Solid Rocket Fuels Research Articles

Development of an extraction method for perchlorate in soils

Perchlorate originates as a contaminant in the environment from its use in solid rocket fuels and munitions. The current US EPA methods for perchlorate determination via ion chromatography using conductivity detection do not include recommendations for the extraction of perchlorate from soil. This study evaluated and identified appropriate conditions for the extraction of perchlorate from clay loam, loamy sand, and sandy soils. Based on the results of this evaluation, soils should be extracted in a dry, ground (mortar and pestle) state with Milli-Q water in a 1 ratio 1 soil ratio water ratio and diluted no more than 5-fold before analysis. When sandy soils were extracted in this manner, the calculated method detection limit was 3.5 microg kg(-1). The findings of this study have aided in the establishment of a standardized extraction method for perchlorate in soil.

Optimization of operating conditions for the determination of perchlorate in biological samples using preconcentration/preelution ion chromatography

Perchlorate originates as a contaminant in the environment from the use of salts in the manufacture of solid rocket fuels and munitions. Monitoring potential perchlorate contamination in the environment is of interest, however, very few analytical methods have been developed for perchlorate determination in biological samples. Analysis of complex samples by ion chromatography is complicated by matrix components that can interfere with perchlorate determination. However, a recently developed preconcentration/preelution (PC/PE) ion chromatography method has demonstrated the capability to analyze certain complex samples such as high salinity water, milk, and hydroponic fertilizers. The ability of this method to reduce sample background and lower detection limits in ion chromatography for various biological samples was evaluated in this study. The PC/PE method was applicable to the analysis of kidneys, livers, zebrafish, quail eggs, lettuce, and urine. Optimal operating conditions were determined for each matrix. Ranges of optimal wash volumes were shorter when 15 mM NaOH prewash solutions were used compared with 10 mM and good recovery was achieved for most matrices with an injection period ≥60 s. Prewash solution concentration did not appear to significantly affect matrix background. The PC/PE method was capable of reducing sample background when compared to EPA Method 314.0, which resulted in detection limits, with the exception of zebrafish and urine, that were two-fold lower than those achieved with EPA Method 314.0.

Temperature and Pressure Sensitivities of Burning Wave Parameters of Nitramine-Containing Propellants and HMX

Burning rate and burning surface temperatures have been obtained experimentally for modern double-base propellants containing nitramine additives and for HMX. Temperature sensitivities of burning wave parameters were estimated from the experimental data measured at pressures of 20 and 100 atm and at sample temperatures of i 80, +20, +100 C. Evaluation of standard deviations of the estimations shows that smoothing procedures for dependencies of burning wave parameters on pressure and temperature are necessary to obtain correct values of thesensitivities. Calculations ofthecriteria forstable combustion show that Novozhilov’ s [Novozhilov, B. V., “ Nonstationary Combustion of Solid Rocket Fuels,” Nauka, Moscow, 1973 (Translation AFSC FTD-MD-24-317-74) (in Russian) and Novozhilov, B. V., “ Theory of Nonsteady Burning and Combustion Stability of Solid Propellants by Zel’ dovich‐ Novozhilov Method,” Nonsteady Burning and Combustion Stability of Solid Propellants , edited by L. DeLuca, E.W. Price,and M. Summere eld, Vol. 143,Progressin Astronauticsand Aeronautics,AIAA,Washington, DC, 1992, Chap. 15, pp. 601‐ 641] criterion correctly predicts regimes of stable combustion of the propellants and HMX. An analysis of burned surface irregularities of the propellants cone rms one-dimensional character of the combustion under the investigated conditions.

99/00006 Bis(methyl-NON-azoxy)formal as a potential component of a mixed oxidizing agent for solid rocket fuels

99/00006 Bis(methyl-NON-azoxy)formal as a potential component of a mixed oxidizing agent for solid rocket fuels

98/03497 Energetics of solid rocket fuels with a decreased ecological danger

98/03497 Energetics of solid rocket fuels with a decreased ecological danger

98/01012 Combining HCI in combustion of solid rocket fuels: Marshakov, V. N. et al. Khim. Fiz., 1997, 16, (9), 85–90. (in Russian)

98/01012 Combining HCI in combustion of solid rocket fuels: Marshakov, V. N. et al. Khim. Fiz., 1997, 16, (9), 85–90. (in Russian)

Effect of specimen size on bend properties of doped molybdenum: Y. Hiraoka et al. (Okayama University of Science, Okayama, Japan.) J.Japan Soc. Powder and Powder Metallurgy, vol 42, no 8, 1995, 964–968. (In English.)

Dust particles with diameters below 100 μm represent an important part of the space environment. Objects like satellites or spacecrafts, are constantly bombarded with particles of cosmic velocities of 10 km/s and more. These hypervelocity impacts lead to evaporation of a large fraction of these particles and to the formation of craters on the material surfaces which exhibit diameters which are up to one order of magnitude larger than the impinging particles. This results in a remarkable materials degradation of space exposed surfaces which can considerably reduce the life time e.g. of semiconductor panels for the generation of energy, due to the cumulative effect of a multitude of such particles which hit a surface during a certain time.The particle population in space near to earth consists of two distinct groups:(a)Natural particles, micrometeorites: These particles are a natural part of the space environment and cannot be avoided. Most of them have so-called “chondritic” compositions and consist of Si, Al, Mg, Fe, Ca and O, an elemental makeup resembling the bulk composition of the original solar nebula from which our solar system and the planets formed 4.5 billion years ago.(b)Man made debris particles: These stem from various sources, e.g. exhausts from solid rocket fuels, paint chips, fragments from space crafts etc. These particles pose an increasing danger to space flight and their future production must be reduced by strict debris policies.The important question was now:What percentage of impact particles is man-made?Cosmic and man-made particles exhibit different chemical compositions. Hence, a micro-chemical analysis of particle impacts on satellite surfaces can be used to determine the particle ratio. For this purpose, the LDEF-experiment (Long Duration Exposure Facility) was launched by NASA in 1984 to study erosion phenomena on material surfaces (of more than 10,000 test samples) in a Low Earth Orbit (LEO)-environment. LDEF was retrieved only in 1990 because of the Challenger disaster which essentially delayed the retrieval up to the last moment before the experimental setup would have been destroyed upon entrance into the earth atmosphere.The demonstration of pronounced material degradation of space exposed materials logically leads to the question which materials are used in space technology. Plansee SE in Reutte/Tyrol has quite a tradition in the production of smaller rocket nozzles, e.g. satellite propulsion nozzles and general propulsion components made of Mo, W, Nb or Ta-based alloys. The W–Ag evaporation cooled alloy was among the earliest materials for rocket combustion chambers enduring ultra high temperatures due to partial evaporation of the silver which thereby cooled the chamber. Ni- and Fe-based ODS superalloys find application in durable TPS/hot structures of hypersonic vehicles, e.g. as honeycomb panels and fasteners of PM 1000/2000. These are PM-ferritic and nickel based oxide dispersion strengthened alloys. We have studied the significance of Yttrium depletion within the oxide scales of these alloys.

Applied analytical tools for the characterization of cermets

Dust particles with diameters below 100 μm represent an important part of the space environment. Objects like satellites or spacecrafts, are constantly bombarded with particles of cosmic velocities of 10 km/s and more. These hypervelocity impacts lead to evaporation of a large fraction of these particles and to the formation of craters on the material surfaces which exhibit diameters which are up to one order of magnitude larger than the impinging particles. This results in a remarkable materials degradation of space exposed surfaces which can considerably reduce the life time e.g. of semiconductor panels for the generation of energy, due to the cumulative effect of a multitude of such particles which hit a surface during a certain time.The particle population in space near to earth consists of two distinct groups:(a)Natural particles, micrometeorites: These particles are a natural part of the space environment and cannot be avoided. Most of them have so-called “chondritic” compositions and consist of Si, Al, Mg, Fe, Ca and O, an elemental makeup resembling the bulk composition of the original solar nebula from which our solar system and the planets formed 4.5 billion years ago.(b)Man made debris particles: These stem from various sources, e.g. exhausts from solid rocket fuels, paint chips, fragments from space crafts etc. These particles pose an increasing danger to space flight and their future production must be reduced by strict debris policies.The important question was now:What percentage of impact particles is man-made?Cosmic and man-made particles exhibit different chemical compositions. Hence, a micro-chemical analysis of particle impacts on satellite surfaces can be used to determine the particle ratio. For this purpose, the LDEF-experiment (Long Duration Exposure Facility) was launched by NASA in 1984 to study erosion phenomena on material surfaces (of more than 10,000 test samples) in a Low Earth Orbit (LEO)-environment. LDEF was retrieved only in 1990 because of the Challenger disaster which essentially delayed the retrieval up to the last moment before the experimental setup would have been destroyed upon entrance into the earth atmosphere.The demonstration of pronounced material degradation of space exposed materials logically leads to the question which materials are used in space technology. Plansee SE in Reutte/Tyrol has quite a tradition in the production of smaller rocket nozzles, e.g. satellite propulsion nozzles and general propulsion components made of Mo, W, Nb or Ta-based alloys. The W–Ag evaporation cooled alloy was among the earliest materials for rocket combustion chambers enduring ultra high temperatures due to partial evaporation of the silver which thereby cooled the chamber. Ni- and Fe-based ODS superalloys find application in durable TPS/hot structures of hypersonic vehicles, e.g. as honeycomb panels and fasteners of PM 1000/2000. These are PM-ferritic and nickel based oxide dispersion strengthened alloys. We have studied the significance of Yttrium depletion within the oxide scales of these alloys.

Role of the diamond-substrate interface in chemical vapour deposition (CVD) of diamond

Dust particles with diameters below 100 μm represent an important part of the space environment. Objects like satellites or spacecrafts, are constantly bombarded with particles of cosmic velocities of 10 km/s and more. These hypervelocity impacts lead to evaporation of a large fraction of these particles and to the formation of craters on the material surfaces which exhibit diameters which are up to one order of magnitude larger than the impinging particles. This results in a remarkable materials degradation of space exposed surfaces which can considerably reduce the life time e.g. of semiconductor panels for the generation of energy, due to the cumulative effect of a multitude of such particles which hit a surface during a certain time.The particle population in space near to earth consists of two distinct groups:(a)Natural particles, micrometeorites: These particles are a natural part of the space environment and cannot be avoided. Most of them have so-called “chondritic” compositions and consist of Si, Al, Mg, Fe, Ca and O, an elemental makeup resembling the bulk composition of the original solar nebula from which our solar system and the planets formed 4.5 billion years ago.(b)Man made debris particles: These stem from various sources, e.g. exhausts from solid rocket fuels, paint chips, fragments from space crafts etc. These particles pose an increasing danger to space flight and their future production must be reduced by strict debris policies.The important question was now:What percentage of impact particles is man-made?Cosmic and man-made particles exhibit different chemical compositions. Hence, a micro-chemical analysis of particle impacts on satellite surfaces can be used to determine the particle ratio. For this purpose, the LDEF-experiment (Long Duration Exposure Facility) was launched by NASA in 1984 to study erosion phenomena on material surfaces (of more than 10,000 test samples) in a Low Earth Orbit (LEO)-environment. LDEF was retrieved only in 1990 because of the Challenger disaster which essentially delayed the retrieval up to the last moment before the experimental setup would have been destroyed upon entrance into the earth atmosphere.The demonstration of pronounced material degradation of space exposed materials logically leads to the question which materials are used in space technology. Plansee SE in Reutte/Tyrol has quite a tradition in the production of smaller rocket nozzles, e.g. satellite propulsion nozzles and general propulsion components made of Mo, W, Nb or Ta-based alloys. The W–Ag evaporation cooled alloy was among the earliest materials for rocket combustion chambers enduring ultra high temperatures due to partial evaporation of the silver which thereby cooled the chamber. Ni- and Fe-based ODS superalloys find application in durable TPS/hot structures of hypersonic vehicles, e.g. as honeycomb panels and fasteners of PM 1000/2000. These are PM-ferritic and nickel based oxide dispersion strengthened alloys. We have studied the significance of Yttrium depletion within the oxide scales of these alloys.

Modeling of Solid Rocket Fuel: From Quantum Chemistry to Fluid Dynamics Simulations

First Page

Methodology of studying the fracture of solid rocket fuels

1. We studied the fracture toughness of solid rocket fuel using JIc and Jc (Andrews parameter), and we established that the material is sensitive to strain rate. Despite the paucity of reliable empirical data, it was determined that a fracture toughness maximum is attained in the strain-rate range 10−1−1 sec−1 and is probably due to the glass transition in the material. However, this should be corroborated by studies conducted at different temperatures. 2. The effect of the type of specimen on fracture toughness was examined, although no definitive conclusions can be made due to the scatter. 3. A comparison was made of two energy criteria, Rice's J-integral and Andrews' generalized theory. The latter is used for tensile specimens with a unilateral notch. Since the results obtained from both of these criteria are very close, they are equivalent for evaluating the parameter dU/dA. 4. The Andrews theory was used to obtain only a small amount of information, but we hope that our results will prove useful in further studies — particularly in the study of polymers, which are characterized by large nonlinear strains. Such materials have not been examined in other theories.

Effect of mechanical stresses on the combustion velocity of mixed solid fuels

It is well-known that the velocity of stationary combustion of mixed solid rocket fuels depends on the stressed state in them. A theoretical description of the effect of mechanical stresses on the combustion velocity of solid rocket fuels should be based on the one hand on the theory of combustion of condensed fuels, taking into account their complex multizone structure and, on the other hand, on the description of the changes of properties of the near-surface layer as a result of the stressed state of the fuel. In particular, it is necessary to describe the origination of gas permeability anisotropy of the near-surface layer. In accordance with the concepts developed in this paper, the combustion velocity of a solid fuel, subjected to tension, is different depending on the direction of combustion. Combustion from a surface parallel to the stretching force takes place with a higher velocity than in an orthogonal direction. Repeated deformations of the sample can lead to the buildup of defects and cracks, and can cause an even greater increase of the combustion velocity in the stressed state.

Effects of Solid Rocket Fuel Exhaust on Honey Bee 1 Colonies 2

All honey bee, Apis mellifera , colonies exposed to solid rocket fuel exhaust suffered depressed brood production. Two colonies were unable to recover. Honey production was depressed or absent in medium- and high-exposure colonies. Stress diseases were observed in all medium- and low-exposure colonies, aggression was considerably increased in low-exposure colonies, and high-exposure colonies were invaded by wax moths. The space shuttle flights may cause the stimulation of aggressive behavior of colonies near the launch site and increased susceptibility of repeatedly exposed colonies to stress-related diseases; however, repeated exposure of hives is not anticipated.

Crack Propagation in Double-Base Propellants

Crack propagation tests were conducted on a composite modified double-base (CMDB) propellant with the use of center-cracke d strip biaxial specimens. Constant strain rate tests were conducted at several temperatures (40-105°F) and crosshead rates (0.02-200 in./min) to define the crack initiation and propagation characteristics for monotonically increasing strain history. The tests were conducted at ambient, 250, and 500 psig pressure to evaluate the effect of pressure on initiation and crack velocity. A second series of tests was conducted to evaluate the effect of a prestrain damage history on crack propagation. In the second series, the samples (without precut cracks) were initially prestrained to 15-25% and held for a period of time to induce material damage. After load release and sufficient recovery time, cracks were inserted in the specimens and they were then pulled to failure at a constant strain rate. Similar tests were conducted on round, notched tensile samples to define the critical stress intensity factor (Klc) and to provide a comparison between uniaxial and biaxial fracture initiation. Schapery's viscoelastic fracture theory was used to evaluate the crack velocity data under constant strain rate conditions. One important result of the study was the finding that the crack velocity depended rather strongly on imposed strain level. I. Introduction C RACK initiation and propagation in polymeric materials has been given considerable attention during the last 15 years, stimulated primarily by their unique viscoelastic behavior and also by the use of polymerics as solid propellant rocket fuels. Filled polymers are used extensively as solidpropellant grains which must undergo a variety of environmental loading conditions, during motor storage and handling and during actual operational firing conditions, which impose pressure loads at high rates and for relatively long times. The consequence of a crack can be the failure of the rocket motor as a result of overpressuriz ation, case burnthrough, erratic pressure-time response, or a variety of events related to structural or ballistic performance failure. The primary work over the last decade has been aimed at defining the laws which govern crack initiation, propagation, and trajectory under motorlike operational conditions to arrive at an assessment of overall crack criticality for a given rocket motor system. A number of investigators have studied viscoelastic crack propagation in polymers and solid propellants. l~l°

Storage stability of solid rocket fuels. 2. Effect of oxidizer loadings

Ageing behaviour, leading to ballistic changes, has been studied as a function of oxidizer loading in polystyrene/ammonium perchlorate solid-propellants. The ageing studies were carried out at 100 °C in air. Change in burning rate decreased as the oxidizer loading increased from 75 to 80%. The change in thermal decomposition rates both at 230 and 260 °C also decreased as the oxidizer loading in the propellants increased. The shapes of the plots of the changes in burning rate and thermal decomposition rate (230 and 260 °C) at different storage times for different oxidizer-loaded propellants seem to be exactly similar. These results lead to the conclusion that the thermal decomposition of the propellant may be responsible for bringing about the ballistic changes during the ageing process. Infrared studies of the binder portion of the aged propellant indicate that peroxide formation takes place during the course of ageing and that peroxide formation for a particular storage time and temperature increases as the loading decreases.