| 1. |
- Kelly, J. J., et al.
(author)
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Recoil polarization measurements for neutral pion electroproduction at Q(2)=1(GeV/c)(2) near the Delta resonance
- 2007
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 75:2
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Journal article (peer-reviewed)abstract
- We measured angular distributions of differential cross section, beam analyzing power, and recoil polarization for neutral pion electroproduction at Q(2)=1.0 (GeV/c)(2) in 10 bins of 1.17 <= W <= 1.35 GeV across the Delta resonance. A total of 16 independent response functions were extracted, of which 12 were observed for the first time. Comparisons with recent model calculations show that response functions governed by real parts of interference products are determined relatively well near the physical mass, W=M-Delta approximate to 1.232 GeV, but the variation among models is large for response functions governed by imaginary parts, and for both types of response functions, the variation increases rapidly with W > M-Delta. We performed a multipole analysis that adjusts suitable subsets of center dot(pi)<= 2 amplitudes with higher partial waves constrained by baseline models. This analysis provides both real and imaginary parts. The fitted multipole amplitudes are nearly model independent-there is very little sensitivity to the choice of baseline model or truncation scheme. By contrast, truncation errors in the traditional Legendre analysis of N ->Delta quadrupole ratios are not negligible. Parabolic fits to the W dependence around M-Delta for the multiple analysis gives values for Re(S1+/M1+)=(-6.61 +/- 0.18)% and Re(E1+/M1+)=(-2.87 +/- 0.19)% for the p pi(0) channel at W=1.232 GeV and Q(2)=1.0 (GeV/c)(2) that are distinctly larger than those from the Legendre analysis of the same data. Similarly, the multipole analysis gives Re(S0+/M1+)=(+7.1 +/- 0.8)% at W=1.232 GeV, consistent with recent models, while the traditional Legendre analysis gives the opposite sign because its truncation errors are quite severe.
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| 2. |
- Rvachev, MM, et al.
(author)
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Quasielastic He-3(e,e(')p)H-2 reaction at Q(2)=1.5 GeV2 for recoil momenta up to 1 GeV/c
- 2005
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In: Physical Review Letters. - 1079-7114. ; 94:19
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Journal article (peer-reviewed)abstract
- We have studied the quasielastic He-3(e,e(')p)H-2 reaction in perpendicular coplanar kinematics, with the energy and the momentum transferred by the electron fixed at 840 MeV and 1502 MeV/c, respectively. The He-3(e,e(')p)H-2 cross section was measured for missing momenta up to 1000 MeV/c, while the A(TL) asymmetry was extracted for missing momenta up to 660 MeV/c. For missing momenta up to 150 MeV/c, the cross section is described by variational calculations using modern He-3 wave functions. For missing momenta from 150 to 750 MeV/c, strong final-state interaction effects are observed. Near 1000 MeV/c, the experimental cross section is more than an order of magnitude larger than predicted by available theories. The A(TL) asymmetry displays characteristic features of broken factorization with a structure that is similar to that generated by available models.
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| 3. |
- Hotta, A., et al.
(author)
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Experimental and Analytical Investigation of Formation and Cooling Phenomena in High Temperature Debris Bed
- 2019
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In: Journal of Nuclear Science and Technology. - : Taylor and Francis Ltd.. - 0022-3131 .- 1881-1248.
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Journal article (peer-reviewed)abstract
- Key phenomena in the cooling states of underwater debris beds were classified based on the premise that a target debris bed has a complicated geometry, nonhomogeneous porosity, and volumetric heat. These configurations may change due to the molten jet breakup, droplet agglomeration, anisotropic melt spreading, two-phase flow in a debris bed, particle self-leveling and penetration of molten metals into a particle bed. Based on these classifications, the modular code system THERMOS was designed for evaluating the cooling states of underwater debris beds. Three tests, DEFOR-A, PULiMS, and REMCOD were carried in six phases to extend the existing database for validating implemented models. Up to Phase-5, the main part of these tests has been completed and the test plan has been modified from the original one due to occurrences of unforeseeable phenomena and changes in test procedures. This paper summarizes the entire test plan and representative data trends prior to starting individual data analyses and validations of specific models that are planned to be performed in the later phases. Also, it tries to timely report research questions to be answered in future works, such as various scales of melt-coolant interactions observed in the shallow pool PULiMS tests.
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| 4. |
- Hoseyni, Seyed Mohsen, et al.
(author)
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Metallic melt infiltration in preheated debris bed and the effect of solidification
- 2021
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In: Nuclear Engineering and Design. - : Elsevier BV. - 0029-5493 .- 1872-759X. ; 379, s. 111229-
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Journal article (peer-reviewed)abstract
- The re-melting of multi-component debris is important for both in-vessel and ex-vessel phases of severe accident progression in nuclear power plants. However, current knowledge is limited with respect to understanding the associated complex phenomena and their interactions. In this paper, the phenomenon of melt infiltration through a porous debris bed with and without solidification is examined by synthesizing the data obtained from ongoing experimental research (REMCOD facility). In this regard, results obtained from 12 experiments are analyzed. Eight tests were conducted for melt infiltration through debris at temperatures above solidification. At this condition, two flow regimes are identified for the melt flow inside the hot porous debris, which is initially dominated by capillary forces and hydrostatic head and then later by the gravity forces. In addition, 4 tests were performed for melt penetration into cold debris where melt infiltration is limited by solidification. It was found that the depth of penetration is correlated with the difference between "sensible heat of melt" and "the amount of heat required to heat the bed up to the melting point of specific melt composition."
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| 5. |
- Noda, H., et al.
(author)
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Development of Evaluation Model for Substation Damage
- 2011
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In: IEEE Transactions on Power Delivery. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8977 .- 1937-4208. ; 26:3, s. 1920-1926
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Journal article (peer-reviewed)abstract
- Society's demand for power is constantly increasing. To overcome the strains, substations are more commonly being built within urban areas. This has its shortcomings, since a substation poses a level of risk. For the first time, the development of an evaluation model for costs associated with substation incidents in urban areas was achieved by Toshiba with the cooperation of the Chalmers University of Technology. This paper discusses an evaluation model for quantifying damages in comparison between a gas-insulated transformer (GIT) and an oil-immersed transformer (OIT) in urban areas. The related damage costs associated with transformer failure during its operation are studied within this paper. The findings from the case study, utilizing a hypothetical scenario setting, were that the damage cost of OIT is in the range of U.S.$1M-$4M and that of the GIT is about U.S.$0.5M-$1.2M.
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