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21.
Finite element piezothermoelasticity analysis and the active control of FGM plates with integrated piezoelectric sensors and actuators 总被引:3,自引:0,他引:3
An efficient finite element model is presented for the static and dynamic piezothermoelastic analysis and control of FGM
plates under temperature gradient environments using integrated piezoelectric sensor/actuator layers. The properties of an FGM plate are functionally graded in the thickness
direction according to a volume fraction power law distribution. A constant displacement-cum-velocity feedback control algorithm that couples the direct and inverse piezoelectric effects is applied to provide active feedback
control of the integrated FGM plate in a closed loop system. Numerical results for the static and dynamic control are presented
for the FGM plate, which consists of zirconia and aluminum. The effects of the constituent volume fractions and the influence
of feedback control gain on the static and dynamic responses of the FGM plates are examined.
Received: 13 March 2002 / Accepted: 5 March 2003
The work described in this paper was supported by a grant awarded by the Research Grants Council of the Hong Kong Special
Administrative Region, China (Project No. CityU 1024/01E). 相似文献
22.
We create a business as usual scenario for office equipment electricity use from industry forecasts of equipment sales, surveys of equipment densities by building type, measured data on wattage and usage by equipment type and projected lifetimes for equipment. We then calculate electricity used by building type and equipment type for Energy Star and advanced scenarios and explore the sensitivity of these results to variations in key input parameters. According to our analysis, the Energy Star programme will save the US almost US$1 billion annually starting in the year 2000, with minimal expenditure of public funds. 相似文献
23.
Joseph Judenberg 《Information Systems Management》1994,11(4):34-38
Appropriately structured arrangements for systems maintenance outsourcing can yield significant benefits to many organizations. This article reviews methods for assessing potential maintenance outsourcing suppliers, for defining service criteria, and for evaluating contract terms. 相似文献
24.
D Averill D Blockus B Brabson J Brom C Jung H Ogren DR Rust M Derrick P Kooijman JS Loos B Musgrave LE Price J Repond K Sugano B Cork C Akerlof J Chapman D Errede MT Ken DI Meyer H Neal D Nitz R Thun R Tschirhart S Abachi P Baringer BG Bylsma R DeBonte D Koltick EH Low RL McIlwain DH Miller CR Ng EI Shibata 《Canadian Metallurgical Quarterly》1989,39(1):123-137
25.
PHYSICS-BASED SIMULATION OF HIGH SPEED MACHINING 总被引:3,自引:0,他引:3
Eu-Gene Ng Tahany I. El-Wardany Mihaela Dumitrescu Mohamed A. Elbestawi 《Machining Science and Technology》2002,6(3):301-329
Computer simulation of high speed machining processes can provide a unique insight and reduce the number of design iterations required to advance and optimize the process. Predictive modeling of high speed machining of exotic materials has been hindered by the nonlinear behavior of this type of materials at extremely high strain, strain rate, and temperatures. This paper presents a physics-based modeling technology that includes the change in the material constitutive equation and the friction characterization at cutting speeds up to 400 m min-1. The dependence of the accuracy of the predicted parameters, such as the chip formation on cutting forces, chip/tool/workpiece interface temperature, stress and strain distributions are also discussed. The fundamentals of metal cutting were utilized to understand the effect of parameter changes in regimes that are outside current empirical knowledge databases. 相似文献
26.
Cynicism and Social Trust in the New Media Environment 总被引:1,自引:0,他引:1
Joseph N. Cappella 《The Journal of communication》2002,52(1):229-241
This article, with minor modifications, was the author's presidential speech to the International Communication Association conference, May 2001. It summarizes trends in social trust, trust in government, media, and other social institutions and evaluates the news and entertainment media's roles in these trends. Alternatives to causal accounts are proposed, including variations on genetic or "memetic" forms of explanation for media influences on macrosocial trends. 相似文献
27.
Joseph A Wehrmeyer Zhongxian ChengDavid M Mosbacher Robert W PitzRobin Osborne 《Combustion and Flame》2002,128(3):232-241
Several opposed jet flames, produced by a lean H2-air jet opposing a rich or lean C3H8-air jet, are investigated. Spontaneous Raman spectroscopy is used for major species concentration and temperature measurements along the opposed jet centerline. The hot products of the H2-air flame simulate the burnt gases of strong-burning near-stoichiometric reactants as they impinge upon a weak-burning lean or rich hydrocarbon-fueled reactant mix, a situation encountered in stratified charge operation of direct injection spark ignition engines. In addition the H2-air flame hot products facilitate experimental data interpretation through the absence of carbon-bearing species. Good agreement between numerical and experimental data are obtained for a rich (equivalence ratio, φ = 1.25) C3H8-air jet versus a lean (φ = 0.4) H2-air jet. Two lean C3H8-air jets (φ = 0.64 or 0.60), versus the φ = 0.4 H2-air jet, are also investigated. For both of these flames, the amount of CO2 production strongly depends upon φ, with the φ = 0.64 flame having a peak CO2 mole fraction an order of magnitude higher than for the φ = 0.60 flame, and the C3H8 flames burning either as a normal flame (high CO2) or as a “negative flame speed” flame producing little CO2 and then only through diffusion of C3H8 into the hot products jet. The numerically predicted and experimental CO2 profiles agree well for the positive flame speed flame, but the large discrepancy between predicted and measured peak CO2 in the negative flame speed flame suggests modeling improvements are needed for this type of flame. 相似文献
28.
A. T. Joseph 《Expert Systems》1991,8(2):119-127
ProKappa is an expert system tool kit developed by IntelliCorp in C using X-Windows for graphical interface. The SUN 3 or 4 version costs $9995/£7000 and $2595/£1800 for the interactive C environment.
This review covers ProKappa version 1.1, installed on a colour SUN SPARC Station 1 with the minimum recommended values of 12 Mb of memory and 30 Mb of swap space.
IntelliCorp can be contacted in the USA at 1975 El Camino Real West, Mountain View, CA 94040-2216 (+1 (415) 965-5500) and in the UK at 10 Jewry Street, Winchester, Hampshire SO23 8RZ (+44 (0)962 735348). 相似文献
This review covers ProKappa version 1.1, installed on a colour SUN SPARC Station 1 with the minimum recommended values of 12 Mb of memory and 30 Mb of swap space.
IntelliCorp can be contacted in the USA at 1975 El Camino Real West, Mountain View, CA 94040-2216 (+1 (415) 965-5500) and in the UK at 10 Jewry Street, Winchester, Hampshire SO23 8RZ (+44 (0)962 735348). 相似文献
29.
We consider the switchbox routing problem of two-terminal nets in the case when all thek nets lie on two adjacent sides of the rectangle. Our routing model is the standard two-layer model. We develop an optimal algorithm that routes all the nets whenever a routing exists. The routing obtained uses the fewest possible number of vias. A more general version of this problem (adjacent staircase) is also optimally solved.This research was supported in part by NSA Contract No. MDA-904-85H-0015, NSF Grant No. DCR-86-00378, and by NSF Engineering Research Centers Program NSFD CDR 88003012. 相似文献
30.
Atmospheric corrosion of reference metals in Antarctic sites 总被引:1,自引:0,他引:1
Manuel Morcillo Beln Chico Daniel de la Fuente Elisabete Almeida Günter Joseph Susana Rivero Blanca Rosales 《Cold Regions Science and Technology》2004,40(3):165-178
This paper presents the results obtained at three Antarctic test sites participating in the “Ibero-American Map of Atmospheric Corrosiveness” (MICAT), a project on atmospheric corrosion carried out during the period 1988–1994 at some 70 sites distributed across 12 countries of the Latin-American region, Spain and Portugal. The three Antarctic sites are located near the coastline.The singular climatic characteristics of Antarctic regions are related with the purity of the air, the absence of rainfall and the formation of ice on the metallic surface during an important part of the exposure time. However, electrochemical activity is possible below ice layers. This situation affects the structure and morphology of corrosion product films and the resulting corrosion rates of metallic surfaces. 相似文献