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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 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
NASA NTRS1967

Thermal explosion analyses

Existence of approximate solution for critical slab hot-spot size for entire range of practical thermal explosion problems

EXPLOSION↗
NASA NTRS1967

Explosive projection of metal

Effects of geometrical variations in shape of explosive device on direction of projection of metal casing parts in guided missile warheads

WARHEAD↗
DOE OSTI2016

Fire and Explosion Hazards Expected in a Laboratory

Scientists at universities across Iraq are actively working to report actual incidents and accidents occurring in their laboratories, as well as structural improvements made to improve safety and security, to raise awareness and encourage openness, leading to widespread adoption of robust Chemical Safety and Security (CSS) practices. This manuscript is the fifth in a series of five case studies describing laboratory incidents, accidents, and laboratory improvements. In this study, we summarize unsafe practices involving the improper installation of a Gas Chromatograph (GC) at an Iraqi university which, if not corrected, could have resulted in a dangerous fire and explosion. We summarize the identified infractions and highlight lessons learned. Here, by openly sharing the experiences at the university involved, we hope to minimize the possibility of another researcher being injured due to similarly unsafe practices in the future.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Ultra-Trace and Vapor Detection of Explosives and Narcotics Finalist for R&D 100 Award

An instrument more sensitive than a canine’s nose identifies explosives and narcotics vapors in real time and at levels previously undetectable than any other sampling technology. The instrument is one among five PNNL-developed technologies in the running for an R&D 100 Award. Known as VP-IDENT, the tool coupled with a mass spectrometer, is ideal for aviation security, cargo screening, and broader counter-terrorism and national security activities where discovering dangerous substances is of utmost importance. Listen as researcher Robert Ewing explains.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2019

Chemical explosive mode analysis of lean blowout in a gas turbine combustor

In this study, stabilization and lean blowout (LBO) mechanisms in a gas turbine combustor are numerically studied based on large eddy simulation (LES) data and the chemical explosive mode analysis (CEMA). Three CEMA-based local combustion modes, that is, auto-ignition, diffusion-assisted ignition, and extinction, are employed to quantify interactions between local diffusion and chemical processes in complex turbulent fields. The capability of CEMA-based local modes in extinction detection is first demonstrated in a one-dimensional non-premixed flamelet undergoing transient extinction. Flame structure and dynamics in the gas turbine combustor are then examined in detail using CEMA and the local combustion modes for both the stably burning and lean blowout conditions. Local structure comprised of all the three modes are identified, and each mode is found to play an important role in determining the overall burning rate. The heat release rate attributed to each local mode remains nearly constant at the stably burning condition. In contrast, the flame during LBO shows a two-stage extinction behavior: at the initial stage, the extinction mode is largely enhanced and becomes dominant over the assisted-ignition model; at the second stage, all three modes are suppressed, signifying global extinction. It is therefore suggested that the excessive local extinction mode, due to an increased amount of heat and radical losses through diffusion, finally leads to lean flame blowout.

chemical explosive mode↗
DOE OSTI2023

High fidelity ground deposition measurement with robots after explosive radiological dispersion

A team of scientists from the Remote Sensing Laboratory at Joint Base Andrews, Maryland, has assembled a remote-controlled robot to field a few sodium iodide scintillators of different size and shape 18″ above ground for measurement of ground deposition of gamma-emitting particles after an explosion of a radiological dispersal device. This system uses a high-precision differential GPS device with submeter accuracy for radiation mapping. The system is most useful in characterizing large-area contamination and detecting gamma radioactivity in invisible, submicron particulate debris deposited on the ground at surface level or embedded in subsurface up to 3″ deep. The system was assembled as part of a larger effort to integrate advanced radiological detection devices into autonomous or remote-controlled robotic systems to eliminate or minimize the need for emergency responders to enter areas that pose significant health and safety risks to humans following a major radiological incident or accident. Research into autonomous algorithms is required to develop automated robotic systems for radiological survey and characterization activities in highly contaminated areas. The scope of this project also includes developing communications pathways and supporting infrastructure capabilities for different types of robotic technologies. The expected result is an advanced autonomous robotic system with integrated radiation detection electronics that allows emergency response personnel to view data remotely and in real time for radiological emergency response and consequence management purposes.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

Acoustic Explosion Data Archive for Machine Learning

The prompt detection of explosions is a key element of the nuclear non-proliferation mission. With traditional sensors being limited in number and scale, smartphones as compact and economical multi-modal sensors are gaining traction and are being deployed. To address the flood of heterogeneous smartphone data, our team proposes a feature extraction using standardized constant-Q frequency bands across acoustic, barometric, and accelerometer data. The work in this presentation contains data collected at Idaho National Laboratory during planned detonations.

46 - INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AN↗
DOE OSTI2022

Decomposition of Irganox 1010 in plastic bonded explosives

Abstract Degradation pathways of Irganox 1010 in aged plastic bonded explosive (PBX) 9501 were investigated using ultrahigh performance liquid chromatography coupled to quadrupole time of flight mass spectrometry (UHPLC‐QTOF). Using a targeted approach, a total of 44 Irganox 1010 decomposition products were discovered. These decomposition products were formed through hydrolysis, scission, and/or oxidation of Irganox 1010. The hydrolytic decomposition of Irganox is a straightforward process resulting in the cleavage of the ester group(s) while oxidation and scission are more complicated and can happen at multiple locations on the Irganox 1010 molecule. Moreover, due to the symmetric nature of Irganox 1010, multiple decomposition reactions can occur. Indeed some decomposition products exhibited hydrolysis, oxidation, and scission. In order to probe any trends in the aged PBX 9501 samples, principal component analysis (PCA) was implemented. The greatest chemical differences between the aged PBX samples was hydrolysis of the ester functional groups on Irganox 1010. Despite the negative connotations of hydrolysis, the Irganox 1010 decomposition products are still able to function as a radical scavenger in PBX 9501 as intended.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗