Ultrasonic peening treatment (UPT) as a method of severe plastic deformation was used to treat cruciform welded joints of Q345 steel. The application of UPT achieves material surface nanocrystallization of the peening zone, reduces stress concentration, and produces residual compressive stresses at the welded toe. Micro-structure, hardness, stress relief, S-N curve, and the fatigue fracture mec...

Inverted repeat (IR) sequences in DNA can form noncanonical cruciform structures to relieve torsional stress. We use Monte Carlo simulations of a recently developed coarse-grained model of DNA to demonstrate that the nucleation of a cruciform can proceed through a cooperative mechanism. First, a twist-induced denaturation bubble must diffuse so that its midpoint is near the center of symmetry o...

In this paper, a new guidance method for surface to surface ballistic missiles without mandatory engine cut-off will be presented. The complexity of solid fuel engine cut-off demands a comprehensive method for guiding these missiles. In the method presented in this paper, a certain guidance law is applied such that by transmitting appropriate commands to the control system, by changing the miss...

We studied the formation of d(A-T)n cruciforms in E.coli cells by probing intracellular plasmid DNA with chloroacetaldehyde followed by fine analysis of modified DNA bases. d(A-T)16 sequences were inserted into specifically designed plasmids either upstream of a single trc promoter, or between two divergent trc promoters. We found that in both cases, induction of transcription by IPTG leads to ...

In this paper, a new guidance method for surface to surface ballistic missiles without mandatory engine cut-off will be presented. The complexity of solid fuel engine cut-off demands a comprehensive method for guiding these missiles. In the method presented in this paper, a certain guidance law is applied such that by transmitting appropriate commands to the control system, by changing the miss...

The Fighter problem with discrete ammunition is studied. An aircraft (fighter) equipped with n anti-aircraft missiles is intercepted by enemy airplanes, the appearance of which follows a homogeneous Poisson process with known intensity. If j of the n missiles are spent at an encounter they destroy an enemy plane with probability a(j), where a(0) = 0 and {a(j)} is a known, strictly increasing co...

Popular Science & Technology (PST) series is being published by DESIDOC to promote the knowledge and understanding of the applications of science and technology in Defence among defence personnel, students, and general public. The contents covered in each of the titles are current to the year of publication. Popular Science 8c Technology (PST) is a half-yearly publicatior~ of DESIDOC and it end...

Some viable palindromic DNA sequences were found to cause an increase in the recovery of genetic recombinants. Although these palindromes contained no Chi sites, their presence in cis caused apparent recA+-dependent recombination to increase severalfold. This biological property did not correlate with the physical properties of the palindromes' extrusion of cruciform structures in vitro. Thus, ...

We have made an analysis of the gel electrophoretic properties of a pseudo-cruciform fragment, a linear DNA molecule containing a stable cruciform. The migration of this construct was analysed in polyacrylamide gels at a various temperatures in the range 5 degrees to 55 degrees C, and in the presence of NaCl, MgCl2 or ethidium bromide. The magnitude of the anomalous migration (retardation) was ...