The goal of this 5 credits project was to study the behaviour of the breakdown voltage ofan ATLAS Silicon strip sensor of specification ATLAS12EC. It was investigated wether or nota newly implemented HV-tab bonding procedure would influence the breakdown voltage. Theimpact of reduced humidity on the breakdown voltage was studied by filling the sensor testchamber with Nitrogen gas.To measure the breakdown voltages, IV measurements of the sensor before and after the HV-tab bonding and with and without filling the sensor test chamber with Nitrogen gas wereperformed.Results of this study will be used for qualifying the Uppsala lab for ATLAS production whichrequired a change in the measurement software that had been used previously for IV measure-ments. These software changes were also implemented over the course of this project.

Kraft pulping is the most widely used pulping process for producing chemical pulp today. It has been in use for more than 130 years. During the pulping process most of the lignin and part of the hemicellulose are removed from the wood, resulting in an unbleached chemical pulp which is mainly composed of cellulose, some hemicellulose with smaller amounts of modified lignin. Several studies have been conducted to ensure effective delignification during the kraft cooking process. Nonetheless, due to the highly complex chemistry and anatomy of wood, there is a need to understand pulping chemistry in more detail. The principal inorganic component in wood is calcium. A considerable share of the calcium in wood is released during the chemical pulping process. The calcium released initially during kraft pulping is mainly soluble in cooking liquor which passes through a thermodynamically stable limit before reacting with carbonate to form calcium carbonate. The calcium in the pulping process causes precipitation and scaling problems in the pulping process lines, especially in the black liquor evaporation sections. The focus of this work is to increase the knowledge of kraft cooking of Eucalyptus dunnii which has high calcium content and cooking chemicals reactions during delignification. In addition, the aim was to investigate the influence of different calcium levels in E. dunnii wood chips on the kraft pulping process. Chips with different calcium levels were pulped in lab-scale digesters. The results obtained in this work showed that the rate of delignification decreased and polysaccharide degradation increased during kraft pulping of E dunnii when the calcium content was high. E dunnii with low calcium content showed no adverse effect on the delignification rate and polysaccharide degradation during kraft pulping. The uronic acid content in wood and the hexuronic acid content in pulp after kraft cooking showed no significant impact on the delignification rate. The detrimental effect of calcium during kraft pulping was studied using green liquor introduction in kraft pulping. Using green liquor during the kraft pulping of high calcium E dunni wood chips and extending the impregnation time resulted in good delignification and lower degradation of polysaccharides. Unbleached pulps produced from high calcium content wood could be bleached with good results, i.e., equal brightness and increased strength properties. The drainage resistance of bleached pulp was slightly increased. The calcium present in the wood chips follows the fibre line with the pulp after kraft cooking and is less soluble in kraft black liquor. These phenomena are probably related to the carbonate present in green liquor “inactivating” the adverse effects of calcium ions. Possible scientific mechanisms and hypotheses are discussed in this work. Preliminary studies using industrial green liquor compared to synthetic green liquor on a lab scale are also discussed in this work. Keywords: kraft pulping, delignification, polysaccharide degradation, viscosity, H-factor, kappa number, calcium content / Sammanfattning Sulfatprocessen är idag den mest använda metoden för framställning av kemisk massa, och har varit i användning i mer än 130 år. Under denna process avlägsnas det mesta av ligninet och en del av hemicellulosa från veden, vilket producerar en oblekt kemisk massa främst bestående av cellulosa och en del hemicellulosa med mindre mängder modifierat lignin. Flera studier har fokuserat på effektiv delignifiering under sulfatkoket, men trots detta finns det ännu brister i förståelsen av processen beroende på den komplexa kemin och morfologin hos trä.    Den viktigaste oorganiska kompententen i ved är kalcium. En stor del av detta frigörs under sulfatprocessen. Det som frigörs tidigt under koket är huvudsakligen löst i kokvätskan innan det kan reagera med karbonat och bilda calciumkarbonat.  Kalcium I massakokningsprocesser orsakar problem med utfällningar på utrustningen, särskilt i indunstningssystemet.  Fokuset för detta arbete är att öka kunskapen om sulfatkok av ved från Eucalyptus dunnii med hög kalciumhalt, och kemiska reaktioner under massatillverkningen. Ett vidare mål är att undersöka betydelsen av betydelsen av varierande kalciumhalter i ved från E. dunni. Flis med olika halt av kalcium kokades i labskala.  Resultaten i detta arbete visade att delignifieringshastigheten avtog och polysackaridnedbrytningen tilltog vid högre kalcumhalter i veden. Det var däremot ingen påverkan på hexenuronsyrabildningen. Dessa negativa effekter av hög kalciumhalt kunde minimeras genom närvaro av grönlut Användes grönlut vid massatillverkning av E. dunni ved med hög kalciumhalt. Kunde massatillverkning utföras med tillfredställande delignifiering och låg kolhydratnedbrytning. Massor framställda på detta sätt kunde blekas med gott resultat, d.v.s. hög ljushet och goda styrkeegenskaper. Avvattningsmotståndet var dock något högre. Vid användning av grönlut följer calciumet med massan snarare än hamnar I svartluten. De positiva effekterna av grönlutsanvändning beror troligen på att kalciumjonerna inaktiveras och därmed undvikt negativa effekter av lösligjorda kalciumjoner. Förslag till möjliga mekanismer som förklarar dessa effekter diskuteras i avhandlingen. En jämförelse mellan syntetiska grönlutar och industriella grönlutar presenteras också.    Nyckelord: Sulfatmassaprocessen, delignifiering, polysackaridnedbrytning, viskositet, H-faktor kappatal, kalciumhalt

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Abstract Exploring the Biogeochemical Impacts of Size Variation in Reticulofenestra during the Late Miocene Paul Utuedor Coccolithophores belong to the group of calcifying plankton. They are characterised by the production of calcite platelets called coccoliths. The efficiency of the coccoliths in transporting calcium carbonate into the ocean interior is a factor of their size and abundance. Previous investigations into the evolution of a certain taxonomic group, the reticulofenestrids, have revealed patterns of size variations throughout the Cenozoic. The coccoliths produced by the Reticulofenestra genus typically exhibit a progressive increase in size and a rapid fall in maximum size in Miocene and Pliocene nannofossil assemblages. This project quantified the abundance of Reticulofenestra coccoliths and compared it to the impact of their individual carbonate mass (which is dependent on size and shape) at a North Atlantic deep-sea site during the late Miocene (~5.8 to 10.3 Ma). This research was carried out to determine the efficiency of carbonate export by the Reticulofenestra species during this time. The species of Reticulofenestra are generally classified based on the size of their coccoliths as small (<3 µm), medium (3-5 µm), large (>5- 7 µm), and very large (>7 µm). The most abundant Reticulofenestra group is medium-sized (3-5 μm) and has a low carbonate mass. As a result, they have less significant carbonate flux than expected intuitively from their high abundance, compared to the >7 μm group with a high carbonate mass but low abundance. With an average mass of 69.12 pg, the large-sized group hold eight-fold higher mass per coccolith than the medium-sized coccoliths (average 8.64 pg). Therefore, the coccolith's size impacts carbon export to the ocean floor, affects carbon cycling and, by extension, biogeochemical processes.

Two types of planar defects, phase interface and stacking fault, are addressed in thisthesis. The first-principles exact-muffin orbitals method in combination with thecoherent-potential approximation is the main density functional theory (DFT) toolfor our studies. The investigation is mainly carried out for stainless steels which arefundamental materials in modern society. Ferritic and austenitic stainless steels arethe two largest subcategories of stainless steels.In ferritic stainless steels, the interface between Fe-rich α and Cr-rich α′ phasesformed during spinodal phase decomposition is studied. This decomposition isknow to increase the hardness of ferrites, making them brittle (also called the "475◦ Cembrittlement"). We calculate the interfacial energies between the Cr-rich α′ -Fex Cr1−xand Fe-rich α-Fe1−y Cry phases (0 < x, y < 0.35) and show that the formation energyis between ∼0.02 and ∼0.33 J m−2 for the ferromagnetic state and between ∼0.02and ∼0.27 J m−2 for the paramagnetic state. Although for both magnetic states,the interfacial energy follows a general decreasing trend with increasing x and y,the fine structures of the γ(x, y) maps exhibit a marked magnetic state dependence.The subtleties are shown to be ascribed to the magnetic interaction between the Feand Cr atoms near the interface. The theoretical results are applied to estimate thecritical grain size for nucleation and growth in Fe-Cr stainless steel alloys.In close-packed alloys possessing the face centered cubic crystallographic lattice ,stacking faults are very common planar defects. The formation energy of a stackingfault, named stacking fault energy, is related to a series of mechanical properties.Intrinsic stacking fault energy for binary Pd-Ag, Pd-Cu, Pt-Cu and Ni-Cu solid so-lutions are calculated using the axial interaction model and the supercell model. Bycomparing with experimental data, we show that the two models yield consistentformation energies. For Pd-Ag, Pd-Cu and Ni-Cu, the theoretical SFEs agree wellwith those from the experimental measurements. For Pt-Cu no experimental resultsare available, and thus our calculated SFEs represent the first reasonable predictions.We also discuss the correlation of the SFE and the minimum dmin in severe plasticdeformation experiments and show that the dmin values can be evaluated from firstprinciples calculations.After gaining confidence with the axial interaction model, the alloying effects of Mn,Co, and Nb on the stacking fault energy of austenitic stainless alloys, Fe-Cr-Ni withvarious Ni content, are investigated. In the composition range (cCr = 20%, 8 ≤cNi ≤ 20%, 0 ≤ cMn , cCo , cNb ≤ 8%, balance Fe) studied here, it is found that Mndecreases the SFE at 0 K, but at room temperature it increases the SFE in high-Ni (cNi16%) alloys. The SFE always decreases with increasing Co. Niobiumincreases the SFE significantly in low-Ni alloys, however this effect is strongly di-minished in high-Ni alloys. The SFE-enhancing effect of Ni usually observed inFe-Cr-Ni alloys is inverted to SFE-decreasing effect in the hypothetical alloys con-taining more than 3% Nb in solid solution. The revealed nonlinear compositionivdependencies are explained in terms of the peculiar magnetic contributions to thetotal SFE. / QC 20120426

Efficient early warning systems can help in the management of natural disaster events, by allowing for adequate evacuations and resources administration. Several approaches have been used to implement proper early warning systems, such as simulations or statistical models, which rely on the collection of meteorological data. Data-driven techniques have been proven to be effective to build statistical models, being able to generalise to unseen data. Motivated by this, in this work, we explore deep learning techniques applied to the typhoon meteorological satellite image dataset "Digital Typhoon".  We focus on intensity measurement and categorisation of different natural phenomena. Firstly, we build a classifier to differentiate natural tropical cyclones and extratropical cyclones and, secondly, we implement a regression model to estimate the centre pressure value of a typhoon. In addition, we also explore cleaning methodologies to ensure that the data used is reliable. The results obtained show that deep learning techniques can be effective under certain circumstances, providing reliable classification and regression models and feature extractors. More research to draw more conclusions and validate the obtained results is expected in the future. / Effektiva varningssystem kan hjälpa till med hanteringen av naturkatastrofer genom att möjliggöra tillräckliga evakueringar och resursfördelningar. Flera olika tillvägagångssätt har använts för att genomföra lämpliga tidiga varningssystem, såsom simuleringar eller statistiska modeller, som bygger på insamling av meteorologiska data. Datadriven teknik har visat sig vara effektiv för att bygga statistiska modeller som kan generalisera till okända data. Motiverat av detta, utforskar examensarbetet tekniker baserade på djupinlärning, vilka tillämpas på ett dataset med meteorologiska satellitbilder, Digital Typhoon".  Vi fokuserar på intensitetsmätning och kategorisering av olika naturfenomen.  Först bygger vi en klassificerare för att skilja mellan naturliga tropiska cykloner och extratropiska cykloner. Därefter implementerar vi en regressionsmodell för att uppskatta en tyfons mittrycksvärde. Dessutom utforskar vi rengöringsmetoder för att säkerställa att de data som används är tillförlitliga.  De erhållna resultaten visar att tekniker för djupinlärning kan vara effektiva under vissa omständigheter, vilket ger tillförlitliga klassificerings- och regressionsmodeller samt extraktorer. Mer forskning för att dra fler slutsatser och validera de erhållna resultaten förväntas i framtiden. / Els sistemes d’alerta ràpida poden ajudar en la gestió dels esdeveniments de desastres naturals, permetent una evacuació i administració dels recursos adequada. En aquest sentit s’han utilitzat diferentes tècniques per implementar sistemes d’alerta, com ara simulacions o models estadístics, tots ells basats en la recollida de dades meteorològiques. S’ha demostrat que les tècniques basades en dades són eficaces a l’hora de construir models estadístics, podent generalitzar-se a a noves dades. Motivat per això, en aquest treball, explorem l’ús de tècniques d’aprenentatge profund (o deep learning) aplicades a les imatges meteorològiquesper satèl·lit de tifons del projecte "Digital Typhoon". Ens centrem en la mesura i la categorització de la intensitat de diferentsfenòmens naturals. En primer lloc, construïm un classificador per diferenciar ciclonstropicals naturals i ciclons extratropicals i, en segon lloc, implementemun model de regressió per estimar el valor de pressió central d’un tifó.A més, també explorem metodologies de neteja per garantir que lesdades utilitzades siguin fiables. Els resultats obtinguts mostren que les tècniques d’aprenentatgeprofundes poden ser efectives en determinades circumstàncies, proporcionant models fiables de classificació/regressió i extractors de característiques.Es preveu que hi hagi més recerques per obtenir més conclusions i validar els resultats obtinguts en el futur.

The work in this thesis has been focused on developing surfaces for use in biosensor systems, especially for quartz crystal microbalances. The surfaces were prepared by adsorption of organosulfur molecules onto gold substrates, so called self assembled monolayers (SAMs). By chemical synthesis these thiols can be specifically tailored to provide surfaces with desired properties. The investigated surfaces were all based on thiols terminated with carboxylic acid groups to render hydrophilic surfaces onto which desired proteins can be covalently attached. In order to increase the performance of two dimensional carboxyl surfaces, a method for improving the immobilization of proteins to the surface was investigated. The immobilization levels of antibodies were increased by using N-hydroxysulfo-succinimide (sulfo-NHS), instead of N-hydroxy-succinimide (NHS), as stabilizer of the amine reactive intermediate formed by reaction of the carboxyl groups with 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). The negatively charged sulfo-NHS intermediate promotes the attraction of overall positively charged proteins and enables immobilization also at low pH. In addition, the orientation of the immobilized antibodies was shown to be dependent on the pI of the antibody and to have a profound effect on the subsequent interaction with the antigen. The organization of carboxyl terminated SAMs can be poor due to the repellation between the polar terminal groups. By using acidified ethanol as solvent during the assembly step of monolayer formation, the organization in carboxyl terminated alkyl and oligo(ethylene glycol) SAMs was improved. However, the carboxyl groups were found to be converted to ethyl esters, the rate being related to the acid strength. Furthermore, the long-term stability of carboxyl oligo(ethylene glycol) SAMs was investigated. Here, the effect of alkyl chain length on the storage stability was of interest. A short alkyl chain was shown to have a profound negative effect on the storage stability of the SAM, resulting in decomposition and loss of functionality over time compared to when thiols with longer alkyl chains were studied. / <p>In publication incorrect ISBN: 9879173935876</p>

<p>2023-06-11</p>

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