Surface Temperature Measurements Research Articles

Temperature‐Dependent Changes in the Normal Albedo of the Lunar Surface at 1,064 nm

AbstractOver the extreme temperature variations experienced in a single lunar day (∆T ≈ 300 K), particular minerals common to the lunar surface show spectral changes at discrete near‐infrared wavelengths in laboratory settings (Roush & Singer, 1986, 1987, https://10.1111/10.1029/JB091iB10p10301, https://10.1111/10.1016/0019-1035(87)90026-1; Singer & Roush, 1985, https://10.1111/10.1029/JB090iB14p12434). Variations in temperature can cause variations in the size and shape of crystallographic sites, which control the position, shape, and depth of crystal field absorptions. At an observation wavelength of 1,064 nm, the Lunar Orbiter Laser Altimeter (LOLA) should be highly sensitive to temperature‐dependent changes of orthopyroxene. Here we analyze temperature‐dependent spectral changes of the lunar surface as measured from orbit by LOLA. We couple LOLA measurements of normal albedo with measurements of surface temperature from the Diviner Lunar Radiometer Experiment, analyzing the maria and highlands between ±50°. We provide the first evidence of temperature‐dependent spectral changes on the lunar surface from orbital observations, finding that the majority of the surface between ±50° demonstrates a small, yet measurable, negative change in 1,064‐nm albedo with temperature (−∆R/∆T). The measurable effect is on the order of a few percent change in reflectance per ~80 K, indicating that temperature changes do not have a large effect on measurements of albedo at the sensitivity of the LOLA instrument. Stronger −∆R/∆T values tend to be associated with regions with elevated orthopyroxene, and the maria typically have higher levels of orthopyroxene and stronger −∆R/∆T values than the highlands. Our results suggest that single‐wavelength lasers may be powerful tools for understanding the distribution of particular minerals on the lunar surface.

High reliability thermistor probes for early detection of breast cancer using skin contact thermometry with thermal imaging

Early detection and wide spread screening of breast cancer can reduce the mortality rate considerably. Affordable and easy to use screening device is essential for mass screening. In this paper, we demonstrate a simple, precise and easy tool for screening and early detection of breast cancer based on the higher temperature of abnormal tissues. We have made excellent reliability chip thermal sensor probes and developed 3D and 2D thermal imaging system that can predict the hot spot precisely by simple surface temperature measurements. The chip thermal sensor probes show less than 0.5% drift in resistance upon thermal and electrical aging. Various phantom experiments were conducted to demonstrate the use of chip thermistor probes for predicting the position of the heater location accurately. We have also found that the subtle changes in surface temperatures were accurately picked up by the thermistors. It is observed that simulated and experimental results were having best fit within root mean square error of 0.055.

ITO:SiC Ceramic Matrix Composite Thermocouples for Engine Components

Surface temperature measurements of ceramic matrix composite (CMC) based engine components within the hot section of a gas turbine engines are needed to verify engine designs and cooling requirements. Traditional temperature sensors cannot be applied to silicon carbide (SiC) based CMC's for this purpose, since they cannot be welded or embedded in the material. For these reasons, a novel thermocouple was developed for surface temperature measurement of p-type SiC-SiC CMC's. This novel thermocouple uses the p-type SiC-SiC CMC itself as one of the thermoelements and indium-tin-oxide (ITO) as the other thermoelement. Since both thermoelements are wide bandgap semiconductors, this thermocouple has exceptional thermoelectric output. A thermoelectric output of 272 μV/°K was observed for this ITO:SiC CMC thermocouple, which is an order of magnitude larger than that of type-K thermocouples. A drift rate of 3.28 °C/h was measured for this ITO:SiC CMC thermocouple. In addition, indium tin oxynitride (ITON) protective coatings deposited via reactive sputtering enabled these thermocouples to operate at 1000 °C. The ITON coating served as an oxygen diffusion barrier to prevent oxidation at the ITO:SiC CMC junction. Nitrogen and air anneals at 550 and 1000 °C, respectively, were used to improve the high temperature stability of the ITO and ITON coatings. Performance, fabrication details, and challenges using these ITO:SiC CMC thermocouple are discussed within.

Sputtered Thermoelectric Nanoparticles for an Ultra-Thin, Flexible and Cuttable Self-Powered Temperature Sensor

Inadequate energy for the growing population has been a major concern in the recent years. Though efforts are being made to alleviate this problem, the crisis still exists. For this reason, the focus of the scientific community is directed towards self-powered technology. As technology is getting smart, smart sensors are also gaining attention. Human beings are getting more and more concerned about their health and opt for the best personalized health care devices. Body temperature is a vital sign which reflects the health condition and thermoregulation in human beings. For continuous monitoring of body temperature, devices which are compact, lightweight and self-powered is therefore desirable. So, we design a highly flexible, ultra-thin and conformable temperature sensor which just uses heat from the body as a power source and senses the body temperature precisely. The sensor works on thermoelectric effect and can detect any surface temperature from room temperature to 100 ˚C and also room temperature to 0 ˚C owing to its conformable and compact design and can be cut into desirable shapes and size. For a temperature gradient of 75 ˚C the sensor gives and output voltage of 0.4 mV and can even detect a human finger touch with an accurate body temperature. Such flexible and thin device can be used in day to day monitoring of human beings enabling it to be used as a wearable temperature sensor, hot or cold surface temperature measurement which may create injury if touched or as a biomedical device for the measurement of hyperthermia or even monitoring the health of pets.

Sputtered Thermoelectric Nanoparticles for an Ultra-Thin, Flexible and Cuttable Self-Powered Temperature Sensor

Inadequate energy for the growing population has been a major concern in the recent years. Though efforts are being made to alleviate this problem, the crisis still exists. For this reason, the focus of the scientific community is directed towards self-powered technology. As technology is getting smart, smart sensors are also gaining attention. Human beings are getting more and more concerned about their health and opt for the best personalized health care devices. Body temperature is a vital sign which reflects the health condition and thermoregulation in human beings. For continuous monitoring of body temperature, devices which are compact, lightweight and self-powered is therefore desirable. So, we design a highly flexible, ultra-thin and conformable temperature sensor which just uses heat from the body as a power source and senses the body temperature precisely. The sensor works on thermoelectric effect and can detect any surface temperature from room temperature to 100 ˚C and also room temperature to 0 ˚C. For a temperature gradient of 75 ˚C the sensor gives and output voltage of 0.4 mV and can even detect a human finger touch with an accurate body temperature. Such flexible and thin device can be used in day to day monitoring of human beings enabling it to be used as a wearable temperature sensor, hot or cold surface temperature measurement which may create injury if touched or as a biomedical device for the measurement of hyperthermia or even monitoring the health of pets.

Probing high temperature thermal emissive properties of energy materials and coatings with emission spectroscopy augmented by in situ reflection

A robust non-contact methodology for the in situ determination of both the temperature and the spectral emissivity of a surface spot is presented. It is applicable to all materials exhibiting an opacity region. Tests performed on different materials demonstrated the high level of accuracy of the method when it is applied to the temperature measurement of smooth surfaces. The accuracy is reduced when probing rough surfaces, but it was shown that the relative uncertainty for temperature was still better than one percent for materials whose roughness characteristic size is less than the wavelength used to perform the temperature determination. Analytical formulas to derive upper limits of the combined standard uncertainties are presented. For rough surfaces, the association with a microfacet model describing the light scattering by the sample surface provides a method to evaluate the optimum spectral range for the determination of the temperature.

Body surface temperature responses to food restriction in wild and captive great tits.

During winter at temperate and high latitudes, the low ambient temperatures, limited food supplies and short foraging periods mean small passerines show behavioural, morphological and physiological adaptations to reduce the risk of facing energy shortages. Peripheral tissues vasoconstrict in low ambient temperatures to reduce heat loss and cold injury. Peripheral vasoconstriction has been observed with food restriction in captivity but has yet to be explored in free-ranging animals. We experimentally food restricted both wild and captive great tits (Parus major) during winter months and measured surface temperatures of the bill and eye region using thermal imaging, to investigate whether birds show rapid local heterothermic responses, which may reduce their thermoregulatory costs when facing a perceived imminent food shortage. Our results of a continuously filmed wild population showed that bill temperature was immediately reduced in response to food restriction compared with when food was available ad libitum, an apparent autonomic response. Such immediacy implies a 'pre-emptive' response before the bird experiences any shortfalls in energy reserves. We also demonstrate temporal variation in vasoconstriction of the bill, with bill temperature gradually rising throughout the food restriction after the initial drop. Eye-region temperature in the wild birds remained at similar levels throughout food restriction compared with unrestricted birds, possibly reflecting the need to maintain steady circulation to the central nervous and visual systems. Our findings provide evidence that birds selectively allow the bill to cool when a predictable food supply is suddenly disrupted, probably as a means of minimising depletion of body reserves for a perceived future shortage in energy.

Comparison of Himawari-8 AHI SST with Shipboard Skin SST Measurements in the Australian Region

Sea surface temperature (SST) measurements from the geostationary satellite Himawari-8 Advanced Himawari Imager (AHI) are compared with in situ skin SSTs derived from shipboard Infrared SST Autonomous Radiometers (ISAR) in the Australian region. The mean bias and standard deviation of the differences between Himawari-8 AHI and ISAR skin SST of best quality are 0.09 K and 0.30 K, with total matchups numbering 2701. Shipboard bulk SST measurements at depths between around 7.1 and 9.9 meters are compared with the matchups in a case study. Analyses show significant differences between skin and bulk SST measurements of maximum value 2.23 K under conditions of high diurnal warming. The results also demonstrate that Himawari-8 AHI skin SST with high temporal resolution has the ability to accurately measure diurnal warming events.

An Evaluation of Autonomous In Situ Temperature Loggers in a Coastal Region of the Eastern Mediterranean Sea for Use in the Validation of Near-Shore Satellite Sea Surface Temperature Measurements

The coastal ocean is one of the most important environments on our planet, home to some of the most bio-diverse and productive ecosystems and providing key input to the livelihood of the majority of human society. It is also a highly dynamic and sensitive environment, particularly susceptible to damage from anthropogenic influences such as pollution and over-exploitation as well as the effects of climate change. These have the added potential to exacerbate other anthropogenic effects and the recent change in sea temperature can be considered as the most pervasive and severe cause of impact in coastal ecosystems worldwide. In addition to open ocean measurements, satellite observations of sea surface temperature (SST) have the potential to provide accurate synoptic coverage of this essential climate variable for the near-shore coastal ocean. However, this potential has not been fully realized, mainly because of a lack of reliable in situ validation data, and the contamination of near-shore measurements by the land. The underwater biotechnological park of Crete (UBPC) has been taking near surface temperature readings autonomously since 2014. Therefore, this study investigated the potential for this infrastructure to be used to validate SST measurements of the near-shore coastal ocean. A comparison between in situ data and Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua and Terra SST data is presented for a four year (2014–2018) in situ time series recorded from the UBPC. For matchups between in situ and satellite SST data, only nighttime in situ extrapolated to the sea surface (SSTskin) data within ±1 h from the satellite’s overpass are selected and averaged. A close correlation between the in situ data and the MODIS SST was found (squared Pearson correlation coefficient-r2 > 0.9689, mean absolute error-Δ < 0.51 both for Aqua and Terra products). Moreover, close correlation was found between the satellite data and their adjacent satellite pixel’s data further from the shore (r2 > 0.9945, Δ < 0.23 for both Aqua and Terra products, daytime and nighttime satellite SST). However, there was also a consistent positive systematic difference in the satellite against satellite mean biases indicating a thermal adjacency effect from the land (e.g., mean bias between daytime Aqua satellite SST from the UBPC cell minus the respective adjacent cell’s data is δ = 0.02). Nevertheless, if improvements are made in the in situ sensors and their calibration and uncertainty evaluation, these initial results indicate that near-shore autonomous coastal underwater temperature arrays, such as the one at UBPC, could in the future provide valuable in situ data for the validation of satellite coastal SST measurements.

Body temperature of horses spending time in paddocks in various weather conditions during the summer

The aim of the study was to determine the internal and surface temperature of selected body parts of horses during their stay in paddocks in various weather conditions in the summer. The study was conducted on 10 adult thoroughbred mares. The experiment was carried out on horses spending time in the paddock in four eight-hour stages with differing weather conditions in summer (sunny, cloudy, rainy and windy). Measurements of internal temperature (Veterinär SC 12 veterinary thermometer) and surface temperature of the head, rib area and croup (Thermal Imagers Ti9 FLUKE infrared camera and SmartView 4.1 software) were carried out at rest and again after four and eight hours in the paddock. It was concluded that the time horses spend in the paddock in summer should depend on weather conditions. Many hours spent outside the stable during sunny weather accompanied by high air temperature can contribute to overheating. On the other hand, rain and wind can cause hypothermia. Therefore, it is worth considering leaving horses in the stable or limiting their stay in the paddock to no more than four hours.

Development of a High-Speed Two-Disc Tribometer for Evaluation of Traction and Scuffing of Lubricated Contacts

This article describes the development of a high-speed, two-disc tribometer to conduct traction and scuffing tests emulating typical aerospace and automotive gear contacts. This tribometer is capable of achieving rolling velocities in excess of 50 m/s at sliding ratios and contact pressures representative of gear tooth contacts at elevated oil supply temperatures. A methodology to remove bearing drag from the traction torque measurements is presented as well as a noncontact surface temperature measurement system to quantify the surface bulk temperatures. Traction curve and scuffing test protocols representative of aerospace and automotive gear contact conditions are devised. Example traction curves and scuffing tests are presented to demonstrate the capabilities of the tribometer.

Utilization of Experimental Data as Boundary Conditions for the Solidification Model Tempsimu-3D

Solidification models are an important tool for the prediction of temperatures and shell growth during the process of continuous casting of steel. To gain reliable simulation results, it is crucial to use highly sophisticated material data and boundary conditions depending on different process parameters. The focus of this work lies on the utilization of experimental data to describe the secondary cooling zone (SCZ) of a slab caster in the solidification model Tempsimu-3D. In this part of the caster, water and air-mist sprays are used to cool down the strand. To calculate the heat transfer coefficient caused by spray cooling (HTCspray), the model uses a correlation between the water impact density (WID) and the surface temperature of the slab. Together with the heat removal due to roll contact and radiation, this HTCspray is applied as a boundary condition for the SCZ. To adjust the parameters of the correlation formula, results from WID and HTC measurements are used. For validation, the simulation results are compared with a measurement of the slab surface temperature.

Marshland Loss Warms Local Land Surface Temperature in China

AbstractChina has the third largest area of marshland in the world. Due to the effects of human activities, marshland in China has been widely converted to built‐up land (BL) and cultivated land (CL) during the past decades. Using satellite measurements of land surface temperature (LST), this study investigated the biophysical effects of marshland loss on LST. The results showed that marshland conversion to BL could increase the LST during both the daytime and nighttime. Conversion from marshland to CL could increase the daytime LST in most months and nighttime LST in the nongrowing season but decrease the daytime LST from July to September and nighttime LST in the growing season. Conversion from marshland to paddy field and dry farmland had different effects on LST. These complex effects suggest that the biophysical effects of marshland conversions should be considered in evaluating the effects of marshland loss on climate change in China.

Thermal imaging of a hydrophobic soil’s response to surfactant application at the Avon River Catchment Critical Zone Observatory

The hydrology of water repellent soil is poorly understood, in part because measuring hydrophobicity often interferes with subsequent water flow. Since soil surface temperatures provide information on near surface water content, thermography offers the potential to indirectly monitor this hydrology non-invasively. Using a near-infrared thermal camera, 15 plots, each 1 m2, of a hydrophobic sandy topsoil were recorded continuously for three weeks in the field. Treatments included plots with surfactant applied in bands from 16 cm to 100 cm width and a control (no surfactant). Soil sampling and continuous monitoring of soil moisture, soil temperature and weather conditions supplemented surface temperature measurements. Surface temperature and surface soil moisture were shown to be negatively correlated during the day and positively at night. Soil moisture probes indicated that water from three 10 mm irrigation events was largely restricted to depths less than 10 cm throughout the experiment. Dynamics of the semi-variance for treated plots were different to that of the control. Empirical orthogonal functionals (EOF) initially showed the dominant variability in spatial pattern reflected the surfactant application. During the course of the experiment, changes in the EOFs revealed the gradual re-emergence of background soil heterogeneity related to prior seeding rows. The monitoring did not reveal any lateral expansion of wetted areas from the edges of surfactant treated strips. Thermography was able to inform the dynamics of soil moisture related to spatial and temporal variability in hydrophobicity under field conditions. The approach offers the potential to non-invasively image dynamic soil hydraulic properties and to evaluate water repellence amelioration methods.

Comparative study of surface temperature of lithium-ion polymer cells at different discharging rates by infrared thermography and thermocouple

The objective of this study was to compare the surface temperature of lithium-ion polymer cells at different discharging rates by infrared thermography and thermocouple measurement. The cells were discharged by using a battery workstation at discharging rates of 2.0 A, 4.0 A, 6.0 A, 8.0 A, and 10.0 A in a controlled testing condition. This study focused on surface temperature distribution, maximum surface temperature, and temperature rise evolution. Higher discharging rate generates more heat in LiPo cells, which causes larger temperature gradient, higher maximum surface temperature, and higher temperature rise. During the discharging process, non-uniformity spatial distribution of LiPo cells was observed. No critical surface temperature was observed when reaching towards the end of discharging process as the surface temperature distribution managed to become spatially uniform. Most of the maximum surface temperatures were spotted at the lower part of the LiPo cells. In addition, the captured infrared (IR) images found that the temperature rises rapidly at higher discharging rates. In comparison, surface temperature measurement by infrared thermography provided higher accuracy than thermocouple. The findings of this study provide evidences in better development of battery thermal management systems with consideration of surface temperature distribution and temperature rise.

Surface temperature measurement of gas turbine combustor using temperature-indicating paint

ABSTRACT Surface temperature measurement of a hot surface is necessary in order to determine its thermal life. The combustors used in gas turbine systems may be subject to high thermal load due to continuous combustion. In order to analyse the surface temperature distribution of combustor, temperature-sensing instruments are necessary. Temperature-indicating paint is a kind of coating to measure the temperature distribution through its colour change. Temperature-indicating paint is considered to be one of the most efficient ways for temperature measurement. The analysis of this paint can be done through the observation of irreversible colour change with temperature. This work deals with the fabrication of gas turbine combustor, investigates the thermal distribution and finds the hot spots of the combustor using temperature-indicating paint.

Ventilation schemes for high-temperature buoyancy-driven plumes from spherical surfaces of a large-scale experimental facility

Abstract A large-scale sphere-shaped experimental facility for neutrino detection is designed as a 23-latitudinal layer composite by using organic glass as the major raw material and is assembled via mass polymerization through a top-to-bottom approach. Heating belts at 4200 W/m2 are used to anneal the bonding joints of external and internal spherical surfaces and produce high-temperature thermal plumes. Buoyancy-driven plumes should be effectively mitigated using ventilation to ensure the near-surface air temperatures above the finished layers can be delicately controlled within 21±1 °C to minimize the deformation of the facility. Schemes to control plumes on both surfaces were investigated using Computational Fluid Dynamics (CFD) method by following a performance-based approach. First, an independent field study was conducted to measure surface temperature and heat flux of mass polymerization and provide references for simulations. Second, dynamic buoyancy-driven plumes produced along the external and internal spherical surfaces were simulated under a no-ventilation scenario. After contacting with the plumes, three periods, in which buoyancy, convection, and advection, were dominating, can be observed according to the changes of near-surface air temperature. Moreover, the temperature and Ra number of the surface-attached plumes were used as indicators to assess the intensity of the plumes quantitatively. Third, three major ventilation schemes, i.e., general, push-pull, and sphere-attached ventilations (with three subdesigns), were compared under the same air change rate level on the basis of the following perspectives: (1) air temperature distributions above the polymerizing layer, (2) overall heat exhaust efficiency, and (3) total spaces where temperature was higher than 22 °C. Results indicated that the combination of push-pull and side-supply ventilations, by which the heat exhaust efficiencies were up to 1.87–3.24, was found to be most effective to control thermal plumes, with approximately 0.1% of the total surrounding air exceeding 22 °C.

Sensitive and fast measurement of surface temperature with a thermogalvanic cell

Thermogalvanic cells may be viewed as electrochemical thermocouples. Here, we demonstrate their potential for sensitive and fast sensing of the surface temperature of a thin Au sheet, in contact with a 0.08 M equimolar ferri-/ferrocyanide solution in 26% KOH. We obtained a sensitivity of about 10 μK, because of the large Peltier coefficient of the electrochemical reaction at the electrode-electrolyte junction. The resolution is limited by the thermal noise of the electrochemical system and could be quantitatively explained by the thermal noise of a Randles equivalent circuit of the cell. Since no thermal contact resistances to bulky temperature sensors are involved, we achieved a response time smaller than 300 μs, which may be potentially lowered to a few microseconds. By using the thermogalvanic cell as a sensor for electrochemical microcalorimetry, we calibrated the system, in full agreement with a simulation of its thermal behavior.

Bayesian Inference for 3D Volumetric Heat Sources Reconstruction from Surfacic IR Imaging

The domain of non-destructive testing (NDT) or thermal characterization is currently often done by using contactless methods based on the use of an IR camera to monitor the transient temperature response of a system or sample warmed by using any heat source. Though many techniques use optical excitation (flash lamps, lasers, etc.), some techniques use volumetric sources such as acoustic or induction waves. In this paper, we propose a new inverse processing method, which allows for the estimation of 3D fields of heat sources from surface temperature measurements. This method should be associated with volumetric heat source generation. To validate the method, a volumetric source was generated by the Joule effect in a homogeneous PVC sample using an electrical thin cylindrical wire molded in the material. The inverse processing allows us to retrieve the depth of the wire and its geometrical shape and size. This tool could be a new procedure for retrieving 3D defects on NDT.

Tree cooling effects and human thermal comfort under contrasting species and sites

The potential of urban greenspaces in regulating temperature is widely known; however, in the heterogeneous urban landscape the process and the magnitude of human thermal comfort as well as the cumulative effects of natural and built surfaces are not yet well understood. We selected two ecologically contrasting species Tilia cordata Mill. and Robinia pseudoacacia L. planted in eight plots across five different sites in Würzburg, one of the major cities in Northern Bavaria, Germany. We monitored meteorological and edaphic variables and tree sap-flow along with the air temperature, relative humidity, within tree canopy and outside, between January 1 and December 31, 2018. Additionally, we measured surface temperature, meteorological variables below the tree canopies and outside, during the hottest summer days of 2018 (July 23 to 31). With 35% higher leaf area index, T. cordata tree canopies prevented higher incoming radiation compared to R. pseudoacacia trees. Moreover, with diffuse porous wood anatomy, T. cordata trees provided four times more transpiration compared to R. pseudoacacia, therefore, up to 2.8 °C air temperature reduction (ΔAT) within the tree canopy, and increase in absolute humidity (ΔAH) up to 2.6 g m − 3 compared to the 1.9 °C of ΔAT and 1.9 g m − 3 of ΔAH for R. pseudoacacia respectively. Thus, physiological equivalent temperature reduction was up to 4 °C under the shade of a R. pseudoacacia tree compared to 11 °C under a T. cordata tree. Finally, the research showed the importance of urban topography, such as street orientation, surrounding environment such as geometry, urban design to reduce the hindrance of wind flow and proportion of greenspaces in terms of outdoor human thermal comfort.