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Earth Observing System Data Gateway

The Earth Observing System Data Gateway (EDG) software provides a “onestop-shopping” standard interface for exploring and ordering Earth-science data stored at geographically distributed sites. EDG enables a user to do the following:

Posted in: Briefs, TSP

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Mercury Shopping Cart

Mercury Shopping Cart Interface (MSCI) is a reusable component of the Power User Interface 5.0 (PUI) program described in the immediately preceding article. MSCI is a means of encapsulating the logic and information needed to describe an orderable item consistent with Mercury Shopping Cart service protocol. Designed to be used with Web-browser software, MSCI generates Hypertext Markup Language (HTML) pages on which ordering information can be entered. MSCI comprises two types of Practical Extraction and Report Language (PERL) modules: template modules and shopping-cart logic modules. Template modules generate HTML pages for entering the required ordering details and enable submission of the order via a Hypertext Transfer Protocol (HTTP) post. Shopping-cart modules encapsulate the logic and data needed to describe an individual orderable item to the Mercury Shopping Cart service. These modules evaluate information entered by the user to determine whether it is sufficient for the Shopping Cart service to process the order. Once an order has been passed from MSCI to a deployed Mercury Shopping Cart server, there is no further interaction with the user.

Posted in: Briefs, TSP

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Cassini Archive Tracking System

The Cassini Archive Tracking System (CATS) is a computer program that enables tracking of scientific data transfers from originators to the Planetary Data System (PDS) archives. Without CATS, there is no systematic means of locating products in the archive process or ensuring their completeness. By keeping a database of transfer communications and status, CATS enables the Cassini Project and the PDS to efficiently and accurately report on archive status. More importantly, problem areas are easily identified through customized reports that can be generated on the fly from any Web-enabled computer. A Web-browser interface and clearly defined authorization scheme provide safe distributed access to the system, where users can perform functions such as create customized reports, record a transfer, and respond to a transfer. CATS ensures that Cassini provides complete science archives to the PDS on schedule and that those archives are available to the science community by the PDS. The three-tier architecture is loosely coupled and designed for simple adaptation to multi-mission use. Written in the Java programming language, it is portable and can be run on any Java-enabled Web server.

Posted in: Briefs, TSP

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Computing Fault Displacements From Surface Deformations

Simplex is a computer program that calculates locations and displacements of subterranean faults from data on Earth-surface deformations. The calculation involves inversion of a forward model (given a point source representing a fault, a forward model calculates the surface deformations) for displacements, and strains caused by a fault located in isotropic, elastic half-space. The inversion involves the use of nonlinear, multi-parameter estimation techniques. The input surface-deformation data can be in multiple formats, with absolute or differential positioning. The input data can be derived from multiple sources, including interferometric synthetic-aperture radar, the Global Positioning System, and strain meters. Parameters can be constrained or free. Estimates can be calculated for single or multiple faults. Estimates of parameters are accompanied by reports of their covariances and uncertainties. Simplex has been tested extensively against forward models and against other means of inverting geodetic data and seismic observations.

Posted in: Briefs, TSP

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Alternatives to Keyways in Motion Systems

The age-old tradition of using shaft keys in mechanical drives has served the power transmission industry well for many years. When appropriately sized, it guarantees that virtually no relative motion can take place between a shaft and its respective shaft hub in a unidirectional continuous motion application. Today’s increasing demands for speed, precision, and small size have changed the standard for shaft locking devices, and challenged motion components manufacturers to develop new methods of keyless shaft locking for dynamic loading. As motors and drives become increasingly capable of rapid acceleration and rotary positioning accuracy in smaller and smaller packages, backlash, stress distribution, and balance have all needed to be addressed in shaft locking devices, in many cases rendering the shaft key obsolete.

Posted in: Features, Articles

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Actuator Controls Valving in Micro-Satellite Thruster

In the 1980s and 1990s, NASA’s Jet Propulsion Laboratory (Pasadena, CA) began developing advanced microsystems and microelectronics technologies and components for future space applications. One of these experimental designs, the Micro-Inspector Spacecraft, is capable of visual inspection of a host space vehicle with support from NASA’s Exploration Systems Mission Directorate. The piezoelectric actuator in the Micro-Inspector’s propulsion system is from Dynamic Structures and Materials (DSM, Franklin, TN), and controls the many valves of the satellite’s engines.

Posted in: Applications, Application Briefs

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Fiber Optic Rotary Encoder Helps Guide Aerial Tramways

In situations where human travel is necessary but where the geography is too steep or treacherous, aerial tramways often are used as a convenient alternative. Ski resorts, mountaineering centers, even archeological sites and cities with a diverse geography have tapped tramways as a method of transportation. When FREY AG (Stans, Switzerland) began constructing new aerial tramway systems, it turned to Micronor’s (Newbury Park, CA) fiber optic MR314 ZapFree™ high resolution hollow shaft rotary encoder to be part of the tramway’s positioning and cable systems.

Posted in: Applications, Application Briefs

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