Druck-Materie 20b.qxd - JUWEL - Forschungszentrum Jülich

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• Nine spontaneous burps were observed in body ice samples, four of which occurred when >145-148 J/g was stored. Five burps occurred at lower Q (100 and 138 J/g). Ice samples displayed no burps at T irr > 34 - 35 K. • Beads of ice in argon matrix displayed no spontaneous burp at irradiation time 70 78 80-110 QHe 126 87 144
Due to insufficient number of irradiation runs with hydrates, it is impossible to restore data on saturation time. One only may conclude that it is somewhere around 10-15 hours at irradiation temperature 25-30 K, that is, close to that of pure water ice. Q, J/g 140 120 100 80 60 40 20 0 0 5 10 15 20 25 Time, hours 145 THF methane hydrate ice in Ar Q(t)=115*(1-exp(-t/13)) Figure 10. Stored energy versus irradiation time for hydrates and beads of ice 8.2. Condition for spontaneous and thermally stimulated burps From four experiments with THF hydrates (see in Tables 2 and 5) it can be deduced that this substance behaves similar to pure ice. Duration of burps in THF appeared to be longer than in pure water ice due to slow leading front, see in relevant figures in Appendix. One spontaneous burp occurred in THF hydrate after irradiation for 13 h at temperature 20÷27 K with Q=100 J/g (experiment # 44). Another, longer irradiation at the same temperature (experiment #40) displayed but induced burp with Q=115 J/g. Similar behavior is displayed by methane hydrate. One spontaneous burp occurred at irradiation temperature 20÷25 K after 13 h with Q ∼ 80÷90 J/g (experiment #50). At irradiation temperature >25 K no spontaneous burp was registered even for longer time of irradiation (experiments #51, 53), see in Table 2a and 5 and plots of burps. As distinct from pure water ice when both spontaneous and induced burps were equally fast (or no burp occurred), induced burps in hydrates had a long leading front. Finally, one may conclude that spontaneous burps occur in hydrates of THF and methane at irradiation temperature around 20 K and stored energy ≥ 80-100 J/g, absorbed dose > 5.1 MGy, accordingly. Temperature limit of spontaneous burping is near to 25K. Total combination of experimental data on ice and hydrates samples points to an existence of effect of «amorphous» state of ice (hydrates can be considered also as pure ice with defects) on both production of stabilized radicals and their critical concentration.
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ACoM - 6 6th 6 International Worksh
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Forschungszentrum Jülich GmbH Inst
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Preface These are the Proceedings o
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List of participants, cont’d. Kü
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Pepe M. 43 Petriw S. 43 Picton D.J.
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Experimental background, results an
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• Light water ice as H(H2O) at T
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In Table 2 a survey is given about
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sigma-T in barns/molecule Figure 4.
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2.3 Liquid water Compared to the so
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presented. The corresponding experi
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3.2 Gaseous hydrogen and deuterium
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Rho(Omega) normalised 160 140 120 1
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elatively free and can also suffer
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Figure 16. Heat Capacity for Solid
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o-D2 and p-H2 at 5K for an ucn ener
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Figure 22. UCN Upscattering Rates i
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ho(omega) normalised 40 35 30 25 20
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derived from Walker [52]. The neutr
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Since there is only a small gain of
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7. CALCULATION OF SCATTERING LAW DA
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For the validation of these data se
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[36] Nielsen, M.: Phonons in Solid
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2. THE CASE OF MOLECULAR SOLIDS An
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γ r ( 0) ≅ 2 2 2 T erf e ( ) / 2
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4. PRELIMINARY APPLICATION Solid Me
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[5] Meeting on Moderator Concepts a
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state. Conversely, the monatomic hy
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Note that the equilibrium trihydrog
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para hydrogen system under irradiat
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[12] T. E. Fessler and J. W. Blue,
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tion of neutron intensities, partic
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varied between calculations but the
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5. THE OPTIMISATION OF MULTIPLY GRO
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Figure 7. A comparison of time dist
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4.8 cm hydrogen slab in front of a
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ACoM - 6 6 th Meeting of the Collab
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the moderator is annealed every 12
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The method requires two additional
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ABSTRACT ACoM - 6 6 th Meeting of t
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Heat transfer processes across phas
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3. TWO-PHASE FLOW PATTERN IN THE MO
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continuous phase dominating, and a
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Also the velocity pattern has chang
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Figure 8. Methane pellets concentra
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ACoM - 6 6 th Meeting of the Collab
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sample volume and the nominal densi
Page 97 and 98: The results presented in this paper
Page 99: Table 10. Summary of energy transfe
Page 102 and 103: 2. EXPERIMENTAL Methane hydrate was
Page 104 and 105: Figure 4. Energy levels of methane
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Page 108 and 109: phase transitions from phase II to
Page 110 and 111: After melting phase I in the cryost
Page 112 and 113: 4. SOLID PHASES OF MESITYLENE-D0 AN
Page 114 and 115: G(ν) [a.u.] 8 6 4 2 Phase II Phase
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Page 118 and 119: A not quite as perfect cold spectru
Page 120 and 121: 2.2 Inelastic neutron scattering Th
Page 122 and 123: Figure 4. Inelastic spectra at the
Page 124 and 125: 3.2 Moderator performance The resul
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Page 128 and 129: Figure 2. The methane pelletizer, m
Page 130 and 131: Figure 5. The cryogenic hopper fill
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Page 134 and 135: ture
Page 136 and 137: The charging device scheme could be
Page 138 and 139: Table 1. Data of irradiation of met
Page 140 and 141: 5. METHODS OF PROCESSING OF RAW EXP
Page 142 and 143: of radicals, that is, before a burp
Page 144 and 145: 6.2 Condition for thermally stimula
Page 146 and 147: Table 4. Estimated values of an ene
Page 150 and 151: APPENDIX Some useful relations and
Page 152 and 153: APPENDIX. Graphs of burps. 148
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Page 160 and 161: 2. EXPERIMENTAL SETUP Fig. 1 will g
Page 162 and 163: All these parameters are kept const
Page 164 and 165: 4. CONCLUSIONS We demonstrated that
Page 166 and 167: JESSICA (Juelich Experimental Spall
Page 168 and 169: The moderator system consists of th
Page 170 and 171: to change the temperatures and to p
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Page 174 and 175: supplied from the high pressure bom
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Page 180 and 181: 2. TIME OF FLIGHT SPECTRA AND ENERG
Page 182 and 183: When applying this transformation t
Page 184 and 185: data were analyzed in more detail.
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Page 188 and 189: First of all, we should conclude th
Page 190 and 191: The equation (a) may also describe
Page 192 and 193: Even at h=0.01 mm which is too smal
Page 194 and 195: model and some consequences of its
Page 196 and 197: methane and 0.7-1.5% for water ice
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case: the sample of infinite size.
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Phase Diagram of the CH4-H20 system
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Reaction Chamber for Hydrate Produc
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Analysis: X-ray diffraction pattern
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Comparison with non-hydrate forming
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Mechanical Tests: Apparatus 220
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Morphology of Indium Jacket 222
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Schriften des Forschungszentrums J
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Schriften des Forschungszentrums J
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