Real-time Thermal Monitoring Research Articles

Enhanced visualization of quench dynamics of HTS coils through embedded and distributed fiber optical sensing

The development of high-temperature superconducting (HTS) coils and magnets marks a significant advancement across various fields. To ensure their safety and reliability, thorough performance testing under extreme multi-field conditions is essential. This study introduces an innovative method that utilizes embedded and distributed fiber optical sensing (ED-FOS) in HTS pancake coils for precise real-time thermal monitoring and quench visualization. Incorporated during the manufacturing process, the ED-FOS sensors offer comprehensive and distributed measurements of thermal behavior during quenches. Our experiments demonstrate the ED-FOS effectively detects quenches caused by overcurrent and thermal issues. Unlike conventional techniques that rely on global voltage or magnetic field assessments, ED-FOS provides high spatiotemporal resolution and enhances temperature sensitivity. This capability allows for accurate, real-time identification and tracking of quench locations, which is essential for evaluating reliability and safety, as well as for improving performance. This advancement in HTS coil technology paves the way for wider application in critical fields and significantly enhances the design and management of superconducting coils.

Enhanced Long-Term Cycling Life of Ni-Rich NMC Cathodes in High-Voltage Lithium-Metal Batteries.

Li metal batteries (LMBs) have revived people's interest due to their high energy density. This work compares the cycling stability, structure stability, and thermal stability of Li||0.7Nb-NMC 9055 (0.7% Nb-modified LiNi0.9Co0.05Mn0.05O2) system in commercial carbonate electrolyte (1.0 M LiPF6 in EC/DMC) and designed carbonate electrolyte (1.0 M LiPF6-0.125 M LiNO3-0.025 M Mg(TFSI)2 in FEC-EMC). Li||0.7Nb-NMC 9055 battery with designed carbonate electrolyte exhibited superior capacity retention, 80% after ∼500 cycles. This can be explained by the improved mechanical integrity of the secondary particles and large reduced charge transfer resistance. Further, the real-time thermal monitoring of full cell via a high-precision, multimode calorimeter TAM IV Micro XL shows that the designed carbonate electrolyte with multisalt additive and FEC cosolvent has less heat release during the charging and discharge process, allowing these high-nickel (Ni) cathodes to reach closer to their full potential.

Dual-Modal Near-Infrared Organic Nanoparticles: Integrating Mild Hyperthermia Phototherapy with Fluorescence Imaging.

Our study seeks to develop dual-modal organic-nanoagents for cancer therapy and real-time fluorescence imaging, followed by their pre-clinical evaluation on a murine model. Integrating NIR molecular imaging with nanotechnology, our aim is to improve outcomes for early-stage cutaneous melanoma by offering more effective and less invasive methods. This approach has the potential to enhance both photothermal therapy (PTT) and Sentinel Lymph Node Biopsy (SLNB) procedures for melanoma patients. NIR-797-isothiocyanate was encapsulated in poly(D,L-lactide-co-glycolide) acid (PLGA) nanoparticles (NPs) using a two-step protocol, followed by thorough characterization, including assessing loading efficiency, fluorescence stability, and photothermal conversion. Biocompatibility and cellular uptake were tested in vitro on melanoma cells, while PTT assay, with real-time thermal monitoring, was performed in vivo on tumor-bearing mice under irradiation with an 808 nm laser. Finally, ex vivo fluorescence microscopy, histopathological assay, and TEM imaging were performed. Our PLGA NPs, with a diameter of 270 nm, negative charge, and 60% NIR-797 loading efficiency, demonstrated excellent stability and fluorescence properties, as well as efficient light-to-heat conversion. In vitro studies confirmed their biocompatibility and cellular internalization. In vivo experiments demonstrated their efficacy as photothermal agents, inducing mild hyperthermia with temperatures reaching up to 43.8 °C. Ex vivo microscopy of tumor tissue confirmed persistent NIR fluorescence and uniform distribution of the NPs. Histopathological and TEM assays revealed early apoptosis, immune cell response, ultrastructural damage, and intracellular material debris resulting from combined NP treatment and irradiation. Additionally, TEM analyses of irradiated zone margins showed attenuated cellular damage, highlighting the precision and effectiveness of our targeted treatment approach. Specifically tailored for dual-modal NIR functionality, our NPs offer a novel approach in cancer PTT and real-time fluorescence monitoring, signaling a promising avenue toward clinical translation.

Real-time shape sensing of large-scale honeycomb antennas with a displacement-gradient-based variable-size inverse finite element method

Real-time thermal deformation monitoring plays a crucial role in calibrating phase signals and maintaining satellite performance for large spaceborne antennas. The inverse finite element method (iFEM) represents a promising shape-sensing methodology applicable to monitor the three-dimensional displacement of structures through surface-measured strain. However, the high-accuracy reconstruction of large-scale structures involves a large number of inverse elements, which leads to the low level of computational efficiency. To address this issue, a displacement-gradient-based variable-size iFEM is proposed in this paper. According to the characteristics of deformation, this method optimizes the size of each inverse element to reduce the number of inverse elements required, which improves real-time performance and maintains the high accuracy of reconstruction. The real-time performance of the proposed method is verified by conducting a simulation test on a large-scale honeycomb antenna. According to the simulation results, the variable-size iFEM is applicable to achieve the same accuracy of reconstruction using fewer inverse elements than conventional iFEM. An experimental test is performed and the optimal variable-size discretization that balances accuracy and efficiency is determined. The results show that the maximum error of reconstructed displacement is less than 7.3 % and the reconstruction time is in no excess of 0.1 s.

A real-time thermal behaviour monitoring and analysis of a 500 kWh grid-connected battery energy storage system

Statistical analysis yields critical data for risk evaluation and management of a stationary battery energy storage system (BESS). Lithium-ion (Li-ion) batteries have attained huge attention for both stationary and non-stationary applications due to their lucrative features such as lightweight, high energy density efficiency, and long lifespan. However, detailed analysis and trends subjected to thermal behaviour of the device especially in grid-connected BESS application is still neglected. Therefore, this paper presents a statistical analysis for thermal behaviour of a grid connected BESS. The significance of Li-ion battery employing battery thermal management is presented, which can guarantee a reliable and safe operation as well as examining the effect of voltage, current and state of charge (SOC) on BESS operation. The large group of datasets recorded daily with five-minute intervals are difficult to be analysed numerically in a timely manner. Thus, the analysis can be made by visualizing the numerical data that was retrieved through representational state transfer (REST API) for easier interpretation and trend analysis. The visualization is made using Microsoft Power BI and presented in this paper.

An Er3+/Yb3+ Co-Doped Tellurite Temperature Sensor Based on Fluorescence Intensity Ratio Technology for Real-Time Thermal Monitoring of Automotive 3-D LiDAR

An Er³⁺/Yb³⁺ Co-Doped Tellurite Temperature Sensor Based on Fluorescence Intensity Ratio Technology for Real-Time Thermal Monitoring of Automotive 3-D LiDAR

Transmissive fluorescent temperature sensor based on Er3+/Yb3+/Mo6+ tri-doped tellurite fiber for real-time thermal monitoring of motors using the FIR technique.

In this paper, we fabricate a transmissive fluorescent temperature sensor (TFTS) that based on Er3+/Yb3+/Mo6+ tri-doped tellurite fiber, which has the advantages of compactness and simplicity, corrosion resistance, high stability and anti-electromagnetic interference. The doping of Mo6+ ions will enhance the up-conversion (UC) fluorescence emission efficiency of Er3+ ions, thus improving the signal-to-noise ratio of TFTS. Using the fluorescence intensity ratio (FIR) technique, the real-time thermal monitoring performance of TFTS is evaluated experimentally. Apart from good stability, its maximum relative sensitivity is 0.01068 K-1 at 274 K in the measured temperature range. In addition, it is successfully used to monitor the temperature variation of the stator core and stator winding of the motor in actual operation. The results show that the maximum error between the FIR-demodulated temperature and the reference temperature is less than 1.2 K, which fully confirms the effectiveness of the TFTS for temperature monitoring. Finally, the FIR-based TFTS in this work is expected to provide a new solution for accurate and real-time thermal monitoring of motors and the like.

A temperature sensor based on Er3+/Yb3+ co-doped tellurite fiber for real-time thermal monitoring of transformers

In this paper, a temperature sensor based on fluorescence intensity ratio (FIR) technique is prepared by the dual curing method. The pumping threshold is only 0.1 mW for the application of real-time thermal monitoring on small transformers. This not only greatly reduces the thermal effects accumulated by laser irradiation but also contributes to the integration and portability of the light source. Based on the FIR, the temperature information could be demodulated through tracking the fluorescence spectral changes. The basic temperature sensing characteristics of this sensor were evaluated, which showed that the maximum stability deviation and reproducibility error were within ±1.1 K and ±0.8 K, respectively. Notably, it has a maximum measurement error of only 0.61 K when applied to the temperature monitoring of transformers. And a fast time response of 2.1 s was exhibited in the cyclic exhalation experiment. This proposed sensor is suitable for mass production due to its resistance to electromagnetic interference, low pumping power, fast time response, excellent stability and reproducibility.

Evolution Law of Acoustic–Thermal Effect of Freeze–Thaw Sandstone Failure Based on Coupling of Multivariate Monitoring Information

The instability and failure of rock that has been frozen and thawed cause serious rock engineering accidents in cold regions. Exploring the precursor information of freeze–thaw rock failure is of great theoretical value and engineering significance. Real-time uniaxial compression acoustic thermal monitoring experiments were conducted on freeze–thaw sandstone, and non-contact rock fracture precursor warning indicators were proposed. According to the coupled analysis of acoustic–thermal monitoring information, a precursor information chain for freeze–thaw rocks was established in time and space, and the spatiotemporal evolution of damage and acoustic thermal effects of freeze–thaw sandstone under compressive load was studied. The freeze–thaw cycle enhances the sensitivity of acoustic–thermal precursor information. Significant synchronous changes in ring count often occur during the rapid expansion period of damage, which can provide an essential reference for the occurrence and intensification of damage. The sequence of precursor warning information during the process of freeze–thaw sandstone compression failure is in the order of thermal infrared temperature → acoustic emission ringing count → acoustic emission energy → infrared thermal image. Thermal infrared temperature and acoustic emission precursor information can help in prioritizing early warning of rock damage in terms of time. At the same time, thermal image anomalies can predict potential fracture areas of rocks.

A ratiometric fluorescent fiber sensor based on integrated silica and tellurite glass for real-time human thermal monitoring

In this paper, we propose and demonstrate a portable fiber sensor with integrated tellurite and silica for dynamic human thermal monitoring, where Er3+/Yb3+ co-doped tellurite glass is employed to generate upconversion fluorescence emission related to thermally coupled energy levels via near-infrared excitation for ratiometric thermometry. The molten tellurite glass is extracted into a silica tube using the negative pressure approach, allowing for intimate adhesion between different glass materials with considerable softening temperature differences. With a fast instantaneous response of 0.4–0.6 s and an absolute error of −0.45–0.36 K, the sensor can accurately and timely capture small temperature fluctuations. The sensor is placed in the mouth or attached to the hand skin to measure the body temperature continually. It is also positioned in the mouth exhalation and nose breathing environments to monitor thermal activities in real-time, offering a new, highly reliable method for human health monitoring.

Holographic Focused Ultrasound Hyperthermia System for Uniform Simultaneous Thermal Exposure of Multiple Tumor Spheroids.

Hyperthermia is currently used to treat cancer due to its ability to radio- and chemo-sensitize and to stimulate the immune response. While ultrasound is non-ionizing and can induce hyperthermia deep within the body non-invasively, achieving uniform and volumetric hyperthermia is challenging. This work presents a novel focused ultrasound hyperthermia system based on 3D-printed acoustic holograms combined with a high-intensity focused ultrasound (HIFU) transducer to produce a uniform iso-thermal dose in multiple targets. The system is designed with the aim of treating several 3D cell aggregates contained in an International Electrotechnical Commission (IEC) tissue-mimicking phantom with multiple wells, each holding a single tumor spheroid, with real-time temperature and thermal dose monitoring. System performance was validated using acoustic and thermal methods, ultimately yielding thermal doses in three wells that differed by less than 4%. The system was tested in vitro for delivery of thermal doses of 0-120 cumulative equivalent minutes at 43 °C (CEM43) to spheroids of U87-MG glioma cells. The effects of ultrasound-induced heating on the growth of these spheroids were compared with heating using a polymerase chain reaction (PCR) thermocycler. Results showed that exposing U87-MG spheroids to an ultrasound-induced thermal dose of 120 CEM43 shrank them by 15% and decreased their growth and metabolic activity more than seen in those exposed to a thermocycler-induced heating. This low-cost approach of modifying a HIFU transducer to deliver ultrasound hyperthermia opens new avenues for accurately controlling thermal dose delivery to complex therapeutic targets using tailored acoustic holograms. Spheroid data show that thermal and non-thermal mechanisms are implicated in the response of cancer cells to non-ablative ultrasound heating.

The early warning for overcharge thermal runaway of lithium-ion batteries based on a composite parameter

The wider application of lithium-ion batteries(LIBs)is restricted by electric abuse. Moreover, overcharging is an important reason for thermal runaway. In order to prevent the occurrence of overcharge thermal runaway (OTR) events, a new three-level warning method is presented. By comparing Fiber Bragg Grating (FBG) and thermocouple real-time thermal monitoring, FBG shows a better temperature response. The OTR experiment is carried out, and the whole process of lithium battery thermal runaway under different overcharge rates (1 C, 1.5 C, and 2 C) is divided into three stages. Based on the cross-sensitivity of strain and temperature for FBG, a composite parameter (virtual temperature) affected by temperature and strain is proposed as an early warning index. Combining with the changes in virtual temperature, surface temperature, and the early voltage variation of thermal runaway, a three-level early warning model for thermal runaway is proposed. The first-level warning: the temperature difference between virtual temperature and surface temperature reaches 5 °C. The second-level warning: the virtual temperature reaches 70 °C. The third-level warning: the surface temperature reaches 80 °C. This method can provide a reference for monitoring and early warning of LIBs in energy storage power stations.

Plug-in tip sensor based on upconversion fluorescence in Er3+/Yb3+ co-doped tellurite glass for thermal monitoring of a miniature winding coil.

We demonstrate a plug-in tip sensor with a maximum cross section diameter of only 1 mm for real-time thermal monitoring of a high-density miniature winding coil, which can meet the miniaturization development needs of electromagnetic actuators. Due to the high upconversion luminescence efficiency, tellurite glass with an optimized Er3+/Yb3+ doping ratio is adhered to the end face of silica fiber for a temperature-sensitive tip. Temperature information is demodulated using the fluorescence intensity ratio technique, yielding a nonlinear response with R2 up to 0.9978. Within a wide temperature range of 253.55-442.45 K, the tip sensor exhibits good repeatability, excellent stability, high sensitivity of 52.7 × 10-4 K-1, small absolute error within ±1 K, and fast time response of 2.03 s. It has been successfully proven to be a miniaturized device with strong anti-interference ability for the health management of high-density winding coils.

A Compact Fluorescent Probe for Real-Time Thermal Monitoring of Chips

In this paper, a compact fluorescent probe based on fluorescence intensity ratio (FIR) technique is proposed for real-time thermal monitoring of chips, the sensing unit of which is based on a self-made tellurite optical fiber (TOF) co-doped with Er <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> /Yb <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> ions. Temperature information was demodulated by analyzing the up-conversion fluorescence emission spectra generated using a 980 nm laser pump. Experimentally characterized the relationship between the FIR related to two thermally coupled energy levels and the ambient temperature, and on-line investigated the temperature change of Central Processing Unit (CPU) and North Bridge Chip for about 80 min during the cycle startup/shutdown process. The proposed probe exhibits a fast time response of about 1.1 s in a step temperature-varying environment and a small absolute error of <0.85 K in the real-time thermal monitoring of the CPU. To the best of our knowledge, this is the first report on fluorescent probes for thermal detection of chips. The proposed probe has the characteristics of anti-electromagnetic interference, explosion-proof, corrosion resistance, and can effectively avoid cross-sensitivity problems caused by environmental parameters. It provides a novel and reliable method for real-time thermal monitoring of chips.

Real-time mechanical and thermal monitoring of lithium batteries with PVDF-TrFE thin films integrated within the battery

Lithium battery cells typically have a sealed structure. Throughout the life cycle of such batteries, electric/chemical/force/thermal multi-field coupling interactions occur during the service process. Therefore, in situ characterization of the internal mechanics and temperature parameters of batteries is vital for managing their safety. In this study, a lithium-ion battery pressure/temperature monitoring micro thin-film sensor based on a flexible printed circuit anode current collector is formed by using a piezoelectric/pyroelectric poly (vinylidene fluoride-trifluoroethylene) material. The micro thin-film sensor is integrated within the battery and can monitor the mechanical and thermal damage inside the battery in real-time without interfering with the battery operation. The micro thin-film sensor prepared following this method provides sufficient early warning of battery failure and can significantly improve battery safety performance.

Real-time estimation of junction temperature in IGBT inverter with a simple parameterized power loss model

System-level thermal modelling of electric drive systems requires simple thermal models coupled with each other by the operation parameters of the drive systems. This paper presents a simple parameterized power loss model for insulated gate bipolar transistor (IGBT) inverters, in which variables are relevant to the powertrain operation conditions and are routinely monitored. Combined with a two-impedance thermal model of the inverter with parameters fitted to the results of computation fluid dynamics (CFD) simulations, the resulted real-time model can provide accurate estimations of the junction temperature. The present power loss model combined with the simple two-impedance thermal model is very suitable to be used in system-level real-time thermal monitoring of an integrated electric drive system.

Antibody-functionalized theranostic protein nanoparticles for the synergistic deep red fluorescence imaging and multimodal therapy of ovarian cancer.

Among women, ovarian cancer is the fifth most frequent type of cancer, and despite benefiting from current standard treatment plans, 90% of patients relapse in the subsequent 18 months and, eventually, perish. As a result, via embracing nanotechnological advancements in the field of medical science, researchers working in the areas of cancer therapy and imaging are looking for the next breakthrough treatment strategy to ensure lower cancer recurrence rates and improved outcomes for patients. Herein, we design a novel phototheranostic agent with optical features in the biological window of the electromagnetic spectrum via encapsulating a newly synthesized phthalocyanine dye within biocompatible protein nanoparticles, allowing the targeted fluorescence imaging and synergistic dual therapy of ovarian cancer. The nanosized agent displays great biocompatibility and enhanced aqueous biostability and photothermal activity, as well as high reactive-oxygen-species generation efficiency. To achieve the active targeting of the desired malignant tissue and suppress the rapid clearance of the photosensitive agent from the peritoneal cavity, the nanoparticles are biofunctionalized with an anti-folate receptor antibody. A2780 ovarian cancer cells are employed to confirm the improved targeting capabilities and the in vitro cytotoxic efficiency of the theranostic nanoparticles after exposure to a 660 nm LED lamp; upon measurement via MTT and flow cytometry assays, a significant 95% decrease in the total number of viable cells is seen. Additionally, the therapeutic performance of our newly designed nanoparticles was evaluated in vivo, via real-time thermal monitoring and histopathological assays, upon the irradiation of tumour-bearing mice with a 660 nm LED lamp (0.05 W cm-2). Foremost, separately from steady-state fluorescence imaging, we found that, via utilizing FLIM investigations, the differences in fluorescence lifetimes of antibody biofunctionalized and non-functionalized nanoparticles can be correlated to different intracellular localization and internalization pathways of the fluorescent agent, which is relevant for the development of a cutting-edge method for the detection of cancer cells that overexpress folate receptors at their surfaces.

Development of an IoT and BIM-based automated alert system for thermal comfort monitoring in buildings

A comfortable thermal indoor environment is crucial for occupants’ well-being and productivity. Building Management System (BMS) is usually used to monitor the thermal condition of buildings. One of BMS’s main challenges is in the data visualization stage, in which 2D vector graphics are used, which is not fully interactive and can only be manipulated by a trained operator. Building Information Modeling (BIM) has emerged as a useful tool in the construction industry, which can be applied in all stages of a project lifecycle. The use of BIM in facilities management is currently limited since BIM applications have primarily been implemented within the design and construction phases. The main objective of this study is to integrate a sensor-based alert system into BIM models for thermal comfort monitoring in buildings during the operational phase and visualize a building’s thermal condition virtually. In order to improve the performance of environmental monitoring management of buildings in smart cities, this research presents a newly developed integrated solution based on a BIM platform and Internet of Things (IoT). The designed prototype explores the integration of commercial BIM platforms with sensor data to create a self-updating BIM model to provide real-time thermal condition monitoring based on the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Standard within an office environment. The temperature and humidity values, measured by sensors, are sent to the MySQL database server. An integrated workflow was developed to compile, standardize, integrate, and visualize monitoring data in a BIM environment to facilitate interpretation, analysis, and monitoring data exchange. The developed system was able to detect the time and location of a case study office room experiencing the levels of thermal comfort/discomfort based on the targeted thresholds. In this case, thirteen levels of thermal discomfort cases, out of forty-nine data points during the test, were detected, and the developed system was also able to generate a trigger and transmit alarms to facility managers via their wireless devices in real-time. The results demonstrate that the proposed system is a visually effective monitoring system for environmental monitoring management. The fully automated developed system is expected to provide a robust and practical tool for reliable data collection, analysis, and visualization to facilitate intelligent monitoring of the thermal condition in buildings and help decision-makers make faster and better decisions, which may help in maintaining the level of occupants’ thermal comfort to a satisfactory level.

Real-time and Contactless Mold Thermal Monitoring: Improving Metallurgy, Quality and Productivity of Billets and Blooms

Today the mold thermal mapping technology is typically applied to the CCMs for slabs with solutions based on the installation of thermocouples (TC) or optical fibre cables (OFC), inserted into channels machined in the plate molds. The final installation is complex, since every single mold must be machined and the quantity of cables is considerable, making every mold change a complex and time-consuming activity. Extending TC or OFC application to billets and blooms would require invasive and expensive CNC machining of the curved mold tubes. In order to overcome these limits, Ergolines designed a new system based on contactless ultrasound technology which provides the real-time mold thermal map without the need to machine the copper, offering a new reliable tool also to the CCMs for small sections. By providing real-time data of the thermal distribution of the mold, Ergolines’ system can be fruitfully used by the technical personnel to improve the casting practice, the steel quality and the plant productivity.

A Primer on Magnetic Resonance-Guided Laser Interstitial Thermal Therapy for Medically Refractory Epilepsy.

Epilepsy surgery that eliminates the epileptogenic focus or disconnects the epileptic network has the potential to significantly improve seizure control in patients with medically intractable epilepsy. Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) has been an established option for epilepsy surgery since the US Food and Drug Administration cleared the use of MRgLITT in neurosurgery in 2007. MRgLITT is an ablative stereotactic procedure utilizing heat that is converted from laser energy, and the temperature of the tissue is monitored in real-time by MR thermography. Real-time quantitative thermal monitoring enables titration of laser energy for cellular injury, and it also estimates the extent of tissue damage. MRgLITT is applicable for lesion ablation in cases that the epileptogenic foci are localized and/or deep-seated such as in the mesial temporal lobe epilepsy and hypothalamic hamartoma. Seizure-free outcomes after MRgLITT are comparable to those of open surgery in well-selected patients such as those with mesial temporal sclerosis. Particularly in patients with hypothalamic hamartoma. In addition, MRgLITT can also be applied to ablate multiple discrete lesions of focal cortical dysplasia and tuberous sclerosis complex without the need for multiple craniotomies, as well as disconnection surgery such as corpus callosotomy. Careful planning of the target, the optimal trajectory of the laser probe, and the appropriate parameters for energy delivery are paramount to improve the seizure outcome and to reduce the complication caused by the thermal damage to the surrounding critical structures.