Advances in induction-heated plasma torch technology

Continuing research has resulted in significant advances in induction-heated plasma torch technology which extend and enhance its potential for broad range of uses in chemical processing, materials development and testing, and development of large illumination sources. Summaries of these advances are briefly described

Induction plasma nozzle tests

Simulation of nozzle environment in gas core nuclear rocket with induction coupled arc plasma syste

Tacit knowledge and the biological weapons regime

Bioterrorism has become increasingly salient in security discourse in part because of perceived changes in the capacity and geography of life science research. Yet its salience is founded upon a framing of changes in science and security that does not always take into consideration the somewhat slippery concept of ‘tacit knowledge’, something poorly understood, disparately conceptualised and often marginalised in discussions on state and non-state biological weapons programmes. This paper looks at how changes in science and technology—particularly the evolution of information and communications technology—has contributed to the partial erosion of aspects of tacit knowledge and the implications for the biological weapons regime. This paper concludes by arguing that the marginalisation of tacit knowledge weakens our understanding of the difficulties encountered in biological weapons programmes and can result in distorted perceptions of the threat posed by dual-use biotechnology in the 21st century

Effective Operators for Double-Beta Decay

We use a solvable model to examine double-beta decay, focusing on the neutrinoless mode. After examining the ways in which the neutrino propagator affects the corresponding matrix element, we address the problem of finite model-space size in shell-model calculations by projecting our exact wave functions onto a smaller subspace. We then test both traditional and more recent prescriptions for constructing effective operators in small model spaces, concluding that the usual treatment of double-beta-decay operators in realistic calculations is unable to fully account for the neglected parts of the model space. We also test the quality of the Quasiparticle Random Phase Approximation and examine a recent proposal within that framework to use two-neutrino decay to fix parameters in the Hamiltonian. The procedure eliminates the dependence of neutrinoless decay on some unfixed parameters and reduces the dependence on model-space size, though it doesn't eliminate the latter completely.Comment: 10 pages, 8 figure

Dating possibilities for the South African hominid sites

Main articleA brief description is given of dating methods which may in future prove to be applicable to the calcified ossiferous cave deposits of the early hominid sites in the Transvaal. Potentially the techniques based on amino acid racemisation, uranium series disequilibrium and radiation damage could provide dates for at least the upper members of the cave formations. The results would, however, have. to be calibrated in the younger time-range by radiocarbon dating of parallel samples.Non

Bone mineral measurement from Apollo experiment M-078

Loss of mineral from bone during periods of immobilization, recumbency, or weightlessness is examined. This report describes the instrumentation, technique, and bone mineral changes observed preflight and postflight for the Apollo 14, 15, and 16 missions. The bone mineral changes documented during the Apollo Program are reviewed, and their relevance to future missions is discussed

Spatially heterogeneous dynamics and dynamic facilitation in a model of viscous silica

Performing molecular dynamics simulations, we find that the structural relaxation dynamics of viscous silica, the prototype of a strong glass former, are spatially heterogeneous and cannot be understood as a statistical bond breaking process. Further, we show that high particle mobility predominantly propagates continuously through the melt, supporting the concept of dynamic facilitation emphasized in recent theoretical work.Comment: 4 pages, 4 figure