Determining the temperature and water vapour pressure gradient of the ambient air using a reversing two-sensor system. An application of energy balance measurements in a clearfelled and prescribed burnt area

1985 ◽  
Vol 35 (1-4) ◽  
pp. 255-265
Author(s):  
A RITARI ◽  
E STROMMER
Keyword(s):  
Energy Balance ◽  
Pressure Gradient ◽  
Water Vapour ◽  
Vapour Pressure ◽  
Ambient Air ◽  
Sensor System ◽  
Water Vapour Pressure ◽  
Burnt Area ◽  
Vapour Pressure Gradient

scholarly journals Can birds do it too? Evidence for convergence in evaporative water loss regulation for birds and mammals

2017 ◽  
Vol 284 (1867) ◽  
pp. 20171478 ◽  
Author(s):  
E. C. Eto ◽  
P. C. Withers ◽  
C. E. Cooper
Keyword(s):  
Water Vapour ◽  
Water Loss ◽  
Vapour Pressure ◽  
Vapour Pressure Deficit ◽  
Ambient Air ◽  
Evaporative Water Loss ◽  
Water Vapour Pressure ◽  
Evaporative Heat Loss ◽  
Evaporative Water ◽  
Water Vapour Pressure Deficit

Birds have many physiological characteristics that are convergent with mammals. In the light of recent evidence that mammals can maintain a constant insensible evaporative water loss (EWL) over a range of perturbing environmental conditions, we hypothesized that birds might also regulate insensible EWL, reflecting this convergence. We found that budgerigars ( Melopsittacus undulatus ) maintain EWL constant over a range of relative humidities at three ambient temperatures. EWL, expressed as a function of water vapour pressure deficit, differed from a physical model where the water vapour pressure deficit between the animal and the ambient air is the driver of evaporation, indicating physiological control of EWL. Regulating EWL avoids thermoregulatory impacts of varied evaporative heat loss; changes in relative humidity had no effect on body temperature, metabolic rate or thermal conductance. Our findings that a small bird can regulate EWL are evidence that this is a common feature of convergently endothermic birds and mammals, and may therefore be a fundamental characteristic of endothermy.

THE DIFFUSION OF WATER VAPOUR THROUGH VARIOUS BUILDING MATERIALS

1939 ◽  
Vol 17a (2) ◽  
pp. 15-32 ◽  
Author(s):  
J. D. Babbitt
Keyword(s):  
Diffusion Coefficient ◽  
Pressure Gradient ◽  
Water Vapour ◽  
Vapour Pressure ◽  
Building Materials ◽  
Building Construction ◽  
Materials Used ◽  
Vapour Pressure Gradient

A method of measuring the diffusion coefficient of water vapour through solids is outlined, and a table of the coefficients for various materials used in building construction is given. The method of employing these coefficients to calculate the vapour pressure gradient through a typical wall is shown, and this is applied to estimate the resistance to water vapour necessary to prevent condensation.

Water vapour pressure above saturated salt solutions at low temperatures

1999 ◽  
Vol 155 (2) ◽  
pp. 297-309 ◽  
Author(s):  
V Morillon ◽  
F Debeaufort ◽  
J Jose ◽  
J.F Tharrault ◽  
M Capelle ◽  
...  
Keyword(s):  
Water Vapour ◽  
Vapour Pressure ◽  
Low Temperatures ◽  
Water Vapour Pressure ◽  
Salt Solutions

The Study of Evaporation from Small Surfaces by the Direct Measurement of Water Vapour Pressure Gradients

1970 ◽  
Vol 53 (3) ◽  
pp. 753-762
Author(s):  
JOHN MACHIN
Keyword(s):  
Water Vapour ◽  
Direct Measurement ◽  
Vapour Pressure ◽  
Point Method ◽  
Dew Point ◽  
Water Vapour Pressure ◽  
Pressure Gradients ◽  
Pressure Measurements ◽  
Wind Speeds ◽  
Experimental Values

1. The construction, maintenance and calibration of a sensitive instrument capable of making numerous vapour-pressure measurements within humidity gradients by the dew-point method is described. 2. Coefficients of diffusion of water vapour in air, calculated from observed vapour-pressure gradients and measured rates of evaporation agree with theoretical and other experimental values in still air. 3. Apparent coefficients in wind speeds between 10 and 100 cm/s were significantly lower than those in still air. 4. This finding, together with the performance of the dew-point probe, is discussed in relation to its possible use in the study of evaporation from animals and plants.

scholarly journals Properties of hydrated TiO2 and SiO2 nanoclusters: dependence on size, temperature and water vapour pressure

Nanoscale ◽  
2018 ◽  
Vol 10 (45) ◽  
pp. 21518-21532 ◽  
Author(s):  
Andi Cuko ◽  
Antoni Macià Escatllar ◽  
Monica Calatayud ◽  
Stefan T. Bromley
Keyword(s):  
Water Vapour ◽  
Systematic Study ◽  
Vapour Pressure ◽  
Water Vapour Pressure ◽  
Nano Silica

The stabilities and properties of globally optimised (TiO2)M(H2O)N and (SiO2)M(H2O)N clusters with M = 4–16 and a range of N/M ratios are studied with respect temperature and water vapour pressure. Our systematic study provides a comparative reference for understanding hydration of nano-silica and nano-titania.

Study of the reaction CaSO4.½H2O (β-hemihydrate) = CaSO4 (β-soluble anhydrite)+½H2O in the temperature range 20–100° C

1965 ◽  
Vol 34 (268) ◽  
pp. 327-345 ◽  
Author(s):  
J. D. C. McConnell
Keyword(s):  
Water Vapour ◽  
Vapour Pressure ◽  
Physical Adsorption ◽  
Linear Increase ◽  
Water Vapour Pressure ◽  
Hydration Reaction ◽  
Temperature Range ◽  
Dehydration Reactions ◽  
Adsorption Of Water ◽  
Hydration And Dehydration

SummaryA thermogravimetric vacuum microbalance has been used to study the reaction between β-soluble anhydrite and water vapour in the temperature range 20–100° C. Equilibrium water-vapour pressures for the hydration reaction in this temperature range were determined directly and have been compared with available data obtained by Kelly, Southard, and Anderson (1941) in the temperature range 80–120° C. The kinetics of the hydration and dehydration reactions have also been studied in a series of isothermal experiments with varying water-vapour pressure. These experiments indicate that in a vapour-pressure range close to the equilibrium value very low rates for both hydration and dehydration are observed. Outside this range of vapour pressures both hydration and dehydration rates increase suddenly and show an approximately linear increase with imposed water-vapour pressure.At low temperatures (25° C) the dehydration reaction has an associated activation energy of approximately 10 kcal mole−1. In the same temperature range additional, physical adsorption of water vapour by the specimen was noted.

Techniques and Applications for Imaging Biological Samples in a Low Vacuum Environmental Scanning Electron Microscope

2001 ◽  
Vol 7 (S2) ◽  
pp. 782-783
Author(s):  
C. J. Gilpin.
Keyword(s):  
Water Vapour ◽  
Biological Samples ◽  
Vapour Pressure ◽  
Water Vapour Pressure ◽  
Environmental Scanning ◽  
Sample Collection ◽  
Electron Microscopes ◽  
A Site ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

Of all the commercially available scanning electron microscopes which operate at “low vacuum” the ESEM is the most suitable for examining biological samples. in order to maintain samples with liquid water present the specimen chamber must be capable of operating at a pressure of at least 4.6 Torr (611 pascals) of water vapour pressure (the vapour pressure of water at 0°C). Use of lower pressures or a chamber gas other than water vapour will result in evaporation of water from the sample at a rate dependant on the partial pressure difference between the sample and its surrounding environment. Tables of relative humidity as a function of water vapour pressure and temperature are readily available to calculate desired settings for the microscope.One of the difficulties associated with examining fresh biological material is the need to have the microscope and sample available in the same location at the same time.If sample collection occurs at a site remote from the microscope inevitable necrotic changes will occur before examination can be carried out.

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