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I Sverige planeras det för höghastighetsjärnvägar, med högre hastigheter än vad som används idag, för att binda samman landets tre storstadsregioner. I samband med detta krävs ett utvecklingsarbete av olika järnvägstekniska lösningar där kontaktledning är ett av områdena som utvecklas för att möta högre hastighetskrav. Detta examensarbete syftar på att analysera och jämföra olika kontaktledningssySweden is planning for highspeed railway with higher speed than used today between the country's three large metropolitan regions: Stockholm, Gothenburg and Malmö. In connection with this, various technical solutions, where the overhead catenary system is one area, must be developed further to meet higher speed requirements. This thesis aims to analyse and compare different catenary systems ag

I många sammanhang är man intresserad av lösningar till ekvationer eller den geometriska strukturen av lösningarna till en mängd ekvationer, speciellt då det inte går att ange dem explicit. Även enkla exempel av detta finns: ekvationen $x^2+y^2=1$ definierar en cirkel, men det går inte att beskriva alla reella tal som löser den utan att man använder transcendentala funktioner. Algebraisk geometri We provide an introduction to scheme-theoretic algebraic geometry, which studies spaces that are in essence locally solutions to systems of polynomial equations, and prove the weak Mordell-Weil theorem. The weak Mordell-Weil theorem states that for an elliptic curve $E$ over a number field $K$, the quotient $E(K)/mE(K)$ is finite for all $m\geq 2$. The proof is adapted from a proof in the language

Klimatförändringar orsakade av människans aktivitet har de senaste åren varit i fokus runt om i hela världen. Bygg- och anläggningssektor som står för en femtedel av växthusgasutsläpp jobbar ständigt för att hitta hållbara och ekonomiskt lönsamma metoder för att uppnå uppsatta klimatmål. Inom asfaltsindustrin har biobaserade bindemedel den senaste tiden börjat testas för att undersöka potentialen Bio-based binders have recently been introduced to reduce the dependence on fossil raw materials, which bitumen is produced of. Measurements with dynamic shear rheometer (DSR) and rotational viscometer (RVB) were performed on mixtures with bitumen and two different types of bio-based binders, namely Lignin 1 and Lignin 2. Parameters like softness point, viscosity and parameters used to evaluate ru

Participation in corporate accelerator programmes is considered a powerful tool for early-stage start-ups for operational go-to-market and strategic business development acceleration. With the COVID-19 outbreak, all the activities related to the corporate accelerators were forced to move online. However, due to the novelty of the phenomenon, the influence of switching the modality of corporate acc

Capacity shortages in electricity grids can impose significant costs on society due to missed investments in industry. Due to limited profit opportunities and long lead times, grid reinforcements are not a viable solution to the problem, which must therefore be prevented through efficient use of existing grid resources. Local flexibility markets can financially compensate electricity users to shif

In this Bachelor's thesis, a solution to the Dirichlet problem using Brownian motion is given. Brownian motion is constructed using Kolmogorov's existence and continuity theorems. Blumenthal's zero-one law and the strong Markov property in various formulations are proven. Using these results, a solution to the Dirichlet problem is given using Brownian motion. The cone condition which g

This study analyzes the return to schooling in 22 countries. More specifically, the effect on earnings of receiving a bachelor’s and a master’s degree is estimated by applying a propensity score matching approach on microdata. Unlike many other techniques, propensity score matching addresses selection bias to a higher extent making the estimates of the treatment effect on the treated more reliable

PAPR Credentials is the name of a not yet published credential scheme that provides conditional privacy for its users. This means that an administrator can choose to revoke a user's anonymity. Doing so, however, the administrator must broadcast her intention, as the success of the privacy revocation depends on the help of other users, since the administrator does not have access to sufficient

Where do the children learn? A crucial part of our social construction, education and its space, has changed and is adapting to new knowledge and studies to improve the quality of the learning process. Space should represent the values and growth of society. The changing mindset does not mean that we deny or forget theories, strategies and resources that we have developed throughout history, but

This paper studies whether the level of IPO underpricing is enforced by increased firm complexity. Evidence from a sample of 215 Swedish IPOs between 2010–2020 suggests that investor’s ex-ante uncertainty increases as issuing firms become increasingly complex. As a consequence, firms exhibiting complexity generally experience higher degrees of IPO underpricing. Moreover, we find support for our cl

Den där blomman är min! Det är juni. Vart man än vänder blicken är det grönt och blommorna står som vackra färgklickar i allt det gröna. Fjärilar, bin och andra insekter surrar omkring bland blommorna i jakt på föda. Det myllrar av liv och olika arter. Men vart ifrån kommer egentligen all den mångfald av växter och insekter som vi ser? För att förstå biodiversiteten runtomkring oss och hur olikaA significant proportion of the diversity of species seen today are insects and their host plants, and the evolutionary mechanisms behind their radiation have long captured the interest of biologists. The peacock flies of the large genus Tephritis (Tephritidae) use different host plants in the family Asteraceae for their reproduction. There is variation both in use of host plant species and in the

How to study the infection of a parasite without using cats During the past 9 months, I have been studying a parasite, more specifically, how we can study the life of this parasite in the lab without using lab animals like mice or cats. I have tried and achieved to developed a way to do so, with mouse cells and a special fatty acid A parasite is a type of organism that depends on another living

Exploring the genetic basis of familial multiple myeloma Multiple myeloma (MM) is one of the most common forms of blood cancer. The disease is characterized by uncontrolled growth of plasma cells in the bone marrow, leading to bone marrow failure, kidney failure, bone lesions and death. Several studies have shown that some families are at an increased risk of developing MM, monoclonal gammopathy

Architecture is always intrinsically tied to place. Regardless of how architects choose to interact with and study it, the context our buildings are meant to inhabit is an important piece of the puzzle. As the world is getting more interconnected and geographical constraints are getting less important to the architectural profession, I am interested in how the creative process changes when assumpt