[en] A serial communications system based on the EIA RS232-C standard with modem control lines has been developed. The DLV11-E interface is used for this purpose. All handshaking is done with the modem control lines. This allows totally independent full duplex communication. The message format consists of eight bit data with odd parity and a sixteen bit checksum on the whole message. All communications are fully interrupt driven. A program was written to load a program into a remote LSI-11 using the serial line without bootstrap ROM

[en] Studies of the electromagnetic loads produced by a variety of plasma disruptions, and the resulting structural effects on the compact Ignition Tokamak (CIT) vacuum vessel (VV), have been performed to help optimize the VV design. A series of stationary and moving plasmas, with disruption rates from 0.7--10.0 MA/ms, have been analyzed using the EMPRES code to compute eddy currents and electromagnetic pressures, and the NASTRAN code to evaluate the structural response of the vacuum vessel. Key factors contributing to the magnitude of EM forces and resulting stresses on the vessel have been found to include disruption rate, and direction and synchronization of plasma motion with the onset of plasma current decay. As a result of these analyses, a number of design changes have been made, and design margins for the present 1.75 meter design have been improved over the original CIT configuration. 1 ref., 10 figs., 4 tabs

[en] Where there is a strong interaction between fluid flow, heat transfer and stress induced deformation, it may not be sufficient to solve each problem separately (i.e. fluid vs. stress, using different techniques or even different computer codes). This may be acceptable where the interaction is static, but less so, if it is dynamic. It is desirable for this reason to develop software that can accommodate both requirements (i.e. that of fluid flow and that of solid mechanics) in a seamless environment. This is accomplished in the University of Greenwich code PHYSICA, which solves both the fluid flow problem and the stress-strain equations in a unified Finite-Volume environment, using an unstructured computational mesh that can deform dynamically. Example applications are given of the work of the group in the metals casting process (where thermal stresses cause elasto- visco-plastic distortion)

[en] As modern industrial processes make greater and greater use of an ever increasing array of chemical substances the risk of these materials entering public sewer systems increases commensurately. Compounding this problem is the additional issue of a large population of single walled underground storage tanks now reaching the end of their safe-use lifespan while continuing in service. Tanks first put into underground service twenty to thirty years ago are now beginning to fail in ever increasing numbers releasing hazardous substances into the Vadose zone and ultimately into waste-water collection infrastructures. This paper, through the examination of a case study involving diesel fuel in a large, municipal waste-water collection system, offers a prototypical methodology for the management of such incidents

[en] The authors discuss studies of the electromagnetic loads produced by a variety of plasma disruptions, and the resulting structural effects on the Compact Ignition Tokamak (CIT) vacuum vessel (VV), have been performed to help optimize the VV design. A series of stationary and moving plasmas, with disruption rates from 0.7 - 10.0 MA/ms, have been analyzed using the EMPRES code to compute eddy currents and electromagnetic pressures, and the NASTRAN code to evaluate the structural response of the vacuum vessel. Key factors contributing to the magnitude of EM forces and resulting stresses on the vessel have been found to include disruption rate, and direction and synchronization of plasma motion with the onset of plasma current decay

[en] Focused Ion Beam (FIB) and Nano-Imprint Forming (NIF) have gained recently major interest because of their potential to enable the fabrication of precision engineering parts and to deliver high resolution, low-cost and high-throughput production of fine sub-micrometre structures respectively. Using computational modelling and simulation becomes increasingly important in assessing capabilities and risks of defects with respect to product manufacturability, quality, reliability and performance, as well as controlling and optimising the process parameters. A computational model that predicts the milling depth as function of the ion beam dwell times and a number of process parameters in the case of FIB milling is investigated and experimentally validated. The focus in the NIF study is on modelling the material deformation and the filling of the pattern grooves during the mould pressing using non-linear large deformation finite element analysis with hyperelastic non-compressive material behaviour. Simulation results are used to understand the risk of imperfections in the pattern replication and to identify the optimal process parameters and their interaction.

[en] At the National Institute of Standards and Technology (NIST) and Indiana University, we are developing polarized ³He analyzers for neutron reflectometry. We have employed ³He analyzers at two polarized neutron reflectometers, NG1 at the NIST Center for Neutron Research (NCNR) and POSY I at the Intense Pulsed Neutron Source (IPNS), Argonne National Laboratory. The long-term goal for both efforts is to perform efficient studies of magnetic diffuse scattering. At the NCNR, we tested a ³He analyzer by comparing measurements of specular scattering obtained with a supermirror analyzer to those obtained with a ³He analyzer. For this test, we measured the spin-flip and nonspin-flip scattering from a Mn_0.52Pd_0.48/Fe thin film. The results with the ³He analyzer show very good agreement with those obtained with the supermirror analyzer. We have also carried out tests of the ³He analyzer for application to magnetic diffuse scattering experiments. We discuss the development of a ³He analyzer for IPNS that will be employed for studies of patterned magnetic arrays

[en] We study the quantum dynamics of a nonrelativistic neutral particle with spin in inhomogeneous external magnetic fields. We first consider fields with one-dimensional inhomogeneities, both unphysical and physical, and construct the corresponding analytic propagators. We then consider fields with two-dimensional inhomogeneities and develop an appropriate numerical propagation method. We propagate initial states exhibiting different degrees of space localization and various initial spin configurations, including both pure and mixed spin states. We study the evolution of their spin densities and identify characteristic features of spin density dynamics, such as the spatial separation of spin components, and spin localization or accumulation. We compare our approach and our results with the coverage of the Stern-Gerlach effect in the literature, and we focus on nonstandard Stern-Gerlach outcomes, such as radial separation, spin focusing, spin oscillation, and spin flipping.

[en] Our paper describes a novel method to determine the constant systematic error (bias) in the temperature RTDs of the Reactor Inlet Headers (TRIH). This is done by analysing the TRIH responses to a reactor run-up. This method provides an independent check for TRIH biases which are directly measured by removing the RTDs from their thermowells, placing them in an oven, and comparing their responses to a high-precision RTD. Overall, work on assessing TRIH errors has resulted in a significant reduction in PHT boundary condition uncertainties and a subsequent decrease in required operating margins. (author)

[en] From first-principles approaches, we investigate the thermoelectric efficiency of a molecular junction where a benzene molecule is connected directly to the platinum electrodes. We calculate the thermoelectric figure of merit ZT in the presence of electron–vibration interactions with and without local heating under two scenarios: linear response and finite bias regimes. In the linear response regime, ZT saturates around the electrode temperature T_e = 25 K in the elastic case, while in the inelastic case we observe a non-saturated and a much larger ZT beyond T_e = 25 K attributed to the tail of the Fermi–Dirac distribution. In the finite bias regime, the inelastic effects reveal the signatures of the molecular vibrations in the low-temperature regime. The normal modes exhibiting structures in the inelastic profile are characterized by large components of atomic vibrations along the current density direction on top of each individual atom. In all cases, the inclusion of local heating leads to a higher wire temperature T_w and thus magnifies further the influence of the electron–vibration interactions due to the increased number of local phonons. (paper)