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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Arvidson, R. E., et al.
(författare)
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Opportunity Mars Rover mission : Overview and selected results from Purgatory ripple to traverses to Endeavour crater
- 2011
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Ingår i: Journal of Geophysical Research. - Hoboken : Wiley-Blackwell. - 0148-0227 .- 2156-2202. ; 116, s. E00F15-
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Tidskriftsartikel (refereegranskat)abstract
- Opportunity has been traversing the Meridiani plains since 25 January 2004 (sol 1), acquiring numerous observations of the atmosphere, soils, and rocks. This paper provides an overview of key discoveries between sols 511 and 2300, complementing earlier papers covering results from the initial phases of the mission. Key new results include (1) atmospheric argon measurements that demonstrate the importance of atmospheric transport to and from the winter carbon dioxide polar ice caps; (2) observations showing that aeolian ripples covering the plains were generated by easterly winds during an epoch with enhanced Hadley cell circulation; (3) the discovery and characterization of cobbles and boulders that include iron and stony-iron meteorites and Martian impact ejecta; (4) measurements of wall rock strata within Erebus and Victoria craters that provide compelling evidence of formation by aeolian sand deposition, with local reworking within ephemeral lakes; (5) determination that the stratigraphy exposed in the walls of Victoria and Endurance craters show an enrichment of chlorine and depletion of magnesium and sulfur with increasing depth. This result implies that regional-scale aqueous alteration took place before formation of these craters. Most recently, Opportunity has been traversing toward the ancient Endeavour crater. Orbital data show that clay minerals are exposed on its rim. Hydrated sulfate minerals are exposed in plains rocks adjacent to the rim, unlike the surfaces of plains outcrops observed thus far by Opportunity. With continued mechanical health, Opportunity will reach terrains on and around Endeavour's rim that will be markedly different from anything examined to date. Copyright 2011 by the American Geophysical Union.
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| 3. |
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| 4. |
- Friel, R. J., 1982-, et al.
(författare)
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The effect of interface topography for Ultrasonic Consolidation of aluminium
- 2010
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Ingår i: Journal of Materials Science and Engineering. - New York, NY : David Publishing Company. - 2161-6213 .- 0921-5093. ; 527:16-17, s. 4474-4483
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Tidskriftsartikel (refereegranskat)abstract
- Ultrasonic Consolidation (UC) is an additive manufacturing technology which is based on the sequential solid-state ultrasonic welding of metal foils. UC presents a rapid and adaptive alternative process, to other metal-matrix embedding technologies, for 'smart' metal composite material production. A challenge that exists however relates to optimising, for bond density and plastic flow, the interlaminar textures themselves that serve as the contact surfaces between the foils.UC employs a sonotrode connected to a transducer to exude ultrasonic energy into the metal foil being sequentially deposited. This sonotrode to metal contact imparts a noteworthy topology to the processed metals surface that in turn becomes the crucial substrate topology of the subsequent layers deposition. This work investigated UC processed Al 3003 samples to ascertain the effect of this imparted topology on subsequent layer deposition. Surface and interlaminar topology profiles were characterised using interferometry, electron and light microscopy. The physical effect of the topology profiles was quantified via the use of peel testing.The imparted topology profile was found to be of fundamental significance to the mechanical performance and bond density achieved within the bulk laminate during UC. The UC process parameters and sonotrode topology performed a key role in modifying this topology profile. The concept of using a specifically textured sonotrode to attain desired future smart material performance via UC is proposed by the authors. © 2010 Elsevier B.V.
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| 5. |
- Schwope, L-A, et al.
(författare)
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Field repair and replacement part fabrication of military components using ultrasonic consolidation cold metal deposition
- 2009
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Ingår i: NATO Science and Technology Organization. ; , s. 22-1-22-12
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Konferensbidrag (refereegranskat)abstract
- Timely repair and replacement of military components without degrading material properties offers tremendous opportunities for cost and schedule savings on a number of military platforms. Effective field-based additive manufacturing repair approaches have proven difficult to develop, as conventional additive metal deposition technologies typically include a molten phase transformation and controlled inert deposition environments. The molten stage of laser and electron beam based additive processes unfortunately results in large dimensional and microstructural changes to the component being repaired or re-fabricated. As a result, high residual stresses and unpredictable ductility profiles in the repair area, or the re-fabricated part, make the final product unsafe for redeployment. Specifically, the heat affected zone associated with traditional deposition-based repair methods can produce a low strength, non-homogenous region at the joint; these changes in the materials properties of the repaired parts are detrimental to the fatigue life, and are a major concern where cyclic loading is experienced. The use of solid state high power Ultrasonic Consolidation (UC) technologies avoids the liquid-solid transition complexity and creates a predictable “cold” bond. This method then allows for strong, homogenous structures to be manufactured and repaired in the field and opens the door for the use of high strength repair material that may reduce the frequency of future failure itself. In addition, UC further offers the opportunity to provide enhanced functionality and ruggedness to a component either during repair or from original manufacture by allowing the embedding of passive and functional elements into the new fabricated component or feature.
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| 6. |
- Elbe, A.-M., et al.
(författare)
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Career and Employment Survey for the Former Students of the European Master’s Programme in Sport and Exercise Psychology
- 2009
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Ingår i: Congrès International de Psychologie du Sport, Vincennes, 1-3 juillet 2009. - Paris : Institut National du Sport, de l'Expertise et de la Performance (INSEP). ; , s. 121-121
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of the European Master’s Programme in Sport and Exercise Psychology (EMPSEP) is to pool expertise of 12 European universities within one Master’s programme (see http://www.fepsac.com/). The 60 ECTS European programme provides students with advanced knowledge and skills. The EMPSEP comprises a joint intensive course, a study module similar in all the participating universities, lectures and seminars, a Master’s thesis, and a mobility period of 4-5 months at an EMPSEP host university. Ten years after the graduation of the first students the EMPSEP consortium conducted an online survey. Seventy of the invited 174 former students participated in the study (mean age 31.5 years, SD= 4.7). The aim of the survey was to discover the participants’ employment status and how their participation in the master’s program was related to this. Results indicate that 86% of the participants have started working since they completed their degree. Forty percent of those participants who have started working in their first job have managed to receive a permanent position, 27% a fixed term or temporary job, 25% a part time job, 6% are self employed and 1 person (2%) was employed by subsidies in his/ her first job after graduation. On a scale from extremely dissatisfied (1) to extremely satisfied (6), the participants rated their satisfaction with the program in relation to their career as 4.72 (SD=1.13) on average. Sixty nine of the participants felt that they had benefited from the international network provided by the students and teachers within the programme, and 94% would recommend the European Master’s program to other students in their field.
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