| 1. |
- Frisk, Karin, et al.
(author)
-
Characterisation of EBM-built shelled samples of Ti6Al4V compacted by HIP
- 2016
-
In: World PM 2016 Congress and Exhibition. - : European Powder Metallurgy Association (EPMA). - 9781899072484
-
Conference paper (peer-reviewed)abstract
- Compaction of additively manufactured Ti6Al4V components by Hot Isostatic Pressing (HIP) is often applied to eliminate porosity, producing fully dense material. In the present work shelled samples produced by Electron Beam Melting with the Arcam process (EBM) were compacted by HIP to produce fully dense samples. Cylindrical samples were studied. The walls of the cylinders were built with EBM, and the powder from the process was left uncompacted inside the cylinders. Samples with different wall thicknesses were produced. The samples were thereafter subjected to a HIP compaction. The critical wall thicknesses needed for compaction were evaluated, and the microstructures characterized. The results show that fully dense samples, with very fine microstructures, are possible.
|
|
| 2. |
- Larsson, Bengt, et al.
(author)
-
Molecular oxygen in the rho Ophiuchi cloud
- 2007
-
In: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 466:3, s. 5-
-
Journal article (peer-reviewed)abstract
- Context: Molecular oxygen, O2, has been expected historically to be an abundant component of the chemical species in molecular clouds and, as such, an important coolant of the dense interstellar medium. However, a number of attempts from both ground and from space have failed to detect O2 emission.Aims: The work described here uses heterodyne spectroscopy from space to search for molecular oxygen in the interstellar medium. Methods: The Odin satellite carries a 1.1 m sub-millimeter dish and a dedicated 119 GHz receiver for the ground state line of O2. Starting in 2002, the star forming molecular cloud core ρ Oph A was observed with Odin for 34 days during several observing runs.Results: We detect a spectral line at v_LSR =+3.5 km s-1 with Δ v_FWHM=1.5 km s-1, parameters which are also common to other species associated with ρ Oph A. This feature is identified as the O2 (NJ = 11 - 1_0) transition at 118 750.343 MHz.Conclusions: The abundance of molecular oxygen, relative to H{2} , is 5 × 10-8 averaged over the Odin beam. This abundance is consistently lower than previously reported upper limits.Based on observations with Odin, a Swedish-led satellite project funded jointly by the Swedish National Space Board (SNSB), the Canadian Space Agency (CSA), the National Technology Agency of Finland (Tekes) and Centre National d'Étude Spatiale (CNES). The Swedish Space Corporation has been the industrial prime contractor and also is operating the satellite. Appendix A is only available in electronic form at http://www.aanda.org
|
|
| 3. |
- Leicht, Alexander, 1987, et al.
(author)
-
As-HIP microstructure of EBM fabricated shell components
- 2016
-
In: World PM 2016 Congress and Exhibition. - : European Powder Metallurgy Association (EPMA). - 9781899072484
-
Conference paper (peer-reviewed)abstract
- Electron Beam Melting (EBM) was used to build Ti-6Al-4V cylindrical shell samples with different wall thickness filled with powder. Built shell samples were HIPed and the difference in microstructure between the EBM-built walls and densified powder inside the shell components was studied as well as the cohesion between these two regions. Components characterization utilizing LOM and SEM+EBSD indicates that columnar grain growth was consistent before and after HIP in the EBM-built part of the components (walls), whereas the densified material in the center of the component had a fine isotropic microstructure, characteristic for HIPed material. The combination of EBM and HIP is shown to be an attractive way of manufacturing complex-shape full density components for high performance applications, involving shortening of built time in the EBM-processing and lead time in capsule fabrication for HIP.
|
|
| 4. |
- Lundin Frisk, Emrik, 1994, et al.
(author)
-
The geosystem services concept – What is it and can it support subsurface planning?
- 2022
-
In: Ecosystem Services. - : Elsevier BV. - 2212-0416. ; 58
-
Research review (peer-reviewed)abstract
- The subsurface is a multifunctional natural resource. However, a mindset of “out of sight, out of mind” and a first-come-first-served principle are prevalent when accessing these resources, compromising fair intergenerational and intragenerational distribution and sustainable development. As with the ecosystem services (ES) concept, which acknowledges the contribution of the living part of nature to human well-being, the concept of geosystem services (GS) has been suggested as a way to highlight abiotic services and services provided by the subsurface. The overall aim of this study was to review current definitions of GS and their categorisation, and to suggest how the concept of GS can support subsurface planning. A systematic literature review on GS was carried out following the PRISMA protocol drawing from the Scopus database. The emerging picture from the reviewed articles is that the GS concept is both one of novelty and one currently showing inconsistency, with two prominent definitions: A) GS are abiotic services that are the direct result of the planet's geodiversity, independent of the interactions with biotic nature – there is no differentiation between suprasurface and subsurface features, and B) GS provide benefits specifically resulting from the subsurface. Thirty-one out of thirty-nine GS listed in the reviewed literature are included in the abiotic extension of the common ES framework CICES v5.1, but some essential services are omitted. A unified definition of GS is desirable to build a common framework for classifying and describing GS, potentially following the CICES structure for ES. Such a framework can support systematic inclusion of GS in planning processes and contribute to improved subsurface planning. In planning practice, there are examples of important GS that are already included under the ES umbrella because planners are aware of their importance but a comprehensive framework to handle these services is lacking.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Anrup, Roland, et al.
(author)
-
Centrala universitetsvärden hotas av bolagiseringsidén
- 2013
-
In: Dagens nyheter. - 1101-2447.
-
Journal article (pop. science, debate, etc.)abstract
- Högskolestiftelser. Förslaget att driva svenska universitet i stiftelseform öppnar för bolagisering. Men det är ingen riktig utredning, utan en politisk pamflett utan eftertanke. Privatisering av universitet hotar både oberoendet, forskningskvaliteten och samhällsnyttan, skriver 36 forskare vid svenska högskolor och universitet.
|
|
| 8. |
- Antti, Marta-Lena, et al.
(author)
-
Synthesising of a model composite in the oxide/oxide system : alumina fibre reinforced alumina matrix
- 1999
-
In: Advanced structural fiber composites. - : TECHNA Srl. - 8886538235
-
Conference paper (peer-reviewed)abstract
- Ceramic matrix composites have attracted big interest as potential material for high temperature applications. To avoid one of the main problems, namely oxidation at higher temperatures, interest has increased for systems where both reinforcement and matrix material are ceramic oxides. This work presents a possible method of producing long fibre reinforced ceramic matrix composites. The method was applied to single crystal aluminium oxide fibres in a polycrystalline alumina matrix and involves cladding individual fibres with the matrix material in the form of pre-sintered tubes with appropriately small diameter. The composite is then hot isostatically pressed (HIP), by putting several fibre-tube pairs in a container of required diameter. A HIP cycle was found that led to full densification of the composite without visual damage to the fibres. The method produces composites with an ideal uniform fibre spacing; samples of cylindrical shape suitable, for example, for uniaxial testing can be produced
|
|
| 9. |
|
|
| 10. |
- Bengtsson, S., et al.
(author)
-
New Aluminium Alloy Tailored For Powder Bed Fusion - Laser Beam Process
- 2022
-
In: World PM 2022 Congress Proceedings.
-
Conference paper (peer-reviewed)abstract
- The powder bed fusion - laser beam (PBF-LB) process can produce parts with complex geometry. Light weight designs can be created and by using light alloys further weight savings can be achieved. However, minimizing printing defects using standard aluminium alloys, such as 2000, 6000 and 7000 series alloys, have proved to be difficult since they are all prone to solidification cracking. In the present study, two aluminium alloys are addressed: The first alloy is the AlSi10Mg alloy known for easy printing and consistent quality in PBF-LB printing process. The second material is a novel alloy from self-developed Al-Mn-Cr-Zr family of alloys designed to inherently resist solidification cracking, while also providing strong ageing response. The quality of printing and the resulting mechanical properties are compared. The results show that the new material prints in a robust way and that the mechanical properties are superior to those of AlSi10Mg.
|
|
