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Kiruna, Sweden

Riseth J.A.,Sami University College | Tommervik H.,Norwegian Institute for Nature Research | Helander-Renvall E.,University of Lapland | Labba N.,Moskavuona Sami Language and Culture Center | And 9 more authors.
Polar Record | Year: 2011

Scientific studies of challenges of climate change could be improved by including other sources of knowledge, such as traditional ecological knowledge (TEK), in this case relating to the Sámi. This study focuses on local variations in snow and ice conditions, effects of the first durable snow, and long term changes in snow and ice conditions as pre-requisites for understanding potential future changes. Firstly, we characterised snow types and profiles based on Sámi categories and measured their density and hardness. Regression analysis showed that density can explain much of the variation in hardness, while snow depth was not significantly correlated with hardness. Secondly, we found that whether it is dry/cold or warm/wet around the fall of the first durable snow is, according to Sámi reindeer herders, crucial information for forecasting winter grazing conditions, but this has had limited focus within science. Thirdly, elderly herders' observations of changes in snow and ice conditions by 'reading nature' can aid reinterpretation of meteorological data by introducing researchers to alternative perspectives. In conclusion we found remarkable agreement between scientific measurements and Sámi terminology. We also learnt that TEK/science cooperation has much potential for climate change studies, though time and resources are needed to bridge the gap between knowledge systems. In particular, TEK attention to shifts in nature can be a useful guide for science. © Copyright 2010 Cambridge University Press. Source

Krynitz M.,Swedish Space Corporation
Acta Astronautica | Year: 2010

A workshop on the subject was held at SSC Chile in November 2008 at the Santiago Ground Station. Among the 50 participants were twelve space agencies and key individuals from industry. Topics covering frequencies, remote control, communication, LEOP requirements and the future of the commercial market were discussed in separate working groups and reported to the assembly. These findings have been summarised in this paper. One can see a tendency towards Ku-band and in the future Ka-band from X- and S-band. Optical links may be the next logical step. Standardisation processes and de-facto standardised equipment have led to an increase of interoperability between ground stations, but this can be enhanced much further by agreeing on real standards. This affects the preparation phase of the network in a sense that interfaces as well as testing hours are reduced. The result is that prices are dropping in some regions. Overall there is a pressure on all network operators to provide cheaper and faster services without compromising reliability. Agencies are increasingly relying upon commercial sector capacity both for non-routine operations (e.g. LEOPs and backup emergency) and for their daily support needs. Another change is that the commercial sector is consolidating into global networks under private ownership exploiting the synergies that offer one interface and access point. © 2010 Elsevier Ltd. All rights reserved. Source

Nguyen-Thi H.,Aix - Marseille University | Nguyen-Thi H.,CNRS Institute Materials Microelectronics nanosciences of Provence | Reinhart G.,Aix - Marseille University | Reinhart G.,CNRS Institute Materials Microelectronics nanosciences of Provence | And 9 more authors.
Journal of Crystal Growth | Year: 2013

As most of the phenomena involved during the growth of metallic alloys from the melt are dynamic, in situ and time-resolved X-ray imaging should be retained as the method of choice for investigating the solidification front evolution. On Earth, the gravity force is the major source of various disturbing effects (natural convection, buoyancy/sedimentation, and hydrostatic pressure) which can significantly modify or mask certain physical mechanisms. Therefore solidification under microgravity is an efficient way to eliminate such perturbations to provide unique benchmark data for the validation of models and numerical simulations. Up to now, in situ observation during microgravity solidification experiments were limited to the investigations on transparent organic alloys, using optical methods. On the other hand, in situ observation on metallic alloys generally required synchrotron facilities. This paper reports on a novel facility we have designed and developed to investigate directional solidification on metallic alloys in microgravity conditions with in situ X-ray radiography observation. The facility consists of a Bridgman furnace and an X-ray radiography device specifically devoted to the study of Al-based alloys. An unprecedented experiment was recently performed on board a sounding rocket, with a 6 min period of microgravity. Radiographs were successfully recorded during the entire experiment including the melting and solidification phases of the sample, with a Field-of-View of about 5 mm×5 mm, a spatial resolution of about 4 μm and a frequency of 2 frames per second. Some preliminary results are presented on the solidification of the Al-20 wt% Cu sample, which validate the apparatus and confirm the potential of in situ X-ray characterization for the investigation of dynamical phenomena in materials processing, and particularly for the studying of metallic alloys solidification. © 2013 Elsevier B.V. Source

Kemi S.,Swedish Space Corporation
SpaceOps 2012 Conference | Year: 2012

Esrange Space Center located in northern Sweden has during 45 years been a leading launch site for both sounding rockets and stratospheric balloons. We have a unique combination of maintaining both stratospheric balloons and sounding rockets launch operations. Most balloon flights are normally handled inside Scandinavia but since 2005 semi-circular flights are performed with recovery in northern Canada. The Swedish and Russian Governments have signed an agreement for peaceful exploration of space on 9 March 2010, which will permit circumpolar balloon flights. Within this agreement we are able to offer the science community long duration balloon flights in the Northern Hemisphere with durations for several weeks. The balloon operations at Esrange Space Center are yearly expanding. Both NASA and CNES have long term plans for balloon flights from northern Sweden. We have also received requests from Japanese Universities and JAXA for future balloon missions. To handle balloon campaigns with large numbers of payloads or build up for two different campaigns a new big assembly hall was ready for use in April 2011. In total 10 payloads have been flying for 4 to 5 days from Esrange westwards with landing in northern Canada since 2005. The SUNRISE balloon borne solar telescope is one example which made in June 2009 a more than 4 days semi-circular balloon flight from Esrange. The Sunrise project is a collaborative project between the Max Planck Institute for Solar System Research in Katlenburg-Lindau and partners in Germany, Spain and the USA. The first circumpolar flight will take place in the second half of June 2012 with the PoGOLite balloon borne telescope studying the polarisation of gamma-rays from pulsars and will be recovered in Scandinavia after 12-15 days. The PoGoLite project is a collaborative project between Swedish, French, Japanese and US scientific teams. © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Source

Murphy A.G.,University College Dublin | Browne D.J.,University College Dublin | Houltz Y.,Swedish Space Corporation | Mathiesen R.H.,Norwegian University of Science and Technology
IOP Conference Series: Materials Science and Engineering | Year: 2016

In situ X-radiography solidification experiments were performed on Al-based alloys, using both synchrotron and laboratory-based X-ray sources, in conjunction with a gradient furnace and a newly developed isothermal furnace, respectively. The effect of gas porosity nucleation and growth within the semi-solid mush during both columnar and equiaxed solidification was thereby observed. In all experimental cases examined, gas porosity was observed to nucleate and grow within the field-of-view (FOV) causing various levels of distortion to the semi-solid mush, and thereafter disappearing from the sample leaving no permanent voids within the solidified microstructure. During columnar growth, a single bubble caused severe remelting and destruction of primary trunks leading to secondary fragmentation and evidence of blocking of the columnar front. Equiaxed solidification was performed under microgravity-like conditions with restricted grain motion in the FOV. The degree to which the nucleated gas bubbles affected the surrounding grain structure increased with increasing solid fraction. However, bubble sphericity remained unaffected by apparent solid fraction or grain coherency. Source

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