The purpose of the study is to determine how pre-school children between the ages of four and six perceive electricity. The study used observation as a method and a field study equipped with a video camera. A semi-structured interview was also conducted to capture the pre-school teacher’s experiences and perceptions of the study. The observation took place on three different occasions: a gathering, a lesson and a reading session. The material used was a fact-based children’s book with associated experimental material and tutorials. The result of the study showed that the children related their knowledge of what electricity is to their daily lives. They could distinguish whether things required electricity,and there was some knowledge that electricity has a source and of electricity's dangers. During the study, pre-school teachers raised both opportunities and challenges to design activities with electricity. The children showed great dedication and general knowledge of electricity and thought that the subject was interesting. There is a need for further education within physics and natural sciences for pre-school teachers. The goal for the pre-school teachers is to create a balance so that each and every child is offered meaningful education. / Syftet med studien är att ta reda på vilka uppfattningar förskolebarn i åldern 4-6 år har om elektricitet. Studien använde observation som metod, en fältstudie med videokamera som redskap. En semistrukturerad intervju utfördes också för att kunna fånga upp förskollärarnas erfarenheter och uppfattningar om studien. Observationen gjordes under tre olika tillfällen: en samling, en undervisning och en lässtund. Materialet som användes var en faktasaga med tillhörande experimentsats och handledning. Resultatet i studien visar att barnen relaterar sina kunskaper om vad elektricitet är genom att förhålla sina svar till deras vardag. De kan skilja på saker som kräver elektricitet eller inte, det finns viss kunskap i att elektricitet har ett ursprung och om elektricitetens fara. Under studien lyfter förskollärarna både möjligheter och utmaningar i att genomföra en aktivitet om elektricitet. Barnen visar ett stort engagemang och breda förkunskaper om elektricitet och tycker att ämnet är intressant. Det finns ett behov av ytterligare utbildning inom fysik och naturvetenskap för förskollärare. Att skapa balansen så att förskollärare kan ge alla barn och erbjuda varje barn en meningsfull undervisning för dem blir målet.

Fysiklärare möter ofta den svåra uppgiften att representera abstrakta, väldefinierade egenskaper hos den fysiska världen (så som krafter eller energier) för studenter som går bortom ekvationer, grafer eller diagram. I denna studie tittar jag två fall av universitetsstudenter som löser en fysikalisk uppgift, användandes det digitala programmet Algodoo på en stor pekskärm för att undersöka hur studenter naturligt använder sig av sådan teknologi för att återskapa dessa representationer själva. Jag finner att när studenter skapar scener i Algodoo prioriterar de att behålla en viss mått av likhet från den fysiska världen, vilket går bortom den formella behandlingen av uppgifter som studenter kan ha fått lära sig i fysikundervisningen. Vidare, när studenterna använder sig av fysikaliska ekvationer vid lösandet av problemet, verkar de använda Algodoo som ett facit för att se huruvida deras numeriska lösning, uträknad på en klassisk whiteboard, stämmer. På detta sätt - vilket har föreslagits i tidigare forskning - ser jag hur Algodoo, och liknande digitala lärmiljöer, fungerar som en bro mellan studenternas konceptuella förståelse av den fysiska världen, och den mer formella, matematikbaserade beskrivningen vilket används inomfysiken. / Physics teachers are often faced with the difficult task of representing abstract, formally-defined properties of the physical world (such as forces or energy) for students in a way which goes beyond equations, graphs, and diagrams. In this study, I investigate two cases of university students solving a physics problem while using the digital software, Algodoo, on a large touch screen to examine how students might naturally leverage such technology to create such representations of their own. I find that as student draw scenes in Algodoo, they tend to prioritze a degree of resemblance to the physical world which goes beyond the formal treatment of problems they might have been taught in physics classes. Additionally, as the students recruit physics equation into their solution of the problem, they appear to use Algodoo as a conceptual check for the numerical answer they calculate on the normal whiteboard. In this way - and as has been hypothesized in previous research - I see the potential for Algodoo and similar digital learning environments to act as a bridge between students’ conceptual intuitions of the physical world and the more formal, mathematically-based descriptions used in physics.

We introduce the historical context and motivation for the search for magnetic monopoles or monopole-like objects. Beginning the theoretical part we investigate the properties of groups as they relate to symmetries in physical theories. Using this as a basis we investigate the requirements for global and local gauge invariance for a scalar field, the latter giving the non-trivial connection to a gauge field. From this we present the Georgi-Glashow model and develop its particle spectrum using the connected Higgs field and its associated Higgs mechanism. We then present the electromagnetic duality by extending the Maxwell's equations toinclude magnetic sources. Using the assumption of magnetic sources we present the Dirac quantization condition, motivating the quantization of electric charge. Returning to our model we present the 't Hooft-Polyakov ansatz and investigate its defining properties as a finite energy soliton in our Higgs field. We show the magnetic properties and motivate its validity as a monopole like object. Continuing we define BPS-states on the lower bound for the mass of a monopole like object with magnetic and electric charge. Giving a BPS monopole as a solution in the vein of 't Hooft and Polyakov. Returning to the electromagnetic duality we propose the Montonen-Olive conjecture by exchanging massive vector bosons in our model with the BPS monopoles we developed. We shortly comment on evident problems and present supersymmetry as a possible solution. Finally we present the Witten Effect by allowing a CP violating term in our Lagrangian. From this we extend the Montonen-Olive conjecture to include invariance under the SL(2,Z) group.

In this project a recent model of inflation in which the Standard Model Higgs field with a nonminimal coupling to gravity takes on the role of the inflaton field is investigated. The tensor to scalar ratio, spectral index and the running of the spectral index  is calculated for a tree level analysis and compared with the Planck experiment. The value of the nonminimal coupling constant $\xi$ is estimated by obtaining a relation between the amplitude of scalar perturbations and the Higgs mass, it is found that $\xi \sim 10^4$. The basic aspects of how the results are modified through quantum corrections and what the consequences of the nonminimal coupling are for the effective field theory description is discussed. It is found that a tree level analysis yields predictions which are inside the allowed regions of the cosmological parameters given by the Planck experiment. The large value of the nonminimal coupling leads to unitarity problems for this model of inflation.  However quantum effects will have a significant effect and how they modify the results of the tree level analysis is what decides if Higgs inflation is a viable theory. / I detta projekt undersöker vi en modell av kosmisk inflation där Higgsfältet med en ickeminimal koppling till tyngdkraften är mekanismen bakom inflation. Vi utför en klassisk analys och beräknar modellens föresägelser för ett antal kosmologiska parametrar som jämförs med Planck experimentet. Vi uppskattar värdet på den ickeminimala kopplingen $\xi$ och finner att $\xi \sim 10^4$. De grundläggande aspekterna bakom kvantanalysen samt vad effekten av den ickeminimala kopplingen har på beskrivningen i termer av en effektiv fältteori diskuteras. Vi finner att en klassisk analys ger förutsägelser som passar väl med Planckexperimentet men att den ickeminimala kopplingen leder till unitaritetsproblem för denna modell av inflation. Kvanteffekter kan dock ha en avsevärd effekt på resultat och en utförlig analys som tar dem till hänsyn krävs för att avgöra om Higgsinflation är en möjlig modell för inflation.

Today there exist few non-smooth multi-domain simulation tools using time-discretized Lagrangian mechanics for circuits.The main goal is to show that itis possible to use a semi-implicit, parameter free non-smooth variational timestepper to simulate the circuits with time-steps proportional to the system timescales.This is demonstrated by implementing and performing extensive numericaltests for various types of electrical, mechanical and hydraulic components anddemonstrate that the components are stable, with the correct behavior whenthe system is solved using a modified block pivot solver.Simulation results shows that piecewise linear models are enough for thesimple switching circuits in this thesis. / Idag finns det få simulatorer för icke-släta multidomän kretsar som bygger på tidsdiskretisering av Lagranges ekvationer. Huvudmålet är att visa att det är möjligt att använda en semi-implicit, parameter fri icke-slät diskret lösare för att simulera kretsar med tidssteg proportionella mot systemens tidsskalor. Detta visas genom att implementera olika typer av elektriska, mekaniska och hydrauliska komponenter samt att visa att komponenterna är stabila och har rätt beteende när systemet simuleras av en modifierad block pivot lösare. Simulerings resultaten visar att icke-släta Newton metoder med styckvis-linjära komponenter och komplementära villkor är tillräkligt för att simulera brytande komponponenter i de simulerande kretsarna.

Structured products are complex non-linear financial instruments that make it difficult to calculate their future risk and return. Two categories of structured products are Capital Protected and Participation notes, which are built by bonds and options. Since the structured products are non-linear, it is difficult to asses their long-term risk today. This study, conducted at Nordea Markets, focuses on the risk of structured products and how the risk and return in a portfolio changes when we include structured products into it. Nordea can only calculate the one-year risk with their current risk advisory tool, which makes long time predictions difficult. To solve this problem, we have simulated portfolios and structured products over a five-year time horizon with the Monte Carlo method. To investigate how the structured product allocations behave in different conditions, we have developed three test methods and a ranking program. The first test method measures how different underlying assets changes the risk and return in the portfolio allocations. The second test method varies the drift, volatility, and correlation for both the underlying asset and the portfolio to see how these parameters changes the risk and return. The third test method simulates a crisis market with high correlations and low drift. All these tests go through the ranking program, the most important part, where the different allocations are compared against the original portfolio to decide when the allocations perform better. The ranking is based on multiple risk measures, but the focus in this study is at using Expected Shortfall for risk while the expected return is used for ranking the return. We used five different reference portfolios and six different structured products with specific parameters in an example run where the ranking program and all three test methods are used. We found that the properties of the reference portfolio and the structured product’s underlying are significant and affect the performance the most. In the example run it was possible to find preferable cases for all structured products but some performed better than others. The test methods revealed many aspects of portfolio allocation with structured products, such as the decrease in portfolio risk for Capital Protected notes and increase in portfolio return for Participation notes. Our ranking program proved to be useful in the sense that it simplifies the result interpretations.

One of the traditional approaches to reduce costs of solar energy is to use inexpensive reflectors to focus the light onto highly efficient solar cells. Several research projects have resulted in designs, where the excess heat is used as solar thermal energy. Unlike a solar thermal system, which has a selective surface to reduce the radiant heat loss, a CPV/T (Concentrating PhotoVoltaic/Thermal) system uses a receiver covered with solar cells with high thermal emittance. This project analyzes whether the heat loss from the receiver can be reduced by covering parts of the receiver surface, not already covered with solar cells, with an optically selective coating. Comparing different methods of applying such a coating and the long-term stability of low cost alternatives are also part of the objectives of this project. To calculate the heat loss reductions of the optically selective surface coating a mathematical model was developed, which takes the thermal emittances and the solar absorptances of the different surfaces into account. Furthermore, a full-size experiment was constructed to verify the theoretical predictions. The coating results in a heat loss reduction of approximately 20 % in such a CPV/T system and one of the companies involved in the study is already changing their design to make use of the results.

In this thesis, two MFC based films Carboxymethylated-Microfibrillated Cellulose (MFC) and Enzymatic-MFC were characterized and metalized in order to improve the barrier properties at high relative humidity. Several methods were used for the characterization process, which were Atomic Force Microscopy (AFM), Contact Angle (CA), Energy Dispersive Spectra (EDS), Light Microscopy (LM), Scanning Electron Microscopy (SEM), and Oxygen Transmission Rate (OTR). Physical Vapor Deposition (PVD) system was used for the metalization of film, a thin layer of aluminium with a thickness of 200 nm was deposited on the films. The results revealed that ENZ-MFC exhibit a higher roughness and lower OTR values, compared to CM-MFC. The contact angle values proved that both non-metalized MFC films exhibited a hydrophilic surface with values around 50 degrees. SEM and EDS images showed that both films exhibited surface defects with dimensions in the order of a micrometer. The best barrier improvement by metalization was achieved for the metalized CM-MFC, where the OTR values were decreased by one order of magnitude after metalization. However, for ENZ-MFC metalization did not improve OTR at high RH. The protective layer was successfully protecting the MFC film as long as the surface roughness of the film was not too high. The limit is between 40 and 140nm (in root mean square roughness values). / I denna avhandling karakteriserades två MFC-baserade filmer Carboxymethylated-MFC och   Enzymatic-MFC som metalliserades för att förbättra barriäregenskaperna vid hög relativ fuktighet. Flera metoder har används för karaktäriseringsprocessen, vilka var Atomic Force Microscopy (AFM), Contact Angle (CA), Energy Dispersive Spectra (EDS), Light Microscopy (LM), Scanning Electron Microscopy (SEM), och Oxygen Transmission Rate (OTR). Physical Vapor Deposition (PVD) systemet användes för metalliseringen av filmerna, där ett tunt skikt aluminium med en tjocklek av 200 nm deponerades. Resultaten visade att ENZ-MFC har högreråhet och lägre OTR-värden jämfört med CM-MFC. Kontaktvinkelvärdena påvisade att bådaicke-metalliserade MFC-filmer har en hydrofil yta med värden omkring 50 grader. SEM- och EDS-bilder visade att båda filmerna har ytdefekter i storleksordningen en mikrometer. Den bästa barriärförbättringen genom metallisering uppnåddes för den metalliserade CM-MFC, där OTR-värdena minskade med en storleksordning efter metallisering. För ENZ-MFCförbättrade dock metallisering inte OTR vid hög RH. Det skyddande skiktet skyddar effektivt MFC-filmen så länge som filmens ytråhet inte var för hög. Gränsen är intervallet mellan 40 och140 nm (Kvadratiskt medelvärde för ytråhet).

In 1972 Fujishima and Honda conceptualised a photoelectrochemical cell for hydrogen generation via PEC water splitting. Hydrogen as a clean energy carrier provides environmentally friendly energy storage solutions or can fuel certain applications. This idea has since then been further built upon with new materials and combinations with the aim of improving efficiency. In this project n-type cubic silicon carbide thick layers were grown by a sublimation method and characterised for water splitting performance. A generated photo-current density of 0.45 mA/cm2 was measured with no bias between the working and counter electrodes.

Students’ interactions can be an influential component of students’ success in an interactive learning environment. From a participation perspective, learning is viewed in terms of how students transform their participation. However, many of the seminal papers discussing the participationist framework are vague on specific details about what student participation really looks like on a fine-grained scale. As part of a large project to understand the role of student participation in learning, this study gathered data that quantified students’ participation in three broad areas of two student-centered introductory calculus-based physics classes structured around the Investigative Science Learning Environment (ISLE) philosophy. These three broad areas of classes were in-class learning activities, class review sessions that happened at the beginning of every class, and the informal learning community that formed outside of class time. Using video data, classroom observations, and students’ self-reported social network data, this study quantified students’ participation in these three aspects of the class throughout two semesters. The relationship between behaviors of students’ engagement in various settings of an active learning environment and (a) their conceptual understanding (measured by FCI gain) and (b) academic success in the courses as measured by exam scores and scores on out-of-class assignments were investigated. The results from the analysis of the student interaction in the learning process show that three class components, viz. the Review Session, Learning Activities, and Informal Learning Community, play distinct roles in learning. Students who come in the class with better content knowledge do not necessarily participate more in the learning activities of active learning classrooms. Learning Communities serve as a “support network” for students to finish assignments and help students to pass the course. Group discussions, which are facilitated by students themselves, better help students in gaining conceptual understanding. Since patterns of students’ participation do not change significantly over time, instructors should try to ensure greater participation by incorporating different learning activities in the active learning classroom.