Tunable superconducting critical temperature in ballistic hybrid structures with strong spin-orbit coupling

We present a theoretical description and numerical simulations of the superconducting transition in hybrid structures including strong spin-orbit interactions. The spin-orbit coupling is taken to be of Rashba type for concreteness, and we allow for an arbitrary magnitude of the spin-orbit strength as well as an arbitrary thickness of the spin-orbit coupled layer. This allows us to make contact with the experimentally relevant case of enhanced interfacial spin-orbit coupling via atomically thin heavy metal layers. We consider both interfacial spin-orbit coupling induced by inversion asymmetry in an S/F-junction, as well as in-plane spin-orbit coupling in the ferromagnetic region of an S/F/S- and an S/F-structure. Both the pair amplitudes, local density of states and critical temperature show dependency on the Rashba strength and, importantly, the orientation of the exchange field. In general, spin-orbit coupling increases the critical temperature of a proximity system where a magnetic field is present, and enhances the superconducting gap in the density of states. We perform a theoretical derivation which explains these results by the appearance of long-ranged singlet correlations. Our results suggest that $T_c$ in ballistic spin-orbit coupled superconducting structures may be tuned by using only a single ferromagnetic layer.Comment: 14 pages, 14 figures. Published in PR

Verdsettelse av Fred Olsen Energy

Denne masterutredningen tar for seg en verdivurdering av Fred Olsen Energi (FOE). For å utføre verdsettelsen har vi hovedsakelig benyttet en fundamental verdsettelse som er foretatt ut fra perspektivet til en veldiversifisert investor. For å opparbeide oss et godt utgangspunkt for å utføre den fundamentale verdsettelsen har vi foretatt strategisk analyse, markedsanalyse og regnskapsanalyse. Kunnskapene vi har tilegnet oss i disse analysene har vi brukt for å estimere framtidsprognoser. Framtidsprognosene er sammen med estimering av avkastningskravet grunnlaget for den fundamentale verdsettelsen. Modellen vi har brukt i den fundamentale verdsettelsen er en nåverdiberegning av fri kontantstrøm til totalkapitalen. Videre har vi anvendt sensitivitetsanalyser og ”peer review” for å vurdere risikoen og rimeligheten for verdiestimatet fra den fundamentale verdsettelsen. Til slutt konkluderer vi med en kjøpsanbefalning basert på vår verdivurdering av selskapets aksjer

Magnon-polarons in cubic collinear Antiferromagnets

We present a theoretical study of excitations formed by hybridization between magnons and phonons - magnon-polarons - in antiferromagnets. We first outline a general approach to determining which magnon and phonon modes can and cannot hybridize in a system thereby addressing the qualitative questions concerning magnon-polaron formation. As a specific and experimentally relevant case, we study Nickel Oxide quantitatively and find perfect agreement with the qualitative analysis, thereby highlighting the strength of the former. We find that there are two distinct features of antiferromagnetic magnon-polarons which differ from the ferromagnetic ones. First, hybridization between magnons and the longitudinal phonon modes is expected in many cubic antiferromagnetic structures. Second, we find that the very existence of certain hybridizations can be controlled via an external magnetic field, an effect which comes in addition to the ability to move the magnon modes relative to the phonons modes.Comment: arXiv admin note: text overlap with arXiv:1808.0901

Influence of grain-refiner addition on the morphology of fe-bearing intermetallics in a semi-solid processed Al-Mg-Si alloy

© The Minerals, Metals & Materials Society and ASM International 2013The three-dimensional morphologies of the Fe-bearing intermetallics in a semisolid-processed Al-Mg-Si alloy were examined after extracting the intermetallics. α -AlFeSi and β-AlFeSi are the major Fe-bearing intermetallics. Addition of Al-Ti-B grain refiner typically promotes β-AlFeSi formation. β-AlFeSi was observed with a flat, plate-like morphology with angular edges in the alloy with and without grain refiner, whereas α -AlFeSi was observed as "flower"-like morphology in the alloy with grain refiner. © 2013 The Minerals, Metals & Materials Society and ASM International

Effect of Phosphorus and Strontium Additions on Formation Temperature and Nucleation Density of Primary Silicon in Al-19 Wt Pct Si Alloy and Their Effect on Eutectic Temperature

The influence of P and Sr additions on the formation temperature and nucleation density of primary silicon in Al-19 wt pct Si alloy has been determined, for small volumes of melt solidified at cooling rates _T of ~0.3 and 1 K/s. The proportion of ingot featuring primary silicon decreased progressively with increased Sr addition, which also markedly reduced the temperature for first formation of primary silicon and the number of primary silicon particles per unit volume �Nv: When combined with previously published results, the effects of amount of P addition and cooling rate on �Nv are in reasonable accord with �Nv� _T ¼ ðp=6fÞ1=2 109 [250 � 215 (wt pct P)0.17]�3, where �Nv is in mm�3, _T is in K/s, and f is volume fraction of primary silicon. Increased P addition reduces the eutectic temperature, while increased Sr appears to generate a minimum in eutectic temperature at about 100 ppmw Sr

Reconstruction of a genome-scale metabolic model for the analysis of the leaginous phenotype of Aurantiochytrium sp. T66

Thraustochytrider er heterotrofe protister som under bestemte betingelser akkumulerer store mengder triglyserider som er svært rike på omega-3-flerumettede fettsyrer. Det økende globale behovet for disse fettsyrene har gjort thraustochytrider til særlig lovende kandidater for mikrobiell produksjon av disse. En forståelse på systemnivå av den metabolske overgangen fra eksponentiell vekst til lipidakkumulering er derimot fortsatt uklar. Genome-skala metabolske modeller (GSM) muligjør en forståelse på systemnivå av organiseringen og adferden til biokjemiske nettverk. Denne modelleringsmetoden integrerer samtlige metabolske egenskaper til organismen ved bruk av et såkalt støkiometrisk rammeverk som muliggjør den simultane beregningen av samtlige reaksjonshastigheter i hele det metabolske nettverket. Disse cellulære fenotypene bidrar til stor innsikt i egenskapene til det metabolske systemet, og har av nettopp denne grunnen blitt til et av de viktigste verktøyene innen systembiologisk forskning på metabolske systemer. GSM inkorporerer også direkte forbindelser mellom genotyper og biokjemiske fenotyper ved bruk av boolske gen-reaksjon-assosiasjoner, som muliggjør direkte simulering av knockout-strategier for økt målmetabolittproduksjon. Ved bruk av en allerede publisert GSM av en nært beslektet stamme, ble en GSM av høy kvalitet rekonstruert for thraustochytriden Auranthiochytrium sp. T66. Ved hjelp av iterative modifikasjoner og forbedringer ble det metabolske omfanget og dekningsgraden til modellen utbedret sammenlignet med templatmodellen. Den endelige modellen inneholdt 2093 unike metabolske reaksjoner, 1668 metabolitter, og 1191 tilhørende gener. Simulerte genessensialitetsanalyser på minimalt karbon-medium antydet at det metabolske nettverket er både robust og tilpasningsdyktig, ved å oppnå optimal eller sub-optimal vekst for rundt 81\% av alle gen-knockouter. Flere doble reaksjonsmutanter ble identifisert ved bruk av OptKnock-algoritmen som resulterte i økte produksjonsrater av de essensielle lipid-forløperne malonyl-CoA og NADPH. Ved inkorporering av transkriptomdata ble det også oppdaget en sammenfallende nedregulering av spesifikke reaksjonsspor i aminosyremetabolismen ved nitrogen-begrensing, noe som tyder på en konservert reguleringsmekanisme som også er observert i andre oljeholdige mikroorganismer. Den sistnevnte analysen antyder også en bimodal reguleringsmekanisme der fettsyrasyntase-komplekset (FAS) virker å være primært regulert på transkriptomnivå, mens det konkurrerende enzymkomplekset ansvarlig for produksjnoen av de omega-3-flerumettede fettsyrene, polyketid-syntase (PKS), tilsynelatende er regulert på metabolittnivå. Dette kan tyde på at en økning av den intracellulære mengden av lipid-forløperne vil kunne øke aktiviteten til PKS, og i mindre grad påvirke aktiviteten til FAS, som følgelig vil kunne forbedre den fraksjonelle sammensetningen av de ønskede omega-3-fettsyrene i A. sp. T66.Thraustochytrids are heterotrophic protists that under certain conditions accumulate large quantities of triacylglycerols (TAGs) rich in omega-3 polyunsaturated fatty acids (PUFAs). The increasing global demand for these PUFA-rich TAGs has consequently made the thraustochytrids being regarded as primary candidates for microbial lipid producing cell factories. However, a systems-level understanding of the metabolic shift from exponential growth to lipid accumulation is in a large extent unclear. Genome-scale metabolic models (GSMs) allow for a systems-level understanding of the organization and behavior of biochemical networks. The modeling approach integrates all the metabolic capabilities of an organisms within a stoichiometric framework, enabling the in silico prediction of the reaction fluxes throughout the metabolic network. The ability to predict cellular phenotypes offers major insights into the properties of metabolic systems, and constraint-based analyses have, for this reason, become one of the most important tools in the systems biological studies of metabolism. GSMs also provide direct correlations between the genotype and biochemical phenotype through boolean gene-reaction associations, allowing for the direct simulation of metabolic engineering strategies. Using an already published GSM of a closely related strain, a high-quality GSM of the thraustochytrid Auranthiochytrium sp. T66 termed iVS1191 was reconstructed. Through iterative refinements and extensive manual curation, the metabolic scope and coverage of the model was significantly improved from that of the template reconstruction. The generated model consisted of 2093 unique metabolic reactions, 1668 metabolites, and 1191 associated genes. Simulated gene essentiality predictions on carbon-limited minimal medium revealed a robust and adaptable metabolic network, able to grow at sub-optimal or optimal growth phenotypes for around 81\% of all single-gene knockouts. Using the OptKnock algorithm, multiple double-reaction knockout strategies were proposed for the increased production the key lipid precursors malonyl-CoA and NADPH. Additionally, the integration of genome-wide transcriptomics data indicate a concurrent down-regulation of specific pathways of the amino acid metabolism at the onset of lipid accumulation, alluding to a conserved transcriptional regulation also observed in other oleaginous microorganisms. The latter analysis also suggest a bimodal regulatory mechanism by which the fatty acid synthase (FAS) complex appears to primarily be regulated on the transcriptional level, while the competing polyketide synthase (PKS) pathway, responsible for the biosynthesis of the omega-3 PUFAs, seems to be regulated on the metabolic level. These results suggest that increasing the intracellular pool of lipid precursor might preferentially benefit the flux through the PKS pathway compared the FAS system, thus increasing the fractional amounts of the omega-3 PUFA in A. sp. T66

Vortex Induced Vibrations of Slender Catenary Structures

A wide range of offshore science and engineering applications utilize slender catenary-shaped structural elements in their design. These applications include moorings and steel catenary riser designs. The susceptibility of these slender catenary-shapes to vortex-induced vibrations remains the subject of theoretical, numerical and experimental studies. This thesis studies the measured responses from the 2001 MARINTEK experiment with the purpose of trying to understand the relation between analytical models, numerical models, and experimental measurements. The time domain decomposition (TDD) method is implemented in a Matlab program, considering three velocity cases of cross-flow displacements in the catenary plane. The results show that in each of the cases, one of the frequencies has a higher degree of contribution than other frequencies. However, multiple frequencies are present throughout the measurements. Also, the frequencies corresponding to each mode varies. According to the MAC-criterion, the obtained mode shapes have a high degree of correlation with the numerically calculated mode shapes. For verification of the TDD results, the poly-reference least squares complex frequency method and the data- and covariance-driven stochastic subspace methods of operational modal analysis (OMA) are used for studying the data in the commercial Matlab toolbox MACEC. As for the TDD method, the mode shape estimates have high MAC-values, and the corresponding natural frequencies vary. The damping estimates show a great amount of scatter. Also, there is a varying degree of certainty in the results according to result processing guidelines. The effect of accelerometer masses and first order added mass effects are studied using a numerical model in Matlab. The effects of the masses are concluded to be negligible. A comparison between the operational modal OMA obtained eigenfrequencies and the corresponding numerically calculated modes show a great amount of agreement in how the natural frequencies increase with mode number. However, for this case study, the analytical and numerical calculations appear to underestimate magnitudes of the frequencies. Also, there is an indication that the frequencies corresponding to each mode shape vary, possibly resulting from higher order added mass effects

Proximity effect in ballistic superconductor-ferromagnet structures with spin-orbit coupling

The Bogoliubov-de Gennes equations have been solved numerically for a number of two-dimensional ballistic proximity structures comprised of superconductors, normal metals and ferromagnets, with both interfacial and in-plane spin-orbit coupling. These results have been compared to results obtained for similar structures in the absence of spin-orbit coupling. The results show that spin-orbit coupling in general enhances superconductivity in ferromagnet-superconductor-structures, and causes the critical temperature, as well as singlet and triplet amplitudes, to become dependent upon the orientation of the magnetic field. The protective effect of spin-orbit coupling on the superconducting state grows stronger the closer the magnetic field comes to being perpendicular to the effective fields induced by spin-orbit coupling. Both interfacial and in-plane spin-orbit coupling have these effects in common, but the effect is most prominent for the in-plane spin-orbit coupling. The observed effects can be explained by projecting the Cooper pair states onto the eigenbasis of the system, which reveals that the singlet state adapts a long-ranged pseudotriplet component in the presence of spin-orbit coupling. Spin-orbit coupling thus serves as an alternative to inhomogeneously magnetized structures, as it enables control of the critical temperature, as well as both singlet and triplet amplitudes, by adjusting macroscopic parameters. Additionally, the protective effect spin-orbit coupling introduces on the superconducting state allows for such structures to be made smaller than in its absence

A Computational Tool for Simulation and Modeling of Integrated Petroleum Production Systems

Gjennom masterarbeidet har et beregningsverktøy for simulering og modellering av integrerte petroleumsproduksjonssystemer blitt utviklet. Beregningsverktøyet er tilgjengeliggjort som en webapplikasjon. Webapplikasjonen har blitt utviklet i Python ved bruk av Streamlit-biblioteket. Applikasjonen er en plattform hvor ulike simulering og modelleringsoppgaver knyttet til integrerte petroleumsproduksjonssystemer kan kjøres i modulære beregningsrutiner. Målet med applikasjonen er å tilby automatiserte beregningsprosedyrer som effektiviserer beregningsprosesser som ellers typisk gjøres i Microsoft Excel. Applikasjonen har even til å hente offentlige data om petroleumsaktiviteter på norsk kontinentalsokkel med et klikk. Dataen er tilgjengliggjort av Sokkel Direktoratet (Sodir). Dette muliggjør enkel henting av daglig oppdaterte petroleum data, som videre kan brukes til visualisering, modellering og simuleringsformål i applikasjonen. Per juni 2024 består applikasjonen av fire moduler med bruksområder innen feltutvikling, tids- og kostnadsplanlegging, reservoartrykksimulering og dataanalyse for felt på norsk sokkel. Applikasjonens mest utviklede modul ligger innenfor feltutvikling. Feltutviklingsmodulen tilbyr beregningsrutiner for å simulere produksjonsprofiler, analysere NPV, optimalisere feltvariabler og kvantifisere hvordan usikkerhet i variabler påvirker NPV-en til et prosjekt. Applikasjonens andre modul muligjør Monte Carlo-simuleringer for å estimere aggregerte sannsynlighetsfordelinger. Modulen har flere bruksområder, men er hovedsakelig relevant innen kostnads- og tidsplanlegging der flere uavhengige komponenter utgjør en enhet eller operasjon. I applikasjonens tredje modul kan brukere simulere hvordan et reservoartrykk utvikler seg ved produksjon av gass. Brukeren kan laste opp produksjonsdata til applikasjonen eller bruke produksjonsdata for felt på Norsk sokkel hentet fra Sodir. Applikasjonens fjerde modul kan brukes til å visualisere produserte volumer og vannkutt fra felt på norsk sokkel. Modulen kan også brukes til å analysere utviklingen i produksjonsdata ved lineær regresjon, som kan ha nytte for å forutsi produksjonutviklingen og fremtidige produksjonsvolumer. Videre kan modulen visualisere utstrekningen av et felts reservoar(er) sammen med posisjonene og informasjon om produserende, injiserende, stengte og pluggete \& forlatte brønner på norsk sokkel. Link til web-applikasjonen: https://smipps.streamlit.app/ Link til GitHub repository: https://github.com/mortevs/Master-Project (Web-applikasjonen burde kjøres med Google Chrome som nettleser)The master project involves the development of a computational tool for the simulation and modeling of integrated petroleum production systems. An open-source, Python-based web application has been developed for this purpose. The application has been developed using the Streamlit library. The application serves as a platform for conducting a variety of investigations, modeling, and simulation tasks, carried out through the execution of modularized computational routines. The application seeks to streamline computational processes compared to conducting these analyses in Excel. Daily updated public data on the petroleum activities on the Norwegian Continental Shelf can seamlessly be fetched, and utilized for various purposes in the application. As of June 2024, the application consists of four modules, with areas of use within field development, time and cost planning, reservoir pressure simulation, and data analysis for fields on the Norwegian Continental Shelf (NCS). The application's most developed module lies within the scope of field development. The field development module allows for simulating production profiles, NPV analysis, field-variable optimization, and quantification of variable uncertainty on the NPV. The application's second module offers functionality to perform Monte Carlo simulations to analyze aggregated probability distributions. The module has several areas of use, but predominantly in the domain of cost and time planning where several independent components make up an equipment or operation. The third module of the application allows for reservoir pressure simulation following the extraction of gas. The user can upload production data to the application for analyses, or use publicly available production data for an NCS field. The application's fourth module can display produced volumes and water cuts for fields on the NCS. It can also curve fit production data to extrapolate trends into the future to forecast production volumes and water cuts. Furthermore, the module can display the areal extension of the reservoir(s) together with the position and information on producing, injecting, closed, and plugged \& abandoned wells for an NCS field. Link to the web-application: https://smipps.streamlit.app/ Link to the GitHub repository: https://github.com/mortevs/Master-Project (The application should be run using Google Chrome as the web browser

Development of Gold Auranofin Analogues against Multidrug Resistant Bacteria Including Neisseria Gonorrhoeae

Denne oppgaven vil presentere en gjennomgang av nyere forskning på medikamentet Auranofin,som ble godkjent av det amerikanske legemiddelverket (FDA) som et antiaritmetisk legemiddel. Auranofin er ett gull basert medikament som har er fordi det har vist seg å være effektivt i behandlig av flere multi-legemiddelresistente (MDR) Gram-positive bakterier, inkludert Meticillin-resistente \textit{Staphylococcus aureus} (MRSA). MRSA er årlig grunn i over halvparten av alle dødsfall på grunn av multiresistente (MDR) bakterier i USA. Auranofin mangler aktivitet mot de fleste Gram negative bakterier, men det har vist seg at det er effektiv mot \textit{Neisseria gonorrhoeae} (NG). NG er baktereien som gir den seksuelt overførbare sykdommen gonoré. NG har vært utsatt for utvikling av resistens mot antibiotika, og det er et et prekært behov for nye nye behandlinger av sykdommen. I tillegg vil det blir sett næreme på forsjellige analoger av Auranofin, som er både mer aktive mot Gram negative bakterier, dreper bakterer bedre, og har lavere cytotoksisitet.This thesis will present a review of recent literature on Auranofin, a United States Food and Drug Administration (FDA) approved gold based anti arthritic drug. Auranofin drug might be of interest for repurposing as an antibacterial agent. This is as it has been proven to have potent inhibition of multiple multi drug-resistant (MDR) gram positive bacteria, including Methicillin-resistant \textit{Staphylococcus aureus} (MRSA). MRSA is the reason is the reason for half of all deaths from multidrug resistance (MDR) bacteria in the United States. Auranofin lacks activity against most Gram negative bacteria, but has been found to be effective against \textit{Neisseria gonorrhoeae} (NG). NG is the causes of the sexually transmitted disease (STD) gonorrhea. NG has been prone to development of resistance against many classes of antibiotics, and there is an urgent need for new novel treatments of the disease. In addition, recent research on analogues of Auranofin, that are more active towards Gram negative bacteria, and also lowering the cytotoxity will be presented