This licentiate thesis mainly reports about the behavior of arc evaporated TiAlN at high pressures and high temperatures. The extreme conditions have been obtained in metal cutting, multi anvil presses or diamond anvil cells. Several characterization techniques have been used, including x-ray diffraction and transmission electron microscopy. Results obtained during metal cutting show that the coatings are subjected to a peak normal stress in the GPa region and temperatures around 900 °C. The samples after metal cutting are shown to have a stronger tendency towards the favorable spinodal decomposition compared to heat treatments at comparable temperatures. We have also shown an increased anisotropy of the spinodally decomposed domains which scales with Al composition and results in different microstructure evolutions. Furthermore, multi anvil press and diamond anvil cell at even higher pressures and temperatures (up to 23 GPa and 2200 °C) also show that the unwanted transformation of cubic AlN into hexagonal AlN is suppressed with an increased pressure and/or temperature.

This Thesis explores amorphous transition metal nitrides for cutting tool applications. The aim is to extend the knowledge on amorphous nitride thin lms, to describe the growth process, and to explore ways of characterizing these novel complex materials. Thin lms of Ti-Al-Si-N and Hf-Al-Si-N were fabricated using industrial cathodic arc evaporation and magnetically-unbalanced reactive magnetron sputtering, respectively. The microstructure of the lms was studied using x-ray diraction (XRD) and transmission electron microscopy (TEM), while compositional analysis of the lms was performed by spectroscopic techniques (EDS, SIMS, and RBS). The mechanical properties were investigated by nanoindentation. The Ti-Al-Si-N lms were grown on cemented carbide substrates using Ti-Al-Si compound cathodes in an N2 atmosphere. High Al and Si concentrations in the lms (i.e., 12 at% Si and 18 at% Al) promote renucleation and result in x-ray amorphous lms. High resolution TEM (HRTEM) reveals isolated grains, ~2 nm in size, embedded in an amorphous matrix. Annealing experiments show that the lms are thermally stable up to 900 oC. They exhibit age hardening, with an increase in hardness from 21.9 GPa for as-deposited lms to 31.6 GPa at 1000 oC. At 1100 oC severe out-diusion of Co and W from the substrate occurs, and the lms recrystallize into c-TiN and w-AlN. The single layer Hf-Al-Si-N and multilayer Hf-Al-Si-N/HfN lms were grown on Si(001) substrates from a single Hf0:60Al0:20Si0:20 alloy target in an N2/Ar atmosphere. The composition and nanostructure of the lms was controlled during growth by independently varying the ion energy (Ei) and the ion-to-metal flux ratio (Ji=JMe). With Ji/JMe=8, the nanostructure and composition of the lms changes from x-ray amorphous with a Hf content of 0.6, to an amorphous matrix with encapsulated nanocrystals with 0.66≤Hf≤0.84, to nanocrystalline with 0.96≤Hf≤1.00, when increasing Ei from 15 to 65 eV. Varying Ji=JMe with Ei=13 eV yields electron-diraction amorphous lms at substrate temperatures of 100 oC. Hf-Al-Si-N/HfN multilayers with periods Λ=2-20 nm exhibit enhanced fracture toughness compared to polycrystalline VN, TiN, and Ti0:5Al0:5N reference samples; multilayer hardness values increase from 20 GPa with Λ=20 nm to 27 GPa with Λ=2 nm. ̴

Thermoelectric devices are one of the promising energy harvesting technologies, since they can convert heat (i.e. a temperature gradient) to electricity. This result leads us to use them to harvest waste heat from heat engines or in power plants to generate usable electricity. Moreover, thermoelectric devices can also perform cooling. The conversion process is clean, with no emission of greenhouse gases during the process. However, the converting efficiency of thermoelectrics is very low because of the materials limitations of the thermoelectric figure of merit (ZTm). Thus, there is high demand to maximize the ZTm. I have discovered that ScN has high power factor 2.5 mW/(mK2) at 800 K, due to low metalliclike electrical resistivity (∼3.0 μΩm) with retained relatively large Seebeck coefficient of -86 μV/K. The ScN thin films were grown by reactive dc magnetron sputtering from Sc targets. For ScN, X-ray diffraction, supported by transmission electron microscopy, show that we can obtain epitaxial ScN(111) on Al2O3(0001). We also reported effects on thermoelectric properties of ScN with small changes in the composition with the power factor changing one order of magnitude depending on e.g. oxygen, carbon and fluorine content which were determined by elastic recoil detection analysis. The presence of impurities may influence the electronic density of states or Fermi level (EF) which could yield enhancement of power factor. Therefore, the effects of defects and impurities on the electronic density of states of scandium nitride were investigated using first-principles calculations with general gradient approximation and hybrid functionals for the exchange correlation energy. Our results show that for Sc and N vacancies can introduce asymmetric peaks in the density of states close to the Fermi level. We also find that the N vacancy states are sensitive to total electron concentration of the system due to their possibility for spin polarization. Substitutional point defects shift the Fermi level in the electronic band according to their valence but do not introduce sharp features. The energetics and electronic structure of defect pairs are also studied. By using hybrid functionals, a correct description of the open band gap of scandium nitride is obtained, in contrast to regular general gradient approximation. Our results envisage ways for improving the thermoelectric figure of merit of ScN by electronic structure engineering through stoichiometry tuning and doping.

<p>Betyg 20200605.</p>

Det pågår ett globalt och nationellt arbete med att minska matsvinn med 50 procent i alla livsmedelskedjans led till år 2030. I Sverige står konsumtionsledet för den största produktionen av matsvinn. Skolor och äldreomsorg ingår i konsumentledet och där görs sedan 2017 mätningar av svinn. Denna uppsats är ett samarbete med Hallsbergs kommun som ville ha hjälp med att klimatberäkna matsvinnet från grundskolan och äldreomsorgen för att få en bättre uppfattning av sina maträtters klimatavtryck. Resultaten visar att det var mest svinn inom äldreomsorgen där serveringssvinnet var det största problemet, men även inom skolan var serveringssvinnet större än tallrikssvinnet. Detta ligger i linje med tidigare forskning som också pekar på att serveringssvinnet är det som är störst inom offentliga måltider. De maträtter som innehåller nötkött gav störst klimatavtryck både som rätt och på grund av sitt svinn. På grund av svinnet förlorar kommunen i snitt 2,50 kr i äldreomsorgen och 1,25 kr i skolan. I äldreomsorgen får de ätande i sig i snitt 254 kilokalorier mindre än vad som är rekommenderat vilket kan utgöra en risk för de äldres hälsa, detta bör utredas vidare. För att nå det nationella och globala målet med att halvera matsvinnet till år 2030 behöver Hallsbergs kommun utreda hur de ska komma tillrätta med serveringssvinnet och dessutom se över förekomsten av nötkött på menyn.

Konsumenter och producenter har glidit längre ifrån varandra i samband med tillväxten av det globaliserade livsmedelssystemet. En ökad oro om vad maten innehåller och hur den produceras har fått fler konsumenter att vilja köpa lokalproducerade livsmedel i Sverige. Men begreppet lokalproducerat används i olika syften och förutom avståndsfaktorn följer en rad olika förväntningar om innebörden. En litteraturstudie har utförts för att kartlägga vilka förväntningar och faktorer som kopplas samman med begreppet och för att ta reda på om dessa kan bidra till att nå miljömål i Agenda 2030.  Resultatet visar att konsumenter förväntar sig, förutom ett nära avstånd, att lokalproducerade livsmedel är producerat småskaligt, mindre intensivt, med användandet av lokala sorter och insatsvaror samt anpassat utefter lokala förhållanden. Om dessa förväntningar inkluderas i definitionen på lokalproducerat kan det bidra till att nå flera delmål i Agenda 2030. Resultatet visar också att det sociala mötet mellan konsument och producent som sker i samband med försäljning av lokalproducerat kan påverka hållbarheten i jordbruket och därmed målen i Agenda 2030. På grund av begreppets flexibla användning finns en risk att konsumenter inte får det de förväntar sig när de köper lokalproducerat. Samtidigt väger fördelarna tungt och begreppets olika tolkningar kan representera ett motstånd till dagens livsmedelsystem. Studien påvisar att det antingen kan finnas behov av tydligare definitioner eller så kan begreppet användas för att representera ett ställningstagande. Det vore intressant med mer forskning för att kunna koppla samman förväntningarna med hur det ser ut i lokala jordbruk för att kunna dra slutsatsen att lokalproducerat bidrar till Agenda 2030.

This study aims to complement the internationally implemented method “CEN/TR 15522-2: 2012 WATERBORNE PETROLEUM AND PETROLEUM PRODUCTS - PART 2” (CEN). It is a method for forensic investigations on oil spill identification using gas chromatography coupled with low resolution mass spectrometry in electron ionisation mode (GC-EI-MS), in single ion monitoring mode (SIM). The method uses hydrocarbon fingerprints and biomarker abundances to compare oils from spill sources with oil from suspected sources. This method is implemented by the national forensic centre (NFC) with their main object to perform and develop forensic investigations for successful law enforcement.  The experiment uses four different matrices common within the NFC department: wood ash, soil, fabric and cotton swabs. The method evaluates how different sample preparation and clean-up techniques can extract crude oil and heavy fuel oil without losing important information such as the relative abundance of so-called biomarkers typically looked for in international standard praxis in forensic investigations. In conclusion the implemented CEN method showed a reasonably good extraction from matrixes. Extraction of biomarkers were generally quantitative. Extractions of PAHs worked best in soil and cotton swab matrices. In ash samples, the extraction was not very efficient (between 20-80%). It seems that the PAHs strongly bind to active coal in the ash and cannot be extracted fully. It was also evident that the fabric matrix used was problematic for PAH extraction. The fabric itself seemed to release compounds which interfere with the analysis. In soil samples, 31abR (a biomarker compound) was a reoccurring interference from the matrix. Furthermore, analysis of isoprenoids and alkanes had a very broad analytical variation, seen by that the analytical response for these compounds vary greatly among different samples. SPE-extractions did not work well enough following the protocol in this study to be included as a sample preparation step at the moment. More optimization would be needed before the method could be included as an implemented method.

The information paradox is one of the greatest unsolved mysteries on modern physics that have received major attention since it was first surfaced by Stephen Hawking in the 1970s. The consensus of the information paradox is far from reached and it seems like at least one established law of nature need to go in order to resolve it. The information paradox is in the heart of the conflict between quantum mechanics and general relativity and could be a clue to their unification. In this paper we review problems that comes with the paradox as well as present modern attempts to resolve it. We will look closer on black hole complementarity that tells us that tells us that no observer ever observes a violation of a physical law as well as counter arguments to it, including the firewall paradox. Recently, an entropy inequality was derived that is violated in the framework of Hawking radiation. We will demonstrate that small corrections to the Hawking radiation will not resolve this violation as many believes but make the violation more severe. Finally, we will outline more unconventional attempts to approach the information paradox.

The following article reviews minimal models in conformal field theory (CFT). A two-dimensional CFT has an infinite-dimensional symmetry algebra allowing the theory to be solved exactly with operator product expansions (OPE)s. Minimal models are examples of these that are constructed from unitarity and have a finite number of primary fields. Different minimal models correspond to different twodimensional statistical models as the conformal weights of primary fields correspond to the critical exponents. We will derive the differential equations for the correlation functions of the primary fields which results in constraints on the conformal weights called the fusion rules. The fusion rules arise by requiring the representation to be unitary and they govern which fields will be present in the OPE of two primary fields. The two-dimensional critical Ising model will be considered as an example where the fusion rules are used to obtain the present fields and the OPEs are used to compute the correlators. This allow us to obtain the full dynamics of the system.

This paper concerns the modelling of electricity spot prices in the Nordic-Baltic market. The paper begins with a description of the market and a summary of stylized facts of electricity spot prices. These characteristics are later on used in the calibration of a mean-reverting jump diffusion model. The work ends with simulations of the model and a discussion about further improvements that can be made.