10,544 research outputs found
High-temperature gas/liquid stress relaxometers
Two relaxometers allow testing of elastomers in various fluids. First relaxometer uses fork-like loading spacer interposed between loading lever and support ring, so that sample is stretched predetermined amount. In second relaxometer, degree of initial elongation is set by means of adjustable collar, which, when locked in place on piston rod, enables sample to be stretched predetermined length
Strain gauge sensitivity improved by using a composite beam
Composite beam connected to strain gauge and mounted on test specimen is capable of amplifying small strains by factor of 10. Tests indicate that resulting output can be 10 times greater than standard method
Optimization of Design of Space Experiments from the Standpoint of Data Processing Semiannual Report, May 1 - Oct. 31, 1966
Encoding algorithm for processing data from space experiment
Optimization of design of space experiments from the standpoint of data processing Semiannual report, 1 Oct. 1967 - 31 Mar. 1968
Design and construction work on spacecraft array processor for onboard processing of experimental dat
Studies on Ethylene Oxide-freon 12 Decontamination and Dry-Heat Sterilization Cycles
Ethylene oxide-Freon decontamination and heat sterilization cycle
Effects of ethylene oxide-Freon 12 decontamination and dry heat sterilization procedures on polymeric products
Effects of ethylene oxide-Freon 12 decontamination and dry heat sterilization procedures on potential spacecraft polymeric material
Long-term aging of elastomers: Chemical stress relaxation of fluorosilicone rubber and other studies
Aerospace applications of elastomers are considered, including: propellant binders, bladder materials for liquid propellant expulsion systems, and fuel tank sealants for high-speed aircraft. A comprehensive molecular theory for mechanical properties of these materials has been developed but has only been tested experimentally in cases where chemical degradation processes are excluded. Hence, a study is being conducted to ascertain the nature, extent, and rate of chemical changes that take place in some elastomers of interest. Chemical changes that may take place in the fluorosilicone elastomer, LS 420, which is regarded as a fuel and high-temperature-resistant rubber are investigated. The kinetic analysis of the chemical stress relaxation and gel permeation chromatography studies comprise the major portion of the report
A Monte Carlo Method for Fermion Systems Coupled with Classical Degrees of Freedom
A new Monte Carlo method is proposed for fermion systems interacting with
classical degrees of freedom. To obtain a weight for each Monte Carlo sample
with a fixed configuration of classical variables, the moment expansion of the
density of states by Chebyshev polynomials is applied instead of the direct
diagonalization of the fermion Hamiltonian. This reduces a cpu time to scale as
compared to for the
diagonalization in the conventional technique; is the dimension
of the Hamiltonian. Another advantage of this method is that parallel
computation with high efficiency is possible. These significantly save total
cpu times of Monte Carlo calculations because the calculation of a Monte Carlo
weight is the bottleneck part. The method is applied to the double-exchange
model as an example. The benchmark results show that it is possible to make a
systematic investigation using a system-size scaling even in three dimensions
within a realistic cpu timescale.Comment: 6 pages including 4 figure
Formation and decay of electron-hole droplets in diamond
We study the formation and decay of electron-hole droplets in diamonds at
both low and high temperatures under different excitations by master equations.
The calculation reveals that at low temperature the kinetics of the system
behaves as in direct-gap semiconductors, whereas at high temperature it shows
metastability as in traditional indirect-gap semiconductors. Our results at low
temperature are consistent with the experimental findings by Nagai {\em et al.}
[Phys. Rev. B {\bf 68}, 081202 (R) (2003)]. The kinetics of the e-h system in
diamonds at high temperature under both low and high excitations is also
predicted.Comment: 7 pages, 8 figures, revised with some modifications in physics
discussion, to be published in PR
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