Search

Increased temperature in humans is the symptom of many infectious diseases and it is thus an important diagnostic tool. Infrared temperature measurement methods have been developed and applied over long periods due to their advantage of non-contact and fast measurements. This study deals with a statistical evaluation of the possibilities and limitations of infrared/thermographic human temperature measurement. A short review of the use of infrared temperature measurement in medical applications is provided. Experiments and statistics-based evaluation to confirm the expected accuracy and limits of thermography-based human temperature measurement are introduced. The results presented in this study show that the standard deviation of the thermographic measurement of the eyes maximum temperature was 0.4–0.9 °C and the mean values differences from the armpit measurement were up to 0.5 °C, based on the used IR camera, even though near ideal measurement conditions and permanent blackbody correction were used. It was also shown that a certain number of outliers must be assumed in such measurements. Extended analyses including simulations of true negative/false positive, sensitivity/specificity and receiver operating characteristics (ROC) curves are presented. The statistical evaluation as well as the extended analyses show that maximum eyes temperature is more relevant than a forehead temperature examination. [ABSTRACT FROM AUTHOR]

[Display omitted] • Human infrared thermography temperature measurement. • Enhanced precision thermographic device with an internal calibrating element. • Human temperature measurement statistical study. Elevated temperature of humans can be an indicator of many diseases and its measurement is therefore a common diagnostic tool. Thermographic methods allow of non-contact, fast and automated measurement. Their main disadvantage, however, is a lower accuracy than is usually required for the measurement of the core body temperature. A thermographic device with an internal calibrating element for enhanced precision measurement is introduced in this study. It is a compact device for face/eyes temperature diagnostics, which uses a micro-bolometer based infrared detector and the active calibrating element. The calibrating element is embedded in the device casing and heated to a temperature close to the body core temperature 37 °C. It allows a high precision body temperature measurement with an accuracy comparable with a thermographic measurement enhanced by an external blackbody, but it keeps the device very compact and mobile. The device and its function are described in the paper. Results of verification and calibrating experiments with a black body are presented. A fairly good standard deviation of about ± 0.2 °C is demonstrated. The mean eyes maximum temperature 35.77 ± 0.42 °C obtained by an evaluation of a long-term temperature measurement on faces of human testers confirmed accuracy and effectivity comparable with a standard thermographic devices measurement enhanced by and external blackbody. [ABSTRACT FROM AUTHOR]

• A h-BN based layered 2D interface was used for the cooling of nanoscale hot-spots. • Heat dissipation was enhanced with anisotropic heat transfer characteristics of h-BN. • The measurement was conducted with minimized convective and radiative heat transfer. • Current reduction induced by self-heating was resolved in high power devices. • At least 20 K reduction in hot-spot temperature was observed at 12.5 Wmm−1 power density. Thermal management of integrated circuits (ICs) is becoming increasingly important as the feature-size of transistors is now comparable to the phonon mean free path, and the power density is reaching a critical level. The thermal effect is especially pronounced in 3D ICs with limited heat dissipation paths due to stacked transistors with insulators interposed between them. Hexagonal boron nitride (h-BN) is an insulating 2D material with a strong anisotropy in its heat-conducting property; the heat transfer coefficient is very high in the lateral direction, rivaling that of copper, but relatively low in the vertical direction. In this work, we studied the heat dissipation efficiency of integrated h-BN gate dielectrics with varying thicknesses in an environment similar to that of a stacked IC. High-power GaN transistors were interposed between thick insulators to emulate the hotspot propagation in a confined environment with minimized convective and radiative heat transfer. Devices were compared via in situ thermographic imaging, and at least a 20 K decrease in hotspot temperature was observed at the power density of 10 to 12.5 Wmm−1. Importantly, the drain current which was suppressed due to the self-heating effect was restored to its normal level after the heat conduction rate increased. [ABSTRACT FROM AUTHOR]

Estimating the additional power losses caused by an inter-laminar short circuit in electromagnetic devices using thermal measurements depends on many parameters such as thermal conductivity, heat capacity, convective heat coefficient, and size of the fault points. This paper presents a method for estimating these parameters using experimental measurement and a numerical model. The surface temperature rise due to inter-laminar short circuit fault was obtained using an infrared camera. Based on the initial temperature rise method, the least square non-linear approximation technique was used to determine the best fitting parameters of the fault region from the numerical model. To validate the results obtained, the fault region temperature rise and the total loss of the experimental sample were compared with the numerical model using the obtained parameters for different current supply conditions. The study shows that surface temperature distribution can be used to estimate the inter-laminar short circuit fault parameters and localized losses. [ABSTRACT FROM AUTHOR]

This article presents the research studies aimed at identifying the behavior of expanded polystyrene with the addition of graphite in the conditions of exposure to solar radiation. For this purpose, a series of in situ tests and laboratory studies were carried out. Three types of material were tested, i.e. expanded polystyrene (EPS) (white polystyrene), polystyrene with the addition of graphite (gray polystyrene) and two-layer polystyrene (gray bottom layer and white top layer). Temperature distributions on the surfaces of the panels in field and laboratory conditions were determined. The distributions of temperature were recorded at varied wind impact (field conditions and laboratory conditions) and at varied impact of solar radiation (laboratory conditions). Based on the conducted experiments, differences in temperature distribution on the surfaces of the tested panels were determined. In addition, geometric changes and deformation levels of the tested white and gray expanded polystyrene panels exposed to artificial sun radiation were determined in laboratory conditions. [ABSTRACT FROM AUTHOR]