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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Supernova explosions.

The recent history of theoretical investigations of the supernova mechanism is considered, giving attention also to a number of nuclear physical problems which have yet to be solved in connection with the thermonuclear detonation. A variety of different processes of nucleo-synthesis are expected to occur in association with the supernova explosions. Aspects of the chemical evolution of the galaxy are discussed including the cosmic ray production of lithium, beryllium, and boron in the interstellar medium. Various hypotheses to account for the very large amount of light that comes from a supernova explosion are also examined.

Cameron, A. G. W.↗
NASA NTRS1973

Experiments in gasdynamics of explosions.

Various topics concerning recent accomplishments in experimental studies of gasdynamics of explosions are reviewed. Detonations, shocks, and blast waves form these topics. The most important feature of current studies is the particular attention paid to transient processes and the concomitant progress made in the development of novel experimental means for the study of such processes. The most exciting prospects for the future are associated with possibilities of exploiting knowledge of explosion phenomena for the development of such interesting devices as the gasdynamic laser and the apparatus based on the use of lasers to achieve controlled thermonuclear reaction.

Oppenheim, A. K.↗
NASA NTRS1973

Photographic laboratory studies of explosions.

Description of a series of cinematographic studies of explosions made with a high-speed rotating-mirror streak camera which uses a high-frequency stroboscopic ruby laser as the light source. The results obtained mainly concern explosions initiated by focused laser irradiation from a pulsed neodymium laser in a detonating gas consisting essentially of an equimolar mixture of acetylene and oxygen at an initial pressure of 100 torr at room temperature. Among the most significant observations were observations of a spherical blast wave preceded by a Chapman-Jouguet detonation which is stabilized immediately after initiation, the merging of a spherical flame with a shock front of the blast wave in which the flame is propagating, the division of a spherical detonation front into a shock wave and flame, and the generation of shock waves by a network of spherical flames.

Kamel, M. M.↗
NASA NTRS1974

Apparatus for monitoring linear explosive performance

Techniques provide performance monitoring standard for acceptance, lot qualification, and comparison testing of devices. Exhibit high degree of simplicity, accuracy, and reproducibility. Apparatus simultaneously measures explosive pressure stimulus energy, explosive cutting, or rupturing, ability, and detonation propagation rate.

Bement, L. J.↗
NASA NTRS1975

Explosive welding technique for joining aluminum and steel tubes

Silver sheet is wrapped around aluminum portion of joint. Mylar powder box is wrapped over silver sheet. Explosion welds silver to aluminum. Stainless-steel tube is placed over silver-aluminum interface. Mylar powder box, covered with Mylar tape, is wrapped around steel member. Explosion welds steel to silver-aluminum interface.

Wakefield, M. E.↗
NASA NTRS1973

A laser initiated explosive device system

A laser initiated explosive system has been developed which can simultaneously initiate multiple explosive devices. Advantages of this system over electrically initiated devices (EED's) are increased safety and reliability, simplicity of laser initiated devices, and increased weight efficiency. The system design with test data are presented and a comparison between laser initiation and electrical initiation is discussed.

Yang, L. C.↗
NASA NTRS1973

Consistency of cosmic-ray source abundances with explosive nucleosynthesis

Certain results regarding the ratio of cosmic-ray sources (CRS) and Solar System abundances are the same as those obtained from explosive nucleosynthesis. Such a model is consistent with the fact that in the Solar System Mg, Si, and Fe are believed to be produced by explosive nucleosynthesis, whereas C and O are mainly products of other processes. The model considered explains the carbon-to-oxygen ratio in the cosmic rays.

Kozlovsky, B.↗
NASA NTRS1974

Method of making an explosively welded scarf joint

A method is presented for obtaining a bond joint between thin metal members without the addition of a bonding agent. The method yields bond strengths comparable to the parent metal. The method comprises overlapping the materials at the edges and bonding them by explosive welding while also making use of the explosive force to shape the materials into an essentially planar configuration.

Bement, L. J.↗
NASA NTRS1977

Estimates of explosive yield

Explosive yield as a function of propellant type and accident conditions was discussed along with the characteristics of propellant explosions. Three types of fuel-hypergolic, liquid oxygen-hydrocarbon, and liquid oxygen-liquid-hydrogen were considered. Data are also given on three modes (failure modes) of mixing: confinement by missile, confinement by ground surface, and high velocity impact.

Source record↗
NASA NTRS1975

The development of spacecraft explosives for the Lyndon B. Johnson Space Center

Several heat resistant secondary explosives suitable for use in spacecraft hardware were characterized and tested in order to select a prime candidate for further study. The design goal criterion was that no significant degradation of the explosive takes place after exposure to 315 C. The final selection was made from the following candidates: PYX (2,6-bis (picrylamino)-3,5-dinitropyridine), ONT (octanitro-m-terphenyl), and TPT (2,4,6 tripicryl-s-triazine), following performance tests in detonating cords. TPT was the final selection and was further characterized and evaluated in order to obtain data for a procurement specification.

Source record↗
NASA NTRS1977

Evaluating of NASA-Langley Research Center explosion seam welding

An explosion bonding technique to meet current fabrication requirements was demonstrated. A test program was conducted on explosion bonded joints, compared to fusion joints in 6061-T6 aluminum. The comparison was made in required fixtures, non-destructive testing, static strength and fatigue strength.

Otto, H. E.↗
NASA NTRS1978

A test of the comet hypothesis of the Tunguska Meteor Fall - Nature of the meteor 'thermal' explosion paradox

The hypothesis that a comet was responsible for the Tunguska Meteor Fall is rejected because the hypothesis does not seem to account for the intense terminal spherical shock. A porous meteoroid model is proposed, and an analysis indicates that an entity of this type might produce an aerodynamic heat flux large enough to account for the terminal meteor explosion. It is suggested that the presence of olivine and of highly irregular macrostructure in meteors might indicate the presence of some porosity. For a highly porous meteoroid, it is postulated that during entry into the atmosphere the aerodynamic heat transfer at its external or pore walls would become so intensified as to cause either complete ablation with popping or a solid-liquid-vapor phase transition accompanied by an explosion.

Liu, V. C.↗
NASA NTRS1978

Explosive tearing mode reconnection in the magnetospheric tail

A speculative model for the nonlinear phase of the collisionless tearing instability is developed for the case of a single long wavelength tearing mode. Using an energy principle formalism, we find that the nonlinear growth rate is linearly proportional to the mode amplitude. Hence in the nonlinear phase, the tearing mode grows explosively in time, and saturates when the width of the magnetic islands become comparable to the thickness of the current sheet. For typical plasma sheet parameters, the explosive phase lasts 5-10 minutes, and develops cross-tail emf's of several 100 KV.

Galeev, A. A.↗
NASA NTRS1979

Estimating effects of accidental propellant explosions

Workbook assesses magnitudes and effects of blasts and fragments from ground system explosions. It provides designer and safety engineer with rapid methods for predicting damage and hazards from explosions of liquid-propellant and compressed-gas vessels used in ground storage, transport, and handling.

Ordin, P. M.↗
NASA NTRS1979

Confined explosive joining of tubes

Technique uses explosive ribbon to join and seal tubes hermetically while totally confining explosive products, such as smoke, light, and sound. Only click is audible. Process yields joints of the same strengths as parent metal.

Bement, L. J.↗
NASA NTRS1978

Workbook for estimating effects of accidental explosions in propellant ground handling and transport systems

A workbook is presented to supplement an earlier NASA publication, which was intended to provide the designer and safety engineer with rapid methods for predicting damage and hazards from explosions of liquid propellant and compressed gas vessels used in ground storage, transport and handling. Information is presented in the form of graphs and tables to allow easy calculation, using only desk or handheld calculators. Topics covered in various chapters are: (1) estimates of explosive yield; (2) characteristics of pressure waves; (3) effects of pressure waves; (4) characteristics of fragments; and (5) effects of fragments and related topics.

Baker, W. E.↗
NASA NTRS1979

Numerical study of an explosion in a non-homogeneous medium with and without magnetic fields

A version of the two step Lax-Wendroff difference method with second order accuracy is used to seek solutions of the unsteady magnetohydrodynamic (MHD) equations for the study of an explosion in a non-homogeneous medium with and without magnetic fields. The explosion is initiated by introducing a finite amount of energy in a small volume of gas which leads to an instantaneous increase of gas temperature. Two types of magnetic field configurations (i.e. open and closed) are considered to illustrate the dependence and differences of magnetic and a non-magnetic flow motion. Numerical results show the strong dependence of induced MHD flow field on the magnetic field configuration and strength. The development and decay of the fast and slow MHD shock waves, as well as the ordinary gasdynamic shock waves, are also represented well by the present computer simulations. In conclusion, we have demonstrated that the numerical scheme we have used is a reliable one for studying 2-dimensional MHD problems in non-homogeneous medium.

Han, S. M.↗
NASA NTRS1979

Evidence for explosive volcanic density currents on certain Martian volcanoes

The morphologies of certain of the smaller Martian volcanoes are discussed as possible results of explosive volcanic density currents. An examination of newly-photographed flank and caldera features of the Martian volcanoes Ceraunius Tholus, Uranius Tholus, Uranius Patera and Hecates Tholus, including steep slope angles, Krakatoa-type caldera morphologies, erosional features (radial channels and anastamosing gullies) and constructional features (blanketed flanks and possible lava deltas) reveals their similarity to terrestrial cones and composite volcanoes such as Barcena Volcano. Crater age data from the surface of Martian domes and shields indicates that such explosive activity occurred more frequently early in Martian geologic history, consistent with the view that the volcanic density currents were base surges rather than nuees ardentes, with the melting of permafrost supplying the water required in base surge generation.

Reimers, C. E.↗