21,759 research outputs found
Analytical and experimental investigation of a 1/8-scale dynamic model of the shuttle orbiter. Volume 3A: Supporting data
For abstract, see N75-15681
Analytical and experimental investigation of a 1/8-scale dynamic model of the shuttle orbiter. Volume 1: Summary report
A 1/8-scale structural dynamics model of the space shuttle orbiter was analyzed using the NASA Structural Analysis System (NASTRAN). Comparison of the calculated eigenvalues with preliminary test data for the unrestrained condition indicate that the analytical model was consistently stiffer, being about 20% higher in the first mode. The eigenvectors show reasonably good agreement with test data. A series of analytical and experimental investigations undertaken to resolve the discrepancy are described. Modifications in the NASTRAN model based upon these investigations resulted in close agreement for both eigenvalues and eigenvectors
Symptoms of nutrient deficiencies in rape
Rape is a relatively new crop in Western Australia and this investigation was undertaken to produce visual symptoms of nutrient deficiencies so that they could be recorded and used for diagnosing deficiencies in the field. The appearance of mineral deficiency symptoms can vary considerably with growing conditions, so that symptoms produced in a glasshouse are only a guide to the probable symptoms in the field
Nitrogen and phosphorus compound fertilisers
Nitrogen and phosphorus are two vitally important elements for plant growth which are deficient in most soils throughout Western Australia\u27s agricultural areas.
Both nitrogen and phosphorus can also be applied in appropriate compound fertilisers which can be drilled with the seed, thus making their handling much easier. However, excessively high rates can depress plant emergence and may lower crop yields
A Comparison of the High-Frequency Magnetic Fluctuations in Insulating and Superconducting La2-xSrxCuO4
Inelastic neutron scattering performed at a spallation source is used to make
absolute measurements of the dynamic susceptibility of insulating La2CuO4 and
superconducting La2-xSrxCuO4 over the energy range 15<EN<350 meV. The effect of
Sr doping on the magnetic excitations is to cause a large broadening in
wavevector and a substantial change in the spectrum of the local spin
fluctuations. Comparison of the two compositions reveals a new energy scale of
22 meV in La1.86Sr0.14CuO4.Comment: RevTex, 7 Pages, 4 postscript figure
Measurement of Newtonian fluid slip using a torsional ultrasonic oscillator
The composite torsional ultrasonic oscillator, a versatile experimental
system, can be used to investigate slip of Newtonian fluid at a smooth surface.
A rigorous analysis of slip-dependent damping for the oscillator is presented.
Initially, the phenomenon of finite surface slip and the slip length are
considered for a half-space of Newtonian fluid in contact with a smooth,
oscillating solid surface. Definitions are revisited and clarified in light of
inconsistencies in the literature. We point out that, in general oscillating
flows, Navier's slip length b is a complex number. An intuitive velocity
discontinuity parameter of unrestricted phase is used to describe the effect of
slip on measurement of viscous shear damping. The analysis is applied to the
composite oscillator and preliminary experimental work for a 40 kHz oscillator
is presented. The Non-Slip Boundary Condition (NSBC) has been verified for a
hydrophobic surface in water to within ~60 nm of |b|=0 nm. Experiments were
carried out at shear rate amplitudes between 230 and 6800 /s, corresponding to
linear displacement amplitudes between 3.2 and 96 nm.Comment: Revised with minor edits for revie
Stubble burning helps control Wimmera rye grass
In a trial at Wongan Hills Research Station, burning of wheat stubbie in a continuous cropping system, helped to control Wimmera Rye Grass in the crop and resulted in yields up to 25 bushels an acre higher than where the stubble was ploughed in.
WIMMERA RYE GRASS is the most widely used annual pasture grass in the agricultural areas of Western Australia.
It has proved valuable for sheep feed where legume pastures are not grown.
However, it has often proved a serious weed in cereal crops, causing large yield reductions
- …