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in creator/contributor: "Simpson, R.L."

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Monolithic Nickel (II) Oxide Aerogels Using an Organic Epoxide: The Importance of the Counter Ion

The synthesis and characterization of nickel (II) oxide aerogel materials prepared using the epoxide addition method is described. The addition of the organic epoxide propylene oxide to an ethanolic solution of NiCl{sub 2} 6H{sub 2}O resulted in the formation of an opaque light green monolithic gel and subsequent drying with supercritical CO{sub 2} gave a monolithic aerogel material of the same color. This material has been characterized using powder X-ray diffraction, electron microscopy, elem… more

Date: January 13, 2004

Creator: Gash, A. E.; Satcher, J. H. & Simpson, R. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Thermal Decomposition of Trinitrotoluene (TNT) with a New One-Dimensional Time to Explosion (ODTX) Apparatus

The thermal explosion of trinitrotoluene (TNT) is used as a basis for evaluating the performance of a new One-Dimensional-Time-to-Explosion (ODTX) apparatus. The ODTX experiment involves holding a 12.7 mm-diameter spherical explosive sample under confinement (150 MPa) at a constant elevated temperature until the confining pressure is exceeded by the evolution of gases during chemical decomposition. The resulting time to explosion as a function of temperature provides valuable decomposition kine… more

Date: March 23, 2001

Creator: Tran, T. D.; Simpson, R. L.; Maienschein, J. & Tarver, Craig M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Energetic Nanocomposites with Sol-gel Chemistry: Synthesis, Safety, and Characterization

The preparation and characterization of energetic composite materials containing nanometer-sized constituents is currently a very active and exciting area of research at laboratories around the world. Some of these efforts have produced materials that have shown very unique and important properties relative to traditional energetic materials. We have previously reported on the use of sol-gel chemical methods to prepare energetic nanocomposites. Primarily we reported on the sol-gel method to syn… more

Date: June 5, 2002

Creator: Gash, A. E.; Simpson, R. L. & Satcher, J. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Nanostructured energetic materials using sol-gel methodologies

The fundamental differences between energetic composites and energetic materials made from a monomolecular approach are the energy density attainable and the energy release rates. For the past 4 years, we have been exploiting sol-gel chemistry as a route to process energetic materials on a microstructural scale. At the last ISA conference, we described four specific sol-gel approaches to fabricating energetic materials and presented our early work and results on two methods - solution crystalli… more

Date: September 27, 2000

Creator: Tillotson, T. M.; Simpson, R. L.; Hrubesh, L. W.; Gash, A. E.; Thomas, I. M. & Poco, J. F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Energetic Nanocomposites with Sol-gel Chemistry: Synthesis, Safety and Characterization

Date: May 15, 2002

Creator: Gash, A. E.; Simpson, R. L. & Satcher, J. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Synthesis and Characterization of Mixed Metal Oxide Nanocomposite Energetic Materials

In the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology, affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, prope… more

Date: November 18, 2003

Creator: Gash, A. E.; Pantoya, M. L.; Satcher, J. H. Jr.; Zhao, L.; Shea, K. J.; Simpson, R. L. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Synthesis and Characterization of a Nanocrystalline Thoria Aerogel

We report the synthesis and characterization for the first example of a low-density nanocrystalline thoria aerogel. The monolithic aerogels were prepared through the solgel polymerization of hydrated thorium nitrate in ethanol using ammonium hydroxide and propylene oxide as gelation initiators. The dried ThO{sub 2} aerogel was characterized by high-resolution transmission electron microscopy (HRTEM) and nitrogen adsorption/desorption analyses. The aerogel network was determined to be composed o… more

Date: February 4, 2004

Creator: Reibold, R. A.; Satcher, J. H. Jr.; Baumann, T. F.; Simpson, R. L. & Poco, J. F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Making nanostructured pyrotechnics in a beaker

Controlling composition at the nanometer scale is well known to alter material properties in sometimes highly desirable and dramatic ways. In the field of energetic materials component distributions, particle size, and morphology, effect both sensitivity and reactivity performance. To date nanostructured energetic materials are largely unknowns with the exception of nanometer-sized reactive powders now being produced at a number of laboratories. We have invented a new method of making nanostruc… more

Date: April 10, 2000

Creator: Gash, A. E.; Simpson, R. L.; Tillotson, T. M.; Satcher, J. H. & Hrubesh, L. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Nanotechnology Based Environmentally Robust Primers

An initiator device structure consisting of an energetic metallic nano-laminate foil coated with a sol-gel derived energetic nano-composite has been demonstrated. The device structure consists of a precision sputter deposition synthesized nano-laminate energetic foil of non-toxic and non-hazardous metals along with a ceramic-based energetic sol-gel produced coating made up of non-toxic and non-hazardous components such as ferric oxide and aluminum metal. Both the nano-laminate and sol-gel techn… more

Date: March 18, 2003

Creator: Barbee, T. W., Jr.; Gash, A. E.; Satcher, J. H. Jr. & Simpson, R. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Synthesis and Characterization of Mixed Metal Oxide Nanocomposite Energetic Materials

In the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propel… more

Date: April 27, 2004

Creator: Clapsaddle, B. J.; Gash, A. E.; Plantier, K. B.; Pantoya, M. L.; Satcher, J. S., Jr. & Simpson, R. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A versatile sol-gel synthesis route to metal-silicon mixed oxide nanocomposites that contain metal oxides as the major phase

The general synthesis of metal-silicon mixed oxide nanocomposite materials, including a variety of both main group and transition metals, in which the metal oxide is the major component is described. In a typical synthesis, the metal oxide precursor, MCl{sub x}{times}{sub y}H{sub 2}O (x=3-6, y=0-7), was mixed with the silica precursor, tetramethylorthosilicate (TMOS), in ethanol and gelled using an organic epoxide. The successful preparation of homogeneous, monolithic materials depended on the … more

Date: December 8, 2003

Creator: Clapsaddle, B. J.; Sprehn, D. W.; Gash, A. E.; Satcher, J. H. & Simpson, R. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Characterization of 2,6-Diamino-3,5-Dinitropyrazine-1-Oxide (LLM-105) as an Insensitive High Explosive Material

LLM-105 (2,6-diamino-3,5-dinitropyrazine-1-oxide) is a new molecule which has performance and insensitivity between those of HMX and TATB. Its calculated energy content is about 85% that of HMX and 15% more than that of TATB. It is thermally stable, insensitive to shock, spark and friction and has impact insensitivity level approaching that of TATB. These combined properties make it a realistic high-performance IHE material, attractive for applications that require moderate performance and inse… more

Date: April 9, 2002

Creator: Tran, T. D.; Pagoria, P. F.; Hoffman, D. M.; Cutting, J. L.; Lee, R. S. & Simpson, R. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Nanostructured energetic materials derived from sol-gel chemistry

Initiation and detonation properties are dramatically affected by an energetic material's microstructural properties. Sol-gel chemistry allows intimacy of mixing to be controlled and dramatically improved over existing methodologies. One material goal is to create very high power energetic materials which also have high energy densities. Using sol-gel chemistry we have made a nanostructured composite energetic material. Here a solid skeleton of fuel, based on resorcinol-formaldehyde, has nanocr… more

Date: March 15, 2000

Creator: Simpson, R. L.; Tillotson, T. M.; Hrubesh, L. W. & Gash, A. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

New sol-gel synthetic route to transition and main-group metal oxide aerogels using inorganic salt precursors

We have developed a new sol-gel route to synthesize several transition and main-group metal oxide aerogels. The approach is straightforward, inexpensive, versatile, and it produces monolithic microporous materials with high surface areas. Specifically, we report the use of epoxides as gelation agents for the sol-gel synthesis of chromia aerogels and xerogels from simple Cr(III) inorganic salts. The dependence of both gel formation and its rate was studied by varying the solvent used, the Cr(III… more

Date: September 12, 2000

Creator: Gash, A. E.; Tillotson, T. M.; Satcher, J. H.; Hrubesh, L. W. & Simpson, R. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Preliminary evaluation of non-hazardous explosives for security training and testing (NESTT)

A series of materials has been prepared that have authentic properties of explosives but are non-hazardous. These NESTT materials are prepared by coating a few micron layer of an explosive on a non-reactive substrate. This produces a formulation with an authentic vapor signature. Authentic x-ray and oxygen/nitrogen density signatures can also be obtained through the appropriate choice of substrate. Sensitivity tests on the materials made to date show that they are non-hazardous. One such materi… more

Date: September 1, 1993

Creator: Moody, G. L.; Pruneda, C. O.; Simpson, R. L.; Kury, J. W. & Dumais, D. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Residual stress and Raman spectra of laser deposited highly-tetrahedral-coordinated-amorphous-carbon films

We are studying carbon thin films by using a pulsed excimer laser to ablate pyrolytic graphite targets to form highly tetrahedral coordinated amorphous carbon ({alpha}t-C) films. These films have been grown on room temperature p-type Si (100) substrates without the intentional incorporation of hydrogen. In order to understand and optimize the growth of {alpha}t-C films, parametric studies of the growth parameters have been performed. We have also introduced various background gases (H{sub 2}, N… more

Date: May 1, 1994

Creator: Friedmann, T. A.; Siegal, M. P.; Tallant, D. R.; Simpson, R. L. & Dominguez, F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Deposition of DLC via intense ion beam ablation

Diamond-like carbon films were prepared by high intensity pulsed ion beam ablation of graphite targets. A 350 key, 35 kA, 400 ns pulse width beam, consisting primarily of carbon ions and protons, was focused onto a graphite target at a fluence of 15-45J/cm{sup 2}. Films were deposited onto substrates positioned i.n q n angular array from normal to the target to 90{degrees} off normal. Deposition rates up to 30 nm per pulse, corresponding to an instantaneous deposition rate greater than I mn/sec… more

Date: December 31, 1993

Creator: Johnston, G. P.; Tiwari, P.; Rej, D. J.; Davis, H. A.; Waganaar, W. J.; Muenchausen, R. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Characterization of ultradispersed aluminum

Samples of ultradispersed Al were received, which were produced by electrically exploding Al wires in argon. These samples comprised very small particles that were not significantly oxidized and that were stable in air. Particle morphology were studied with SE, micropycnometry, and gas adsorption surface area. Composition were determined using various techniques, as were thermal stability and reaction exotherms. The inexplicable reports of an Al-Ar compound and of an exothermic reaction were no… more

Date: December 8, 1994

Creator: Simpson, R. L.; Maienschein, J. L.; Swansiger, R. W.; Garcia, F. & Darling, D. H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

The unusual stability of TATB (1,3,5-triamino-2,4,6-trinitrobenzene): A review of the scientific literature

This review is intended as an up-to-date review of the scientific literature on TATB since its discovery as a high explosive. In particular, it focuses on clarifying our current understanding of the relationship between the structure of TATB and its unique thermal stability. We review a large number of different publications by many authors. A small portion of the work on TATB'' presented actually consists of experimental studies on TATB formulated as PBX-9502 or as LX-17. Where relevant, this … more

Date: July 4, 1990

Creator: Rice, S. F. & Simpson, R. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Two-Phase Flow and Heat Transfer in Multirod Geometries. Air--Water Flow Structure Data for a Round Tube, Concentric and Eccentric Annulus, and Nine-Rod Bundle.

No Description Available.

Date: January 1, 1969

Creator: Schraub, F. A.; Simpson, R. L. & Janssen, E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

A Study of Adiabatic, Fully-Developed, Annular-Dispersed Two-Phase Flow in a Vertical Round Tube.

No Description Available.

Date: January 1, 1969

Creator: Simpson, R. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Formulation and Performance of Novel Energetic Nanocomposites and Gas Generators Prepared by Sol-Gel Methods

Date: March 24, 2005

Creator: Clapsaddle, B. J.; Zhao, L.; Prentice, D.; Pantoya, M. L.; Gash, A. E.; Satcher J. H. Jr. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Development of non-hazardous explosives for security training and testing (NESTT)

A series of materials has been prepared that have authentic properties of explosives but are non-hazardous. These NESTT materials are prepared by coating a few micron thick layer of an explosive on a non-reactive substrate. This produces a formulation with an authentic vapor and molecular signature. Authentic x-ray and oxygen/nitrogen density signatures are obtained through the appropriate choice of a substrate. The signatures of NESTT TNT and NESTT Comp. C-4 have been verified by instrument an… more

Date: June 21, 1995

Creator: Kury, J. W. & Simpson, R. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Characterization of TNAZ

The explosive TNAZ has recently become available in pilot-plant quantities. We have found its small-scale safety properties similar to those of other nitramines. Detonation calorimetry showed TNAZ to have 96% the energy of HMX and 150% of TNT. The shock sensitivity of neat TNAZ is greater than LX-14. A retonation wave was observed when the material was shocked at 2.0 GPa. The initiation behavior of neat TNAZ cannot be classified as either homogeneous or heterogeneous. Six plastic bonded TNAZ-ba… more

Date: December 14, 1994

Creator: Simpson, R. L.; Garza, R. G.; Foltz, M. F.; Ornellas, D. L. & Utriew, P. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department