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Displaying 51501 - 51525 of 73697

Algorithms for Fresnel Diffraction at Rectangular and Circular Apertures

September 1, 1998
Author(s)
Klaus Mielenz
This paper summarizes the theory of Fresnel diffraction by plane rectangular and circular apertures with a view toward numerical computations. Approximations found in the earlier leterature, and now obsolete, have been eliminated and replaced by algorithms

Anisotropy of Interfaces in an Ordered HCP Binary Alloy

September 1, 1998
Author(s)
John W. Cahn, S C. Han, Geoffrey B. McFadden
A multiple-order parameter mean field theory of ordering on a binary hexagonal-close-packed (HCP) crystal structure is developed, and adapted to provide a continuum formulation that incorporates the underlying symmetries of the HCP crystal in both the bulk

Are the Formulas for Mode-Field Diameter Correct?

September 1, 1998
Author(s)
Ronald C. Wittmann, M. Young
We have found conceptual problems with the far-field formula 1 for mode field diameter First, the formulation is incomplete in that it ignores the obliquity factor; second, it assumes that the field at the end of a truncated fiber is identical to the mode

Basic Concepts and Methods for Keeping Autonomous Ground Vehicle Formations

September 1, 1998
Author(s)
Yigal Moscovitz, Nicholas DeClaris
A desirable basic behavior of a group of autonomous vehicles while in motion is to keep a predefined formation. Normally units are trained to move in formation according to an operational status. Past experience determines the formation for given

Case Against Optical Gauge Block Metrology

September 1, 1998
Author(s)
Theodore D. Doiron, Dennis S. Everett, Bryon S. Faust, Eric S. Stanfield, John R. Stoup
The current definition of length of a gage block is a very clever attempt to evade the systematic errors associated with the wringing layer thickness and optical phase corrections. In practice, there are very large systematic operator and surface effects

Collaborating on the Design and Manufacture of an Atomic Artifact Transport System: A Case Study in VRML as a Visualization Tool for Consensus Building

September 1, 1998
Author(s)
Robert Allen, Srinivas Nidamarthi, P V. Rao, Richard L. Rhorer, Ram D. Sriram, E C. Teague
We report on our experience using the Virtual Reality Markup Language (VRML) to collaborate on the design and manufacture of an artifact transport system (ATS). Specifically designed for the purpose of transporting nanometer-scale dimensional artifacts at

Crystal Structure of Strontium Potassium Arsenate Octahydrate

September 1, 1998
Author(s)
M Mathew
The crystal structure of strontium potassium arsenate octahydrate, SrKAsO 4.8H 2O, has been determined by single crystal x-ray diffraction. The crystals are tetragonal, a = 7.144(1){Angstrom}, c = 23.613(2){Angstrom}, space group I4 1md (No. 109), Z = 4, V

Design of a Novel Fixture for Part Referencing

September 1, 1998
Author(s)
Walter W. Nederbragt, Bahram Ravani
This paper presents a novel design for a practical tactilesensing mechanical fixture. The fixture consists of two tactilesensing surfaces, a cylindrical surface and a planar surface. A mathematical procedure is developed for constructing a reference frame

Effect of Heating Rate and Grain Size on the Melting Behavior of the Alloy Nb-47 Mass% Ti in Pulse-Heating Experiments

September 1, 1998
Author(s)
D Basak, William J. Boettinger, Daniel Josell, Sam R. Coriell, J L. McClure, Sitaraman Krishnan, A Cezairliyan
The effect of heating rate and grain size on the melting behavior of Nb-47 mass % Ti is measured and modeled. The experimental method uses rapid resistive self-heating of wire specimens at rates between -10 2 and -10 4 K/s and simultaneous measurement of

Electroacoustic Analysis in Processing of Advanced Ceramics

September 1, 1998
Author(s)
Vincent A. Hackley, U Paik
Finely dispersed systems such as emulsions and colloidal suspensions are recognized as playing a critical role in many important industrial processes. Many of these systems are quite concentrated, and significant needs exist to develop measurement
Displaying 51501 - 51525 of 73697
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