Influence of asperities on fluid and thermal flow in a fracture: a coupled Lattice Boltzmann study

The characteristics of the hydro-thermal flow which occurs when a cold fluid is injected into a hot fractured bedrock depend on the morphology of the fracture. We consider a sharp triangular asperity, invariant in one direction, perturbing an otherwise flat fracture. We investigate its influence on the macroscopic hydraulic transmissivity and heat transfer efficiency, at fixed low Reynolds number. In this study, numerical simulations are done with a coupled lattice Boltzmann method that solves both the complete Navier-Stokes and advection-diffusion equations in three dimensions. The results are compared with those obtained under lubrication approximations which rely on many hypotheses and neglect the three-dimensional (3D) effects. The lubrication results are obtained by analytically solving the Stokes equation and a two-dimensional (integrated over the thickness) advection-diffusion equation. We use a lattice Boltzmann method with a double distribution (for mass and energy transport) on hypercubic and cubic lattices. Beyond some critical slope for the boundaries, the velocity profile is observed to be far from a quadratic profile in the vicinity of the sharp asperity: the fluid within the triangular asperity is quasi-static. We find that taking account of both the 3D effects and the cooling of the rock, are important for the thermal exchange. Neglecting these effects with lubrication approximations results in overestimating the heat exchange efficiency. The evolution of the temperature over time, towards steady state, also shows complex behavior: some sites alternately reheat and cool down several times, making it difficult to forecast the extracted heat.Comment: In Journal of Geophysical Research B (2013) online firs

The Impact of the COVID-19 Pandemic and Russia's Invasion of Ukraine on Electricity Demand: A Case Study of Southern European Countries.

Recent global events, particularly the COVID-19 pandemic and Russia's invasion of Ukraine, have been found to dramatically influence electricity consumption patterns, especially within European nations. In this study, the impacts of these consecutive crises on the electricity demand of selected EU countries: Bulgaria, Greece, Romania, and different regions of Italy were examined. The Ordinary Least Squares regression model was utilized to analyze hourly load data and air temperatures. The findings indicate that the 2020 COVID-19 lockdown reduced consumption uniformly across the studied regions, while the 2022 energy crisis led to varied impacts, with distinct patterns being exhibited in regions within Italy. Remarkably, resilience was shown by Bulgaria during both crises, whereas pronounced effects were experienced in Southern Italy in both periods. The importance of understanding these shifts for effective policymaking and future resilience planning is emphasized in this study. A limitation of the analysis is found in its sole use of aggregate power load data and its generalized modelling. It is suspected that clearer results could be obtained in each case if analyzed the electricity consumption data separated by sectors

CO2 saturation and thickness predictions in the Tubåen Fm., Snøhvit field, from analytical solution and time-lapse seismic data

CO2 migration in a saline aquifer is governed by viscous, capillary and gravitational fluid forces at an early stage of injection, where the dominant flow regime is site specific and controls the fluid migration in the pore space. This study combines the CO2 saturation inverted from time-lapse seismic methods with an analytical expression to define the CO2 flow regime, saturation distribution and layer thickness in the Tubåen Fm. following CO2 injection. Quantitative estimates of the CO2 saturation from time-lapse seismic amplitude versus offset (AVO) and spectral decomposition are compared to a viscous dominated analytical expression of CO2 injection into a saline aquifer. The spatial extent of the CO2 plume obtained from time-lapse spectral decomposition and inverted from time-lapse AVO analysis display good agreement with the analytical expression. The CO2 is limited to an area close to the injection well, with an elongated shape in the channel direction. Comparison between the time-lapse seismic and analytical expression shows that the fluid flow is dominated by viscous forces. CO2 saturation within the plume is constant and close to the residual brine saturation. The influence of gravity is ignorable on the reservoir CO2 flow. CO2 fills the entire sandstone unit up to approximately 50 m away from the injection before the CO2 layer thickness is reduced to a thin wedge that propagates below the overlying shale unit. Reduction in CO2 saturation away from the injection well is a reduction in effective CO2 saturation relative to the thickness of the horizon. The maximum radius of the CO2 layer from the analytic expression is 750 m, of which 400 m is above the time-lapse noise level. Time-lapse seismic analysis reveals the CO2 layer radius is 405 m in the direction of the local fluvial channel and 273 m in the perpendicular direction

Menneskerettighetsundervisning - en innfallsvinkel til empowerment i Peru: En kvalitativ undersøkelse av peruanske læreres forståelse av opplæring "om, for og gjennom" rettigheter.

Denne studien har som mål å gi kunnskap om hvordan menneskerettighetsundervisning kan bidra til empowerment i en sosialt og økonomisk marginalisert befolkning i Peru. Den overordnede problemstillingen for oppgaven er følgende: Hvilken funksjon kan lærerens menneskerettighetsundervisning ha i empowerment-prosesser i en sosialt og økonomisk marginalisert befolkning i Peru? Gjennom en kvalitativ forskningstilnærming, ønsker jeg å rette fokus mot hvordan lærere og andre tilknyttet et veldedig prosjekt i Peru, tilnærmer seg, forstår og praktiserer opplæring «om, for, og gjennom» rettigheter. For å kunne generere data for å svare på oppgavens problemstilling har jeg benyttet meg av et semistrukturert fokusgruppeintervju på Zoom med samtlige lærere i Peru, samt gjennomført et femukers feltarbeid og dermed tilbragt én måned sammen med barna, «tantene», daglig leder og lærerne i Monsefu, Peru. Oppgavens teoretiske rammeverk forankres i en postkolonial tradisjon, der jeg er opptatt av å sette en gruppe ikke-vestlige aktørers verdier, holdninger og meninger i fokus. I tillegg vil Felisa Tibbits sine modeller for menneskerettighetsundervisning være sentrale. Modellene belyser ulike perspektiv på hva menneskerettighetsundervisning kan innebære i forskjellige kontekster og deler av verden, og foreslår pedagogiske og fagdidaktiske tilnærminger som jeg mener er relevante for å belyse sentrale funn i studien. For å forstå bedre begrepet «empowerment» har jeg tatt utgangspunkt i den amerikanske pedagogen Aron Schutz og den canadiske forskeren Catherine Broom sine perspektiver på empowerment og utdanning. Her vil blant annet Freires kritisk pedagogikk samt Deweys tanker om aktiv læring løftes frem og diskuteres. I tillegg til de nevnte forfatterskapene vil også Europarådet og FNs definisjon og utgreiinger om menneskerettighetsundervisning være essensielle. Studien viser at lærerne i Peru anser «respekt» og «solidaritet» som sentrale verdier for mellommenneskelig samhandling i det peruanske samfunnet, og at disse til sammen, utgjør fundamentet for skolens arbeid med rettigheter og empowerment. Gjennom pedagogiske aktiviteter som rollespill, casejobbing og lek, oppfordrer lærerne i Monsefu til aktiv deltakelse, kritisk tenkning og sosialt samspill i klasserommet, og bidrar, gjennom sin elevsentrerte og deltakende undervisning, til å bemyndiggjøre elever som subjekter med rettigheter.This study aims to provide knowledge about how human rights education can contribute to empowerment in a socially and economically marginalized population in Peru. The thesis research question is as follows: What function can the teacher’s human rights education have in empowerment-processes in a socially and economically marginalized population in Peru? Through a qualitative research method, I will focus on how a group of teachers and other workers on a charitable project in Peru, relate to, understand and practice training “about, through and for” human rights. In order to generate data to answer the assessments thesis, I have used a semi-structured focus group interview and completed a five-week fieldwork by spending one month together with the children, aunts, director and teachers in the city of Monsefu, in northern Peru. The theoretical framework of the thesis is rooted in a postcolonial tradition, where I’m concerned with putting the values, attitudes and perspectives of a group of non-western actors in focus. In addition, Felisa Tibbits models for human rights education will also be central. The models shed light on different perspectives on what human rights education can entail in different contexts and parts of the world and suggest pedagogical approaches that I believe are relevant to explain key findings in the study. To understand better the concept of «empowerment» I have taken as my starting point the American educator Aaron Schutz and the Canadian researcher Catherine Broom´s perspectives on empowerment and education. Here, among other things, Freires critical pedagogy as well as Deweys thoughts on active learning will be highlighted and discussed. In addition to the mentioned authorships, the Council of Europe and the UNs definition and deliberations on human rights education will also be essential. The study shows that teachers in Peru consider “respect” and “solidarity” as central values for interpersonal interaction in Peruvian society, and that these together, can form the foundation of empowerment-processes at the school in Monsefu. Through educational activities such as role-play, casework and play, the teachers in Monsefu encourage active participation, critical thinking and social interaction in the classroom, and thus contribute, through their student-centered and participatory teaching, to empower students as subjects of rights

The escape problem for active particles confined to a disc

We study the escape problem for interacting, self-propelled particles confined to a disc, where particles can exit through one open slot on the circumference. Within a minimal 2D Vicsek model, we numerically study the statistics of escape events when the self-propelled particles can be in a flocking state. We show that while an exponential survival probability is characteristic for non-interaction self-propelled particles at all times, the interacting particles have an initial exponential phase crossing over to a sub-exponential late-time behavior. We propose a new phenomenological model based on non-stationary Poisson processes which includes the Allee effect to explain this sub-exponential trend and perform numerical simulations for various noise intensities

Dynamic aerofracture of dense granular packings

International audienceA transition in hydraulically induced granular displacement patterns is studied by means of discrete numerical molecular dynamics simulations. During this transition the patterns change from fractures and fingers to finely dispersed bubbles. The dynamics of the displacement patterns are studied in a rectangular Hele-Shaw cell filled with a dense but permeable two-dimensional granular layer. At one side of the cell the pressure of the compressible interstitial gas is increased. At the opposite side from the inlet of the cell a semipermeable boundary is located. This boundary is only permeable towards the gas phase while preventing grains from leaving the cell. The imposed pressure gradient compacts the grains. In the process we can identify and describe a mechanism that controls the transition of the emerging displacement patterns from fractures and fingers to finely dispersed bubbles as a function of the interstitial gas's properties and the characteristics of the granular phase

Is postmodernism dead? A text on the relevance of postmodern theory in the public sector

Erfaringsbasert master, 90 studiepoeng.Engelsk sammendrag (abstract): This text discusses postmodern organisation theory. Drawing on modern organisational assumptions and the postmodern responses to these assumptions. Including post-bureaucracy and its role on this scene. The purpose of this text is to respond to the question of whether postmodernism is dead, or if the philosophy (still) has relevance for our understanding of organisation as structure and process in public bureaucracies of 2016.Sammendrag: Denne teksten drøfter postmodernistisk organisasjonsteori. Den trekker frem noen moderne antagelser fra organisasjonsteorien og samtidig postmodernismens svar på disse. Den drøfter også postbyråkratiet i forlengelsen av dette. Formålet er å komme nærmere et svar på om postmodernismen er passé, eller om den (fortsatt) har relevans for vår forståelse av organisasjon og organisering av offentlige byråkrati i vår tid av 2016

Læreres oppfatninger av sin relasjon til elever som har assistentstøtte som en del av sitt opplæringstilbud i barneskolen.

Tema for masteroppgaven er lærer- elev relasjon i en kontekst der eleven har assistentstøtte store deler av skoledagen. Formålet med studien var å undersøke læreres erfaringer og refleksjoner rundt dette tema, for på den måten å identifisere faktorer som påvirker relasjonen, hva som kan være utfordrende og hva lærere gjør for å bygge relasjon til elever med assistentstøtte. Dette ga problemstillingen: «Hvilke oppfatninger har lærere av sin relasjon til elever som har assistentstøtte som en del av sitt opplæringstilbud i barneskolen?» Forskningsgrunnlaget er studier om bruk av assistent i skolen, og relasjonens betydning for læring, livsmestring og inkludering. Relasjonsteorien er basert på Piantas relasjonsmodell. Dette er en fenomenologisk inspirert, kvalitativ studie med en hermeneutisk tilnærming, der det er brukt kvalitativt forskningsintervju som metode. Utvalget bestod av seks barneskolelærere, som var kontaktlærere for elever som hadde assistentstøtte gjennom store deler av skoledagen. Gjennom studien kom det fram at betydningen av samarbeid mellom lærer og assistent og tilstrekkelig avsatt tid til dette skilte seg ut som en sentral faktor for lærernes relasjon til elever med assistentstøtte. Et annet hovedfunn var at det er store individuelle forskjeller mellom lærere i forhold til relasjonskompetanse og bevissthet rundt relasjonsbygging generelt og til elever med assistentstøtte spesielt. Det har også vært lite felles fokus på dette i lærernes utdanning og pedagogisk utviklingsarbeid ved skolen. Et tredje hovedfunn var at relasjonens betydning for inkludering og den psykologiske dimensjonen av inkludering kom lite til uttrykk gjennom intervjuene