The Experts below are selected from a list of 8745 Experts worldwide ranked by ideXlab platform
Edward Todd Urbansky - One of the best experts on this subject based on the ideXlab platform.
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Perchlorate as an environmental contaminant
Environmental Science and Pollution Research, 2002Co-Authors: Edward Todd UrbanskyAbstract:Perchlorate anion (ClO4-) has been found in drinking water supplies throughout the southwestern United States. It is primarily associated with releases of ammonium perchlorate by defense contractors, military operations, and aerospace programs. Ammonium perchlorate is used as a solid oxidant in missile and Rocket Propulsion systems. Traces of perchlorate are found in Chile saltpeter, but the use of such fertilizer has not been associated with large scale contamination. Although it is a strong oxidant, perchlorate anion is very persistent in the environment due to the high activation energy associated with its reduction. At high enough concentrations, perchlorate can affect thyroid gland functions, where it is mistakenly taken up in place of iodide. A safe daily exposure has not yet been set, but is expected to be released in 2002. Perchlorate is measured in environmental samples primarily by ion chromatography. It can be removed by anion exchange or membrane filtration. It is destroyed by some biological and chemical processes. The environmental occurrence, toxicity, analytical chemistry, and remediative approaches are discussed.
Luigi T Deluca - One of the best experts on this subject based on the ideXlab platform.
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Innovative Methods to Enhance the Combustion Properties of Solid Fuels for Hybrid Rocket Propulsion
MDPI AG, 2019Co-Authors: Suhang Chen, Yue Tang, Wei Zhang, Ruiqi Shen, Luigi T DelucaAbstract:The low regression rates for hydroxyl-terminated polybutadiene (HTPB)-based solid fuels and poor mechanical properties for the alternative paraffin-based liquefying fuels make today hybrid Rocket engines far from the outstanding accomplishments of solid motors and liquid engines. In this paper, a survey is conducted of several innovative methods under test to improve solid fuel properties, which include self-disintegration fuel structure (SDFS)/paraffin fuels, paraffin fuels with better mechanical properties, high thermal conductivity fuels and porous layer combustion fuels. In particular, concerning HTPB, new results about diverse insert and low-energy polymer particles enhancing the combustion properties of HTPB are presented. Compared to pure HTPB, regression rate can be increased up to 21% by adding particles of polymers such as 5% polyethylene or 10% oleamide. Concerning paraffin, new results about self-disintegrating composite fuels incorporating Magnesium particles (MgP) point out that 15% 1 μm- or 100 μm-MgP formulations increase regression rates by 163.2% or 82.1% respectively, at 335 kg/m2·s oxygen flux, compared to pure paraffin. Overall, composite solid fuels featuring self-disintegration structure appear the most promising innovative technique, since they allow separating the matrix regression from the combustion of the filler grains. Yet, the investigated methods are at their initial stage. Substantial work of refinement in this paper is for producing solid fuels to fulfill the needs of hybrid Rocket Propulsion
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Overview of Al-based nanoenergetic ingredients for solid Rocket Propulsion
Elsevier, 2018Co-Authors: Luigi T DelucaAbstract:The introduction of nano-sized energetic ingredients first occurred in Russia about 60 years ago and arose great expectations in the Rocket Propulsion community, thanks to the higher energy densities and faster energy release rates exhibited with respect to conventional ingredients. But, despite intense worldwide research programs, still today mostly laboratory level applications are reported and often for scientific purposes only. A number of practical reasons prevent the applications at industrial level: inert native coating of the energetic particles, nonuniform dispersion, aging, excessive viscosity of the slurry propellant, possible limitations in mechanical properties, more demanding safety issues, cost, and so on. This paper describes the main features in terms of performance of solid Rocket propellants loaded with nanometals and intends to emphasize the unique properties or operating conditions made possible by the addition of the nano-sized energetic ingredients. Steady and unsteady combustion regimes are examined. Keywords: Nanoaluminum, Solid Rocket propellant, Burning rate, Combustion, Propulsion, Performanc
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aggregation and incipient agglomeration in metallized solid propellants and solid fuels for Rocket Propulsion
46th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit, 2010Co-Authors: Luigi T Deluca, Christian Paravan, A Reina, Elisa Marchesi, F Maggi, A Bandera, G Colombo, B M KosowskiAbstract:Metal fuels are commonly used as high-energy ingredients in both solid and hybrid Rocket Propulsion systems. However, aggregation and agglomeration effects can sensibly modify ballistic properties and anyhow reduce the delivered specific impulse with respect to the computed ideal value. A survey of possible effects is offered, indicating widely different flame structures. A good understanding of the relevant burning phenomena opens the way to improved system performance by reducing combustion and gasdynamic expansion losses.
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ballistic characterization of alh 3 based propellants for solid and hybrid Rocket Propulsion
45th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit, 2009Co-Authors: Luigi T Deluca, Charles Kappenstein, L Rossettini, Volker WeiserAbstract:Experimental analyses of laboratory-type composite solid Rocket propellants and hybrid solid fuels based on �-AlH3 (alane) are presented. Chemical and physical properties of this peculiar energetic ingredient are discussed, ballistic properties experimentally evaluated under a variety of configurations, and flame structures compared with the corresponding aluminized propellants. The obtained results overall disclose a competitive performance of alane-based propellants with respect to the aluminized formulations and encourage its use in both solid and hybrid Rocket Propulsion for space exploration.
V M Soundalgekar - One of the best experts on this subject based on the ideXlab platform.
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radiation effects on free convection flow past a semi infinite vertical plate with mass transfer
Chemical Engineering Journal, 2001Co-Authors: Ali J Chamkha, Harmindar S Takhar, V M SoundalgekarAbstract:Laminar free convection flow of air past a semi-infinite vertical plate in the presence of chemical species concentration and thermal radiation effects is studied. This type of problem finds application in many technological and engineering fields such as Rocket Propulsion systems, spacecraft re-entry aerothermodynamics, cosmical flight aerodynamics, plasma physics, glass production and furnace engineering. The governing boundary-layer equations for this problem are reduced to a non-similar form and are solved numerically by an implicit finite-difference technique. Representative velocity, temperature and concentration profiles are shown graphically and the numerical values of the wall slopes of the velocity, temperature and concentration profiles (which are related to the dimensionless skin-friction coefficient, wall heat transfer and the Sherwood number, respectively) are also shown graphically. The effects of the radiation parameter, buoyancy ratio, Schmidt number and the dimensionless distance from the leading edge of the plate on the numerical solutions are presented and discussed.
Pratim Kumar - One of the best experts on this subject based on the ideXlab platform.
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an overview on properties thermal decomposition and combustion behavior of adn and adn based solid propellants
Defence Technology, 2018Co-Authors: Pratim KumarAbstract:Abstract Ammonium dinitramide [NH4N(NO2)2, ADN] is considered as a possible replacement for ammonium perchlorate (AP) in nearly all kind of solid Rocket Propulsions in the coming future. The reason to use ADN instead of AP in solid Rocket Propulsion is because of its harmless combustion products, along with its capacity to generate high specific impulse (Isp). ADN is fairly a new member in the solid oxidizer community and is considered under green energetic material (GEM). Application and feasible utilization of ADN as an oxidizer for composite solid propellants (CSP's) requires complete knowledge of its thermal decomposition processes along with its combustion behavior. A detailed overview on the physical and chemical properties, thermal decomposition, and combustion behavior of ADN and ADN based propellants has been discussed in this paper. Catalytic effect on thermal decomposition, combustion wave structure, and burning rate of ADN is also discussed.
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An overview on properties, thermal decomposition, and combustion behavior of ADN and ADN based solid propellants
Elsevier, 2018Co-Authors: Pratim KumarAbstract:Ammonium dinitramide [NH4N(NO2)2, ADN] is considered as a possible replacement for ammonium perchlorate (AP) in nearly all kind of solid Rocket Propulsions in the coming future. The reason to use ADN instead of AP in solid Rocket Propulsion is because of its harmless combustion products, along with its capacity to generate high specific impulse (Isp). ADN is fairly a new member in the solid oxidizer community and is considered under green energetic material (GEM). Application and feasible utilization of ADN as an oxidizer for composite solid propellants (CSP's) requires complete knowledge of its thermal decomposition processes along with its combustion behavior. A detailed overview on the physical and chemical properties, thermal decomposition, and combustion behavior of ADN and ADN based propellants has been discussed in this paper. Catalytic effect on thermal decomposition, combustion wave structure, and burning rate of ADN is also discussed. Keywords: ADN, Green oxidizer, Green propellant, Thermal decomposition, Combustio
Lowrey N. M. - One of the best experts on this subject based on the ideXlab platform.
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Replacement of HCFC-225 Solvent for Cleaning NASA Propulsion Oxygen Systems
2015Co-Authors: Mitchell M. A., Lowrey N. M.Abstract:Since the 1990's, when the Class I Ozone Depleting Substance (ODS) chlorofluorocarbon113 (CFC113) was banned, NASA's Rocket Propulsion test facilities at Marshall Space Flight Center (MSFC) and Stennis Space Center (SSC) have relied upon hydrochlorofluorocarbon225 (HCFC225) to safely clean and verify the cleanliness of large scale Propulsion oxygen systems. Effective January 1, 2015, the production, import, export, and new use of HCFC225, a Class II ODS, was prohibited by the Clean Air Act. In 2012 through 2014, leveraging resources from both the NASA Rocket Propulsion Test Program and the Defense Logistics Agency Aviation Hazardous Minimization and Green Products Branch, test labs at MSFC, SSC, and Johnson Space Center's White Sands Test Facility (WSTF) collaborated to seek out, test, and qualify a replacement for HCFC225 that is both an effective cleaner and safe for use with oxygen systems. Candidate solvents were selected and a test plan was developed following the guidelines of ASTM G127, Standard Guide for the Selection of Cleaning Agents for Oxygen Systems. Solvents were evaluated for materials compatibility, oxygen compatibility, cleaning effectiveness, and suitability for use in cleanliness verification and field cleaning operations. Two solvents were determined to be acceptable for cleaning oxygen systems and one was chosen for implementation at NASA's Rocket Propulsion test facilities. The test program and results are summarized. This project also demonstrated the benefits of crossagency collaboration in a time of limited resources
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Replacement of Hydrochlorofluorocarbon (HCFC) -225 Solvent for Cleaning and Verification Sampling of NASA Propulsion Oxygen Systems Hardware, Ground Support Equipment, and Associated Test Systems
2015Co-Authors: Juarez A., Lowrey N. M., Mitchell M. A., Farner B. R., Mcmillian J. H., Harper S. A., Burns H. D., Peralta S. F., Ross H. R.Abstract:Since the 1990's, NASA's Rocket Propulsion test facilities at Marshall Space Flight Center (MSFC) and Stennis Space Center (SSC) have used hydrochlorofluorocarbon-225 (HCFC-225), a Class II ozone-depleting substance, to safety clean and verify the cleanliness of large scale Propulsion oxygen systems and associated test facilities. In 2012 through 2014, test laboratories at MSFC, SSC, and Johnson Space Center-White Sands Test Facility collaborated to seek out, test, and qualify an environmentally preferred replacement for HCFC-225. Candidate solvents were selected, a test plan was developed, and the products were tested for materials compatibility, oxygen compatibility, cleaning effectiveness, and suitability for use in cleanliness verification and field cleaning operations. Honewell Soltice (TradeMark) Performance Fluid (trans-1-chloro-3,3, 3-trifluoropropene) was selected to replace HCFC-225 at NASA's MSFC and SSC Rocket Propulsion test facilities
