Combining high performance simulation, data acquisition, and graphics display computers

Issues involved in the continuing development of an advanced simulation complex are discussed. This approach provides the capability to perform the majority of tests on advanced systems, non-destructively. The controlled test environments can be replicated to examine the response of the systems under test to alternative treatments of the system control design, or test the function and qualification of specific hardware. Field tests verify that the elements simulated in the laboratories are sufficient. The digital computer is hosted by a Digital Equipment Corp. MicroVAX computer with an Aptec Computer Systems Model 24 I/O computer performing the communication function. An Applied Dynamics International AD100 performs the high speed simulation computing and an Evans and Sutherland PS350 performs on-line graphics display. A Scientific Computer Systems SCS40 acts as a high performance FORTRAN program processor to support the complex, by generating numerous large files from programs coded in FORTRAN that are required for the real time processing. Four programming languages are involved in the process, FORTRAN, ADSIM, ADRIO, and STAPLE. FORTRAN is employed on the MicroVAX host to initialize and terminate the simulation runs on the system. The generation of the data files on the SCS40 also is performed with FORTRAN programs. ADSIM and ADIRO are used to program the processing elements of the AD100 and its IOCP processor. STAPLE is used to program the Aptec DIP and DIA processors

General formalism for vibronic Hamiltonians in tetragonal symmetry and beyond

We derive general expansion formulas in vibrational coordinates for all bimodal Jahn–Teller and pseudo-Jahn–Teller Hamiltonians in tetragonal symmetry. Symmetry information of all the vibronic Hamiltonian matrix elements is fully carried by up to only 4 eigenvalues of symmetry operators. This problem-to-eigenvalue reduction enables us to handle thousands of vibronic problems in one work. The derived bimodal formulas can be easily extended to cover problems with one or more than two vibrational modes. They lay a solid foundation for future vibronic coupling studies of tetragonal systems. More importantly, the efficient derivation can be applied to handle (pseudo-)Jahn–Teller Hamiltonians for all problems with one principal symmetry axis

Structural Design Concepts for a Multi-Megawatt Solar Electric Propulsion (SEP) Spacecraft

As a part of the Space Exploratory Initiative (SEI), NASA-Lewis is studying Solar Electric Propulsion (SEP) spacecraft to be used as a cargo transport vehicle to Mars. Two preliminary structural design concepts are offered for SEP spacecraft: a split blanket array configuration, and a ring structure. The split blanket configuration is an expansion of the photovoltaic solar array design proposed for Space Station Freedom and consists of eight independent solar blankets stretched and supported from a central mast. The ring structural concept is a circular design with the solar blanket stretched inside a ring. This concept uses a central mast with guy wires to provide additional support to the ring. The two design concepts are presented, then compared by performing stability, normal modes, and forced response analyses for varying levels of blanket and guy wire preloads. The ring structure configuration is shown to be advantageous because it is much stiffer, more stable, and deflects less under loading than the split blanket concept

What is a prisoner of war for?

This article presents a conceptual map of the purposes served by continuing custody of prisoners of war and captured non-combatants. Morally legitimate and non-controversial purposes include preventing prisoners of war from rejoining their comrades-in-arms, preventing both prisoners of war and captured non-combatants from giving material support to combatants still in the field, facilitating orderly release and repatriation at the end of hostilities, and the prosecution for war crimes. Morally illegitimate purposes include punishment, exploitation as conscript labour, recruitment or conscription as combatants, exploitation for intelligence, display as proof of victory, and ideological indoctrination. Analysis of historical cases illustrating each purpose reveal that continuing custody is often motivated by multiple purposes, both legitimate and illegitimate. What explains adoption of multiple and illegitimate purposes for continuing custody? Prisoners are available for legitimate and illegitimate purposes because neither elites nor masses within the captor state typically view prisoners as members of the moral community.1 Continuing custody does not alter the perceived status of the captured as aliens who cannot be intuitively invested with expectations of reciprocity. This suggests both ending custody as soon as legitimate purposes are served and bringing the captured within the moral community while in continuing captivity. Scientia Militaria: South African Journal of Military Studies Vol. 36 (2) 2008: pp. 19-3

The Pacific Basin in World Trade: Part III, An Analysis of Changing Trade Patterns, 1955-1975

This is the third of a sequence of papers on international flows of trade among fifteen Pacific Basin (PB) countries and between them and eleven regions in the Rest of the World (ROW). In Part I of the sequence (Hickman, Kuroda and Lau, 1977a) we presented and documented annual data on bilateral flows of total exports valued f.o.b. in current dollars among the twenty-six countries and regions for the years 1948 through1975. The primary data source is the Direction of Trade computer tape of the International Monetary Fund, but these data were supplemented from other sources, especially as regards the international trade of the socialist countries. The second report (1977b) extended the data base to include unit value export price indexes and the corresponding constant dollar trade flow matrices for the period 1955-1975. In this third report we analyze the changing pattern of PB trade over the same period, using as tools export growth decomposition indexes, trend analysis, and regression analysis of the price elasticity of import market shares. The present paper is organized as follows. In Section 2 we describe the trends in the export performance of the PB countries and ROW regions, as measured by the cumulative percentage change in each country's share of world exports between 1955 and 1975 and for selected sub periods. In Section 3 and Appendices B and C these export share changes are decomposed into three sources: changes in the degree of penetration of the various import markets, changes in the size of the import markets themselves, and an interaction effect. The decomposition indexes are shown in Section 4 to be dominated by the market penetration or competitiveness effect, so that a country gains or loses in world trade according to whether or not it can increase its shares of the markets in which it sells rather than as a passive result of changes in the size of the markets themselves. This leads to a descriptive analysis in Section 5 of the secular growth rates of the market shares of each country or region in the import markets of the twenty-five remaining countries and regions. Finally, we conclude the paper in Section 6 with art exploratory regression analysis of the responsiveness of the market shares to changes in the relative prices of the various exporting countries competing in each import market, leading to the general conclusion that relative prices do matter and presenting estimates of share or substitution elasticities in the various import markets.

The Pacific Basin in World Trade: Part II, Constant-Price Trade Matrices, 1955-1975

This is the second of a sequence of papers on international flows of merchandise trade among fifteen Pacific Basin countries and between them and eleven regions in the Rest of the World. In the first paper in this sequence (Hickman, Kuroda and Lau (1977)) we presented annual data on bilateral flows of exports in current prices among the twenty-six countries and regions for the years 1948 through 1975. The basic purpose of this second report is to present and document data on annual export price indexes of the twenty-six countries and regions and annual bilateral flows of exports in constant U.S. dollar prices among the twenty-six countries and regions in matrix form from 1955 through 1975. A third report will analyze the changing pattern of Pacific Basin trade over the same period. The present report is organized as follows: In Section 2 we present the data sources for the export price indexes. Using these export price indexes, the current price trade matrices derived in the first report(Hickman, Kuroda and Lau (1977)) are deflated to obtain the constant price trade matrices. In Section 3 we examine whether the concept of a Pacific Basin regional economy may still be justified when viewed in a constant price context and describe the postwar trends in its share of world trade and in its internal trading relationships on a constant price basis. In Section 4 we present terms of trade indexes for each country and region from 1955 through 1975 and discuss some of their implications.

Elliptical flux vortices in YBa2Cu3O7

The most energetically favorable vortex in YBa2Cu3O7 forms perpendicular to an anisotropic plane. This vortex is elliptical in shape and is distinguished by an effective interchange of London penetration depths from one axis of the ellipse to another. By generalizing qualitatively from the isotropic to the anisotropic case, we suggest that the flux flow resistivity for the vortex that forms perpendicular to an anistropic plane should have a preferred direction. Similar reasoning indicates that the Kosterlitz-Thouless transition temperature for a vortex mediated transition should be lower if the vortex is elliptical in shape