1. In post-tensioning, the region adjacent to the anchorage for the tendon which is subjected to secondary stresses as a result of the distribution of the pre-stressing force. 2. In pre-tensioning, the region in which transfer bond stresses are developed.

A frequency domain stability test for systems consisting of a linear component described by a transfer function preceded by a nonlinear component characterized by an input-output function), with a unity gain feedback loop surrounding the series connection.

A plot of the poles and zeros of a transfer function in the complex plane; used to study the stability of a system, its natural motion, its frequency response, and its transient response.

1.A flat plate against which something rests or is pressed. 2. The rubber-covered roller of a typewriter against which paper is pressed when struck by the typebars. 2. A flat surface for exchanging heat in a boiler or heat exchanger which may have extended heat transfer surfaces.

A solar heating or cooling system that operates by using gravity, heat flows, or evaporation rather than mechanical devices to collect and transfer energy.

A plot in the complex plane of the open-loop transfer function as the complex frequency is varied along the Nyquist contour; used to determine stability of a control system.

A dimensionless number used in the study of forced convection which gives a measure of the ratio of the total heat transfer to conductive heat transfer, and is equal to the heat-transfer coefficient times a characteristic length divided by the thermal conductivity. Symbolized NNu.

A feedback control in a system with more than one input and more than one output, in which feedback transfer functions are selected so that each input noncontact sensor See proximity sensor.