112,117 research outputs found
Fabrication process of a high temperature polymer matrix engine duct
The process that was used in the molding of an advanced composite outer by-pass duct planned for the F404 engine is discussed. This duct was developed as a potential replacement for the existing titanium duct in order to reduce both the weight and cost of the duct. The composite duct is now going into the manufacturing technology portion of the program. The duct is fabricated using graphite cloth impregnated with the PMR-15 matrix system
Measurements of the free-bound and free-free continua of nitrogen, oxygen and air
Photometric measurement of radiation in high temperature ai
Dispersion strengthening in vanadium microalloyed steels processed by simulated thin slab casting and direct charging. Part 2 - chemical characterisation of dispersion strengthening precipitates
The composition of the sub-15 nm particles in six related vanadium high strength low alloy steels, made by simulated thin slab direct charged casting, has been determined using electron energy loss spectroscopy (EELS). Such particles are considered to be responsible for dispersion hardening. For the first time, particles down to 4 nm in size have had their composition fully determined. In all the steels, the particles were nitrogen and vanadium rich and possibly slightly sub-stoichiometric carbonitrides. Equilibrium thermodynamics predicted much higher carbon to metal atomic ratios than observed in all cases so that kinetics and mechanical deformation clearly control the precipitation process. Thus it is important to formulate the steel with this in mind
Connecting physical resonant amplitudes and lattice QCD
We present a determination of the isovector, -wave scattering
phase shift obtained by extrapolating recent lattice QCD results from the
Hadron Spectrum Collaboration using MeV. The finite volume spectra
are described using extensions of L\"uscher's method to determine the infinite
volume Unitarized Chiral Perturbation Theory scattering amplitude. We exploit
the pion mass dependence of this effective theory to obtain the scattering
amplitude at MeV. The scattering phase shift is found to be in
good agreement with experiment up to center of mass energies of 1.2 GeV. The
analytic continuation of the scattering amplitude to the complex plane yields a
-resonance pole at .
The techniques presented illustrate a possible pathway towards connecting
lattice QCD observables of few-body, strongly interacting systems to
experimentally accessible quantities.Comment: 8 pages, 6 figures, equivalent to published version, added two
appendices and a figur
System design study for an optimal remote oculometer for use in operational aircraft
System design of optimal remote oculometer for use in operational aircraf
Compressed gas handbook
Handbook includes thermodynamic and related fluid flow data required to analyze high pressure compressible and incompressible fluid systems. Some theory and applications include thermodynamic fundamentals, gas behavior, adiabatic and isentropic flow, shock waves, flow measurement, and adiabatic and isothermal friction flow in pipes
Analysis of the physical atomic forces between noble gas atoms, alkali ions and halogen ions
The physical forces between atoms and molecules are important in a number of processes of practical importance, including line broadening in radiative processes, gas and crystal properties, adhesion, and thin films. The components of the physical forces between noble gas atoms, alkali ions, and halogen ions are analyzed and a data base for the dispersion forces is developed from the literature based on evaluations with the harmonic oscillator dispersion model for higher order coefficients. The Zener model of the repulsive core is used in the context of the recent asymptotic wave functions of Handler and Smith; and an effective ionization potential within the Handler and Smith wave functions is defined to analyze the two body potential data of Waldman and Gordon, the alkali-halide molecular data, and the noble gas crystal and salt crystal data. A satisfactory global fit to this molecular and crystal data is then reproduced by the model to within several percent. Surface potentials are evaluated for noble gas atoms on noble gas and salt crystal surfaces with surface tension neglected. Within this context, the noble gas surface potentials on noble gas and salt crystals are considered to be accurate to within several percent
Electron Emission from Diamondoids: A Diffusion Quantum Monte Carlo Study
We present density-functional theory (DFT) and quantum Monte Carlo (QMC)
calculations designed to resolve experimental and theoretical controversies
over the optical properties of H-terminated C nanoparticles (diamondoids). The
QMC results follow the trends of well-converged plane-wave DFT calculations for
the size dependence of the optical gap, but they predict gaps that are 1-2 eV
higher. They confirm that quantum confinement effects disappear in diamondoids
larger than 1 nm, which have gaps below that of bulk diamond. Our QMC
calculations predict a small exciton binding energy and a negative electron
affinity (NEA) for diamondoids up to 1 nm, resulting from the delocalized
nature of the lowest unoccupied molecular orbital. The NEA suggests a range of
possible applications of diamondoids as low-voltage electron emitters
Characterization of nickel-cadmium electrodes final report, 1 jul. 1963 - 31 dec. 1964
Characterization of electrodes in nickel-cadmium spacecraft batteries prior to and after cyclic testin
Symmetry Analysis of Multiferroic Co_3TeO_6
A phenomenological explanation of the magnetoelectric behavior of Co_3TeO_6
is developed. We explain the second harmonic generation data and the magnetic
field induced spontaneous polarization in the magnetically ordered phase below
20K.Comment: Phys rev B Rapids, to appea
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