure performs better than other concepts in different water depths and environmental conditions. The electrical equipment onboard experiences similar equivalent damage regardless of the weight. Furthermore, some specific technical challenges and recommendations on the high-voltage equipment were identified through the mentioned cooperation. For instance, oil-immersed transformers and shunt reactors have better potential than dry-type or gas-insulated types, despite decaying the oil dielectric property due to the vibrations. High-voltage Gas Insulated Switchgear (GIS) is a preferable choice to the air-insulated types. Lastly, there is a lack of standards regarding equipment testing for floating application. Identifying a valid methodology to determine the equipment’s fatigue load capability, and alternatives to the shake table test is a necessity to make this substation happen. / Flytande vindkraftverk lockar alltmer uppmärksamhet då över tre fjärdedelar av det totala tekniska potentialen för havsbaserad vindkraft finns i djupt vatten, vilket leder till en växande trend av projekt med flytande vindparker. Följaktligen blir det nödvändigt att utveckla FOSS för att höja spänningen och effektivt överföra energi till land med minimala förluster. Dock medför den hårda havsmiljön betydande utmaningar för den elektriska utrustningen på stationen, vilka behöver hanteras. Denna forskning syftar till att identifiera utmaningarna med den primära elektriska utrustningen och ge rekommendationer och överväganden inom ramen för havsbaserad vindkraft. En grundlig litteraturstudie genomfördes för att beskriva koncepten för flytande tillämpningar både mekaniskt och elektriskt. Utmattningsanalysteorin förklarades och konkreta exempel presenterades och utvärderades. Dessutom presenterades en standarddesign för havsbaserad station med den primära högspänningsutrustningen, där havsrelaterade överväganden betonades baserat på befintliga standarder. Slutligen etablerades en kommunikationskanal mellan utvecklaren Vattenfall AB och tillverkaren Siemens Energy för att möjliggöra samarbete mellan industrierna för att diskutera ämnet och få resultat från experternas åsikter och erfarenheter. Litteraturstudien visade att den halvsumpade designen presterar bättre än andra koncept i olika vattendjup och miljöförhållanden. Den elektriska utrustningen ombord upplever liknande ekvivalenta krafter oavsett vikten. Vidare identifierades vissa specifika tekniska utmaningar och rekommendationer för högspänningsutrustningen genom det nämnda samarbetet. Till exempel har oljeisolerade transformatorer och strömspolar bättre potential än torr- eller gasisolerade typer, trots att oljans dielektriska egenskaper försämras på grund av vibrationer. Högspännings-GIS är ett föredraget val jämfört med luftisolerade typer. Slutligen finns det brist på standarder för utrustningstestning för flytande tillämpningar. Att identifiera en giltig metodik för att bestämma utrustningens förmåga att hantera belastning vid utmattning, samt alternativ till shake table-test, är nödvändigt för att genomföra denna flytande havbaserad station.

<p>This thesis is the result of several experiments designed to probe the low temperature physics underlying the 1D-Ising-like behaviour of chains of spins in the structure of Cobalt Niobate, CoNb2O6. A collection of prior work has been done by several groups prior to this, focusing on mapping the phase diagram above 0.5K. Interest in this material was renewed recently based upon theoretical work and experimental confirmation of the unique structure of the spins in the system. The bulk of this work was done at temperatures below the previously investigated range to probe the unique properties of this system.</p> <p>The material was grown at McMaster University using the optical floating zone technique from oxide powders. The crystal was examined and oriented using single crystal and Laue diffraction and was cut for use in further experiments. Squid magnetometry was used to confirm the material properties and phase transition temperatures, and was compared to literature values.</p> <p>Heat capacity measurements were performed locally down to 2K, and by collaborators at Waterloo in the range from 330mK to 1K. The heat capacity measurement confirmed the 2.9K transition and explored the relaxation time of the material. Cobalt niobate was found to have an exceptionally long relaxation time at low temperatures indicating strong spin-spin interactions. A sharp transition with zero applied field was found to become a broad, smooth feature at 2.9K when a small field was applied.</p> <p>We performed muSR measurements in zero, longitudinal and transverse field. The muSR results confirmed the long relaxation time found by the heat capacity measurements, which may reflect the coupling of the spin system to the lattice. Additionally, the material was never seen to statically order in zero or longitudinal field down to 700mK and up to 1T. The material was found to behave dynamically throughout all the field ranges.</p> / Master of Science (MSc)

The ocean has tremendous potential in terms of energy generation, and wave energy is especially promising. However, wave energy technology is still non-commercial. Along with ambitious renewable energy targets and investments, much is happening within the field and the wave energy converter developers CorPower Ocean intend to have their technology proven in the upcoming years. This study aims at investigating the value of commercial wave energy in an energy system. This is fulfilled by the possibilities of achieving 24/7 Carbon-free Energy with the wave energy technology from CorPower Ocean at the stage of commercialization. An energy system is modeled with wave energy, floating offshore wind energy, lithium-ion battery storage and the Portuguese national grid, supplying Northvolt’s and Galp’s future lithium conversion facility in Portugal. Different system configurations are compared based on three Key Performance Indicators: 24/7 Carbon-free Energy performance, system emission, and cost for the electricity consumer. In addition, a review of available financial support mechanisms for renewable energy technologies and especially wave energy is done to understand how such mechanisms can affect the economic feasibility of the energy system modeled. The wave energy technology from CorPower Ocean shows to have a high power output and 24/7 carbon-free Energy performance in this study. Although a combination of wave and floating offshore wind energy better ensure energy security with generation profiles that peak at different times, the modeling shows that a system with wave energy alone is preferred for supplying the facility with electricity both from an environmental and economic perspective. The economic feasibility of Lithium-ion battery storage in the system is uncertain and to achieve 24/7 Carbon-free Energy supply of the facility a longer duration storage solution is needed. The price for wave energy in this study is higher than for other commercial renewable energy technologies such as solar PV. However, based on the available financial support structures from governments and other stakeholders, wave energy technology has the potential to be competitive as soon as the technology is proven. / Energigenerering från våra hav har stor potential, inte minst från vågkraft. Trots att vågkraftstekniken ännu inte har nått ett kommersiellt stadie händer det mycket inom området i takt med fler ambitiösa miljökrav och investeringar. CorPower Ocean utvecklar vågkraftsteknik och planerar att ha sin teknik bevisad inom några år. Den här studien syftar till att undersöka värdet av kommersiell vågkraft, vilket uppfylls genom möjligheterna till förnybar el 24 timmar om dygnet med CorPower Ocean’s vågenergiomvandlare. Ett energisystem modelleras med vågkraft, flytande vindkraft, litium-jon batterier och det portugisiska elnätet för att försörja Northvolts och Galps planerade anläggning för litiumkonvertering i Portugal. Olika systemkonfigurationer är jämförda utifrån tre parametrar: 24/7 förnybar el prestation, systemutsläpp och elkostnad för konsumenten. I tillägg utförs en studie om vilka finansiella supportmekanismer som finns för hållbar energiteknik och speciellt för utvecklingen av vågkraft. Detta för att få insikt i om vågkraft kan få finansiellt stöd och konkurrera med andra förnybara energitekniker. Studien visar att vågkraftstekniken presenterar bra utifrån de tre parametrarna. Trots att en kombination av våg och flytande vindkraft ger bättre elsäkerhet med alternerande produktionskurvor visar modelleringen att ett system med endast vågkraft är att föredra både från ett ekonomiskt och ett miljöperspektiv. En investering av litium-jon batterier i energisystemet är tveksam och för att uppnå förnybar elförsörjning av anläggningen 24 timmar om dygnet krävs en energilagringsteknik som möjliggör lagring över längre perioder. Priset för vågkraft i studien är högre än för andra kommersiella förnybara energitekniker så som solpaneler. Baserat på det finansiella stöd som finns från myndigheter och andra intressenter så är det möjligt för vågkraften att bli konkurrenskraftig så fort tekniken är bevisad.

Floating solar technology is relatively new, and it comes with its own set of challenges and opportunities. This master thesis focuses on understanding how Floating Photovoltaic (FPV) projects perform compared to Ground-Based Photovoltaic (GPV) projects, in specific weather conditions. The following work is based on a case study: a floating power plant run by Akuo Energy, where sensors have been installed in order to measure the evolution of relevant physical and weather parameters on-site. Akuo Energy is a French independent renewable energy producer and developer founded in 2007. The company specializes in the development, financing, construction, and operation of renewable energy projects, including wind, solar and storage power plants. It is committed to producing clean, affordable, and reliable energy while promoting sustainable development and supporting local communities. The thesis is conducted within the Solar Technology Team, which centralizes the solar expertise of the company and implements innovative technologies to improve their Photovoltaic (PV) projects’ performances. As the number of FPV projects increases, the team raised the need for better evaluation of their performance compared to a standard GPV project, in terms of output power and energy yield. As it appears in the literature, FPV installations can differ from GPV, due to different operating conditions: power plant designs, module cooling, weather conditions, or degradation rates. These parameters need to be taken into account in the expected energy yield analysis, especially module cooling, since operating temperature has a proved impact on module efficiency. Today, technological and economic considerations on FPV specific design are therefore essential. However, the main solar projects development software PVsyst used at Akuo Energy does not include a default floating solar library. Experimental measurements are a good starting point for understanding how the numerical model needs to evolve to adapt to the FPV system. By examining a practical case and processing historical data, insights on FPV systems and how weather affects their efficiency can be provided. The objective of this thesis is then to better model the FPV array thermal losses due to the cooling effect and better estimate the yield for future Akuo Energy FPV projects during the development phase. / Flytande solteknik är relativt ny och kommer med sina egna utmaningar och möjligheter. Denna masteruppsats fokuserar på att förstå hur FPV-projekt presterar jämfört med GPV-projekt, under specifika väderförhållanden. Följande arbete är baserat på en fallstudie: ett flytande kraftverk som drivs av Akuo Energy, där sensorer har installerats för att mäta utvecklingen av relevanta fysiska parametrar och väderparametrar på plats. Akuo Energy är en fransk oberoende producent och utvecklare av förnybar energi som grundades 2007. Företaget är specialiserat på utveckling, finansiering, konstruktion och drift av projekt för förnybar energi, inklusive vind-, sol- och lagringskraftverk. Det är engagerat i att producera ren, prisvärd och pålitlig energi samtidigt som man främjar hållbar utveckling och stödjer lokala samhällen. Examensarbetet genomförs inom Solar Technology Team, som centraliserar företagets solexpertis och implementerar innovativa teknologier för att förbättraderas PV-projekts prestanda. När antalet FPV-projekt ökar, tog teamet upp behovet av bättre utvärdering av deras prestanda jämfört med ett standard GPV-projekt, vad gäller uteffekt och energiutbyte. Som det framgår av litteraturen kan FPV-installationer skilja sig från GPV på grund av olika driftsförhållanden: kraftverkskonstruktioner, modulkylning, väderförhållanden, eller nedbrytningshastigheter. Dessa parametrar måste beaktas ta hänsyn till den förväntade energiutbytesanalysen, särskilt modulkylning, eftersom driftstemperaturen har en bevisad inverkan på modulens effektivitet. Idag är därför tekniska och ekonomiska överväganden om FPV specifik design viktiga. Emellertid innehåller den huvudsakliga utvecklingsmjukvaran PVsyst för solenergiprojekt som används på Akuo Energy inte ett flytande solcellsbibliotek som standard. Experimentella mätningar är en bra utgångspunkt för att förstå hur den numeriska modellen behöver utvecklas för att anpassa sig till FPV-systemet. Genom att undersöka ett praktiskt fall och bearbeta historiska data kan insikter om FPV-system och hur vädret påverkar deras effektivitet ges. Syftet med denna avhandling är sedan att bättre modellera FPV-matrisens termiska förluster på grund av kyleffekten och bättre uppskatta avkastningen för framtida Akuo Energy FPV-projekt under utvecklingsfasen.

Multiline anchors are a novel way to reduce the cost of arrays of floating offshore wind turbines (FOWTs), but their behavior is not yet fully understood. Through metocean characterization and dynamic simulations, this thesis investigates the effects of wind-wave misalignment on multiline anchor systems. Four coastal U.S. sites are characterized in order to develop IEC design load cases (DLCs) and analyze real-world misaligned conditions. Stonewall Bank, Oregon showed the highest 500-year extreme wave height, at 16.6 m, while Virginia Beach, Virginia showed the highest 500-year wind speed, at 56.8 m/s. Misalignment probability distributions, at all sites, are found to converge towards zero (aligned conditions) and become less variable as wind speed increases. This indicates that high misalignment angles are unlikely at high wind speeds. A simulation parameter study, spanning a range of wave directions, misalignment angles, and DLCs, is run in OpenFAST to explore how misalignment affects multiline anchor loading. The simulated anchor is connected to three IEA 15 MW FOWT models via a taut mooring system. The force on the multiline anchor is calculated by summing the three tension vectors from the mooring lines. The mean direction of this force is found to align closely with the wind; each mean is within 5.5° of the wind direction. Higher misalignment angles cause increases to the amount of directional variation about this mean. The magnitude of the multiline force is also examined. Mean force level is found to be nearly unaffected by misalignment. However, maximum force decreases significantly as misalignment angle increases, dropping as much as 23.3% in extreme conditions. This confirms current anchor design practice, which treats aligned metocean conditions as the peak load an anchor experiences. Standard deviation of multiline force also decreases with misalignment. The operational load case, DLC 1.6, shows a slight trend towards this, but the extreme case, SLC, shows a more pronounced drop of 32.4%. This suggests that anchor cyclic loading analyses could benefit from considering misalignment. Doing so could lead to lower estimates of the cyclic loading amplitudes that anchor designs must withstand, thus leading to smaller, cheaper anchors.

Docking maneuvers are a relevant part of the modern space mission, requiring precision and safety to ensure the success of the overall mission. This thesis proposes using a non-linear Model Predictive Control (MPC) as a controller with various constraints to ensure safe docking maneuvers for a satellite. This was done in MATLAB using as a model for the satellite the Sliders used by the Robotics Lab at Luleå University of Technology (LTU). The controller was tested first on the MATLAB model and then briefly on hardware.The main objective of this thesis is to develop and implement an MPC-based control strategy to achieve safe docking maneuvers between two satellites. Great attention has been paid to implementing constraints, such as collision avoidance, and hardware constraints, such as thrust limits, to ensure the safety and reliability of the process.Through the MATLAB simulations, it was possible to indicate that the introduced constraints contribute significantly to the safe execution of docking maneuvers, preventing collisions, andoptimizing fuel usage. The controller successfully adapts to unforeseen disturbances and uncertainties in real-time, showcasing its robustness and reliability in dynamic space environments.The hardware simulations have shown that the controller operates as expected but needs further tuning to adapt to the hardware uncertainties.In conclusion, this thesis comprehensively explores MPC-based control strategies with constraints for space docking maneuvers. The positive results underscore this approach’s potential to ensure the safety and reliability of future space missions, opening avenues for further research and application in autonomous space systems.