Application of the aerodynamic energy concept to flutter suppression and gust alleviation by use of active controls

The effects of active controls on flutter suppression and gust alleviation of the Arava twin turboprop STOL transport and the Westwind twinjet business transport are investigated. The active control surfaces are introduced in pairs which include, in any chosen wing strip, a 20-percent chord leading-edge control and a 20-percent chord trailing-edge control. Each control surface is driven by a combined linear-rotational sensor system located on the activated strip. The control law is based on the concept of aerodynamic energy and utilizes previously optimized control law parameters based on two-dimensional aerodynamic theory. The best locations of the activated system along the span of the wing are determined for bending-moment alleviation, reduction in fuselage accelerations, and flutter suppression. The effectiveness of the activated system over a wide range of maximum control deflections is also determined. Two control laws are investigated. The first control law utilizes both rigid-body and elastic contributions of the motion. The second control law employs primarily the elastic contribution of the wing and leads to large increases in the activated control effectiveness as compared with the basic control law. The results indicate that flutter speed can be significantly increased (over 70 percent increase) and that the bending moment due to gust loading can be almost totally eliminated by a control system of about 10 to 20 percent span with reasonable control-surface rotations

Cryogenic-coolant He4-superconductor dynamic and static interactions

A composite superconducting material (NbTi-Cu) was evaluated with emphasis on post quench solid cooling interaction regimes. The quasi-steady runs confirm the existence of a thermodynamic limiting thickness for insulating coatings. Two distinctly different post quench regimes of coated composites are shown to relate to the limiting thickness. Only one regime,, from quench onset to the peak value, revealed favorable coolant states, in particular in He2. Transient recovery shows favorable recovery times from this post quench regime (not drastically different from bare conductors) for both single coated specimens and a coated conductor bundle

Measuring the Contributions of Motives and Perceived Barriers to Active Aging

General motivation to be active and general perceived barriers to activity may help to explain the overall activity patterns of older persons in the second half of the life course. We report on a project designed to develop and refine measures of motivation and perceived barriers that can be used to examine the relationships between activity motivation, activity barriers, and several forms of actual activities. Four specific activities were considered: working, volunteering, exercising, and taking classes. An opportunity sample of 192 middle-aged and older persons from eastern Massachusetts responded to a questionnaire concerned with motivation, perceived barriers, and activities. Reliable measures of both general and activity-specific motivation and perceived barriers to activity were developed. The measures were examined for construct validity purposes. This analysis demonstrates that general activity motivation and perceived barriers are helpful in understanding patterns of activity among older people

Elder Activities: Patterns, Motives, and Interpretation. Massachusetts Lifestyles Study III

We are engaged in a continuing effort to understand the scope of elder activity and the implications of activity for well-being. We are particularly interested in the forces that encourage or inhibit multiple forms of activity, the ways in which participation in some activities influences participation in other activities, and the cumulative implications of activities for well being. Our interest in multiple forms of activities sets us somewhat apart from Gerontologists who focus on single forms of activity such as volunteering, taking classes, caring for grandchildren, working, or exercising

Predicting the Counterproductive Employee in a Child-to-Adult Prospective Study

Abstract The present research tested the relations between a battery of background factors and counterproductive work behaviors in a 23-year longitudinal study of young adults (N = 930). Background information, such as diagnosed adolescent conduct disorder, criminal conviction records, intelligence, and personality traits, was assessed before participants entered the labor force. These background factors were combined with work conditions at age 26 to predict counterproductive work behaviors at age 26. The results showed that people diagnosed with childhood conduct disorder were more prone to commit counterproductive work behaviors in young adulthood and that these associations were partially mediated by personality traits measured at age 18. Contrary to expectations, criminal convictions that occurred prior to entering the workforce were unrelated to counterproductive work behaviors. Job conditions and personality traits had independent effects on counterproductive work behaviors, above and beyond background factors

A 6.3 T Bend Magnet for the Advanced Light Source

The Advanced Light Source (ALS) is a 1.5 to 1.9 GeV high-brightness electron storage ring operating at Lawrence Berkeley Laboratory (LBL) that provides synchrotron radiation for a large variety of users. It Is proposed to replace three of the thirty six 1.5T, one meter long bend magnets with very sbort high-field superconductlng (SC) dipoles. These magnets would provide bend-magnet synchrotron radiation to six bcamlines with a critical energy of at least 6 keV that is much better suited for protein crystallography and other small-sample x-ray diffraction and adsorption studies, than is currently available at the ALS. The magnet design is described, including coil, yoke, magnetic field analysis, and cyrostat. A prototype magnet is under construction at LBL