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The paper presents a thermoelectric device capable of simultaneously measuring the temperature and density of heat fluxes on the surface of a human body with the help of a developed thermoelectric sensor with a thermostated free surface, thus excluding the effect of ambient temperature on the sensor readings. A special computer programme has been developed for processing the measurement results by way of accumulating and reproducing them in a specified form on a personal computer, which enables monitoring the temperature and thermal state of a human in real time. The specific features of the device design and its technical characteristics are given.

At present chemical sources of electricity are used as power supplies for low-powered electronic equipment. Despite continuous quality improvement (CQI) of chemical sources of electricity they still have some critical faults, such as: relatively high specific overall dimensions, presence of self-discharge, short life and limited shelf life under low temperature storage. Moreover, the chemical source of electricity production is power-consuming, costly and environmentally harmful. The plurality of facts given above stipulates the search for new sources of electric energy eliminating the faults chemical ones possess. Therefore, thermoelectric power supply sources are especially prospective in this respect as thermoelectric generators in general have a long operational life, they are reliable for use in extreme conditions and do not need being changed periodically. It is a well-known fact that thermoelectric converter efficiency depends on the load resistance and the converter resistance matching, which are stipulated by such converter design. The results of calculations of a thermoelectric converter for a medical thermometer power supply are presented in this paper. The authors define a rational design of such a converter which is limited by technological complexity of small-size legs fabrication, on the one hand, and with the converter overall dimensions, on the other hand. The study carried out has shown the expediency of a thermoelectric converter application for various operational modes to provide an electronic medical thermometer power supply, particularly in the unmatched load mode with the converter efficiency dropping down five to tenfold. The work confirms the possibility of a thermoelectric converter of human body application for an electronic medical thermometer power supply.

The theoretical aspects of evaluating the electrical resistance of a thermoelectric leg–metal contact are considered. A physical model of such a contact and methods for calculating the main components of the contact resistivity, namely, the resistivity of the interfacial layer and the resistivity related to the transfer of charge carriers through a potential barrier at the boundary between a material of the thermoelectric leg and a metal, are proposed. The contact resistivity for thermoelectric legs made of Bi2Te3 based materials with deposited antidiffusion nickel layers is calculated. It was established that the contact resistivity in such thermoelements reaches a value from 0.25 × 10−6 to 2.5 × 10−6 Ω cm2 and depends on the temperature and interfacial layer thickness. It is demonstrated that the findings are in good agreement with the known experimental values of contact resistivity. [ABSTRACT FROM AUTHOR]

Computer methods for the description of the anisotropic thermoelement (AT) properties with regard to all necessary model approximations have been elaborated. Configurations of eddy thermoelectric currents in the anisotropic thermoele-ment caused by current contacts have been found. The pro-perties of the AT with regard to temperature dependences of material properties, contact resistances and current contacts have been determined for concrete cases. Optimal dimensions of current contacts have been found. The optimization of AT construction allowed to increase its efficiency by 15%.

Background: Heat exchange characteristics include not only temperatures and temperature distribution, but also heat flux (HF). Purpose: To examine temperature of and density of HF from the ocular surface in the eyes of patients with diabetic retinopathy (DR). Material and Methods: Sixty-two patients (123 eyes) with DR were under observation. Of these, 28 (55 eyes) and 34 (68 eyes) were diagnosed with non-proliferative DR (NPDR) and proliferative DR (PDR), respectively. They underwent a general clinical examination and measurements of temperature of the external corneal surface and density of HF from the eye. In addition, all NPDR patients underwent rheoophthalmography (ROG). Results: There was a significant difference in density of HF from the ocular surface (7.3 ± 2.1 mW/cm² vs 6.3 ± 1.6 mW/cm²; p = 0.002), but not in ocular surface temperature (34.7 ± 1.3 °? vs 34.8 ± 1.1 °?; p = 0.8) between NPDR patients and PDR patients. HF density from the eye was positively correlated with the ocular blood volume coefficient (RQ; also named the rheographic coefficient) as assessed by ROG (r = 0.5; p = 0.01) for patients with NPDR. There was a relationship between the density of heat flux from the ocular surface and age of DR patients. Conclusion: Preliminary results suggest that (1) compared to the temperature of the ocular surface, the heat flux from the ocular surface better reflects the status of heat exchange in the eye, and (2) the technique might be promising as a diagnostic test for various pathological conditions involving impaired heat processes in the eye. [ABSTRACT FROM AUTHOR]

Background: Assessment of heat exchange processes in the human body is based on temperature and heat flux measurements. Today, there is no instrument for measuring the heat flux density from the eye. Purpose: To investigate the heat flux density from the ocular surface in healthy individuals using the developed thermoelectric device. Materials and Methods: The thermoelectric device for the measurement of heat flux from the eye has been developed within the framework of the partnership agreement between the Institute of Thermoelectricity and the Filatov Institute. Thirty-two healthy individuals (64 eyes) were under observation. Participants were divided into three age groups. They underwent a bilateral eye examination which included measurements of intraocular pressure, temperature of the external corneal surface, and heat flux density from the eye. Results: Mean room temperature during examination sessions was 21.3 ± 0.8 °C. In addition, mean temperature of the external ocular surface and mean heat flux density from the human eye were 34.6 ± 0.7°C and 7.7 ± 1.3 mW/cm2, respectively. We found that the heat flux density from the eye decreased with age in healthy subjects. Conclusion: The first ever thermoelectric device for real-time measuring of the heat flux density from the human eye was developed. The developed device was used to measure the heat flux density from the eye in healthy subjects, and to demonstrate the relationships of this characteristic with the temperature of the external ocular surface and subject age. [ABSTRACT FROM AUTHOR]

Background: Intraoperative intraocular media and irrigation fluid temperature monitoring is not performed during vitreoretinal surgery in current clinical practice. Purpose: To investigate intraoperative changes in intraocular temperature at the major steps of vitreoretinal surgery with irrigating solutions differing in temperature. Materials and Methods: Thirty-nine patients (39 eyes) were under observation before, during and after vitrectomy. Group 1 (20 patients; 20 eyes) and Group 2 (19 patients; 19 eyes) differed with respect to the baseline temperature (24.2 ± 0.52 °, or 10.3 ± 1.1 °?, respectively) of the irrigating fluid. Room air temperature, irrigating fluid temperature, patient's body temperature, blood pressure, heart rate and blood oxygen saturation, vitreous temperature, and duration of every step of the vitreoretinal procedure were recorded in all cases. Results: Vitrectomy with 24°C or 10°C irrigating solutions resulted in a substantial decrease in temperature in vitreous compartments to the level of moderate or deep hypothermia, respectively. In addition, immediately after vitrectomy, the lowest temperatures were found in the anterior vitreous, and were 30.1 ± 0.45 °? for the 24°C group and 24.37±0.52 °? for the 10°C group. Moreover, after additional surgical manipulations, in the presence of discontinued irrigation, the temperatures in the vitreous compartments were found to gradually increase. Conclusion: Vitreoretinal surgery is performed under conditions of induced uncontrolled local hypothermia, which requires intraoperative monitoring of intraocular temperature and irrigating solution temperature. During a vitroretinal procedure lasting up to 30 minutes, the intraocular contents may be safely cooled to the level of deep hypothermia. [ABSTRACT FROM AUTHOR]