The calculation of three-dimensional supersonic flows around spherically-capped smooth bodies and wings

"Work performed for the Air Force Flight Dynamics Laboratory...by the Aerodynamics Research Department of the Northrup Corporation, Aircraft Division."

Approaches to the calculation of limitations on nuclear detonations for peaceful purposes.

Paper presented as part of the National Center for Radiological Health's Seminar Program on Mar. 8, 1968, in Rockville, Md.

Tables for facilitating the calculation of earthwork in the construction of railways, roads, canals, dams, etc.,

Mode of access: Internet.

Calculation of electric conductors,

Mode of access: Internet.

Tabulae atomicae : the chemical tables for the calculation of quantitative analyses of H. Rose. Recalculated for the more recent determinations of atomic weights, and with other alterations and additions /

Mode of access: Internet.

The author's printing and publishing assistant, comprising explanations of the process of printing, preparation and calculation of manuscripts, choice of paper, type, binding, illustrations, publishing, advertising, & c. With an exemplification and description of the typographical marks used in the correction of the press.

Mode of access: Internet.

Research project 44 on the collection, analysis, and calculation of data on the properties of hydrocarbons ...

Imprint varies: later vols. published by Carnegie Institute of Technology, Pittsburgh, and by Texas A & M University, College Station.

Calculation of construction schedules and priorities with the aid of electronic computers,

Cover title.

A study of two calcium lines in Eridani, demonstrating the calculation of theoretical profiles by three methods,

Includes bibliography.

Short, easy, and improved method of finding the apparent time at ship. Rapid calculation of apparent time for finding the longitude.

Mode of access: Internet.

Vestiges of pre-metric weights and measures persisting in metric-system Europe, 1926-1927.

Half-title: Bureau of international research, Harvard university and Radcliffe college.

A distributed equivalent magnetic current based FDTD method for the calculation of E-fields induced by gradient coils

This paper evaluates a new, low-frequency finite-difference time-domain method applied to the problem of induced E-fields/eddy currents in the human body resulting from the pulsed magnetic field gradients in MRI. In this algorithm, a distributed equivalent magnetic current is proposed as the electromagnetic source and is obtained by quasistatic calculation of the empty coil's vector potential or measurements therein. This technique circumvents the discretization of complicated gradient coil geometries into a mesh of Yee cells, and thereby enables any type of gradient coil modelling or other complex low frequency sources. The proposed method has been verified against an example with an analytical solution. Results are presented showing the spatial distribution of gradient-induced electric fields in a multi-layered spherical phantom model and a complete body model. (C) 2004 Elsevier Inc. All rights reserved.

An FDTD model for calculation of gradient-induced eddy currents in MRI system

In most magnetic resonance imaging (MRI) systems, pulsed magnetic gradient fields induce eddy currents in the conducting structures of the superconducting magnet. The eddy currents induced in structures within the cryostat are particularly problematic as they are characterized by long time constants by virtue of the low resistivity of the conductors. This paper presents a three-dimensional (3-D) finite-difference time-domain (FDTD) scheme in cylindrical coordinates for eddy-current calculation in conductors. This model is intended to be part of a complete FDTD model of an MRI system including all RF and low-frequency field generating units and electrical models of the patient. The singularity apparent in the governing equations is removed by using a series expansion method and the conductor-air boundary condition is handled using a variant of the surface impedance concept. The numerical difficulty due to the asymmetry of Maxwell equations for low-frequency eddy-current problems is circumvented by taking advantage of the known penetration behavior of the eddy-current fields. A perfectly matched layer absorbing boundary condition in 3-D cylindrical coordinates is also incorporated. The numerical method has been verified against analytical solutions for simple cases. Finally, the algorithm is illustrated by modeling a pulsed field gradient coil system within an MRI magnet system. The results demonstrate that the proposed FDTD scheme can be used to calculate large-scale eddy-current problems in materials with high conductivity at low frequencies.

First-principle density-functional calculation of the Raman spectra of BEDT-TTF

We present a first-principles density-functional calculation for the Raman spectra of a neutral BEDT-TTF molecule. Our results are in excellent agreement with experimental results. We show that a planar Structure is not a stable state of a neutral BEDT-TTF molecule. We consider three possible conformations and discuss their relation to disorder in these systems.

Calculation of the microcanonical temperature for the classical Bose field

The ergodic hypothesis asserts that a classical mechanical system will in time visit every available configuration in phase space. Thus, for an ergodic system, an ensemble average of a thermodynamic quantity can equally well be calculated by a time average over a sufficiently long period of dynamical evolution. In this paper, we describe in detail how to calculate the temperature and chemical potential from the dynamics of a microcanonical classical field, using the particular example of the classical modes of a Bose-condensed gas. The accurate determination of these thermodynamics quantities is essential in measuring the shift of the critical temperature of a Bose gas due to nonperturbative many-body effects.