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 temperature measurement


Toward Developing Machine-Learning-Aided Tools for the Thermomechanical Monitoring of Nuclear Reactor Components

Machado, Luiz Aldeia, Leite, Victor Coppo, Merzari, Elia, Motta, Arthur, Ponciroli, Roberto, Ibarra, Lander, Charlot, Lise

arXiv.org Artificial Intelligence

Proactive maintenance strategies, such as Predictive Maintenance (PdM), play an important role in the operation of Nuclear Power Plants (NPPs), particularly due to their capacity to reduce offline time by preventing unexpected shutdowns caused by component failures. In this work, we explore the use of a Convolutional Neural Network (CNN) architecture combined with a computational thermomechanical model to calculate the temperature, stress, and strain of a Pressurized Water Reactor (PWR) fuel rod during operation. This estimation relies on a limited number of temperature measurements from the cladding's outer surface. This methodology can potentially aid in developing PdM tools for nuclear reactors by enabling real-time monitoring of such systems. The training, validation, and testing datasets were generated through coupled simulations involving BISON, a finite element-based nuclear fuel performance code, and the MOOSE Thermal-Hydraulics Module (MOOSE-THM). We conducted eleven simulations, varying the peak linear heat generation rates. Of these, eight were used for training, two for validation, and one for testing. The CNN was trained for over 1,000 epochs without signs of overfitting, achieving highly accurate temperature distribution predictions. These were then used in a thermomechanical model to determine the stress and strain distribution within the fuel rod.


Data-driven Power Loss Identification through Physics-Based Thermal Model Backpropagation

Scarpa, Mattia, Pase, Francesco, Carli, Ruggero, Bruschetta, Mattia, Toso, Franscesco

arXiv.org Artificial Intelligence

-- Digital twins for power electronics require accurate power losses whose direct measurements are often impractical or impossible in real-world applications. This paper presents a novel hybrid framework that combines physics-based thermal modeling with data-driven techniques to identify and correct power losses accurately using only temperature measurements. Our approach leverages a cascaded architecture where a neural network learns to correct the outputs of a nominal power loss model by backpropagating through a reduced-order thermal model. We explore two neural architectures, a bootstrapped feedforward network, and a recurrent neural network, demonstrating that the bootstrapped feedforward approach achieves superior performance while maintaining computational efficiency for real-time applications. Between the interconnection, we included normalization strategies and physics-guided training loss functions to preserve stability and ensure physical consistency. Experimental results show that our hybrid model reduces both temperature estimation errors (from 7.2 6.8 C to 0.3 0.3 C) and power loss prediction errors (from 5.4 6.6W to 0.2 0.3W) compared to traditional physics-based approaches, even in the presence of thermal model uncertainties. This methodology allows us to accurately estimate power losses without direct measurements, making it particularly helpful for real-time industrial applications where sensor placement is hindered by cost and physical limitations. This paper has been accepted for presentation at the 23rd IEEE European Control Conference 2025 IEEE. Thermal management and sensing play a critical role in many industrial applications that rely on power electronics.


Data-Driven vs Traditional Approaches to Power Transformer's Top-Oil Temperature Estimation

Tembo, Francis, Bragone, Federica, Laneryd, Tor, Barreau, Matthieu, Morozovska, Kateryna

arXiv.org Artificial Intelligence

Power transformers are subjected to electrical currents and temperature fluctuations that, if not properly controlled, can lead to major deterioration of their insulation system. Therefore, monitoring the temperature of a power transformer is fundamental to ensure a long-term operational life. Models presented in the IEC 60076-7 and IEEE standards, for example, monitor the temperature by calculating the top-oil and the hot-spot temperatures. However, these models are not very accurate and rely on the power transformers' properties. This paper focuses on finding an alternative method to predict the top-oil temperatures given previous measurements. Given the large quantities of data available, machine learning methods for time series forecasting are analyzed and compared to the real measurements and the corresponding prediction of the IEC standard. The methods tested are Artificial Neural Networks (ANNs), Time-series Dense Encoder (TiDE), and Temporal Convolutional Networks (TCN) using different combinations of historical measurements. Each of these methods outperformed the IEC 60076-7 model and they are extended to estimate the temperature rise over ambient. To enhance prediction reliability, we explore the application of quantile regression to construct prediction intervals for the expected top-oil temperature ranges. The best-performing model successfully estimates conditional quantiles that provide sufficient coverage.


Fever Detection with Infrared Thermography: Enhancing Accuracy through Machine Learning Techniques

Razmara, Parsa, Khezresmaeilzadeh, Tina, Jenkins, B. Keith

arXiv.org Artificial Intelligence

The COVID-19 pandemic has underscored the necessity for advanced diagnostic tools in global health systems. Infrared Thermography (IRT) has proven to be a crucial non-contact method for measuring body temperature, vital for identifying febrile conditions associated with infectious diseases like COVID-19. Traditional non-contact infrared thermometers (NCITs) often exhibit significant variability in readings. To address this, we integrated machine learning algorithms with IRT to enhance the accuracy and reliability of temperature measurements. Our study systematically evaluated various regression models using heuristic feature engineering techniques, focusing on features' physiological relevance and statistical significance. The Convolutional Neural Network (CNN) model, utilizing these techniques, achieved the lowest RMSE of 0.2223, demonstrating superior performance compared to results reported in previous literature. Among non-neural network models, the Binning method achieved the best performance with an RMSE of 0.2296. Our findings highlight the potential of combining advanced feature engineering with machine learning to improve diagnostic tools' effectiveness, with implications extending to other non-contact or remote sensing biomedical applications. This paper offers a comprehensive analysis of these methodologies, providing a foundation for future research in the field of non-invasive medical diagnostics.


Accelerated Proton Resonance Frequency-based Magnetic Resonance Thermometry by Optimized Deep Learning Method

Xu, Sijie, Zong, Shenyan, Mei, Chang-Sheng, Shen, Guofeng, Zhao, Yueran, Wang, He

arXiv.org Artificial Intelligence

Proton resonance frequency (PRF) based MR thermometry is essential for focused ultrasound (FUS) thermal ablation therapies. This work aims to enhance temporal resolution in dynamic MR temperature map reconstruction using an improved deep learning method. The training-optimized methods and five classical neural networks were applied on the 2-fold and 4-fold under-sampling k-space data to reconstruct the temperature maps. The enhanced training modules included offline/online data augmentations, knowledge distillation, and the amplitude-phase decoupling loss function. The heating experiments were performed by a FUS transducer on phantom and ex vivo tissues, respectively. These data were manually under-sampled to imitate acceleration procedures and trained in our method to get the reconstruction model. The additional dozen or so testing datasets were separately obtained for evaluating the real-time performance and temperature accuracy. Acceleration factors of 1.9 and 3.7 were found for 2 times and 4 times k-space under-sampling strategies and the ResUNet-based deep learning reconstruction performed exceptionally well. In 2-fold acceleration scenario, the RMSE of temperature map patches provided the values of 0.888 degree centigrade and 1.145 degree centigrade on phantom and ex vivo testing datasets. The DICE value of temperature areas enclosed by 43 degree centigrade isotherm was 0.809, and the Bland-Altman analysis showed a bias of -0.253 degree centigrade with the apart of plus or minus 2.16 degree centigrade. In 4 times under-sampling case, these evaluating values decreased by approximately 10%. This study demonstrates that deep learning-based reconstruction can significantly enhance the accuracy and efficiency of MR thermometry for clinical FUS thermal therapies.


Spatially-resolved Thermometry from Line-of-Sight Emission Spectroscopy via Machine Learning

Kang, Ruiyuan, Kyritsis, Dimitrios C., Liatsis, Panos

arXiv.org Artificial Intelligence

A methodology is proposed, which addresses the caveat that line-of-sight emission spectroscopy presents in that it cannot provide spatially resolved temperature measurements in nonhomogeneous temperature fields. The aim of this research is to explore the use of data-driven models in measuring temperature distributions in a spatially resolved manner using emission spectroscopy data. Two categories of data-driven methods are analyzed: (i) Feature engineering and classical machine learning algorithms, and (ii) end-to-end convolutional neural networks (CNN). In total, combinations of fifteen feature groups and fifteen classical machine learning models, and eleven CNN models are considered and their performances explored. The results indicate that the combination of feature engineering and machine learning provides better performance than the direct use of CNN. Notably, feature engineering which is comprised of physics-guided transformation, signal representation-based feature extraction and Principal Component Analysis is found to be the most effective. Moreover, it is shown that when using the extracted features, the ensemble-based, light blender learning model offers the best performance with RMSE, RE, RRMSE and R values of 64.3, 0.017, 0.025 and 0.994, respectively. The proposed method, based on feature engineering and the light blender model, is capable of measuring nonuniform temperature distributions from low-resolution spectra, even when the species concentration distribution in the gas mixtures is unknown.


In-Situ Sensing and Dynamics Predictions for Electrothermally-Actuated Soft Robot Limbs

Sabelhaus, Andrew P., Mehta, Rohan K., Wertz, Anthony T., Majidi, Carmel

arXiv.org Artificial Intelligence

Untethered soft robots that locomote using electrothermally-responsive materials like shape memory alloy (SMA) face challenging design constraints for sensing actuator states. At the same time, modeling of actuator behaviors faces steep challenges, even with available sensor data, due to complex electrical-thermal-mechanical interactions and hysteresis. This article proposes a framework for in-situ sensing and dynamics modeling of actuator states, particularly temperature of SMA wires, which is used to predict robot motions. A planar soft limb is developed, actuated by a pair of SMA coils, that includes compact and robust sensors for temperature and angular deflection. Data from these sensors are used to train a neural network based on the long short-term memory (LSTM) architecture to model both unidirectional (single SMA) and bidirectional (both SMAs) motion. Predictions from the model demonstrate that data from the temperature sensor, combined with control inputs, allow for dynamics predictions over extraordinarily long open-loop timescales (10 minutes) with little drift. Prediction errors are on the order of the soft deflection sensor's accuracy. This architecture allows for compact designs of electrothermally-actuated soft robots that include sensing sufficient for motion predictions, helping to bring these robots into practical application.


CEIA USA Advances Operations With New Security Checkpoint Solution

#artificialintelligence

CEIA USA, a premier provider of high-performance Security Metal Detectors, announced the availability of the new CEIA 02PN20v3 anti-COVID security checkpoint. The rapid spread of COVID-19 infections has required the introduction of containment measures at all levels including the use of face masks, social distancing and also the measurement of body temperature as an indicator of possible virus infections. Security checkpoints at the entries to airports and other sensitive buildings should now be equipped with security systems compliant with these new measures. The new 02PN20v3 security checkpoint provides (1) detection of metallic threats with minimum contact, (2) automatic detection of high body surface temperature, and (3) throughput control with check of transit direction and completion including optimized touchscreen user interface for managing checks and displaying alerts. The 02PN20v3 offers the detection of metallic threats in accordance with security level settings by a next-generation inductive detector with high range uniformity and excellent discrimination of metal personal effects thereby reducing the number of necessary secondary checks.


Video shows billion dollar InSight digging robot FINALLY working again after SEVEN months

Daily Mail - Science & tech

NASA's digging probe on the InSight Mars lander is finally making progress again after assistance from the lander's robotic arm helped it gain purchase in the soil. The probe -- dubbed'the Mole' -- began hammering its way into the soil of the Red Planet in March, but after digging a few inches it found itself unable to go deeper. Experts believe that the probe encountered an unexpected layer of cemented soil that wasn't falling into the hole the device had dug. The result was that there wasn't enough purchase between the probe and the surrounding soil for the Mole to push down any deeper. After first trying to compact the surrounding soil with InSight's instrument arm, engineers tried pushing the mole sideways against its hole.