Preferences for content, skills and aesthetic subjects in five communities

Thesis (Ed.M.)--Boston Universit

QCD at high energy

I review recent results in QCD at high energy, emphasizing the role of higher-order computations, power corrections, and Monte Carlo simulations in the study of a few discrepancies between data and perturbative predictions, and discussing future prospects.Comment: 20 pages Latex; 9 figures included. Plenary talk given at ICHEP02, 24 - 31 July 2002, Amsterdam. Affiliation correcte

Atmospheric environment for Space Shuttle (STS-41D) launch

Selected atmospheric conditions observed near Space Shuttle STS-41D launch time on August 30, 1984, at Kennedy Space Center, Florida are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given as well as wind and thermodynamic parameters representative of surface and aloft conditions in the SRB descent/impact ocean area. Final atmospheric tapes, which consist of wind and thermodynamic parameters versus altitude, for STS-41D vehicle ascent and SRB descent/impact were constructed. The STS-41D ascent meteorological data tape was constructed by Marshall Space Flight Center's Atmospheric Science Division to provide an internally consistent data set for use in post flight performance assessments

Asymptotic integration algorithms for nonhomogeneous, nonlinear, first order, ordinary differential equations

New methods for integrating systems of stiff, nonlinear, first order, ordinary differential equations are developed by casting the differential equations into integral form. Nonlinear recursive relations are obtained that allow the solution to a system of equations at time t plus delta t to be obtained in terms of the solution at time t in explicit and implicit forms. Examples of accuracy obtained with the new technique are given by considering systems of nonlinear, first order equations which arise in the study of unified models of viscoplastic behaviors, the spread of the AIDS virus, and predator-prey populations. In general, the new implicit algorithm is unconditionally stable, and has a Jacobian of smaller dimension than that which is acquired by current implicit methods, such as the Euler backward difference algorithm; yet, it gives superior accuracy. The asymptotic explicit and implicit algorithms are suitable for solutions that are of the growing and decaying exponential kinds, respectively, whilst the implicit Euler-Maclaurin algorithm is superior when the solution oscillates, i.e., when there are regions in which both growing and decaying exponential solutions exist

Design, development, and fabrication of a electronic analog microminiaturized electronic analog signal to discrete time interval converter

The microminiaturization of an electronic analog signal to discrete time interval converter is presented. Discrete components and integrated circuits comprising the converter were assembled on a thin-film ceramic substrate containing nichrome resistors with gold interconnections. The finished assembly is enclosed in a flat package measuring 3.30 by 4.57 centimeters. The module can be used whenever conversion of analog to digital signals is required, in particular for the purpose of regulation by means of pulse modulation. In conjunction with a precision voltage reference, the module was applied to control the duty cycle of a switching regulator within a temperature range of -55 C to +125 C, and an input voltage range of 10V to 35V. The output-voltage variation was less than + or - 300 parts per million, i.e., less than + or - 3mV for a 10V output

Rational homotopy theory of automorphisms of manifolds

We study the rational homotopy types of classifying spaces of automorphism groups of smooth simply connected manifolds of dimension at least five. We give dg Lie algebra models for the homotopy automorphisms and the block diffeomorphisms of such manifolds. Moreover, we use these models to calculate the rational cohomology of the classifying spaces of the homotopy automorphisms and block diffeomorphisms of the manifold #^g S^d x S^d relative to an embedded disk as g tends to infinity. The answer is expressed in terms of stable cohomology of arithmetic groups and invariant Lie algebra cohomology. Through an extension of Kontsevich's work on graph complexes, we relate our results to the (unstable) homology of automorphisms of free groups with boundaries.Comment: 83 pages. Revision of v2 prompted by referee comments. Final version, to appear in Acta Mathematic

Total-dose radiation effects data for semiconductor devices: 1985 supplement, volume 1

Steady-state, total-dose radiation test data are provided, in graphic format, for use by electronic designers and other personnel using semiconductor devices in a radiation environment. The data were generated by JPL for various NASA space programs. The document is in two volumes: Volume 1 provides data on diodes, bipolar transistors, field effect transistors, and miscellaneous semiconductor types, and Volume 2 provides total-dose radiation test data on integrated circuits. Volume 1 of this 1985 Supplement contains new total-dose radiation test data generated since the August 1, 1981 release date of the original Volume 1. Publication of Volume 2 of the 1985 Supplement will follow that of Volume 1 by approximately three months