The transient respiratory responses of 10 normal male volunteers to step changes in work load from 0 to 300, 600, and 800 kpm/min were determined by breath-by-breath analysis for tidal volume, minute ventilation, respiratory frequency, end-tidal oxygen and carbon dioxide tensins, oxygen uptake, carbon dioxide elimination, respiratory exchange ratio, and heart rate. Ten experiments were averaged on a 5-s interval basis. Quantitative measures of the dynamics (delay times, half-times, times to peaks, times to plateaus, and plateau amplitudes) are presented. These parameters generally vary with work load and reflect the speed of response of various components of the system. Rapid ventilatory responses were seen at the initiation and termination of exercise; however, they required up to 32.5 s for full development. Repeated runs on three subjects at 600 kpm/min indicate that the experiments are grossly repeatable. The data, at the initiation of exercise, are consistent with the concept of cardiodynamic hyperpnea while the results are not as clear-cut at the termination of exercise.
Commercial PZT powders were processed with various levels of silver (I) oxide powder and the effects on sintering hehaviour, mechanical and electrical properties analysed. It was found that silver oxide additions significantly accelerate the sintering behaviour of soft doped PZT, but not hard doped PZT. The resulting metallic silver behaves as a heterovalent acceptor ion dopant, thereby depressing the soft piezoelectric properties such as coupling coefficients and dielectric constant in the poled direction. Above the saturation point of Ag in PZT, however, other effects begin to occur, resulting in a partial recovery of the dielectric constant. Silver additions were also found to increase the fracture strength of PZT, and values of over 170 MPa were measured. With sufficient additions the material formed after sintering was shown to be conductive.
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