Parameterizations of aerodynamic resistance to heat and water transfer have a significant impact on the accuracy of models of land – atmosphere interactions and of estimated surface fluxes using spectro-radiometric data collected from aircrafts and satellites. We have used measurements from an eddy correlation system to derive the aerodynamic resistance to heat transfer over a bare soil surface...

This paper describes the use of a platinum resistance temperature detector to develop a calibration experiment and to introduce metrology principles. The Callender-Van Dusen equation is used to analyze the temperature-resistance characteristic of a detector. Linearity of this characteristic is explored using a MATLAB simulation. Resistance is measured at four different temperatures to estimate ...

Background: Routine lung function testing requires expensive equipment, or requires maximum expiratory effort. The airflow perturbation device (APD) is a light handheld device, allowing for serial measures of respiratory resistance noninvasively and effortlessly. Methods: In a convenience sample of 398 patients undergoing pulmonary function testing, we compared routine spirometric indices (forc...

Measurements of electrical resistance appear to be useful indicators of porosity and related water permeability in insect cuticle. To develop an adequate understanding of how such measurements relate to the physical and structural properties of the integument, we made detailed determinations of resistance and impedance values for pronotal cuticle in adult male Periplaneta americana. The most co...

OBJECTIVES To determine, in North American children, reference values for respiratory resistance measurements by the forced oscillation (Rfo) technique and to examine whether sitting height, as index of truncal length, is a better determinant of resistance, less influenced by race and gender, than standing height. DESIGN/SETTING A prospective cross-sectional study of healthy nonobese children...

Automatic balancing dc and ac resistance ratio bridges are the primary measurement devices used by National Measurement Institutes for the calibration of standard platinum resistance thermometers (SPRTs) on the International Temperature Scale of 1990 (ITS-90). Performance assessment of these resistance ratio bridges is critical to the determination of both the uncertainties of the measurements ...

Research reports on pulmonary function measurements often mention caffeine abstinence as a condition for testing subjects. Yet, the effects of caffeine on respiration are not well documented. This study was intended to investigate the physiological effects of caffeine on respiratory resistance measurements and the necessity of caffeine avoidance in such testing. Thirty-one subjects were adminis...

INTRODUCTION Pulmonary function tests allow an objective assessment of the degree of bronchial obstruction in collaborative subjects. The measurement of airway resistance using passive methods is very helpful in non-collaborative subjects. The objective of this study was to assess the applicability of measuring airway resistance by the interrupter technique (Rint) in pediatric subjects, determi...