Special Coverage

Converting from Hydraulic Cylinders to Electric Actuators
Automating Optimization and Design Tasks Across Disciplines
Vibration Tables Shake Up Aerospace and Car Testing
Supercomputer Cooling System Uses Refrigerant to Replace Water
Computer Chips Calculate and Store in an Integrated Unit
Electron-to-Photon Communication for Quantum Computing
Mechanoresponsive Healing Polymers
Variable Permeability Magnetometer Systems and Methods for Aerospace Applications
Evaluation Standard for Robotic Research

Improvements in Computed-Tomography Imaging Spectrometry

CGHs are used for dispersion, and a modified calibration procedure saves time.

Two major improvements, described below, have been made in the construction and operation of a computed-tomography imaging spectrometer (CTIS). These plus future improvements can be expected to enhance the practicality and commercial viability of CTISs, which, in principle, offer unprecedented capabilities for imaging with spatial, spectral, and temporal resolution. For example, the CTIS in its present form could be used in medical and pharmaceutical applications to perform spectral imaging of transient scenes that contain fluorescent dyes. With increases in spectral accuracy and spatial resolution, it could be used for remote sensing.

Posted in: Briefs, Physical Sciences, Remote sensing, Spectroscopy, Medical equipment and supplies, Performance upgrades

Program for Displaying Large, Coregistered Images

DataSlate is an easy-to-use Java-language computer program for displaying coregistered raster images representing large sets of data. The program includes a main viewing module that can display image data that have been converted into a special DataSlate format called "SimpleStruct" by use of an Interactive Data Language program called "SimpleGen." The conversion into SimpleStruct optimizes the organization of the data in the sense that it simplifies any computations that must be done subsequently during perusal of the data. DataSlate enables the user to navigate very large sets of scientific data visually: DataSlate presents a slatelike user interface with simple buttons to select sets of data or to zoom in or out. The user can scroll through a set of data by simply dragging a cursor on a screen. DataSlate can also dynamically load plug-in software tools (e.g., for measuring lengths, angles, areas, or geographic coordinates) at run time. DataSlate can also traverse coregistered collections of data and can present a second data channel in a window on the screen to facilitate correlation or comparison of two sets of data (e.g., from two sensors and/or taken at different times).

Posted in: Briefs, Information Sciences, Computer software and hardware, Imaging and visualization, Human machine interface (HMI), Data management

GA Synthesis of Circuits Using a Linear Representation

The procedure for designing many practical circuits can be partly automated.

A method of automated synthesis of electronic circuits involves the use of a linear (as defined below) genome representation of circuit elements and of connections among them, plus a relatively simple unfolding technique, in conjunction with a genetic algorithm (GA). The method differs from most other GA-based circuit-synthesis methods in that the topology of a circuit, the number of its components, and the types and values of its components (e.g., inductances, capacitances, and resistances) are all made to evolve by use of the GA.

Posted in: Briefs, Electronics & Computers, Mathematical models, Architecture, Electronic control systems

Silicon Carbide npnp Thyristors

These devices can be operated at temperatures up to 350 °C.

Thyristors (semiconductor controlled rectifiers) made from silicon carbide have been fabricated and tested as prototypes of power-switching devices capable of operating at temperatures up to 350 °C. The highest-voltage-rated of these thyristors are capable of blocking current at forward or reverse bias as large as 900 V, and can sustain forward current as large as 2 A with a forward potential drop of –3.9 V. The highest-power-rated of these thyristors (which are also the highest-power-rated SiC thyristors reported thus far) can block current at a forward or reverse bias of 700 V and can sustain an "on" current of 6 A at a forward potential drop of –3.67 V. The highest-current-rated of these thyristors can block current at a forward or reverse bias of 400 V and can sustain an "on" current of 10 A.

Posted in: Briefs, Electronics & Computers, Architecture, Semiconductor devices, Switches

Small Lidar Altimeter Would Operate at Low Light Levels

Relatively high resolution would be achieved without resorting to high power.

A lidar apparatus called a microaltimeter has been proposed for use aboard a spacecraft in orbit around the Earth for mapping land and sea surfaces, including such features of special interest as ice, tree canopies, and flood plains. The microaltimeter is short for "microlaser altimeter" and is so named because it uses a very compact, low-energy, subnanosecond pulse, solid-state microlaser as its source and relatively small (typically 10 to 20 cm in diameter) telescopes, resulting in a factor of 100 reduction in telescope weight and volume, as compared to conventional spaceborne laser altimeters. Operating at thousands of pulses per second, the surface sampling rate is approximately 100 times higher than that of prior spaceborne laser altimeters having the same transmitter power-aperture product.

Posted in: Briefs, Electronics & Computers, Altimeters, Cartography, Lidar, Spacecraft

Improved Methods of Testing Cryogenic Insulation Materials

Specimens are easy to fabricate, and thermal performance measurements are repeatable.

Two improved methods have been developed for testing continuously rolled blankets and blanketlike thermal-insulation materials typically used in cryogenic vacuum systems. Both methods, and their corresponding apparatuses, are based on the cryogen boiloff calorimeter method according to which the amount of heat that passes through an insulation specimen to a cryogenic fluid in a vessel is proportional to the rate of boiloff from that vessel. The boiloff rate is then directly related to the insulating performance of the specimen. The main challenges in the execution of this technique are to (1) eliminate (or minimize) heat leak from the ends by use of thermal guards and (2) obtain stability of the cryogen inside the measurement vessel coincident with stability of the boundary conditions in the vacuum space.

Posted in: Briefs, TSP, Test & Measurement, Insulation, Textiles, Test procedures

Real-Time Optoelectronic Particle-Fallout Monitors

These instruments would extract quantitative data from images of particles.

Optoelectronic instruments for real-time, in situ monitoring of particle fallout are undergoing development. Settings in which these instruments could prove useful include clean rooms for assembly of optical and electronic equipment, food-packaging facilities, and other industrial facilities in which one seeks to prevent contamination of products by airborne dust and fibers.

Posted in: Briefs, Test & Measurement, Optics, Particulate matter (PM), Test equipment and instrumentation

Program for Controlling Digital Instrumentation Recorders

A computer program enables the simultaneous monitoring and control of two commercial digital instrumentation recorders, each comprising a variable-rate buffer and a data tape recorder. The program can issue all standard tape-motion-related commands (fast forward, rewind, record, forward, reverse, and eject) plus commands for tape search, time code, and buffer settings. The program provides a graphical user interface that facilitates control by the user and displays the operational statuses of the buffers and tape recorders. The program generates a log file that includes a time and date stamp for each control command sent to, and response received from, each buffer and recorder. An option exists in the program to produce tape copies by dubbing from one recorder to the other. The program can also be used to effect a procedure in which data are recorded first on one tape recorder, then the other tape recorder is brought into operation shortly before the end of first tape, so that there is some overlap to ensure continuous recording during a long recording session.

Posted in: Briefs, Test & Measurement, Computer software and hardware, Human machine interface (HMI), Displays, Test equipment and instrumentation

Program Computes Tone Fan Noise From a Turbofan Engine

TFaNS is a computer program that predicts the tone noise that emanates from the fan stage of a turbofan engine. With the help of this program, engineers working to reduce fan tone noise can study the effects of proposed design changes and are thus more likely to be successful in their efforts.

Posted in: Briefs, Software, Sound quality, Fans, Turboprop engines

Software for Generating 100-by-100-km Images From SAR Data

SAR Processing System Precision Processor (SPS PP) is one of the computer programs used in the Alaska SAR Facility (ASF) [where "SAR" means "synthetic-aperture radar"] to generate image data products. SPS PP ingests data that have been received from the RADARSAT (a Canadian Earth-observation satellite) and decoded into engineering and SAR signal data files, and processes these data into image data products that typically cover areas of about 100 km by 100 km. SPS PP can handle data from RADARSAT standard right- and left-looking beams, and is being enhanced to handle European Remote Sensing Satellite (ERS) and Japanese Earth Resources Satellite (JERS) data. The output of SPS PP conforms to the standards of the Committee on Earth Observing Satellites (CEOS). The left-looking products feature 16-bit detected pixels in slant-range format; the right-looking products can be in either ground-range detected or slant-range complex format. SPS PP resides on five IBM SP-2 computers with 8 processing nodes each. Each computer can produce a 100-by-100-km image frame in about 25 minutes.

Posted in: Briefs, TSP, Software, Computer software and hardware, Imaging and visualization, Radar, Satellites

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