Evaporative water loss in man in a gravity-free environment

1978 ◽  
Vol 45 (3) ◽  
pp. 430-436 ◽  
Author(s):  
C. S. Leach ◽  
J. I. Leonard ◽  
P. C. Rambaut ◽  
P. C. Johnson
Keyword(s):  
Water Balance ◽  
Water Loss ◽  
Convective Flow ◽  
Skin Surface ◽  
Water Losses ◽  
Evaporative Water ◽  
Average Decrease ◽  
Daily Exercise ◽  
The Mean ◽  
Free Environment

Daily evaporative water losses (EWL) during the three Skylab missions were measured indirectly using mass and water-balance techniques. The mean daily values of EWL for the nine crew members who averaged 1 h of daily exercise were: preflight 1,750 +/- 37 (SE) ml or 970 +/- 20 ml/m2 and inflight 1,560 +/- 26 ml or 860 +/- 14 ml/m2. Although it was expected the EWL would increase in the hypobaric environment of Skylab (one-third atmosphere). an average decrease from preflight sealevel conditions of 11% was measured. The results suggest that weightlessness decreased sweat losses during exercise and possibly reduced insensible skin losses as well. The weightlessness environment apparently promotes the formation of an observed sweat film on the skin surface during exercise by reducing convective flow and sweat drippage, resulting in high levels of skin wettedness that favor sweat suppression.

Microclimate preferences correlate with contrasted evaporative water loss in parapatric vipers at their contact zone

2014 ◽  
Vol 92 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Michaël Guillon ◽  
Gaëtan Guiller ◽  
Dale F. DeNardo ◽  
Olivier Lourdais
Keyword(s):  
Water Balance ◽  
Water Loss ◽  
Important Determinant ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Southern Limit ◽  
Vipera Berus ◽  
The Common ◽  
Vipera Aspis

Terrestrial ectotherms predominantly use behavioural means to thermoregulate and thereby optimize performances. However, thermoregulation can impart physiological challenges to other critical processes such as water balance by increasing evaporative water loss (EWL). Like thermoregulation, water balance is influenced by both external factors (e.g., microhabitat and environmental constraints) and endogenous traits (e.g., evaporative water loss rates, dehydration tolerance). Although thermoregulation and water balance are tightly linked, the role of water balance is often overlooked when evaluating species climatic adaptation and response to global warming. We studied two congeneric viperid species (the Aspic Viper, Vipera aspis (L., 1758), and the Common Viper, Vipera berus (L., 1758)) with contrasted climatic affinities (south European versus boreal, respectively). These parapatric species are syntopic in narrow contact zones where microhabitat partitioning has been reported. We compared total EWL and cutaneous evaporative water loss (CEWL) of the two species and monitored the thermal and hydric conditions of the microhabitats used in syntopic populations. We found that the boreal V. berus has greater EWL, both total and cutaneous. Accordingly, this species selected more humid microhabitats throughout the year. Humidity appears to be an important determinant of habitat selection, and therefore, V. berus is likely vulnerable to changing precipitation at the southern limit of its distribution.

Dew-point hygrometry system for measurement of evaporative water loss in infants

1997 ◽  
Vol 82 (3) ◽  
pp. 1008-1017 ◽  
Author(s):  
Ronald L. Ariagno ◽  
Steven F. Glotzbach ◽  
Roger B. Baldwin ◽  
David M. Rector ◽  
Susan M. Bowley ◽  
...  
Keyword(s):  
Water Loss ◽  
Water Vapor Pressure ◽  
Skin Surface ◽  
Term Infant ◽  
Evaporative Water Loss ◽  
Dew Point ◽  
Ambient Conditions ◽  
Evaporative Water ◽  
Clinical Investigations ◽  
Vapor Pressure Gradient

Ariagno, Ronald L., Steven F. Glotzbach, Roger B. Baldwin, David M. Rector, Susan M. Bowley, and Robert J. Moffat.Dew-point hygrometry system for measurement of evaporative water loss in infants. J. Appl. Physiol.82(3): 1008–1017, 1997.—Evaporation of water from the skin is an important mechanism in thermal homeostasis. Resistance hygrometry, in which the water vapor pressure gradient above the skin surface is calculated, has been the measurement method of choice in the majority of pediatric investigations. However, resistance hygrometry is influenced by changes in ambient conditions such as relative humidity, surface temperature, and convection currents. We have developed a ventilated capsule method that minimized these potential sources of measurement error and that allowed second-by-second, long-term, continuous measurements of evaporative water loss in sleeping infants. Air with a controlled reference humidity (dew-point temperature = 0°C) is delivered to a small, lightweight skin capsule and mixed with the vapor on the surface of the skin. The dew point of the resulting mixture is measured by using a chilled mirror dew-point hygrometer. The system indicates leaks, is mobile, and is accurate within 2%, as determined by gravimetric calibration. Examples from a recording of a 13-wk-old full-term infant obtained by using the system give evaporative water loss rates of ∼0.02 mgH2O ⋅ cm−2 ⋅ min−1for normothermic baseline conditions and values up to 0.4 mgH2O ⋅ cm−2 ⋅ min−1 when the subject was being warmed. The system is effective for clinical investigations that require dynamic measurements of water loss.

Metabolism, Water-Balance and Temperature Regulation in the Golden Bandicoot (Isoodon-Auratus)

1992 ◽  
Vol 40 (5) ◽  
pp. 523 ◽  
Author(s):  
PC Withers
Keyword(s):  
Body Temperature ◽  
Water Balance ◽  
Metabolic Rate ◽  
Basal Metabolic Rate ◽  
Temperature Regulation ◽  
Water Loss ◽  
Thermal Conductance ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Low Rate

The Barrow I. golden bandicoot (Isoodon auratus) is a small arid-adapted marsupial. It has a low and labile body temperature, a low basal metabolic rate, a low thermal conductance, and a low rate of evaporative water loss. Its metabolic, thermal and hygric physiology resembles that of another arid-adapted bandicoot, the bilby, and differs from temperate and tropical bandicoots.

Studies on anuran water balance—I. Dynamics of evaporative water loss by the coquí, eleutherodactylus portoricensis

1969 ◽  
Vol 28 (1) ◽  
pp. 245-269 ◽  
Author(s):  
Harold Heatwole ◽  
Frank Torres ◽  
Sheila Blasini De Austin ◽  
Audry Heatwole
Keyword(s):  
Water Balance ◽  
Water Loss ◽  
Evaporative Water Loss ◽  
Evaporative Water

House sparrows (Passer domesticus) increase protein catabolism in response to water restriction

2011 ◽  
Vol 300 (4) ◽  
pp. R925-R930 ◽  
Author(s):  
Alexander R. Gerson ◽  
Christopher G. Guglielmo
Keyword(s):  
Water Balance ◽  
Lean Mass ◽  
Water Loss ◽  
Passer Domesticus ◽  
Composition Analysis ◽  
Protein Catabolism ◽  
Water Restriction ◽  
House Sparrows ◽  
Evaporative Water ◽  
Body Protein

Birds primarily rely on fat for energy during fasting and to fuel energetically demanding activities. Proteins are catabolized supplemental to fat, the function of which in birds remains poorly understood. It has been proposed that birds may increase the catabolism of body protein under dehydrating conditions as a means to maintain water balance, because catabolism of wet protein yields more total metabolic and bound water (0.155·H2O−1·kJ−1) than wet lipids (0.029 g·H2O−1·kJ−1). On the other hand, protein sparing should be important to maintain function of muscles and organs. We used quantitative magnetic resonance body composition analysis and hygrometry to investigate the effect of water restriction on fat and lean mass catabolism during short-term fasting at rest and in response to a metabolic challenge (4-h shivering) in house sparrows ( Passer domesticus ). Water loss at rest and during shivering was compared with water gains from the catabolism of tissue. At rest, water-restricted birds had significantly greater lean mass loss, higher plasma uric acid concentration, and plasma osmolality than control birds. Endogenous water gains from lean mass catabolism offset losses over the resting period. Water restriction had no effect on lean mass catabolism during shivering, as water gains from fat oxidation appeared sufficient to maintain water balance. These data provide direct evidence supporting the hypothesis that water stress can increase protein catabolism at rest, possibly as a metabolic strategy to offset high rates of evaporative water loss.

scholarly journals WATER BALANCE AT PLANTS IN TECHNOLOGICAL SOLUTIONS ENGINEERING

2020 ◽  
Vol 1 (154) ◽  
pp. 148-153
Author(s):  
О. Galkina ◽  
М. Degtyar
Keyword(s):  
Water Management ◽  
Water Balance ◽  
Water Loss ◽  
Coke Plant ◽  
Water Circulation ◽  
Chemical Plants ◽  
Water Losses ◽  
Coke Plants ◽  
Phenolic Water ◽  
Phenolic Wastewater

In this paper questions and conditions of water management in the water-circulation systems taking into account water losses on the example of the coke-chemical plant are considered. The water balance of the primary gas refrigerators cycle at the Kharkiv coke plant has been calculated and compiled, taking into account the proposed technological solutions. As a result of the operation of the water-circulation systems, it was found that the water loss for evaporation at the Kharkiv Coke Plant is on average 2% in winter and 3% in summer. Water losses in the system are replenished with fresh technical water and purified phenolic wastewater. Technical appraisal of the work of heat-exchange equipment at coke plants is carried out consists of replacing part of fresh technical water with phenolic wastewater and minimizing wastewater discharges. The purpose of the project is to create conditions for the water re-use by coke-chemical plants and to predict its water balance depending on the technological decisions made. Thus, the purge of the system is 5.6 m3/hour, while the total irreparable water loss in the system is 9.4 m3/hour. In the article it is established that the application of the proposed technical solutions allows to reduce the amount of discharge of sewage into urban sewer network at 36 000 m3/year and consumption of fresh industrial water to 52 000 m3/year, and increase the service life of equipment from 6.5 to 8 years. These measures help to improve water and environmental situation, effective water management of the coke-plant, that is, to decrease the payment made for consumption of water resources and sewage plant. The presented water balance and calculations of losses of water in the reverse water supply system of the enterprise are executed prove positive effect from the proposed technology solutions. Keywords: phenolic water-circulation systems, coke plants, water management, water balance

Relationship between autonomic and behavioral thermoregulation in the golden hamster

1986 ◽  
Vol 251 (2) ◽  
pp. R320-R324 ◽  
Author(s):  
C. J. Gordon ◽  
K. S. Fehlner ◽  
M. D. Long
Keyword(s):  
Temperature Gradient ◽  
Metabolic Rate ◽  
Water Loss ◽  
Thermal Conductance ◽  
Evaporative Water Loss ◽  
Behavioral Thermoregulation ◽  
Evaporative Water ◽  
The Mean ◽  
Male Golden Hamsters ◽  
Colonic Temperature

Preferred ambient temperature (Ta) of male golden hamsters (Mesocricetus auratus) was measured repeatedly by placing the animals in a temperature gradient for 80 min. A total of 180 observations were made during the last 20 min of treatment in the gradient. The mean preferred Ta was 28.2 +/- 0.2 degrees C. In another experiment the same animals were placed in a temperature-controlled chamber for 80 min while metabolic rate, evaporative water loss, thermal conductance, and colonic temperature were measured at Ta's of 14-34 degrees C. The lower critical Ta, the Ta below which metabolic rate increased above the resting level, was 28 degrees C. This Ta corresponds closely to the mean preferred Ta of the hamster when placed in the temperature gradient. Evaporative water loss was minimal at Ta's of 14 and 16 degrees C and increased gradually with increasing Ta. Thermal conductance was minimal between Ta's of 14 and 28 degrees C and then increased sharply with increasing Ta. The data from the hamster are qualitatively similar to the mouse in that the preferred Ta corresponds with the lower critical Ta. It appears that, for these rodents, the control of preferred Ta is critically related to the animal's metabolic requirements.

scholarly journals Inundation and groundwater dynamics for quantification of evaporative water loss in tropical wetlands

2014 ◽  
Vol 18 (11) ◽  
pp. 4407-4422 ◽  
Author(s):  
J. Schwerdtfeger ◽  
M. S. Johnson ◽  
E. G. Couto ◽  
R. S. S. Amorim ◽  
L. Sanches ◽  
...  
Keyword(s):  
Water Balance ◽  
Water Loss ◽  
Regional Climate ◽  
Evaporative Water Loss ◽  
Water Bodies ◽  
Tropical Wetlands ◽  
Wet Season ◽  
Evaporative Water ◽  
Groundwater Levels ◽  
Second Stage

Abstract. Characterizing hydrological processes within tropical wetlands is challenging due to their remoteness, complexity and heterogeneity. In particular, estimates of evaporative water loss are inherently uncertain. In view of the large influence on the local and regional climate, the quantification of evaporation is essential for the determination of the water balance of permanent and intermittent water bodies. Data for tropical wetlands are scarce where their remoteness impedes direct evaporation measurements. Seasonal inundation dynamics affect evaporation processes in tropical wetlands, which can be analysed in two stages: the first stage during the wet season and the second stage during the dry season. As yet no adequate method exists for determining second-stage evaporation in a data-scarce environment that additionally allows for a transfer of simulated actual evaporation (AET) to other locations. Our study aimed at developing a process-based model to simulate first- and second-stage evaporation in tropical wetlands. We selected a set of empirical potential evaporation (PET) models of varying complexity, each based on different assumptions and available data sets, and evaluated the models with pan evaporation observations in the Pantanal of South America, one of the largest tropical wetlands in the world. We used high-resolution measurements of surface and groundwater levels at different locations to determine the water available for evaporation. AET was derived by constraining simulated PET based on available water. The model of best fit was applied to different types of water bodies with varying hydroperiods to capture first- and second-stage evaporation across a range of wetland types. With our new model we could quantify evaporative water loss in the dry and the wet season for different locations in the Pantanal. This new spatially explicit approach represents an improvement in our understanding of the role of evaporation in the water balance of the Pantanal. We recommend the application of this model in other remote tropical wetlands, since only a minimum of input data is necessary.

The Influence of Age, Diet and Lipid Content on Survival, Water Balance and Na+ and K+ Regulation in Dehydrating Cockroaches

1977 ◽  
Vol 71 (1) ◽  
pp. 81-93
Author(s):  
LOIS E. TUCKER
Keyword(s):  
Water Balance ◽  
Lipid Content ◽  
Water Loss ◽  
Periplaneta Americana ◽  
Fat Body ◽  
Late Instar ◽  
The Mean ◽  
Fat Bodies ◽  
Lipid Stores ◽  
Metabolic Water

In dehydrating conditions late instar nymphs lose weight more slowly and survive longer than adult Periplaneta americana. This appears to be due, at least in part, to the larger lipid stores which are found in the fat bodies of the nymphs. When the water loss from an animal is greater than the amount of metabolic water obtained from the catabolism of stored foods, water is removed from the haemolymph in order to maintain water balance in the tissues. Dehydration for 6 days causes the haemolymph volume to decrease markedly in most adults, but the haemolymph Na+ and K+ concentrations increase only slightly. During dehydration the mean Na+/K+ ratio of the fat body tissue increased in adults, except in those which had been fed on pure carbohydrate prior to dehydration. Although not always statistically significant on account of the large variances, the changes in mean Na+, K+ and in the Na+/K+ ratio suggest there is an increase in Na+ and decrease in K+ in the fat body of animals where the haemolymph volume is markedly reduced by dehydration.

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