Dynamic Testing Techniques Research Articles

Transient and Frequency Response of Air Quality Monitors

Results of dynamic or transient tests and steady state calibration of carbon monoxide and sulfur dioxide continuous air quality monitors are reported. Standard gases and permeation tubes were used to establish low level concentrations bpth for the steady-state calibration and the dynamic testing. The steady-state calibration was in excellent agreement with results obtained from grab samples of the calibration gas stream taken with standard gas bubblers and analyzed by the West and Gaeke procedure. Such tests have been carried out by other investigators with similar results. The important contribution of this paper lies in the application of dynamic testing techniques developed by the senior author and co-workers to determine the transient and frequency response characteristics of these air quality monitors.

遷音速における動的試験

Descriptions about two dynamic test techniques in a transonic wind tunnel are given together with the obtained results. The first is measurements of dynamic stability derivatives of cones and a delta wing employing the free oscillation method. By use of a refined model driving mechanism and a newly designed damping meter accurate values of dynamic stability derivatives were obtained with increased efficiency. The second is the measurement of surface pressure fluctuations of a two dimensional oscillating airfoil. Very small pressure transducers are installed in the model, which is oscillated in pitch by an electromagnetic shaker, and the corresponding pressure signals are analysed harmonically. From the fundamental component dynamically stable and unstable regions over the model were determined and the integrated stability derivatives were obtained. At the same time relation between the higher harmonics and the mechanism of an unsteady transonic flow was also studied.

Study of Carbon Black Structures in Rubber

Abstract The effect of carbon-black structures in rubber were studied using dynamic testing techniques. The aspects studied were the effects of the degree of vulcanization and the degree of dispersion on dynamic modulus and loss. Relationships were established between electrical conductivity and dynamic modulus, and between the maximum dynamic viscosity and the carbon-black modulus changes on oscillation. Finally, use was made of carbon-black/paraffin-oil mixtures as model materials in order to explain the effect of carbon-black structures on the modulus enhancement of carbon-black-loaded vulcanizates.