A proposed x-ray instrument - a Fourier-transform x-ray microscope - would enable high-resolution imaging of objects with sizes of the order of 20 nm. (This size range is typical of cell organelles.) The instrument would also offer a spectroscopic capability for the sensitive detection and identification of...

AMPERES is a prototype computer program that implements the algorithm, described in the preceding article, for optimizing designs of diffractive optics. Several other programs for designing refractive optics are commercially available, but they offer very limited capabilities with respect to...

An algorithm for optimizing the designs of diffractive optics is based on constrained dynamics and the reciprocity of electromagnetic propagation. This algorithm can contribute to realization of the potential of diffractive optics, which offer capabilities greater than those of refractive...

Sensors based on microscopic optical resonators and arrays of such resonators have been proposed for detecting trace amounts of specific molecules in small gaseous, liquid, and solid samples. In addition to compactness, these sensors would offer ultrahigh sensitivity - in some cases, enough...

Solar heating has been proposed as a means of deployment of structures of the type described in "Cold Hibernated Elastic Memory (CHEM) Expandable Structures," (NPO-20394), NASA Tech Briefs, Vol. 23, No. 2 (February 1999), page 56. A few examples of structures that would be amenable to the CHEM...

Some experiments directed toward the development of improved hard, lubricious coating materials have involved direct fluorination of proprietary diamondlike coats on various substrates. The idea is to retain the hardness of the diamondlike material while adding surface molecular structures that impart the...

The YaM computer program provides a conceptual framework (including configuration management) and a set of software tools that support the concurrent development of reusable software by members of a team. YaM favors development of software in modules that can be assembled into packages and...

A computer program implements an adaptive problem-solving (APS) algorithm for real-time development, refinement, and maintenance of the control strategy of an autonomous system that must operate in an environment about which little or no detailed information is available in advance. In the...

Recent improvements in the SINDA/FLUINT computer program have made the program into a highly capable, commercially viable software product for general mathematical modeling of thermohydraulic systems. Versions of SINDA/FLUINT have been described in a number of previous NASA Tech Briefs...

This test automation software reduces the burden of testing artificial-intelligence (AI) planning software written in the Heuristic Scheduling Testbed System (HSTS) [a software architecture for planning and scheduling]. It automates what would otherwise be the labor intensive and infeasibly...

A computational fluid dynamics (CFD) code has been developed to enable simulation of spray combustion near the fuel injectors in a liquid-fueled rocket engine. This code reflects the three-dimensional (3D), multiphase nature of the flow field in a rocket engine and is capable of modeling...

An improved automated system for transferring liquid helium from a supply tank to an end-use cryostat has been proposed. Like automated systems developed previously for the same purpose, this system would reduce the time that must be spent by technicians in replenishing cryostats in equipment...

The Newton-Euler Inverse Mass Operator (NEIMO) algorithm and software that implements the algorithm have been developed to reduce the amount of time needed to perform computational simulations of the dynamics of macromolecules. The NEIMO algorithm and the associated software are intended, in particular,...

A proposal has been made to develop improved thin foil, replicated conical mirrors for use in x-ray astrophysics. In the NASA astrophysical programs in which such mirrors are used, they are required to be lightweight, and to offer moderate angular resolution and high throughput to afford required sensitivity in the...

A query timeout detection algorithm has been proposed to support a protocol for reliable communications over links that are characterized by long delays because of (1) propagation of signals over interplanetary distances and/or (2) intermittency. The protocol could be an interplanetary analogue...

A report proposes that solar sails for spacecraft be made from nets of carbon fibers. The reason for choosing carbon nets over thin polymeric films is that nets offer greater capability for carrying tensile loads. The sails could be made from carbon-fiber nets of various thicknesses: nets used for...

A report proposes that solar sails for spacecraft be constructed in segments in such a way as to minimize stresses. The segments could be made of metallized fabric or film and could be connected by short, strong tethers. Alternatively, the segments could be like islands, held loosely in...