Plasticity and decomposition of whiskers on electric-induced deformation

The purpose of the work is to study the influence of weak electric fields (1–10 V/cm) on the micro and macroplasticity of whisker crystals of silver azide. The paper considers the processes occurring in the crystals of silver azide on the indentation in noncontact electric field. One of the processes is the indenter-induced movement of unfixed dislocations, which is the evidence of crystals microplasticity, followed by the accumulation of dislocations at the impediments of different nature. Further, this causes the change in linear dimensions of the crystals and the return to original dimensions, which is the evidence of macroplasticity. After deformation, a greater number of dislocations are formed, which stops the formation of the reaction areas where outgassing is observed. A method for controlling the whiskers stability and reactivity using the microindentation in electric field is proposed

Processing of energy materials in electromagnetic field

This paper presents the research results of complex impact of mechanical stress and electromagnetic field on the defect structure of energy materials. As the object of research quite a typical energy material - silver azide was chosen, being a model in chemistry of solids. According to the experiments co-effect of magnetic field and mechanical stress in silver azide crystals furthers multiplication, stopper breakaway, shift of dislocations, and generation of superlattice dislocations - micro-cracks. A method of mechanical and electric strengthening has been developed and involves changing the density of dislocations in whiskers

Controlling Explosive Sensitivity of Energy-Related Materials by Means of Production and Processing in Electromagnetic Fields

The present work is one of the world first attempts to develop effective methods for controlling explosive sensitivity of energy-related materials with the help of weak electric (up to 1 mV/cm) and magnetic (0.001 T) fields. The resulting experimental data can be used for purposeful alternation of explosive materials reactivity, which is of great practical importance. The proposed technology of producing and processing materials in a weak electric field allows forecasting long-term stability of these materials under various energy impacts

Simulation of the Reactivity of Energy Materials in the Technosphere

Methods are proposed for regulating the reactivity of energetic materials that circulate in the technosphere and are not rarely the cause of fires and explosions, both during storage and during transportation. As man-made factors that influence the stability of these materials magnetic and temperature fields and mechanical effects were used. The magnetic field (in the range from 0.01 T to 0.3 T) was used to intensify chemical processes, both at the stage of crystal growth (by the example of silver azide) and together with mechanical action (from 105 Pa to 107 Pa) in the finished crystals. The action of the magnetic field and mechanical stress leads to the stimulation of microplasticity and macroplasticity processes, which are accompanied by a slow decomposition of the samples and subsequent destruction. It was established experimentally that a slight change in storage temperature, as compared to room temperature, accelerates the aging process of samples (range of positive temperatures up to + 30°C), or leads to loss of plasticity (range of negative temperatures down to -20°C) resulting in loss of performance and in loss of useful properties of energy materials

IncN plasmid pKM101 and IncI1 plasmid ColIb-P9 encode homologous antirestriction proteins in their leading regions.

The IncN plasmid pKM101 (a derivative of R46), like the IncI1 plasmid ColIb-P9, carries a gene (ardA, for alleviation of restriction of DNA) encoding an antirestriction function. ardA was located about 4 kb from the origin of transfer, in the region transferred early during bacterial conjugation. The nucleotide sequence of ardA was determined, and an appropriate polypeptide with the predicted molecular weight of about 19,500 was identified in maxicells of Escherichia coli. Comparison of the deduced amino acid sequences of the antirestriction proteins of the unrelated plasmids pKM101 and ColIb (ArdA and Ard, respectively) revealed that these proteins have about 60% identity. Like ColIb Ard, pKM101 ArdA specifically inhibits both the restriction and modification activities of five type I systems of E. coli tested and does not influence type III (EcoP1) restriction or the 5-methylcytosine-specific restriction systems McrA and McrB. However, in contrast to ColIb Ard, pKM101 ArdA is effective against the type II enzyme EcoRI. The Ard proteins are believed to overcome the host restriction barrier during bacterial conjugation. We have also identified two other genes of pKM101, ardR and ardK, which seem to control ardA activity and ardA-mediated lethality, respectively. Our findings suggest that ardR may serve as a genetic switch that determines whether the ardA-encoded antirestriction function is induced during mating