Capability Of Analytical Models Research Articles

The Role of Spatial Decision Support System in Regional Business Spatial Community

Decision support systems are tools that extend the functionality of management information systems. Similarly, spatial decision support systems (SDSS) enhance the capabilities of geographic information systems (GIS) with analytical modelling capabilities and support processes of spatial decision making. SDSS offer many kinds of spatial analyses, from processing data (as well spatial as other data residing in databases), do intelligent maps and models of different types of phenomena. Regional Busines Spatial Community (RBSC) is the concept of community gathering units responsible for building infrastructure networks and supplying utilities for citizens of a region.The authors try to create the community on the basis of companies and institutions from the territory of the City of Częstochowa. A commonality of all the aforementioned stakeholders is to be the possibility to participate in the shared SDSS with the purpose of planning infrastructure investments on the territory of the city. This paper aims to examine the functionality of accessible GIS and to indicate how they can be enhanced with analytical modeling capabilities for the needs of the considered community.

Advanced materials for space structures

Potential space structures of the future will have extremely demanding goals in performance, reliability, and affordability. When compared to previous space systems, these systems will require greater accuracy/dimensional stability, longer life, greater survivability to both natural and threat environments, and producibility capability for high volume production. In order to achieve the goals in these areas, advances will be needed in materials and structural concepts. Under a program managed by the Wright Research and Development Center at Wright-Patterson AFB, Ohio, several key material areas have been selected for technology development and validation. These include tribomaterials, structural materials, and materials and techniques for dynamic control of space structures. Tribomaterials efforts involve improvements in bearings, lubricants, and similar materials to provide long life and high accuracy for moving mechanical assemblies, such as gimbals, reaction wheels, and solar array drives. Structural materials programs involve, primarily, reinforced metallic and nonmetallic composites for improvements in performance, weight reduction, and cost reduction. The third area, dynamic control of space structures, involves both active and passive damping, as well as analytical modeling capabilities, to achieve system stability necessary to meet accuracy requirements. Technologies being developed in these areas are considered generic to Space Systems. Materials are being developed either in advance or parallel to systems development in order to provide critical technologies prior to major system design decisions or to reduce systems risk, by providing alternative materials and structures for improved performance, weight reduction, or cost reduction over identified system baseline designs. In order to be cost efficient, maximum effort is extended to leveraging off materials technology development in the aircraft industry and by taking advantage of technology existing in the United Kingdom of Great Britain. Program efforts in these areas concentrate on extending the data base, addressing specific space environmental conditions, and in demonstrating generic product forms for space applications. Specific materials included in the overall program will be covered, and anticipated advantages of the materials will be presented. Product forms fabricated to date and mechanical properties will be presented. In order to qualify these materials for space applications, structural validation programs will be conducted. Potential structural validation programs such as stabilized solar arrays, light weight-stable optical benches and improved thermal radiators will be identified, along with the materials proposed for use in these applications. Anticipated payoffs for these applications will be covered.

Modeling of a Shape Memory Integrated Actuator for Vibration Control of Large Space Structures

Martin Marietta is developing a shape memory material actuator to pro vide active vibration and shape control for large, adaptive space structures. An important facet of this work is the development of analytical modeling capabilities for shape memory material behavior. These alloys exhibit a very interdependent force-length-temperature (FLT) response, which must be understood to best exploit their behavior for the efficient and timely conversion of heat into mechanical work. Also, the modal response of large, flexible space structures will be affected by the use of inherently non-linear, hysteretic shape memory actuators, and specialized control methodologies need to be developed spe cific to this application. In this work, Cory and McNichols' theory of non-equilibrium thermostatics (NET) was modified to account for the multiple quadrant (i.e., tension and compression) hysteretic behavior of shape memory alloys. Experimental results were used to provide the basis for spatial mapping of the austenite-to-martensite ( AM) and mar tensite-to-austenite ( MA) phase transformation boundaries, along with the relative loca tions of the 100% austenite ( ZA) and 100% aligned martensite ( ZM) saturation surfaces in the three-dimensional FLT material behavior domain. A Fortran subroutine, describing the shape memory material actuator, was incorporated into dynamic analyses of a simpli fied finite element model based on the Spacecraft Control Laboratory Experiment (SCOLE) structure. A slewing maneuver of 20 degrees in 12 seconds was used to study a number of cases for the shape memory actuator which utilized a biasing force (e.g., the biasing effect of a matrix in a strain-compliant shape memory composite) acting against 150 NiTi wires (0.5 mm dia. by 0.50 m in length). Temperature was used as the command variable to demonstrate active vibration control during and after the slew maneuver. Sig nificant passive damping was noted, in addition to effective active control when the actua tor's temperature was pulsed. This analytic "test bed" will provide critical insight into the design and analysis of smart, adaptive shape memory space truss tubes and actuators for vibration and shape control, as well as the vehicle by which future shape memory actuator control algorithms and methodologies can be assessed.

Boiling Water Reactor Loss of Coolant Tests Single Failure Tests with ROSA-III

The single failure tests with the ROSA-III were simulated BWR LOCA experiments by the scaled BWR test facility resulting from a 200% double-ended break at the recirculation pump suction line to evaluate the core cooling capability of a BWR ECCS under the single failure condition. The experimental results showed that the loss of LPCS and one LPCI resulted in the highest PCT of 870 K of the single failure series tests, yet a core cooling capability by the ECCS was maintained. The REALP4/Mod 6 code was used to evaluate the predictive capability of the LOCA analysis code. The calculated results showed that the RELAP4/Mod 6 code was able to predict occurrences and sequence of major events anticipated to occur during a BWR LOCA correctly. However it was found that the code still needs to be improved in a CCFL model to better describe thermohydraulic behavior in the core. The analyses presented in this paper are valuable for evaluating the adequacy and improving the predictive capability of analytical models developed to predict the system response of a BWR during a LOCA.

Boiling water reactor loss of coolant tests. Single failure tests with ROSA-III.

The single failure tests with the ROSA-III were simulated BWR LOCA experiments by the scaled BWR test facility resulting from a 200% double-ended break at the recirculation pump suction line to evaluate the core cooling capability of a BWR ECCS under the single failure condition. The experimental results showed that the loss of LPCS and one LPCI resulted in the highest PCT of 870 K of the single failure series tests, yet a core cooling capability by the ECCS was maintained. The REALP4/Mod 6 code was used to evaluate the predictive capability of the LOCA analysis code. The calculated results showed that the RELAP4/Mod 6 code was able to predict occurrences and sequence of major events anticipated to occur during a BWR LOCA correctly. However it was found that the code still needs to be improved in a CCFL model to better describe thermohydraulic behavior in the core. The analyses presented in this paper are valuable for evaluating the adequacy and improving the predictive capability of analytical models dev...