Steven Son

Independent Researcher

Aluminized ammonium perchlorate composite propellants can form large molten agglomerated particles that may result in poor combustion performance, slag accumulation, and increased two-phase flow losses. Quantifying agglomerate size distributions are needed to gain an understanding of agglomeration dynamics and ultimately design new propellants for...

We have employed, to the best of our knowledge, a novel excitation scheme to perform the first high-repetition-rate planar laser-induced fluorescence (PLIF) measurements of a CN radical in combustion. The third harmonic of a Nd:YVO4 laser at 355 nm due to its relatively large linewidth overlaps with several R branch transitions in a CN ground elect...

Composite propellants based on the solid nitrate ester 2,3-hydroxymethyl-2,3-dinitro-1,4-butanediol tetranitrate (SMX) were theoretically and experimentally examined and compared to formulations based on ammonium perchlorate (AP). Thermochemical equilibrium calculations show that aluminized SMX-based formulations can achieve theoretical sea level s...

Double base propellants composed of nitrocellulose (NC) and nitroglycerine (NG) are widely used. However, the inclusion of liquid NG presents both stability and performance problems: the NG may migrate from the propellant in storage, and it softens the propellant at high inclusion levels. In this work, the novel nitrate ester 1,4-dinitrato-2,3-dini...

Replacement reactive systems for the tungsten delay composition (W/BaCrO4/KClO4/diatomaceous earth) are needed due to recent concerns over the toxicity of hexavalent chromium and perchlorates. Systems based on condensed phase reactions, that are typically used in combustion synthesis (e.g., Ti/C or Ni/Al) are of interest as replacements due to thei...

In solid propellants, aluminum is widely used to improve performance, yet theoretical specific impulse is still not achieved largely because of two-phase flow losses. Losses could be reduced if aluminum particles quickly ignited, more gaseous products were produced and if upon combustion, aluminum particle breakup occurred. To explore this, tailore...

Imaging dynamic multiphase combusting events is challenging. Conventional techniques can image only a single plane of an event, capturing limited details. Here, we report on a three-dimensional, time-resolved, OH planar laser-induced fluorescence (3D OH PLIF) technique that was developed to measure the relative OH concentration in multiphase combus...

Microwave frequency electromagnetic properties are critical for understanding and predicting the heating and ignition behavior of explosives subjected to microwave irradiation. In this work we report relative complex permittivity measurements in the X-band (8–12 GHz) for 13 neat explosives measured by the circular cavity technique. This data set wa...

The influence of low levels of lattice doping in silicon on the combustion and reaction kinetics of silicon based reactives was investigated. Doped silicon powders were produced by ball milling intrinsic, As-, and B-doped silicon wafers. After morphological and physical characterization of the doped silicon powders, energetic composites consisting...

High speed (5 kHz) planar laser-induced fluorescence (PLIF) and high resolution imaging are used to probe the flame structure and to image coarse ammonium perchlorate (AP) particles on the surface of deflagrating bimodal composite propellants formulated with various binders. Three binder systems are examined: hydroxyl-terminated polybutadiene (HTPB...

Combustion simulations at the micro and meso-scales are coupled to give a more theoretically based and accurate description of AP (ammonium perchlorate)/HTPB (hydroxyl-terminated polybutadiene) composite propellant combustion. One and two-dimensional micro-scale combustion models of AP and AP/HTPB, which include detailed kinetics and species transp...

The liners of US military helmets are typically made using common soft foams. In order to better protect troops from Traumatic Brain Injury resulting from Improvised Explosive Devices, it is necessary to better understand the material properties involved in air blast mitigation. In this work, mitigation properties are studied using sandwich samples...

The catalytic effect of iron (III) oxide (Fe2O3) and copper (II) oxide (CuO) on an ammonium perchlorate (AP) and hydroxyl-terminated polybutadiene (HTPB) propellant was studied. High speed (5 kHz) planar laser induced fluorescence (PLIF) and visible microscopic imaging of the surface was carried out in an effort to determine the mechanisms that acc...

This study aims to characterize the interaction of explosive blast waves through simulated anatomical systems. We have developed physical models and a systematic approach for testing traumatic brain injury (TBI) mechanisms and occurrences. A simplified series of models consisting of spherical poly(methyl methacrylate) (PMMA) shells housing syntheti...

Reaction initiation in the Ni−Al heterogeneous gasless system due to thermal and mechanical stimuli was investigated. Reactive systems with different microstructures, including micro- and nanoscaled powder mixtures, as well as composite particles formed during short-term (15 min) high-energy ball milling (HEBM) of Al/Ni clad particles were examined...

High temperature (>1000 K) reaction kinetics in the stoichiometric (1:1 by molar ratio) Al-Ni system was investigated by using the, so-called, electrothermal analysis (ETA) method. ETA is the only technique that allows studying kinetics of a heterogeneous gasless reaction at temperatures above the melting points of the precursors. Special attention...

Heterogeneous gasless reactive systems, including high-energy density metal-nonmetal compositions, have seen increasing study due to their various applications. However, owing to their high reaction temperature, short reaction time, and small scale of heterogeneity, investigation of their reaction mechanisms and kinetics is very difficult. In this...

This study was conducted to quantify intracranial biomechanical responses and external blast overpressures using physical head model to understand the biomechanics of blast traumatic brain injury and to provide experimental data for computer simulation of blast-induced brain trauma. Ellipsoidal-shaped physical head models, made from 3-mm polycarbon...

The influence of short-term (5-15 min) highly energetic ball milling on the ignition characteristics of a gasless heterogeneous Ni-Al reactive system has been investigated. By using Al-Ni clad particles (30-40 microm diameter Al spheres coated by a 3-3.5 microm layer of Ni, that corresponds to a 1:1 Ni/Al atomic ratio), it was shown that such mecha...

We report an ultrafast x-ray phase-contrast imaging study of a gasless composite reactive system undergoing high heating rates (10^4 -- 2.5 x 10^5 K/s). Construction of an imaging system utilizing a high-speed CMOS camera (Vision Research Phantom v7.3) and the third-generation synchrotron at the Advanced Photon Source at Argonne National Laboratory...

Traumatic brain injury from explosive devices has become the signature wound of the U.S. armed forces in Iraq and Afghanistan [1–4]. However, due to the complicated nature of this specific form of brain injury, little is known about the injury mechanisms. Physical head models have been used in blunt and penetrating head trauma studies to obtain bio...

Thesis (Ph. D.)--University of Nevada, Reno, 2004. Includes bibliographical references (leaves 116-120) Microfiche.