88,681 research outputs found
Flight service evaluation of composite components on the Bell helicopter model 206L
This is the second annual report on the flight service components for the Bell Model 206L JetRanger helicopter. The components have been placed in service in the Continental United States, Canada, and Alaska. The report covers the period from 1 August 1983 to 1 January 1986. The status of 34 sets of components is discussed in this report. Approximately 73,000 flight hours were accumulated on the components as of 1 January 1986. Three years of coupon tests on the components are presented with test results. A vertical fin had been struck by lightning and the results of its examination and tests are included
Static and dynamic helicopter airframe analysis with NASTRAN
The use of NASTRAN at Bell Helicopter Company for structural static and dynamic analysis of a helicopter airframe is described. Analysis of airframe internal loads, main rotor isolation systems, and airframe vibration is discussed. The use of each rigid format for these types of analysis is summarized. Suggested improvements to NASTRAN to increase its effectiveness in performing helicopter airframe analysis are given
Dark side illuminated: imaging of Toxoplasma gondii through the decades.
In the more than 100 years since its discovery, our knowledge of Toxoplasma biology has improved enormously. The evolution of molecular biology, immunology and genomics has had profound influences on our understanding of this ubiquitous bug. However, it could be argued that in science today the adage "seeing is believing" has never been truer. Images are highly influential and in the time since the first description of T. gondii, advances in microscopy and imaging technology have been and continue to be dramatic. In this review we recount the discovery of T. gondii and the contribution of imaging techniques to elucidating its life cycle, biology and the immune response of its host
Spectral absorption coefficients of carbon, nitrogen, and oxygen atoms
Spectral absorption coefficients of carbon, nitrogen, and oxygen atoms tabulated for use in radiant energy transfer calculation
Effect of shock precursor heating on radiative flux to blunt bodies
Effect of shock precursor heating on radiative flux to blunt bodie
Universal scaling behavior at the upper critical dimension of non-equilibrium continuous phase transitions
In this work we analyze the universal scaling functions and the critical
exponents at the upper critical dimension of a continuous phase transition. The
consideration of the universal scaling behavior yields a decisive check of the
value of the upper critical dimension. We apply our method to a non-equilibrium
continuous phase transition. But focusing on the equation of state of the phase
transition it is easy to extend our analysis to all equilibrium and
non-equilibrium phase transitions observed numerically or experimentally.Comment: 4 pages, 3 figure
Analytical infrared intensities for periodic systems with local basis sets
We report a method for the efficient evaluation of analytic infrared (IR)
intensities within generalized Kohn-Sham density functional theory using
Gaussian orbitals and periodic boundary conditions. A discretized form of the
Berry phase is used to evaluate a periodic dipole moment and its derivatives
with respect to in-phase nuclear coordinate displacements. Benchmark
calculations are presented for one-dimensional chains of water molecules and
poly(paraphenylenevinylene).Comment: 16 pages, 3 figures, 4 tables, submitted to Phys. Rev.
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