Browsing by Author "Kelly, JW"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    The creep of isostatically-pressed beryllium oxide.
    (Australian Atomic Energy Commission, 1967-05) Kelly, JW
    The creep in bending of polycrystalline isostatically-pres sed beryllium oxide has been studied in the temperature range 800°C to 1150°C for stresses up to 104 lb in the minimum creep rate was found to be linearly proportional to stress and the process was temperature — dependent with an activation energy of 100 kcal mole-1. Thus results were consistent with the Nabarro - Herring creep mechanism, the rate constant being 10-8 to 10-9 lb-1 in2 h-1. Probably the creep rate is controlled by an impurity and would be enhanced by neutron irradiation.
  • Thumbnail Image
    Item
    The determination of oxygen in metals using an impulse heating furnace equipped with a sample transfer lock.
    (Australian Atomic Energy Commission, 1975-05) Dale, LS; de Jong, S; Kelly, JW; Whittem, RN
    An impulse heating furnace has been constructed for the determination of low levels of oxygen down to 100 µg g-1 in metals. The furnace is equipped with a sample transfer lock which permits samples to be loaded into outgassed crucibles in a helium atmosphere. As a result, blank levels in the range 2 to 3 µg oxygen are obtained; the modification also results in shorter sample processing time. The apparatus is described, and its suitability for oxygen determinations at these levels has been verified by comparison of results obtained on reference and analysed materials.
  • Thumbnail Image
    Item
    High repetition rate Q-switched CO2 laser.
    (Australian Atomic Energy Commission, 1982-03) Hamilton, N; Kelly, JW; Struve, H
    A rotating mirror Q-switched CO2 laser was designed and constructed for use as an excitation source in infrared fluorescence studies. Output power of 33 W was reached in the continuous wave (CW) mode. In the pulsed mode peak powers of 3 kW and pulse widths of 200 ns FWHM have been measured. The repetition rate may be varied between 275 and 1000 Hz and single line operation is selectable with a diffraction grating. The design is compact and economical. The laser has shown freedom from electrical noise and average power stability of the order of 1 per cent; it has operated reliably for more than 1000 hours with a minimum of maintenance.
  • Thumbnail Image
    Item
    A review of laser isotope separation of uranium hexafluoride
    (Australian Atomic Energy Commission, 1983-04) Kelly, JW
    There is continuing world-wide interest in the possibility of enriching uranium by a laser process which uses uranium hexafluoride. Since no actual commercial plant exists at present this review examines the key areas of related research. It concludes that such a process is feasible that it must employ an adiabatic cooling system with UF6 the minor constituent in a predominantly monatomic or diatomic carrier gas that the necessary infrared and/or ultraviolet-visible lasers are in a state of development bordering on the minimum required and that the economics of such a process appear highly promising.
  • Thumbnail Image
    Item
    Temperature and porosity dependence of the modulus of rigidity and Poisson's ratio of beryllia
    (Australian Atomic Energy Commission, 1967-08) Kelly, JW; Whatham, JF
    Using torsional equipment designed for the task, the modulus of rigidity of isostatically pressed and sintered beryllia was determined as a function of temperature and porosity. The temperature dependance was given by: Gt = G20 (1-at), where Gt is the modulus at toC, G20 is the modulus at 20oC and a is a constant approx. 3 x 10-5 degC independent of porosity up to 800oC. Porosity dependance was given by: Gt = Go (1-bP), where Go is the modulus at zero porosity, P is the fractional volume porosity and b is a constant approx. 1.58 independent of temperature up to 800oC. Poisson's ratio was found to be 0.30 + 0.05 and was independent of both temperature and porosity.
  • Thumbnail Image
    Item
    A thyratron-switched modular CO2 TEA laser for infrared photochemical studies
    (Australian Atomic Energy Commission, 1982-09) Hamilton, N; Kelly, JW; Struve, H
    A thyratron-switched ultraviolet pre-ionised CO2 TEA laser consisting of four modules connected in series has been designed and constructed. The laser can be operated in the TEM 00 mode and is able to produce 2.5 J per pulse. The design and operation of the laser as a tool for infrared studies is discussed together with an evaluation of the effect of operating parameters on output characteristics.