Thesis - Oztek_Muzaffer_T_200508_MA

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was monitored with two Omega type px602 pressure transducers with a range up to 13.6 atm. The schematic of the complete setup is given in Figure 6. Pressure data were acquired with a Dell 4200 PC using LabView software using a National Instruments board. Thermal data were directly transferred to the PC from the DSC and analyzed using Setsoft 2000 software. The amount of hydrogen absorbed or released was calculated and graphed using SigmaPlot software. This DSC allowed thermal and pressure measurements to be made under static or flowing conditions at pressures as high as 136 atm and temperatures up to 773 K. Sample boats for the DSC were made from 316 stainless steel. The samples loaded into the boat were placed into a hollow glass tube that was sealed at both ends with plastic caps and then transferred from the glove box to the DSC to prevent exposure of the samples to air. Sample cell volume was determined by a water displacement method. Lateral heat loss compensation curves were previously determined. P Reference Cell Feed Gas Inlet Valves Quick Disconnects DSC Furnace Quick Disconnects Exit Valves P Sample Cell Figure 6. Schematic representation of the DSC setup. P denotes pressure transducer. 26
2.2.1.1. Hydriding and Dehydriding Procedures Samples for hydriding trials were prepared by loading 100 to 300 milligrams of sample into sample boats under an argon atmosphere in the glove box. The boats were transferred to the DSC after the furnace temperature had been adjusted to between 10 to 25 °C. The boat was loaded into the cell under a minimal hydrogen flow, which avoided blowing the samples out of the boat and limited air exposure of the samples. After inserting the boat, the exit valves were closed, the system was adjusted to the desired pressure and then the upstream valves and the hydrogen source cylinder valve were closed. The hydriding of the sample was performed either isothermally or with increasing temperature. Constant temperature hydriding was used for samples that took up hydrogen at ambient or sub-ambient temperatures. In this procedure, pressure and thermal data recording started immediately after the system was closed. The furnace temperature was held constant for the entire experiment period. Samples that would only hydride at higher temperatures were subjected to the increasing temperature hydriding procedure. After the sample was inserted and the desired pressure over it had been established, the furnace was held at the initial temperature (T 1 ) for 180 seconds. Then the temperature was increased at a rate of either 5 °C/min or 3 °C/min, up to the previously set final temperature (T 2 ). The furnace was held at the final temperature for 180 seconds and then cooled at a rate of 10 °C/min, down to ambient temperature. Pressure data acquisition started at the beginning of the heating phase. 27
Page 1 and 2: RECOVERY OF HYDROGEN AND HELIUM FRO
Page 3 and 4: ABSTRACT Waste streams of hydrogen
Page 5 and 6: I dedicate this work to my family m
Page 7 and 8: I also would like to cheer for my f
Page 9 and 10: 2.2.2.1. Hydriding and Dehydriding
Page 11 and 12: LIST OF FIGURES Figure 1. Pressure-
Page 13 and 14: Figure 34. Pressure profiles under
Page 15 and 16: 1. INTRODUCTION The focus of this s
Page 17 and 18: ecause of the difference in partial
Page 19 and 20: hydrides by dissolving large amount
Page 21 and 22: hydrogen storage alloy has a specif
Page 23 and 24: • Insensitivity to poisoning by i
Page 25 and 26: hydrogen capacity was not reproduci
Page 27 and 28: showed the lowest plateau pressure
Page 29 and 30: grain boundaries increases the tota
Page 31 and 32: These parameters are generally inte
Page 33 and 34: Figure 4. CaCu5-type P6/mmm structu
Page 35 and 36: In this study, the addition of Al t
Page 37 and 38: 2. EXPERIMENTAL 2.1.Chemicals and R
Page 39: Figure 5. The high energy Spex 8000
Page 43 and 44: approximately 5 atm, and heating th
Page 45 and 46: determined by the start and end of
Page 47 and 48: 450 400 coating thickness (Å) 350
Page 49 and 50: 3. RESULTS AND DISCUSSIONS 3.1. Hyd
Page 51 and 52: DSC 111 heat flow/mW Exo 300 Figure
Page 53 and 54: The thermogram associated with the
Page 55 and 56: total time was broken into three 30
Page 57 and 58: The VTiNi sample was subjected to d
Page 59 and 60: solid solution of hydrogen rather t
Page 61 and 62: DSC 111 Heat Flow/mW 180 Exo Figure
Page 63 and 64: 100 rpm setting, the milling vial w
Page 65 and 66: BPR, 400 rpm, 5 minutes) did not re
Page 67 and 68: Table 1: Effects of various milling
Page 69 and 70: Due to the fast kinetics observed a
Page 71 and 72: The mole % Al after milling was les
Page 73 and 74: Figure 24: Percent hydrogen capacit
Page 75 and 76: the start of the heating period, wh
Page 77 and 78: However, it was noted that the part
Page 79 and 80: percent hydrogen was decreased. The
Page 81 and 82: 3.2.2.4. AuPd and Pt Coating on LaN
Page 83 and 84: 1.0 0.8 (a) (b) Wt. % H absorbed 0.
Page 85 and 86: After dehydriding by the sample, th
Page 87 and 88: 19 18 P (atm) 17 16 15 14 0.74 %Al
Page 89 and 90: GC output, arbitrary units 0 5 10 1
Page 91 and 92:
sample was LaNi 5 . This may indica
Page 93 and 94:
30 min. 15 min. Intensity (arb. uni
Page 95 and 96:
After milling the percentages of Al
Page 97 and 98:
4. CONCLUSIONS This study has been
Page 99 and 100:
16. Van-Vucht, J.H.N., Kuijpers, F.
Page 101 and 102:
47. Suryanarayana, C., Progress in
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