70,930 research outputs found
British literature since World War II : a selected bibliography of secondary sources with special reference to drama/theatre and narrative prose (period covered : mid-1940 to 2000)
British literature since world war II : a selected bibliography of secundary sources with special reference to drama/theatre and narrative prose (period covered : mid-1940 to 2000). Part I: Integrated alphabetical index. Part II: Specific bibliographies (as to author and subject
Structure determination of the reconstructed Au(110) surface
The LEED pattern of the Au(110) surface shows a (1 × 2) and also a (1× 3) superstructure. The (1 × 2) superstructure has been determined by comparison of LEED intensities with model calculations. The missing row model is the most probable model. A minimum of the averaged r-factor, , has been found for 15% contraction of the first layer spacing without atomic displacements in the second layer
Heat pipe thermal switch
A thermal switch for controlling the dissipation of heat between a body is described. The thermal switch is comprised of a flexible bellows defining an expansible vapor chamber for a working fluid located between an evaporation and condensation chamber. Inside the bellows is located a coiled retaining spring and four axial metal mesh wicks, two of which have their central portions located inside of the spring while the other two have their central portions located between the spring and the side wall of the bellows. The wicks are terminated and are attached to the inner surfaces of the outer end walls of evaporation and condensation chambers respectively located adjacent to the heat source and heat sink. The inner surfaces of the end walls furthermore include grooves to provide flow channels of the working fluid to and from the wick ends. The evaporation and condensation chambers are connected by turnbuckles and tension springs to provide a set point adjustment for setting the gap between an interface plate on the condensation chamber and the heat sink
Determination of domain distribution by analysis of LEED beam profiles
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Kinetics of ammonia penetrating into the sodalite units of sodium faujasites studied by nuclear magnetic resonance
Collision Rates in Charged Granular Gases
The dissipation rate due to inelastic collisions between equally charged,
insulating particles in a granular gas is calculated. It is equal to the known
dissipation rate for uncharged granular media multiplied by a Boltzmann-like
factor, that originates from Coulomb repulsion. Particle correlations lead to
an effective potential that replaces the bare Coulomb potential in the
Boltzmann factor. Collisional cooling in a granular gas proceeds with the known
t^-2 -law, until the kinetic energy of the grains becomes smaller than the
Coulomb barrier. Then the granular temperature approaches a time dependence
proportional to 1/ln(t). If the particles have different charges of equal sign,
the collision rate can always be lowered by redistributing the charge, until
all particles carry the same charge. Finally granular flow through a vertical
pipe is briefly discussed. All results are confirmed by computer simulations.Comment: Submitted to "Granular Matter
Supersonic wind tunnel nozzles: A selected, annotated bibliography to aid in the development of quiet wind tunnel technology
This bibliography, with abstracts, consists of 298 citations arranged in chronological order. The citations were selected to be helpful to persons engaged in the design and development of quiet (low disturbance) nozzles for modern supersonic wind tunnels. Author, subject, and corporate source indexes are included to assist with the location of specific information
Diffuse LEED intensities of disordered crystal surfaces : II. Multiple scattering on disordered overlayers
The diffraction of low energy electrons from disordered overlayers adsorbed on ordered substrates is treated theoretically by an extension of Beeby's multiple scattering method. A lattice gas model is assumed for the disordered adsorbate layer. Multiple scattering within a certain area around each atom — each atom of the overlayer and within the ordered substrate — is treated self-consistently, the remaining contributions to the total scattering amplitude being averaged. The theory can be used in the limiting cases of random distribution and of long range order within the adsorbate layer
Adaptive wall technology for minimization of wall interferences in transonic wind tunnels
Modern experimental techniques to improve free air simulations in transonic wind tunnels by use of adaptive wall technology are reviewed. Considered are the significant advantages of adaptive wall testing techniques with respect to wall interferences, Reynolds number, tunnel drive power, and flow quality. The application of these testing techniques relies on making the test section boundaries adjustable and using a rapid wall adjustment procedure. A historical overview shows how the disjointed development of these testing techniques, since 1938, is closely linked to available computer support. An overview of Adaptive Wall Test Section (AWTS) designs shows a preference for use of relatively simple designs with solid adaptive walls in 2- and 3-D testing. Operational aspects of AWTS's are discussed with regard to production type operation where adaptive wall adjustments need to be quick. Both 2- and 3-D data are presented to illustrate the quality of AWTS data over the transonic speed range. Adaptive wall technology is available for general use in 2-D testing, even in cryogenic wind tunnels. In 3-D testing, more refinement of the adaptive wall testing techniques is required before more widespread use can be planned
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