2,756 research outputs found

    GRAIL – Grid Access and Instrumentation Tool

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    Since the release of Globus Toolkit 4 Web services enrich the world of Grid Computing. They provide methods to develop modular Grid applications which can be parallelized easily. The access to Web services is mostly solved by complex command line tools which need a good deal of knowledge of the underlaying Grid technologies. GRAIL is intended to fill the gap between existing Grid access methods and both the developer who wants to utilize the Grid for own developments and the user who wants to access the Grid without much additional knowledge. It simplifies the access and the testing of Web services for the Globus Grid middleware. GRAIL provides an easy to use graphical user interface for executing Web services and enables the user to construct complex relationships between services to realize parallel execution. The underlying framework allows an easy integration of any Web service or other arbitrary task without much additional effort for the developer. Existing technologies, shipped with the Globus Toolkit, are seamlessly integrated into GRAIL

    Parametric infrared tunable laser system

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    A parametric tunable infrared laser system was built to serve as transmitter for the remote detection and density measurement of pollutant, poisonous, or trace gases in the atmosphere. The system operates with a YAG:Nd laser oscillator amplifier chain which pumps a parametric tunable frequency converter. The completed system produced pulse energies of up to 30 mJ. The output is tunable from 1.5 to 3.6 micrometers at linewidths of 0.2-0.5 /cm (FWHM), although the limits of the tuning range and the narrower line crystals presently in the parametric converter by samples of the higher quality already demonstrated is expected to improve the system performance further

    Oblique stacking of three-dimensional dome islands in Ge/Si multilayers

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    The organization of Ge "dome" islands in Ge/Si multilayers has been investigated by cross-sectional transmission electron microscopy. Ge domes are found to spontaneously arrange in oblique stacks, replicating at a well-defined angle from one bilayer to the next. The formation of oblique island stacks is governed by a complex interplay of surface strain, generated by the already buried islands, and surface curvature, caused by the inherent tendency of large domes to carve out material from the surrounding planar substrate. (C) 2001 American Institute of Physics

    Structurally adaptive space crane concept for assembling space systems on orbit

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    Many future human space exploration missions will probably require large vehicles that must be assembled on orbit. Thus, a device that can move, position, and assemble large and massive spacecraft components on orbit becomes essential for these missions. A concept is described for such a device: a space crane concept that uses erectable truss hardware to achieve high-stiffness and low-mass booms and uses articulating truss joints that can be assembled on orbit. The hardware has been tested and shown to have linear load-deflection response and to be structurally predictable. The hardware also permits the crane to be reconfigured into different geometries to satisfy future assembly requirements. A number of articulating and rotary joint concepts have been sized and analyzed, and the results are discussed. Two strategies were proposed to suppress motion-induced vibration: placing viscous dampers in selected truss struts and preshaping motion commands. Preliminary analyses indicate that these techniques have the potential to greatly enhance structural damping

    Structural characterization of a first-generation articulated-truss joint for space crane application

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    A first-generation space crane articulated-truss joint was statically and dynamically characterized in a configuration that approximated an operational environment. The articulated-truss joint was integrated into a test-bed for structural characterization. Static characterization was performed by applying known loads and measuring the corresponding deflections to obtain load-deflection curves. Dynamic characterization was performed using modal testing to experimentally determine the first six mode shapes, frequencies, and modal damping values. Static and dynamic characteristics were also determined for a reference truss that served as a characterization baseline. Load-deflection curves and experimental frequency response functions are presented for the reference truss and the articulated-truss joint mounted in the test-bed. The static and dynamic experimental results are compared with analytical predictions obtained from finite element analyses. Load-deflection response is also presented for one of the linear actuators used in the articulated-truss joint. Finally, an assessment is presented for the predictability of the truss hardware used in the reference truss and articulated-truss joint based upon hardware stiffness properties that were previously obtained during the Precision Segmented Reflector (PSR) Technology Development Program

    Architecture of the Grid Services Toolkit for Process Data Processing

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    Grid is a rapidly growing new technology that will provide easy access to huge amounts of computer resources, both hardware and software. As these resources become available soon, more and more scientific users are interested in benefiting from them. At this time the main problem accessing the Grid is that scientific users usually need big knowledge of Grid methods and technologies besides their own field of research. To fill the gap between high-level scientific Grid users and low-level functions in Grid environments the Grid Services Toolkit (GST) is developed at the IPE. Aimed to simplify and accelerate the development of parallelized scientific Grid applications, the GST is based on Web services extended by a rich client API. It is especially designed for the field of process data processing providing database access and management, common methods of statistical data analysis and project specific methods

    Protoptype integrated design (Pride) system reference manual. Volume 2: Schema definition

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    An initial description of an evolving relational database schema is presented for the management of finite element model design and analysis data. The report presents a description of each relation including attribute names, data types, and definitions. The format of this report is such that future modifications and enhancements may be easily incorporated
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