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Active structural control by fuzzy logic rules: An introduction

Description: A zeroth level introduction to fuzzy logic control applied to the active structural control to reduce the dynamic response of structures subjected to earthquake excitations is presented. It is hoped that this presentation will increase the attractiveness of the methodology to structural engineers in research as well as in practice. The basic concept of the fuzzy logic control are explained by examples and by diagrams with a minimum of mathematics. The effectiveness and simplicity of the fuzzy logic control is demonstrated by a numerical example in which the response of a single- degree-of-freedom system subjected to earthquake excitations is controlled by making use of the fuzzy logic controller. In the example, the fuzzy rules are first learned from the results obtained from linear control theory; then they are fine tuned to improve their performance. It is shown that the performance of fuzzy logic control surpasses that of the linear control theory. The paper shows that linear control theory provides experience for fuzzy logic control, and fuzzy logic control can provide better performance; therefore, two controllers complement each other.
Date: December 1996
Creator: Tang, Yu & Wu, Kung C.
Partner: UNT Libraries Government Documents Department

Wastes characterization using APSTNG technology

Description: The associated-particle sealed-tube neutron generator (APSTNG) interrogates the inspected object with 14-MeV neutrons from d-t reaction and detects the alpha-particle associated with each neutron inside a cone encompassing the region of interest. Gamma-ray spectra from resulting neutron reactions inside the inspected volume identify fissionable materials and many nuclides. Flight times from detection times of the gamma rays and alpha particles separate the prompt and delayed gamma-ray spectra and can yield coarse tomographic images from a single orientation. The high-energy neutrons and gamma rays penetrate large objects and dense materials. The gamma-ray detector and neutron generator can be on the same side of the interrogated objects, so walls and other confined areas can be inspected as well as sealed containers. No collimators or radiation shielding are needed. The neutron generator is simple and small. Commercial electronics are used. A complete system could be transported in a van. Laboratory and limited field tests indicate APSTNG could be useful in analyzing radioactive waste in drums, walls, soils, and processing systems, particularly for unknown or heterogeneous configurations that may attenuate radiation. Toxic chemicals could be identified in mixed waste, and the ability to detect pockets of water may address criticality concerns.
Date: March 1996
Creator: Rhodes, E. A. & Dickerman, C. E.
Partner: UNT Libraries Government Documents Department

Seismic active control by a heuristic-based algorithm

Description: A heuristic-based algorithm for seismic active control is generalized to permit consideration of the effects of control-structure interaction and actuator dynamics. Control force is computed at onetime step ahead before being applied to the structure. Therefore, the proposed control algorithm is free from the problem of time delay. A numerical example is presented to show the effectiveness of the proposed control algorithm. Also, two indices are introduced in the paper to assess the effectiveness and efficiency of control laws.
Date: May 1996
Creator: Tang, Yu
Partner: UNT Libraries Government Documents Department

Condensation of Metal Vapors: Mercury and the Kinetic Theory of Condensation

Description: Report issued by the Argonne National Laboratory discussing condensation theories of metal vapors. As stated in the introduction, "the objectives of this research then are critical analysis of condensation theories and data for metal vapors and experimental evaluation of the resistance to condensation for a representative metal such as mercury" (p. 18). This report includes tables, illustrations, and photographs.
Date: October 1964
Creator: Wilhelm, Donald J.
Partner: UNT Libraries Government Documents Department

Performance Characteristics of a Liquid Metal MHD Generator

Description: Report issued by the Argonne National Laboratory discussing the performance of magnetohydrodynamic generators. As stated in the abstract, "an experimental study was made of the performance characteristics of a liquid metal MHD generator utilizing single-phase sodium-potassium and two-phase sodium-potassium-nitrogen fluids. The purpose of this study was to compare the generator performance with theory for single-phase flow and to determine the effects of the introduction of the gaseous phase on the generator output and efficiency" (p. 9). This report includes tables, illustrations, and photographs.
Date: July 1964
Creator: Petrick, Michael & Lee, Kung-You
Partner: UNT Libraries Government Documents Department