11,735 research outputs found
The importance of GRM gravity observations in continental regions
Altimetric satellites showed the existence of gravity anomalies with wavelengths between 1500 km and 3000 km which correlated with residual depth anomalies. It was suggested that there is also an even smaller scale convective circulation with a wavelength of less than 500 km. Numerical experiments and SEASAT profiles demonstrate that similar small scale circulation must also exist near fracture zones. The mantle therefore must contain at least three scales of circulation: (1) comparable to the plate dimensions, the large scale circulation, which returns material from the Island arcs to the ridges; (2) an intermediate scale comparable to the depth of the upper mantle; and (3) a small scale comparable to the thickness of the asthenosphere. This picture was established by observations of gravity and bathymetry in oceanic regions
Tommy Prince: Warrior
Over the last decade, there has been a flurry of interest in the Aboriginal men and women who served in the world wars and Korea. No one is more famous than Sergeant Thomas George Prince, MM (1919–77), one of the most decorated non-commissioned officers in Canadian military history. Yet he remains, to most Canadians, an unknown figure
Who is coming from Vanuatu to New Zealand under the new Recognised Seasonal Employer (RSE) program?
New Zealand’s new Recognised Seasonal Employer (RSE) program allows workers from the Pacific Islands to come to New Zealand for up to seven months to work in the horticulture and viticulture industries. One of the explicit objectives of the program is to encourage economic development in the Pacific. In this paper we report on the results of a baseline survey taken in Vanuatu, which allows us to
examine who wants to participate in the program, and who is selected amongst those interested. We find the main participants are males in their late 20s to early
40s, most of whom are married and have children. Most workers are subsistence farmers in Vanuatu and have not completed more than 10 years of schooling. Such
workers would be unlikely to be accepted under existing migration channels. Nevertheless, we find RSE workers from Vanuatu to come from wealthier households, and have better English literacy and health than individuals not applying
for the program. Lack of knowledge about the policy and the costs of applying appear to be the main barriers preventing poorer individuals applying
Antiferromagnetism and Superconductivity in layered organic conductors: Variational cluster approach
The -(ET)X layered conductors (where ET stands for BEDT-TTF) are
studied within the dimer model as a function of the diagonal hopping
and Hubbard repulsion . Antiferromagnetism and d-wave superconductivity are
investigated at zero temperature using variational cluster perturbation theory
(V-CPT). For large , N\'eel antiferromagnetism exists for ,
with . For fixed , as is decreased (or pressure
increased), a superconducting phase appears. When is
decreased further, the a order takes over. There is a critical value
of of beyond which the AF and dSC phases are separated
by Mott disordered phase.Comment: 4 pages, 4 figures. Investigation of the d_xy phase added +
discussion of gap symmetr
Instabilities in decelerating supersonic flows with applications to cosmic ray shocks
The nature of instabilities in cosmic ray shocks is investigated by using two distinct models for the shock wave. For wavelengths which are short relative to the thickness of the shock wave, the shock is treated as a smoothly decelerating low, and an appropriate JWKB type expansion is used to describe the perturbations to the flow. In this, the short wavelength regime, the presence of squeezing and an effective g renders strong cosmic ray shocks unstable in a way which is similar to instabilities in other supersonic flows, such as in de Laval nozzle flow or a heat conduction dominated shock wave. In the long wavelength limit, where the shock is treated as a discontinuous transition, a stability function is derived which, if negative, corresponds to unstable disturbances growing exponentially in time. In this case, it was found that if the cosmic ray fluid is relativistic (gamma sub c = 4/3) and the background plasma ideal (gamma = 5/3), then strong shocks are unstable
Two-photon excitation of nitric oxide fluorescence as a temperature indicator in unsteady gas-dynamic processes
A laser induced fluorescence technique, suitable for measuring fluctuating temperatures in cold turbulent flows containing very low concentrations of nitric oxide is described. Temperatures below 300 K may be resolved with signal to noise ratios greater than 50 to 1 using high peak power, tunable dye lasers. The method relies on the two photon excitation of selected ro-vibronic transitions. The analysis includes the effects of fluorescence quenching and shows the technique to be effective at all densities below ambient. Signal to noise ratio estimates are based on a preliminary measurement of the two photon absorptivity for a selected rotational transition in the NO gamma (0,0) band
The two-photon absorptivity of rotational transitions in the A2 Sigma hyperon + (v prime = O) - X-2 pion (v prime prime = O) gamma band of nitric oxide
A predominantly single-mode pulsed dye laser system giving a well characterized spatial and temporal output suitable for absolute two-photon absorptivity measurements was used to study the NO gamma(0,0) S11 + R21 (J double prime = 7-1/2) transition. Using a calibrated induced-fluorescence technique, an absorptivity parameter of 2.8 + or - 1.4 x 10 to the minus 51st power cm to the 6th power was obtained. Relative strengths of other rotational transitions in the gamma(0,0) band were also measured and shown to compare well with predicted values in all cases except the O12 (J double prime = 10-1/2) transition
Optical measurements of fluctuating temperatures in a supersonic turbulent flow using one- and two-photon, laser-induced fluorescence
A laser-induced fluorescence technique was developed that provides a practical means of nonintrusively measuring the instantaneous temperatures in low-temperature turbulent flows. The capabilities of the method are reviewed, and its application to a simple, two-dimensional, turbulent boundary-layer flow at Mach 2 is reported. Measurements of the average temperature distribution through the boundary layer and the magnitudes of temperature fluctuations about their average values are presented
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