The main topic of this thesis is experimental analysis of material surfaces using scanning probe microscopies. These microscopes are used for characterization through high-resolution topographical imaging, but also for controlled modification of surfaces and molecules. The surface characterization includes evaluation and development of fractal methods for surface roughness determination. The term modification is used for manipulating the structures on a microscale by scraping them with a tiny tip. The major application of this technique in the present work is the analysis of effects induced by plasma-surface interactions. Such studies are fundamental in the understanding of erosion and deposition processes on the first wall in controlled fusion devices. In this work, scanning probe microscopes were for the first time used for studying such plasma-facing materials. Both the surface structure and composition have to be known in order to evaluate new wall-materials for fusion reactors. The materials studied here are graphites, SiC/Al coatings, graphite-silicon mixtures and various silicon carbide based composites. They were all exposed to plasmas, either to lowenergy deuterium plasmas and ions in laboratory experiments, or to the plasma in a socalled tokamak. The results show the usefulness of these high-resolution microscopes in the study of plasma-surface interaction. Several other surface sensitive techniques were also applied, at the home laboratories of our collaborators, the most important ones being Rutherford backscattering spectroscopy and nuclear reaction analysis. The scanning probe microscopy in combination with the ion-beam analysis made it possible to trace fine structural features on the surfaces and to measure the surface roughness. The main results are: (i) the detection of the initial stages of bubble/blister formation on CSi mixtures, SiC/AI coatings and graphites; (ii) the morphological changes and the physical properties of the silicon carbide composites; (iii) the distinction of radiation damages on different phases of multicomponent composites; (iv) the estimation of layer thickness with scanning probe microscopy; (v) the determination of the structure of codeposited layers formed during exposure in a tokamak; (vi) the uptake of deuterium by the materials. The atomic force microscope has also been used to study the human protein spectrin, and we managed to image free spectrins with molecular resolution in an almost natural environment. The elongated spectrin macromolecule was found to be 100 rim long and 5 nm broad. Indications of a substructure were observed. The force between the sensor tip and the molecules was crucial, both for sample movement, manipulation and image resolution. Therefore, the instrument was rebuilt to operate with so called tapping-mode in liquid. Preliminary results with this method on spectrin are presented. / Godkänd; 1995; 20070410 (ysko)

The subject of this thesis is "the fundamental structure of matter, that is, the quest of understanding the deepest level of the physical world, and the interactions relevant at that level. The hope is that, as one goes deeper, the laws are going to be simpler, not necessarily in mathematical terms, but in conceptual terms. The goal is fewer and fewer ad hoc assumptions, inspiring and driving the pursuit for the fundamental structure of matter. The thesis consists of an introductory part, giving a broad overview of where the subject stands today, and of a more detailed part, containing our own contributions to the advances of this knowledge. Six reproduced papers are appended at the end. There we treat the fundamental structure of matter on three different levels. The first three papers are concerned with the inner structure of particles (hadrons) that interact via the strong nuclear force. Here we have investigated the interactions of the so-called quarks inside hadrons, taking into account also their spin structure. Besides protons and neutrons, we have also studied more exotic particles containing quarks, so-called mesons, that are only produced in high-energy collision processes. Om a more fundamental, but speculative, level we have constructed a new model for an underlying substructure common to both quarks and leptons (particles unaffected by the strong interaction), i.e., all particles that build up matter. We also investigate some of the physical consequences of this model, particularly the possibility of radiative neutrino decay. On the large scale, we analyse the origin of the so-called dark matter in the Universe, which we propose is composed out of enormous lumps exclusively made of quarks, without any "normal" hadrons. We also explore the connection of this phenomenon to the mysterious bursts of gammarays seen in astrophysics. / Godkänd; 1998; 20061123 (haneit)

We set out on the ambitious journey to fuse inflation and string theory. We first give a somewhat extensive, yet free from the most complicated details, review of string inflation, discussing concepts as flux compactifications, moduli stabilization, the η-problem and reheating. Then, we consider two specific configurations of type II supergravity; type IIB on T6 with D3-branes and O3-planes, and type IIA on a twisted torus with D6-branes and O6-planes. In both cases, we calculate the scalar potential from the metric ansatzes, and try to uplift it to one of de-Sitter (dS) type. In the IIA-case, we also derive the scalar potential from a super- and Kähler potential, before we search for stable dS-solutions.

The Light Wave Synthesizer 20 (LWS20) is an Optical Parametric Synthesizer (OPS) system used for relativistic attosecond physics research. The LWS20 performs OPS through the means of multiple two-color pumped Noncollinear Optical Parametric Chirped Pulse Amplification (NOPCPA) stages. NOPCPA is basedon the nonlinear optical effect Optical Parametric Amplification (OPA) which is only described analytically through simplified expressions. A natural route around this difficulty is through the means of numerical models. In this thesis a (2+1) dimensional simulation software [1], [2] is used to simulate the four currently present NOPCPA stages of the LWS20, operated under two different options. The simulationwill be key to the planned upgrade of the LWS20, propelling the system fromthe current 16 TW power [3] to the wanted 100 TW power domain. It is shown that the used software is able to, with some caveats, emulate the results achieved in a laboratory environment and that the two operational options are optimized under slightly different settings. Furthermore, some barely documented, albeit crucial, features of the simulation software have been exposed, indicating that it is not very well optimized for simulating the OPA processes of the LWS20. By increasing the pump energy of the simulation beyond the realisticlevel it is still possible to attain relatively realistic amplification and thus the software ought to prove a valuable tool for the planned system upgrade. Some alternative approaches to the continuation of the simulations are presented which would further increase the software’s usefulness in the process of expanding theLWS20. Historically, the LWS20 has been operated successfully under the sameconditions under the two possible operational options, but the simulations clearly show that an optimized set-up for one option is far from optimal for the other option. Therefore, there is a possibility to further optimize the LWS20, an idea worth pursuing in future experiments.

Carbon nanotubes (CNTs) have attracted an immense attention of the research community since reporting on this system by S. Ijima in 1991. A "single-walled" CNT (SWCNT) can be considered as a rolled-up single-layer graphene - a one atom-thick layer of carbon atoms arranged in a hexagonal lattice. This cylindrical object being just about 1 nm in diameter and up to a few centimeters long can be considered as a quasi-one-dimensional system. Several nanotubes "inserted" one into another build a so-called multi-walled CNT. CNTs exhibit outstanding mechanical, thermal and electronic properties which make this material a promising candidate for numerous applications - reinforced composite materials, nano-electronics, molecular sensors and drug delivery systems to name just a few. CNTs possess tensile strength 10 and 5 times higher than that of steel and Kevlar, respectively, that creates a great prospective for their use as reinforcing units in materials subjected to high-impact dynamic loads/stress (bullet-proof jackets, for example). Nonetheless, to date there are no reports on experimental study of CNTs behavior at extreme dynamic loads which may substantiate such prospective. In addition, several theoretical predictions indicate a possibility of CNTs transformation into new structural forms at extreme pressures. The goal of this work is a systematic study of structural properties and exploration possibility of synthesis of new materials from CNTs under extreme pressures/stress.In a set of experiments purified SWCNTs were subjected to high dynamic (shock) pressures up to 52 GPa. Recovered from each pressure step sample was characterized by High Resolution Transmission Electron Microscopy (HRTEM) and Raman spectroscopy. We observed a gradual increase of defects concentration on the CNT surface with pressure along with shortening and "un-zipping" of the tubes and an onset of the complete CNT destruction at 26 GPa shock which sets-up a limit for certain practical applications of this kind of material. Further increase of the dynamic load to 35 and 52 GPa led to CNT transformation into a mixture of disordered sp²/sp³- bonded carbon atoms with nano-sized graphene clusters. No CNT polymerization or coalescence was observed contrary to some theoretical predictions. For comparison, we conducted a separate experiment on the same CNT material under static compression up to 36 GPa in a diamond anvil cell (DAC). The system evolution was monitored in-situ during the high-pressure run using Raman spectroscopy. Examination of the material recovered from high pressure revealed that certain fraction of the CNTs survived exposure to 36 GPa though similar damages were introduced to the nanotubes as in the shock experiments evidenced by the Raman spectra. This result testifies a substantial difference in the processes of CNT destruction by dynamic vs static compression.A separate set of experiments in DACs was aimed at in-situ monitoring of the Raman spectra (in particular G-band) during pressure evolution and establishing the level of static pressure which causes a complete destruction of SWCNTs from the same batch as used in similar experiments at the dynamic compression. Pressure dependence of G-band, G(p), exhibited several peculiarities at approximately 15, 45 and 60 GPa which we associate with collapse of large (1.2 nm) and small (∼1 nm) diameter CNTs, and an onset of nanotubes transformation to a new phase respectively. Raman spectra of the sample recovered after 58 GPa static compression exhibit no RBM signal, large G-band broadening and high D/G peak intensity ratio that testifies for CNT destruction. Pressure increase to 100 GPa resulted in a substantial altering of Raman spectrum of the recovered sample - appearance of characteristic features of highly disordered sp²-and sp³-bonded carbons which may stem from interlinked nano-sized graphene clusters.Change of CNTs structure results in the altering of their electronic properties thus structure evolution of the CNTs with pressure may be followed by monitoring electrical resistance change with pressure. In a series of experiments we conducted in-situ electrical resistance (R) measurements of the SWCNTs under static pressures up to 45 GPa (temperature range 293 - 395 K) in a conductive DAC. Isobaric temperature dependence of the resistance indicated that the nanotube sample is comprised predominantly of semiconducting CNTs. A set of anomalies observed in R(p) at room temperature we interpret as a sequential, diameter-dependent collapse of the CNTs. Raman characterization of the samples after the pressure cycling confirmed reversibility of these structural transitions for at least certain CNT species accompanied by a substantial increase of CNT defects density. No indication of nanotubes polymerization was observed.Although thermal conductivity of individual CNTs is excellent (5 times better than that of copper) heat conduction becomes far less efficient in "conventional" system, i.e. when the tubes form bundles/ropes which may lead to a risk of CNT destruction by overheating. Therefore probing CNTs response to extreme heat (temperature) is important both for testing capabilities of the nanotube material and developing methods of its proper characterization. We followed temporal evolution of the Raman spectra of bundled SWCNTs exposed to high laser irradiance in both air and argon atmosphere. Temperature threshold for CNT destruction in air appeared to be lower than that in Ar, the fact indicating importance of the CNTs oxidation for their structural integrity. We show that primary damage occurs in resonant with excitation laser CNTs which act as photon energy absorbers. We show that smaller diameter and metallic nanotubes are less stable to high irradiance/heat flux than their large diameter/semiconducting counterparts. Remarkably, some small diameter, non-resonant CNTs were destroyed indirectly, i.e. via overheating induced by neighbor CNTs in resonance (photon absorbers). We demonstrate the importance of laser heating effects on Raman characterization of nanotubes.Even though carbon nanotubes exhibit susceptibility to extreme pressure/stress and high laser irradiance/overheating their potential for use in very demanding applications is not yet challenged: for example SWCNT destruction under dynamic compression occurs at pressure exceeding 20 times the typical threshold levels in ballistic impact. Cold compression of nanotubes also opens up perspectives of synthesis of new carbon phases with superior mechanical properties. / Godkänd; 2014; 20141216 (maxnoe); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Maxime Noël Ämne: Fysik/Physics Avhandling: Physical Properties and Structural Stability of Carbon Nanotubes Under Extreme Conditions Opponent: Professor David Dunstan, School of Physics and Astronomy, Queen Mary, University of London, London, Ordförande: Professor Alexander Soldatov, Avd för materialvetenskap, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet Tid: Fredag den 30 januari, kl 10.00 Plats: E231, Luleå tekniska universitet

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Detta avslutande självständiga arbete handlar om visualiseringar i undervisningen inom naturvetarprogrammet och då främst inom ämnet biologi på gymnasiet och då främst avseende hur eleverna upplever användningen av visualiseringar i undervisningen. Bakgrunden till detta arbete är att i undervisningen inom biologi ska eleverna enligt Skolverkets läroplan Lgr 11 få möjligheten att utveckla förmågan att ”… använda kunskaper i biologi för att kommunicera samt för att granska och använda information.” Modeller och begrepp som är centrala i undervisningen anges i centrala innehållet inom respektive kurs i biologi och bl.a. cellen och cellers egenskaper, funktioner och kommunikation, cellmetabolism, ekosystem, evolutionen, fotosyntesen, livscykler, människan och andra organismers fysiologi ska ingå (Skolverket, 2011a). I Sverige har vi ett flertal forskare som forskar kring visualiseringar i undervisningen med olika inriktningar och jag har försökt att belysa delar av deras forskning i min bakgrund till uppsatsen för att försöka sätta in läsaren i forskningen kring olika former av visualiseringar. Flera av dessa forskare inriktar sin forskning till områden som berör ämnet biologi i stort. Syftet med arbetet var att försöka ta reda på elevers erfarenheter av användningen av visualiseringar genom två enkätundersökningar. Enkätundersökningen har, främst, fokuserat på hur visualiseringar används inom ramen för biologiundervisningen på naturvetarprogrammet på gymnasiet och hur eleverna upplever detta. Frågeställningarna i enkätundersökningen var: Hur uppfattar eleverna användningen av visualiseringar i undervisningen, med tyngdpunkt på ämnet biologi, på naturvetarprogrammet? Hjälper visualiseringar i undervisningen på naturvetarprogrammet eleverna i deras lärande, enligt eleverna själva? En tredje fråga som fick sitt svar under processens gång utan att ha varit en fråga som arbetet tog sin utgångspunkt i, utan var en fråga i enkäten var: Hur anser eleverna att man bör följa upp visualiseringar i undervisningen? Jag fann att eleverna till stora delar upplever att de är hjälpta av visualiseringar i undervisningen.

Anthropogenic emissions of greenhouse gases are widely known to have damaging effects on the world’s environment. In the search for green energy, recent studies propose that hydropower, which is considered a renewable source of energy, contribute significantly to the emissions of carbon dioxide and in particular methane gas to the atmosphere. Hydropower dams can globally act as an important carbon source, however they can bury substantial amounts of carbon and simultaneously act as net carbon sinks. The main objective of this study is to determine, with high spatial resolution, OC burial in a tropical reservoir, Camargos, Brazil, and compare data with two reservoirs downstream to see if there is any effect of multiple damming. This master’s thesis included field studies in terms of sub-bottom profiling and sediment coring. This was followed by data analysis and mapping of seismic survey data as well as lab work including organic carbon content analysis, C:N ratio and particle size calculations in order to estimate sediment characteristics. The results propose that there is significant burial of organic carbon in Camargos reservoir, of 57.7 g C m-2 yr-1 and 121.3 g C m-2 yr-1 by sub-bottom data and individual coring respectively and evidently, reservoirs further upstream tend to accumulate more sediment and have a higher rate of OC burial. More precisely, the sub-bottom data indicate a steady decrease in OC burial rates of approximately 20%, per dam following the cascade of reservoirs downstream. However, in order to rely on hydropower as a sustainable renewable source of energy to meet the demands of a world wide growing population and economy it is essential to continue studying this topic to fully understand all aspects of the carbon processes within these systems and whether they function as substantial net sinks or sources. / Minor field studies / HYDROCARB- European Research Council

Background: Fluoroscopy is a common imaging technique which uses X-ray to derive a real time imaging of patient anatomy to determine diagnosis and positioning of patients for interventional procedures. It is therefore important that the fluoroscopy systems maintain their performance. Assessment of image quality parameters (such as: low contrast resolution, uniformity, homogeneity and detection of defective pixels and artifacts) is one way to assess if they maintain their performance. This study aims to develop and implement a Matlab script to do a remote Quality Control (QC) and set up tolerance levels on different types of fluoroscopy systems.                                        Method: Three fluoroscopy systems were used in this project, Siemens Axiom Artis Zee MP, Siemens Cios Alpha and Ziehm Vision RFD. There were two setups used in the study for image acquisition by adding a 2 mm Cu filter as the attenuating material placed directly on the X-ray tube. A Cylindrical aluminum contrast detail of dimension 4 mm thick and 6 mm diameter was placed in the middle of X-ray field (Setup 1 on patient couch and setup 2 directly on the flat panel detector). The fluoroscopic images were acquired with and without contrast detail over a period of six month. The image quality parameter SNR2rate was determined from signal and background images while other quality parameters such as kerma-area product rate PKA, rate, uniformity, homogeneity, low contrast resolution, SNR, defective pixels and artefact detection were examined and determined from the background images. Two additional supporting experiments were performed, one with a chest phantom and 13 cm PMMA and the other one a human visual detection 4-AFC experiment.                 Result: The image quality index SNR2rate and the dose rate index PKA, rate, the low contrast resolution parameter (LCRP), uniformity, homogeneity and SNR values were within ±2 standard deviation for repeated measurements in each system. Nevertheless, the result indicates that Siemens Axiom Artis Zee MP has the best performance while Ziehm Vision RFD has the worst performance between these three systems. The result from the defective pixel method indicate that for 20 % tolerance there were no defective pixels for Siemens Axiom and Cios Alpha. Ziehm Vision had also no defective pixels for 30 % tolerance. The artefact detection shows that artefact level is high for fluoroscopy systems and Ziehm Vision RFD has artefact level more than 50 % tolerance.  The chest phantom experiment indicate that SNR2rate varies considerably over the lung anatomy as expected.           The 4-AFC experiment indicates that the effective time was 0.14 s for human observers to integrate the information in the live image.           Conclusion: The methods developed and implemented in this project were successfully able to determine and assess the image quality parameters such as SNR2rate,PKA, rate, low contrast resolution, uniformity, homogeneity, SNR and detection of defective pixels. Further effort is needed for installation of Matlab script on our local server, connection with Excel program and internal website (SharePoint) and adding more clinical fluoroscopy systems to do remote QC in Region Östergötland.

Biologisk mångfald är en förutsättning för leverans av ekosystemtjänster vilka utgör en viktig resurs för människan. Idag förekommer ett antal hot mot den biologiska mångfalden varav förlust och fragmentering av habitat räknas till de största. Modeller för att uppskatta biologisk mångfald på landskapsnivå är således viktiga verktyg i bevarandebiologi och vid planering av grön infrastruktur. Detta examensarbete är en studie kopplat till ett pågående forskningsprojekt vid högskolan i Skövde som finansieras av Naturvårdsverket där syftet är att ta fram en ny biodiversitetsindikator på landskapsnivå; Landscape Biodiversity Capacity Index (LBCI). I detta examensarbete prövades en av LBCI:s teoretiska variabler med korrelationsanalyser mot empiriska data från landmiljön betesmark i Sverige för att utvärdera dess förmåga att göra teoretiska uppskattningar mot empirin. Variabeln som testades var Biotope Functional Capacity (BFC). Testerna utfördes genom att i södra och mellersta Sverige slumpa 20 replikat ifrån vilka empiriska data erhölls från betesmarker genom Nationell Inventering av Landskapet i Sverige (NILS). Den empiriska datan sammanställdes i fyra olika diversitetsindex; artantal, Shannons index, Simpsons index of diversity och Simpsons reciprocal index. Avslutningsvis utfördes statistiska korrelationsanalyser vilka inte påvisade någon korrelation mellan BFC och diversitetsindexen. Orsaker till detta kan bland annat bero på hur den empiriska datan har analyserats och sammanställts eller brister i variabeln BFC. Denna studie har trots det bidragit till viktiga synpunkter vid den fortsatta utvecklingen av den nya biodiversitetsindikatorn LBCI och metodutveckling för att i fortsättningen undersöka samband mellan variabeln BFC och empiriska värden. / Biodiversity is a prerequisite for the delivery of ecosystem services, which constitute an important resource for man. Today, there are several threats to biodiversity, of which loss and fragmentation of habitats are among the largest. Models for estimating biodiversity at the landscape level are thus important tools in conservation biology and in green infrastructure planning. This thesis is a study linked to an ongoing research project at the University of Skövde, which is financed by the Swedish Environmental Protection Agency. The aim is to develop a new biodiversity indicator at the landscape level; Landscape Biodiversity Capacity Index (LBCI). In this thesis, one of LBCI's theoretical variables was tested whether it correlates with empirical data from the pastoral land in Sweden in order to test its ability to make theoretical estimates against the empiric. The variable tested was Biotope Functional Capacity (BFC). It was done by sampling 20 replicates in southern and central Sweden from which empirical data were obtained from pastures through the National Inventory of the Landscape in Sweden (NILS), compiled into four diversity indexes; species richness, Shannon's index, Simpson's index of diversity and Simpson's reciprocal index. Lastly, statistical correlation analyzes were performed which did not show any correlation between the variable and the various diversity indices. Reasons for this may be due to how the empirical data has been analyzed and compiled or deficiencies in the BFC variable. Nevertheless, this study has contributed to important viewpoints in the continued development of the new biodiversity indicator LBCI and method development to further investigate the relationship between the BFC variable and empirical values.