Steady-state temperature distribution in man

Wissler, Eugene H.

doi:10.1152/jappl.1961.16.4.734

Cited by 121 publications

(40 citation statements)

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“…The Wissler human thermoregulation model has been under continuous development and refinement for more than 50 yr [54,55]. As local colleagues at the University of Texas, we have taken advantage of the opportunity to collaborate in various past studies [56].…”

Section: Modeling and Simulation Of Thermoregulationmentioning

confidence: 99%

Heat Transfer in Health and Healing1

Diller

2015

Journal of Heat Transfer

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1Our bodies depend on an exquisitely sensitive and refined temperature control system to maintain a state of health and homeostasis. The exceptionally broad range of physical activities that humans engage in and the diverse array of environmental conditions we face require remarkable strategies and mechanisms for regulating internal and external heat transfer processes. On the occasions for which the body suffers trauma, therapeutic temperature modulation is often the approach of choice for reversing injury and inflammation and launching a cascade of healing. The focus of human thermoregulation is maintenance of the body core temperature within a tight range of values, even as internal rates of energy generation may vary over an order of magnitude, environmental convection, and radiation heat loads may undergo large changes in the absence of any significant personal control, surface insulation may be added or removed, all occurring while the body's internal thermostat follows a diurnal circadian cycle that may be altered by illness and anesthetic agents. An advanced level of understanding of the complex physiological function and control of the human body may be combined with skill in heat transfer analysis and design to develop life-saving and injury-healing medical devices. This paper will describe some of the challenges and conquests the author has experienced related to the practice of heat transfer for maintenance of health and enhancement of healing processes.

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Section: Modeling and Simulation Of Thermoregulationmentioning

confidence: 99%

Heat Transfer in Health and Healing1

Diller

2015

Journal of Heat Transfer

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“…For calculation of the heat transfer coefficient, we used the same approaches and equations as described in detail by Wissler [1961]. Equation 2 was solved numerically using the finite difference method.…”

Section: Thermal Modelsmentioning

confidence: 99%

Local heating of human skin by millimeter waves: Effect of blood flow

Алексеев

Radzievsky

Szabó

et al. 2005

Bioelectromagnetics

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We investigated the influence of blood perfusion on local heating of the forearm and middle finger skin following 42.25 GHz exposure with an open ended waveguide (WG) and with a YAV mm wave therapeutic device. Both sources had bell-shaped distributions of the incident power density (IPD) with peak intensities of 208 and 55 mW/cm(2), respectively. Blood perfusion was changed in two ways: by blood flow occlusion and by externally applied vasodilator (nonivamide/nicoboxil) cream to the skin. For thermal modeling, we used the bioheat transfer equation (BHTE) and the hybrid bioheat equation (HBHE) which combines the BHTE and the scalar effective thermal conductivity equation (ETCE). Under normal conditions with the 208 mW/cm(2) exposure, the cutaneous temperature elevation (DeltaT) in the finger (2.5 +/- 0.3 degrees C) having higher blood flow was notably smaller than the cutaneous DeltaT in the forearm (4.7 +/- 0.4 degrees C). However, heating of the forearm and finger skin with blood flow occluded was the same, indicating that the thermal conductivity of tissue in the absence of blood flow at both locations was also the same. The BHTE accurately predicted local hyperthermia in the forearm only at low blood flow. The HBHE made accurate predictions at both low and high perfusion rates. The relationship between blood flow and the effective thermal conductivity (k(eff)) was found to be linear. The heat dissipating effect of higher perfusion was mostly due to an apparent increase in k(eff). It was shown that mm wave exposure could result in steady state heating of tissue layers located much deeper than the penetration depth (0.56 mm). The surface DeltaT and heat penetration into tissue increased with enlarging the irradiating beam area and with increasing exposure duration. Thus, mm waves at sufficient intensities could thermally affect thermo-sensitive structures located in the skin and underlying tissue.

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“…However, a great variety of general problems may already be tested using a onedimensional four-layer cylinder-model of the human body as it was used in various versions by several authors (e.g. Wissler 1961;Stolwijk and Hardy 1966;Werner 1975Werner , 1977. Such problems, which will be outlined and solved in this paper, are:…”

Section: Introductionmentioning

confidence: 99%

Closed loop control of human body temperature: results from a one-dimensional model

Buse

Werner

1989

Biol. Cybern.

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A one-dimensional model of human thermo-regulation is used to solve a variety of basic problems in determining an adequate structure of the controller for metabolic heat production, skin blood flow and sweat production. Assuming one integrated central and one integrated peripheral afferent signal the controller parameters are evaluated by analysis of the control performance. Based on a validation by experimental results this allows the determination of a first optimized set of values for controller gains and weight of skin temperature feedback. Furthermore we analyse the effect of inhomogeneous distribution of heat production and blood flow, the influence of body fat content, of controller gains, of weight of skin temperature feedback and of depth of peripheral receptors on the dynamic performance. Increase of peripheral blood flow in particular evokes essentially both an increase of energy requirement in the cold and a quicker system response. Differing rates of increase of metabolic heat production are the consequence of differing body fat content. The weight of skin temperature feedback can be limited to 5...20%, because values outside this range evoke dynamic responses incompatible with the experiments. The actual value can only be determined if there is a correct assumption for the depth of the skin receptors. The use of measured superficial skin temperatures brings about an underestimation of the peripheral afferent signal. Of the controller gains it is primarily the gain of the metabolic controller which affects the dynamic response of the system. The experimental fact of a delayed onset of sweat production after a transition from cold to heat is the consequence of a high gain of the vasomotor system.

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Steady-state temperature distribution in man

Cited by 121 publications

References 0 publications

Heat Transfer in Health and Healing1

Heat Transfer in Health and Healing1

Local heating of human skin by millimeter waves: Effect of blood flow

Closed loop control of human body temperature: results from a one-dimensional model

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