On the effects of symmetry in the energy balance on a sphere

Simple climate models have gathered much attention as they have suggested the possibility of abrupt climate change associated with tipping points. Several simple climate models are found to have multiple equilibria, but in most cases similar equilibria do not appear or become too difficult to find in complex, fully coupled earth system models. In this thesis, we investigate a simple climate model, an energy balance model on a sphere, and we highlight a possible factor in the behavioral discrepancy between many simple, low-dimensional models and earth system models. A hypothesis is put forward and investigated regarding the effects of symmetry and the presence of multiple equilibria in this simple model. A novel application of boundary integral methods in the context of energy balance models is presented, and used to find semi-analytical solutions to the stationary energy balance equation. The hypothesis is eventually refuted and a new hypothesis is formulated based on the evidence presented: Symmetry violations in energy balance models cause the steady state solutions to become more similar. This is discussed in light of earth system models and how a similar dynamic would make the detection of multiple equilibra challenging in earth system models

Språklege arkaismar i eit utval norske mellomalderballadar

På midten av 1800-talet og fram til kringom hundreårsskiftet vart det samla inn ei mengd folkeviser frå mellom anna Telemark og Setesdal. Folkevisene var munnlege tekster og var uttrykk for ein eldre balladetradisjon som gjekk attende til mellomalderen. Denne oppgåva tek føre seg fire balladar - "Bendik og Årolilja", "Hemingen og Harald kongen", "Roland og Magnus kongen" og "Falkvor Lommansson" - og røkjer etter språkdrag som vitnar om at dei har oppstått i gamalnorsk tid, i tiåra kring 1300.From the middle of the 19th century and until the turn of the century, a large number of traditional songs from, amongst others, the Telemark and Setesdal region, were collected. These traditional songs folk songs were oral texts and were expressions of an older tradition of ballads, going back to medieval times. This paper explores four such ballads - "Bendik og Årolilja", "Hemingen og Harald kongen", "Roland og Magnus kongen" og "Falkvor Lommansson" - and looks for linguistic archaisms which show that these ballads date back to the Old Norse period, to the decades around 1300 CE

On the effects of symmetry in the energy balance on a sphere

Simple climate models have gathered much attention as they have suggested the possibility of abrupt climate change associated with tipping points. Several simple climate models are found to have multiple equilibria, but in most cases similar equilibria do not appear or become too difficult to find in complex, fully coupled earth system models. In this thesis, we investigate a simple climate model, an energy balance model on a sphere, and we highlight a possible factor in the behavioral discrepancy between many simple, low-dimensional models and earth system models. A hypothesis is put forward and investigated regarding the effects of symmetry and the presence of multiple equilibria in this simple model. A novel application of boundary integral methods in the context of energy balance models is presented, and used to find semi-analytical solutions to the stationary energy balance equation. The hypothesis is eventually refuted and a new hypothesis is formulated based on the evidence presented: Symmetry violations in energy balance models cause the steady state solutions to become more similar. This is discussed in light of earth system models and how a similar dynamic would make the detection of multiple equilibra challenging in earth system models

Blødmens funksjon hos Kjartan Fløgstad

Sammendrag Denne oppgaven undersøker de problematiske blødmene i Fløgstads litteratur, og forsøker å forklare de dumme vitsenes funksjon. Påstanden er at blødmene må belyses fra flere perspektiver. Blødmen oppstår som en språklig reaksjon på en situasjon, og må betraktes som en sosial handling. Jeg vil undersøke blødmen ut fra tre perspektiver og begreper; som del av avantgardistisk anti-kunst, som eksempel på situasjonsbasert, språklig motmakt og som den nedvurderte delen av kulturen, det vulgære og tåpelige, som innrømmes en plass i den barokke estetikken. Jeg tar utgangspunkt i Pierre Bourdieus sosiologiske forklaring av litteraturen som et sosialt spill, og belyser Fløgstads posisjon i det litterære feltet innenfor hans handlingsteori. Fløgstads romaner er reaksjoner, negasjoner og manifestasjoner i forhold til de rådende ideene i litteraturen. Alle estetiske og språklige valg skjer innenfor et avgrenset spill. De er bekreftelser eller avvisninger av påstander og sannheter i feltet. Et kunstverk oppstår ikke i det tomme rom. Det er en reaksjon på forutgående verk. Blødmens utpregede tåpelighet og unyttighet er en provokasjon mot det Adorno og Horkheimer omtaler som instrumentell rasjonalitet. Litterært generer den brudd i den estetiske erfaringa. Når Fløgstad tar i bruk disse språklige momentene, plasserer han seg i utkanten av den rådende estetikken. Blødmenes saboterende karakter får preg av å være anti-kunst, i tradisjonen etter den historiske avantgardens angrep på institusjonalisert og autonom kunst. Som avantgarde-strategi kan blødmene forstås som kritikk av det rådende kunstbegrepet. Fløgstad har etablert sitt språksyn innenfor en historisk-dialektisk epistemologi og sosiolingvistisk språkteori. Bakhtins forklaring av språket som essensielt situasjons- og handlingsorientert, forklarer vitsen som et sosialt fenomen. Den er ikke innrettet mot å generere noen dypere form for erkjennelse, eller å framkalle en estetisk erfaring. I enkelte av Fløgstads eksempler fra industrien, i forholdet mellom høy og lav, mellom arbeideren og ingeniøren, blir den dumme vitsen brukt til å endre styrkeforhold og makt i situasjonen. Fløgstad viser til den barokke estetikken, som forsøkte å gestalte en verden som hadde mistet renessansens harmoniske fundament, gjennom å skape disharmoniske og kontrastfylte kunstverk. Paradokset som retorisk figur, sammenstillingen av innbyrdes uforenlige påstander, ble for barokken et emblem på en kaotisk og uoversiktlig verden. Fløgstads påstand er at den relativistiske seinmoderne verden, etter at modernismens og positivismens ideer om absolutt viten har blitt dekonstruert, må framstilles i kunstverk i den barokke tradisjonen

Multifluid modeling of the desulfurization process within a bubbling fluidized bed coal gasifier

The desulfurization process to a two-dimensional (2-D) and three-dimensional (3-D) Eulerian-Eulerian computational fluid dynamic (CFD) model of a coal bubbling fluidized gasifier is introduced. The desulfurization process is important for the reduction of harmful SOx emissions; therefore, the development of a CFD model capable of predicting chemical reactions involving desulfurization is key to the optimization of reactor designs and operating conditions. To model the process, one gaseous phase and five particulate phases are included. Devolatilization, heterogeneous, and homogeneous chemical reactions as well as calcination and desulfurization reactions are incorporated. A calcination-only model and a calcination plus desulfurization model are simulated in 2-D and 3-D and the concentrations of SO2 leaving the reactors are compared. The simulated results are assessed against available published experimental data. The influence of the fluidized bed on the desulfurization is also considered

Effects of limestone calcination on the gasification processes in a BFB coal gasifier

An Eulerian-Eulerian computational fluid dynamics (CFD) model of the gasification processes in a coal bubbling fluidised bed (BFB) is presented incorporating the devolatilisation, heterogeneous, homogeneous reactions and limestone calcination. The model considers separate phases for the coal, limestone and char and is carried out for different experimental conditions taken from the literature.The results of the exiting gas compositions have been averaged over time and validated with experimental data. The hydrodynamic behaviour as well as temperature and reaction distributions within the bed are presented. The impact of limestone calcination on the gaseous composition is observe

The influence of multiple tubes on the tube-to-bed heat transfer in a fluidised bed

There have been few studies modelling both flow and heat transfer in fluidised beds. The kinetic theory of granular flow (KTGF) has been used for flow prediction in the past without heat transfer modelling. In the present study, a two-fluid Eulerian-Eulerian formulation incorporating the KTGF was applied first to a tube-to-bed reactor with one immersed tube and compared with the results in the literature. The bed was then modified to introduce two and three heated tubes. The effects on the flow and temperature distribution, local heat transfer coefficients and averaged heat transfer coefficients over a 3.0s time period were carried out. Results showed that increasing the number of tubes promotes heat transfer from tubes to the particles and flow. The heat transfer coefficients extracted from the single-tube to three-tube cases were analyzed in detail, confirming the importance of linking flow/particle and heat transfer calculation