| 1. |
- Goetz, Inga Katharina, 1992-
(författare)
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Local structure and composition : in additively manufactured bulk metallic glasses and composites
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Additive manufacturing enables the production of complex multi-material geometries and bulk metallic glass parts beyond their critical casting thickness. The local modification of structure, composition, and properties is explored in this thesis with the aim to design novel composite materials and functional gradients. The present work contributes to the process understanding required to produce bulk metallic glass composites in the laser powder bed fusion process. The investigated material systems include zirconium and iron based metallic glasses, metallic glass - nitride composites, as well as laser nitriding of titanium.The onset of devitrification of metallic glasses due to the processing or post-processing heat treatments induces the formation of nanoscale clusters. Features of > 1 nm can be detected and reliably distinguished from random fluctuations by atom probe tomography. The progression of crystallisation depends on the oxygen content of the samples and the applied heating or cooling rates. In-depth understanding of the crystallisation processes can be used to optimise both compositions and processing conditions. The process atmosphere contains reactive species such as oxygen or nitrogen, which can be incorporated during different stages of processing by surface oxidation of the powder or substrate pieces as well as by reactions with the gas during processing. While an inert gas atmosphere with a low residual oxygen content is sufficient to hinder reactions with residual oxygen, a nitrogen atmosphere can be used for local laser nitriding and, thus, the fabrication of metallic glass – ceramic composites. Due to the decompositions of nitrides formed in the preceding process steps and the tendency of a metallic glass matrix to crystallise, which limits the processing conditions, the incorporation of nitrogen is restricted to the first few hundred nm from the surface for a Zr-based amorphous alloy. In titanium, as a crystalline example, nitrogen is incorporated throughout the molten pool.The nitride composites exhibit increased hardness depending on the local nitride fraction, which can thus be used to fabricate specific property gradients within or on a printed piece. With optimised process parameters, the amorphous fraction of a printed Fe-based bulk metallic glass can be tailored for improved soft magnetic properties.
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| 2. |
- Gribenski, Natacha, 1986-
(författare)
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Comparison of dating methods for paleoglacial reconstruction in Central Asia
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Reconstruction of former Central Asian glaciers extents can provide valuable information about past atmospheric circulation variations. These extents, often marked by terminal moraines, need to be chronologically constrained. Cosmogenic nuclide exposure (CNE) dating is widely used to directly date moraines. In addition, there is increasing interest on using optically stimulated luminescence (OSL) techniques for dating glacial landforms. This thesis focuses on the methodological aspects of directly dating glacial landforms to perform paleoglacial reconstructions in Central Asia, with an emphasis on OSL dating.For OSL dating of sediments from glacial settings, it is important to measure the luminescence signal at the single grain scale, because the sediments are likely affected by partial bleaching due to short light exposure during glacial or glaciofluvial transport. The use of an Electron Multiplying Charges Coupled Device (EMCCD)-based imaging system for single grain OSL measurements would offer larger flexibility in light stimulation and sediment type, compared to the current Single Grain Risø reader. An automated image processing procedure has been developed to compensate for sample carrier displacement over repeated measurements and for attributing pixels to each grain for signal integration when using this imaging system. However, significant cross talk contamination, demonstrated by laboratory and simulation experiments, prohibits accurate single grain luminescence measurements. Preliminary experiments using a basic image processing algorithm show good potential for software correction solutions.Paleoglacial reconstructions conducted in the Altai Mountains, Central Asia, using both CNE and OSL dating demonstrate that luminescence measurements of glaciofluvial sediments performed at the multi-grain scale result in large age overestimates, and that single grain measurements allow for more accurate dating of glacial landforms. However, uncertainties remain that are related to the model used for extracting equivalent doses for well-bleached grains and to fading corrections when using feldspar minerals. The timing of glaciation can be inferred from scattered CNE moraine boulder ages if most of the ages are concentrated within a few thousand years, with only few ages clearly older or younger. Overall, combining CNE and OSL techniques for dating a glacial landform is a powerful approach for producing robust glacial chronologies, despite uncertainties inherent to each technique.Paleoglacial reconstructions from the Altai Mountains indicate Marine Isotope Stage (MIS) 2 and MIS 4/late MIS 5 local Last Glacial Maximums. In Central Asia, in addition to a regional MIS 2 glaciation, previous studies indicate a period of major glacial advances during MIS 3 that is out of phase with global ice volume records. However, most MIS 3 glacial chronologies from Central Asia are based on too few or too heavily scattered CNE data sets, or on OSL or Electron Spin Resonance (ESR) ages for which partial bleaching has not been properly investigated. Hence, at this stage, chronological evidence is insufficient to demonstrate a regional MIS 3 glaciation in Central Asia.Surge-related glacial features identified in the Russian Altai also highlight the importance of conducting detailed geomorphology and sedimentology studies to understand former ice dynamics, which is essential for inferring appropriate paleoclimate information from paleoglacial reconstructions.
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| 3. |
- Hammarström, Per, 1960-
(författare)
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Nationens styvbarn : Judisk samhällsintegration i några Norrlandsstäder 1870-1940
- 2007
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Ingår i: Svensk kyrkotidning. - Stockholm : Carlsson Bokförlag. - 0346-2153. ; :51-52, s. 664-
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med denna avhandling är att undersöka vilken ekonomisk och social ställning den judiska minoriteten intog i det svenska samhället under perioden 1870 till 1940. Tidigare forskning har riktat stor uppmärksamhet mot rättsliga och politiska aspekter av den svenska judenhetens historia, mer sällan mot judarna och samhället i en bredare bemärkelse. Andra studier har lyft fram antisemitism på svensk mark utan att koppla fenomenet till en social nivå.Genom en undersökning av hur judiska invandrare, med ursprung i Östeuropa, successivt fogades in i några svenska lokalsamhällen, tar denna avhandling ett bredare grepp på frågan om judarna och samhället. Här undersöks hur den svenska judenheten integrerades i samhället efter det att emancipationen gett judarna fulla medborgerliga och politiska rättigheter. Judarnas ekonomiska och sociala ställning undersöks, liksom den sociala antisemitism som drabbade judarna. Studien rör sig i gränslandet mellan social- och kulturhistoria. Undersökningen visar att merparten av judarna i Sundsvall, en betydelsefull handelsstad i norra Sverige, fick sin försörjning genom en föga lönsam gårdfarihandel under början av undersökningsperioden. Sedan butiks- och grosshandelsrörelser började grundas inleddes en långsam socioekonomisk klättring. I takt med de ekonomiska framgångarna ökade judarnas sociala status, med engagemang i föreningslivet och lokalpolitiken. De framgångsrika familjerna tonade ner sin judiska identitet till förmån för en borgerlig och nationell kultur.Ungefär hälften av den judiska gruppen fick aldrig uppleva framgången utan förblev en marginaliserad grupp, med småhantverk eller gårdfarihandel som försörjningsbas. Det stora flertalet av denna underklass saknade svenskt medborgarskap. En social klyfta vidgades gentemot den judiska borgerligheten. Under hela undersökningsperioden var antisemitismen en kulturell kod i majoritetssamhället, oavsett integration och socioekonomisk framgång. Mycket tyder på att det sociala klimatet blev mer fientligt gentemot judarna efter 1920. Studien visar att nationalstaten Sverige lämnade litet utrymme för multikulturella strukturer. Judarna accepterades som nationens styvbarn men knappast som fullvärdiga svenskar.
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| 4. |
- Hessérus, Mattias, 1977-
(författare)
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Rätten till privatlivet : och moralen bakom omoralen i svensk press 1920 – 1980
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis examines the development of the notion of the right to privacy in Sweden between 1920 and 1980. The formation of the notion of the right to privacy is studied through the debate concerning exposure of the aspect of privacy that can be considered the most sensitive: the individual’s sex life and intimate relations.The theoretical framework is based on the sociologist Ferdinand Tönnies’ concepts of Gemeinschaft and Gesellschaft (community and association). The thesis pays particular attention to privacy in relation to the development of the “media society” during the 20th century.Three significant shifts in the Swedish history of privacy during the 20th century are identified and examined: The boycott of the muck-raking paper Fäderneslandet (“The Fatherland”) in 1927, the introduction of “the sanctity of private life” in the rules of the Swedish Publicists’ Association in 1953 and the appointment of the Integrity Protection Committee in 1966.Key findings are: The notion of right to privacy in Sweden evolves in four phases: The first phase (1920 – 1953) is characterized by a paradoxical relationship to privacy following the division between “decent” and “indecent”. “Decent people” had the right to a private sphere while “indecent people” were deprived of privacy. After a viscous hunt of homosexuals in the press, in the late 1940’s, the second phase (1953 – 1964) is defined by liberalisation of the decency concept and a more restrictive press policy as regards exposure of private details relating to sexuality.A modern-day notion of right to privacy is, however, not visible in Sweden until the third phase (1964 – 1975). Yet, the fourth phase (1975 – 1980) is characterised by a backlash. Under the slogan of “the private is political” young radicals and second-wave feminists questioned the privacy concept and saw the right to privacy as a threat to community and equality. Attempts to create privacy legislation in Sweden failed due to unwillingness by the government to recognize the rights of the individual over the rights of the community.Conflicting notions of Gemeinschaft and Gesellschaft within society partly explains the shifting status of the right to privacy in Sweden 1920 – 1980.
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| 5. |
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| 6. |
- Jansson, Anette M, 1963
(författare)
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Effects of Steel Fibres on Cracking in Reinforced Concrete
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- ABSTRACTAlthough it is well known that fibre reinforcement acts as a crack arresting agent, there is still a need for deeper knowledge of the actual cracking behaviour, especially regarding cracks with widths smaller than 0.3mm. Today major fibre applications are as a replacement for the welded mesh in industrial floors, and as reinforcement in sprayed concrete. However, other applications exist and are investigated.By combining experiments with finite-element analyses, the effects of fibres on cracking in conventionally reinforced, self-compacting, steel-fibre-reinforced concrete (SCSFRC) were studied. When studying the beginning of the cracking process, the tensile softening behaviour (-w relationship), and the bond stress-slip behaviour, which are the ones mainly affecting the cracking, are clearly of interest. Contradictory information on the effect of fibres on bond behaviour was found in the literature. Pull-out tests with short embedment length were thus carried out. The -w relationship may be obtained indirectly by inverse analysis, e.g. from wedge-splitting tests, or directly, from uniaxial tension tests (UTT); both approaches were used in this work. To investigate the cracking process, tension tests of tie elements were carried out, where, in addition to the load-deformation curves, a full-field strain measuring technique using Digital Image Correlation (DIC) was used to monitor the surface cracking.It was found from the pull-out tests that, for the type and amount of fibres used here, the bond properties at the interface layer were neither reduced nor improved. There were indications, however, that the initial stiffness of the bond stress-slip curves was increased by the self-compacting concrete. The UTT and the tie element testing showed that the scatter was quite high regarding the number of fibres in a cut cross section. It was seen that fibre reinforcement markedly improves tension stiffening and, at a given load, the characteristic crack width is greatly reduced compared with plain concrete. The DIC gave good insight into the surface crack initiation and enabled the tension stiffening to be quantified by relating it to the characteristic crack widths. In addition, it was seen that the cracking load and first-peak tensile stress increased with an increasing amount of fibres.The Finite element analyses of the beams and the tie elements revealed that the methodology used was versatile. It was found that the smeared crack model did not yield crack localization for materials with high fibre content (Vf > 0.5%) if homogenous material properties were assumed. Instead a semi-meso approach was used; properties for plain concrete were assigned to randomly designated parts of the elements, while the remaining elements were assigned modified tensile properties. The modified properties were increased so that the average -w curve of one cross section corresponded to the average curve from the UTT. With the new approach, the load-elongation response agreed better with the experiments; crack localization was obtained and crack widths could be reasonably reproduced.
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| 7. |
- Jansson, Anna M
(författare)
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Inflammatory markers and prognosis in acute coronary syndromes
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Inflammation both accelerates atherosclerosis and contributes to the activation and rupture of the atherosclerotic plaque. Several markers of inflammation, such as CRP, have shown prognostic merit in patients with acute coronary syndromes (ACS). Aims: To investigate the association between circulating levels of some markers with relation to inflammation – osteoprotegerin (OPG), Chemokine (C-X-C motif) ligand 16 (CXCL16) and chromogranin A (CgA) – and prognosis in a population of patients with ACS. Material and methods: Patients aged 18-79 years who were admitted to the coronary care unit at a university hospital with an ACS had blood drawn within 24 hours and after 3 months; echocardiography with determination of the left ventricular ejection fraction (LVEF) was performed within 5 days of admission. Mortality data were obtained from the Swedish National Population Registry and morbidity data from the Swedish Hospital Discharge Registry. The length of follow-up was a median of 81-92 months. Results: Higher OPG levels were associated with an increased likelihood of ST-elevation myocardial infarction (MI), markers of myocardial damage and indices of cardiac dysfunction such as LVEF and B-type natriuretic peptide (BNP). The patients with the higher levels were also more likely to have a history of heart failure (HF) and to be hypotensive on arrival. The circulating OPG levels were predictive of long-term mortality and the incidence of rehospitalization due to HF, a relationship that remained significant after adjustment for clinical risk factors and, in a subgroup where such data were available, after further adjustment for LVEF, CRP, BNP and troponin. The C-statistics of the prognostic information offered by OPG were significantly better than CRP and troponin and similar to BNP and LVEF. For CXCL16, as for OPG, higher levels were associated with higher age and STEMI. CXCL16 predicted long-term mortality, future hospitalizations for HF and new MI, also after adjustment for clinical risk factors. After further adjustments for LVEF, CRP, proBNP and troponin, only the combination of OPG and CXCL16 serum levels predicted cardiovascular (CV) and all-cause mortality, as well as HF rehospitalizations. This was true for both the long term and short term, even after adjustment for the Global Registry of Acute Coronary Events (GRACE) score. Serum levels of OPG and CXCL16 at day 1 and 3 months after ACS were similarly associated with outcome. CgA was also an independent predictor of mortality and HF after adjustments for conventional risk factors, including troponin, and was still significantly associated with mortality after further adjustment for LVEF and proBNP. Conclusions: Even after adjustment for conventional risk markers, serum levels of OPG, CXCL16 and CgA were predictive of long-term mortality and rehospitalizations due to HF in patients with ACS. We also found that a combination of OPG and CXCL16 serum levels was predictive of mortality and HF hospitalizations - and gave more information than each marker alone - in both the long term and the short term, even after adjustment for the GRACE score. Inflammatory markers appear to add prognostic value above and beyond clinical information.
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| 8. |
- Jansson, Anna M., 1979-
(författare)
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Targeting Infectious Disease : Structural and functional studies of proteins from two RNA viruses and Mycobacterium tuberculosis
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The recent emergence of a number of new viral diseases as well as the re-emergence of tuberculosis (TB), indicate an urgent need for new drugs against viral and bacterial infections.Coronavirus nsp1 has been shown to induce suppression of host gene expression and interfere with host immune response. However, the mechanism behind this is currently unknown. Here we present the first nsp1 structure from an alphacoronavirus, Transmissible gastroenteritis virus (TGEV) nsp1. Contrary to previous speculation, the TGEV nsp1 structure clearly shows that alpha- and betacoronavirus nsp1s have a common evolutionary origin. However, differences in conservation, shape and surface electrostatics indicate that the mechanism for nsp1-induced suppression of host mRNA translation is likely to be different in the alpha- and betacoronavirus genera.The Modoc virus is a neuroinvasive rodent virus with similar pathology as flavivirus encephalitis in humans. The flaviviral methyltransferase catalyses the two methylations required to complete 5´ mRNA capping, essential for mRNA stability and translation. The structure of the Modoc NS5 methyltransferase domain was determined in complex with its cofactor S-adenosyl-L-methionine. The observed methyltransferase conservation between Modoc and other flaviviral branches, indicates that it may be possible to identify drugs that target a range of flaviviruses and supports the use of Modoc virus as a model for general flaviviral studies.1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) is part of the methylerythritol phosphate (MEP) pathway that produces essential precursors for isoprenoid biosynthesis. This pathway is used by a number of pathogens, including Mycobacterium tuberculosis and Plasmodium falciparum, but it is not present in humans. Using a structure-based approach, we designed a number of MtDXR inhibitors, including a novel fosmidomycin-analogue that exhibited improved activity against P.falciparum in an in vitro blood cell growth assay. The approach also allowed the first design of an inhibitor that bridge both DXR substrate and co-factor binding sites, providing a stepping-stone for further optimization.
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| 9. |
- Jansson, Peter M., 1965-
(författare)
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Våldets onda cirklar : En explorativ undersökning av mäns barndomsupplevelser, maskuliniteter, känslor, våld samt terapeutiska interventioner mot våld
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Avhandlingens överordnade syfte är att utforska möjligheterna för ett integrerat forskningsperspektiv på mäns våld samt exemplifiera hur sådan forskning kan bedrivas. Det konkreta syftet är att öka kunskapen om hur våldsamma mäns barndomsupplevelser, socialisation, maskulinitetskonstruktion och emotioner kan relateras till deras våld mot andra män, mot sig själva och mot kvinnor samt till hur terapeutiska interventioner mot våld kan analyseras och utvecklas i korrespondens med denna kunskap. Med vetenskapsteoretiska utgångspunkter hämtade från den kritiska realismen och ekologiska metoder relaterar studien forskning från olika skolbildningar till varandra; - psykologisk: om barndomserfarenheter och socialisation, socialpsykologisk: om emotioner och interaktion samt sociologisk: om social klass, könsmaktsstrukturer och hegemonisk maskulinitet. Detta genomförs för att kunna få tillgång till kunskap om hur olika faktorer samverkar vid mäns våld.I studie I och II studerades möjligheterna att undersöka de sociala banden mellan terapeut/terapi och klient inom terapeutiska behandlingar mot våld. I studie I operationaliserades indikatorer på emotionerna stolthet och skam och i studie II testades dessa på terapeuter inom en KBT-orienterad terapi. I studie IIIundersöktes män i olika maskulinitetspositioner, där urvalet för den ena gruppen hämtades ur populationen män dömda till terapi för våld och missbruk och den andra ur populationen män som organiserat arbetade för jämlikhet och mot våld mot kvinnor. I studien jämfördes de båda gruppernas förhållningssätt till faktorer som i tidigare forskning relaterats till våld och våld mot kvinnor. I studie IVundersöktes våldsdömda mäns karriärer fram till deras nuvarande position som våldsbejakande kriminella i avsikt att öka kunskapen om det samspel mellan faktorer som i olika situationer leder fram till deras våld mot andra män, sig själva och kvinnor. Samtliga empiriska studier använde kvalitativa metoder för datainsamling och analys. I studie IV användes individuella intervjuer och biografisk analys, I studie II ochIII användes gruppintervjuer samt deduktiv innehållsanalys. I studie I, den teoretiska reviewartikeln, utgjorde sociologisk, socialpsykologisk och psykologisk teoribildning empiri.Avhandlingen visar att det finns fler fördelar är nackdelar med ett nivåövergripande perspektiv. Nivåintegrerande studier försvåras av att de kräver en komplex metodologi för att kunna hantera samverkan mellan faktorer bakom våld på olika nivåer men ger å andra sidan en mer holistisk förståelse av fenomenet i fråga. Resultaten visar att integrerande perspektiv kan minska risken för ekologiska felslut och ökar förståelsen av komplex samverkan mellan faktorer bakom mäns våld, något som kan komma att bidra till kunskapsutvecklingen inom våldsterapiområdet. Den teoretiska reviewartikeln (studie I) exemplifierade hur teoretiskt och metodologiskt driven forskning om sociala band kan göras pragmatiskt tillämpbar av terapeuter inom våldbehandlingar. Den tillämpade studien av en KBT-terapi (studie II) gav exempel på hur operationaliserade indikatorer på stolthet och skam kan användas praktiskt för att bestämma kvalitén på det sociala bandet mellan terapeut och klient. Den studerade KBT-terapin innehöll som förväntat både skam- och stolthetskapande moment vilket utgör värdefulla utgångspunkter för vidare forskning. Jämförelsen mellan män i idealtypiskt motsatta maskulinitetspositioner (studie III) visade att både gruppen av män som arbetar mot våld mot kvinnor och männen dömda till behandling mot våld, bär på ambivalenta attityder gentemot våld och våld mot kvinnor. Jämförelsen visade vidare att gruppernas maskulinitetskonstruktioner och attityder till våld korresponderar med grupperingarnas olika tillgång till ekonomiska, sociala och kulturella resurser. Den biografiskt fokuserade kvalitativa studien av män i våldsbehandling (studie IV) undersökte explorativt hur karriären fram till våldskriminell kan se ut och hur barndomsupplevelser, socialisation, maskulinitet och emotioner hos enskilda våldsverkande män kan tänkas ha samverkat med varandra när våld äger rum. Resultaten visade att de män som vittnar om utsatthet för allvarligt våld i barndomen är mer skambenägna och vid kränkningar från andra tenderar att omedvetet och utan föregående känslor av skam direkt reagera med aggressioner och våld mot båda könen. Övriga män var visserligen skambenägna men beskrev en mer kontrollerad våldsreaktion. Två män som blivit brutalt fysiskt mobbade i grundskolan, berättade om ett mer kontrollerat våld. En preliminär hypotes är att männen kan ha lärt sig att kognitivt, för att undslippa fortsatt mobbing, ta kontrollen över processen där skamkänslor ersätts med aggressioner. Föräldrarnas personliga problem tillsammans med deras bristande sociala kontroll och omsorg antogs ha ett samband med flera av männens skolproblem, deras umgänge med avvikande ungdomar, deras senare svårigheter med att kunna försörja sig med konventionella medel samt deras våldskarriärer.
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| 10. |
- Juston, John M., 1960-
(författare)
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Environmental Modelling : Learning from Uncertainty
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Environmental models are important tools; however uncertainty is pervasive in the modeling process. Current research has shown that understanding and representing these uncertainties is critical when decisions are expected to be made from the modeling results. One critical question has become: how focused should uncertainty intervals be with consideration of characteristics of uncertain input data, model equation representations, and output observations? This thesis delves into this issue with applied research in four independent studies. These studies developed a diverse array of simply-structured process models (catchment hydrology, soil carbon dynamics, wetland P cycling, stream rating); employed field data observations with wide ranging characteristics (e.g., spatial variability, suspected systematic error); and explored several variations of probabilistic and non-probabilistic uncertainty schemes for model calibrations. A key focus has been on how the design of various schemes impacted the resulting uncertainty intervals, and more importantly the ability to justify conclusions. In general, some uncertainty in uncertainty (u2) resulted in all studies, in various degrees. Subjectivity was intrinsic in the non-probabilistic results. One study illustrated that such subjectivity could be partly mitigated using a “limits of acceptability” scheme with posterior validation of errors. u2 was also a factor from probabilistic calibration algorithms, as residual errors were not wholly stochastic. Overall however, u2 was not a deterrent to drawing conclusions from each study. One insight on the value of data for modeling was that there can be substantial redundant information in some hydrological time series. Several process insights resulted: there can be substantial fractions of relatively inert soil carbon in agricultural systems; the lowest achievable outflow phosphorus concentration in an engineered wetland seemed partly controlled by rapid turnover and decomposition of the specific vegetation in that system. Additionally, consideration of uncertainties in a stage-discharge rating model enabled more confident detection of change in long-term river flow patterns.
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