Development of a non-invasive thermometric system for fluids in pipes
In this paper a non-invasive thermometric system for the measurement of the temperature of fluids in pipes based on the dual heat flux method is presented. The proposed solution is a possible alternative to the employment of thermowells in industrial applications. The proposed sensing system, is based on the dual heat flux method, a technique used in biomedical field. The applicability of such a measurement system in the field of interest is studied taking into account its component performance and how they influence the overall system behavior. A prototype system exploiting RTD sensors with measurement accuracy lower than 1°C has been designed, obtaining performances comparable to the thermowell ones. To reach such an accuracy a dedicated front-end electronics has been developed.
Development of a new method for the noninvasive measurement of deep body temperature without a heater.
The conventional zero-heat-flow thermometer, which measures the deep body temperature from the skin surface, is widely used at present. However, this thermometer requires considerable electricity to power the electric heater that compensates for heat loss from the probe; thus, AC power is indispensable for its use. Therefore, this conventional thermometer is inconvenient for unconstrained monitoring. We have developed a new dual-heat-flux method that can measure the deep body temperature from the skin surface without a heater. Our method is convenient for unconstrained and long-term measurement because the instrument is driven by a battery and its design promotes energy conservation. Its probe consists of dual-heat-flow channels with different thermal resistances, and each heat-flow-channel has a pair of IC sensors attached on its top and bottom. The average deep body temperature measurements taken using both the dual-heat-flux and then the zero-heat-flow thermometers from the foreheads of 17 healthy subjects were 37.08 degrees C and 37.02 degrees C, respectively. In addition, the correlation coefficient between the values obtained by the 2 methods was 0.970 (p<0.001). These results show that our method can be used for monitoring the deep body temperature as accurately as the conventional method, and it overcomes the disadvantage of the necessity of AC power supply.
Carbon Dioxide Elimination from Circle Systems
Ten various circle systems were studied in model experiments. All the experiments were performed using a Waters cannister containing 675–685 g of Durasorbr̀. 300 ml of carbon dioxide were supplied to the system per min. The efficacy of these systems was expressed as the time taken to demonstrate a concentration of 0.6% carbon dioxide in the gas mixture supplied to the patient connection during each respiratory cycle. The carbon dioxide elimination was studied at a gas flow of 2, 4 and 6 1 per min. All the systems showed an effective carbon dioxide elimination for 6 h or more at a flow of 2 1. An increasing efficacy was found with increasing flow, but to a varying extent.