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Measure of temperature dynamics in induction sealing processes is of paramount importance for the validation of physics-based models. In this work, commonly used commercial tools for temperature measurements, such as thermocouples, pyrometers and thermal cameras, are benchmarked for the characterization of the temperature dynamics occurring in multilayer aluminum foil-based packaging material undergoing relatively fast (i.e., ×100 ms) induction heating transients. [ABSTRACT FROM AUTHOR]

This study utilizes Thermal Infrared (TIR) imaging technology to detect hotspots in photovoltaic (PV) modules of solar power plants. Unmanned aerial vehicle (UAV)-based TIR imagery is crucial for efficiently analyzing fault detection in solar power plants. This research explores optimal operational parameters for generating high-quality TIR images using UAV technology. In addition to existing variables such as humidity, emissivity, height, wind speed, irradiance, and ambient temperature, newly considered variables including the angle of incidence between the target object and the thermal infrared camera are analyzed for their impact on TIR images. Based on the solar power plant's tilt (20°) and the location coordinate data of the hotspot modules, the inner and outer products of the vectors were used to obtain the normal vector and angle of incidence of the solar power plant. It was discovered that the difference between measured TIR temperature data and Land Surface Temperature (LST) data varies with changes in the angle of incidence. The analysis presented in this study was conducted using multiple regression analysis to explore the relationships between dependent and independent variables. The Ordinary Least Squares (OLS) regression model employed was able to explain 63.6% of the variability in the dependent variable. Further, the use of the Condition Number (Cond. No.) and the Variance Inflation Factor (VIF) revealed that the multicollinearity among all variables was below 10, ensuring that the independence among variables was well-preserved while maintaining statistically significant correlations. Furthermore, a positive correlation was observed with the actual measured temperature values, while a negative correlation was observed between the TIR image data values and the angle of incidence. Moreover, it was found that an angle of incidence between 15° and 20° yields the closest similarity to LST temperature data. In conclusion, our research emphasizes the importance of adjusting the angle of incidence to 15–20° to enhance the accuracy of TIR imaging by mitigating overestimated TIR temperature values. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to compare rectal temperature (RT) with temperatures measured in the pinna, cornea, medial canthus, gingiva, metacarpal pad and axillary region of cats in a home environment. Animals Studied: Five healthy mixed‐breed cats (two females and three males) owned by a veterinarian were used. Procedures: All temperature measurements were conducted by the owner by using an infrared camera in the same room and initiated with the pinna, followed by the cornea, medial canthus, gingiva and metacarpal pad. Subsequently, axillary temperature (AT) and RT were recorded by a digital thermometer, respectively. The time taken for a single AT and RT measurements was recorded. Results: The average measurement time for RT was 17.34 ± 0.89 s, with a range of 8–32 s, whereas AT measurements took an average of 46.72 ± 1.16 s, with a range of 29–69 s. AT emerged as a superior alternative measurement site compared to others, exhibiting the lowest bias and the highest proportion of readings within the limits of clinical agreement. The mean difference between RT and AT, with 95% limits of agreement for the differences, was −0.26 (−1.13 to 0.61). Conclusions: Anatomical regions were not all interchangeable with the rectum for assessing body temperature (BT), with AT recording the highest level of agreement with RT. When RT is not possible, AT could be considered as an alternative for monitoring BT in clinically healthy cats that live in a home environment. [ABSTRACT FROM AUTHOR]

The key feature of non-contact temperature measurement provided by infrared (IR) cameras underpins their versatility. However, the accuracy of temperature measurements with IR cameras depends on imaging quality due to their non-contact nature, such as the lens, body temperature, and measurement environment. This paper addresses the correction of radial distortion and nonlinear response issues in IR cameras. To address radial distortion, we have designed a passive checkerboard calibration board specifically for infrared cameras. This board is used to calibrate the IR camera and derive the necessary camera parameters. Subsequently, these parameters are applied during the actual measurement process to rectify radial distortion effectively. Building on the radial distortion correction method mentioned above, we propose a multi-point segmented calibration approach that considers different temperature ranges and imaging regions. This method alleviates the issue of reduced temperature measurement accuracy due to variations in camera responses by computing gain and offset coefficient matrices for each temperature range. Experimental results demonstrate the effectiveness of the calibration board in correcting radial distortion in IR cameras, with a mean reprojection error of less than 0.16 pixels. Regarding the nonlinear response problem, the introduced method significantly reduces the relative error in temperature measurement. In the verification phase, spanning from 100 to 500 °C, the average relative error in temperature measurement decreases by 0.49% from 1.61% before and after correction, which highlights a substantial improvement in temperature measurement accuracy. This work gives a useful reference to improve the imaging quality and temperature measurement accuracy using infrared cameras. [ABSTRACT FROM AUTHOR]

In the thermography process, accurately determining emissivity is crucial to obtain precise temperature measurements as it enables the conversion of radiometric values to absolute temperatures. However, assessing emissivity is not a straightforward task as it depends on various other parameters. Traditional methods for measuring emissivity often involve costly materials and cannot be carried out simultaneously with infrared image acquisition. This article presents a method for obtaining pixel-wise emissivity using data from a multispectral infrared camera. Consequently, this method allows for direct emissivity measurement during infrared camera acquisition without the need for additional materials or experiments. [ABSTRACT FROM AUTHOR]

During an epidemic, accurate human temperature screening based on neural networks for disease surveillance is important and challenging. Existing distant human forehead temperature measuring device usually adopts a dual-camera system using paired RGB and thermal infrared images to conduct face detection and temperature measurement. Since the facial RGB image may undermine people's privacy, we designed a monocular thermal system and proposed an effective framework called the InfraNet to measure and calibrate forehead temperature of people in the wild. To address the challenge of temperature floating, the InfraNet calibrates the subject's temperature with one's physical depth and horizontal offset predicted by a single infrared image. Our InfraNet framework mainly consists of three parts: face detection subnet, depth and horizontal offset estimation subnet and temperature calibration subnet. The temperature calibration performance can be improved with the help of spatial regularization term concentrating on predicting precise depth and horizontal offset of people. Besides, we collected a large-scale infrared image dataset in the both lab and wild scenarios, including 8,215 thermal infrared images. Experiments on our wild dataset demonstrated that the InfraNet achieved 91.6% high accuracy of distant multi-subject temperature measurement on average under the standard temperature threshold of strict 0.3°C. [ABSTRACT FROM AUTHOR]

The measurement of product temperature is one of the methods that can be adopted, especially in the pharmaceutical industry, to monitor the freeze-drying process and to obtain the values of the process parameters required by mathematical models useful for in-line (or off-line) optimization. Either a contact or a contactless device and a simple algorithm based on a mathematical model of the process can be employed to obtain a PAT tool. This work deeply investigated the use of direct temperature measurement for process monitoring to determine not only the product temperature, but also the end of primary drying and the process parameters (heat and mass transfer coefficients), as well as evaluating the degree of uncertainty of the obtained results. Experiments were carried out with thin thermocouples in a lab-scale freeze-dryer using two different model products, sucrose and PVP solutions; they are representative of two types of commonly freeze-dried products, namely those whose structures are strongly nonuniform in the axial direction, showing a variable pore size with the cake depth and a crust (leading to a strongly nonlinear cake resistance), as well as those whose structures are uniform, with an open structure and, consequently, a cake resistance varying linearly with thickness. The results confirm that the model parameters in both cases can be estimated with an uncertainty that is in agreement with that obtained with other more invasive and expensive sensors. Finally, the strengths and weaknesses of the proposed approach coupled with the use of thermocouples was discussed, comparing with a case using a contactless device (infrared camera). [ABSTRACT FROM AUTHOR]

During machining processes, a high temperature is generated in the cutting zone due to deformation of the material and friction of the chip along the surface of the tool. This high temperature has a detrimental effect on the cutting tool, and for this reason, it is of the utmost importance to assess the cutting temperature in real time during these processes. Despite all the advances and investigation in this field, accurately measuring the cutting temperature remains a great challenge. In this sense, this work intends to contribute to solving this problem by experimentally evaluating the potential of the developed approach for embedding thermocouples into the rake face of cutting tools for measuring cutting temperature in real time during dry turning of AISI 1045 steel for different cutting parameters and comparing the obtained results with infrared thermography measurements at the exact same point. A well-defined, smooth micro-groove with good surface quality was produced by laser surface modification. Then a laser-welded K-type thermocouple was fixated in the micro-groove with a MgO ceramic adhesive, ensuring protection from wear and chips, which allowed the creation of WC-Co cutting inserts with the ability to measure cutting tool temperature with a maximum error of 0.96%. Results showed that, despite yielding the same trend, the tool temperature measured by the IR thermographic camera was always lower than the temperature measured by the K-type embedded thermocouple. The proposed embedded thermocouple method proved to be a reliable, precise, accurate, and cost-effective approach for real-time temperature measurement capable of providing useful information for cutting parameter optimization, thus allowing increased productivity and tool life. [ABSTRACT FROM AUTHOR]

The deformation of metallic materials during the machining operation requires a significant amount of energy. During the chip formation process and due to the plastic deformation of the metal and the friction along the tool-part interface, the thermal loads generated are strongly impacted by the cutting factors. Thus, the choice of optimized cutting conditions is essential to control the quality of the work required. The aim of the present experimental study is to optimize the cutting parameters using temperature measurements. The average temperature of the cutting tool is studied using a FLIR A325sc type infrared camera. Optimal cutting parameters for each performance metric were obtained using the Taguchi techniques. [ABSTRACT FROM AUTHOR]

The experiments conducted in a didactic laboratory of the Kielce University of Technology involved temperature distribution measurements on the outer surface of a steel radiator using a thermal imaging camera and thermocouples to compare both investigation methods. The research included registering the parameters for a specific period for each of the four different medium flows. Graphs present the results with the division of the radiator into eight thermal fields. The results present the differences in temperatures between 1.78°C to 3.65°C. The non-contact method with an infrared camera seems more accurate since it is precise for surface temperature measurement. [ABSTRACT FROM AUTHOR]

Gas remote detection is useful for early warning of gas leakage and toxic chemicals. Optical gas imaging (OGI) built with an uncooled infrared camera is superior to cooled detectors in terms of cost. Current mainstream OGI technologies fall short in their detection of gases at ambient temperature and their ability to classify multiple gases. A multi-spectral uncooled imager is developed to try to solve these problems, which is constructed from a commercial uncooled thermal camera and wide band filters. To solve filter self-radiation and unevenness, a correction method is devised, with an ambient temperature blackbody placed in front and subtracted from the measured image. Based on waveband cutoffs, filters are classified into target-sensitive filters and background filters. Multi-spectra are simulated according to wide band filter transmittance, which can be used in gas classification. A sulfur hexafluoride (SF6) experiment is conducted outdoors at a distance of 10 m. An SVM model is trained to classify gas release in real time. Detection with a cold sky background is improved with the aid of data cube differences in a time sequence. The SF6 outdoor experiment concluded with preliminary effective results of ambient temperature gas remote detection. [ABSTRACT FROM AUTHOR]

Tungsten is regarded as the baseline first wall material in tokamaks. This work provides a polarized method for measuring the emissivity and temperature of the tungsten using an infrared camera and a polarizer under simulating tokamak conditions. In the experiment, a polarizer with an adjustable polarization direction is set up in front of an infrared camera. A rotatable fixture is used to fix the sample and change the angle between the surface and the normal. The sample is rotated from 0° to 80°, and the polarized emissivity first increases and then decreases with increasing rotation angle. The uncertainty in emissivity resulting from this polarized method and non-polarized method is analyzed. To compare the effects of the polarized method and the non-polarized method, the rotation angle is adjusted to 0°, and a fitting model is used to describe the relationship between emissivity and temperature. Errors between the calculated temperature and measured temperature are used as a scale, and the polarized method improves the accuracy of temperature measurement. This polarized method provides a technical way to measure the emissivity and temperature in a tokamak and can be applied in other similar applications. [ABSTRACT FROM AUTHOR]

Unlike other thermal spraying methods, it is difficult to determine the temperature of the particles during cold gas spraying due to the relatively low radiation. In the present study, the velocities and in-flight temperatures of metal particles were measured during cold gas spraying. A state-of-the-art high-speed infrared camera was used to study the behavior of two different base materials, In718 and TiAlCrNb, both used as structural materials in gas turbine engines. The experiments aimed to improve the fundamental understanding of the process, in particular the heating of the particles, and to compare the experimental results with theoretical calculations of the particle temperatures. [ABSTRACT FROM AUTHOR]

Thermographic particle tracking velocimetry (PTV) using phosphor particles with temperature sensing function as tracer particles has attracted attention due to its temperature and velocity simultaneous sensing function. However, due to the influence of particle movement on temperature measurement, the current mainstream thermographic PTV mainly uses the intensity ratio method, while the lifetime-based method with higher accuracy and simpler experimental configuration are limited. In this study, we introduce an adaptive windows technique for lifetime-based two-dimensional thermographic PTV. Adaptive windows are applied according to the calculated velocity to eliminate the limitation of lifetime-based temperature measurement due to particle movement. Through the adaptive windows, the phosphorescence signals are confined in local windows during the entire decay process, and high-accuracy temperature information can be obtained. The technique is then demonstrated in a forced convection flow. The results show that the current technique could be available in water with a temperature range of 18.5–82.34 °C and a velocity range of 0–0.033 m/s, and the temperature measurement accuracy can be kept within 11 °C. It has overcome the influence of particle movement on lifetime-based phosphorescent PTV, which could provide high-accuracy temperature and velocity simultaneous measurement with a single camera. [ABSTRACT FROM AUTHOR]

The Thermal Infrared Sensor 2 (TIRS-2) on Landsat 9 (L9) was launched on September 27, 2021, and underwent a variety of tests during its commissioning phase to establish its postlaunch performance. We report on the calibration updates performed to maintain its calibration and generate high-quality imagery. This is done by transferring the SI-traceable prelaunch calibration to on-orbit while accounting for changes in the TIRS-2 response as detected through on-board calibrator observations. Additional empirical corrections were implemented to mitigate image striping observed on-orbit. The detector arrays were monitored through its commissioning phase to ensure that stable detectors were chosen for operations. TIRS-2 has demonstrated ~0.025% instability over its orbit, ~80-mK noise equivalent delta temperature (NEdT), and an absolute radiometric uncertainty <1.4% in its nominal temperature range enabling a wide array of Earth science applications. [ABSTRACT FROM AUTHOR]

The paper presents the methodology and results of experimental works concerning temperature of burnishing process. The research was carried out during disk burnishing of external cylindrical surfaces on a universal lathe CDS 6250 BX-1000 with severe parameters. As workpiece material steel S235JR has been selected. For temperature measurements infrared thermography method was chosen. This technique has a lot of advantages, the main is that it is non-contact technique and therefore there is no disturbance of the temperature field. In presented research infrared camera E95 produced by FLIR® Systems Inc. was used. Test results indicates the slight influence of process parameters on burnishing temperature. [ABSTRACT FROM AUTHOR]

Simultaneous measurement of the temperature in different regions during machining operations presents many limitations. Currently, only orthogonal cutting using a infrared camera allows the simultaneous measurement of temperature in different regions. Additionally, temperature measurement in certain regions is a challenge, for instance, in the chip/tool interface and inside the chip. The application of advanced sensors and the adaptation of well-established techniques in regions of difficult access, such as the chip-tool interface and the chip itself, have been the subject of research to allow the better understanding of the heat generation and temperature evolution during machining operations. This work investigates the application of the inserted thermocouple method to measure the temperature inside the chip during its formation, together with the tool-workpiece thermocouple method to compare the effect of the cutting parameters on both the chip-tool interface and chip temperature. Orthogonal cutting of AISI 1020 steel was performed using cemented tungsten carbide bits. The findings indicated that both methods were able to assess the influence of the investigated parameters and that temperature presented the same behavior, in spite of the differences in absolute values (higher temperatures were recorded using the tool-workpiece thermocouple). Temperature increased with cutting speed, decreased with the elevation of the undeformed chip thickness and was not affected by width of cut. The highest temperature (668 °C) was observed at the tool-workpiece interface using a cutting speed of 120 m/min, undeformed chip thickness of 0.1 mm and width of cut of 1.5 mm. [ABSTRACT FROM AUTHOR]

Knowledge of material emissivity maps and their true temperatures is of great interest for contactless process monitoring and control with infrared cameras when strong heat transfer and temperature change are involved. This approach is always followed by emissivity or reflections issues. In this work, we describe the development of a contactless infrared imaging technique based on the pyro-reflectometry approach and a specular model of the material reflection in order to overcome emissivities and reflections problems. This approach enables in situ and real-time identification of emissivity fields and autocalibration of the radiative intensity leaving the sample by using a black body equivalent ratio. This is done to obtain the absolute temperature field of any specular material using the infrared wavelength. The presented set up works for both camera and pyrometer regardless of the spectral range. The proposed method is evaluated at room temperature with several heterogeneous samples covering a large range of emissivity values. From these emissivity fields, raw and heterogeneous measured radiative fluxes are transformed into complete absolute temperature fields. [ABSTRACT FROM AUTHOR]

Limitations of microwave processing due to inhomogeneities of power input and energy absorption have been widely described. Over‐ and underheated product areas influence reproducibility, product quality, and possibly safety. Although a broad range of methods is available for temperature measurement and evaluation of time/temperature effects, none of them is sufficiently able to detect temperature differences and thermally induced effects within the product caused by inhomogeneous heating. The purpose of this review is to critically assess different methods of temperature measurement for their suitability for different microwave applications, namely metallic temperature sensors, thermal imaging, pyrometer measurement, fiber optic sensors, microwave radiometry, magnetic resonance imaging, liquid crystal thermography, thermal paper, and biological and chemical time‐temperature indicators. These methods are evaluated according to their advantages and limitations, method characteristics, and potential interference with the electric field. Special attention is given to spatial resolution, accuracy, handling, and purpose of measurement, that is, development work or online production control. Differences of methods and examples of practical application and failure in microwave‐assisted food processing are discussed with a special focus on microwave pasteurization and microwave‐assisted drying. Based on this assessment, it is suggested that infrared cameras for measuring temperature distribution at the product surface and partially inside the product in combination with a chemical time/temperature indicator (e.g., Maillard reaction, generating heat‐induced color variations, depending on local energy absorption) appear to be the most appropriate system for future practical application in microwave food process control, microwave system development, and product design. Reliable detection of inhomogeneous heating is a prerequisite to counteracte inhomogeneity by a targeted adjustment of process and product parameters in microwave applications. [ABSTRACT FROM AUTHOR]

Temperature is one of the most common indicators for the health of electrical equipment in the substation. By now, infrared thermography has been an important monitoring tool due to its real‐time temperature measurement and noncontact manner. However, at present, portable thermal imagers are usually used to collect and store the status image of single equipment at a certain time, which cannot continuously track the condition of the equipment and the efficiency is very low. In order to solve this problem, our team proposed a method for online condition of electrical equipment based on the visualization and processing of infrared image temperature data. We developed video inspection software, equipped with an infrared camera for automatic inspection to obtain infrared images. After that, the target equipment in a whole image are automatically extracted based on the reference image and the equipment type of each target is classified. Then, in order to visualize temperature data and extract temperature information for different types of equipment, the concepts of heating spot, heating section, and heating area are defined. Finally, diagnosis rules based on relevant related thermal fault diagnosis standards and past experience are proposed to evaluate the condition of each target equipment, using the temperature rise and heat generation percentage. The method has been applied in a real substation and proved its effectiveness. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

• A novel framework for PV module defects based on the combination of visible and infrared images is proposed. • The proposed framework employs both YOLOv5 and ResNet algorithms to conduct image segmentation and fault detection respectively. • The framework suits almost all brightness conditions with strong applicability and high accuracy. Solar Photovoltaic (PV) industry has achieved rapid development in recent years. However, it is difficult and costly to detect the micro fault area in a large PV power plant due to environmental factors and missing data. Most faults can be detected by the infrared temperature measurement method, but the infrared camera characteristics constrain it. This paper proposed a novel framework, consisting of image acquirement, image segmentation, fault orientation and defect warning, to remedy the limitations for PV module defects. The visible and infrared PV array images are taken under the same conditions by a dual infrared camera at low altitudes. The deep learning methods, including the fifth version of You Only Look Once (YOLOv5) algorithm and Deep Residual Network (ResNet) algorithm, are introduced to this framework. Hence, this framework has strong capability to suit almost all brightness conditions, by the combination of image segmentation from visible images and fault location on infrared images. The results show that this framework dramatically improves the separation speed of photovoltaic array to 36 Fps and the accuracy of fault detection to 95% by infrared image marked with the segmented area. [ABSTRACT FROM AUTHOR]

In this work, the transient responses of a heated infrared (IR) temperature sensor were investigated to improve the reliability of determined target temperatures obtained from IR-based medical thermometers. A medical-grade IR temperature sensor was heated at the lower edge of the sidewall of the sensor. To reduce the uncertainty due to the conversion factor of the thermal detector, the temperature of the target, which was a thermostatted blackbody source, was determined when the observed target temperature and the temperature of the detector coincided during the heating and cooling of the sensor. When the determined target temperature was compared with the blackbody source temperature, it was found that during heating, due to the produced temperature gradient in the sensor, the observed target temperature showed erroneous depressions, resulting in the determined target temperature being considerably lower than the true target temperature. In contrast, the determined target temperature during cooling of the heated sensor was consistent with the tested blackbody source temperatures within the claimed uncertainty at all heating conditions. Therefore, based on the obtained results, it was concluded that temperature measurements using an IR temperature sensor could be carried out with the least uncertainty by determining the target temperature when the observed target and detector temperatures coincided during cooling of the heated sensor. [ABSTRACT FROM AUTHOR]

This work reports a method to measure thermal diffusivity of thin disk samples at high temperatures (approximately 900-1150 K) using a modified Ångström's method. Conventionally, samples are heated indirectly from the surroundings to reach high temperatures for such measurements, and this process is time-consuming, typically requiring hours to reach stable temperatures. In this work, samples are heated directly in a custom instrument by a concentrated light source and are able to reach high steady-periodic temperatures in approximately 10 min, thus enabling rapid thermal diffusivity characterization. Further, existing Ångström's methods for high temperature characterization use thermocouples for temperature detection that are commonly attached to samples via drilling and welding, which are destructive to samples and introduce thermal anomalies. We use an infrared camera calibrated to 2000 °C for noncontact, nondestructive, and data-rich temperature measurements and present an image analysis approach to process the infrared (IR) data that significantly reduces random noise in temperature measurements. We extract amplitude and phase from processed temperature profiles and demonstrate that these metrics are insensitive to uncertainty in emissivity. Previous studies commonly use regression approaches for parameter estimation that are ill-posed (i.e., nonunique solutions) and lack rigorous characterization of parameter uncertainties. Here, we employ a surrogate-accelerated Bayesian framework and a "no-U-turn" sampler for uncertainty quantification. The reported results are validated using graphite and copper disks and exhibit excellent agreement within 5% as compared to reference values obtained by other methods. [ABSTRACT FROM AUTHOR]

Body temperature is an important indicator that may indicate the possibility of the existence of various pathological conditions and diseases. In the head and neck area, an infrared camera allows accurate temperature measurements of all regions of interest. The analysis of temperature characteristics of the region of interest of the head and neck in healthy subjects in terms of comparison of values in relation to the side of the face in the same person, and the comparison of values relative to the sex of the subjects is the topic of this research. These analyses are performed to create temperature maps of the face and determine physiological values. The research was conducted with the participation of 30 healthy people, 16 women and 14 men of different ages. Thermal imaging was performed in controlled conditions with infrared thermographic camera Varioscan 3021ST, while the software package IRBIS Professional 2.2 was used for thermogram analysis. Results show that the temperatures in female subjects at the submandibular region are significantly lower than in male subjects with an average temperature difference of 0.46°C, and the temperatures in female subjects at the supraorbital region are on average 0.5°C higher than in male subjects. [ABSTRACT FROM AUTHOR]

The thermographic temperature measurement is burdened with uncertainty. This non-contact temperature measurement method makes it possible to measure the temperature of the electrical device under load. When the observed object is small (a few square millimeters) the spatial resolution of the thermographic cameras is often insufficient. In this case, the use of the additional macro lens is needed. After using an additional lens, the uncertainty of the thermographic measurement is different from the uncertainty of thermographic measurement without an additional lens. The values of the uncertainty contributions depend on the conditions during the measurement and the used methodology. The authors constructed an uncertainty budget of thermographic temperature measurement with an additional macro lens, based on EA-4/02 (European Accreditation publications). The uncertainty contributions were also calculated. On the basis of the calculated values of the uncertainty contributions, it was determined which factor had the greatest impact on the value of the thermographic temperature measurement with an additional lens. [ABSTRACT FROM AUTHOR]

Extending the shelf-life and ensuring microbiological safety of food products while preserving the nutritional properties are key aspects that must be addressed. Heat processing of food matrices has been the golden standard during the last decades, while certain non-thermal processing options have recently gained ground. In the present study, experimental pulsed light (PL) surface inactivation treatments of Salmonella enteritidis on almonds kernels are performed. The PL system is set to test different operative conditions, namely power (1000, 1250, and 1500 W) and frequency (1.8, 3.0, and 100.0 Hz) at different treatment times (from 5 to 250 s), which result in applied fluence doses in the 0–100 J·cm−2 range. Additionally, temperature measurements are collected at each operative condition on the almond surface (using infrared (IR) thermography) and at the superficial layer of the almond (1-mm depth using a thermocouple). The observed PL inactivation kinetics are then modelled using four different models. The best goodness-of-fit is found for the two-parameter Weibull model (R2 > 0.98 and RMSE < 0.33 for all cases). The maximum achieved log-CFU reductions are 6.02 for the 1.8-Hz system, 4.69 for the 3.0-Hz system, and 3.66 for 100.0-Hz system. The offset between the collected temperature readings by the two sensors is contrasted against the inactivation rate (following the two-parameter Weibull model). It was found that the highest inactivation rate corresponds approximately to the point where the infrared camera detects a slowdown in the surface heating. [ABSTRACT FROM AUTHOR]

Abstract-In this study, an experimental measurement methodology is implemented that allows obtaining consistent temperature data during the turning operation of semi-hard C20 steel using SNMG carbide insert, allowing us to have better control at the tool-part interface. The interactions of the phenomena influencing the cut led our choices on the development of a correlation model for the analysis and prediction of the relationships between the machining parameters by measurement of the temperature. The measurement procedure implemented for the temperature estimate is based on the use of an FLIR A325sc type infrared camera mounted and protected by a device on the machine tool. The Taguchi method was chosen to find the relationships between the input factors (cutting speed (Vc), feed rate (a), depth of cut (p)), and the output factor (temperature (T)). In the future, we will develop a numerical validation model to simulate the machining process in order to predict temperatures. [ABSTRACT FROM AUTHOR]

With the establishment and large-scale use of fifth-generation (5G) wireless networks, it is foreseeable that the Cellular Internet of Things (CIoT) will be applied in various fields. For instance, there are a large number of sensors for temperature measurement and cameras for video capture in cities. To provide highly reliable CIoT services, a reliable communication network must be designed. One of the commonly used methods to design a reliable communication network in a distributed system is to reach a consensus. However, none of the protocols proposed for the consensus problem in the past can be directly used in the network topology of CIoT. We propose an optimal protocol, the reliable communication medium consensus (RCMC), to reach a consensus on CIoT. The maximum number of abnormal communication media (CMs) in the CIoT topology is tolerated by the proposed RCMC, and only two data exchanges need to be performed. [ABSTRACT FROM AUTHOR]

Online junction temperature (Tj) measurement enables robust power converter operations by providing overtemperature protection and condition monitoring of the power devices. For SiC MOSFETs, the real-time (Tj) information is especially critical as limited field data are available regarding the reliability. In this article, utilizing the turn-on delay time as temperature sensitive electrical parameter, an online (Tj) measurement is realized through an intelligent gate drive. Specifically, the turn-on delay time is translated into the pulsewidth of a digital signal through the conditioning/logic circuits. During (Tj) measurements, the adjustable gate resistance circuit is activated to improve the measurement sensitivity beyond 600 ps/°C. Using the high-resolution capture module (300-ps resolution) in the system microcontroller, this pulsewidth is measured and then converted to junction temperature with a resolution of <0.5 °C. A prototype is built to validate the online (Tj) measurement method. The switching test results show that the circuit is able to precisely measure Td,on and offers a good linearity/sensitivity for (Tj) estimation. In the continuous operation, the junction temperature of a decapsulated device using an infrared camera and (Tj) obtained from the circuit match well with <1 °C difference under various operating conditions. In addition, the gate-oxide degradation's impact on Td,on is considered for SiC MOSFETs, and an aging compensation scheme is discussed to maintain the measurement accuracy throughout the device's lifetime. It is shown that the proposed circuit provides an accurate real-time (Tj) measurement for SiC MOSFETs, which can be deployed to improve the power converters’ reliability. [ABSTRACT FROM AUTHOR]

Noninvasive thermometry during magnetic nanoparticle hyperthermia (MNH) remains a challenge. Our pilot study proposes a methodology to determine the noninvasive intratumoral thermal dose during MNH in the subcutaneous tumor model. Two groups of Ehrlich bearing-mice with solid and subcutaneous carcinoma, a control group (n = 6), and a MNH treated group (n = 4) were investigated. Histopathology was used to evaluate the percentage of non-viable lesions in the tumor. MNH was performed at 301 kHz and 17.5 kA.m−1, using a multifunctional nanocarrier. Surface temperature measurements were obtained using an infrared camera, where an ROI with 750 pixels was used for comparison with computer simulations. Realistic simulations of the bioheat equation were obtained by combining histopathology intratumoral lesion information and surface temperature agreement of at least 50% of the pixel's temperature data calculated and measured at the surface. One animal of the MNH group showed tumor recurrence, while two others showed complete tumor remission (monitored for 585 days). Sensitivity analysis of the simulation parameters indicated low tumor blood perfusion. Numerical simulations indicated, for the animals with complete remission, an irreversible tissue injury of 91 ± 5% and 100%, while the one with recurrence had a lower value, 56 ± 7%. The computer simulations also revealed the in vivo heat efficiency of the nanocarrier. A new methodology for determining noninvasively the three-dimensional intratumoral thermal dose during MNH was developed. The method demonstrates the potential for predicting the long-term preclinical outcome of animals treated with MNH. [ABSTRACT FROM AUTHOR]

Summary: This paper deals with the identification of the thermal parameters of multilayer objects using the concept of thermal impedance. In order to perform such identification, temperature evolution in time is obtained by an infrared camera after power excitation is applied in the investigated structure. Infrared thermography offers the advantage of being a noncontact temperature detection and measurement method. In many practical cases, it is impossible to use contact temperature measurements. Typically, the power in the form of a step function is applied. In order to calculate the thermal impedance of an object, temperature and power are converted into the frequency domain using the Laplace transform for s = jω. Then, the poles of the thermal impedance are identified using vector fitting, which allows calculating the thermal impedance as a sum of partial fractions. This corresponds directly to the Foster network of a thermal object. In addition, the vector fitting method offers much better convergence in comparison with other methods using the polynomial rational approximation of thermal impedance. A considerable improvement of the numerical Laplace transform in high frequency range is proposed. In this approach, the variable s = jω is replaced by s~=α+jω, and then, the integration result is corrected by the Taylor series. It leads to a kind of filtering of the temperature signal. [ABSTRACT FROM AUTHOR]

Summary: Considering that the anode and cathode in batteries have different heat generation behaviors and that there is almost no technique for measuring the heat generation of the anode and cathode under nondestructive conditions, we proposed a novel in‐situ nondestructive temperature measurement technique for acquiring the heat generated by the anode and cathode. To this end, a Swagelok Li‐ion battery cell is designed to visualize the temperature of the anode and cathode by using an infrared camera. Compared with the anode's heat generation, the cathode generates more heat at a 0.5 C current. The reversible heat generation of the electrode has an exothermic effect, which could be transformed into an endothermic effect within 0% to 100% depth of discharge (DoD). The irreversible heat generation always has an exothermic effect and decreases during the delithiation process. Therefore, it can be concluded that it is likely that variations in the heat generated by the anode and cathode can be measured by using the proposed nondestructive method. Finally, it is meaningful that the effects of the anode/cathode chemistry and other factors such as C‐rate and temperature on the local heat generation will be investigated in future works. [ABSTRACT FROM AUTHOR]

The effect of impingement cooling using a dual synthetic jet actuator (SJA) with improvement of exit configuration has been investigated experimentally. A hump with cross section of a half-elliptic shape was attached to the flat between the two exits of the SJA. Due to Coanda effect, spread of the synthetic jet was enhanced. Two different humps with height to half width ratios of e = 1.0 and 1.5 have been tested. An infrared camera was utilised to record the temperature of the cooled plate. Statistical results of the temperature have been discussed. With humps, average temperature of the impinged area decreased about 2.6 °C and 0.6 °C corresponding to e = 1.0 and 1.5. Standard deviation of the temperature in the impinged area was almost unchanged. Effective cooled area on the plate was enlarged significantly. For e = 1.0 and 1.5, the effective cooled area with temperature below 20 °C increased by 1.1 and 0.5 times. It means that the improvement is very helpful to applications of electrothermal cooling that involve large cooled area. [ABSTRACT FROM AUTHOR]

Copyright of Thermology International is the property of European Association of Thermology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aimed to determine the temperature increase on the root surface during warm vertical compaction using three different obturation systems. Forty-five human single-rooted premolars were randomly assigned to one of three experimental groups of 15 teeth each for obturation with a System B unit, an Elements Obturation Unit, or a B&L SuperEndo Alpha II unit. All teeth were filled using the continuous wave of condensation technique with a set temperature of 200 °C. The temperature measurements were made with an infrared camera at 3 s (T0) and 1 min (T1) following activation of the heat plugger. T0 ranged between 48.1 and 84 °C depending on the obturation system. The mean value for T0 showed significant differences between various obturation systems (p = 0.001). The temperature increase on the root surface during the application of vertical compaction shows considerable variability depending on the obturation system. [ABSTRACT FROM AUTHOR]

We present the metrological characterization and calibration of three different types of thermographic cameras for quantitative temperature measurement traceable to the International Temperature Scale (ITS-90). Relevant technical specifications – i.e., the non-uniformity of the pixel-to-pixel responsivity, the inhomogeneity equivalent temperature difference (IETD), the noise equivalent temperature difference (NETD), and the size-of-source effect (SSE) – are determined according to the requirements given in the series of Technical Directives VDI/VDE 5585. The measurements are performed with the camera calibration facility of the Physikalisch-Technische Bundesanstalt. The data reference method is applied for the determination and improvement of the non-uniformity, leading to an improved IETD for all three cameras. Finally, the cameras are calibrated according to the different procedures discussed in the VDI/VDE 5585 series. Results achieved with the different calibration procedures are compared for each type of camera and among the three cameras. An uncertainty budget for the calibration of each camera is given according to GUM (ISO, 1995) and VDI/VDE 5585. [ABSTRACT FROM AUTHOR]

Background. In orthodontics, erbium (Er:YAG) lasers can be used for bracket debonding. Objectives. To assess the changes in temperature of pulp and enamel during laser debonding of brackets. Material and methods. A total of 13 brackets (n = 13; 2 metal and 11 ceramic brackets) were bonded to 13 caries-free premolars extracted for orthodontic reasons. Brackets were irradiated with 2 lasers. Laser No. 1 was an erbium-chromium (Er,Cr:YSGG) laser (Waterlase Express; Biolase, Irvine, USA) with a wavelength of 2,780 nm at a power of 2.78-2.85 W, energy of 185-190 mJ, fluence of 10 ns, frequency of 25 Hz, pulse duration of 300 µs, tip diameter of 0.6 mm, air/fluid cooling of 3.5 mL/s, and time of irradiation of 5-25 s. Laser No. 2 was an Er:YAG laser (LiteTouch; Light Instruments Ltd., Yokneam, Israel) with a wavelength of 2,940 nm at a power of 4 W, energy of 200 mJ, fluence of 10 ns, frequency of 20 Hz, pulse duration of 300 µs, tip diameter of 0.8 mm, air/fluid cooling of 3.5 mL/s, and time of irradiation of 5--15 s. Two thermographic cameras (FLIR Zenmuse XT and FLIR P65; FLIR Systems, Wilsonville, USA) and type K thermocouple (Zhangzhou Weihua Electronic Co., Fujian, China) were used for precise temperature measurement on the surface of the teeth and inside them. Results. When laser No. 1 was in use, the mean difference between the inner and outer temperature of the examined teeth (1.4°C) was higher than when the laser No. 2 was in use (0.6°C) (p = 0.0974). The study found that the temperature inside the tooth did not increase, and it even decreased during treatment with Er:YAG laser using water cooling, provided that appropriate proportion of water and air was used. For laser No. 1, confidence interval (CI) was between 0.7 and 2.2 and for laser No. 2 it was between 0.500 and 1.23. Only experiment for ceramic brackets was described. Conclusions. These findings confirm that the use of Er:YAG family lasers for orthodontic bracket debonding in an in vitro study is safe and effective. [ABSTRACT FROM AUTHOR]

Infrared thermometry is a non-destructive and non-contact temperature measurement technique that allows for real-time, full-field imaging. However, the limited spatial resolution of infrared detectors and the scarcity of mid- and far-infrared lenses have hindered its use in microscale applications. To address this, we introduce an infrared microscope that employs a bolometer-type infrared detector and a reflective objective lens, enabling high-resolution temperature measurements of microscale heating devices. The reflective objective lens used in the microscope introduces intensity reduction due to magnification and undesirable background radiation caused by its cavity effect. To mitigate these issues, we utilized a custom-built micro-blackbody for calibrating intensity reduction and eliminating background radiation. The proposed micro-infrared thermometry setup was characterized by MDTD and MRTD measurements, as well as an MTF curve with a pixel resolution of 6. 7 μ m /pixel and a spatial resolution of 12. 5 μ m. To evaluate the effectiveness of the micro-infrared thermometry, we fabricated a suspended microscale heating device that can exhibit a clear temperature distribution. The temperature distribution obtained using both the differential conversion and Fast Fourier-Transform methods to eliminate background radiation agreed well, with a maximum difference of 3.2 ° C and 4.1 ° C in the range from room temperature to 77 ° C and 145 ° C , respectively. Furthermore, we compared our experimental results with COMSOL simulations and found them to be reasonably consistent, with a maximum difference of 6.1 ° C and 7.0 ° C in the range from room temperature to 77 ° C and 145 ° C , respectively. • A micro-infrared thermometry setup using a reflective objective lens is proposed. • We achieve a pixel resolution of 6.7 μ m/pixel and a spatial resolution of 12.5 μ m. • The background radiation is removed using two different methods. • Local temperature distribution of a suspended microscale heating device is measured. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Reprodução Animal is the property of Revista Brasileira de Reproducao Animal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Infrared thermometry is a widely used technique for contactless temperature measurement, which is often conducted through semi-transparent media. In the present work, influences on the measurement results stemming from semi-transparent media and from the optical characteristics of the measurement setup are discussed. Results of two experimental setups, containing low, medium, and high transmission media are presented and compared to calculated data using a one-dimensional analytical approach and a three-dimensional ray-tracing algorithm. It is shown through modeling and experiments that the surroundings and, in particular, the (semi)transparent materials within the optical path are critical for accurate temperature measurements. [ABSTRACT FROM AUTHOR]

Milling is one of the most important and most complex cutting machining processes. During the milling process, the cross-section of the chip is variable. Also, all milling operations are interrupted processes. The cutting edge of the mill tooth periodically enters and exits from the contact with the workpiece, which leads to periodic heating and cooling during the machining. This periodic change of temperature significantly affects the process of tool wear and therefore the quality of the machined surface. This paper aims at modeling and optimizing the parameters of the machining prosess to achieve the minimum temperature. In order to perform optimization, it was necessary to perform temperature measurements for the various parameters of the machining process. An infrared camera was used for the temperature measurement. Then, based on the measured values, the mathematical modeling of the temperature was performed depending on the cutting speed, the feed rate and the depth of cut. This model is then optimized using two different optimization techniques. [ABSTRACT FROM AUTHOR]

Infrared thermal cameras have applications in a range of fields including security, agriculture, inspection, and health. In this paper, we are interested in their sensing properties, where we model and estimate the camera parameters required to transform digital counts to temperature values. Specifically, we propose a method to characterize the spatial deviation for the irradiance observed at the image plane for an uncooled focal-plane array camera deprived of an internal measurement of temperature. In our approach, we establish the relationship between the radiance emitted by a temperature varying blackbody chamber and the uncooled camera digital output. The model approximates this relationship as a quadratic polynomial whose variations are themselves approximated with another polynomial expression. Our results suggest a significant improvement over the commonly used Plancklike expression. [ABSTRACT FROM AUTHOR]

The electrical power within electronic components is connected with large quantity heat discharge which has to be removed in order to avoid risk of failure due to overheating. This paper presents an analysis of infrared camera implementation for correct temperature field estimation. This is necessary regarding the temperature measurement specifics with regard to power electronic elements during different regimes of exploitation. An infrared thermal camera Flir i7 has been used. Test measurements are performed and the influence of main measurement parameters over the thermal radiation of the bodies is discussed. Regression equation for temperature correction is calculated. [ABSTRACT FROM AUTHOR]

In friction stir welding (FSW), the microstructure, mechanical properties of the welded joint and the welding quality of the welding materials are affected by the temperature in the core area of the stirring tool. In this paper, the real-time detection of temperature in the core area of the stirring tool is realised, which is of great significance in improving the quality of the welding. A method for measuring the temperature in the core area is proposed based on the temperature measurement principle of the infrared thermal imager. Firstly, the relationship between the surface temperature of the welding material in the thermo-mechanically affected zone (TMAZ) and the temperature in the core area of the stirring tool is established based on the principle of temperature measurement using a thermal detector to produce an infrared image and the theory of heat radiation. Then, a heat source transfer model is constructed in the core area. The surface temperature of the welding material in the TMAZ is calculated using the Gauss method. Finally, the temperature in the core area of the stirring tool is obtained. At the same time, the accuracy and feasibility of the temperature measurement method is verified through measurement of the temperature of the core area by choosing to bury a thermocouple from the side of the welding material through transverse drilling. [ABSTRACT FROM AUTHOR]

During the discharge of the Experimental Advanced Superconducting Tokamak (EAST), the divertor target plate (DTP) accumulates a large amount of heat and suffers irreversible damages, so building of a temperature measurement system is crucial for guaranteeing the steady running of EAST. In this work, a radiation thermometer system which mainly consist of a high-speed infrared camera and an endoscope is employed to get surface temperature of upper divertor target plate (UDTP) between 20 and 200 °C. The spectral response function, the geometric factor and the radiation coming from the inner parts of the measurement system are obtained using a reference blackbody placed inside EAST based on multi-temperature calibration method. Meanwhile, in order to reduce temperature measurement error aroused by the emissivity of the divertor material, a nonlinear model is built between 20 and 200 °C in this paper to describe the dependence of spectral band emissivity on temperature. Finally the surface temperature of UDTP is obtained by solving the temperature equation using this emissivity model prior. Based on this method, the surface temperature of UDTP between 20 and 200 °C is measured and it can follow the changes of heating power in EAST real time. Compared with the traditional method in which the emissivity of the divertor material is deemed to a determinate constant, this method can efficiently improve the precision of temperature measurement. [ABSTRACT FROM AUTHOR]

During thermovision measurements, it is necessary to know the radiative temperature of surroundings of the tested object. For objects exposed to an open atmospheric space, such as buildings, the surroundings consists of the ground and the sky. The article concerns the measurement of sky temperature using an infrared camera with a long-wave spectral range of operation. This temperature is needed for the thermovision measurement of the real temperature of walls or roofs of buildings. It is also useful for calculating the emission of the sky over the entire spectral range, what is useful during the radiation heat exchange calculations. The use of an infrared camera for this purpose is a very convenient method, as the thermographer has this device at his disposal when performing object diagnostics. However, this measurement result is exposed to a systematic inaccuracy resulting from the radiation distribution of atmosphere inside the atmospheric window and the shape of infrared camera detector and lens technical characteristics. In addition, there is often a problem with measuring the relatively low temperature of the sky. The work contains an analysis and a proposal of the aforementioned problems solution. • Measurement of sky temperature by means of infrared camera. • Method of long-wave infrared camera use for measurement of very low sky temperature. • Measurement of temperature values outside the camera operating range. • Influence of infrared camera features on result of sky temperature measurement. [ABSTRACT FROM AUTHOR]

Precise transient temperature measurement is fundamental to estimate lifetime of power modules, especially those made with SiC transistors having very low thermal capacitance. This paper shows a precise method to estimate dynamic temperature of SiC components composing a power module used in three-phase inverters. This method is based on the use of a fast thermal camera to precisely measure thermal impedance of each die. Results of thermal camera measurements are validated by comparison with classical on-state resistance measurements to estimate junction temperature. Thermal impedance model is then coupled with precise loss calculation in order to predict dynamic die temperature during operation in a three-phase inverter. Measurements of the temperature variation of SiC dies conducting typical currents of a 540 V/7.5 kW three-phase inverter for aeronautical applications show the accuracy of the developed model for dynamic junction temperature estimation. • Precise estimation of dynamic junction temperature of SiC transistors for lifetime prediction of power modules used in three-phase inverters • It was found that the thermal impedance of the die does not significantly vary with its losses, but it does vary by 10-20% with respect to the current direction inside the die. • The method is based on temperature measured with fast and accurate infrared thermal camera, for different current direction and through the SiC die. [ABSTRACT FROM AUTHOR]

This study proposes a novel approach using an infrared camera to remotely measure the internal temperatures of a phase change material (PCM) in a quasi-2D cavity. The remote temperature measurements from the infrared camera were calibrated against a grid of thermocouples embedded in the PCM. The practical cases of experimental melting and freezing of a PCM in a thin circular cavity were used to develop and demonstrate the procedure. The results show good agreement between the infrared and thermocouple techniques in both space and time, confirming that the proposed technique could accurately estimate the PCM temperature remotely without the permanent installation of thermocouples. The method is then demonstrated on a separate experimental setup, using a rectangular geometry and a different PCM. The benefits and limitations of the proposed approach are also discussed. • A novel method to non-invasively measure PCM temperature using thermal imaging. • Quasi-two-dimensional encapsulation of PCM. • Calibration of the technique using a high-resolution grid of thermocouples. • Once calibrated, the technique measures PCM independently with good accuracy. [ABSTRACT FROM AUTHOR]