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

Buoy Instrumented for Spectral Measurement of Water Quality

An instrumented buoy measures selected aspects of the spectrum of upwelling light for assessment of "water quality." The buoy carries a previously patented optical-backscatter probe that contains a hyperspectral sensor. The output of the probe is processed by a small onboard computer. Cellular-telephone circuitry on the buoy transmits spectral-signature data to a computer system that, in turn, makes the data available immediately over the World Wide Web. Power is supplied by gel batteries charged by a solar photovoltaic panel on top of the buoy. The scalable optical-backscatter probe is a scalable module fabricated separately from the buoy and the other equipment described above; the buoy and the other equipment are designed to accommodate and mate with the optical probe. Optionally, the instrumentation on the buoy can be augmented by incorporation of additional sensors (e.g., a pH sensor current meter). The current version of the buoy is not intended to function in the presence of high wind and waves; it is designed primarily for operation under relatively calm-sea conditions in shallow, semienclosed natural bodies of water (ponds, lakes, lagoons).

Posted in: Briefs, Physical Sciences, Measurements, Water quality, Test equipment and instrumentation

Magnetostrictive Heat Switches Actuated by Flux Tubes

A switch would remain "open" or "closed" until actuated to change its state.

In a proposed improvement on the basic concept of a magnetostrictive heat switch for cryogenic applications, the magnetic field needed for actuation would be generated by a superconducting flux tube (SFT). A closely related concept for a magnetostrictive heat switch was presented in "Magnetostrictive Heat Switch for Cryogenic Use" (NPO-20274), NASA Tech Briefs, Vol. 23, No. 8, (August, 1999), p.48. To recapitulate: The main thermal contact in the heat switch would be made or broken by making or breaking, respectively, the mechanical contact between (1) the moving end of a rod of magnetostrictive material and (2) a fixed contact pad. The magnetic field needed for actuation would be generated by use of a superconducting solenoid.

Posted in: Briefs, TSP, Physical Sciences, Architecture, Switches, Thermal management

Liquid Shell Insulation

At high temperatures and pressures, probes would last just long enough to take readings.

A new concept called "liquid shell insulation" has been proposed as a means of temporary thermal protection for scientific instrument probes that are required to operate for short times in hot, high-pressure environments. Liquid shell insulation was conceived to protect probes that would be dropped from spacecraft to great depths in the atmospheres of the outer planets. For example, at a depth of 1,000 km on Jupiter, a probe would have to withstand a pressure of about 4,000 Earth atmospheres (≈0.4 GPa) and a temperature of about 1,800 K. On Earth, liquid shell insulation might be useful for protecting probes that would be inserted in undersea volcanic vents or deep oil wells.

Posted in: Briefs, TSP, Physical Sciences, Coatings, colorants, and finishes, Heat resistant materials, Insulation, Test equipment and instrumentation

Magnetostrictive Valves Actuated by Flux Tubes

Power would be applied during toggling only.

Magnetostrictive valves for cryogenic applications would be actuated by superconducting flux tubes (SFTs), according to a proposal. The reasoning behind this proposal closely tracks that of the proposal to use SFTs in magnetostrictive heat switches, as reported in the preceding article.

Posted in: Briefs, TSP, Physical Sciences, Sensors and actuators, Valves

Linking Employee Appraisals to Organizational Goals

Evaluation of employee performance would be systematized, centralized, and automated.

The Goal Performance Evaluation System (GPES) is an Internet-based automated management information system (see figure) now undergoing development at Kennedy Space Center (KSC). The GPES is designed to perform two major functions:

Posted in: Briefs, Information Sciences, Internet, Data management, Documentation, Personnel

Program Summarizes Operational Data From a Complex System

Engineering Data Summarization Flight Software is a computer program designed for use aboard a spacecraft to implement a concept, called "beacon monitoring," that has been discussed in several prior NASA Tech Briefs articles. The program generates summaries of operational data (e.g., sensor readings) that represent the state of the spacecraft, and thereby reduces both (1) the quantity of information that must be telemetered to a ground station and (2) the time and cost of analyzing the data to diagnose the spacecraft. The program can also be used to reduce the cost of diagnosing a complex terrestrial system. The program generates event-driven summaries of events since the last contact. For each event, the program identifies the sensor and its readout data that triggered increased monitoring, and gathers data from that sensor and causally related sensors at a high sampling rate around the time of the event. The data from all such events are assigned priorities and stored for downlink at the next telemetry pass. Gaps in the data between events are filled by "snapshots" of all sensor channels sampled at a lower rate. Triggering for each event can be effected by use of either static alarm thresholds or adaptive thresholds established by artificial-intelligence subprograms.

Posted in: Briefs, TSP, Software, Computer software and hardware, On-board diagnostics, On-board diagnostics (OBD), Telemetry, Data management, Spacecraft

Neural-Network Approach to Analysis of Sensor Data

Anomalies in dynamic systems are detected by processing seemingly random time series.

A method of processing of time-series data from sensors that monitor a dynamic physical system has been devised to enable detection of anomalies in the dynamics. The method involves computing what are initially supposed to be dynamical invariants that represent the structural and operational parameters of the system; the invariants are specified in such a way that anomalies or abnormalities in the system manifest themselves as changes in the supposed invariants. The method could be applied, for example, to telemetric data from a spacecraft or to such time-series scientific data as sea-surface temperatures measured at daily or other regular intervals.

Posted in: Briefs, TSP, Information Sciences, Neural networks, Sensors and actuators, Data management

Software for Acquiring Data on Dynamics of Magnetic Bearings

A computer program controls the automated acquisition, display, and reduction of data on the dynamics of magnetic bearings. The data gathered by use of this program are expected to enable the verification and enhancement of mathematical models of magnetic-bearing dynamics, thereby contributing to the development of improved magnetic bearings for advanced gas turbine engines and other rotary machines.

Posted in: Briefs, TSP, Software, Mathematical models, Computer software and hardware, Magnetic materials, Bearings, Gas turbines, Rotary engines

Fluorometer for Analysis of Photosynthesis in Phytoplankton

Measurements could be made in situ and in vivo.

An instrument that measures the characteristic lifetime of fluorescence of chlorophyll has been invented for in situ, real-time oceanographic studies of photosynthesis in phytoplankton. The basic design and principle of operation lend themselves to development of the instrument as a relatively inexpensive, sensitive, compact, rugged, portable, low-power-consumption, hand-held, shipboard unit. Similar units with designs adapted to agricultural applications (e.g., assessment of physiological statuses of crops) are also envisioned.

Posted in: Briefs, TSP, Physical Sciences, Biological sciences, Test equipment and instrumentation, Marine vehicles and equipment

Program for Visualization and Exploration of Scientific Data

WebWinds is an interactive computer program that aids the visualization and exploration of scientific data. WebWinds is the successor to LinkWinds, which was reported in "LinkWinds — Flexible Software for Highly Interactive Visual Data Analysis" (NPO-19786), NASA Tech Briefs, Vol. 20, No. 12 (December 1996), page 46. WebWinds is a platform-independent, reusable code written in the Java computer language. WebWinds has been tested on Linux, Sun, SGI, and Win95 systems.

Posted in: Briefs, TSP, Information Sciences, Computer software and hardware, Imaging and visualization, Data management

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