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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 1,675 records · Page 93
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Isotropic neutrino flux from supernova explosions in the universe

Neutrinos of all types are emitted from the gravitational collapse of massive star cores, and have been amassed in the Universe throughout the history of evolution of galaxies. The isotropic and stable flux of these neutrinos is a source of information on the spectra of neutrinos from individual supernovae and on their redshift distribution. The prospects for detecting the isotropic neutrino flux with the existing and upcoming experimental facilities and the current upper limits are discussed in this paper.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Determining fast-S and slow-S propagation directions with SV-P data produced by buried explosives and recorded with vertical geophones

We have evaluated the concept of practicing S-wave reflection seismology with legacy 3D seismic data generated by a P-wave source and recorded with only vertical geophones. This type of S-wave imaging is based on the principle that seismic P-wave sources not only produce a downgoing illuminating P wavefield, but they also simultaneously produce a downgoing illuminating SV wavefield that, in almost all cases, is suitable for S-wave reflection imaging. The S-mode used in this study is the SV-P, or converted-P, mode. This mode involves a downgoing illuminating SV wavefield and an upgoing reflected P-mode that is recorded by vertical geophones. In flat-layered stratigraphy, the lengths of the SV and P raypaths in SV-P imaging are identical to the lengths of the SV and P raypaths in P-SV imaging with P-sources and 3C geophones. P-SV imaging of deep rocks has been practiced for more than two decades; SV-P imaging is a new concept. SV-P data should provide the same options for investigating deep rocks as do P-SV data. We have determined one of the equivalences between SV-P data extracted from vertical-geophone data and P-SV data extracted from horizontal geophones: that both modes react to azimuth-dependent variations in the S velocity in anisotropic rocks. Azimuthal variations in the SV-P traveltime can be used to define the polarization direction of the fast-S-wave mode, which is also the azimuth of the maximum horizontal stress (SHmax). Our investigation demonstrates a noninvasive method for monitoring changes in the SHmax azimuth across a CO 2 storage reservoir, or any targeted porous rock, as fluids are cycled into, and then out of, that rock’s pore space.

Geochemistry & Geophysics↗
DOE OSTI2019

Locating Surface Explosions by Combining Seismic and Infrasound Data

An outline of a Bayesian source location framework for using seismic and acoustic observations is developed and tested on synthetic and real data. Seismic and acoustic phenomena are both commonly used in detection and location of a variety of natural or man–made events, such as volcanic eruptions, quarry blasts, and military exercises. Typically, seismic and acoustic observations have been utilized independently of each other. Here, we outline a Bayesian formulation for combining the two observations in a single estimate of the location and origin time. Using realistic estimates of uncertainty, we subsequently explore how combining the different observation types can benefit event location at local to near–regional distances. We apply the method to synthetic data and to real observations from a mining blast in Bingham Mine in Utah. Our findings suggest that, for relatively sparse or azimuthally limited observations, the relative strengths of the two different phenomenologies enable more precise joint–event localization than either seismic or infrasonic measurements alone.

58 GEOSCIENCES↗
DOE OSTI2013

Constituent properties, process, and formulation effects contributing to functional characteristics in pharmaceutical and explosive composites [Slides]

Crystal properties and defects contribute substantially to basic properties. Dip-coated films display a number of properties which are expected to be present in wet agglomeration / real formulation. Nanoindentation provides more detailed information about static dislocations and a useful simulation of real deformation processes during formulation of pressed composites. Continuum measurements are limited in what can be mechanistically determined, but we are on the verge of breakthroughs in dynamic in situ experiments!

36 MATERIALS SCIENCE↗
DOE OSTI2013

EDS V26 Containment Vessel Explosive Qualification Test Report

The objective of the test was to qualify the vessel for its intended use by subjecting it to a 1.25 times overtest. The criteria for success are that the measured strains do not exceed the calculated strains from the vessel analysis, there is no significant additional plastic strain on subsequent tests at the rated design load (shakedown), and there is no significant damage to the vessel and attached hardware that affect form, fit, or function. Testing of the V25 Vessel in 2011 established a precedent for testing V26 [2]. As with V25, two tests were performed to satisfy this objective. The first test used 9 pounds of Composition C-4 (11.25 lbs. TNT-equivalent), which is 125 percent of the design basis load. The second test used 7.2 pounds of Composition C-4 (9 lbs. TNT-equivalent) which is 100 percent of the design basis load. The first test provided the required overtest while the second test served to demonstrate shakedown and the absence of additional plastic deformation. Unlike the V25 vessel, which was mounted in a shipping cradle during testing, the V26 vessel was mounted on the EDS P2U3 trailer prior to testing. Visual inspections of the EDS vessel, surroundings, and diagnostics were completed before and after each test event. This visual inspection included analyzing the seals, fittings, and interior surfaces of the EDS vessel and documenting any abnormalities or damages. Photographs were used to visually document vessel conditions and findings before and after each test event.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Ranchero Armature Test LA-43-CT-2: PBXN-110 Explosive with no smoothing layer. Lower Slobovia, 6/13/13

This test, documented as LA-43-CT-2, was performed to verify calculations which indicate that the smoothing layer employed for Ranchero Armatures is not required when the slapper point spacing is 18 mm (“On the efficacy of an acrylic layer in the Ranchero armature,” Bob Watt, published in “Ranchero Status Report” LA-14463). [Naming this test –CT-2 acknowledges the previous test performed during 1/11 as the initial test in the series, and we will refer to that test as LA-43-CT-1 in the future.] In addition, higher velocity is achieved when the volume occupied by the smoother is replaced by HE. Two framing cameras were used on the shot, and a 20 point PDV array was fielded to ascertain armature performance in specific conditions. The conclusions are that the armature is smooth enough, and the terminal velocity is increased from ~3.1 mm/μs to ~3.3 mm/μs. The armature tested had casting voids in the HE that were observed in pre-test inspections, and were expected to cause ruptures. (See Appendix 3 of the Ranchero Status Report.) Such “blowouts” were observed in all three locations identified in pre-shot inspection. In addition, ruptures occurred in locations having no pre-shot indication of a problem. These unpredicted blowouts have a difference in appearance from those typically seen. Further visual examination of the inspection radiographs do not reveal the cause, and that is a serious concern for future efforts with such castings. A path forward will include attempting to digitize the inspection x-rays for the charge tested, to see if the cause of the “new” ruptures can be found via computer enhancement. In addition, there are two additional armatures from the same casting lot, and these might also be tested to see if there is some problem with the HE or the armature material in this batch. For now, this plan is on hold, pending the outcome of tests and cost estimates related to using PBX-9501 in place of the PBXN-110. Casting issues would be eliminated in such configurations.

42 ENGINEERING↗
DOE OSTI2014

Explosive Products EOS: Adjustment for detonation speed and energy release

Propagating detonation waves exhibit a curvature effect in which the detonation speed decreases with increasing front curvature. The curvature effect is due to the width of the wave profile. Numerically, the wave profile depends on resolution. With coarse resolution, the wave width is too large and results in a curvature effect that is too large. Consequently, the detonation speed decreases as the cell size is increased. We propose a modification to the products equation of state (EOS) to compensate for the effect of numerical resolution; i.e., to increase the CJ pressure in order that a simulation propagates a detonation wave with a speed that is on average correct. The EOS modification also adjusts the release isentrope to correct the energy release.

97 MATHEMATICS AND COMPUTING↗