High temperature compositions Patent

Method for producing refractory molybdenum disilicide

Spectroscopic analysis of radiation-generated changes in tensile properties of a polyetherimide film

The effects of electron radiation on Ultem, a polyetherimide were studied for doses from 2 x 10 to the 9th power to 6 x 10 to the 9th power rad. Specimens were studied for tensile property testing and for electron paramagnetic resonance and infrared spectroscopic measurements of molecular structure. A Faraday cup design and a method for remote temperature measurement were developed. The spectroscopic data show that radiation caused dehydrogenation of methyl groups, rupture of main-chain ether linkage, and opening of imide rings, all to form radicals and indicate that the so-formed atomic hydrogen attached to phenyl radicals, but not to phenoxyl radicals, which would have formed hydroxyls. The observed decays of the radiation-generated phenoxyl, gem-dimethyl, and carbonyl radicals were interpreted as a combining of the radicals to form crosslinking. This crosslinking is the probable cause of the major reduction in the elongation of the tensile specimens after irradiation. Subsequent classical solubility tests indicate that the irradiation caused massive crosslinking

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 simplified holographic-interferometry technique for real-time flow visualization and analysis

A holographic-interferometry technique for flow visualization and analysis that produces real-time moire fringes is described from both experimental and application considerations. It has three chief advantages: real-time data for continuous observation and photography, ease of optical adjustment, and capability of using ordinary-glass test-section windows without affecting the results. A theoretical discussion is presented describing the formation of the fringes in holographic terms and then comparing this result to that which is obtained from a conventional moire approach. A discussion on obtaining density information from the fringe pattern is also included

Dual frequency receiver system for Mariner 1967 to Venus Final engineering report

Dual frequency receiver system for inclusion in Mariner 1967 spacecraft payload for use in measuring Venusian ionosphere and atmosphere by radio occultatio

Post-operative cranial pressure monitoring system

System for monitoring of fluidic pressures in cranial cavity uses a miniaturized pressure sensing transducer, combined with suitable amplification means, a meter with scale calibrated in terms of pressures between minus 100 and plus 900 millimeters of water, and a miniaturized chart recorder covering similar range of pressures

The magnetic structure of Gd_2Ti_2O_7

We attempt to solve the magnetic structure of the gadolinium analogue of `spin-ice', using a mixture of experimental and theoretical assumptions. The eventual predictions are essentially consistent with both the Mossbauer and neutron measurements but are unrelated to previous proposals. We find two possible distinct states, one of which is coplanar and the other is fully three-dimensional. We predict that close to the initial transition the preferred state is coplanar but that at the lowest temperature the ground-state becomes fully three-dimensional. Unfortunately the energetics are consequently complicated. There is a dominant nearest-neighbour Heisenberg interaction but then a compromise solution for lifting the final degeneracy resulting from a competition between longer-range Heisenberg interactions and direct dipolar interactions on similar energy scales.Comment: 12 pages, 15 figure

Rapid Manufactured Textiles

Rapid Manufacturing (RM) is increasingly becoming a viable manufacturing process due to dramatic advantages that are achievable in the area of design complexity. Through the exploration of the design freedom, this paper introduces the concept of manufacturing textiles for potential smart and high performance textile applications. This paper discusses the current limitations associated with the manufacture of textiles through RM and presents a novel methodology for the generation of 3D conformal RM textile articles. The paper concludes that through RM it is entirely possible to manufacture a structure that incorporates drape and free movement properties directly comparable to conventional textiles.Mechanical Engineerin

Inhibition of histone deacetylase as a treatment for cardiac hypertrophy

The present invention provides for methods of treating and preventing cardiac hypertrophy. Class II HDACs, which are known to participate in regulation of chromatin structure and gene expression, have been shown to have beneficial effects on cardiac hypertrophy. Surprisingly, the present invention demonstrates that HDAC inhibitors inhibit cardiac hypertrophy by inhibiting fetal cardiac gene expression and interfering with sarcomeric organization.Board of Regents, University of Texas Syste