This paper describes the power conditioning scheme for a contactless coilgun called the Linear Induction Launcher (LIL) as an open-loop integrated system. The barrel of the LIL consists of a linear array of coils carrying polyphase currents. These create an electromagnetic wave packet which moves with increasing velocity from breech to muzzle, smoothly accelerating a conductive sleeve which carries a set of azimuthal currents sinusoidally distributed along its length, and which encloses the projectile payload. The power conditioner provides high utilization of energy by transferring energy from capacitor to capacitor simultaneously with the projectile movement. A modular construction of the barrel is described together with laboratory results obtained with a breadboard model of the power conditioner circuit.

A railgun simulator has been constructed at UTA that is capable of producing a high current, moving plasma armature. The railgun simulator may be fired tens of times per day in order to provide large amounts of data on plasma armature parameters. The high repetition rate allows for the development of diagnostic techniques that may be applied to railguns. The device at UTA has been used to test and develop techniques for acquiring and interpreting optical data, to measure the amount of optical laser transmission through the plasma, and to measure the plasma velocity. A new experimental chamber has been constructed that will greatly enhance the flexibility of the device, and allow for further plasma studies and diagnostics development.

An alternative to satellite-based kinetic energy weapons for intercepting ballistic missiles early in their trajectories is the use of earth-based hyper-velocity rockets. Simple calculations show that with existing solid-propellant technology, rockets can be accelerated to more than twice circular-orbit speeds with mass ratios of several thousand to one. For intercept distances ranging from 2000 to 5000 miles this translates into flight times of between 4 and 10 minutes. This permits interception of hostile ballistic missiles during their ascent trajectory when vulnerability remains high. The use of miniature guided warheads in the defensive weapon reduces the interceptor takeoff weight to within reasonable bounds. Parameters to be optimized include the mass ratios and thrusting time for each stage, the coasting time between powered stages, and the parameters used to represent the time history of angle of attack. A quasi-Newton minimization algorithm is utilized with penalty functions to implement the terminal constraints, as well as any other constraints. The necessary gradients are computed numerically using finite differences. The multiple stage trajectories are calculated many thousands of times faster than real time using an AD 100 multiprocessor computer. A VAX host computer implements the optimization algorithm and inputs new parameters to the multiprocessor for each successive trajectory run. In this way the total required time for an overall trajectory optimization consisting of several thousand trajectories is reduced from several hours to several minutes.

Nitramine ligands have very rarely been employed in metal complex chemistry. This paper describes several new metal-nitraminato compounds of Cu(II), Ni(II) and Pd(II) and their crystal structures. Some of the compounds are potentially interesting as nitramine burn-rate catalysts. To this end, gas product speciation studies were conducted on the compounds under conditions of high heating rate thermolysis. Selected results are described.

Nine diesters of cubane 1,4-dicarboxylic acid were synthesized and evaluated as advanced propellant plasticizers. Three energetic cubyl ammonium salts of amino and 1,4-diamino cubane were synthesized as models for more highly substituted cubyl ammonium salt oxidizers. Methyl carbamates of amino cubanes have been successfully nitrated with 100% HNO3/(CH3C0)20. These nitrated carbamates are precursors to unsubstituted nitramino cubanes.

The objective of this research is to develop new methods for the functionalization of the cubane nucleus and to synthesize energetic cubanes for use as energetic propellants and explosives. Recent achievements in this program include a high yield synthesis of dinitrocubane, a new preparation of cubane-1,3-diacid, and synthesises of cubane-1,2,4,7- tetraacid, cubane-1,2,4,7-tetraisocyanate, 1,2,4,7-tetraaminocubane tetrahydrochloride, and a propellanocubane. We have developed new methods of cubane functionalization, and the first preparation of energetic polynitrocubanes; cubane-1,2,4,7-tetrakis(B,B,B-fluorodinitroethylester), cubane-1,4-bis(B,B,B-trinitroethylester), cubane-1,2,4,7- tetrakis(B,B,B-trinitroethylester), N,M-bis-1,4-(B,B,13-fluorodinitroethylamino)cubane, and N-nitro-N'-nitroso-bis-1,4-(B,B,B-fluorodinitroethylamino)cubane.

The hypervalent iodine oxidative decarboxylation of homocubyl and cubyl mono- and di-carboxylic acids is reported; the carboxylic acid is treated with PhI(OAc)2CC14-I2 under irradiation conditions and 80-90% of the derived iodo compound is obtained. Systematic functionalization of cubane is an important synthetic goal. The two main methods of cubane synthesis involve sequential Favorskii ring contractions to yield first a homocubyl carboxylic acid, and theh after a second Favorskii reaction, a 1,41,2 or 1,33 cubyl dicarboxylic acid. As a consequence of this synthetic procedure the carboxy group is a logical starting functionality for subsequent synthetic transformation in the cubyl ring system. The carboxy group has been converted ,into a nitro group in the synthesis of 1,4-dinitrocubane4 and halogenodecarboxylation has been effected.596 In a basically different approach Eaton et al., used ortho-lithiation of the der td carboxamide etc a site for ortho-iodination.7 Introduction of an iodo group onto the cubyl system is especially desirable because hypervalent iodine synthetic methodology may be employed in order to effect displacement reactions. This scheme has been successfully applied by Eaton et al.8 in tim cubyl system for R-IC12+ R-C1 R-I(OAC)2+ R-OAc where R=1- iodo-2-N,N-di-isopropylcarbox-amido-5-methylcubane.

The thermolysis at high heating rates of ethylenediamine dinitrate, hydroxylammonium nitrate (HAN) and a 50/50 by weight mixture of HAN and hydrazinium nitrate is described by using the rapid-scan infrared/thermal profiling technique. Considerable mechanistic detail about the thermal decomposition process can be obtained by this method that is not easily obtained otherwise.

Experimental determinations of new phase diagrams of molten salts are difficult, costly, and time consuming. To go around this problem, it is possible and necessary to use thermodynamics to predict the phase and temperature relations in almost any system under consideration, provided there is enough data available. After finding the areas of interest in each system in which trade-offs of physical and chemical properties can be made, one can again return to the experiment to verify the theory in a very short time. After checking the validity of our calculation method on two systems known from the literature, several new ternary and quaternary reciprocal systems were calculated. A continuous literature search for the basic thermodynamic data was the key to generate those systems. Several equations that help to estimate the missing data are given, and the importance of some particular data is emphasized. Contaminants, mainly water vapor (but also metal oxides, carbon dioxide and others), can have a profound effect on the properties of the salts. Some contaminants can be treated as reactive gases which interact with the molten salt solution. The theory, the references to experimental methods necessary, and the interpretation of interactions are the topics of the final part of the paper, and might constitute a contribution towards avoiding or reversing the contamination.

used hydroxylamine nitrate decomposes within a few minutes in the temperature range 130-140°C. Added ammonium ion is converted to N2, while hydrazinium ion is converted to HN3. Nitrous acid is an intermediate and its formation is rate-determining. A hygride transfer process is postulated. The reaction pathways have been elucidated by use of N tracers.

Currently, the selection of elements and operating conditions in the mixing of various materials in a co-rotating twin screw extruder is an art which requires previous experimental studies. In this report, we outline various experimental and theoretical tools developed to investigate the mixing process in a fully intermeshing co-rotating twin screw extruder. The thermo-mechanical history of mixing is simulated employing the finite element method. To verify the numerical findings, experimental techniques were developed to investigate the goodness of mixing of samples collected from a 50.8 mm, clam shell design, Baker-Perkins twin screw extruder.

High-internal-phase-volume emulsions of 75 volt 3/18/79 potassium iodide/sodium iodide/ urea model eutectic salt mixture in 83.5/16.5 Sartomer R-45HT hydroxy-terminated polybutadi-ene/Nujol mineral oil binder mixture were prepared at 60°C using water-in-oil emulsifiers and cured with isophorone diisocyanate or Desmodur N-100. The Nujol mineral oil enhanced the emulsification with a negligible reduction in the tensile properties of the cured elastomer. The average emulsion droplet sizes were ca. 200 nm initially, but increased slowly during curing to 500-1000 nm. The coalescence of the emulsion droplets followed the second-order dependence predicted by the von Smoluchowski diffusion-controlled flocculation; the rate constants were 1.05x10-18 and 9.58x10-18 cc/droplet-sec for dirnethyldioctadecylammonium bromide and Span 85 sorbitan trioleate, respectively. The isophorone diisocyanate reacted with emulsifiers containing primary hydroxyl or amine groups, to give unstable emulsions or no emulsions at all. Dimethyldioctadecylammonium bromide with no primary hydroxyl or amine groups, however, did not react with isocyanates and gave stable emulsions. The reaction of the R-45HT hydroxy-terminated polybutadiene with isophorone diisocyanate followed the expec-ted second-order kinetics with a rate constant of 3.42x10-4 liters/mole-sec at 60°C. The tensile properties of the cured elastomers and emulsions generally increased with increasing NCO/OH ratio up to 1.6/1.0. With increasing volume fraction of dispersed phase, the maximum stress (tensile strength) decreased, the maximum strain (percent elongation) increased, and the initial modulus (tensile modulus) decreased, in contrast to the behavior of conventional filled polymer systems; however, the maximum stresses were in accord with theoretical values for a filled polymer in which the filler particles bear no load, the initial moduli were in accord with the predictions of an isostrain model, and the maximum strain increased with in-creasing volume fraction of dispersed phase; these unusual variations, which were attributed to the liquid nature of the emulsion droplets, were used to estimate the elastomer proper-ties required to give the desired properties: 60-100 psi maximum stress, 80-150% maximum strain, and 500-2000 psi initial modulus for an 88/12 eutectic salt/crosslinked polybutadi-ene composite containing 20% aluminum particles. The addition of 20% aluminum particles gave a modest improvement in tensile properties, and the addition of 2.5% or 3.5% submicroscopic carbon black particles gave a greater improvement; however, the tensile properties were still slightly short of the desired properties.

Alkyl 4-[()-alkoxybenzoyi)oxy]benzoates(with Cl-Cloalkyl and alkoxy groups) are monotropic compounds which melt directly to isotropic liquids. Twin liquid crystalline compounds, TLCC's of [alkoxybenzoyl)oxy]benzoic acid have been synthesized. The TLCC with methoxy end groups and trioxyethylene spacer is weakly mesogenic, but replacement of the methoxy with an n-butoxy end group results in a smectic mesophase. With the decamethylene spacer, the TLCC with a methoxy end group shows a nematic mesophase, whereas the compound with n-butoxy end groups exhibits both smectic and nematic mesophases. The latter has much higher ordered liquid crystalline states than the former. The polymeric TLCP's with n-butoxy end groups and Mn=650 poly(THF) and Mn=725 poly(propylene oxide) spacers display weak liquid crystal-line order with only one mesophase transition. Decreasing the M of the poly(propylene oxide) spacer to 425 resulted in much stronger liquid crystallinenorder, exhibiting both smectic and nematic phases. It is suggested the microphase separation due to dissimilar solubility parameters can be an important contributing factor toward mesophase formation. Using this approach, TLCP's having energetic poly(hexafluoropentanediol formal) soft seg-ments have synthesized.

The basic function of any space propulsion system is to produce as high a propellant exhaust velocity as is possible for that technology. Therefore, in seeking to improve the performance of any propulsion system, a measurement of the radial distribution of the axial velocity component at the engine exit plane is invaluable. A simultaneous measurement of the radial distribution of the atom temperature will also provide insight into engine operation. This paper describes a non-intrusive technique for obtaining these measurements and presents some preliminary results of a radial survey in an arcjet engine plume. The technique involves a measurement of the doppler shift of an optically thin line, resulting from recombination and relaxation processes in the high Mach number stream, for velocity determination. The atom temperature can be calculated from a measurement of doppler broadened line widths.

Detailed experimental investigations were conducted to define the operating characteristics of a 30-kW type, arcjet engine with a contoured nozzle. The experiments were conducted in a fully instrumented facility with the engine mounted on a thrust stand. Engine performance was mapped over a power range of 10.6 to 23.0 kW with a mass flow range of 0.175 to 0.350 g/s. The data is presented in graphical form with the relationships between arc potential, arc current, power, thrust, specific impulse and thrust efficiency presented. This paper provides the first detailed accounting of arcjet operation with a contoured nozzle. Further theoretical and experimental work needs to be done to fully explain many of the features exhibited by the data.

The anode and cathode of a 30-kW class arcjet engine have been sectioned and analyzed. This arcjet was operated for a total time of 573 hours at power levels between 25 and 30 kW with ammonia at flow rates of 0.25 and 0.27 gm/s. The accumulated run time was sufficient to clearly establish erosion patterns and their causes. The type of electron emission from various parts of the cathode surface was made clear by Scanning Electron Microscope analysis. A Scanning Electron Microscope was used to study recrystallization on the hot anode surface. These electrodes were made of 2% thoriated tungsten and the surface thorium content and grad-ient perpendicular to the surfaces was determined by quantitative microprobe analysis. The results of this material analysis on the electrodes and recommendations for improving electrode operational life time are presented.

Preliminary experimental investigations were conducted to evaluate the effects of a modified cathode shape on ammonia arcjet engine performance. The experiments were conducted with a contoured nozzle arcjet in a fully-instrumented facility which included a thrust stand. The modified cathode tip had a reduced diameter and more acute conical tip with respect to the baseline cathode design. A uniform 15% decrease in arc voltage was demonstrated over a mass flow range of 0.175 to 0.350 g/s. A 4% improvement in thrust efficiency was noted at 22.0 kW. Plans for future cathode testing are discussed with the aim of developing a long-life, high-performance arcjet cathode.

The objective of our research is to synthesize energetic polyether binders with the ability to undergo reversible physical crosslinking at temperatures compatible with high energy propellant ingredients. Commercially available thermoplastic elastomers fail to meet our criteria because of excessively high processing temperatures and melt viscosity, high modulus and low stress/strain capability. It was proposed to synthesize ABA type block polymers with the A blocks being polymers able to form crystalline structure (as opposed to glasses) having a sharp melting point of 85-95°C. This would enable phase miscibility in the melt, thus lowering melt viscosity, and reduce creep close to the melting point. ABA structures were chosen over (AB)n, enabling low molecular weight polymers to be synthesized, again lowering viscosity. In order to successfully achieve our objectives, it was necessary to synthesize precise polymer structures with little deviation from the required structure. After evaluating blocklinking techniques, we decided to employ living cationic polymerization with systematic monomer addition. To this end, we have examined numerous catalysts and co-catalysts. Our research at this time is centered on bis cumyl chloride/silver antimony hexafluoride in which we see promising results. The effects of polymerization temperature, catalyst formation, catalyst concentration, rate of monomer addition and monomer concentration were determined with respect to molecular weight control and structure. Polymer workup and purification, a problem in our initial studies, has been resolved. We have now synthesized polymers varying in molecular structure and correlated the resulting physical properties to structural changes. The effect of structure and molecular weight on melt viscosity and morphology is now being examined.