1,229 research outputs found
Method of electroforming a rocket chamber
A transpiration cooled rocket chamber is made by forming a porous metal wall on a suitably shaped mandrel. The porous wall may be made of sintered powdered metal, metal fibers sintered on the mandrel or wires woven onto the mandrel and then sintered to bond the interfaces of the wires. Intersecting annular and longitudinal ribs are then electroformed on the porous wall. An interchamber wall having orifices therein is then electroformed over the annular and longitudinal ribs. Parallel longitudinal ribs are then formed on the outside surface of the interchamber wall after which an annular jacket is electroformed over the parallel ribs to form distribution passages therewith. A feed manifold communicating with the distribution passages may be fabricated and welded to the rocket chamber or the feed manifold may be electroformed in place
Gravitational Waves and GRBs from Tidal Disruption of Stars in the Center of Galaxies
Recent measurements of the Chandra satellite have shown that a supermassive
black hole of is located in the Galactic
Center; it seems probable that, from other observations, this fact is common in
the majority of galaxies. On the other hand, GRB explosions are typical
phenomenon linked to the galactic dynamics. In the present paper we discuss the
possibility that GRBs are tidal disruption of stars by supermassive black holes
located in the center of galaxies. This conjecture can be tested by a
gravitational wave detector of the class of AURIGA.Comment: 4 pages, 2 figures talk at Gamma Ray Burst Symposium - Santa Fe, New
Mexico (USA) September 8-12, 2003. There were added four new references and
the entrances of the two figures were written in a more clear wa
Joining porous components to solid metal structures
Process for joining porous metal material to solid metal structure without cracking or blockage of porous component is described. Procedures of electron beam welding and electroforming are discussed. Illustration of microstructure resulting from process is included
Electrical gas heater with large flow range capability
Auxiliary heat transfer device in form to tightly-wound helical tube was incorporated into conventional heater design to provide hydrogen heater with turn-down ratio greater than 100. Device greatly increases low flow rate capacity of heater by providing maximum heat-transfer area for low mass flows
Heat exchanger and method of making
A heat exchange of increased effectiveness is disclosed. A porous metal matrix is disposed in a metal chamber or between walls through which a heat-transfer fluid is directed. The porous metal matrix has internal bonds and is bonded to the chamber in order to remove all thermal contact resistance within the composite structure. Utilization of the invention in a rocket chamber is disclosed as a specific use. Also disclosed is a method of constructing the heat exchanger
Heat exchanger and method of making
A heat exchanger of increased effectiveness is disclosed. A porous metal matrix is disposed in a metal chamber or between walls through which a heat-transfer fluid is directed. The porous metal matrix has internal bonds and is bonded to the chamber in order to remove all thermal contact resistance within the composite structure. Utilization of the invention in a rocket chamber is disclosed as a specific use. Also disclosed is a method of constructing the heat exchanger
Thermal conductivity and electrical resistivity of porous materials
Process for determining thermal conductivity and electrical resistivity of porous materials is described. Characteristics of materials are identified and used in development of mathematical models. Limitations of method are examined
Uniform high irradiance source
New 50 Kw xenon short arc lamp mounted within elliptical collector provides irradiance levels up to 4.4 x 10 to the 7th power watts/sq m with non-uniformity ratio of 3.30. Energy mixer or light pipe between lamp source and target improves non-uniformity to required ratio
Three-dimensional structure of the flow inside the left ventricle of the human heart
The laboratory models of the human heart left ventricle developed in the last
decades gave a valuable contribution to the comprehension of the role of the
fluid dynamics in the cardiac function and to support the interpretation of the
data obtained in vivo. Nevertheless, some questions are still open and new ones
stem from the continuous improvements in the diagnostic imaging techniques.
Many of these unresolved issues are related to the three-dimensional structure
of the left-ventricular flow during the cardiac cycle. In this paper we
investigated in detail this aspect using a laboratory model. The ventricle was
simulated by a flexible sack varying its volume in time according to a
physiologically shaped law. Velocities measured during several cycles on series
of parallel planes, taken from two orthogonal points of view, were combined
together in order to reconstruct the phase averaged, three-dimensional velocity
field. During the diastole, three main steps are recognized in the evolution of
the vortical structures: i) straight propagation in the direction of the long
axis of a vortex-ring originated from the mitral orifice; ii) asymmetric
development of the vortex-ring on an inclined plane; iii) single vortex
formation. The analysis of three-dimensional data gives the experimental
evidence of the reorganization of the flow in a single vortex persisting until
the end of the diastole. This flow pattern seems to optimize the cardiac
function since it directs velocity towards the aortic valve just before the
systole and minimizes the fraction of blood residing within the ventricle for
more cycles
Turbulence, heat-transfer, and boundary layer measurements in a conical nozzle with a controlled inlet velocity profile
Turbulence, heat transfer, and boundary layer measurements in conical nozzl
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