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16. Intelligent sensor-model automated control of PMR-15 autoclave processing

Author

Hart, S, Kranbuehl, D, Loos, A, Hinds, B, and Koury, J

Subjects
Mechanical Engineering
Abstract

An intelligent sensor model system has been built and used for automated control of the PMR-15 cure process in the autoclave. The system uses frequency-dependent FM sensing (FDEMS), the Loos processing model, and the Air Force QPAL intelligent software shell. The Loos model is used to predict and optimize the cure process including the time-temperature dependence of the extent of reaction, flow, and part consolidation. The FDEMS sensing system in turn monitors, in situ, the removal of solvent, changes in the viscosity, reaction advancement and cure completion in the mold continuously throughout the processing cycle. The sensor information is compared with the optimum processing conditions from the model. The QPAL composite cure control system allows comparison of the sensor monitoring with the model predictions to be broken down into a series of discrete steps and provides a language for making decisions on what to do next regarding time-temperature and pressure.

Published
1992

19. Control of tool wear during metal cutting using a computer and on line measurements.

Author

Hinds, B. K.

Subjects
METAL cutting, MECHANICAL wear, ADAPTIVE control systems, TOOLS, MACHINING, COMPUTERS, RESEARCH
Abstract

An adaptive control system is proposed in which a given amount of tool wear is allowed per operation. The objective of the control system is to machine a certain feed distance in the minimum time using no more than the wear allowed and working within the conventional adaptive control constraints. The average rate at which the operation progresses can thus be regulated by appropriately setting the wear target. The adaptive control system has been applied to the control of a lathe performing a simple bar turning operation. An on-line computer receives transducer responses, calculates and issues feed and speed corrections. The optimization policy requires the tool wear rate to be estimated while cutting and in this work the estimation was made from the cutting process variables including the tool-work thermocouple voltage. Workpiece disturbances in the form of hardness changes were introduced and the experimental responses of the control system to these disturbances are presented. The success of estimating wear rate on a sample of the controlled tests is also presented. [ABSTRACT FROM AUTHOR]

Published
1977
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24. Measurement and analysis of aerosol and black carbon in the southwestern united states and panama and their dependence on air mass origin

Author

Junker, C., Sheahan, J. N., Jennings, S. G., O'Brien, P., Hinds, B. D., Martinez-Twary, E., Hansen, A. D. A., White, C., Garvey, D. M., and Pinnick, R. G.

Subjects
long-range transport, size distributions, aerosol absorption, atmospheric aerosol, black carbon, time series analysis of aerosol data, attenuation cross-section, air mass trajectory, statistical analysis of aerosol data, optical-properties, aerosol mass, source regions, mace-head, thermal measurements, light-absorption, elemental carbon
Abstract

Total aerosol mass loading, aerosol absorption, and black carbon ( BC) content were determined from aerosol collected on 598 quartz fiber filters at a remote, semiarid site near Orogrande, New Mexico from December 1989 to October 1995. Aerosol mass was determined by weighing filters before and after exposure, and aerosol absorption was determined by measuring the visible light transmitted through loaded filter samples and converting these measurements to aerosol absorption. BC content was determined by measuring visible light transmitted through filter samples before and after firing and converting the absorption to BC mass, assuming a BC absorption cross section of 19 m(2)/g in the fiber filter medium. Two analyses were then performed on each of the logged variables: an autoregressive integrating moving average (ARIMA) analysis and a decomposition analysis using an autoregressive model to accommodate first-order autocorrelation. The two analyses reveal that BC mass has no statistically significant seasonal dependence at the 5% level of significance but only random fluctuations varying around an average annual value that has a long-term decreasing trend (from 0.16 to 0.11 mug/m(3) during 1990-1995). Aerosol absorption, which is dominated by BC, also displays random fluctuations about an average value, and decreases from 1.9 Mm(-1) to 1.3 Mm(-1) during the same period. Unlike BC, aerosol mass at the Orogrande site displays distinctly different character. The analyses reveal a pronounced seasonal dependence, but no long-term trend for aerosol mass. The seasonal indices resulting from the autoregression analysis have a minimum in January (-0.78) and maximum in June (+0.58). The geometric mean value over the 1990-1995 period for aerosol mass is 16.0 mug/m(3). Since BC aerosol at the Orogrande site is a product of long-range atmospheric transport, a back trajectory analysis of air masses was conducted. Back trajectory analyses indicate that air masses traversing high population centres on the west coast of the USA can lead to significant BC loading, while air masses originating from the southeast of the site tend to have less BC. Additional aerosol measurements are reported for a remote maritime site located on the Atlantic side of the former Panama Canal Zone for the 1976-1979 period, although these data have been analyzed with less statistical rigor. The average geometric mean value of aerosol mass loading for this site is 9.7 mug/m(3), with a significant decreasing trend of -19% per year. The mean value of aerosol absorption is 0.59 Mm(-1), with a decreasing trend of -15% per year.

Published
2004

25. Briefly

Author

Hinds, B., primary, Collier, R., additional, and Kondro, W., additional

Published
2010
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