Special Coverage

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
Small Robot Has Outstanding Vertical Agility
Smart Optical Material Characterization System and Method
Lightweight, Flexible Thermal Protection System for Fire Protection
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Model Simulates Semi-Solid Material Processing

Processing materials in the semi-solid state has many advantages over conventional processing methods.David Spencer (MIT) developed semi-solid material processing through an accidental observation he made while dealing with the processing of metals in their mushy state. The semi-solid material process basically consists of two stages: pre-processing and processing. During pre-processing, the manufacturer heats the material to a liquid state. While it cools, the manufacturer breaks the material up, usually by mechanical means. The result is a mushy material with a very uniform microstructure consisting mainly of round crystals. Then, in the processing stage, the manufacturer forces the mushy material into a die where it is allowed to fully cool.

Posted in: Briefs, Materials, Simulation and modeling, Casting, Manufacturing processes, Materials properties, Metals

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Modular Cryogenic Insulation

Principal advantages are long life and low density."Modular cryogenic insulation" denotes a chaff for installation in the partially evacuated annular spaces between the inner and outer walls of tanks used to store and transport liquid nitrogen and other cryogenic liquids. The insulating chaff was developed to replace low-density powders (e.g., perlite, silica aerogel, carbon black, or diatomaceous earth) that have been used to insulate cryogenic tanks. Thermal cycling of a tank causes some of the powder to fall to the bottom of the annular space; over time, the powder accumulates in the bottom and becomes compacted there, with consequent loss of thermal-insulation performance. In addition, the compaction generates stresses that can damage the tank. The chaff was selected from among several candidate materials that were investigated to find one that would not settle with thermal cycling, would be readily manufacturable, would offer the requisite thermal-insulation performance, would thermally expand and contract along with the tank walls, and could be installed easily.

Posted in: Briefs, Materials, Containers, Storage, Insulation

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Passive Venting for Alleviating Helicopter Tail-Boom Loads

Preliminary results indicate that venting could be used to advantage. The tail boom of a single-rotor helicopter is subjected to a complex flow field that includes the wakes of the main and tail rotors, the freestream, and the wake from the forward fuselage. Hovering and sideward flight present the operational regimes that are most critical with respect to adverse sideward and downward loads on the tail boom. These adverse loads necessitate additional engine power, thereby reducing payload, performance, and available yaw-control margins. In addition, nonlinear side-force gradients near conditions of boom stall can make precise yaw control very difficult for the pilot. The addition of strakes to the tail boom is one method that has been used to modify the flow field and reduce these adverse loads.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Aircraft Tails, Rotary-wing aircraft

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Computer Program Predicts Rocket Noise

Parameters and configurations can be varied as needed.A computer program predicts the noise and ignition over pressure in the vicinity of a rocket during launch. The program has been developed to complement the vibroacoustic-prediction effort for rockets now in use and to provide the capability for prediction of vibroacoustic loads associated with next-generation rockets. Programs like this one are vital parts of the implementation of NASA's "better, faster, cheaper" philosophy; they are needed because full-scale acoustic and vibration testing of launch vehicles or payloads is often difficult, time-consuming, and prohibitively expensive.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Computer software and hardware, Acoustics, Vibration, Rocket engines, Entry, descent, and landing

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External Adhesive Pressure-Wall Patch

A hole in a pressure wall can be patched, without need for previously installed faste A mechanical device has been developed for applying an adhesive patch, from the outside, to the wall of a spacecraft module that has lost pressure because of penetration by a meteoroid or a piece of orbital debris. This device will make it possible to seal and re-pressurize the affected module during space flight. Devices identical or similar to this one might also prove useful in the repair of other pressurized bodies and similar objects, including gas and oil pipes and ship hulls, for example.

Posted in: Briefs, Manufacturing & Prototyping, Tools and equipment, Adhesives and sealants, Spacecraft

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Java Implementation of Information-Sharing Protocol

The Java-language ISPresso software enables real-time access to mission data via home and office personal computers. Johnson Space Center's (JSC's) growing operations community requires new ways to distribute and process mission information. The Mission Control Center uses flight-control application programs based on an information-sharing protocol (ISP) to process and distribute real-time mission telemetry, trajectory, and computation data. ISP application programs provide multiple users synchronous, rapid access to mission data and programs. The ISPresso ISP software package is designed in Java, which is rapidly becoming the language of choice because of its ability to work on almost any platform. ISPresso plays a substantial role in the remote-access platforms now being implemented for space-shuttle and space-station operations and is used for Hubble Space Telescope operations. The portability of ISPresso enables deployment of mission-data-processing application programs to desktop computers and makes it possible to package application software for convenient access through web browsers. Such accessibility will prove useful in many additional process-control settings, from powerplants to all types of manufacturing.

Posted in: Briefs, Information Sciences, Communication protocols, Computer software and hardware, Spacecraft

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Electronic Bulletin Board Publishes Schedules in Real Time

Real Time Schedule Publisher (RTSP) is a computer program that generates a report of the current schedules of as many as about 25 users within an organization. The report is refreshed every 5 minutes and displayed in a common area on a flat-panel computer monitor that serves as an "in/out" bulletin board. The report is displayed in a five-column tabular format and includes color-coded legends that describe the status (with respect to availability) of each user. Each row of the table reflects a single event for a single user; the five columns represent, respectively, the name of the user, the event start time, the event end time, the location, and the subject. The display also includes the current date, day of the week, and time. In addition to the common display, an interactive view of the scheduling information is available, through a standard web browser, on any desktop computer connected to the organization's computer network. The interactive view provides an interface for administering users' accounts. RTSP is based on the active-server architecture of the Windows NT Server operating system and is integrable with similarly based commercial-off-the-shelf scheduling programs.

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

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