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Blockchain is described as having endless theoretical potential. In reality however, it is hard toestablish how blockchain can be utilized and what opportunities blockchain may create. Theunclear future of blockchain constitutes a challenge for many companies. Many large incumbentsare uncertain of how to implement blockchain technology in their organization and are anxiousabout the consequences of the new technology. The purpose of this exploratory study is to evaluateblockchain applications for a district heating company in Stockholm to understand favorable areas,necessary criteria for successful implementation and how blockchain could enable new businessopportunities in the district heating market. To be able to reach the purpose of the thesis aliterature study and an empirical study were performed. The literature study is in the form of anextensive investigation about the areas of blockchain and district heating. The empirical studyincludes 17 interviews, both internal interviews with employees at Stockholm Exergi and externalinterviews conducted with professionals with knowledge about blockchain, district heating and theenergy sector. Furthermore, two workshops, in collaboration with Stockholm Exergi, wereperformed at the end of the thesis to evaluate and prioritize the developed blockchain applications.This thesis proposes 32 blockchain applications within 10 areas in the district heating industry.The applications are categorized after their potential, in three categories; green for the blockchainapplications that are valuable to investigate further, orange for the applications that potentiallycould be interesting to investigate further, and red for the applications that are not interesting toinvestigate further. Some applications focus on solving inefficiencies within district heating andsome on exploiting the benefits of blockchain. Eight applications are categorized with greenprioritization, and thus presented in more detail. To take into account that blockchain probablywill have a greater impact in the future, a future scenario was developed and used in the situationalanalysis for the applications. Furthermore, a framework was developed with the aim to be a toolfor a district heating company to utilize while considering if a blockchain implementation wouldbe beneficial, and if so, in what way. The framework is focused on district heating companies butcan be utilized by other actors as well.Our recommendation for a district heating company in Stockholm is to wait one or two yearswhile staying updated. Especially important for the companies are to stay updated on whether newblockchain standardizations will emerge in the energy sector. However, if a district heatingcompany want to initialize a blockchain project we advise the companies to start a pilot projectthat does not affect the current business model but has the potential to be scaled. Since theblockchain technology enhances collaboration, it is important to consider which partners shouldbe included and how the application can create value for all involved parties. However, due to theuncertainty of the technology, companies need to be well aware of that assumed created value maynot be reached as expected. Furthermore, district heating companies also need to bear in mindthat other parameters, for example additional technologies, policies or infrastructure systems, maybe necessary to implement in order to create value from a blockchain solution. Blockchain beskrivs ofta som något med ändlös teoretisk potential. I verkligheten är det dock svårtatt fastställa hur blockchain kan användas och vilka möjligheter blockchain kan skapa. Den osäkraframtiden för blockchain är en utmaning för många företag att förhålla sig till. Inte minst för storaetablerade företag då blockchain kan användas för att decentralisera en centraliseradmarknadsstruktur. Syftet med denna undersökande studie är att utvärdera blockchainapplikationerför ett fjärrvärmeföretag i Stockholm, för att förstå gynnsamma områden,nödvändiga kriterier vid genomförande och hur blockchain skulle kunna möjliggöra nyaaffärsmöjligheter på fjärrvärmemarknaden. För att uppfylla uppsatsens syfte genomfördes enlitteraturstudie och en empirisk studie. Inom litteraturstudien genomfördes en omfattandeundersökning av blockchain och fjärrvärme. Den empiriska studien bestod av 17 intervjuer, bådeinterna intervjuer med anställda från Stockholm Exergi och externa intervjuer med experter inomblockchain, fjärrvärme och energisektorn. Vidare genomfördes under slutfasen två workshops isamarbete med Stockholm Exergi, för att utvärdera och prioritera de skapade blockchainapplikationerna.Rapporten presenterar 32 blockchain-applikationer inom 10 olika områden inomfjärrvärmeindustrin. Applikationerna är kategoriserade efter sin potential i tre grupper, grön för deapplikationer som kan vara fördelaktiga för ett fjärrvärmeföretag och bör fortsätta undersökas,orange för de applikationer som sannolikt inte skulle vara fördelaktiga och röd för de applikationersom inte är intressanta för ett fjärrvärmeföretag att fortsätta undersöka. Vissa applikationerfokuserar på att lösa de ineffektiviteter som finns för fjärrvärme och vissa på att utnyttja fördelarnamed blockchain. Det åtta applikationer med grön prioritering presenteras mer detaljerat. Ettframtida scenario togs fram för att ta hänsyn till att blockchain sannolikt kommer att ha störrepåverkan i framtiden. Detta används som hjälpmedel när situationsanalysen för applikationernagenomförs. Dessutom utvecklades ett ramverk som har som syfte att vara ett verktyg för ettfjärrvärmeföretag att utnyttja när en blockchain implementering övervägs. Ramverket är inriktatpå fjärrvärmeföretag men kan även användas av andra aktörer.Vår rekommendation till ett fjärrvärmeföretag i Stockholm är att vänta ett eller två år, samtidigtsom de håller sig uppdaterade om marknadsförändringar för blockchain. Särskilt viktigt för ettfjärrvärmeföretag är att hålla sig uppdaterad om huruvida nya blockchain-standardiseringar uppstårinom energisektorn. Om ett fjärrvärmeföretag vill initiera ett blockchain-projekt, rekommenderarvi att starta med ett pilotprojekt som inte påverkar den nuvarande affärsmodellen, men harpotential att skalas. Eftersom blockchain-teknologin möjliggör samarbete är det viktigt attöverväga vilka partners som kan ingå i lösningen och hur applikationen kan skapa värde för allaberörda parter. Företag måste emellertid vara väl medvetna om att det förväntade värdet kanskeinte uppnås på grund av teknologins osäkerhet. Dessutom måste företagen också överväga attandra parametrar, till exempel andra teknologier, politik eller infrastruktur, är nödvändiga, för atten blockchain implementering ska skapa värde.

AbstractA reactor for catalytically oxidizing liquid methanol has been developed for supplying heat to an automotive reformer. In the tests presented in this paper we show that it is possible to catalytically combust liquid methanol by dispersing the methanol and air by a nebulizer over the catalysts. In the experiments we tested several base and noble metals and found that either platinum or palladium was required at the ignition zone. The tests also showed that it was possible to achieve complete combustion when only 25 % of the catalyst bed contained a noble metal.

Using 1281 pedestrian tunnels scattered over Stockholm, Sweden’s capital, we investigate the nature and distribution of graffiti in three types of underpasses (pathways, cycleways, and stairways). Combining crowdsourced data and police records, we compare graffiti levels and geography using fieldwork inspections, regression models, and Geographic Information Systems (GIS). The findings indicate that graffiti recorded to the police is present in only a quarter of the pedestrian tunnels, suggesting that recorded practices are concentrated in specific underpasses. Graffiti is more commonly found in larger tunnels, particularly cycling underpasses. Proximity to metro stations, schools, and the presence of young males in the area are factors linked to graffiti occurrence, although not consistently. These results highlight the complexities of relying on graffiti records for public space management, particularly the challenges professionals face in aligning the maintenance of pedestrian tunnels with urban sustainability goals. QC 20250317

The luminescence efficiency of lanthanide-doped upconversion nanoparticles is of particular importance for their embodiment in biophotonic and photonic applications. Here, we show that the upconversion luminescence of typically used NaYF4:Yb3+30%/Tm3+0.5% nanoparticles can be enhanced by ~240 times through a hierarchical active core/active shell/inert shell (NaYF4:Yb3+30%/Tm3+0.5%)/NaYbF4/NaYF4 design, which involves the use of directed energy migration in the second active shell layer. The resulting active core/active shell/inert shell nanoparticles are determined to be about 11 times brighter than that of well-investigated (NaYF4:Yb3+30%/Tm3+0.5%)/NaYF4 active core/inert shell nanoparticles when excited at ~980 nm. The strategy for enhanced upconversion in Yb3+/Tm3+-codoped NaYF4 nanoparticles through directed energy migration might have implications for other types of lanthanide-doped upconversion nanoparticles.

Abstract This work compares some of the characteristic properties of peat, such as the degree of humification, calorific value and oxygen content of the organic matter, as criteria for selection of peat for liquefaction. It shows the priority of the calorific value over the currently used degree of humification as a criterion.

Abstract Energy system modelling can be used to assess the implications of different scenarios and support improved policymaking. However, access to data is often a barrier to starting energy system modelling in developing countries, thereby causing delays. This article therefore provides data that can be used to create a simple zero order energy system model for Mauritania, which can act as a starting point for further model development and scenario analysis. The data are collected entirely from publicly available and accessible sources, including the websites and databases of international organizations, journal articles, and existing modelling studies. This means that the dataset can be easily updated based on the latest available information or more detailed and accurate local data. These data were also used to calibrate a simple energy system model using the Open Source Energy Modelling System (OSeMOSYS) and two stylized scenarios (Fossil Future and Least Cost ) for 2020-2050. The assumptions used and results of these scenarios are presented in the appendix as an illustrative example of what can be done with these data. This simple model can be adapted and further developed by in-country analysts and academics, providing a platform for future work.

The cryogenic process is used for CO2 purification in oxy-fuel combustion power plant, and multi-stream heat exchanger is one of the most important components. Viscosity and thermal conductivity ar ...

I denna studie har vi undersökt olika bostadsföretags uthyrningspolicy inom Stockholmsområdet samt hur pass lättillgänglig information är om bostadssökningsprocessen via deras hemsidor. Vi vill undersöka om det finns någon skillnad mellan hur bostadsföretag förmedlar sina grundkrav och på vilken nivå dessa ligger för en bostadssökande. Hur påverkar detta samhället och i synnerhet hur påverkar det oss som studenter? Finns det även en skillnad mellan kommunala och privata bostadsföretag i Stockholmsområdet?För att finna svar på frågeställningarna undersökte vi 13 olika privata- och kommunala bostadsföretag; HSB, Ikano Bostad, Wallenstam, Byggvesta, Rikshem, Willhem, HEBA Fastigheter AB, Svenska Bostäder, Stockholmshem, Familjebostäder, Micasa Fastigheter, Stadsholmen samt Stockholms Studentbostäder. Vi studerade hur företagens respektive uthyrningspolicy var utformade på deras hemsidor samt hur lättillgängligt det var att hitta viss väsentlig information som bostadssökande. Detta blev en jämförelse företagen sinsemellan vilket gav oss en överskådlig bild på vad som bör förbättras inom området.Det visade sig finnas en betydlig skillnad mellan privata- och kommunala bostadsföretag där den största skillnaden var att privata bostadsföretag reglerar sina uthyrningspolicy hårdare än vad de kommunala gör. Alla hemsidor var mer eller mindre dåligt utformade gällande tillgänglighet och språkmöjligheter. Vi behandlade även våra studiefrågor utifrån ett hållbarhetsperspektiv då det anses vara betydande för ett fortsatt fungerande samhälle.Avslutningsvis gavs rekommendationer för bostadsföretagen för att förbättra sina hemsidor och policys. Störst vikt bör läggas på att förbättra möjligheten för alla individer på bostadsmarknaden för att få en bostad. Samt att förbättra bostadsföretagens hemsidor i fråga om transparens och språkmöjligheter, för att utveckla bostadsmarknaden ur ett socialt och teknologiskt perspektiv. The main focus in this thesis has been to examine different housing companies rental policy in Stockholm and to review how easily it is to maintain relevant information regarding the leasing process through the companies websites. We want to see if there is any difference between how the housing companies convey their demands and how this affects the person looking for a rental apartment. Furthermore, we want to see how everything above affect the society, especially students. Is there any difference between municipal housing companies and private housing companies in Stockholm?We analysed 13 websites belonging to different housing companies to find answers to our questions. The housing companies involved in the study are: HSB, Ikano Bostad, Wallenstam, Byggvesta, Rikshem, Willhem, HEBA Fastigheter AB, Svenska Bostäder, Stockholmshem, Familjebostäder, Micasa Fastigheter, Stadsholmen and Stockholms Studentbostäder. We studied how the different companies have decided to form their respective rental policy and how easy it is to find relevant information as an applicant. A comparison between the companies became possible with the gained information, the comparison gave us a clear picture of some recommended improvements within the field.It turned out to be a significant difference between the municipal rental companies and the private rental companies, where the private rental companies control their rental policies more strictly than the municipal rental companies. All of the housing companies’ websites were more or less weak in terms of availability and language possibilities. In the study we also covered the perspective of sustainability consider its significance for a further functioning society.In conclusion we provided recommendations for the housing companies in order to improve their rental policies and their websites. In our opinion should most effort be put on improving the opportunities for all individuals on the housing market to receive a residence. The housing companies’ websites should be improved with regard to transparency and language possibilities, to develop the housing market from a social and technologic perspective.

Rotating stall and surge are flow instabilities contributing to the acoustic noise generated in centrifugal compressors at low mass flow rates. Their acoustic generation mechanisms are exposed employing compressible Large Eddy Sim- ulations (LES). The LES data are used for calculating the dominant acoustic sources emerging at low mass flow rates. They give the inhomogeneous char- acter of the Ffowcs Williams and Hawkings (FW-H) wave equation. The blade loading term associated with the unsteady pressure loads developed on solid surfaces (dipole in character) is found to be the major contributor to the aerodynamically generated noise at low mass flow rates. The acoustic source due to the velocity variations and compressibility effects (quadrupole in character) as well as the acoustic source caused by the displacement of the fluid due to the accelerations of the solid surfaces (monopole in character) were found to be not as dominant. We show that the acoustic source associated with surge is generated by the pressure oscillation, which is governed by the tip leakage flow. The vortical structures of rotating stall are interacting with the impeller. These manipulate the flow incidence angles and cause thereby unsteady blade loading towards the discharge. A low-pressure sink between 4 and 6 o’clock causes a halving of the perturbation frequencies at low mass flow rates operat- ing conditions. From two point space-time cross correlation analysis based on circumferential velocity in the diffuser it was found that the rotating stall cell propagation speed increases locally in the low pressure zone under the volute tongue. It was also found that rotating stall can coexist with surge operat- ing condition, but the feature is then seen to operate over a broader frequency interval.