Relation between the critical detonation diameter of explosive charges with characteristics of their shock-wave sensitivity

Correlation dependences between the critical diameter of high explosive (HE) charges and characteristics of their shock-wave sensitivity are theoretically justified. Relations for the critical radius of curvature of the detonation-wave front and for the critical detonation diameter are derived on the basis of the author’s theory of the critical diameter and the generalized kinetic characteristic of HE decomposition determined from the experimental dependence of the distance of transition of the initiating shock wave to the detonation wave on the wave amplitude. A qualitative analysis of these relations reveals good agreement with available experimental data. Key words: detonation, critical diameter, sensitivity, shock-wave initiation of detonation, HE decomposition kinetics. __________ Translated from Fizika Goreniya i Vzryva, Vol. 45, No. 3, pp. 101–105, May–June, 2009.     

磨球的冲击作用与选材

磨球的冲击功与球磨机直径、转速、脱离角、磨球直径和材质有关。当磨机参数一定时,可根据计算的冲击功选择磨球材料,从而确定磨球的尺寸。本文提供的经验公式可作为实际工作的参考。     

Relation between impact strength and dynamic mechanical properties of plastics

A simple theory is developed which correlates the Izod impact strength of polymers with (G′₁₀₀-G′₃₀₀)²/G′₁₀₀, where G′₁₀₀ and G′₃₀₀ are dynamic shear moduli at 100°K. and 300°K., respectively. The theory assumes the Maxwell element for the material and the fracture time smaller than the relaxation time. The theory is verified by experimental data for numerous polymers. Another approach which correlates the impact strength with the integrated loss factor from 0 to 300°K. is also proved valid.     

Relationship between the flammability of solid explosives and their sensitivity to impact and shock

Moscow. Translated from Fizika Goreniya i Vzryva, Vol. 26, No. 1, pp. 125–129, January–February, 1990.     

炸药撞击感度的研究综述

综述了炸药撞击感度的发展应用情况,分析了实验现象的判定依据及撞击感度的影响因素,指出了撞击感度研究的重要性。     

Burning of nitroglycerine powder in vacuum and at subatmospheric pressures

Summary Temperature profiles have been obtained for the stable burning of N powder at pressures from p0.5 mm Hg to p=620 mm Hg and different initial temperatures. The surface temperatures of the burning powder have been found. The burning rates, the temperature coefficients of the burning rates, and values of the criterion (T_s–T₀) have been found as functions of pressure and initial temperature. The amount of heat released in the condensed phase and supplied from the gas phase to the condensed phase has been calculated.It has been shown that at pressures less than 220 mm Hg a stability criterion allowing for the inertia of the reaction layer of the condensed phase (at constant surface temperature) applies, while at pressures of 220 mm Hg and above a criterion obtained with allowance for the variable (with pressure) surface temperature and based on the assumption that the reaction zones are inertialess is also valid.Fizika Goreniya i Vzryva, Vol. 2, No. 1, pp. 74–78, 1966     

Research progress of microbial decomposition of nitroglycerine and nitrocellulose

硝酸酯类物质（如硝化甘油和硝化棉等）是有机羟基基团与硝酸缩合的产物,在军事工业上有非常广泛的用途。由于它们并非天然存在的物质,且有爆炸等潜在危害,故不能直接排放到环境中。作为地球生物化学循环中分解者的微生物对硝酸酯类物质的生物降解起着很大的作用,本文将对硝化甘油和硝化棉的生物降解研究进展进行综述。     

黑索今结晶工艺对其撞击感度的影响研究

本文以结晶机理为指导,硝酸为溶剂,水为稀释剂,采用溶剂-非溶剂法重结晶黑索今．用立式落锤仪测定其撞击感度。通过工艺条件的改变,寻求黑索今撞击感度与结晶工艺的关系。试验结果表明：黑索今晶体的撞击感度与其结晶工艺密切相关。     

Interrelations between constitution,configuration and conformation in chlorinated polyalkenamers

Summary FTIR-Spectra of poly-1,2-dichloroalkanes are reported as a function of the constitution and of the configuration of the subunits and of the temperature. The intensity of the C-Cl-vibrations of the head-to-head chlorinated polymers with variable tail length seems to be sensitive to changes in configuration and conformation and also to changes in the surrounding of the absorbing group. We conclude from these experiments that an intensity ratio of the different conformers corresponds to every degree of stereoregularity, which is overlapped with the influence of polarity on the absorbance. Assuming that the conformational equilibrium in chlorinated polymers is insensitive against minor disturbances — swelling or blending — the IR-intensity offers information concerning placement and degree of polymer contacts and interactions in polymer blends as well as in plasticized polymers.Prof. Dr. O. Wichterle zum 75. Geburtstag herzlichst gewidmet     

Some regularities of the initiation of an explosion in nitroglycerin during collapse of air cavities after an impact

Combustion, Explosion, and Shock Waves -     

浅析网络媒介与传播的关系

随着高科技的发展和信息化建设的深入,网络媒介将成为未来的主流媒体,而且还为人类的传播活动提供了一个崭新的平台,通过这个平台,人们可以向广大公众进行开放式的大众传播,可以从事横向和纵向的组织传播,人们也可以向特定的对象进行人际传播。     

Temperature effects on the birefringence of nitrocellulose and nitrocellulose/nitroglycerine mixtures

Changes in the optical path difference of nitrocellulose fibres of varying degrees of substitution over the temperature range ?120°C to 130°C are interpreted as due to conformational changes in the primary nitrate group. Changes in path difference of nitrocellulose/nitroglycerine paste fibres over the same temperature range indicate an irreversible annealing effect and a change in the nitrocellulose structure. Propellants made from nitrocellulose and nitroglycerine show similar changes and it is concluded that submicroscopic fibrils are present even though no fibres are visible. When fibres are visible they show a banded structure, the nature of which is discussed.     

Relation between the coking properties and quality of coke

On the basis of laboratory data for production batch employed at AO Evraz NTMK and AO Evraz ZSMK, including batch that contains Ulug-Khem coal, a coking characteristic is proposed. This characteristic permits relatively precise prediction of CSR and CRI. Its relation with the quality of coke produced by the classical method and from rammed coal batch is analyzed.     

Reduction of notch sensitivity and improvement in low-temperature impact strength of PVC

PVC is a notch-sensitive polymer. The drop weight impact strength is also lost dramatically below 0°C. This requires special formulation considerations for critical applications. The general trend is to use polymeric impact modifiers, which are rubbery, graft polymers or blends of both hard and rubbery materials. This is achieved with some sacrifice in flexural modulus and formulation economics. A recent study conducted to relate calcium carbonate particle size with notched Izod and low-temperature drop weight impact strength has shown that the stearate-coated Ultrafine precipitated calcium carbonate (0.07 μ), at 15 phr loading, substantially improves both properties without sacrifice in flexural modulus. The formulation cost is also favorable. It is hypothesized that improvement in the above properties is primarily due to uniform stress distribution and lack of defect structure, as observed with coarse fillers. Surprisingly, the optimum-particle-size, coated, precipitated calacium carbonates also improved the Ultraviolet light stability of the PVC.     

Failure and fragmentation of ceramic target with varying geometric configuration under ballistic impact

The failure and fragmentation of monolithic bare alumina 99.5% ceramic target and energy dissipation of steel 4340 projectile have been studied in a series of ballistic experiments carried out, with the incidence velocities in a range, 122–290 m/s. The velocity drop and energy dissipation increased with incidence velocity for 10 mm thick target with damage zone extended upon the whole area of rear face at higher velocities. The ballistic results obtained with the 10 mm thick target have been compared with the ballistic performance of the 5 mm thick target used in a previous study to explore the effects of target thickness on the failure mechanism. A model for the residual velocity of projectile after perforation of the single layered ceramic target has been developed based on the Lambert Jonas model by using the experimental data available for 5 mm and 10 mm thick alumina 99.5% target against 10.9 mm projectile. The residual velocities and damage patterns were reproduced with a reasonable amount of accuracy by a three-dimensional finite element model developed on commercial ABAQUS/CAE. The effect of obliquity and projectile diameter to target thickness ratio (D/T) on ballistic performance has been determined by the numerical simulation model with impact velocity in a range of 300–500 m/s. A spatial variation of ejected fragments velocity at different time steps was plotted to develop a velocity profile for the ceramic fragments coming out of the target. A semi-empirical model has been proposed for residual velocity after perforation of a monolithic ceramic target, relating to the incidence velocity and projectile diameter to target thickness ratio. The monolithic ceramic targets have been investigated for a comparative assessment of energy dissipation by the ceramic layer to eventually design an efficient front layer of a ceramic based composite armour in future studies.