Papers by Richard Behrens
Chemical Physics Letters, Dec 1, 1975
Simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS) and time-of-flight veloc... more Simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS) and time-of-flight velocity (TOF) spectra have been developed to study reactions that occur during the thermal decomposition of liquids and solids. The data obtained with these techniques are the identity of the reaction products and their rates of gas formation as a function of time. Over the past several years, these techniques have been applied to the study of energetic materials that are used in propellants and explosives. In this presentation, the details of the STMBMS and TOF velocity spectra techniques will be reviewed, the advantages of the techniques over more conventional thermal analysis and mass spectrometry measurements will be discussed, and the use of the techniques will be illustrated with results on the thermal decomposition of hexahydro-1,3,5-trinitro-s-triaine (RDX). Energetic ingredients such as RDX and HMX are used in formulating materials for use as propellants and explosives. The use of these materials requires being able to characterize their performance when used for propulsion or explosive devices and also knowing how these materials respond to heat, impact, shock and electrostatic discharge when the systems are subjected to abnormal conditions that are found in various accident scenarios. NO2 I 02N\ In our work using STMBMS and TOF velocity spectra methods, we have concentrated on understanding the reaction the initial transformation of an energetic material, such as RDX or HMX, to its intermediate products. These intermediate products undergo further reactions toward final products (i.e., N2, H20, C02 ...), releasing heat in various steps of the process. Understanding these > processes is important for developing reliable models that can predict the behavior ' of these materials under various conditions. For example, during the combustion of a propellant, the p d t i o n of released heat between the liquid layer on the burning surface and the gas phase region of the secondary flame zone will determine the burn rate characteristics of the propellant. In another example, the response of an energetic material in a slow 'cookoff" situation may either lead to a mild accident mechanisms that control FDX HMX DISTRIBUTION OF THIS DOCUMENT IS UNLIMITEDwM MASTER DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
Respondents should be aware that notwithstanding any other provision of law, no person shall be s... more Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any oenalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
Sandia National Laboratories has developed a vehicle-scale demonstration hydrogen storage system ... more Sandia National Laboratories has developed a vehicle-scale demonstration hydrogen storage system as part of a Work for Others project funded by General Motors. This Demonstration System was developed based on the properties and characteristics of sodium alanates which are complex metal hydrides. The technology resulting from this program was developed to enable heat and mass management during refueling and hydrogen delivery to an automotive system. During this program the Demonstration System was subjected to repeated hydriding and dehydriding cycles to enable comparison of the vehicle-scale system performance to small-scale sample data. This paper describes the experimental results of life-cycle studies of the Demonstration System.
OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Apr 15, 2010
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Safe and efficient hydrogen storage is a significant challenge inhibiting the use of hydrogen as ... more Safe and efficient hydrogen storage is a significant challenge inhibiting the use of hydrogen as a primary energy carrier. Although energy storage performance properties are critical to the success of solid-state hydrogen storage systems, operator and user safety is of highest importance when designing and implementing consumer products. As researchers are now integrating high energy density solid materials into hydrogen storage systems, quantification of the hazards associated with the operation and handling of these materials becomes imperative. The experimental effort presented in this paper focuses on identifying the hazards associated with producing, storing, and handling sodium alanates, and thus allowing for the development and implementation of hazard mitigation procedures. The chemical changes of sodium alanates associated with exposure to oxygen and water vapor have been characterized by thermal decomposition analysis using simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS) and Xray diffraction methods. Partial oxidation of sodium alanates, an alkali metal complex hydride, results in destabilization of the remaining hydrogen-containing material. At temperatures below 70°C, reaction of sodium alanate with water generates potentially combustible mixtures of H 2 and O 2. In addition to identifying the reaction hazards associated with the oxidation of alkali-metal containing complex hydrides, potential treatment methods are identified that chemically stabilize the oxidized material and reduce the hazard associated with handling the contaminated metal hydrides.
... Grossman, JC (Massachusetts Institute of Technology, Cambridge, MA) ; Herberg, Julie L. (Lawr... more ... Grossman, JC (Massachusetts Institute of Technology, Cambridge, MA) ; Herberg, Julie L. (Lawrence Livermore National Laboratory, Livermore, CA) ; Wagner, LK (Massachusetts Institute of Technology, Cambridge, MA) ; Peaslee, D. (University of Missouri, St. Louis, MO) ; Liu, X ...
To obtain a copy of this paper or presentation: note the name of the conference or event in the R... more To obtain a copy of this paper or presentation: note the name of the conference or event in the Resources Relation field. Other useful information can be found in the Availability, Publisher, Research Organization, Author (affiliation information) fields and/or Document ...
Jphl 7 2 1997 O S T I mmonium perchlorate (AP) and ammonium-Derchlorate-based comDos te propellan... more Jphl 7 2 1997 O S T I mmonium perchlorate (AP) and ammonium-Derchlorate-based comDos te propellants are studied using the simultaneous the&ogravime&c modulated beam mass spectrometry (Sll&MS) technique. The main objective of the present work is to evaluate whether the STMBMS can provide new data on these materials that will have sufficient detail on the reaction mechanisms and associated reaction kinetics to permit creation of a detailed model of the thermal decomposition process. Such a model is a necessary ingredient to engineering models of ignition and "slow-cookoff ' for these AP-based composite propellants. Our results show that the decomposition of pure AP is controlled by two processes. One occurs at lower temperatures (240OC to 27OoC), produces mainly H20, 02, Cl,, N,O and HCl, and is shown to occur in the solid phase within the A p particles. 200p diameter AP particles undergo 25% decomposition in the solid phase, whereas 20p diameter AP particles undergo only 13% decomposition. The second process is dissociative sublimation of AP to NH, + HClO, followed by the decomposition of, and reaction between, these two products in the gas phase. The dissociative sublimation process occurs over the entire temperature range of AP decomposition, but only becomes dominant at temperatures above those for the solid-phase decomposition. The results on the thermal decomposition of the AP-based composite propellant show several different features. First, the features of the two processes associated with the decomposition of the pure AP are still evident in the decomposition of the propellant. However, the oxidative products that evolve from the AP, such as O,, C1, and HClO,, react to various extents with the plasticizer and binder in the propellant. The evolution rates of the gaseous products from the propellant sample, formed from the decomposition of AP within the propellant, are reduced compared to their evolution rates from pure AP. This reduced rate of evolution may be due initially to diffusionlimited flow of gas out of the sample, and at later stages, due to r e d u d flow through channels created by decomposition of the Ap and binder. The reaction of the binder with HClO, occurs in a two-step sequence. First, most of the hydrogen is removed from the binder, then the remaining carbonaceous residue reacts with the oxidizers formed in the dissociative-sublimatiodgas-phase reactions of AP to form CO and CO,. The results show that the STMBMS technique can be used to provide very detailed quantitative data on the decomposition of both pure AP and AP-based composite propellants. It appears that data of sufficient detail can be obtained that will allow a detailed engineering model of the thermal decomposition process to be created. Such a model will permit prediction of: the extent of decomposition of AP, plasticizer and binder; the identities and quantities of the gaseous reaction products; and the porosity and flow characteristics of the propellant as a function of time and temperature. Inclusion of these data in a 3D thermochemical code should allow the state of an AP-based composite propellant grain to be predicted when subjected to a thermal event, such as a fire. 0 a-* Work supported by a Memorandum of Understanding between the U.S. Department of Energy and the Office of Munitions and by the U.S. Department of Energy under contract DE-AC04-94AL85000 tWRK3~~hl OF THIS bOCUMEbif IS UNLIM~EQ MA DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or P~OCPSS disdosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, p m s , or service by trade name, trademark, manufacturer, or otherwise does not necessarily cons!jtute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. ' Behrens and Minier AP-based Propellant Decomposition , Behrens and Minier AP-based Propellant Decomposition the final products, CI,, NO, O,, and H,O (step 5). Note that the higher temperature channel is observed to form NO rather than N,O as observed in the lower temperature channel.
Low Temperature Thermal Aging Samples of PETN and XTX8003 (=1 w% PETN) were aged at room temperat... more Low Temperature Thermal Aging Samples of PETN and XTX8003 (=1 w% PETN) were aged at room temperature, 50 "C, and 65 "C in acetonitrile solution. Modifiers (~0.05 M) were added to the solutions to observe the effects of various hydrolytic conditions on the PETN solutions including nitric acid, methane sulfonic acid, pure water, ammonia, and cesium hydroxide. These represent oxidizing acidic, acidic, neutral, basic, and strongly basic DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information. apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise docs not necessarily constitute or imply its endorsement, m o mmenduion, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect thosc of the United States Government or any agency thereof.
The solid phase thermal reaction chemistry of NTO between 190 and 250 C is presently being evalua... more The solid phase thermal reaction chemistry of NTO between 190 and 250 C is presently being evaluated by utilizing STMBMS, a technique that enables the authors to measure the vapor pressure of NTO and to explore the reaction mechanisms and chemical kinetics associated with the NTO thermal decomposition process. The vapor pressure of NTO is expressed as Logââ p(torr) =
The Journal of Chemical Physics, 1976
Exploratory crossed molecular beam studies of bimolecular reactions of alkaline earth dihalides w... more Exploratory crossed molecular beam studies of bimolecular reactions of alkaline earth dihalides with halogen containing compounds are reported. The c.m. product distribution is symmetric about ϑ=90° for the BaI2+Cl2 halogen-exchange reaction indicating formation of a collision complex which persists for a least a few rotational periods. The data are consistent with, but do not establish, formation of a similar complex in the SrI2+Cl2 reaction and with a statistical loose transition state energy partitioning in both reactions. The BaI2+HCl→BaICl+HI reaction is direct, favoring backscattering of the metal atom. Relative total reaction cross sections for the MX2+Cl2 halogen-exchange reactions decrease as 1.0:0.45:<0.007 when M is varied from Ba to Sr to Mg. All of these observations support an ion-pair adduct model which was previously advanced to interpret facile four-center exchange reactions of cesium halides with diatomic halogens. This model, which qualitatively correlated obse...
Council (NRC) in 1987 and has served as chairman or member of several NRC committees and panels i... more Council (NRC) in 1987 and has served as chairman or member of several NRC committees and panels including his appointment as the chairman of the Study Committee on STAR. He is also a member of the Army Science Board. MR. DAVID C. HARDISON presently supports the Department of Defense and several industrial firms as a consultant specializing in defense operations analysis. He has served as Director,
The inter- versus intra-molecular origin of the products formed in the thermal decomposition of 1... more The inter- versus intra-molecular origin of the products formed in the thermal decomposition of 1,3,5-trinitrohexahydro-S-triazine (RDX) has been traced by isotopic crossover experiments using mixtures of differently labeled analogues of RDX. The isotopic analogues of RDX used in the experiments include 2H, 13C, 15N, and 18O. The fraction of isotopic scrambling and the extent of the deuterium kinetic isotope effect (DKIE) are reported for the different thermal decomposition products. Isotopic scrambling is not observed for the N-N bond in N2O and only in small amounts (7%) in the C-H bonds in CH2O, consistent with a mechanism of their formation through methylene nitramine precursors. A product, oxy-s-triazine (OST, C3H3N3O), does not undergo isotopic scrambling in H/D, 14N/15N, or 13C/18O experiments, and its rate of formation exhibits a DKIE of 1.5. These results are consistent with the formation of OST via unimolecular decomposition of RDX. Another product, 1-nitroso-3,5-dinitrohe...
Reaction kinetics of RDX and HMX in the condensed phase. ... Maharrey, Sean P. ; Wiese-Smith, Den... more Reaction kinetics of RDX and HMX in the condensed phase. ... Maharrey, Sean P. ; Wiese-Smith, Deneille ; Behrens, Richard, Jr. ... Conference: Proposed for presentation at the JANNAF Combustion Subcommittee Meeting held June 13-17, 2005 in Charleston, SC.
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Papers by Richard Behrens