Excellent detonation performances and low sensitivity are prerequisites for the deployment of energetic materials.Exploring the underlying factors that affect impact sensitivity and detonation performances as well as ...Excellent detonation performances and low sensitivity are prerequisites for the deployment of energetic materials.Exploring the underlying factors that affect impact sensitivity and detonation performances as well as exploring how to obtain materials with desired properties remains a long-term challenge.Machine learning with its ability to solve complex tasks and perform robust data processing can reveal the relationship between performance and descriptive indicators,potentially accelerating the development process of energetic materials.In this background,impact sensitivity,detonation performances,and 28 physicochemical parameters for 222 energetic materials from density functional theory calculations and published literature were sorted out.Four machine learning algorithms were employed to predict various properties of energetic materials,including impact sensitivity,detonation velocity,detonation pressure,and Gurney energy.Analysis of Pearson coefficients and feature importance showed that the heat of explosion,oxygen balance,decomposition products,and HOMO energy levels have a strong correlation with the impact sensitivity of energetic materials.Oxygen balance,decomposition products,and density have a strong correlation with detonation performances.Utilizing impact sensitivity of 2,3,4-trinitrotoluene and the detonation performances of 2,4,6-trinitrobenzene-1,3,5-triamine as the benchmark,the analysis of feature importance rankings and statistical data revealed the optimal range of key features balancing impact sensitivity and detonation performances:oxygen balance values should be between-40%and-30%,density should range from 1.66 to 1.72 g/cm^(3),HOMO energy levels should be between-6.34 and-6.31 eV,and lipophilicity should be between-1.0 and 0.1,4.49 and 5.59.These findings not only offer important insights into the impact sensitivity and detonation performances of energetic materials,but also provide a theoretical guidance paradigm for the design and development of new energetic materials with optimal detonation performances and reduced sensitivity.展开更多
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 instru...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.展开更多
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....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.展开更多
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 pr...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.展开更多
Composite microcrystals of the nitramines(NAs)viz.,RDX,HMX,BCHMX,and CL-20 with electrically conductive polyaniline(PANi)are a charge transfer complexes in coagglomerated composite crystals(CACs).The activation energi...Composite microcrystals of the nitramines(NAs)viz.,RDX,HMX,BCHMX,and CL-20 with electrically conductive polyaniline(PANi)are a charge transfer complexes in coagglomerated composite crystals(CACs).The activation energies of thermolysis,E_(a),of the pure NAs and their PANi-CACs were determined using the Kissinger method,and decomposition processes are discussed.Except for the RDX/PANi CACs,all the other CACs show higher E_(a) values for decomposition compared to their pure NA counterparts.For all CACs,relationships are specified between the E_(a) values,on the one hand,and the squares of the detonation velocities,enthalpies of formation,spark energy and impact sensitivities,on the other.The relationships between their low-temperature heats of decomposition,ΔH,from DSC,and their enthalpy of formation,logarithm of impact sensitivity,electric spark energy,as well as detonation energy,are described.The PANi favorably influences the density of the corresponding CACs;surprisingly close linear correlations were found,and explained,between these densities and the E_(a) values.This presence of PANi strongly increased the electrical spark sensitivity of the CACs in comparison to the base NAs.Based on the results obtained,it can be noted in particular the exceptional desensitization of HMX to impact and the increased sensitivity to electrical spark by coating its crystals with polyaniline.展开更多
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 ca...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.展开更多
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 insen...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.展开更多
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-tetr...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).展开更多
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 propella...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.展开更多
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 perform...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.展开更多
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 ...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.展开更多
Enhancing the safety of high-energy explosives(EMs)is crucial for the secure handling of energetic materials during storage,transportation,and use.Compositing multiple energetic materials effectively enhances the inse...Enhancing the safety of high-energy explosives(EMs)is crucial for the secure handling of energetic materials during storage,transportation,and use.Compositing multiple energetic materials effectively enhances the insensitivity of explosives.This study used N,N-dimethylformamide(DMF)as a solvent in the rotary evaporation method to prepare 1,1-diamino-2,2-dinitroethene/1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane(FOX-7/HMX)composite crystals.By varying the molar ratios of FOX-7 and HMX,this study investigated their effects on the morphology of the composite crystals,and the formation mechanism of the composite crystal was analyzed.The study characterized and tested the crystal structure,thermal decomposition,cook-off performance,and impact sensitivity of the composite crystal.The results indicate that at a 5:5 M ratio of FOX-7 to HMX,the compound degree is 90.79%,and FOX-7 exhibits uniform adhering to the surface of the HMX crystal.FT-IR and XRD patterns analyses revealed shifts in the absorption peak of the composite crystal and the characteristic peak of the XRD curve.FOX-7 crystals were embedded on the surface of HMX crystals,forming a co-crystal layer and altering the crystal structure.Differential scanning calorimetry tests demonstrate that the thermal decomposition temperature of FOX-7/HMX composite crystals is 1.77℃ higher than the raw FOX-7,and during the cook-off test,the composite crystal reaction level is combustion,accompanied by an increase in characteristic drop height to 62.6 cm,indicating improved thermal stability and impact safety.展开更多
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） ...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.展开更多
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 ...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 .展开更多
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2682024GF019)。
文摘Excellent detonation performances and low sensitivity are prerequisites for the deployment of energetic materials.Exploring the underlying factors that affect impact sensitivity and detonation performances as well as exploring how to obtain materials with desired properties remains a long-term challenge.Machine learning with its ability to solve complex tasks and perform robust data processing can reveal the relationship between performance and descriptive indicators,potentially accelerating the development process of energetic materials.In this background,impact sensitivity,detonation performances,and 28 physicochemical parameters for 222 energetic materials from density functional theory calculations and published literature were sorted out.Four machine learning algorithms were employed to predict various properties of energetic materials,including impact sensitivity,detonation velocity,detonation pressure,and Gurney energy.Analysis of Pearson coefficients and feature importance showed that the heat of explosion,oxygen balance,decomposition products,and HOMO energy levels have a strong correlation with the impact sensitivity of energetic materials.Oxygen balance,decomposition products,and density have a strong correlation with detonation performances.Utilizing impact sensitivity of 2,3,4-trinitrotoluene and the detonation performances of 2,4,6-trinitrobenzene-1,3,5-triamine as the benchmark,the analysis of feature importance rankings and statistical data revealed the optimal range of key features balancing impact sensitivity and detonation performances:oxygen balance values should be between-40%and-30%,density should range from 1.66 to 1.72 g/cm^(3),HOMO energy levels should be between-6.34 and-6.31 eV,and lipophilicity should be between-1.0 and 0.1,4.49 and 5.59.These findings not only offer important insights into the impact sensitivity and detonation performances of energetic materials,but also provide a theoretical guidance paradigm for the design and development of new energetic materials with optimal detonation performances and reduced sensitivity.
文摘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.
基金We are grateful for the financial support from the joint fund of the National Natural Science Foundation Committee of China Academy of Engineering Physics （NSAF） （No. U1230102）.
文摘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.
基金financial support from the National Natural Science Foundation of China(General Program.Grant No.51673213)the National Natural Science Foundation of China(Youth Science Foundation.Grant No.51803235)。
文摘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.
基金funding from the Student Grant Project no.SGS_2022_003 of the Faculty of Chemical Technology at the University of Pardubice Czechia.
文摘Composite microcrystals of the nitramines(NAs)viz.,RDX,HMX,BCHMX,and CL-20 with electrically conductive polyaniline(PANi)are a charge transfer complexes in coagglomerated composite crystals(CACs).The activation energies of thermolysis,E_(a),of the pure NAs and their PANi-CACs were determined using the Kissinger method,and decomposition processes are discussed.Except for the RDX/PANi CACs,all the other CACs show higher E_(a) values for decomposition compared to their pure NA counterparts.For all CACs,relationships are specified between the E_(a) values,on the one hand,and the squares of the detonation velocities,enthalpies of formation,spark energy and impact sensitivities,on the other.The relationships between their low-temperature heats of decomposition,ΔH,from DSC,and their enthalpy of formation,logarithm of impact sensitivity,electric spark energy,as well as detonation energy,are described.The PANi favorably influences the density of the corresponding CACs;surprisingly close linear correlations were found,and explained,between these densities and the E_(a) values.This presence of PANi strongly increased the electrical spark sensitivity of the CACs in comparison to the base NAs.Based on the results obtained,it can be noted in particular the exceptional desensitization of HMX to impact and the increased sensitivity to electrical spark by coating its crystals with polyaniline.
文摘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.
基金financial assistance under the sponsored project "Novel materials for high energy reactions" (H/A: 4254) to Gulbarga University, Kalaburagi, India
文摘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.
基金ER&IPR,DRDO,New Delhi for funding the project “DRDO-DIAT Programme on Nanomaterials”
文摘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).
文摘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.
基金supported by the Natural Science Foundation of Guizhou Province(QKJ[2014]2140 and QJTD[2012]052)
文摘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.
文摘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.
基金supported by the Natural Science Foundation of Shanxi Province,China(grant No.202203021212147).
文摘Enhancing the safety of high-energy explosives(EMs)is crucial for the secure handling of energetic materials during storage,transportation,and use.Compositing multiple energetic materials effectively enhances the insensitivity of explosives.This study used N,N-dimethylformamide(DMF)as a solvent in the rotary evaporation method to prepare 1,1-diamino-2,2-dinitroethene/1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane(FOX-7/HMX)composite crystals.By varying the molar ratios of FOX-7 and HMX,this study investigated their effects on the morphology of the composite crystals,and the formation mechanism of the composite crystal was analyzed.The study characterized and tested the crystal structure,thermal decomposition,cook-off performance,and impact sensitivity of the composite crystal.The results indicate that at a 5:5 M ratio of FOX-7 to HMX,the compound degree is 90.79%,and FOX-7 exhibits uniform adhering to the surface of the HMX crystal.FT-IR and XRD patterns analyses revealed shifts in the absorption peak of the composite crystal and the characteristic peak of the XRD curve.FOX-7 crystals were embedded on the surface of HMX crystals,forming a co-crystal layer and altering the crystal structure.Differential scanning calorimetry tests demonstrate that the thermal decomposition temperature of FOX-7/HMX composite crystals is 1.77℃ higher than the raw FOX-7,and during the cook-off test,the composite crystal reaction level is combustion,accompanied by an increase in characteristic drop height to 62.6 cm,indicating improved thermal stability and impact safety.
基金Supporting information for this article is available on the WWW under http：//dx.doi.org/10.1002/cjoc.201280027 or from the author. Acknowledgment We gratefully acknowledge the financial support from the National Natural Science Foundation of China （No. 10776002） and China Academy of Engineering Physics （No. 20911120033）, the project of State Key Laboratory of Science and Technology （Nos. QNKT11-06, YBKT10-03）, and the Program for New Centu17 Excellent Talents in University （No. NCET-09-005I）. Our thanks are due to Professor Gustavo E. Scuseria for providing the development version of Gaussian program.
文摘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.
文摘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 .
