Journal of Material Sciences & Engineering

This paper investigates radiation effects in MgO using molecular dynamics (MD) simulations by single, 5 and 10 incident Au ions of energies ranging from 5-20 keV. The simulations employed a splined Buckingham+ZBL potential. The directional dependence of the threshold displacement energies (TDEs) for Frenkel pair formation and the TDE probability distributions for the displacement of an atom are calculated for both PKA types. The determined TDEs corresponding to 50% displacement probability of an atom by O and Mg PKAs are 94 eV and 91 eV, respectively. The effects of radiation by multiple ions are compared to those by 5-50 keV single Au ions. While the length of the produced defect cascade increases proportional to the total energy deposited, the volume of the defect clusters depends on the number of incident ions. For the same total energy, the volumes of the defect clusters produced by multiple incident ions are much larger than with single incident ions. The number of peak and residual defects produced with 10, 5-keV incident ions are an order of magnitude higher than with 5, 20-keV ions. The selected area electron diffraction (SAED) patterns and the radial distribution functions (RDFs) of the results show that 10 incident ions of 10 and 20 keV each, produce significant defects and cause ballistic melting at the peak of the ballistic phase of interaction. After annealing, the irradiated region recrystallizes, with some isolated amorphous pockets remaining. With 10, 20-keV incident ions, a cluster of ≈102,500 vacancies form at the peak of the ballistic phase, however, the number of residual vacancies is approximately 20 times lower. The sizes of the residual vacancy and interstitial clusters appear stable over the 50-100 picoseconds of the performed MD simulations.

This paper deals with a new approach of printing thin-walled parts with FDM technology by the use of continuous extrusion printing. Continuous extrusion printing is possible only if the part respects some specific constraints allowing a one-step printing path (no extrusion stop and no head travel). However, not all printing trajectories guarantee the same geometrical quality and mechanical strength due to the junctions of the path in the printing slices. This paper presents trajectory constraints in the case of continuous extrusion printing for thin-walled parts. A case study illustrates the principle, and some feasible trajectories are compared. The key problem of junction is presented, and the effect of path on geometrical quality and mechanical strength are evaluated.

The powerful techniques of recombinant DNA technology are applied in virtually every area of biological research. Consequently, a discussion of the future of recombinant DNA technology amounts to a consideration of the future of biological research in general. Perhaps the most dramatic recent impact of this technology is the sequencing of entire genomes of a number of organisms. As DNA sequences are determined, they are being stored in public databases, fully accessible to molecular cell biologists throughout the world.

Industrial engineering has been established since so many years ago over a century ago. In these particular industries no knowledge sharing, knowledge retention, knowledge sharing and experts in the particular field and other techniques all the work here is just the non-technical and this issue is coming across in last three decades.