1,720,997 research outputs found
International Conference, Arctic Roads:Operating, maintaining and building roads in a climatically challenging environment
No full textAnnual variations of frost table in Kangerlussuaq Airport, western Greenland
No full textGround-penetrating radar (GPR) has been used to study the annual variations of the frost table beneath the southern parking area at Kangerlussuaq Airport, western Greenland. In autumn 2000, three test areas were painted white in order to reduce further development of depressions in the asphalt pavement initiated by permafrost degradation. One of these white painted areas has been used in the investigations to compare the annual variations of the frost table underneath a normal black asphalt surface to with that below a more reflective surface. The investigations were carried out from July 2005 until August 2006. The GPR measurements have shown a clear correlation between the use of the reflective surface and a reduced depth in the annual variations to the frost table. In late summer (August) the difference in the depths to the frost table is almost 20 ns, which corresponds to approximately 0.9 m. This constitutes a major difference in the thermal conditions below the reflective surface and the normal black asphalt surface
In Situ burning of Arctic marine oil spills:Ignitability of various oil types weathered at different ice conditions. A combined laboratory and field study
Full text linkOil spills in ice filled and Arctic waters pose other challenges for oil spill response compared to open and temperate waters. In situ burning has been proven to be an effective oil spill response method for oil spills in ice filled waters. This thesis presents results from laboratory and field experiments where the ignitability of oil spill as a function of oil type and weathering conditions (time/ice) was tested. The results show that the composition of the oil and the ice cover is important for the in situ burning time-window. The results were used to develop an algorithm that was implemented in a model, so it is possible to predict the operational time-window for in-situ burning
Engineering geological and geophysical investigations for road construction in the municipality of Sisimiut, West Greenland
No full textIn connection with a road construction project between the towns of Sisimiut and Kangerlussuaq in Central West Greenland, the Arctic Technology Centre has been involved in prospecting and site investigations. This paper presents a selection of results concerning the climatic conditions and permafrost distribution, as well as engineering geological and geotechnical investigations conducted. We present data from two soil temperature stations, and show that the recent climatic warming has resulted in changes in the state of the permafrost. Furthermore, we present a geological type section based on engineering geological investigations in the Sisimiut area. Geophysical investigations show that presence of permafrost is widespread, and our results indicate that the vertical thickness of the permafrost may reach 20 m. Further climate warming in the near future will impose high demands on design and construction work in order to counter the effects of permafrost degradation and increased active layer thickness
The New Zealand lichen Pannaria leproloma (Nyl.) P. M. Jørg. and its panaustral relative P. farinosa nom. nov.
No full textPannaria leproloma is shown to be a New Zealand endemic, and is characterized by coarse isidiomorphs/isidia, a high frequency of apothecia and the presence of two cytotoxic scabrosin esters, previously unknown from Pannariaceae, and present in 40 of the samples studied. It is not a member of the Pannaria sphinctrina group, as previously thought. It has frequently been confused with a related, finely sorediate, very sparingly fertile species, which lacks scabrosin esters in more than 99 of the specimens studied. This latter species is widely distributed both in southern South America (where it is one of the most common corticolous lichens), south-eastern areas of Australia and in New Zealand. It was originally described as Psoroma isidiosum, but had to be renamed when transferred to Pannaria, and is here named Pannaria farinosa
Med ild skal olie fordrives
No full textNy forskning viser, hvordan vi effektivt kan bekæmpe olieforurening i Arktis - et område hvor nye olieboringer og sejlruter åbner i takt med, at den smeltende is skaber nye passage
Influence of introduction of e-based distance learning on student experience and performance
Full text linkA new project based course offered by Arctic Technology Centre, Department of Civil Engineering, Technical University of Denmark (DTU) and Department of Bioscience, Aarhus University in collaboration, targets students from the whole circumpolar area. It was developed over a three year period from being taught in class to being taught 100% online. We evaluated the results by analyzing the students’ performance and experience of the course during the three years. The students’ performance increased over the period of transforming the course. Multiple choice quizzes showed to be efficient tools for the students’ selfevaluation, while they did not contribute to their learning. Some contradiction between the group work format of the projects and the online teaching method was experienced by the students. Also student satisfaction decreased slightly - influenced by inconvenient features of the used learning management system, reduced instructor feedback and varying quality of the narration of the lecture videos
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