Post Viking planetary protection requirements study

Past planetary quarantine requirements were reviewed in the light of present Viking data to determine the steps necessary to prevent contamination of the Martian surface on future missions. The currently used term planetary protection reflects a broader scope of understanding of the problems involved. Various methods of preventing contamination are discussed in relation to proposed projects, specifically the 1984 Rover Mission

Energy Loss from a Moving Vortex in Superfluid Helium

We present measurements on both energy loss and pinning for a vortex terminating on the curved surface of a cylindrical container. We vary surface roughness, cell diameter, fluid velocity, and temperature. Although energy loss and pinning both arise from interactions between the vortex and the surface, their dependences on the experimental parameters differ, suggesting that different mechanisms govern the two effects. We propose that the energy loss stems from reconnections with a mesh of microscopic vortices that covers the cell wall, while pinning is dominated by other influences such as the local fluid velocity.Comment: 8 pages, 6 figure

Structure of field rotating disturbances in warm plasma

A model in which thermal effects are simulated through use of a multibeam plasma distribution function is developed and investigated to see if solutions which take an initially uniform magnetized plasma to a new uniform state with different field orientation are possible. The momentum conservation integrals are found to admit two classes of such solutions, but only one class exhibits appropriate asymptotic behavior. Extensive numerical integrations have failed to demonstrate the existence of the desired solutions

Dynamics of perpendicular recording heads

3D modeling and inductance measurements were used to design an ultra-high frequency perpendicular system. Kerr microscopy and spin-stand experiments with focused ion beam (FI-B) trimmed perpendicular heads and perpendicular media directly verified the high frequency concepts

Amino acid losses during hemodialysis with infusion of amino acids and glucose

Amino acid losses during hemodialysis with infusion of amino acids and glucose. This study evaluated the effects during hemodialysis of intravenous infusion of amino acids and glucose on plasma amino acid and glucose concentrations and amino acid losses. Eight men undergoing maintenance hemodialysis were each studied during two dialyses using glucose-free dialysate. During one hemodialysis, they were infused with 800ml of normal saline. During the other hemodialysis, they were infused with an equal volume of water which contained 39.5g of essential and non-essential free L-amino acids and 200g of d-glucose. The solutions were infused throughout the dialysis procedure into the drip chamber of the venous outflow from the dialyzer. Subjects were fasted from the night before until the end of hemodialysis, and the order of administration of the two solutions was determined randomly. Plasma essential, non-essential, and total amino acids fell significantly during the infusion of normal saline and rose during the administration of amino acids and glucose. Dialysate total-free amino acid losses averaged 8.2 ± 3.1SDg during the infusion of normal saline and 12.6 ± 3.6g with the administration of amino acids and glucose. These findings indicate that the intravenous infusion of amino acids and glucose during hemodialysis prevents a fall in plasma amino acid and glucose concentrations and leads to only a slight increase in the losses of free amino acids into dialysate. Because most of the infused amino acids are retained, this technique may be used during hemodialysis to avoid a net outflow of amino acids, minimize disruption of amino acid and glucose pools, and provide a nutritional supplement.Pertes en amino-acides au cours de l'hémodialyse avec perfusion d'acides aminés et de glucose. Cette étude a permis d'évaluer les effets de la perfusion intraveineuse d'acides aminés et de glucose pendant l'hémodialyse sur les concentrations plasmatiques d'acides aminés et de glucose, et les pertes d'acides aminés. Huit hommes en hémodialyse chronique ont chacun été étudiés pendant deux dialyses avec un dialysat sans glucose. Pendant une des dialyses ils étaient perfusés avec 800ml de soluté physiologique. Pendant l'hemodialyse autre ils ont infusé avec un égal volume d'eau contenant 39,5g de L-acides aminés libres essentiels ou non, et 200g de d-glucose. Les solutions étaient perfusées pendant la dialyse dans la tubulure veineuse venant du dialyseur. Les malades étaient à jeûn la nuit précédante et jusqu'à la fin de la dialyse, et l'ordre d'administration des deux solutions était déterminé au hasard. Les acides aminés plasmatiques totaux, essentiels et non essentiels ont significativement diminué pendant la perfusion de soluté physiologique, et se sont élevés pendant l'administration d'acides aminés et de glucose. Dans le dialysat, les pertes totales d'acides aminés libres étaient en moyenne de 8,2 ± 3,1g (ds) pendant la perfusion de soluté physiologique, et de 12,6 ± 3,6g lors de l'administration d'acides aminés et de glucose. Ces résultats indiquent que la perfusion intraveineuse d'acides aminés et de glucose au cours de la dialyse empêche la chute des acides aminés et du glucose plasmatiques et n'occasionne qu'une diminution minime des pertes en acides aminés libres dans le dialysat. Puisque la plupart des acides aminés perfusés est retenue, cette technique pourrait être utilisée pendant l'hémodialyse pour éviter une fuite nette d'acides aminés, pour minimiser la dissipation des réserves d'acides aminés et de glucose et pour apporter un supplément nutritif

Slicing of Silicon into Sheet Material. Silicon Sheet Growth Development for the Large Area Silicon Sheet Task of the Low Cost Solar Array Project

The use of multiblade slurry sawing to produce silicon wafers from ingots was investigated. The commercially available state of the art process was improved by 20% in terms of area of silicon wafers produced from an ingot. The process was improved 34% on an experimental basis. Economic analyses presented show that further improvements are necessary to approach the desired wafer costs, mostly reduction in expendable materials costs. Tests which indicate that such reduction is possible are included, although demonstration of such reduction was not completed. A new, large capacity saw was designed and tested. Performance comparable with current equipment (in terms of number of wafers/cm) was demonstrated

Creating a Minimum Data Set on ageing in sub-Saharan Africa

The World Health Organisation, together with representatives of four sub-Saharan African countries (Ghana, South Africa, Tanzania, Zimbabwe) and other stakeholders, launched a project in 1999 to establish a Minimum Data Set on ageing and older persons in Africa. The project focusses on identifying what data are needed to build knowledge on the situation of older Africans and forging the centralised, in-country collation and dissemination of this information. This paper summarises the current state of the project and touches on issues of data availability and quality, while exploring methods for data collection, integration, collation and dissemination

Impact of neutron star oscillations on the accelerating electric field in the polar cap of pulsar: or could we see oscillations of the neutron star after the glitch in pulsar?

Pulsar "standard model", that considers a pulsar as a rotating magnetized conducting sphere surrounded by plasma, is generalized to the case of oscillating star. We developed an algorithm for calculation of the Goldreich-Julian charge density for this case. We consider distortion of the accelerating zone in the polar cap of pulsar by neutron star oscillations. It is shown that for oscillation modes with high harmonic numbers (l,m) changes in the Goldreich-Julian charge density caused by pulsations of neutron star could lead to significant altering of an accelerating electric field in the polar cap of pulsar. In the moderately optimistic scenario, that assumes excitation of the neutron star oscillations by glitches, it could be possible to detect altering of the pulsar radioemission due to modulation of the accelerating field.Comment: 7 pages, 8 figures. Presented at the conference "Isolated Neutron Stars: from the Interior to the Surface", London, April 24-28, 2006; to appear in Astrophysics and Space Scienc