High speed video and streak camera imaging are used to measure peak pressures for explosions of spherical charges of the high explosive C‐4 (92 % trimethylenetrinitramine, C3H6N6O6). The technique measures the velocity of the air shock produced by the detonation of the explosive charges, converts this velocity to a Mach number, and uses the Mach number to determine a peak shock pressure. Peak pressure measurements are reported from a few millimeters to approximately one meter from the charge surface. Optical peak pressure measurements are compared to peak pressures measured using piezoelectric pressure transducers, and to peak pressure measurements estimated using the blast computer code CONWEP. A discussion of accuracy of peak pressures determined optically is provided.
This work describes chemical imaging of BO2 formed during ballistic initiation of 1 : 1 by weight powder‐mixtures of boron (B) and potassium nitrate (KNO3) contained within a polyethylene spherical projectile (25 mm diameter). Initiation was achieved by impact of the gas‐gun‐launched B/KNO3‐filled projectile with an anvil in a windowed, air‐filled chamber. To monitor the subsequent chemical reaction, a two‐camera, optically‐filtered method to map discrete chemical emission from the BO2 molecule was used. This technique distinguishes incandescence of hot particles produced during the event from discrete chemical emission by BO2 near a wavelength of 546 nanometers (nm). The dependence of delay in BO2 chemical emission (that exceeded particle incandescence) with impact velocity was investigated and chemical emission movies which ratio the intensity of discrete to thermal emission are discussed. Emission spectra (300–1000 nm wavelength) were recorded during the impact event, and used to determine a grey‐body temperature of the hot particles during the time when BO2 emission was most intense.
Abstract. Reactive flow models are desired for new explosive formulations early in the development stage. Traditionally, these models are parameterized by carefully-controlled 1-D shock experiments, including gas-gun testing with embedded gauges and wedge testing with explosive plane wave lenses (PWL). These experiments are easy to interpret due to their 1-D nature, but are expensive to perform and cannot be performed at all explosive test facilities. This work investigates alternative methods to probe shock-initiation behavior of new explosives using widely-available pentolite gap test donors and simple time-of-arrival type diagnostics. These experiments can be performed at a low cost at most explosives testing facilities. This allows experimental data to parameterize reactive flow models to be collected much earlier in the development of an explosive formulation. However, the fundamentally 2-D nature of these tests may increase the modeling burden in parameterizing these models and reduce general applicability. Several variations of the so-called modified gap test were investigated and evaluated for suitability as an alternative to established 1-D gas gun and PWL techniques. At least partial agreement with 1-D test methods was observed for the explosives tested, and future work is planned to scope the applicability and limitations of these experimental techniques.
Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 5f. WORK UNIT NUMBER AXEUMM experiments were conducted to investigate the presence/absence of jetting at the charge surface of detonating energetic materials due to the detonator employed. Experiments are conducted using gram-range spherical charges in the blast chamber at the U.S. Army Research Laboratory's Detonation Science Facility. Early-time high-speed images of the detonation wave's breakout and air shock wave's early-time expansion are captured using a high-speed intensified camera. Explosively driven air shock waves are qualitatively analyzed throughout their early-time expansion. Captured images are shown to exhibit a nearly spherical air shock wave throughout early-time expansion without the presence of jetting due to the detonator. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER SPONSOR/MONITOR'S ACRONYM(S) 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) SPONSOR/MONITOR'S REPORT NUMBER(S)laboratory-scale, detonator, jetting effects, high-speed UU 14
The WAIS was administered to 100 black and 100 white male Air Force basic trainees. t tests showed that the white group scored significantly higher on Verbal IQ, Performance IQ, and Full Scale IQ and on all subtests except Digit Span and Digit Symbol. Findings were discussed in terms of cultural opportunity and heritability.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.