731 research outputs found
Health and Academic Performance With Happy Children: A Controlled Longitudinal Study Based on the HOPP Project
No full textBACKGROUND: Overweight/obesity in children and adolescents, largely arising due to increased food intake and reduced physical activity, is a major health concern. Physical activity (PA) integrated into learning has been shown to not only lead to improved health outcomes and wellbeing but also positively affect academic performance. The Health and Academic Performance with Happy Children (HAPHC) project aims at enhancing health and academic performance in elementary school children via implementation of a daily unit of Physical Activity Across the Curriculum (PAAC), which is carried out within the school setting. In this project, PA as an integrated part of learning will be evaluated and the learning material adapted for a large scale implementation across several European countries. METHODS: In three European countries (Austria, Slovenia, and Belgium), 12 primary schools in total will be recruited to act as either intervention or control school in a large intervention study, which applies the PAAC pedagogy during lectures. It is estimated that, at least 3,000+ children across the three countries will be recruited in this study. All teachers of intervention schools will receive training and materials/teaching equipment that will allow them to integrate a daily PA unit of 45 min over 3 years across the curriculum. In response to the daily PA intervention, the following primary outcomes will be assessed: changes in health related physiological factors, academic achievement, psycho-social aspects and wellbeing. IMPACT OF PROJECT: The HAPHC project aims at promoting public health by increasing PA at an early age within the school setting and therewith preventing the increasing risk of non-communicable diseases across Europe. HAPHC project aims to develop knowledge and materials, which will ensure that the PAAC can be scalable to other European countries. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov, identifier: NCT04956003
Tang
No full textTang er større planter, der vokser i saltvand. De forskellige slags tang er ikke nødvendigvis nærmere beslægtet. Tang omfatter dels blomsterplanter som ålegræs og dels forskellige slags alger.Langs kysterne ser man ofte volde af opskyllet tang. Det meste opskyl er ålegræs, blæretang eller savtang. Roder man lidt i bunkerne, dukker mange andre arter frem i en mangfoldighed af former og farver, der kan være værd at undersøge nærmere.Hvis man vil kigge nærmere på diversiteten, når man ret langt ved bare at rode i bunken, men med en indslagslup med 10 x forstørrelse og en flad, hvid sorteringsbakke eller balje, får man pludselig mange flere arter med.Hæftet her er et redskab til at bestemme tang i danske farvande. Det er beregnet til brug for almindelige strandgængere og naturinteresserede. Omtale af de forskellige blomsterplanter i havet findes på side 38. De øvrige tangplanter er makroalger og tilhører tre store og i øvrigt ikke beslægtede grupper af alger nemlig grøn-, brun- og rødalger.Langt de fleste af de almindelige, større alger findes i hæftet og kan bestemmes til slægt men ikke altid til art. Små, sjældne, nærtstående og vanskelige arter er ikke med. Vi har ønsket udelukkende at bruge makroskopiske karakterer til bestemmelse. Det vil sige, hvad man kan se i felten med det blotte øje og evt. en håndholdt lup
Experimental investigation of sulfur compound elimination from corrosion inhibitors
No full textCorrosion poses significant economic, safety, and environmental challenges in the oil and gas industry, necessitating effective corrosion inhibition strategies. Chemical inhibitors offer a cost-effective solution, yet selecting the appropriate formulation remains complex due to diverse field compositions and metallurgies. Film-forming inhibitors such as phosphate esters, imidazolines, and quaternary ammonium compounds along with sulfur compounds are widely used to combat CO2 and H2S corrosion. However, the environmental and health impacts of using sulfur compounds warrant investigation into alternative formulations.
This study aims to assess the synergistic effect of H2S in the absence of sulfur compounds on C1018 carbon steel corrosion. The corrosion behavior of C1018 carbon steel in 3% NaCl brine with either pure CO2 or CO2/H2S was evaluated using the static bubble test and dynamic rotating cage autoclave experiment at 60 °C and 20 °C to investigate the synergistic effect of H2S on carbon steel pipes. The influence of pH, temperature, and H2S concentration on corrosion inhibitor performance was reviewed. Results indicate that phosphate esters, imidazoline, and quaternary amines exhibit higher inhibition efficiency in CO2/H2S environments without sulfur compounds. Notably, even at lower H2S concentrations, imidazolines, and quaternary amines demonstrate stable inhibitory rates. In a field case study, the corrosion rate of an imidazoline corrosion inhibitor was measured. When exposed to 0.035% H2S, the average corrosion rate was determined to be 0.0365 mm/y. This rate was lower than the corrosion rate observed when both a sulfur compound and 0.035% H2S were present, which was 0.08 mm/y. Eliminating sulfur compounds from corrosion inhibitor formulations offers environmental benefits and mitigates health risks. The findings underscore the importance of understanding chemistry and complex chemical interactions in corrosion environments and should be investigated further to optimize the inhibitor formulations for enhanced performance and reduced environmental impact
Experimental and theoretical studies of rapid phase transitions in CO2
No full textRapid depressurization and evaporation of a pressurized liquefied gas are phenomena of relevance to hazard identification and risk analysis in the process industry. Tank explosions and pipeline ruptures are accident scenarios that happen infrequently but have the potential to cause fatalities and significant material damage. This thesis presents results from small-scale experiments and calculations on the rapid depressurization and evaporation of pressurized liquefied carbon dioxide (CO2) in vertical ducts. A motivation was to quantify the damage potential of a sudden CO2 release that originates from scenarios such as a boiling liquid expanding vapor explosion (BLEVE). The primary aim was to describe characteristic velocities and properties behind the evaporation wave as a function of the thermodynamic states ahead of the wave.
The experimental setups in the study included a transparent polycarbonate tube and a rectangular duct. The test sections were filled with pressurized CO2 and sealed with a diaphragm at the upper end. A pulse generator initiated the tests and triggered the diaphragm puncture-device. The instrumentation included pressure sensors, temperature sensors, and high-speed cameras. Upon diaphragm rupture, a rarefaction wave propagated at the local speed of sound into the vapor headspace and further into the liquid phase. Wave reflections occurred at the liquid-vapor interphase and the bottom surface. An evaporation wave followed behind the rarefaction wave. The calculated evaporation wave velocities were in the range 32-42 ms-1. Heterogeneous nucleation occurred at the wall surface ahead of the evaporation wave. Neither the transparent polycarbonate tube nor the square-duct glass-window setup provided a sufficiently smooth surface to suppress nucleation and bubble growth at the surface. The evaporation front details were obscured by the vapor bubbles at the glass window. One test campaign focused on the blast from the CO2 released into an openly vented atmospheric chamber. The measured peak overpressure was in the range 15 – 20 kPa. The initial pre-rupture state was saturated CO2 at room temperature (272 ± 1 K). The rapid boiling did not contribute to the initial shock strength in the test geometry. The evaporation rate was too slow, and the velocity behind the evaporation wave seemed too low to create a shock wave. The heterogeneous wall nucleation seemed to limit the degree of superheat. The tests with a liquid/vapor mixture in the high-pressure reservoir showed a significantly higher impulse compared to the vapor-only tests. Reducing the vent area from 0.1 m2 to 0.01 m2 resulted in a slight increase in the impulse calculated at time t = 100 ms after diaphragm rupture. The experimental results provided reference data that can be used to develop interfacial flux source terms applied in phase transition models. A Rankine-Hugoniot analysis that modeled the phase transition as an evaporation wave calculated the fluid properties behind a CJ wave. Velocities and pressures calculated by model showed good qualitative agreement with the experimental results that were sampled from three separate test setups. The required model inputs were the initial pre-rupture pressure and the pressure of the metastable liquid ahead of the evaporation wave. Typically, the calculated vapor mass fraction behind the evaporation wave was in the range from 0.21 to 0.23. The somewhat limited vapor mass fraction could explain why the rapid evaporation investigations did not produce an observable shock wave. The thesis describe a strategy, which includes the calculated vapor fraction, to predict the mechanical energy released in the rapid depressurization and evaporation processes.publishedVersio
Simulation of ammonia cracker process with Aspen HYSYS
No full textAmmonia is recognized as a promising marine fuel due to its potential to reduce emissions especially CO2, serving both as an energy carrier and a clean fuel. In 2018, the International Maritime Organization (IMO) set targets to reduce greenhouse gas emissions from international shipping by at least 50% by 2050, aiming for complete elimination by 2100.
This MSc thesis is a continuation of the work done in the MSc group project (at USN, autumn 2023). New contributions include addressing the weaknesses identified in that project by reducing some of the proposal simplifying assumptions.
In this study, a centralized ammonia cracking process is simulated using Aspen HYSYS V12 with available data from the literature. In the simulation phase, a base case was established, then four other cases were simulated to maximize energy recovery from the waste heat of the cracker product. The improvement evolved through different versions of the improved case, culminating in the final version. For the base case with no heat recovery, the produced H2/NH3 total feed on a kg/kg basis was evaluated as 0.1282 while for the final version of the improved case, it was calculated to be 0.1404.
To determine the most efficient case, the Levelized Cost of Hydrogen (LCOH) was evaluated and compared. The final version of the improved case, with the highest hydrogen production rate (585.8 kgmoles/h hydrogen from 500 kgmoles/h total ammonia feed) and the lowest LCOH (less than 6 USD/kg H2), was deemed the most efficient.
Recommendations for further work include tackling inherent uncertainties in the simulation like inclusion of catalyst data, defining furnace instead of Gibbs reactor, and using data from the adsorption module of Aspen to precisely model the adsorption phenomena and conducting uncertainty analysis on the LCOH evaluations to obtain more reliable techno-economic analysis
BA 2013: The Academy of Fine Art
No full textStudenter: Kristoffer Anders Skogheim Amundsen, Bjarne Bare, Jørn Bjercke, Sindre Brusselmans, Tobias Alexander Danielsson, Miriam Hansen, Siri Iversen-Ejve, Henrik Mojord Jahnsen, Silje Johannessen, Linda Karin Larsen, Solveig Lønseth, Svetlana Negashova, Sara Jenny Charlotta Rönnbäck, Lise Steingrim, Peter Christian Sæbø, Morten Jensen Vågen, Per Joel Sebastian Westerlund og Ruben Aas. - Kurator og redaktør: Natalie Hope O’Donnell. - ISBN 978-82-92613-44-
Samlede anmeldelser
No full textIndhold:
Erik Hansen, professor, dr.phil., Københavns Universitet: Holberg-Ordbog. Ordbog over Ludvig Holbergs Sprog. Redigeret af Aage Hansen, fra 1957 sammen med Sv. Eegholm-Pedersen, under medvirken af Christopher Maaløe. Det danske Sprog- og Litteraturselskab. Reitzel 1981
Svend Bruhns, bibliotekar, Det nordjyske Landsbibliotek, Aalborg: Erik Hansen og Nana Riemann: Bibliografi over moderne dansk rigssprog 1850-1978. Gjellerup 1979
Frans Gregersen, universitetslektor, cand.mag., Københavns Universitet: Bo Jacobsen: De højere uddannelser mellem teknologi og humanisme. En uddannelsessociologisk analyse. Bibliotek Rhodos, København 1981
Torben Kisbye, universitetslektor, cand.mag., Århus Universitet: Hans Frede Nielsen: De germanske sprog - baggrund og gruppering. Odense Universitetsforlag 1979
Arne Hamburger, amanuensis, cand.jur., Dansk Sprognævn: Erik Hansen: Skrift, stavning og retstavning. Hans Reitzel 1981
Flemming Lundgreen-Nielsen, universitetslektor, dr.phil., Københavns Universitet: Petter Dass: Samlede verker I-III ved Kjell Heggelund, Sverre Inge Apenes og Karl Erik Harr. Gyldendal Norsk Forlag. Oslo 1980
Niels Kofoed, studielektor, dr.phil., Københavns Dag- og Aftenseminarium: Johan de Mylius: Myte og Roman. H.C. Andersens romaner mellem romantik og realisme. En traditionshistorisk undersøgelse. Gyldendal 1981
Flemming Lundgreen-Nielsen, universitetslektor, dr.phil., Københavns Universitet: Keld Zeruneith: Den frigjorte. Emil Aarestrup i digtning og samtid. En biografi. Gyldendal 1981
Per Dahl, mag.art., Aarhus Universitet: Sven Møller Kristensen: Georg Brandes. Kritikeren, liberalisten, humanisten. Gyldendal 1980
Per Dahl, mag.art., Aarhus Universitet: Georg Brandes og Emil Petersen. En Brevveksling udgivet af Morten Borup. Lademanns forlag 1980
Finn Brandt-Pedersen, studielektor, Kolding Seminarium: Erik Skyum-Nielsen: Ideologi og æstetik i H.C. Branners sene forfatterskab. Udgivet med støtte af Statens humanistiske Forskningsråd. Gyldendal 1980
Erik Skyum-Nielsen, seniorstipendiat, mag.art., Københavns Universitet. Lise Loesch: Tamme fugle længes - vilde flyver. Avantgardelyrik i Danmark, Finland og Sverige i mellemkrigstiden. Akademisk Forlag 1980
Mogens Baumann Larsen, professor, cand.mag., Aalborg Universitetscenter. Arne Espegaard: Liv og sprog på svundne tiders Læsø. En tekst- og opslagsbog om dagligliv og dagligsprog i et fiskermiljø. 2 bind. Fiskeri- og Søfartsmuseet. Esbjerg, 1978
Klaus Kjøller, lektor, cand.mag., Københavns Universitet. Svar på Ulf Telemans anmeldelse af »Mod en argumentationsteori« i Danske Studier 198
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