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

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.

Control of Arabidopsis apical-basal embryo polarity by antagonistic transcription factors.

Plants, similarly to animals, form polarized axes during embryogenesis on which cell differentiation and organ patterning programs are orchestrated. During Arabidopsis embryogenesis, establishment of the shoot and root stem cell populations occurs at opposite ends of an apical-basal axis. Recent work has identified the PLETHORA (PLT) genes as master regulators of basal/root fate, whereas the master regulators of apical/shoot fate have remained elusive. Here we show that the PLT1 and PLT2 genes are direct targets of the transcriptional co-repressor TOPLESS (TPL) and that PLT1/2 are necessary for the homeotic conversion of shoots to roots in tpl-1 mutants. Using tpl-1 as a genetic tool, we identify the CLASS III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIP III) transcription factors as master regulators of embryonic apical fate, and show they are sufficient to drive the conversion of the embryonic root pole into a second shoot pole. Furthermore, genetic and misexpression studies show an antagonistic relationship between the PLT and HD-ZIP III genes in specifying the root and shoot poles

A highly miniaturized electron and ion energy spectrometer prototype for the rapid analysis of space plasmas.

MEMS (Micro Electro-Mechanical Systems) plasma analyzers are a promising possibility for future space missions but conventional instrument designs are not necessarily well suited to micro-fabrication. Here, a candidate design for a MEMS-based instrument has been prototyped using electron-discharge machining. The device features 10 electrostatic analyzers that, with a single voltage applied to it, allow five different energies of electron and five different energies of positive ion to be simultaneously sampled. It has been simulated using SIMION and the electron response characteristics tested in an instrument calibration chamber. Small deviations found in the electrode spacing of the as-built prototype were found to have some effect on the electron response characteristics but do not significantly impede its performance

Fluid flow control with transformation media

We introduce a new concept for the manipulation of fluid flow around three-dimensional bodies. Inspired by transformation optics, the concept is based on a mathematical idea of coordinate transformations and physically implemented with anisotropic porous media permeable to the flow of fluids. In two situations - for an impermeable object placed either in a free-flowing fluid or in a fluid-filled porous medium - we show that the object can be coated with an inhomogeneous, anisotropic permeable medium, such as to preserve the flow that would have existed in the absence of the object. The proposed fluid flow cloak eliminates downstream wake and compensates viscous drag, hinting us at the possibility of novel propulsion techniques.Comment: 4 pages, 7 figure

Horizon Report 2009

El informe anual Horizon investiga, identifica y clasifica las tecnologías emergentes que los expertos que lo elaboran prevén tendrán un impacto en la enseñanza aprendizaje, la investigación y la producción creativa en el contexto educativo de la enseñanza superior. También estudia las tendencias clave que permiten prever el uso que se hará de las mismas y los retos que ellos suponen para las aulas. Cada edición identifica seis tecnologías o prácticas. Dos cuyo uso se prevé emergerá en un futuro inmediato (un año o menos) dos que emergerán a medio plazo (en dos o tres años) y dos previstas a más largo plazo (5 años)

The efficiency and the demagnetization field of a general Halbach cylinder

The maximum magnetic efficiency of a general multipole Halbach cylinder of order $p$ is found as function of $p$. The efficiency is shown to decrease for increasing absolute value of $p$. 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 $p$ and is shown to tend towards smaller and smaller magnet sizes. Finally, the demagnetizing field in a general $p$-Halbach cylinder is calculated, and it is shown that demagnetization is largest either at $\cos 2p\phi=1$ or $\cos 2p\phi=-1$. For the common case of a $p=1$ Halbach cylinder the maximum values of the demagnetizing field is either at $\phi = 0,\pi$ at the outer radius, where the field is always equal to the remanence, or at $\phi = \pm \pi/2$ 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

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