Transient Analysis of Microorganism Temperature and Evaporative Losses in an Algae Biofilm Photobioreactor

2011 ◽  
Author(s):  
Thomas E. Murphy ◽  
Halil Berberoglu
Keyword(s):  
Ambient Temperature ◽  
Water Loss ◽  
High Surface ◽  
Volume Ratio ◽  
Ambient Air ◽  
Evaporative Water Loss ◽  
Environmental Data ◽  
Biofuel Production ◽  
Solar Irradiation ◽  
Evaporative Water

This study describes the thermal modeling of a novel algal biofilm photobioreactor aimed at cultivating algae for biofuel production. The thermal model is developed to assess the photo-bioreactor’s thermal profile and evaporative water loss rate for a range of environmental parameters, including relative humidity, ambient air temperature, solar irradiation, and wind speed. First, a 24 hour simulation of the system has been performed using environmental data for Memphis, TN, USA on a typical spring day to assess the diurnal variations in system performance. Then, a sensitivity analysis is performed to assess the effect of each environmental parameter on the temperature and evaporative losses of the photobioreactor. It is observed that because of the high surface area-to-volume ratio of the system, the temperature of the system exceeds that of the maximum ambient temperature during daylight hours by approximately 0.5 °C and is lower than the minimum ambient temperature at night by approximately 1.4 °C because of evaporative and radiative cooling. Furthermore, without active cooling, the characteristic evaporative water loss from the system is approximately 4.8 L/m2-day.

Temperature Fluctuation and Evaporative Loss Rate in an Algae Biofilm Photobioreactor

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Thomas E. Murphy ◽  
Halil Berberoğlu
Keyword(s):  
Water Loss ◽  
Loss Rate ◽  
Environmental Parameters ◽  
Ambient Air ◽  
Evaporative Water Loss ◽  
Environmental Data ◽  
Biofuel Production ◽  
Solar Irradiation ◽  
Evaporative Water ◽  
Evaporative Loss

This study describes the thermal modeling of a novel algal biofilm photobioreactor aimed at cultivating algae for biofuel production. The thermal model is developed to assess the photobioreactor’s thermal profile and evaporative water loss rate for a range of environmental parameters, including ambient air temperature, solar irradiation, relative humidity, and wind speed. First, a week-long simulation of the system has been performed using environmental data for Memphis, TN, on a typical week during the spring, summer, fall, and winter. Then, a sensitivity analysis was performed to assess the effect of each weather parameter on the temperature and evaporative loss rate of the photobioreactor. The range of the daily algae temperature variation was observed to be 12.2  °C, 13.2 °C, 11.7 °C, and 8.2 °C in the spring, summer, fall, and winter, respectively. Furthermore, without active cooling, the characteristic evaporative water loss from the system is approximately 6.0 L/m2 day, 7.3 L/m2 day, 3.4 L/m2 day, and 1.0 L/m2 day in the spring, summer, fall, and winter, respectively.

Water loss and nitrogen excretion in sharp-nosed reed frogs (Hyperolius nasutus: anura, Hyperoliidae)

1982 ◽  
Vol 97 (1) ◽  
pp. 335-343
Author(s):  
P. C. Withers ◽  
S. S. Hillman ◽  
R. C. Drewes ◽  
O. M. Sokol
Keyword(s):  
Surface Area ◽  
Water Loss ◽  
High Surface ◽  
Waste Product ◽  
Volume Ratio ◽  
Evaporative Water Loss ◽  
Nitrogen Excretion ◽  
Mucous Gland ◽  
Specific Rate ◽  
Evaporative Water

Sharp-nosed African reed frogs, Hyperolius nasutus Gunther, are small (0.4 g) hyperoliids which have minimal rates of evaporative water loss (4.5 mg g-1 h-1; 0.3 mg cm-2 h-1) that are only 1/10 to 1/20 that of a typical frog, Hylaregilla, of comparable size (171 mg g-1 h-1, 4.8 mg cm-2 h-1). The surface-area-specific resistance to water flux of H. nasutus dorsal skin (96–257 sec cm-1) is similar to that of other ‘waterproof’ frogs (300–400), of cocooned frogs (40–500), and of desert reptiles (200–1400). However, H. nasutus can greatly increase the rate of evaporative water loss during radiative heat stress by mucous gland discharge, and by exposing the ventral skin. Urea is the principal nitrogenous waste product of H. nasutus and uric acid comprises less than 1% of the total nitrogen excretion for both H. nasutus and H. regilla. Other ‘waterproof’ frogs, in contrast, are uricotelic. Lethal dehydration requires less than two weeks in H. nasutus, despite its low surface-area-specific rate of water loss, because of its small size and concomitantly high surface-to-volume ratio. The rate of urea accumulation during dehydration was 23 mM g-1 day-1, which is sufficiently low that urea accumulation would not be lethal before the frog had succumbed to dehydrational death. Consequently, there appears to be little or no selective advantage for uricotely in small ‘waterproof’ frogs, such as H. nasutus.

Evaporative water loss in domestic fowls and its partition in relation to ambient temperature

1976 ◽  
Vol 87 (3) ◽  
pp. 527-532 ◽  
Author(s):  
S. A. Richards
Keyword(s):  
Ambient Temperature ◽  
Water Loss ◽  
Absolute Humidity ◽  
Evaporative Water Loss ◽  
Linear Functions ◽  
Whole Body ◽  
Water Vapour Pressure ◽  
Evaporative Water ◽  
Open Flow ◽  
Low Levels

SummaryThe rate of evaporative water loss has been studied in domestic fowls in the ambient temperature range from 0 to 40°C.Results for whole-body evaporation were similar when obtained by the open-flow and direct-weighing methods. At low levels of absolute humidity the rate increased by 0·03 mg/(g.h.°C) from 0 to 22 °C and by 0·17 mg/(g.h.°C) from 23 to 40 °C. Wholebody evaporation decreased with rising ambient water vapour pressure by 0·7 mg/(g.h.kPa).Cutaneous water loss was greater than respiratory water loss below 21 °C; it accounted for 78% of whole-body evaporation at 0 °C, falling to 25% at 40 °C.The rates of respiratory and whole-body evaporation could both be expressed as linear functions of respiratory frequency.

Physiological responses of a rodent to heliox reveal constancy of evaporative water loss under perturbing environmental conditions

2014 ◽  
Vol 307 (8) ◽  
pp. R1042-R1048 ◽  
Author(s):  
Christine Elizabeth Cooper ◽  
Philip Carew Withers
Keyword(s):  
Water Vapor ◽  
Metabolic Rate ◽  
Environmental Conditions ◽  
Water Loss ◽  
Physiological Responses ◽  
Ambient Air ◽  
Minute Volume ◽  
Evaporative Water Loss ◽  
Evidence Based ◽  
Evaporative Water

Total evaporative water loss of endotherms is assumed to be determined essentially by biophysics, at least at temperatures below thermoneutrality, with evaporative water loss determined by the water vapor deficit between the animal and the ambient air. We present here evidence, based on the first measurements of evaporative water loss for a small mammal in heliox, that mammals may have a previously unappreciated ability to maintain acute constancy of total evaporative water loss under perturbing environmental conditions. Thermoregulatory responses of ash-grey mice ( Pseudomys albocinereus) to heliox were as expected, with changes in metabolic rate, conductance, and respiratory ventilation consistent with maintaining constancy of body temperature under conditions of enhanced heat loss. However, evaporative water loss did not increase in heliox. This is despite our confirmation of the physical effect that heliox augments evaporation from nonliving surfaces, which should increase cutaneous water loss, and increases minute volume of live ash-grey mice in heliox to accommodate their elevated metabolic rate, which should increase respiratory water loss. Therefore, mice had not only a thermoregulatory but also a hygroregulatory response to heliox. We interpret these results as evidence that ash-grey mice can acutely control their evaporative water loss under perturbing environmental conditions and suggest that hygroregulation at and below thermoneutrality is an important aspect of the physiology of at least some small mammals.

Thermoregulation, Oxygen-Consumption and Water Turnover in Stubble Quail, Coturnix-Pectoralis, and King Quail, Coturnix-Chinensis

1986 ◽  
Vol 34 (1) ◽  
pp. 25 ◽  
Author(s):  
JR Roberts ◽  
RV Baudinette
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Ambient Temperature ◽  
Water Loss ◽  
Evaporative Water Loss ◽  
Arid Areas ◽  
Water Turnover ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Regulate Body Temperature

Stubble quail occur in more arid areas of Australia than king quail; however, the rates of metabolism and the ability to regulate body temperature in response to varying ambient temperature are similar in both birds, and resemble those of other quail species. At high ambient temperatures, rates of heat loss mediated by evaporative water loss are lower than those previously reported for more xerophilic species. Overall rates of water turnover and evaporative water loss at lower ambient temperatures are at the lower end of the range predicted for birds.

Water collection by the body in a viperid snake, Bothrops moojeni

2000 ◽  
Vol 21 (4) ◽  
pp. 485-492 ◽  
Author(s):  
Augusto Abe ◽  
Denis Andrade
Keyword(s):  
Body Surface ◽  
Water Loss ◽  
Functional Significance ◽  
Close Contact ◽  
Volume Ratio ◽  
The Body ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Water Collection ◽  
Bothrops Moojeni

AbstractWe describe a previously unreported behavior for water collection in juveniles of a neotropical viperid snake, Bothrops moojeni. When sprayed over, this snake displays a stereotyped coiling, bringing its body loops in close contact with each other, so that water is retained between the loops and over the body surface. This water is continuously ingested during and after its collection. The functional significance of the water collecting behavior is suggested to be related with the acquisition of water from short rainfalls, and with the special climatic and geologic conditions of B. moojeni habitat. Rates of evaporative water loss did not differ between juvenile and adult snakes, but since juveniles have a greater surface-to-volume ratio, they were significantly more sensitive to desiccation than the adults.

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.

scholarly journals Two lines of evidence for physiological control of insensible evaporative water loss by a tiny marsupial

2020 ◽  
Vol 223 (23) ◽  
pp. jeb234450
Author(s):  
Christine Elizabeth Cooper ◽  
Philip Carew Withers
Keyword(s):  
Water Loss ◽  
Vapour Pressure Deficit ◽  
Ambient Air ◽  
Physical Effect ◽  
Evaporative Water Loss ◽  
Physiological Control ◽  
Evaporative Water ◽  
Advantages And Disadvantages ◽  
Environmental Selection ◽  
Lines Of Evidence

ABSTRACTWe present two independent lines of evidence that a tiny dasyurid marsupial, the ningaui (Ningaui spp.), has acute physiological control of its insensible evaporative water loss below and within thermoneutrality. Perturbation of the driving force for evaporation by varying relative humidity, and therefore the water vapour pressure deficit between the animal and the ambient air, does not have the expected physical effect on evaporative water loss. Exposure to a helox atmosphere also does not have the expected physical effect of increasing evaporative water loss for live ningauis (despite it having the expected effect of increasing heat loss for live ningauis), but increases evaporative water loss for dead ningauis. We discuss the relative advantages and disadvantages of both experimental approaches for demonstrating physiological control of insensible evaporative water loss. An appreciation of physiological control is important because insensible evaporative water loss contributes to both water and heat balance, is clearly under environmental selection pressure, and potentially impacts the distribution of endotherms and their response to environmental change.

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