Impact and Friction Sensitivity of Energetic Materials：Methodical Evaluation of Technological Safety Features

Key methods developed and used in the USSR and in the Russian Federation to determine the impact and friction sensitivity of energetic materials and explosives have been discussed.Experimental methodologies and instruments that underlie the assessment of their production and handling safety have been described.Studies of a large number of compounds have revealed relationships between their sensitivity parameters and structure of individual compounds and compositions.The range of change of physical and chemical characteristics for the compounds we examined covers the entire region of their existence.Theoretical methodology and equations have been formulated to estimate the impact and friction sensitivity parameters of energetic materials and to evaluate the technological safety in use.The developed methodology is characterized by high-accuracy calculations and prediction of sensitivity parameters.

Correlation between Molecular Structure of Ferrocene Derivative and Impact Sensitivity of Fine-AP/Ferrocene Derivative Mixture

On the basis of investigation of molecular structure characteristics of model ferrocene derivatives, the correlation between stability and molecular structure of double-core ferrocene derivatives （DFDs） was studied. Then, the relation of stability of DFDs and impact sensitivity of fine-AP/DFD mixtures was investigated. The results showed that the DFDs with methylene bridge group were more stable than those with methylethylidene bridge group. The stability order of the five DFDs was DEFM〉EDFM≈BDFM〉GFP〉TBPF. The impact sensitivities of the fine-AP/DFD mixtures were in inverse proportion to the stabilities of the DFDs.

The effect of al particle size on thermal decomposition,mechanical strength and sensitivity of Al/ZrH_(2)/PTFE composite

To study the thermal decomposition of Al/Zr H_(2)/PTFE with different Al particle size as well as mechanical strength and impact sensitivity under medium and low strain rates,molding-vacuum sintering was adopted to prepare four groups of power materials and cylindrical specimens with different Al particle size.The active decomposition temperature of Zr H_(2) was obtained by TG-DSC,and the quasi-static mechanics/reaction characteristics as well as the impact sensitivity of the specimen were studied respectively by quasi-static compression and drop-hammer test.The results show that the yield strength of the material decreased with the increase of the Al particle size,while the compressive strength,failure strain and toughness increased first and then decreased,which reached the maximum values of 116.61 MPa,191%,and 119.9 MJ/m respectively when the Al particle size is 12-14 mm because of particle size grading.The specimens with the highest strength and toughness formed circumferential open cracks and reacted partly when pressed.Those with developmental cracks formed inside did not react.It is considered that fracture of specimens first triggered initial reaction between Al and PTFE to release an amount of heat.Then ZrH_(2) was activated and decomposed,and participated in subsequent reaction to generate Zr C.The impact sensitivity of the specimens decreased with the increase of Al particle size.

Properties and characterization of 1-methy-4,5-dinitroimidazole

X-ray diffraction （XRD）, differential scanning calorimeter （DSC） and impact sensitivity instrument were used to characterize the properties of 1-Methyl-4, 5-dinitroimidazole （MDNI）. Furthermore, specific heat capacity, thermal kinetic parameters, thermal decomposition reaction rate constant, critical explosion temperature and the drop height for impact initiation of MDNI were calculated and analyzed. The results show that MDNI is well-crystallized. The melting point of MDNI is about 74 ℃, and the specific heat capacity of MDNI is 9. 314 4 J/（g · K） and 10. 596 0 J/（g · K） when the temperature is 60 ℃ and 90 ℃, respectively. The apparent activation energy and pre-exponential factor of MDNI are calculated as 81.62 kJ/mol and 6. 78×10^7 s^-1 , respectively. The relationship between thermal decomposition reaction rate constant of MDNI and temperature is logk=7.83-4268.11/T. The critical temperature of MDNI thermal explosion is 234. 86℃. The drop height for impact initiation of MDNI is 95.3 cm.

An overview on importance, synthetic strategies and studies of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(HNIW)

2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(HNIW), commonly called as CL-20, is a high energy and high density material of keen interest to both commercial and scientific worlds due to its greater insensitivity(reduced sensitivity) along with a positive high heat of formation, which is due to the azanitro groups attached to the skeleton of HNIW and its highly strained cage structure. It plays a remarkable role in modification and replacement of most of the propellant(gun and rocket) preparations. In this report we present the comparative strategies involved in the syntheses of HNIW with respect to economical and environmental aspects. Various methods reported in the literature on the purification of the crude HNIW(α-HNIW) to obtain ε-form of HNIW(high dense/more potential) are consolidated. Understanding of the structure, morphology, energetics, thermal behavior and their modification to meet the applicability(decreased impact sensitivity) determines the industrial application of HNIW. A compilation of the available literature on the aforementioned characteristic properties for obtaining a value added ε-HNIW is discussed here. This overview also reports the literature available on newer forms of HNIW including derivatives and cocrystals,which increase the performance of HNIW.

Sonochemically assisted synthesis of nano HMX

Nanotechnology has played an influential role in improving the energetic content without subsiding the performance of high energy materials in the current era.In this work,HMX(octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine)nanoparticles were prepared by sonochemically assisted solvent-antisolvent spray technique focussing the reduction in its size so as to improve its energetic properties.In order to fabricate nano HMX various parameters such as different solvents and temperature were investigated.Sonication is one of the strategies recently explored in this regard;so time dependent study of sonication using probe sonicator was performed.It has been postulated that bubble formed during sonication when collapses generate high temperature and many nucleation sites which leads to the formation of uniform spherical particles with small size and fast transition phase.XRD studies depicted phase transformation from a toβas a result of sonication.The TEM images revealed that the rise in the sonication time resulted into decrease in the particle size from 300 to 10 nm.Differential scanning calorimetry(DSC)was employed to determine the heat release of the samples and enhancement in the heat release with the decrease in the particle size.A decrease in the spark sensitivity was observed from 2 J(regular HMX)to 50 mJ(nano HMX).

Influence of temperature on mechanical stimulation threshold of typical liquid propellant

In order to study the variation of temperature to mechanical stimulation threshold of typical liquid propellants(ADN-based HAN-based and nitromethane),the critical impact energy and critical friction of three propellants under different temperatures were studied by using BAM fall hammer impact sensitivity tester and BAM friction sensitivity tester.Experiments show that under 80℃,60℃,40℃and 20℃,the critical impact energy of HAN-based are 20 J,15 J,15 J,15 J;the critical impact energy of nitromethane are 2 J,2 J,2 J,2 J;and the critical impact energy of ADN-based are<1 J,3 J,7.5 J,15 J.It reveals that HAN-based propellant has the highest critical impact energy,while nitromethane propellant has the lowest critical impact energy.ADN-based propellant has a notable decrease on its critical impact energy with temperature decreasing,indicating that temperature has a significant effect on impact sensitivity of ADN-based propellant.The critical friction of three samples are all higher than 360 N at 80℃,60℃,40℃and 20℃,which shows that the samples are not sensitive to friction,and temperature has no significant effect on the critical friction of three samples.The mechanical stimulations that may be encountered during the production and use of liquid propellants are analyzed,which takes certain working conditions and the temperature coupling effect into consideration,thereby providing support for safety management of liquid propellants during production and storage process.

Theoretical Calculation about the High Energy Density Molecules of Nitrate Ester Substitution Derivatives of Prismane

The nitrate ester substitution derivatives of prismane were studied at the B3LYP/6-311G＊＊ level. The sublimation enthalpies and heats of formation in gas phase and solid state were calculated. The detonation performances were also predicted by using the famous Kamlet-Jacbos equation. Our calculated results show that introducing nitrate ester group into prismane is helpful to enhance its detonation properties. Stabilities were evaluated through the bond dissociation energies, bond order, characteristic heights（H50） and band gap calculations. The trigger bonds in the pyrolysis process of prismane derivatives were confirmed as O–ON2 bond. The BDEs of all compounds were large, so these prismane derivatives have excellent stability consistent with the results of H50 and band gap.

Theoretical Studies on Two Possible Conformers of TNDAIW at Hartree-Fock Level

Tetranitrodiazidoacetylhexaazaisowurtzitane (TNDAIW) is a novel polyazapolycyclic caged polyazidonitramine explosive first synthesized in our laboratory. Two possible conformers of TNDAIW with C_s symmetry were fully optimized using the HF/6-31G(d) level of theory. TNDAIW with the optimized geometries probably exists, and is predicted to be more stable than epsilon-hexanitrohexaazoisowurtzitane (epsilon-CL-20) based on the lengths of N-N, C-C and C-N bonds. The impact and shock sensitivities are lower for the possible conformers of TNDAIW than those for epsilon-CL-20. TNDAIW with the optimized possible conformers is estimated to be a promising novel high energy density explosive.

Theoretical Study of Energetic Complexes （Ⅲ）： Bis-（5-nitro-2Htetrazolato-N2）tetraammine Cobalt（Ⅲ） Perchlorate （BNCP） and Its Transition Metal （Ni/Fe/Cu/Zn） Perchlorate Analogues

The geometric conformation and electronic structure of bis-（5-nitro-2H-tetrazolato-N2）tetraammine cobalt（Ⅲ） perchlorate and its Ni/Fe/Cu/Zn analogues are studied under the TPSS （Tao-Perdew-Staroverov-Scuseria） levels of density functional theory in order to throw light on the relationship between their energy gaps and impact sensitivity While the perchlorate ions are coordinated with the copper cation, which is different from the other four compounds NBO （Natural bond orbital） analyses indicated that the metal-ligand interaction in the Co complex is covalent, while the others are ionic. The analysis of the electrostatic potential demonstrated that the O atoms from the nitro-tetrazole ring and perchlorate were primarily negative, while the other atoms were positive. The study was also conducted to gain a better understanding of the correlation of the energy gap and impact sensitivity.

Fifty Years of Water Sensitive Urban Design, Salisbury, South Australia

Australia has developed extensive policies and guidelines for the management of its water. The City of Salisbury, located within metropolitan Adelaide, South Australia, developed rapidly through urbanisation from the 1970s. Water sensitive urban design principles were adopted to maximise the use of the increased rim-off generated by urbanisation and ameliorate flood risk. Managed aquifer recharge was introduced for storing remediated low-salinity stormwater by aquifer storage and recovery （ASR） in a brackish aquiter for subsequent lrngatlon. Ibis paper outlines now a municipal government has progressively adopted principles of Water Sensitive Urban Design during its development within a framework of evolving national water policies. Salisbury＇s success with stormwater harvesting led to the formation of a pioneering w aterbusiness that includes linking projects from nine sites to provide a non-potable supply of 5 ×10^6 m^3 year. These installations hosted a number of applied research projects addressing well configuration, water quality, reliability and economics and facilitated the evaluation of its system as a potential potable water source. The evaluation showed that while untreated stonnwater contained contaminants, subsurface storage and end-use controls were sufficient to make recovered water sale for public open space irrigation, and with chlorination acceptable lbr third pipe supplies. Drinking water quality could be achieved by adding microfiltration, disinfection with UV and chlorination. The costs that would need to be expended to achieve drinking water safety standards were found to be considerably less than the cost of establishing dual pipe distribution systems. The full cost of supply was determined to be AUD$1.57 m ＂ for non-potable water for pubhc open space lrngatlon much cheaper than mares water, AUD $3.45 m at that time. Producing and storing potable water was found to cost AUDS1.96 to $2.24 m .