scholarly journals The Influence of Boiling on the Streamlined Body Drag Force and Falling Velocity

2021 ◽  
Vol 11 (4) ◽  
pp. 1562
Author(s):  
Linas Paukštaitis ◽  
Sigitas Kilikevičius ◽  
Ramūnas Česnavičius ◽  
Kristina Liutkauskienė ◽  
Tadas Ždankus
Keyword(s):  
Body Temperature ◽  
Water Temperature ◽  
Drag Force ◽  
Water Channel ◽  
Saturation Temperature ◽  
The Body ◽  
Transfer Model ◽  
Initial Moment ◽  
Streamlined Body ◽  
Different Temperatures

This article presents the results of numerical investigation of the influence of the streamlined body temperature on drag force and on the falling velocity in a water channel. The experimental data reflecting the cooling dynamics and body temperature influence on the falling velocity are presented as well. k − ε turbulence model and homogenous heat transfer model were chosen for the numerical 3D simulation. Drag force changes induced by the alteration of the body temperature were investigated. Velocity of the streamlined body under different temperatures of water was investigated experimentally, and the results were compared to the data obtained during the numerical simulation. The increase of the falling velocity and decrease of drag force were found to have been affected by the increase of the body temperature, which had influence on the change of the water parameters (density, phase, etc.) near the surface of the body. Simulation showed that the drag force and a velocity also depended on the water temperature. The drag force of the streamlined body decreased by 32% in comparison to the cold body for the body temperature equal to 150 °C and water temperature close to the saturation temperature (98 °C). Experimentally, it was determined that the velocity of the streamlined body covered by vapor film depended on the falling time and increased by 10–30%. Velocity difference was very small for the cold and hot bodies at the initial moment of the drop; however, it reached 20% and more after 0.3 s of the falling process.

ON THE SURVIVAL AND METABOLISM OF NORMAL AND HYPOTHERMIC PRE-VIABLE HUMAN FOETUSES

1961 ◽  
Vol 23 (1) ◽  
pp. 69-77 ◽  
Author(s):  
S. KULLANDER ◽  
B. SUNDÉN
Keyword(s):  
Body Temperature ◽  
Survival Time ◽  
Glycogen Content ◽  
Adrenal Glands ◽  
Early Stage ◽  
The Body ◽  
Protein Nitrogen ◽  
Different Temperatures ◽  
Human Foetuses ◽  
General Reduction

SUMMARY A total of twenty-three human pre-viable foetuses (7–400 g.) were removed by abdominal hysterotomy (legal abortions) and studied during survival in an anoxic state at different temperatures. The duration of survival, as judged by ECG waves, at 37° c was about 3 hr.; it was longer for female foetuses than for males, and longer for large foetuses than for small ones. General reduction of the body-temperature to 4° c during periods varying between 30 min. and 6 hr. with subsequent rewarming to and maintenance at 37° c increased the survival time by a further 1–2 hr. The blood sugar did not decrease either during the period of survival or during hypothermia, but the non-protein nitrogen increased, while acidosis and hyperkalaemia developed. The glycogen content of the liver decreased during the anoxic period of survival and diminished further during hypothermia. The adrenal glands produced adrenaline in addition to noradrenaline during the anoxic phase, and this may occur in a very early stage of intrauterine life.

Digestion in Ascidians and the Influence of Temperature

1929 ◽  
Vol 6 (3) ◽  
pp. 275-292
Author(s):  
N. J. BERRILL
Keyword(s):  
Enzyme Activity ◽  
Body Temperature ◽  
Digestive Enzymes ◽  
Alimentary Canal ◽  
The Body ◽  
Maximum Efficiency ◽  
Bile Pigment ◽  
Optimum Temperature ◽  
Different Temperatures ◽  
Pass Through

1. The mechanism of feeding and digestion in the Pyurid Ascidians Tethyum pyriforme americanum and Boltenia ovifera is described. 2. The structure and histology of the "liver" is described and it is shown that it is primarily an organ of secretion. 3. It is found that the only digestive enzymes are those poured into the gut by the liver, and consist of a powerful amylase, a protease, a very weak lipase, and also an invertase, a maltase, and a lactase. 4. The brownish pigment of the liver gives reactions with acids somewhat like those of bile pigment. There is no trace of bile salts, however, nor of cholesterol. 5. The amylase has an activity range from pH 6.0 topic pH 8.5 with an optimum near pH 7.5. The protease is active from pH 6.0 to above pH 10.0. A similar protease is secreted by Molgula citrina and Ascidia prunum. 6. The relative strengths of the amylase and protease are compared, the amylase being very much the stronger. 7. While experiments of brief duration indicate an optimum temperature for enzyme activity above 40° C, the more prolonged the experiments the lower does the optimum become. Whatever the optimum may be after an experiment of 2 hours' duration, it falls about 20° C. during the next 45 hours, if the experiments be so prolonged. 8. At 15° C. and at 10° C. the food takes about 35 and 55 hours respectively to pass through the alimentary canal, and at 50 C. somewhere between 70 and 90 hours. These temperatures approximately cover the normal range in temperature of the environment, and therefore of the animal itself. 9. From experiments lasting 33 hours the optimum temperature for enzyme activity was found to be about 17° C.; that is, within one or two degrees of the body temperature. From experiments lasting 57 hours the optimum temperature was found to be about 13° C ; that is, within three degrees of the body temperature. 10. These temperature optima not only represent the relative amounts of substrate converted at different temperatures, but also represent the absolute amounts converted and convertible. 11. The enzymes, amylase and protease, are two-thirds to three-quarters destroyed during their period of activity within the alimentary canal of the animal, and in order to utilise the remainder the digestion mixture would have to be retained within the canal for twice as long a time. 12. Therefore it seems probable that the organism in making such a compromise between a high activity of the enzyme and its economical use is working to a maximum efficiency; and it is possible that a permanent increase in the stability of the digestive enzymes would be turned to advantage through a more prolonged retention of the food within the gut.

scholarly journals Thermal Field Analysis of Two Kinds of Suspended Moxibustion

2021 ◽  
Author(s):  
Bo Zhang ◽  
Shan Huang ◽  
Hanrui Zhang ◽  
Haiyan Tu
Keyword(s):  
Body Temperature ◽  
Temperature Change ◽  
Thermal Field ◽  
Subcutaneous Tissue ◽  
Skin Surface ◽  
The Body ◽  
Field Analysis ◽  
Transfer Model ◽  
Suspended Moxibustion ◽  
Mild Moxibustion

Abstract Background: Moxibustion has been widely used in Chinese medicine treatment and health care, it is necessary to study the mechanism and characteristics of moxibustion treatment. The warm effect of moxibustion is closely related to the therapeutic effect. Studying the distribution and change of thermal field is an effective way to understand the mechanism of moxibustion. Methods: The finite element analysis software COMSOL was used to establish the heat transfer model to simulate the whole moxibustion process. Two kinds of suspended moxibustion methods, including mild moxibustion and sparrow-pecking moxibustion, were used to perform moxibustion trial at Zusanli acupoint (ST36) of volunteers, with Institutional Review Board (IRB) approval, and the thermal field on the skin surface was detected with an infrared thermometer. Results: Moxibustion method and moxibustion distance are the factors that affect the temperature change. The temperature rising speed of mild moxibustion was slower than that of sparrow-pecking moxibustion. When the moxibustion distance changes, the temperature changes obviously. If the moxibustion distance does not change, the body temperature will continue to rise slowly. If the distance increases, the body temperature will show a downward trend. On the contrary, it goes up. The thermal fields of mild moxibustion and sparrow-pecking moxibustion were distributed in concentric circles around Zusanli. After natural cooling, the temperature of subcutaneous tissue was higher than that of epidermis.Conclusion: The speed of skin temperature change is affected by the method of moxibustion. The temperature field characteristics formed on the skin surface and acupoint are affected by the moxibustion distance and the moxibustion duration. Moxibustion will produce warm heat stimulation to the subcutaneous tissue.

scholarly journals Effects of adhesive systems at different temperatures on the shear bond strength of orthodontic brackets

2019 ◽  
Vol 13 (2) ◽  
pp. 103-108
Author(s):  
Serdar Akarsu ◽  
Suleyman Kutalmış Buyuk ◽  
Ahmet Serkan Kucukekenci
Keyword(s):  
Body Temperature ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
The Body ◽  
Orthodontic Brackets ◽  
Effect Of Temperature ◽  
Adhesive Systems ◽  
Significant Difference ◽  
Different Temperatures

Background. The temperature might affect the physical and mechanical properties of adhesive materials by reducing the polymerization rate. The present study aimed to evaluate the effect of temperature on the shear bond strength of metallic orthodontic brackets using various adhesive resin systems. Methods. Extracted human premolar teeth were randomly assigned to 8 groups (n=10) for bonding with the two available orthodontics adhesive systems (Transbond XT and NeoBond) at different temperatures: refrigeration temperature (4°C), room temperature (20°C), human body temperature (36°C) and high temperature (55°C). The shear bond strength (SBS) test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min. The adhesive remnant index (ARI) was assigned to the fractured orthodontic brackets. Data were analyzed with one-way ANOVA, post hoc Tukey tests and independent t-test. Results. Transbond XT exhibited higher SBS values compared to Neobond at all the tested temperatures; however, a statistically significant difference was not observed (P>0.05). The SBS results were minimum at 4°C and maximum at 36°C in both the adhesive groups (P<0.05). Conclusion. Pre-heating orthodontic adhesives up to the body temperature prior to bonding the brackets in orthodontic treatment increased the bond strength of orthodontic brackets.

HEAT TRANSFER MODEL FOR PREDICTING SURVIVAL TIME IN COLD WATER IMMERSION

2005 ◽  
Vol 17 (04) ◽  
pp. 159-166 ◽  
Author(s):  
F. TARLOCHAN ◽  
S. RAMESH
Keyword(s):  
Heat Transfer ◽  
Water Temperature ◽  
Survival Time ◽  
Cold Water ◽  
Water Immersion ◽  
Thermal Conductance ◽  
Cold Water Immersion ◽  
The Body ◽  
Complex Nature ◽  
Transfer Model

In the present paper a heat transfer (HT) model to estimate survival time of individual stranded in cold water such as at sea is proposed. The HT model was derived based on the assumption that the body specific heat capacity and thermal conductance are not time dependent. The solution to the HT model simulates expected survival time as a function of water temperature, metabolism rate, skin, muscle and fat thickness, insulation thermal conductivity and thickness, height and weight of the subject. Although, these predictions must be considered approximate due to the complex nature of the variables involved, the proposed HT model can be employed to determine supplemental body insulation such as personal protective clothing to meet a predefined survival time in any given water temperature. In particular, the results obtained are useful as a decision aid in search and rescue mission in predicting survival time for shipwreck victims at sea.

scholarly journals 0518 Sleep Facilitation by Artificial Carbonated Bathing in Healthy Elderly; EEG, Core, Proximal, and Distal Temperature Evaluations

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A198-A198
Author(s):  
S I Uemura ◽  
T Kanbayashi ◽  
A Imanishi ◽  
Y Terui ◽  
M Satake ◽  
...  
Keyword(s):  
Body Temperature ◽  
Water Temperature ◽  
Skin Temperature ◽  
The Body ◽  
Hot Water ◽  
Elderly Subjects ◽  
Brain Wave ◽  
Healthy Elderly ◽  
Significant Difference ◽  
Light Sleep

Abstract Introduction Bathing, especially with hot spring with various mineral compositions, is known to facilitate / improve sleep by warming the body. Artificial carbonated bathing (ACB) is known to keep the body warm too. Previous our study examined that ACB before sleep more specifically affected body temperature and sleep on healthy young subjects. In this study, we evaluated the effects of usual (plain hot water; PH) and artificial carbonated bathing, on sleep using clinical thermometers and EEG in healthy elderly subjects. Methods Nine healthy elderly women (average age 71.3 years old) were divided into 2 groups ACB (858 ppm, Awacomachi, Danrei Co.) and PH with a week interval. Subjects soaked in the bath (38 C degree) deep enough their chests touched the water for 10 min. From the time they finished bathing to the next morning, we measured their distal skin temperature (top side of the foot), proximal skin temperature (lower part of the clavicle) and EEG using a single channel portable device (Brain wave sensor, Proassist Co.). Subjects were told to sleep from 23:00-6:00. As the same time, subjects were examined with visual analog scale (VAS) and clinical flicker fusion test (CFF). Results There was no significant difference in body temperature (proximal, distal, distal-proximal temperature gradient: DPG) before and during sleep between ACB and PH. The condition of the ACB tended to have less light sleep compared to PH (150min vs 201min, p=0.08), but there was no significant difference in the SWS (44.1min vs 39.1min, ns), EEG delta power analysis, VAS and CFF. In the previous study, bathing was performed for 15 min at a water temperature of 40 C degree, but this condition was considered to be a high risk for the elderly. The reason why there was no significant difference in body temperature. The effects of ACB were not fully demonstrated due to changes in hot water temperature and bathing time. Conclusion The effect of ACB on the body temperature of healthy elderly people could not be confirmed. However, a tendency to reduce light sleep was observed. Support This work was supported by JSPS KAKENHI Grant Number JP19K11294

Theoretical Predictions of Body Tissue and Blood Temperature During Cold Water Immersion Using a Whole Body Model

2013 ◽  
Author(s):  
Anup K. Paul ◽  
Swarup A. Zachariah ◽  
Liang Zhu ◽  
Rupak K. Banerjee
Keyword(s):  
Body Temperature ◽  
Core Temperature ◽  
Cold Water ◽  
Water Immersion ◽  
The Body ◽  
Stress Conditions ◽  
Body Tissue ◽  
Whole Body ◽  
Transfer Model ◽  
Blood Temperature

Understanding the thermal response of the human body under various environmental and thermal stress conditions is of growing importance. Calculation of the core body temperature and the survivability of the body during immersion in cold water require detailed modeling of both the body tissue and the time-dependent blood temperature. Predicting body temperature changes under cold stress conditions is considered challenging since factors like thickness of the skin and blood perfusion within the skin layer become influential. Hence, the aim of this research was to demonstrate the capability of a recently developed whole body heat transfer model that simulates the tissue-blood interaction to predict the cooling of the body during immersion in cold water. It was shown that computed drop in core temperature agrees within 0.57 °C of the results calculated using a detailed network model. The predicted survival time in 0 °C water was less than an hour whereas in 18.5 °C water, the body attained a relatively stable core temperature of 34 °C in 2.5 hours.

scholarly journals Experimental Study on the Use of Thermoelectric Generators in Harvesting Human Body Heat

2018 ◽  
Vol 7 (4.35) ◽  
pp. 264
Author(s):  
N. Rosli ◽  
H. Mohamed
Keyword(s):  
Body Temperature ◽  
Human Body ◽  
Electrical Energy ◽  
The Body ◽  
Output Resistance ◽  
Running Activity ◽  
Humid Region ◽  
Human Body Temperature ◽  
Different Temperatures ◽  
Body Heat

The objective of this work is to investigate the potential use of a thermoelectric generator (TEG) in harvesting human body heat at four body locations namely forehead, wrist, palm and calf for different human activities in Malaysia. Important parameters for this experiment are human body temperature, room temperature, output voltage, output resistance and output power. A healthy male and female perform a series of activities including resting, walking and running for 10 minutes in an indoor setting. Results indicate the relevant effects of temperature and movement on producing power from human body heat. Different parts of the body have different temperatures, thus creating different output powers. Results show that as the movement increases, the human body temperature and the amount of energy harvested also increase. It is also observed that forehead provides the highest amount of power generated during running activity. When the body temperature is above 35 °C, the TEG can generate power more than 5.0 mW. The highest power generated during the experiment is 9.5 mW. Even though Malaysia is known as a hot and humid region, TEGs can be feasibly utilized as a wearable device that converts human heat energy into electrical energy.

Feeding of Some Great Lakes Fishes at Low Temperatures

1968 ◽  
Vol 25 (6) ◽  
pp. 1199-1218 ◽  
Author(s):  
Allen Keast
Keyword(s):  
Body Weight ◽  
Water Temperature ◽  
Low Temperatures ◽  
Field Studies ◽  
Body Cavity ◽  
The Body ◽  
Lepomis Gibbosus ◽  
Pomoxis Nigromaculatus ◽  
Ictalurus Nebulosus ◽  
Different Temperatures

Field studies on low temperature feeding in freshwater fishes were carried out as follows: (1) Fish Lake, near Picton, Ontario, January–March 1966 and 1967, 1200 fish netted from under the ice at a temperature of 4 C; (2) Little Cataraqui Creek near Collins Bay, April 1966, groups of fish (total, 544 individuals) netted at intervals of several days as the water temperature rose from 6.8 to 11 C; (3) Upper Jones Creek, near Mallorytown, two extensive collections (total, 1005 individuals) made between April 27 and 30, 1966 (at a water temperature of 8 C), and May 15 and 17 (15 C). The following findings resulted.Some members of all six species in Fish Lake contained food but the percentage varied from 50% in Umbra limi down to 10% in Fundulus diaphanus. Hence feeding was erratic. Within species the smaller individuals invariably contained more food (0.005–0.02 g of alimentary contents per gram body weight) than larger fish (0.002–0.005). The same was true of smaller, as compared with larger, bodied species, with the exception of F. diaphanus.After the thaw in Little Cataraqui Creek active feeding commenced at different temperatures in the various species: it was already under way at 6.5 C (when the study started) in Ictalurus nebulosus and Pomoxis nigromaculatus, but did not start in Lepomis gibbosus and Ambloplites rupestris until the water temperature reached 8.5 C. Prior to this the stomachs of species were shrunken, mucous-filled, and drawn far forward in the body cavity. Few Perca flavescens, active winter feeders, fed in April, immediately prior to spawning.In most of the Jones Creek fishes there was a marked increase in weight of alimentary contents (gram per gram body weight) between 8 and 15 C. Exceptions were the larger Semotilus atromaculatus, which were than spawning, and U. limi and Eucalia inconstans, which were sampled before their peak daily feeding times. To the differences in weights of alimentary contents at 8 and 15 C must be added accelerated digestion rates at 15 C.In all the waterways studied the fish consumed a much smaller range of prey items at low temperatures than at higher ones. This applied in midwinter, compared with summer, in Fish Lake, and in April and October, compared with summer, in Jones Creek. A few foods, e.g. chironomid larvae and Cladocera, were especially prominent in the diet at low temperatures, and species food specializations were suppressed. There was probably not, however, any increase in interspecific competition at temperatures approaching zero, because of the relatively low metabolic requirements of the fish.

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