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Coming dissertations at TekNat

  • Study of Student Electricity Use in Uppsala

    Author: Max Torbjörner Anthony Gundstedt Philip Shaposhnikov
    Publication date: 2020-07-02 08:51

    This report covers a project that set out to create our own and implement another existing measurement system that measures the power consumption in different student residences with higher resolution then what is currently offered by Vattenfall. This is important since there is a problem in Uppsala with a lack of power from the electrical grid which limits Uppsalas ability to grow as a city. Different dorm rooms in the housing area Gamla Studenstaden were then measured and data with the resolution of 1 minute was then analysed. This data was then used in order to answer which type of accommodation is most efficient with its power usage in relation to the amount of rooms. This report also wanted to answer how different types of accommodations cause spikes in their power usage which are only possible to spot with the higher resolution. The resulting data show that one-room apartments has relatively low power consumption over the day but contribute to so called power spikes which cause large load on the power grid. The dorm rooms did however seem to have a more distributed power consumption over the day.

  • Characterisation of natural dissolved organic matter with liquid chromatography and high resolution mass spectrometry

    Author: Claudia Patriarca
    Publication date: 2020-06-11 10:32

    Dissolved organic matter (DOM) is one of the most heterogeneous and complex mixture on Earth. DOM plays a crucial role in biogeochemical processes on the global scale and it is essential to sustain and regulate the biological processes in aquatic ecosystems. DOM originates from a multitude of biological, physical and chemical transformations, leading to its phenomenal chemical diversity. In order to understand and predict its effect on the global carbon cycle, an intimate characterization at molecular level is necessary. The investigation of the extraordinary complexity of the DOM mixture represents a compelling challenge for analytical chemistry. The focus of this thesis was the development of methods for the characterization of DOM in natural waters. High resolution mass spectrometry (HRMS), was combined with high pressure liquid chromatography (HPLC) and electrospray ionization (ESI), to investigate the chemical diversity of DOM. The first study demonstrated that cutting-edge techniques (such as the Fourier-transform ion cyclotron resonance mass spectrometer - FTICR-MS), are not indispensable to disclose essential information on the DOM molecular composition, in fact the...

  • Inertial motion capture for ambulatory analysis of human movement and balance

    Author: Fredrik Olsson
    Publication date: 2020-06-04 10:58

    Inertial sensors (accelerometers and gyroscopes) are ubiquitous in today’s society, where they can be found in many of our everyday mobile devices. These sensors are capable of recording the movement of the device, and by extension, the movement of humans carrying or interacting with the device. Human motion capture is frequently used for medical purposes to assess individual balance performance and movement disorders. Accurate and objective assessment is important in the design of individualized interventions and rehabilitation strategies.

    The increasing availability of inertial sensors, combined with their mobility and low cost, has made inertial motion capture highly relevant as a more accessible alternative to the laboratory based gold standard. However, mobile solutions need to be adopted for plug-and-play use with the end user in mind. Methods that automatically calibrate the sensors, and methods that detect and record relevant motions are required.

    This thesis contributes to the development of human inertial motion capture as a plug-and-play technology. A method for accelerometer calibration, which allows for compensation of systematic sensor errors, is...

  • Bacterial DNA repair and molecular search

    Author: Arvid H. Gynnå
    Publication date: 2020-06-04 08:45

    Surveillance and repair of DNA damage is necessary in all kinds of life. Different types of DNA damage require different repair mechanisms, but these mechanisms are often similar in all domains of life. The most serious type of damage, double stranded DNA breaks, are for example repaired in conceptually similar ways in both bacteria and eukaryotes. When this kind of breaks are repaired by homologous recombination, a homology to the site of the break must be found. Sometimes, this homology can be located far away from the break necessitating a search. Considering the large amount of heterologous DNA present, the complexity of this search is enormous. If and how this search can proceed has been unclear even in simple and well characterized organisms as E. coli.

    In this thesis, microscopy together with microfluidics are used to show that DNA repair by homologous recombination occurs even between homologies separated by several micrometers. We also see that it finishes well within the time of a cell generation, with the enigmatic search phase being as quick as eight or possibly even three minutes. Since this time is much faster than expected, we present a physical...

  • Cells and 2-representations of bimodules over Nakayama algebras

    Author: Helena Jonsson
    Publication date: 2020-05-28 15:50
  • Divergence, selection, demographic history and conservation genomics of sibling bird species in boreal forest in Northern Eurasia and the Qinghai-Tibetan Plateau

    Author: Kai Song
    Publication date: 2020-05-25 14:26

    I used two pairs of sibling boreal forest bird species to study divergence, selection, demographics, and conservation in northern Eurasia and the Qinghai-Tibetan Plateau at the microsatellite level (chapter 1) and whole genome level (chapters 2, 3, 4 and 5). In chapter 1, which is the first study to describe genetic diversity of the Sichuan Jay, I used microsatellite markers to estimate genetic differentiation in Sichuan Jay and Siberian Jay populations. The results showed similar levels of genetic variability, strong population structure, and high genetic differentiation between the two species and among different populations. In chapter 2, I used demographic analyses, and found that the Chinese Grouse has experienced substantial changes in population size from the beginning of the last interglacial, with a peak just before the last glacial maximum. The results inferred from the whole genome sequencing and species distribution models support a history of population size fluctuations. In chapter 3 to 5, I used population genomic methods to explore...

  • Beyond scattering – what more can be learned from pulsed keV ion beams?

    Author: Svenja Lohmann
    Publication date: 2020-05-20 13:36

    Interactions of energetic ions with matter govern processes as diverse as the influence of solar wind, hadron therapy for cancer treatment and plasma-wall interactions in fusion devices, and are used for controlled manipulation of materials properties as well as analytical methods. The scattering of ions from target nuclei and electrons does not only lead to energy deposition, but can induce the emission of different secondary particles including electrons, photons, sputtered target ions and neutrals as well as nuclear reaction products. In the medium-energy regime (ion energies between several ten to a few hundred keV), ions are expected to primarily interact with valence electrons. Dynamic electronic excitations are, however, not understood in full detail, and remain an active field of experimental and theoretical research. In addition, whereas scattered ions are employed for high-resolution depth profiling in medium energy ion scattering (MEIS), research on secondary particle emission in this regime is scarce.

    This thesis explores possibilities to experimentally study ion-solid interactions in the medium-energy regime beyond a backscattering approach. The capability...

  • Source analysis of multiplet earthquakes (two case studies in Iran)

    Author: Samar Amini
    Publication date: 2020-05-20 11:16

    Multiplet earthquakes are large earthquakes of similar magnitude which occur close in time in the same limited geographical area. They are not common but they considerably increase the potential hazard in the area in which they occur. This thesis studies source properties and triggering mechanisms of two sets of multiplet events in Iran, which both occurred in unexpected areas, but close to some major active fault systems. The first multiplet is an earthquake doublet (Mw 6.5 and Mw 6.4) which occurred in northwestern Iran and caused more than 300 fatalities and significant injuries. In paper I, a teleseismic body-waveform inversion was used to deduce the slip distribution pattern on the fault plane of the first mainshock. The estimated slip pattern was utilized to calculate the Coulomb stress changes on the second fault plane and on the following aftershocks. Based on this analysis, the ambiguity between the primary and auxiliary fault plane of the second mainshock could be resolved. The second set of events is a triplet (Mw 6.1 - 6.0) that occurred in eastern Iran, close to the Kerman province. In paper II, the rupture propagation patterns of the three mainshocks were analyzed...

  • Developmental exposure to mixtures of environmental pollutants : Studies on metabolism, developmental processes, and reproductive organs in zebrafish and chicken embryos

    Author: Anna Mentor
    Publication date: 2020-05-19 13:35

    Humans and wildlife are continuously exposed to mixtures of environmental pollutants. Mixture toxicity can be challenging to predict due to interactions between chemicals and thus whole-mixture approaches are crucial in toxicology. Developing organisms are generally more sensitive to chemical insult than adults and early exposure has been linked to metabolic and reproductive disorders later in life. It is thus imperative to clarify how mixtures of environmental pollutants affect early development.

    Within this thesis, consequences of early exposure to human-relevant chemical mixtures have been demonstrated using zebrafish and chicken embryos. The mixtures were designed previously based on negative associations with birth weight (mixture G) or anogenital distance (mixture S) in Swedish children. Mixture G consist of phthalate monoesters, perfluoroalkyl acids, and triclosan (TCS). It was assessed for effects on developmental processes (apoptosis and wnt/β-catenin signaling) and lipid metabolism in zebrafish. Two components of mixture G were assessed as single compounds: perfluorooctane sulfonate (PFOS) and TCS. Exposure to mixture G induced apoptosis, reduced wnt/β-catenin...

  • Atomistic Modelling of Low Dimensional Materials for Energy Harvesting and Gas Sensing Applications

    Author: S. Rabab Naqvi
    Publication date: 2020-05-19 11:29

    Energy crisis and pollution are the two biggest issues of the present times which are extremely important to address on priority. Scientists/Researchers are trying to explore and create alternate means of energy production which are sustainable and free from greenhouse emissions. Use of the hydrogen (H2) as an energy carrier can promise energy sustainability, economic viability, and environmental friendliness. H2 is abundant in nature and delivers the highest energy density compared to all types of fossil fuels. However, the gaseous nature of the H2 makes its storage difficult for practical applications. Previously employed H2 storage strategies (liquefaction and pressurized storage) suffer from economic and safety concerns. H2 storage in solid-state materials via non-dissociative adsorption is the most suitable technique. However, adsorption energies of the H2 with the storage medium are typically very weak therefore operations under ambient working conditions are not possible. We used density functional theory to design the H2 storage media, which are capable to adsorb H2 in a non-dissociative manner with high gravimetric capacity and adequate adsorption...

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