Temperature changes of the hypothalamus and body core in ducks feeding in cold water

1979 ◽  
Vol 378 (3) ◽  
pp. 227-230 ◽  
Author(s):  
I. Schmidt ◽  
E. Simon
Keyword(s):  
Cold Water ◽  
Temperature Changes ◽  
Body Core

Skinfolds and resting heat loss in cold air and water: temperature equivalence

1975 ◽  
Vol 39 (1) ◽  
pp. 93-102 ◽  
Author(s):  
R. M. Smith ◽  
J. M. Hanna
Keyword(s):  
Heat Transfer ◽  
Water Temperature ◽  
Heat Loss ◽  
Air Temperature ◽  
Indirect Calorimetry ◽  
Cold Water ◽  
Heat Conductance ◽  
Air Temperatures ◽  
Body Core ◽  
Male Subjects

Fourteen male subjects with unweighted mean skinfolds (MSF) of 10.23 mm underwent several 3-h exposures to cold water and air of similar velocities in order to compare by indirect calorimetry the rate of heat loss in water and air. Measurements of heat loss (excluding the head) at each air temperature (Ta = 25, 20, 10 degrees C) and water temperature (Tw = 29–33 degrees C) were used in a linear approximation of overall heat transfer from body core (Tre) to air or water. We found the lower critical air and water temperatures to fall as a negative linear function of MSF. The slope of these lines was not significantly different in air and water with a mean of minus 0.237 degrees C/mm MSF. Overall heat conductance was 3.34 times greater in water. However, this value was not fixed but varied as an inverse curvilinear function of MSF. Thus, equivalent water-air temperatures also varied as a function of MSF. Between limits of 100–250% of resting heat loss the followingrelationships between MSF and equivalent water-air temperatures were found (see article).

Thermal Protection System for Underwater Use in Cold and Hot Water

2010 ◽  
Vol 2 (1) ◽  
Author(s):  
Joseph C. Mollendorf ◽  
David R. Pendergast
Keyword(s):  
Thermal Protection ◽  
Cold Water ◽  
Electrical Power ◽  
Thermal Protection System ◽  
Hot Water ◽  
Protection System ◽  
Working Fluid ◽  
Physiological Data ◽  
Wide Range ◽  
Body Core

Underwater workers, sport and military divers, are exposed to thermal stress since most of the waters of the world are below or above what is thermally neutral. Although divers wear insulation suits for passive thermal protection they are inadequate. Active heating is currently accomplished by resistive heating and open-flow tubes delivering hot water; however, these methods are problematic. The challenge of this project was to design, build and test an active diver thermal protection system (DTPS) to be used with wet suit insulation that is effective, user-friendly, reliable, and that could be used by a free-swimming diver. The DTPS has a minimum number of moving parts, is low maintenance, has no unsafe or toxic working fluid and uses no consumables except a safe, high density, modular electrical power source. A portable and swimmable, self-contained, electrically powered unit (DTPS) has been designed, built, and tested that produces and circulates thermally conditioned water in a closed-loop through a zoned tube suit worn by a diver under a wetsuit to maintain skin and body core temperatures within prescribed safe limits. The system has been validated by using physiological data taken on human subjects over a wide range of ambient water temperatures. Corresponding enthalpy and electrical power measurements were used as the basis of a thermodynamic analysis. The DTPS maintained skin and body core temperatures within safe and functional ranges by providing up to about 200 W of heating in cold water and up to about 330 W of cooling in hot water. The corresponding electrical power consumption was up to about 300 W in cold water and up to about 1500 W in hot water. The results of a complete audit of the power use and heat transfer are presented along with the efficiency of the thermoelectric heating/cooling modules and the duty cycle of the system for a range of water immersion temperatures from 10°C to 39°C. The DTPS proved to be an effective and reliable apparatus for diver thermal protection in water temperatures from 10°C to 39°C, which covers most of the range of the earth’s waters. The data presented here can be used to modify the design of the DTPS to meet specific needs of the diving community.

scholarly journals Canine hyperthermia with cerebral protection

1976 ◽  
Vol 40 (4) ◽  
pp. 543-548 ◽  
Author(s):  
R. W. Carithers ◽  
R. C. Seagrave
Keyword(s):  
Core Temperature ◽  
Cold Water ◽  
Brain Temperature ◽  
Body Core Temperature ◽  
Whole Body ◽  
Similar Time ◽  
Data Points ◽  
Body Core ◽  
Heat Transfer System ◽  
The Brain

Extreme whole-body hyperthermia was achieved without lasting side effects in canines by elevating body core temperature to 42 degrees C, using a warm water bath. Cold water irrigation of the nasal alar fold permitted an additional core temperature elevation of 0.5–1.0 degrees C above brain temperature for periods up to 1.5 h. The brain-core temperature differential was maintained by a physiological arteriovenous heat exchanger located at the base of the brain. The maximum tolerable core temperature for the 21 nonirrigated dogs was 42 degrees C for 60–90 min, whereas that for the 28 irrigated dogs was 42.5–43 degrees C for similar time intervals. A mathematical model of the total heat transfer system described the observed dynamic temperature responses. It was the solution of a differential equation which fit the normalized experimental data points and predicted reasonable values for known and unknown experimental parameters.

scholarly journals Microgel that swims to the beat of light

2021 ◽  
Vol 44 (6) ◽  
Author(s):  
Ahmed Mourran ◽  
Oliver Jung ◽  
Rostislav Vinokur ◽  
Martin Möller
Keyword(s):  
Body Shape ◽  
Cold Water ◽  
Pulse Sequence ◽  
Temperature Cycling ◽  
Infrared Light ◽  
Coupled Modes ◽  
Temperature Changes ◽  
Rectangular Container ◽  
Forward Locomotion ◽  
Dispersed Gold

Abstract Complementary to the quickly advancing understanding of the swimming of microorganisms, we demonstrate rather simple design principles for systems that can mimic swimming by body shape deformation. For this purpose, we developed a microswimmer that could be actuated and controlled by fast temperature changes through pulsed infrared light irradiation. The construction of the microswimmer has the following features: (i) it is a bilayer ribbon with a length of 80 or 120 $$\upmu $$ μ m, consisting of a thermo-responsive hydrogel of poly-N-isopropylamide coated with a 2-nm layer of gold and equipped with homogeneously dispersed gold nanorods; (ii) the width of the ribbon is linearly tapered with a wider end of 5 $$\upmu $$ μ m and a tip of 0.5 $$\upmu $$ μ m; (iii) a thickness of only 1 and 2 $$\upmu $$ μ m that ensures a maximum variation of the cross section of the ribbon along its length from square to rectangular. These wedge-shaped ribbons form conical helices when the hydrogel is swollen in cold water and extend to a filament-like object when the temperature is raised above the volume phase transition of the hydrogel at $$32\,^{\circ } \hbox {C}$$ 32 ∘ C . The two ends of these ribbons undergo different but coupled modes of motion upon fast temperature cycling through plasmonic heating of the gel-objects from inside. Proper choice of the IR-light pulse sequence caused the ribbons to move at a rate of 6 body length/s (500 $$\upmu $$ μ m/s) with the wider end ahead. Within the confinement of rectangular container of 30 $$\upmu $$ μ m height and 300 $$\upmu $$ μ m width, the different modes can be actuated in a way that the movement is directed by the energy input between spinning on the spot and fast forward locomotion. Graphic abstract

scholarly journals Dynamic motion monitoring of a 3.6 km long steel rod in a borehole during cold-water injection with distributed fiber-optic sensing

2021 ◽  
Author(s):  
Martin P. Lipus ◽  
Felix Schölderle ◽  
Thomas Reinsch ◽  
Christopher Wollin ◽  
Charlotte M. Krawczyk ◽  
...  
Keyword(s):  
Thermal Stresses ◽  
Fiber Optic ◽  
Cold Water ◽  
Water Injection ◽  
Strain Sensing ◽  
Distributed Temperature Sensing ◽  
Stick Slip ◽  
Temperature Changes ◽  
Flow Monitoring ◽  
Sucker Rod

Abstract. Fiber-optic distributed acoustic sensing (DAS) data finds many applications in wellbore monitoring such as e.g. flow monitoring, formation evaluation, and well integrity studies. For horizontal or highly deviated wells, wellbore fiber-optic installations can be conducted by mounting the sensing cable to a rigid structure (casing/tubing) which allows for a controlled landing of the cable. We analyze a cold-water injection phase in a geothermal well with a 3.6 km long fiber-optic installation mounted to a ¾” sucker-rod by using both DAS and distributed temperature sensing (DTS) data. During cold-water injection, we observe distinct vibrational events (shock waves) which originate in the reservoir interval and migrate up- and downwards. We use temperature differences from the DTS data to determine the theoretical thermal contraction and integrated DAS data to estimate the actual deformation of the rod construction. The results suggest that the rod experiences thermal stresses along the installation length – partly in the compressional and partly in the extensional regime. We find strong evidence that the observed vibrational events originate from the release of the thermal stresses when the friction of the rod against the borehole wall is overcome. Within this study, we show the influence of temperature changes on the acquisition of distributed acoustic/strain sensing data along a fiber-optic cable suspended along a rigid but freely hanging rod. We show that observed vibrational events do not necessarily originate from induced seismicity in the reservoir, but instead, can originate from stick-slip behavior of the rod construction that holds the measurement equipment.

scholarly journals Energetically Defining the Thermal Limits of the Snow Crab

1989 ◽  
Vol 145 (1) ◽  
pp. 371-393 ◽  
Author(s):  
TIMOTHY P. FOYLE ◽  
RONALD K. O'DOR ◽  
ROBERT W. ELNER
Keyword(s):  
Food Consumption ◽  
Cold Water ◽  
Caloric Intake ◽  
Oxygen Demand ◽  
Energy Budgets ◽  
Snow Crab ◽  
Temperature Sensitive ◽  
Growth Equation ◽  
Temperature Changes ◽  
Lactate Levels

The snow crab, Chionoecetes opilio, is a cold-water species found naturally at temperatures below 5°C. Its physiology and energetics were examined to understand the metabolic limitations that restrict the snow crab to these temperatures. The species is not confined to cold water because of a limited respiratory system. Routine oxygen demand can be met even at lethal temperatures of 18°C (56 mg O2kg−1h−1, with a Q10 of 2.2). Blood lactate levels remain below 1.5 mmol l−1 and actually decline slightly with temperature. Energy budgets, which were constructed from an examination of oxygen uptake, activity and food consumption in morphometrically mature male animals between 0 and 18°C, indicate that the snow crab is energetically restricted to cold water. Rising metabolic costs overtake caloric intake around 7°C. This is probably due to digestive metabolism which is temperature-sensitive. Food consumption increases up to 6°C but then falls. Crabs stop feeding above 12°C. Although the growth equation is positive between 1 and 7°C, it becomes slightly negative below 1°C. This observation is unexpected since snow crabs are commonly found between 0 and 1°C. Slight temperature changes in the natural environment may, therefore, regulate growth and reproduction in this species.

Mouse strain differences in ozone dosimetry and body temperature changes

1997 ◽  
Vol 272 (1) ◽  
pp. L73-L77 ◽  
Author(s):  
R. Slade ◽  
W. P. Watkinson ◽  
G. E. Hatch
Keyword(s):  
Body Temperature ◽  
Mouse Strain ◽  
Strain Differences ◽  
Basal Metabolism ◽  
Temperature Changes ◽  
Mean Temperature ◽  
Body Core ◽  
Mouse Strain Differences ◽  
Delivered Dose

Strain differences in susceptibility to inhaled ozone (O3) have been observed in mice, with C57BL/6J (B6) mice reported to be more sensitive than C3H/HEJ (C3) mice when exposed to equal concentrations of O3. To determine whether differences in the delivered dose of O3 to the lung could help explain these differences, C3 and B6 mice were exposed to 18O-labeled ozone (18O3), and the resulting 18O concentrations in pulmonary tissues were monitored as an indicator of O3 delivered dose. Body core temperatures (Tco) of similarly treated mice were measured during O3 exposures (using surgically implanted temperature probes) in an effort to correlate lung O3 dose to changes in basal metabolism. Immediately after exposure to 18O3, C3 mice had 46% less 18O (per mg dry wt) in lungs and 61% less in tracheas than B6 mice. Nasal 18O tended to be lower in the C3 mice, but these differences were not significant. Although both strains responded to the O3 exposure with significant decreases in Tco, C3 mice had a 70% greater mean temperature x time product decrease during the exposure than B6 mice. These results suggest that the strain differences in O3 susceptibility may be due to differences in O3 dose to the lung, which may be related to differences in the ability of the mice to lower their Tco in response to O3 exposure.

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