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| 2. |
- Acharya, B. S., et al.
(författare)
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Introducing the CTA concept
- 2013
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Ingår i: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 43, s. 3-18
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project. (C) 2013 Elsevier B.V. All rights reserved.
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| 3. |
- Actis, M., et al.
(författare)
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Design concepts for the Cherenkov Telescope Array CTA : an advanced facility for ground-based high-energy gamma-ray astronomy
- 2011
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Ingår i: Experimental astronomy. - : Springer. - 0922-6435 .- 1572-9508. ; 32:3, s. 193-316
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Tidskriftsartikel (refereegranskat)abstract
- Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.
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| 4. |
- Abbasi, R., et al.
(författare)
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Search for neutrino-induced cascades with five years of AMANDA data
- 2011
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Ingår i: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 34:6, s. 420-430
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Tidskriftsartikel (refereegranskat)abstract
- We report on the search for electromagnetic and hadronic showers ("cascades") produced by a diffuse flux of extraterrestrial neutrinos in the AMANDA neutrino telescope. Data for this analysis were recorded during 1001 days of detector livetime in the years 2000-2004. The observed event rates are consistent with the background expectation from atmospheric neutrinos and muons. An upper limit is derived for the diffuse flux of neutrinos of all flavors assuming a flavor ratio of v(e):v(mu):v(tau) = 1:1:1 at the detection site. The all-flavor flux of neutrinos with an energy spectrum Phi proportional to E-2 is less than 5.0 x 10(-7) GeV s(-1) sr(-1) cm(-2) at a 90% C.L. Here, 90% of the simulated signal would fall within the energy range 40 TeV to 9 PeV. We discuss flux limits in the context of several specific models of extraterrestrial and prompt atmospheric neutrino production.
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| 5. |
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| 6. |
- Dudrova, E, et al.
(författare)
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Improvement of Strength Properties of Fe-Cr-Mo-[Cu-Ni]-C Sintered Steels by Sinter-Hardening
- 2010
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Ingår i: World Powder Metallurgy Congress and Exhibition, World PM 2010; Florence; Italy; 10 October 2010 through 14 October 2010. - 9781899072194 ; 3, s. 79-86
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Konferensbidrag (refereegranskat)abstract
- The effect of high temperature sintering and high cooling rate on shifting the microstructure composition to favourably portion of high strength structures and thus strength properties improvement of the Fe-Cr-Mo-[Cu-Ni]-C sintered steels based on Astaloy CrL was investigated. All the systems were processed by both sinter-hardening and conventional sintering. The high temperature vacuum sintering (11800C) was integrated with high (6K/s), medium (3K/s) and slow (0.1K/s) cooling rates; the conventional sintering at 11800C with the cooling rate of ~0.17K/s was carried out in N2-rich atmosphere. Depending on chemical composition, the yield and tensile strengths of 890-1150 MPa and 913 -1230 MPa were achieved by the applied sinter-hardening. All the values are approximately double than those for pearlite/bainite structures after conventional sintering. Finally, basing on the microstructure composition and corresponding microhardness, the (theoretical) tensile strength of the “pore free” matrix was calculated. The difference between calculated and experimental tensile strength values was explained by microfractographic observations.
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| 7. |
- Dudrova, Eva, et al.
(författare)
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MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Fe-Cr-Mo-[Cu-Ni]-C SINTERED STEELS
- 2010
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Ingår i: Acta Metallurgica Slovaca - Conference. - 1338-1660. ; 1, s. 580-585
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Tidskriftsartikel (refereegranskat)abstract
- The effect of high-temperature vacuum sintering (11800C) integrated with high (6K/s), medium (3K/s) and slow (0.1K/s) cooling rates and conventional sintering at 11800C with cooling rate of ~0.17K/s on shifting the microstructural composition to significant portion of martensite-bainite and thus effective improvement of mechanical properties of Fe-Cr-Mo-[Cu-Ni]-C sintered steels (Astaloy Cr+1 and 2% Cu and/or 50% Distaloy AB powder was investigated. In dependence on chemical composition the yield and tensile strengths of 890-1150 MPa and 913-1230 MPa and impact energy of 10-15 J were achieved by sinter-hardening. The yield and tensile strengths were approximately double than those resulting from conventional sintering.
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| 8. |
- Bidulsky, Robert, et al.
(författare)
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The Effect of Manganese on Microstructure Development and Diffusion Characteristics in Admixed Fe-Mn-C Sintered Steels
- 2010
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Ingår i: World Powder Metallurgy Congress and Exhibition, World PM 2010; Florence; Italy; 10 October 2010 through 14 October 2010. - 9781899072125 ; 3, s. 113-120
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Konferensbidrag (refereegranskat)abstract
- The aim of this work is to determine the effect of manganese on the microstructure development of admixed Fe-Mn-C sintered steels, as well as to study the diffusion characteristics of Mn in the Fe matrix. Admixed systems were prepared on the base of sponge iron powder, with addition of 0.3 % C and 3% Mn added as ferromanganese. Sintering was carried out in laboratory tube furnace in an atmosphere of pure gases mixture 25 % N2 + 75 % H2 with the dew point of -30°C. The specimens were sintered at 750, 900, 1050, 1150 and 1200°C for 3 minutes. The obtained microstructures were complex and graded due to the local chemical heterogeneities of these materials with different Mn and C concentration. More detailed investigation reveal that diffusion induced grain boundary migration (DIGM) is the dominant alloying mechanism in sintered manganese steels. On the basis of presented results, Mn apparent diffusion coefficient and penetration depth were calculated.
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