The role of water for heat dissipation by a Jersey cow and a Corriedale ewe.

1954 ◽  
Vol 5 (3) ◽  
pp. 568 ◽  
Author(s):  
BJ Knapp ◽  
KW Robinson
Keyword(s):  
Human Skin ◽  
Water Loss ◽  
Heat Balance ◽  
Heat Dissipation ◽  
Unit Area ◽  
Heat Exposure ◽  
Total Water ◽  
Water Losses ◽  
Respiratory Mechanism

Experimental climatological work was carried out on a Jersey cow and a Corriedale ewe. These animals were exposed to a series of controlled environmental conditions in a psychrometric room for periods of 7 hr and their reactions observed. Both animals showed an increase in body temperature, respiratory rate and volume, and respiratory and transcutaneous water losses during heat exposure. Values and trends in these reactions were calculated for each exposure. Transcutaneous water loss by unit area of Jersey cow skin was of the same order as loss through human skin. Respiratory water loss formed only a small fraction — a fifth to a ninth — of the total water loss. In the sheep, however, respiratory water loss reached as much as one-third of the total water loss and the transcutaneous loss was one-third of that through human skin. It was concluded that the Jersey cow efficiently maintained a heat balance presumably by a good sweating mechanism. The Corriedale ewe, however, was a poorly sweating ruminant, relying mainly on the respiratory mechanism for approaching a heat balance.

scholarly journals Mechanisms and modifiers of reflex induced cutaneous vasodilation and vasoconstriction in humans

2010 ◽  
Vol 109 (4) ◽  
pp. 1221-1228 ◽  
Author(s):  
Nisha Charkoudian
Keyword(s):  
Blood Flow ◽  
Human Skin ◽  
Skin Blood Flow ◽  
Cold Exposure ◽  
Heat Dissipation ◽  
Sympathetic Innervation ◽  
Heat Exposure ◽  
Reproductive Hormones ◽  
Excessive Heat ◽  
Cutaneous Vasodilation

Human skin blood flow responses to body heating and cooling are essential to the normal processes of physiological thermoregulation. Large increases in skin blood flow provide the necessary augmentation of convective heat loss during environmental heat exposure and/or exercise, just as reflex cutaneous vasoconstriction is key to preventing excessive heat dissipation during cold exposure. In humans, reflex sympathetic innervation of the cutaneous circulation has two branches: a sympathetic noradrenergic vasoconstrictor system, and a non-noradrenergic active vasodilator system. Noradrenergic vasoconstrictor nerves are tonically active in normothermic environments and increase their activity during cold exposure, releasing both norepinephrine and cotransmitters (including neuropeptide Y) to decrease skin blood flow. The active vasodilator system in human skin does not exhibit resting tone and is only activated during increases in body temperature, such as those brought about by heat exposure or exercise. Active cutaneous vasodilation occurs via cholinergic nerve cotransmission and has been shown to include potential roles for nitric oxide, vasoactive intestinal peptide, prostaglandins, and substance P (and/or neurokinin-1 receptors). It has proven both interesting and challenging that no one substance has been identified as the sole mediator of active cutaneous vasodilation. The processes of reflex cutaneous vasodilation and vasoconstriction are both modified by acute factors, such as exercise and hydration, and more long-term factors, such as aging, reproductive hormones, and disease. This review will highlight some of the recent findings in these areas, as well as interesting areas of ongoing and future work.

scholarly journals The use of Frontier Analysis to assess the technical rigor of water loss performance indicators

2020 ◽  
Vol 3 (1) ◽  
pp. 102-117
Author(s):  
Alan S. Wyatt
Keyword(s):  
North America ◽  
Best Practices ◽  
Water Loss ◽  
Performance Indicators ◽  
Total Water ◽  
Water Losses ◽  
Frontier Analysis ◽  
Water Association ◽  
International Water ◽  
And Performance

Abstract The American Water Works Association (AWWA) has developed and disseminated advanced methods and performance indicators for assessing and reducing water losses in North America, based in large part on the methods and indicators developed by the International Water Association (IWA). However, many utilities and regulators still use the old, inaccurate, %NRW indicator. A robust, quantitative assessment of the technical rigor of water loss indicators was needed but could not be found in the literature. So, an innovative approach was developed, using Frontier Analysis which provided such a score of ‘technical rigor’. This paper presents this method, applied to three datasets from North America, assessing 15 candidate indicators for total water losses, apparent losses and real losses. The results provide quantitative ‘scores’ of the technical rigor of the candidate indicators. Indicators with relatively high scores align with indicators used in the IWA best practices. Other indicators, such as the %NRW indicator, were found to have low technical rigor. The conclusion of the paper summarizes the rigorous indicators, and suggests areas for further application of this method, and for further research.

Assessment of water loss in Harare, Zimbabwe

2016 ◽  
Vol 6 (4) ◽  
pp. 519-533 ◽  
Author(s):  
Michael Gregory Ndunguru ◽  
Zvikomborero Hoko
Keyword(s):  
Water Loss ◽  
Total Water ◽  
Water Leakage ◽  
Water Losses ◽  
Proactive Approach ◽  
System A ◽  
High Level ◽  
Water Loss Management ◽  
Real Losses

A major challenge facing water utilities is the high level of water losses, which affects the financial viability and adequacy of water in the system. A study was carried out from January to May 2012 to characterize water losses in selected areas of Harare, Zimbabwe. Assessment of the contribution of water leakage to total water loss was carried out through water audits in four selected suburbs. Minimum night flows were determined over a number of days, and the SANFLOW model was used to determine average real losses. The water loss expressed as a percentage of supply in the four suburbs ranged from 29 to 43%, and was above the level expected for well-performing utilities in developing countries of 23%. Leakage contributed most to the water loss (>70%). For the entire city, the study established that non-revenue water ranged from 43 to 74% over the period 2009–2011. The study concludes that water loss management in Harare is poor, and this is affecting the quality of service delivery. There is a need for Harare to take a more proactive approach to water loss management, including periodic water audits.

scholarly journals Evaluation of water loss in transit and surface runoff in a Brazilian semi-arid basin

2020 ◽  
Vol 15 (4) ◽  
pp. 1
Author(s):  
Cristian Epifanio Toledo ◽  
João Carlos Mohn Nogueira ◽  
Alexandre De Amorim Camargo
Keyword(s):  
Water Loss ◽  
Surface Runoff ◽  
High Efficiency ◽  
Heterogeneous Environments ◽  
Runoff Coefficient ◽  
Water Losses ◽  
Proposed Model ◽  
Reservoir Basin ◽  
In Transit ◽  
Semi Arid

The objective of this work was to propose and evaluate a model to estimate transit water losses and surface runoff in a Brazilian semi-arid basin, fundamental components in the hydrological studies of the region, such as in the verification of hydrological connectivity. The study area was the Orós Reservoir Basin, located in the state of Ceará. The modeling of transit water loss and surface runoff were developed based on the work of Araújo and Ribeiro (1996) and Peter et al. (2014). In the proposed model, the parameter of loss in transit (k) was estimated at 0.027 km-1 for a section of the river basin, and when simulated for other stretches it provided good flow results at the end of the stretch, obtaining an NSE of 82%. The value of the runoff coefficient was estimated at 3% and when evaluating a spatial variation of this coefficient in the basin, the values varied from 2% to 12%, and the use of specialized runoff coefficient (RC) values promoted a higher NSE in the discharge simulation in the basin. It is concluded that the proposed model to estimate transit water losses and surface runoff demonstrated a high efficiency in the simulation of hydrological processes. The basin of Orós reservoir presented a high variability of the coefficient of surface runoff, justifying the need for a greater spatiality of this coefficient in heterogeneous environments.

scholarly journals Role of heat balance on the microstructure evolution of cold spray coated AZ31B with AA7075

2021 ◽  
Author(s):  
Bahareh Marzbanrad ◽  
Mohammad Hadi Razmpoosh ◽  
Ehsan Toyserkani ◽  
Hamid Jahed
Keyword(s):  
Cold Spray ◽  
Microstructure Evolution ◽  
Heat Balance

scholarly journals Dissecting the Roles of Cuticular Wax in Plant Resistance to Shoot Dehydration and Low-Temperature Stress in Arabidopsis

2021 ◽  
Vol 22 (4) ◽  
pp. 1554
Author(s):  
Tawhidur Rahman ◽  
Mingxuan Shao ◽  
Shankar Pahari ◽  
Prakash Venglat ◽  
Raju Soolanayakanahally ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Low Temperature ◽  
Cold Acclimation ◽  
Water Loss ◽  
Cuticular Wax ◽  
Dehydration Stress ◽  
Wax Deposition ◽  
Cuticular Waxes ◽  
Gas Chromatography Mass Spectroscopy

Cuticular waxes are a mixture of hydrophobic very-long-chain fatty acids and their derivatives accumulated in the plant cuticle. Most studies define the role of cuticular wax largely based on reducing nonstomatal water loss. The present study investigated the role of cuticular wax in reducing both low-temperature and dehydration stress in plants using Arabidopsis thaliana mutants and transgenic genotypes altered in the formation of cuticular wax. cer3-6, a known Arabidopsis wax-deficient mutant (with distinct reduction in aldehydes, n-alkanes, secondary n-alcohols, and ketones compared to wild type (WT)), was most sensitive to water loss, while dewax, a known wax overproducer (greater alkanes and ketones compared to WT), was more resistant to dehydration compared to WT. Furthermore, cold-acclimated cer3-6 froze at warmer temperatures, while cold-acclimated dewax displayed freezing exotherms at colder temperatures compared to WT. Gas Chromatography-Mass Spectroscopy (GC-MS) analysis identified a characteristic decrease in the accumulation of certain waxes (e.g., alkanes, alcohols) in Arabidopsis cuticles under cold acclimation, which was additionally reduced in cer3-6. Conversely, the dewax mutant showed a greater ability to accumulate waxes under cold acclimation. Fourier Transform Infrared Spectroscopy (FTIR) also supported observations in cuticular wax deposition under cold acclimation. Our data indicate cuticular alkane waxes along with alcohols and fatty acids can facilitate avoidance of both ice formation and leaf water loss under dehydration stress and are promising genetic targets of interest.

scholarly journals The role of obesity in the relation between total water intake and urine osmolality in US adults, 2009–2012

2016 ◽  
Vol 104 (6) ◽  
pp. 1554-1561 ◽  
Author(s):  
Asher Y Rosinger ◽  
Hannah G Lawman ◽  
Lara J Akinbami ◽  
Cynthia L Ogden
Keyword(s):  
Water Intake ◽  
Urine Osmolality ◽  
Total Water ◽  
Total Water Intake

Thermoregulatory responses during competitive marathon running

1977 ◽  
Vol 42 (6) ◽  
pp. 909-914 ◽  
Author(s):  
M. B. Maron ◽  
J. A. Wagner ◽  
S. M. Horvath
Keyword(s):  
Skin Temperature ◽  
Marathon Running ◽  
Heat Illness ◽  
Mean Skin Temperature ◽  
Total Water ◽  
Water Losses ◽  
Thermoregulatory Responses ◽  
Marked Disparity ◽  
Skin Temperatures ◽  
Cool Conditions

To assess thermoregulatory responses occuring under actual marathon racing conditions, rectal (Tre) and five skin temperatures were measured in two runners approximately every 9 min of a competitive marathon run under cool conditions. Race times and total water losses were: runner 1 = 162.7 min, 3.02 kg; runner 2 = 164.6 min, 2.43 kg. Mean skin temperature was similar throughout the race in the two runners, although they exhibited a marked disparity in temperature at individual skin sites. Tre plateaued after 35--45 min (runner 1 = 40.0--40.1, runner 2 = 38.9--39.2 degrees C). While runner 2 maintained a relatively constant level for the remainder of the race, runner 1 exhibited a secondary increase in Tre. Between 113 and 119 min there was a precipitous rise in Tre from 40.9 to 41.9 degrees C. Partitional calorimetric calculations suggested that a decrease in sweating was responsible for this increment. However, runner 1's ability to maintain his high Tre and running pace for the remaining 44 min of the race and exhibit no signs of heat illness indicated thermoregulation was intact.

scholarly journals Effect of P2 receptor blockade on cutaneous vasodilation during rest and exercise in the heat in young men

2018 ◽  
Vol 43 (3) ◽  
pp. 312-315
Author(s):  
Naoto Fujii ◽  
Robert D. Meade ◽  
Jeffrey C. Louie ◽  
Pegah Akbari ◽  
Pierre Boulay ◽  
...  
Keyword(s):  
Heat Exposure ◽  
P2 Receptors ◽  
Moderate Intensity ◽  
Receptor Blockade ◽  
P2 Receptor ◽  
Moderate Intensity Exercise ◽  
Cutaneous Vasodilation ◽  
Oxide Synthase ◽  
Rest And Exercise

We assessed the role of purinergic P2 receptors in the regulation of cutaneous vasodilation in young adults at rest and during intermittent moderate-intensity exercise in the heat (35 °C). P2 receptor blockade augmented resting cutaneous vasodilation but had no influence during and following exercise. This increase was partly diminished by nitric oxide synthase inhibition. These results suggest a functional role of P2 receptors in the regulation of cutaneous vascular tone during ambient heat exposure at rest.

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