Lead salt of 2, 4, n-trinitroanilinoacetic acid - an energetic ballistic modifier for double base propellants

Abstract

Lead Salt of 2,4,N-trinitroanilinoacetic acid has been evaluated as ballistic modifier in composite modified double base matrix. Burn rate measurements showed a plateau effect between 3.43 — 8.82 MPa. The salt-containing propellant composition showed a synergistic effect on decomposition of propellants as evidenced by a reduction in differential thermal analysis exotherm peak temperature. Effect of magnesium oxide-lead salt combination on burn rate of propellant formulation was also evaluated. The combination increased the burn rate at 6.86 — 8.82 MPa and decreased at 10.78 MPa. The salt has been prepared by double decomposition of lead nitrate with sodium salt of 2,4,N-trinitroanilinoacetic acid, which in turn is prepared from glycine and 2,4 - dinitrochlorobenzene. The lead salt decomposes at 187°C as shown by differential thermal analysis exotherm. Calorimetric value (+3.14 MJ/kg) of the salt has been calculated. The salt exhibits an impact sensitivity height (h₅₀) of 97.5 cm and friction sensitivity of >36 kg.     

Dendtritic Azido Ester: A Potential Energetic Additive for High Energy Material (HEM) Formulations

A second-generation [G-2] terminally azido functionalized dendritic ester has been synthesized from a commercially available dendritic polyol BOLTORN^® H20. Structural features were confirmed by IR, ¹H NMR, and elemental analysis. The differential scanning calorimetry (DSC) analysis shows an acceptable thermal stability for practical applications in high energy material formulations.     

The prevalence of Vibrio spp. in drinking water and environmental samples in Vellore South India

We compared the seroprevalence of both Toxoplasma gondii and Trichinella spiralis in finishing pigs raised in different production systems in North Carolina, USA. Farms were either finishing sites using all-in/all-out management of buildings in multiple-site systems (14 farms) or farrow-to-finish systems using continuous-flow management of finishing barns or outdoor accommodation 14 farms). The two groups of herds differed with respect to several management variables. A total of 13 of 2238 samples (0.58%) were positive for antibodies to Toxoplasma gondii using the modified agglutination test. Of these, 12 were from 63 pigs sampled on a farm where finishing pigs were kept on pasture. Only one of 1752 (0.057%) samples from pigs kept in total confinement systems was seropositive. Only one pig of 2183 (0.046%) tested positive by ELISA for antibodies against T. spiralis. In this region, management practices in modern production systems appear to be adequate to virtually eliminate the risk of infection of finishing pigs with both T. gondii and T. spiralis.     

A photocrosslinkable melt processible acrylonitrile terpolymer as carbon fiber precursor

A novel photocrosslinkable and melt processible terpolymer precursor for carbon fiber has been successfully synthesized and characterized. The terpolymer was synthesized by an efficient emulsion polymerization route and has a typical composition of acrylonitrile/methyl acrylate/acryloyl benzophenone in the mole ratio, 85/14/1. It has been characterized by FTIR, NMR, intrinsic viscosity and GPC molecular weights. The composition of the monomer repeat units in the terpolymer was determined by NMR, and was almost identical to the molar feed ratios of the monomers used for polymerization. The T_g of the terpolymers, were somewhat a function of molecular weight, but were in the range 77-91 °C. The fibers were spun from the terpolymer melts unlike the conventional solution spinning method. The terpolymers when stabilized with boric acid afforded a stable melt for about 30 min at 200-220 °C, which was empirically found to be sufficiently long to spin fibers. The terpolymer with the highest molecular weight (M_n, ∼48,000) was not melt processible, apparently because the melt viscosity was very high and the terpolymer degraded fast. However, terpolymers, which had an intrinsic viscosity <0.6 dL/g (NMP, 25 °C) were invariably melt processible. The initial carbon fibers produced from these terpolymer fibers upon complete carbonization exhibited good mechanical properties for proposed automotive applications; the tensile strength of the best fibers generated thus far was in the range 450-700 MPa with a strain to failure of ∼0.4%. The diameter of the carbon fibers was of the order of 7 μm.     

Characterization and catalytic investigation of Fe-ZSM5 for urea-SCR

Fe-ZSM5 was prepared with high iron content by solid-state ion exchange and characterized by ICP-AES, BET surface measurements, TEM, UV–vis, EPR and DRIFT spectroscopy as well as supplementing catalytic tests in order to clear up its functionality in urea-SCR. Due to the over-exchange with iron small Fe₂O₃ particles were formed, identified by UV–vis, EPR and TEM measurements, which were proved to be not active for the SCR reaction. However, the oxidation of NO to NO₂ over Fe³⁺ ions in the catalyst was realized to be a pre-requisite for the SCR reaction and the rate-determining step. DRIFT investigations under SCR conditions showed adsorbates on Fe²⁺ up to 300 °C. The high SCR activity above 300 °C can be explained by the faster reoxidation of Fe²⁺ to Fe³⁺ sites at high temperatures. The observed inhibition of the SCR reaction by excess ammonia at low and intermediate temperatures can be explained in this context by the reducing properties of ammonia converting Fe³⁺ to Fe²⁺ or by preventing the reoxidation of Fe²⁺.     

Nonaqueous Cold Extrusion as a Route for Yttrium Barium Copper Oxide Wires

Yttrium barium copper oxide (YBCO) superconducting wires of diameter 0.2 to 1 mm in the form of spirals up to 50 cm long were made by a novel nonaqueous cold extrusion technique. Finely ground YBCO powder having a set particle size distribution was intimately mixed with a polypropylene compound and extruded manually into wires which were heat-treated at controlled rates followed by oxygen annealing at 940°C for 10 h. These wires are superconducting with a T _c of 89.5 K, the XRD pattern exhibiting an orthorhombic single phase. Current density at zero field was measured to be 223 A/cm². The surface morphology of the extruded wires and microstructure of the polished cross section of the sintered wires are also presented.     

Overview of the DOE hydrogen safety,codes and standards program,part 3: Advances in research and development to enhance the scientific basis for hydrogen regulations,codes and standards

Hydrogen fuels are being deployed around the world as an alternative to traditional petrol and battery technologies. As with all fuels, regulations, codes and standards are a necessary component of the safe deployment of hydrogen technologies. There has been a focused effort in the international hydrogen community to develop codes and standards based on strong scientific principles to accommodate the relatively rapid deployment of hydrogen-energy systems. The need for science-based codes and standards has revealed the need to advance our scientific understanding of hydrogen in engineering environments. This brief review describes research and development activities with emphasis on scientific advances that have aided the advancement of hydrogen regulations, codes and standards for hydrogen technologies in four key areas: (1) the physics of high-pressure hydrogen releases (called hydrogen behavior); (2) quantitative risk assessment; (3) hydrogen compatibility of materials; and (4) hydrogen fuel quality.     

Assessing manufacturing strategy definitions utilising text-mining

The variations in Manufacturing Strategy (MS) definitions create confusion and lead to lack of shared understanding between academic researchers and practitioners on its scope. The purpose of this study is to provide an empirical analysis of the paradox in the difference between academic and industry definitions of MS. Natural Language Processing (NLP) based text mining is used to extract primary elements from the various academic, and industry definitions of MS. Co-word and Principal Component Analysis (PCA) provide empirical support for the grouping into nine primary elements. We posit from the terms evolution analysis that there is a stasis currently faced in academic literature towards MS definition while the industry with its emphasis on ‘context’ has been dynamic. We believe that the proposed approach and results of the present empirical analysis can contribute to overcoming the current challenges to MS design and deployment – imprecise definition leading to its inadequate operationalisation.     

Limited grain growth and chemical ordering during high-temperature sintering of PtNiCo nanoparticle aggregates

High-temperature sintering of ternary Pt(x)Ni(100-x-y)Co(y) (x?=?28-44%, y?=?40-54%) nanoparticles of interest in catalysis was studied in situ and in real-time with synchrotron-based x-ray diffraction. For the first time we were able to experimentally capture the early stage of the thermal treatment, and found the nanoparticles to undergo an unusual two-step coalescence process that involves transient growth and restructuring of the nanoparticles. The coalescence process is accompanied by lattice contraction, likely due to composition evolution towards a random alloy. In the late stage of sintering, evidence was found for self-limited grain growth and L1(0) chemical ordering. The order-disorder transition temperature was found to be around 800?°C in all four ternary alloy compositions studied. Fitting of the experimental data with the model for grain growth with size-dependent impediment leads to an activation energy for mass transport of about 100?kJ?mol(-1), and may be used as a predictive tool to estimate particle size as a function of heat treatment temperature and duration.     

On weak relative degree and the McGehee transformation

Points where jumps in relative degree occur are presented as singularities in the vector field of the internal dynamics of systems that are candidates for input-output linearization via nonlinear feedback. For a certain class of vector fields, it is shown that the point at which the relative degree is weak can be transformed to a saddle equilibrium point at the origin