Measurement of the Internal Impedance of Traction Rails at Audiofrequency

2004 ◽  
Vol 53 (3) ◽  
pp. 792-797 ◽  
Author(s):  
A. Mariscotti ◽  
P. Pozzobon
Keyword(s):  
Internal Impedance

Internal impedance characterization for black box signal source

1997 ◽  
Author(s):  
K. C. Cheok ◽  
G. E. Smid ◽  
K. Kobayashi ◽  
F. Miesterfeld ◽  
R. Hormel
Keyword(s):  
Black Box ◽  
Signal Source ◽  
Internal Impedance ◽  
Impedance Characterization

Experimental Study on Performance of a Banded Structure Membrane Fuel Cell

2009 ◽  
Vol 6 (3) ◽  
Author(s):  
E. Ejiri ◽  
K. Yamada
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte Membrane ◽  
Specific Cell ◽  
Banded Structure ◽  
Term Operation ◽  
Electrolyte Membrane ◽  
Basic Performance ◽  
Internal Impedance ◽  
Cell Module

The basic performance of a banded structure membrane fuel cell module (rated power of 90W), which consisted of 15 polymer electrolyte membrane fuel cells laid out in a plane, was experimentally investigated. The results show that the module operated for a much longer time at an inclination angle, θ, of 90deg than at θ=0deg or 180deg, where it experienced a sudden power breakdown at the rated operating point. The output voltage and internal impedance of each cell in the module were specifically monitored over a long-term operation. Measurements were made of the temperature distribution of the entire module as well as of the oxygen concentration and relative humidity at a specific cell. Airflow near the cathode in a single cell was also visualized. It was concluded that the power breakdown was probably caused by flooding in the anode of one of the most downstream cells of the module.

Effect of expiratory loading on glottic dimensions in humans

1985 ◽  
Vol 58 (2) ◽  
pp. 605-611 ◽  
Author(s):  
T. P. Brancatisano ◽  
D. S. Dodd ◽  
P. W. Collett ◽  
L. A. Engel
Keyword(s):  
Inverse Relationship ◽  
Time Course ◽  
Normal Subjects ◽  
Positive End Expiratory Pressure ◽  
Expiratory Resistance ◽  
Mouth Pressure ◽  
Internal Impedance ◽  
Resistive Loads ◽  
Increased Activity ◽  
Medullary Neurons

We examined the effects of external mechanical loading on glottic dimensions in 13 normal subjects. When flow-resistive loads of 7, 27, and 48 cmH2O X l-1 X s, measured at 0.2 l/s, were applied during expiration, glottic width at the mid-tidal volume point in expiration (dge) was 2.3 +/- 12, 37.9 +/- 7.5, and 38.3 +/- 8.9% (means +/- SE) less than the control dge, respectively. Simultaneously, mouth pressure (Pm) increased by 2.5 +/- 4, 3.0 +/- 0.4, and 4.6 +/- 0.6 cmH2O, respectively. When subjects were switched from a resistance to a positive end-expiratory pressure at comparable values of Pm, both dge and expiratory flow returned to control values, whereas the level of hyperinflation remained constant. Glottic width during inspiration (unloaded) did not change on any of the resistive loads. There was a slight inverse relationship between the ratio of expiratory to inspiratory glottic width and the ratio of expiratory to inspiratory duration. Our results show noncompensatory glottic narrowing when subjects breathe against an expiratory resistance and suggest that the glottic dimensions are influenced by the time course of lung emptying during expiration. We speculate that the glottic constriction is related to the increased activity of expiratory medullary neurons during loaded expiration and, by increasing the internal impedance of the respiratory system, may have a stabilizing function.

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