The Role of the Skin in Heat Transfer

1960 ◽  
Vol 82 (3) ◽  
pp. 239-241 ◽  
Author(s):  
A. M. Stoll
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Energy Balance ◽  
Functional Capacity ◽  
Heat Production ◽  
Thermal Exchange ◽  
Orderly Fashion ◽  
Fundamental Research ◽  
The Impact

The author considers lines of fundamental research and the impact of human factors in the area of thermal exchange. Logically, this area of investigation may be divided into: (a) Heat exchange between man and his environment; and (b) internal energy balance between heat production and heat loss. Very little information has been compiled in an orderly fashion concerning the skin through which heat must flow in both directions to maintain man in his environment in a functional capacity. It is therefore the purpose of this paper to consider the human skin, its dimensions and properties with respect to its role in heat transfer, and the effects of its impairment or injury.

Comparison of the performance characteristics of three generations of membrane oxygenators: Univox®, Univox® Gold™ and SpiralGold™

Perfusion ◽  
1996 ◽  
Vol 11 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Philip D Beckley ◽  
Susan M Morris ◽  
James J Smith ◽  
Jerri L McNamara ◽  
Julie A Novak
Keyword(s):  
Heat Transfer ◽  
Blood Flow ◽  
Heat Exchange ◽  
Blood Flows ◽  
Heparin Coating ◽  
Baxter Healthcare ◽  
Recent Addition ◽  
Flow Pressure ◽  
The Impact

With continuous enhancement in oxygenator design, the question is raised as to how these changes actually impact the performance of the oxygenator. The recent addition of two new oxygenators by the Bentley Division of Baxter Healthcare Corporation provided us with a unique opportunity to compare the performance of each device and isolate the impact of each design change on performance. While the basic design and flow patterns have remained the same, application of the Duraflo® II treatment has produced the Univox® Gold™ and a change in the fibre-winding technique has produced the SpiralGold™. This study compared the effects of heparin coating (Univox® to Univox® Gold™) and fibre-winding (Univox® Gold™ to SpiralGold™) on gas and heat transfer and resistance to blood flow (pressure drop). Six oxygenators of each model were evaluated utilizing an in vitro single pass circuit, which first conditioned bovine blood to the Association for the Advancement of Medical Instrumentation (AAMI) venous standards. Blood flows of 4.0, 5.0, 6.0 and 7.0 I/min, FiO2 values of 1.0, 0.8 and 0.6, and gas-to-blood flow ratios of 0.5, 1.0 and 1.5 were chosen as test variables. Data generated included oxygen transfer, carbon dioxide transfer, arterial pO2, resistance to blood flow, and coefficient of heat exchange. The results indicate that the Duraflo II treatment does not have a significant effect on gas and heat transfer or resistance to blood flow. The fibre-winding technique employed with the new SpiralGold™, however, has improved significantly gas exchange and arterial PO2 when compared with the previous Univox® models. Resistance to blood flow and coefficient of heat exchange were not affected significantly by the winding technique.

scholarly journals Role of honeycomb structure in improving the melting process of a phase change material inside a latent heat storage unit

2021 ◽  
Vol 19 ◽  
pp. 589-592
Author(s):  
M. Hariss ◽  
◽  
M. El Alami ◽  
A. Gounni
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Numerical Study ◽  
Melting Process ◽  
Honeycomb Structure ◽  
Melting Time ◽  
Storage Unit ◽  
Latent Heat Storage ◽  
The Impact

In this work, a numerical study is performed to analyze the impact of honeycomb structure on heat transfer within the PCM. The modeling is based on a transient calculation making it possible to analyze the phase change of the paraffin using the commercial software "Fluent" based on the enthalpy-porosity model. The results showed that the impregnation of a metal matrix in a rectangular enclosure helps to decrease the melting time and thus improve the heat transfer within the PCM.

scholarly journals The role of neurotransmitters in regulation of energy homeostasis and possibility of drug correction of its disturbances in obesity

2016 ◽  
Vol 13 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Ivan I. Dedov ◽  
Ekaterina A. Troshina ◽  
Natalya V. Mazurina ◽  
Marina O. Galieva ◽  
Oksana V. Logvinova
Keyword(s):  
Eating Disorders ◽  
Energy Balance ◽  
Eating Behavior ◽  
Metabolic Disorder ◽  
Energy Homeostasis ◽  
Comorbid Conditions ◽  
Non Communicable Diseases ◽  
The World ◽  
The Impact

In today's world the problem of obesity is discussed in the context of non-communicable diseases, leading to significant encumbrances on society. This article provides information about the basics of the regulation of energy balance and eating behavior. Particular attention is paid to the role of neurotransmitters, including serotonin, a metabolic disorder that is one of the suspected causes of eating disorders. Demonstrated experience in the use of sibutramine in the world, and in the Russian practice, taking into account the impact on the development of comorbid conditions and their complications.

scholarly journals Impact Analysis of Intermediate Heat Carrier on Heat Transfer in Furnace

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Cheng Li ◽  
Wei-Jun Zhang ◽  
Zhi Yi ◽  
Na Li ◽  
Kai Li
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Exchange ◽  
Heat Carrier ◽  
Impact Analysis ◽  
Analytical Calculation ◽  
General Rule ◽  
Exchange Capacity ◽  
Theoretical Point ◽  
The Impact

Intermediate heat carriers have been applied in engineering as enhanced heat transfer elements, but their theoretical analysis still needs to be improved. Therefore, an intermediate heat carrier is added to establish the quaternary model of the furnace gas under nongray radiation characteristics. Based on this model, an analytical expression of heat flux on the surface of the billet is derived. General rule of the impact of intermediate heat carrier on the thermal efficiency in the furnace can be properly derived by analytical calculation from a theoretical point of view. The results show that the longer the length of the intermediate heat carrier located at the top of the furnace, the greater the heat exchange capacity on the surface of the billet. Meanwhile, when the intermediate heat carrier is located in the center of the furnace top, the billet gets higher heat flux; the closer to both sides, the lower the heat flux. In addition, the influence that the surface emissivity of the intermediate heat carrier has on the heat transfer of the billet surface is related to the values of εg and αgw. Comparison with previous literature shows that adding intermediate heat carrier can improve the heat exchange capacity of billet.

scholarly journals On the Impact of the Dynamics of Heat Transfer of the Thermal Machine Working Fluid and Heat Sources on the Shape of the Boundary of the Set of Realizable Regimes

2019 ◽  
Vol 3 (2) ◽  
pp. 36
Author(s):  
Margarita Zaeva ◽  
Anatoly Tsirlin ◽  
Olga Didina
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Heat Engine ◽  
Energy Conversion Efficiency ◽  
Maximum Power ◽  
Working Fluid ◽  
Transfer Coefficients ◽  
The Impact

From the point of view of finite time thermodynamics, the performance boundaries of thermal machines are considered, taking into account the irreversibility of the heat exchange processes of the working fluid with hot and cold sources. We show how the dynamics of heat exchange affects the shape of the optimal cycle of a heat engine and its performance, in particular, energy conversion efficiency in the maximum power mode. This energy conversion efficiency can depend only on the ratio of the heat transfer coefficients to the sources, or not depend on them at all. A class of dynamic functions corresponding to “natural” requirements is introduced and it is shown that, for any dynamics from this class, the optimal cycle consists of two isotherms and two adiabats, not only for the maximum power problem, but also for the problem of maximum energy conversion efficiency at a given power. Examples are given for calculating the parameters of the optimal cycle for the cases when the heat transfer coefficient to the cold source is arbitrarily large, and for dynamics in the form of a linear phenomenological (Fourier heat transfer) law.

Heat Losses through Insulated Glazing Placed Horizontally or Diagonally

2019 ◽  
Vol 828 ◽  
pp. 1-8
Author(s):  
Zbigniew Respondek
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Energy Balance ◽  
Wind Speed ◽  
Weather Conditions ◽  
Calculation Model ◽  
Heat Losses ◽  
Radiative Cooling ◽  
Complex Phenomenon ◽  
Thermal Transmittance

Heat transfer through insulating glass units is a complex phenomenon. Heat exchange occurs here through conduction, convention and radiation. In practical calculations of heat losses in buildings, the declared value of the thermal transmittance (U) is most often taken into account, which is valid for vertical panes. Currently, more and more horizontal and diagonal glass partitions are made. The aim of the article is to analyze, on the basis of the adopted calculation model, the influence of the angle of glazing slope on the thermal transmittance in different weather conditions. The different wind speed and the possibility of radiative cooling were taken into account. Radiative cooling is a phenomenon manifested by a drop in temperature on the surface of horizontal and diagonal building partitions below the external air temperature. It occurs at night under a cloudless sky. It was found that in the case of horizontal or diagonal glazing heat losses increase significantly, which affects the energy balance of the building. Radiative cooling, especially in windless weather, is an additional unfavorable factor.

scholarly journals Impact of the Ayurveda Treatment Protocol in the Management of COVID -19

2022 ◽  
Vol 12 (1) ◽  
pp. 36-45
Author(s):  
Sailekha P. ◽  
Sudhikumar K B
Keyword(s):  
Infectious Disease ◽  
Treatment Protocol ◽  
Respiratory Illness ◽  
Treatment Method ◽  
Treatment Approaches ◽  
Fundamental Research ◽  
Ayurvedic Treatment ◽  
The Impact ◽  
Severe Respiratory Illness

Covid-19 is an infectious disease caused by SARS-COV-2, which can cause severe respiratory illness and complications in patients. Recognizing Ayurveda's endless possibilities for improving immunity and preventing disease progression, the Ministry of AYUSH developed and approved the Ayurvedic protocol for handling Covid-19. Even though Ayurveda practitioners have been prescribing medicines to the Covid-19 patients since approval, no studies have been reported from Kerala regarding the effectiveness of the Ayurveda Treatment approaches. Hence the School of Fundamental Research in Ayurveda designed an observational study to evaluate the impact of the Ayurveda Treatment approaches in the management of Covid -19. The study result affirms that the Ayurvedic treatment method is very effective against Covid-19 and the role of Ayurveda in addressing the Covid-19 challenge is invaluable. Key words: Covid-19, Ayurvedic protocol, School of Fundamental Research in Ayurveda.

scholarly journals NUMERICAL AND ANALYTICAL SOLUTION OF THE HEAT EXCHANGE PROBLEM

2021 ◽  
Vol 8 (44) ◽  
pp. 12
Author(s):  
Y. Chоvniuk ◽  
A. Moskvitina
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Boundary Conditions ◽  
Heat Exchangers ◽  
Conjugate Problem ◽  
Working Fluid ◽  
Round Cross Section ◽  
The Third ◽  
The Given

In this work, a numerical-analytical analysis of the solution of the conjugate problem is carried out, which most fully takes into account the actual conditions of heat transfer in tubular heat exchangers under the condition of a laminar flow of the working fluid in pipes and channels. When solving the conjugate problem, the role of the non-Newtonian properties of the indicated fluid is taken into account. The obtained quantitative estimates of the errors, which are due to the fact that the conjugacy of the problem and the indication on the wall of the boundary conditions of the third kind were not taken into account. The given conditions and criteria, the fulfillment of which reduces the problem of heat transfer under boundary conditions of the third kind to a problem under boundary conditions of the first kind.Key words: heat exchange problem, pipe with a round cross section, boundary conditions of the third and first kind, non-Newtonian fluid,  heat exchangers, heat transfer.

Heat Transfer in a Rectangular Plate Fin with Inner Circular Boundaries

1985 ◽  
Vol 9 (1) ◽  
pp. 11-18 ◽  
Author(s):  
A.K. Naghdi
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Heat Exchange ◽  
Temperature Distribution ◽  
Rectangular Plate ◽  
Orderly Fashion ◽  
Steady State Heat ◽  
Steady State Heat Transfer ◽  
Axes Of Symmetry ◽  
Class Of Functions

Employing a special class of functions, the problem of steady-state heat transfer in a rectangular plate fin with 4N* inner circular boundaries are solved. It is assumed that the outer and inner boundaries of the plate are kept at different but uniform temperatures, and that the inner boundaries are symmetrically located with respect to the axes of symmetry of the plate. However, the N* inner boundaries in each quadrant do not have to be necessarily of the same size, nor must they be located in any orderly fashion. It is also assumed that the properties of the materials involved are temperature independent. Various numerical results for the rate of heat exchange and temperature distribution are presented.

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