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.
Optimal selection of thermowells
Abstract Thermowells are universally used in the hydrocarbon industries, with little thought as to their selection. This paper gives a method of optimising the selection, balancing hydraulic and vibration requirements against static and dynamic errors, and indicating likely levels of error for screwed, flanged and vanStone style wells. It also considers the alternative of externally mounting and insulating the thermal element.
Risks of hyperthermia associated with hot tub or spa use by pregnant women.
There are a limited number of human studies linking hot tub or spa use during early pregnancy to increased risks for neural tube defects (NTDs) or spontaneous abortion. However, these data can be considered in the context of human studies that have demonstrated an association between high maternal fever in early pregnancy and NTDs. In addition, there is a large volume of animal literature suggesting that, regardless of the heat source, an elevated core maternal temperature at or above the threshold of 2 degrees C over baseline, as well as timing and duration of exposure, are the critical factors in conferring risk. Therefore, the potential for hot tub or spa use to increase core maternal body temperature to risky levels and thus increase the risk for NTDs is likely. A woman who knows or who may not yet be aware that she is pregnant should be advised of the recommended limits of exposure. She should also be aware of the possible variability in hot tub or spa temperature readings and be able to accurately monitor maximum water temperature in the hot tub or spa so that her body temperature can be maintained below 38.9 degrees C.