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Från förorenad mark – till en grön framtid - Naturbaserade lösningar i stadsmiljö
No full textDenna rapport undersöker hur naturbaserade lösningar kan bidra till förbättrad markkvalitet i
stadsmiljö, med fokus på Göteborg. På grund av stadens industriella historia är flera stadsdelar
idag förorenade med skadliga ämnen, vilket försvårar stadsutvecklingen. Under de senaste åren
har behovet av långsiktigt hållbara behandlingsmetoder ökat och år 2021 släppte Europeiska
kommissionen en ny markstrategi. Markstrategin menar att all mark ska vara frisk år 2050 och att
naturbaserade lösningar behöver användas som ett verktyg. Trots detta finns det fortfarande
begränsad information kring hur naturbaserade lösningar, med koppling till markkvalitet, kan
tillämpas. Syftet med studien är att sammanställa information om hur naturbaserade lösningar kan
användas för en förbättrad markhälsa i staden, samt täcka de kunskapsluckor som har identifierats.
För att uppnå detta har en kunskapssammanställning tagits fram, där resultatet består av en tydligt
strukturerad tabell som beskriver fem naturbaserade lösningars potential och begränsningar.
Tabellen ger en tydlig vägledning kring metodernas lämplighet vid tillämpning. Utöver detta har
tre intervjuer genomförts för att belysa ämnet utifrån flera perspektiv, med hjälp av relevanta
aktörer. Slutligen utfördes en fallstudie av en fiktiv park, för att visa hur projektets
kunskapssammanställning kan bidra till en verklig tillämpning, samt hur detta hade kunnat se ut.
Rapporten visar att naturbaserade lösningar, med koppling till markkvalitet, har stor potential men
att osäkerheten i effektivitet och de nödvändiga platsförhållandena kan försvåra metodens
användning. För att möjliggöra en bredare implementering i framtida saneringsprojekt krävs
fortsatt forskning, fler referensprojekt men framför allt ett större engagemang från involverade
aktörer. Även tidig beaktning av markförhållandena i planeringsprocessen kan anses vara
avgörande
En modulär vindkraftverksmodell för utbildning och experimentella tillämpningar i Chalmers vindtunnel
No full textDetta projekt presenterar utveckling, konstruktion och utvärdering av ett modellskaligt horisontalaxlat vindkraftverk, särskilt anpassat för experimentella studier i Chalmers vindtunnel. Projektets huvudsyfte var att utveckla en tillförlitlig och modulär prototyp som kan generera experimentella data kring kraftverkets prestanda under varierande vindförhållanden, bladvinklar och elektriska belastningar.
Utvecklingen följde en iterativ produktutvecklingsprocess, där teoretiska beräkningar, aerodynamiska simuleringar, hållfasthetsanalyser och vindtunneltester ingick. En central egenskap hos den färdiga modellen är dess justerbara bladvinkelmekanism, vilken möjliggör synkroniserad vinkelstyrning genom ett internt kugghjulssystem. Komponenterna tillverkades med en kombination av SLA- och extruderande 3D-utskrift samt svarvning
och fräsning, vilket säkerställer både mekanisk hållfasthet och dimensionsnoggrannhet.
Kalibrering av den valda motorn, använd som generator, bekräftade dess lämplighet inom det avsedda arbetsområdet. Vindtunnelmätningar visade att modellen kan återge realistiska prestandakurvor, inklusive effektuttag och verkningsgrad (Cp), under olika driftförhållanden. Den högsta uppmätta effekten på 1,8 W vid nominell vindhastighet erhölls vid en bladvinkel på 60° och en elektrisk belastning på 26,3 Ω, inom ramen för de testade
konfigurationerna.
Prototypen lämpar sig väl för framtida forskning och utbildning. Den utgör en värdefull plattform för studier av rotorers aerodynamik, strukturella laster och reglerstrategier, samt kan fungera som grund för jämförande analyser mellan olika kraftverksarkitekturer
A learning from demonstration approach for DORA: A Dexterous Robot Assistant
No full textMobile manipulators are robotic systems with a mobile base and a robotic arm. They are increasingly useful for tasks performed in unstructured and dynamic environments. This project enhances the capabilities of a mobile manipulator called DORA, by incorporating imitation learning.
Preliminary experiments are conducted to assess DORA’s existing capabilities in both simulated and real-world environments. These tests confirm that DORA can successfully execute tasks based on its current functionality.
Imitation learning, specifically Learning from Demonstration (LfD), enables DORA to learn new tasks by replicating the movements of a human demonstrator. A teleoperation setup, consisting of an AprilTag and MoCap gloves, is used to collect four dimensional data capturing the robot’s 3D position and open/close state of the gripper.
The collected 4D data is used to train an imitation learning algorithm in a simulation environment. The comparison between the Dynamic Time Warping (DTW) and Fréchet distance (FD) scores for the training and test data shows that the trained imitation learning model generalizes well to the demonstrated motion patterns. In conclusion, this thesis lays a solid foundation for further improving DORA’s dexterity through imitation learning
Kommunikationskanal för social verksamhet
No full textThis report presents the design, implementation and evaluation of a push notification system integrated into an existing Unity-based mobile application for a youth center. An agile, sprint-driven methodology guided the work, which involved selecting Firebase Cloud Messaging (FCM) for cross-platform notification delivery, developing a Node.js/TypeScript REST API with Express and a PostgreSQL backend containerized via Docker, and creating an administrative web interface to trigger notifications. Key challenges addressed include secure token handling through FCM topics, platform-specific configuration in Unity for Android and iOS, and maintaining a reliable message history within the app. The system was validated through emulator and real-device tests (Google Play Console, Apple TestFlight) and user feedback sessions. The resulting solution offers a robust, scalable communication channel balancing technical functionality and usability
Enhanced CA15-3 Production Using Microcarrier-Based ZR75-1 Cultures
No full textFujirebio Diagnostics AB (FDAB) produce tumour markers for clinical diagnostics, including CA15-3, which is used to monitor breast cancer. Currently, CA15-3 is produced using ZR75-1 cells cultured in roller flasks, a manual, time-consuming
process with limited scalability. To improve this, there is growing interest in transitioning to bioreactor-based systems using microcarriers, which offer higher surface area-to-volume ratios suitable for adherent cell growth. This thesis explores whether microcarrier-based cultivation can improve CA15-3 production and serve as a scalable alternative to the roller bottle process. ZR75-1 cells were cultured on various microcarriers (CultiSpher G, Corning Enhanced Attachment, BioNOC II, and Fibra-Cel) in spinner flasks, and antigen levels (CA15-3, CA125, and CEA) were monitored. Attachment efficiency, cell density, and viability were also assessed. CultiSpher G showed the best performance and was used in bioreactor trials with perfusion. Peak productivity in spinner cultures reached 23 kU/L/day, about 167% higher than estimated roller flask levels. In contrast, bioreactor productivity reached 3.7 kU/L/day but was limited by premature perfusion and cell density loss. These findings demonstrate that microcarrier cultures, particularly with CultiSpher G, can significantly enhance CA15-3 production and have strong potential for scale-up. Further optimization of attachment, perfusion timing, and bioreactor conditions is needed. Transitioning to such systems could reduce manual handling at FDAB and improve process efficiency for future antigen production
Active Transformer Flux Balancing for a PSFB-DAB Converter
No full textAbstract
This thesis investigates the implementation of active flux balancing on a planar transformer within a PSFB-DAB converter system. This is used to mitigate magnetizing flux and prevent transformer core saturation. The approach starts with the creation of a state-space model of the transformer, followed by the development of two PI-based controllers including a flux balancing controller and a DC offset controller. A hybrid control approach was also briefly investigated. The worst-case operating scenario for the system was examined considering component variations, temperature effects, changes in primary and secondary voltages and phase shifts. This was then used to evaluate the worst-case operating conditions to determine the
maximum offset the controller could handle while still preventing saturation. The results show that the converter can handle a maximum voltage step of 4.9 V for the worst case operating condition of, Vp = 850, Vs = 550 and φ = −90
Project Portfolio Management: planning, selecting, and executing Development of a framework for prioritizing between innovation projects at a forest industry company
No full textFollowing a recent restructuring and new strategic directives, the Packaging Solutions
Business Expansion team (PSBE) at Stora Enso has begun to question how it works
with project portfolio management (PPM). This study explores the usefulness of a
formal PPM process for designing PSBE’s project portfolio and proposes a context specific framework for handling this. The research is qualitative in nature, based on
interviews with PSBE team members and representatives from external companies. The
internal interviews explored the current needs and challenges of PSBE, while the
external interviews provided insights into how other organizations work with PPM.
While the externally interviewed companies offer insight and best practices, differences
in context mean that their practices cannot be directly applied to PSBE. The findings
indicate that PSBE currently selects and prioritizes innovative project ideas in an
informal manner, and faces certain challenges related to it. A formal PPM framework
could help address these challenges. This research has led to a set of recommendations
for PSBE on how to work with PPM effectively. The proposed PPM framework
encompasses three phases: planning (setting strategic focus and deciding on evaluation
methods, including financial metrics, scoring models, and visualizations), selecting
(building the actual project portfolio through activities such as evaluating individual
projects and considering interdependencies and resource constraints), and executing
(realizing projects through continuous monitoring and incorporation of lessons
learned). Involvement of stakeholders throughout the process is crucial for success
Atostugan - South Sapmí Goathe
No full textOmkring 1920 byggde Tomas och Anna Klementsson en torv- kåta i närheten av Atoklimpen. Mitt i samebyns sommar- viste vid Risbäcken. Vid 1928 inrättades en nomadskola vid Atostugan, där samebarn fick undervisning under sommarveckorna. Skolan bestod av tre kåtor med varsin funktion. En kåta användes för undervisning, en annan kåta fungerade som matsal, där måltider tillagades och serverades och den tredje kåtan var sovsal, där barnen bodde under skolperioden. Undervisningen lades ned 1945, då den nya nomadskolan i Tärnaby kom till. En restaurerad kåta finns idag på platsen för att ge besökare en inblick i denna del av historien
Thermal simulations of a system-in-package for space applications
No full textFrontgrade Gaisler AB is investigating a System-in-Package (SIP) based on their
radiation hardened, fault-tolerant, octa-core, SPARC LEON and RISC-V microprocessor
(GR765) together with DDR4 memories. The SIP aims to provide reliable,
high performance processing in a small package form factor for space applications.
The packaging of processor and memories together increases the demands on the
package for proper thermal management. This task is further complicated by the
harsh space environment, which needs special considerations during the design process.
This work supports the developments of the GR765 SIP through thermal
simulations using computational fluid dynamics (CFD). Example models of the SIP
were built and simulated using ANSYS Icepak to determine where in the package
hot spots occurred, how heat transferred through different parts of the package, and
how different packaging methods and materials impacted the results.
The simulations of the thesis featured six different models. The first three models
centered around finding an appropriate level of detail, which should give accurate
results while not becoming too computationally intensive. These models also showed
the impact which simplifications like ideal contact resistances and homogeneous heat
generation had on temperature calculations. Model I, featuring both simplifications,
had a peak temperature of 43◦C lower than Model III which featured contact resistances
and uneven heat generation. The following two models focused on lowering
the package temperatures to fit a thermal target of 125◦C at an ambient temperature
of 55◦C. The results of these simulations showed that swapping a plastic overmold
for a metal lid could increase the peak temperatures of the package. With a dedicated
heat sink the peak temperatures were within the thermal target at 99◦C with
55◦C as the ambient temperature. The last model explored memory stacking using
film over wire (FOW). In these simulations, the stacked dies struggled with thermal
management resulting in a peak temperature of 151◦C in the memories at an ambient
temperature of only 20◦C. The combined results suggest that simplifications can
have a large impact on the results, a dedicated heat sink is needed for the design,
and additional thermal management methods are needed if die stacking is to be used
in this kind of SIP