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Kinetics of (beta)(right arrow)(delta) Solid-Solid Phase Transition of HMX

Description: In order to calculate the kinetic parameters from DSC data, we have used the generally accepted methods of Bershtein [13]. We have calculated the rate constants for 4 temperatures and the activation energy based on the shift in the transition temperature, {beta} {yields} {delta} for HMX. The values of E{sub a} from this work is 402 kJ/mol compared to previous results by Brill [9] of 204 kJ/mol. Brill and associates measured the phase transition of HMX using FTIR, sodium chloride plates and sili… more
Date: September 1, 2000
Creator: Weese, R K
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Cookoff response of PBXN-109: material characterization and ALE3D model

Description: Materials properties measurements are made for the RDX-based explosive, PBXN-109, and an initial ALE3D model for cookoff is discussed. A significant effort is underway in the U.S. Navy and Department of Energy (DOE) laboratories to understand the thermal explosion behavior of this material. Benchmark cookoff experiments are being performed by the U.S. Navy to validate DOE materials models and computer codes. The ALE3D computer code can model the coupled thermal, mechanical, and chemical behavio… more
Date: October 24, 2000
Creator: McClelland, M A; Tran, T D; Cunningham, B J; Weese, R K & Maienschein, J L
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Cookoff Response of PBXN-109: Material Characterization and ALE3D Thermal Predictions

Description: Materials properties measurements are made for the RDX-based explosive, PBXN-109, and initial ALE3D model predictions are given for the cookoff temperature in a U.S. Navy test. This work is part of an effort in the U.S. Navy and Department of Energy (DOE) laboratories to understand the thermal explosion behavior of this material. Benchmark cookoff experiments are being performed by the U.S. Navy to validate DOE materials models and computer codes. The ALE3D computer code can model the coupled t… more
Date: May 29, 2001
Creator: McClelland, M A; Tran, T D; Cunningham, B J; Weese, R K & Maienschein, J L
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Cookoff Response of PBXN-109: Material Characterization and ALE3D Thermal Predictions

Description: Materials properties measurements are made for the RDX-based explosive, PBXN-109, and initial ALE3D model predictions are given for the cookoff temperature in a U.S. Navy test. This work is part of an effort in the U.S. Navy and Department of Energy (DOE) laboratories to understand the thermal explosion behavior of this material. Benchmark cookoff experiments are being performed by the U.S. Navy to validate DOE materials models and computer codes. The ALE3D computer code can model the coupled t… more
Date: August 21, 2001
Creator: McClelland, M A; Tran, T D; Cunningham, B J; Weese, R K & Maienschein, J L
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Kinetics of the {beta} {yields} {delta} Solid-Solid Transition of HMX, Octahydro-1,3,5,7-Tetranitro-1,3,5,7-Tetrazocine

Description: We apply Differential Scanning Calorimetry, DSC, to measure the kinetics of the {beta} {yields} {delta} solid-solid phase transition of Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocinet HMX. Integration of the DSC signal gives a direct measurement of degree of conversion. We apply 1st order kinetics, the Ozawa method, and isoconversional analysis to show that the phase transition is not a simple one-step reaction, but instead is a complex combination of steps. The range of activation energies f… more
Date: September 5, 2001
Creator: Weese, R K; Maienschein, J L & Perrino, C T
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Understanding and Predicting the Thermal Explosion Violence of HMX-Based and RDX-Based Explosives - Experimental Measurements of Material Properties and Reaction Violence

Description: The violence of thermal explosions with energetic materials is affected by many material properties, including mechanical and thermal properties, thermal ignition kinetics, and deflagration behavior. These properties must be characterized for heated samples as well as pristine materials. We present available data for these properties for two HMX-based formulations--LX-04 and PBX-9501, and two RDX-based formulations--Composition B and PBXN-109. We draw upon separately published data on the therm… more
Date: July 3, 2002
Creator: Maienschein, J L; Wardell, J F; Weese, R K; Cunningham, B J & Tran, T D
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Energetic Materials and Atomic Force Microscopy: Structure and Kinetics

Description: Understanding the structure and composition of energetic materials at the sub-micron level is imperative for the fundamental studies of hot-spot formation and structural composition of energetic materials. Using in situ high-temperature AFM we have observed the solid-solid phase transition of Octahydro-1,3,5,7,-tetrazocine, HMX, in real time. Massive surface reconstruction occurs during the 1st-order transition. The temperature induced increase in void space and surface roughness observed in th… more
Date: July 31, 2002
Creator: Weeks, B.L.; Weese, R.K. & Zaug, J.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Thermal Conductivity of Tetryl by Modulated Differential Scanning Calorimetry

Description: We investigated the use of the Modulated Differential Scanning Calorimeter to measure thermal conductivity (K) of the explosive, Tetryl, using two different methods, isothermal and nonthermal. A discussion of our methods and a comparison of our measured values to literature values of K for Tetryl, which deviated by as much as 50%, will be presented.
Date: July 28, 2003
Creator: Weese, R. K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Thermal Decomposition Kinetics of HMX

Description: Nucleation-growth kinetic expressions are derived for thermal decomposition of HMX from a variety of types of data, including mass loss for isothermal and constant rate heating in an open pan, and heat flow for isothermal and constant rate heating in open and closed pans. Conditions are identified in which thermal runaway is small to nonexistent, which typically means temperatures less than 255 C and heating rates less than 1 C/min. Activation energies are typically in the 140 to 150 kJ/mol reg… more
Date: May 5, 2004
Creator: Burnham, A K & Weese, R K
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A Distributed Activation Energy Model of Thermodynamically Inhibited Nucleation and Growth Reactions and its Application to the beta-delta Phase Transition of HMX

Description: Detailed and global models are presented for thermodynamically inhibited nucleation-growth reactions and applied to the {beta}-{delta} Phase Transition of HMX (nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine). The detailed model contains separate kinetic parameters for the nucleation process, including an activation energy distribution resulting from a distribution of defect energies, and for movement of the resulting reaction interface within a single particle. A thermodynamic inhib… more
Date: June 18, 2004
Creator: Burnham, A K; Weese, R K & Weeks, B L
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Kinetics of thermal Degradation of Explosive Binders Viton A, Estane, and Kel-F

Description: The use of isoconversional, sometimes called model-free, kinetic analysis methods have recently gained favor in the thermal analysis community. Although these methods are very useful and instructive, the conclusion by some that model fitting is a poor approach is largely due to improper use of model fitting, such as fitting a single heating rate or multiple heating rates separately. The current paper shows the ability of model fitting to correlate reaction data over very wide time-temperature r… more
Date: July 16, 2004
Creator: Burnham, A K & Weese, R K
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Distributed Activation Energy Model of Thermodynamically Inhibited Nucleation and Growth Reactions and its Application to the Phase Transition of HMX

Description: Detailed and global models are presented for thermodynamically inhibited nucleation-growth reactions and applied to the {beta}-{delta} Phase Transition of HMX (nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine). The detailed model contains separate kinetic parameters for the nucleation process, including an activation energy distribution resulting from a distribution of defect energies, and for movement of the resulting reaction interface within a single particle. A thermodynamic inhib… more
Date: July 20, 2004
Creator: Burnham, A K; Weese, R K & Weeks, B L
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Model-Fitting Approach to Characterizing Polymer Decomposition Kinetics

Description: The use of isoconversional, sometimes called model-free, kinetic analysis methods have recently gained favor in the thermal analysis community. Although these methods are very useful and instructive, the conclusion that model fitting is a poor approach is largely due to improper use of the model fitting approach, such as fitting each heating rate separately. The current paper shows the ability of model fitting to correlate reaction data over very wide time-temperature regimes, including simulta… more
Date: July 20, 2004
Creator: Burnham, A K & Weese, R K
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Decomposition Kinetics for Mass Loss and Heat Released for HMX

Description: Nucleation-growth kinetic expressions are derived for thermal decomposition of HMX from a variety of types of data, including mass loss for isothermal and constant rate heating in an open pan, and heat flow for isothermal and constant rate heating in open and closed pans. Conditions are identified in which thermal runaway is small to nonexistent, which typically means temperatures less than 255 C and heating rates less than 1 C/min. Activation energies are typically in the 140 to 150 kJ/mol reg… more
Date: July 27, 2004
Creator: Weese, R K & Burnham, A K
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Coefficient of Thermal Expansion of the Beta and Delta Polymorphs of HMX

Description: Dimensional changes related to temperature cycling of the beta and delta polymorphs of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) are important for a variety of applications. The coefficient of thermal expansion (CTE) of the beta and delta phases are measured and reported in this work over a temperature range of -20 C to 215 C. In addition, dimensional changes associated with the phase transition were measured, both through the transition and back down. Initially, differential scann… more
Date: August 5, 2004
Creator: Weese, R K; Burnham, A K & Maienschein, J L
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Kinetics of HMX and CP Decomposition and Their Extrapolation for Lifetime Assessment

Description: Decomposition kinetics are determined for HMX (nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) and CP (2-(5-cyanotetrazalato) pentaammine cobalt (III) perchlorate) separately and together. For high levels of thermal stress, the two materials decompose faster as a mixture than individually. This effect is observed both in high-temperature thermal analysis experiments and in long-term thermal aging experiments. An Arrhenius plot of the 10% level of HMX decomposition by itself from a d… more
Date: November 18, 2004
Creator: Burnham, A K; Weese, R K & Andrzejewski, W J
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Thermal Decomposition Kinetics of HMX

Description: Nucleation-growth kinetic expressions are derived for thermal decomposition of HMX from a variety of thermal analysis data types, including mass loss for isothermal and constant rate heating in an open pan and heat flow for isothermal and constant rate heating in open and closed pans. Conditions are identified in which thermal runaway is small to nonexistent, which typically means temperatures less than 255 C and heating rates less than 1 C/min. Activation energies are typically in the 140 to 1… more
Date: November 18, 2004
Creator: Burnham, A K & Weese, R K
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Coefficient of Thermal Expansion of the Beta and Delta Polymorphs of HMX

Description: Dimensional changes related to temperature cycling of the {beta} and {delta} polymorphs of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) are important for a variety of applications. The coefficient of thermal expansion (CTE) of the {beta} and {delta} phases are measured over a temperature range of -20 C to 215 C by thermo-mechanical analysis (TMA). Dimensional changes associated with the phase transition were also measured, and the time-temperature dependence of the dimensional change … more
Date: January 11, 2005
Creator: Weese, R K & Burnham, A K
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Kinetics of HMX and CP Decomposition and Their Extrapolation for Lifetime Assessment

Description: Decomposition kinetics are determined for HMX (nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) and CP (2-(5-cyanotetrazalato) pentaammine cobalt (III) perchlorate) separately and together. For high levels of thermal stress, the two materials decompose faster as a mixture than individually. This effect is observed both in high-temperature thermal analysis experiments and in long-term thermal aging experiments. An Arrhenius plot of the 10% level of HMX decomposition by itself from a d… more
Date: March 10, 2005
Creator: Burnham, A K; Weese, R K & Andrzejewski, W J
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Thermal Decomposition Kinetics of HMX

Description: Nucleation-growth kinetic expressions are derived for thermal decomposition of HMX from a variety of types of data, including mass loss for isothermal and constant rate heating in an open pan, and heat flow for isothermal and constant rate heating in open and closed pans. Conditions are identified in which thermal runaway is small to nonexistent, which typically means temperatures less than 255 C and heating rates less than 1 C/min. Activation energies are typically in the 140 to 165 kJ/mol reg… more
Date: March 17, 2005
Creator: Burnham, A K & Weese, R K
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

CP: AN INVESTIGATION OF COEFFICIENT OF THERMAL EXPANSION, DECOMPOSITION KINETICS, AND REACTION TO VARIOUS STIMULI

Description: The properties of pentaamine (5-cyano-2H-tetrazolato-N2) cobalt (III) perchlorate (CP), which was first synthesized in 1968, continues to be of interest for predicting behavior in handling, shipping, aging, and thermal cook-off situations. We report coefficient of thermal expansion (CTE) values over four specific temperature ranges, decomposition kinetics using linear heating rates, and the reaction to three different types of stimuli: impact, spark, and friction. The CTE was measured using a T… more
Date: March 23, 2005
Creator: Weese, R. K.; Burnham, A. K. & Fontes, A. T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A STUDY OF THE PROPERTIES OF CP: COEFFICIENT OF THERMAL EXPANSION, DECOMPOSITION KINETICS AND REACTION TO SPARK, FRICTION AND IMPACT

Description: The properties of pentaamine (5-cyano-2H-tetrazolato-N2) cobalt (III) perchlorate (CP), which was first synthesized in 1968, continues to be of interest for predicting behavior in handling, shipping, aging, and thermal cook-off situations. We report coefficient of thermal expansion (CTE) values over four specific temperature ranges, decomposition kinetics using linear heating rates, and the reaction to three different types of stimuli: impact, spark, and friction. The CTE was measured using a T… more
Date: March 30, 2005
Creator: Weese, R K; Burnham, A K & Fontes, A T
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Thermal Properties of FOX-7

Description: Much effort has been devoted to an ongoing search for more powerful, safer and environmentally friendly explosives. Since it was developed in the late 1990s, 1,1-diamino-2,2-dinitroethene (FOX-7), with lower sensitivity and comparable performance to RDX, has received increasing interest. Preliminary results on the physical and chemical characterization of FOX-7 have shown that it possesses good thermal and chemical stability. It is expected that FOX-7 will be a new important explosive ingredien… more
Date: March 30, 2005
Creator: Burnham, A K; Weese, R K; Wang, R; Kwok, Q M & Jones, D G
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Physical Characterization of RX-55-AE-5 A formulation of 97.5 % 2, 6-diamino-3, 5-dinitropyrazine-1-oxide (LLM 105) and 2.5 % Viton A

Description: With the use of modern tools such as molecular modeling on increasingly powerful computers, new materials can be evaluated by their structural activity relationships, SAR, and their approximate physical and chemical properties can be calculated in some cases with surprising accuracy. These new capabilities enable streamlined synthetic routes based on safety, performance and processing requirements, to name a few [1]. Current work includes both understanding properties of old explosives and meas… more
Date: June 8, 2005
Creator: Weese, R K; Burnham, A K; Turner, H C & Tran, T
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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