300,119 research outputs found
Space shuttle orbiter vehicle star tracker test program plan
The development model test program was written to provide guidance for essential star tracker test support to the Space Shuttle Orbiter Program. The program organization included test equipment preparation, prototype baseline/acceptance tests, prototype total performance tests, and prototype special tests. Test configurations, preparation phase, documentation, scheduling, and manpower requirements are discussed. The test program permits an early evaluation of the tracker's performance prior to completion and testing of the final flight models
Transfer valve Patent
Three-port transfer valve with one port open continuously suitable for manned space fligh
Respiratory transfer value has fail-safe feature
Quick-acting, remote controlled valve connects either one of two oxygen or air supplies to a breathing tube. The valve, which is fall-safe, incorporates a cammed piston arrangement that is driven by a remote controlled reversible rotary solenoid or reversible electric motor
Asking the experts : developing and validating parental diaries to assess children's minor injuries
The methodological issues involved in parental reporting of events in children's everyday lives are discussed with reference to the development and validation of an incident diary, collecting concurrent data on minor injuries in a community study of children under eight years old. Eighty-two mothers participated in a comparison over nine days of daily telephone interviews and structured incident diaries. Telephone methods resulted in more missing data, and participants in both groups expressed a preference for the diary method. This diary was then validated on a sample of 56 preschool and school-aged children by comparing injury recording by a research health visitor with that of their mothers. Each failed to report some injuries, but there was good agreement overall, and in descriptive data on injuries reported by both. Parental diaries have the potential to provide rich data, of acceptable validity, on minor events in everyday life
The efficiency and the demagnetization field of a general Halbach cylinder
The maximum magnetic efficiency of a general multipole Halbach cylinder of
order is found as function of . The efficiency is shown to decrease for
increasing absolute value of . The optimal ratio between the inner and outer
radius, i.e. the ratio resulting in the most efficient design, is also found as
function of and is shown to tend towards smaller and smaller magnet sizes.
Finally, the demagnetizing field in a general -Halbach cylinder is
calculated, and it is shown that demagnetization is largest either at or . For the common case of a Halbach cylinder
the maximum values of the demagnetizing field is either at at
the outer radius, where the field is always equal to the remanence, or at at the inner radius, where it is the magnitude of the field in the
bore. Thus to avoid demagnetization the coercivity of the magnets must be
larger than these values.Comment: 5 pages, 5 figure
Abundances of Na, Sc, Cr, Mn, Fe, Co, and Cu in 92 meteorites, 9 terrestrial specimens, and 90 individual chondrules Quarterly progress report, 1 Sep. - 30 Nov. 1963
Elemental abundancies in individual chondrules, chondrites and terrestrial matter, whole rock- type meteorites, and carbonaceous chondrite
A simplified, compact static shift register
Shift register was developed which uses only one D type flip-flop and improves packaging density by approximately 25% over the usual arrangement. Circuit is compromise between full master-slave arrangement and dynamic shift register, with limitation only of length of time that clock can be held high during new data entry
Star tracking reticles
A method for the production of reticles, particularly those for use in outer space, where the product is a quartz base coated with highly adherent layers of chromium, chromium-silver, and silver vacuum deposited through a mask, and then coated with an electrodeposit of copper from a copper sulfate solution followed by an electrodeposit of black chromium is described. The masks are produced by coating a beryllium-copper alloy substrate with a positive working photoresist, developing the photoresist, according to a pattern to leave a positive mask, plating uncoated areas with gold, removing the photoresist, coating the substrate with a negative working photoresist, developing the negative working photoresist to expose the base metal of the pattern, and chemically etching the unplated side of the pattern to produce the mask
Polarized quark distributions in nuclear matter
We compute the polarized quark distribution function of a bound nucleon. The
Chiral Quark-Soliton model provides the quark and antiquark substructure of the
nucleon embedded in nuclear matter. Nuclear effects cause significant
modifications to the polarized distributions including an enhancement of the
axial coupling constant.Comment: 5 Pages, 2 Postscript figures, Version to be published in Phys. Rev.
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