Theory of psychrometry

Optical psychrometer for relative humidity measurement in non-conventional environments

“…A psychrometer is an instrument commonly used to measure relative humidity [6,7]. It consists of two similar thermometers, named dry-and wet-bulb thermometer: while the first presents its bulb freely exposed to the surrounding atmosphere, the second bulb is wrapped in an absorbent material such as muslin, which is immersed in water and works as a wick.…”

“…(2-3), the wavelength FBG signals were converted in temperature ones. The dry-bulb temperature T 1 , the stabilized wet-bulb temperature T 2 and their difference (T 1 -T 2 ) were used to evaluate the relative humidity values, by means of the psychometric table for standard atmospheric pressure [6]: it contains the relative humidity RH values corresponding to dew temperature T 2 and gradient (T 1 -T 2 ). A special algorithm was developed to signals acquisition and conditioning and temperature conversion ( fig.…”

“…Different devices for measurement were developed, mainly based on changes, caused by humidity variation, in mechanical properties, or in thermoelemental and psychometric properties, last in electric ones, in capacitive or resistive sensors [3][4]. A traditional family of humidity measurement devices are the dew-point sensors [5], particularly psychrometers [6,7]. Recent applications were developed using the properties of polymeric materials [8].…”

Methods of electron microscopy of biological and abiogenic structures in artificial gas atmospheres

“…NATURE OF THE ATMOSPHERE In all the biological works on atmospheric pressure electron microscopy, there is a common problem, humidity of samples (similar to how the quality of the surface depends on the wettability of a crystal and can be qualitatively determined by it in X ray structural and X ray diffraction analyses [70]). As is apparent from psychrometric principles [71], the rate of evapo ration of a liquid increases with the decrease in the pressure and relative humidity; hence, it is necessary to use a chamber that maintains a certain humidity, but this may conflict with the parameters of a gas col umn and/or chamber which are optimum for the reg istration. At the same time, the need for the psychro metric optimization for cells, tissues, or isolated frag ments can be considered to be proven (at least, long and thoroughly investigated for plants [72,73] and postulated on the basis of obvious considerations for the climatic stabilization during the cultivation of ani mal tissues in thermostatted incubators with a con trolled gas atmosphere [74][75][76]).…”