Accurate Temperature Monitoring Research Articles

Estimation of battery temperature during drive cycle operation by the time evolution of voltage and current

During the operation of electric vehicles, accurate temperature monitoring of lithium-ion batteries by battery management system is crucial to their safety. However, temperature sensors possess limitations as they necessitate regular calibration to avoid inaccuracies, which can be challenging to accomplish in certain scenarios. As an alternative, a general sensorless temperature estimation framework is developed in this study to either serve as a complementary approach alongside sensors or function independently to ensure reliable temperature measurement. The proposed framework relies solely on data regarding battery voltage and current measurements, and this information is employed to determine the parameters of the equivalent circuit model via the vector-type recursive least squares algorithm in the first step. In the second step, these parameters and the voltage/current data serve as the input to the deep neural network (DNN) to estimate the instantaneous battery surface temperature during dynamic driving cycles under various ambient temperatures and degradation scenarios. To reflect the effect of past battery operation on the current temperature, a newly defined current integral function is proposed, by which the input time length of the DNN model is suggested. Four combinations of the model input are studied, and the best input option yields an average estimation error of the battery temperature that falls below 0.5 °C.

Design Implementation of a Logger-Based Digital Thermometer

LM35 temperature sensor is a widely used 3-terminal sensor known for its precise temperature measurement capabilities without the need for external calibration circuitry. With a sensitivity of 10mV/°C, it operates within a temperature range of -55°C to 150°C, with an error margin of 0.5°C. This paper presents the development and testing of a logger-based digital thermometer using LM35 sensor, integrated with a dsPIC30F4013 digital signal processing controller, an LCD, a real-time clock (DS1307), and other essential components. The methodology involves the analysis of the sensor's sensitivity and its response under both stress and non-stress temperature conditions. The findings indicate that the sensor's output closely follows the theoretical sensitivity, with a negligible offset, ensuring accurate temperature measurements. Comparative analysis with a standard laboratory thermometer suggests that the digital sensor provides superior precision, with an error margin of ±0.01°C. The results confirm LM35's suitability for accurate ambient temperature monitoring and validation of environmental temperature fluctuations.

A high‐precision voltage reference with a curvature‐compensated bandgap for fluorescence detection

SummaryFluorescent optical fiber temperature sensors require accurate online temperature monitoring in hazardous environments with strong electromagnetic fields, high voltages, flammability, or explosiveness. This imposes stringent requirements on the temperature coefficient stability of the bandgap reference (BGR) circuit. To address these challenges, this paper proposes a high‐order curvature compensation bandgap reference (HCC_BGR) circuit fabricated using a 0.18‐μm bipolar‐CMOS‐DMOS (BCD) process. A traditional first‐order bandgap reference (TRA_BGR) circuit is also fabricated for comparison. Experimental results demonstrate that the proposed HCC_BGR circuit generates a stable 1.22‐V reference voltage with a low‐temperature coefficient of 5.56 ppm/°C from −20°C to 85°C. Compared to the TRA_BGR circuit, the HCC_BGR reduces the temperature coefficient by 3.07 times. Furthermore, the low‐dropout regulator (LDO) using the proposed HCC_BGR exhibits excellent line sensitivity of 1.52%/V from 3.4 to 5 V.

Gated recurrent unit-based data-driven model for predicting pot temperature in induction cooking systems

On an induction cooker, accurate pot temperature monitoring can cut down on energy use and prevent overheating. It can be challenging to create a mathematical model for predicting pot temperature, though, because of the different materials and sizes of the pots and the intricate electromagnetic coupling between the induction coil and the pot. To solve this problem, this paper offered a data-driven model that forecasts pot temperature by the inverter module's measured temperature. We used thermocouples in contact with the bottom surfaces of the pots and inverters to record time-series data on the temperatures of the devices to make accurate predictions. This information was gathered under a variety of circumstances, including various pot sizes and materials, various power and temperature settings, and various water levels. We used a gated recurrent unit-based autoencoder to reduce noise in the inverter temperature that was brought on by the cooling fan operation. The data-driven model was then trained using a variety of machine learning and deep learning techniques, including support vector machines, decision trees, linear regression, artificial neural networks, and gated recurrent units. Finally, we compared the predicted and measured pot temperatures to validate the data-driven models that had been learned. According to the statistical findings, there was a 3 °C or so median temperature difference between predicted and actual temperatures.

Biocompatible Upconverting Nanoprobes for Dual-Modal Imaging and Temperature Sensing.

The demand for multimodal nanomaterials has intensified in recent years driven by the need for ultrasensitive bioimaging probes and accurate temperature monitoring in biological objects. Among the different multimodal nanomaterials that have been extensively studied in the past decade, upconverting nanoparticles are among the most promising. In this paper, we report the synthesis of upconverting nanoparticles with complex core-shell compositions, capable of being excited by 808 or 980 nm laser irradiation and exhibiting a good MRI response. The synthesized nanoparticles also demonstrated high colloidal stability in both aqueous and biological media as well as temperature-sensing capabilities, including the physiological range. Furthermore, the upconversion nanoparticles exhibited significantly lower cytotoxicity for HEK293T cells than the commercially available MRI contrast agent Gd-DTPA.

Analysis of the Effect of Copper Doping on the Optoelectronic Properties of Indium Oxide Thin Films and the Thermoelectric Properties of an In2O3/Pt Thermocouple

The detection and real-time monitoring of temperature parameters are important, and indium oxide-based thin film thermocouples can be integrated on the surface of heaters because they operate normally under harsh conditions and provide accurate online temperature monitoring. The higher stability and appropriate optical and electrical properties of In2O3 make it very suitable as an electrode material for thermocouple sensors. This work demonstrates that copper doping can alter the optical and electrical properties of In2O3 films and regulate the output performance of thermocouples. Copper-doped In2O3 thin films were prepared using the magnetron co-sputtering method. The doping concentration of Cu was controlled using direct current (DC) power. An In2O3/Pt thermocouple sensor was prepared, and the optoelectronic and thermocouple properties were adjusted by changing the copper doping content. The thickness valve of the thin film sample was 300 nm. The results of the X-ray diffraction suggested that the structure of the doped In2O3 thin films was cubic. The results of the energy-dispersive X-ray analysis revealed that Cu was doped into the In2O3 thin films. All deposited films were n-type semiconductor materials according to Hall effect testing. The 4.09 at% Cu-doped thin films possessed the highest resistivity (30.2 × 10−3 Ω·cm), a larger carrier concentration (3.72 × 1020 cm−3), and the lowest carrier mobility (0.56 cm2V−1s−1). The optical band gap decreased from 3.76 to 2.71 eV with an increase in the doping concentration, and the transmittance of the film significantly reduced. When the DC power was increased, the variation range of Seebeck coefficient for the In2O3/Pt thermocouple was 152.1–170.5 μV/°C, and the range of thermal output value was 91.4–102.4 mV.

Thin-Film Transistor-Based Sensor Interface Circuits Enabling Distributed Local In-Module Solar Cell Temperature Monitoring

Accurate efficiency prediction, improved reliability, and extended lifetime of solar modules are the key driving factors for investment and research in photovoltaic (PV) systems. Enhanced performance and more refined models are realized by incorporating data derived from localized monitoring of solar modules. This work combines interface circuits designed in flexible thin-film transistors (TFTs) with distributed temperature sensors integrated into solar cell lamination enabling in-module within-cell PV monitoring. A TFT multiplexer selects between sensors and is commanded through a serial peripheral interface (SPI) to reduce the IO connections, while the low offset unity-gain TFT buffer enables precise signal transfer. The in-cell sensors together with TFT read-out circuitry demonstrate accurate outdoor temperature monitoring, comparable to silicon integrated circuits.

TEMPERATURE CORRECTION METHOD OF RADIATION THERMOMETER BASED ON THE NONLINEAR MODEL FITTED FROM SPECTRAL EMISSIVITY MEASUREMENTS OF Ni-BASED ALLOY

Accurate temperature monitoring of heat transfer tube is crucial for safe and efficient operation of nuclear power plants, and radiation thermometer is a common method used for this purpose. This paper thoroughly introduces the measurement principle of the radiation thermometer with an operation wavelength range of 8-14 μm. The spectral emissivity of Ni-based alloy DD6 under argon condition is measured using an emissivity measurement setup equipped with a Fourier-transform infrared (FTIR) spectrometer. By integrating the spectral emissivity in the working wavelength range, the spectral band emissivity can be calculated to enhance the accuracy of calculation results obtained by radiation thermometer. And curve of the spectral band emissivity with temperature can be accurately described by the nonlinear model. The radiation and corrected temperatures are compared with the temperatures obtained by a K-type thermocouple to verify the availability of the spectral band emissivity obtained by fitting the nonlinear model. The temperature comparison results demonstrate that the corrected temperatures are closer to the true temperature than the radiation temperature, with a maximum temperature deviation of only 4.38°C. The combined relative uncertainty of true temperature measurement by the radiation thermometer at temperatures of 200, 300, 400, and 500°C is less than 3.60%.

Precise Synergistic Photothermal Therapy Guided by Accurate Temperature‐Dependent NIR‐II Fluorescence Imaging

AbstractPhotothermal therapy (PTT) is considered a promising treatment strategy for solid tumors. However, local hyperthermia (over 45°C) during PTT can cause severe side effects in neighboring healthy tissues. PTT with accurate temperature feedback is a compelling strategy to ablate tumors and reduce side effects, but it still faces challenges. Here, a new kind of phototheranostic nanoparticle, namely 17‐RF@Ag2Se is developed, enabling in vivo NIR‐II fluorescence tracking, PTT and fluorescence nanothermometry as well as synergistic heat‐shock protein (HSP) inhibition. Precise PTT with high spatiotemporal resolution is achieved with the help of the designed NIR‐II fluorescence imaging‐photothermal therapy linkage apparatus. Upon intravenous injection, 17‐RF@Ag2Se is specifically accumulated in tumors targeted by the overexpressed integrin αvβ3, which is monitored by NIR‐II fluorescence imaging of Ag2Se QDs. Further, the release of HSP inhibitor, tanespimycin (17‐AAG), enhances the thermosensitivity of tumor cells. Subsequently, the internal temperature of the tumor is precisely monitored and adjusted during PTT via the temperature‐dependent NIR‐II fluorescence feedback of Ag2Se QDs and the linkage apparatus calibration, thereby achieving efficient and safe tumor PTT. Also, the results present a new method for accurate temperature monitoring and control in vivo, which can be applied to other biomedical studies.

A Multifaceted Exploration of Atmospheric Turbulence and Its Impact on Optical Systems: Structure Constant Profiles and Astronomical Seeing

This study emphasizes the importance of conducting a comprehensive analysis considering the Cn2 atmospheric parameter for a reliable assessment of the seeing value. It highlights the use of the ECMWF ERA5 model to simulate pressure, temperature, and humidity profiles, enabling the evaluation of optical degradation. Accurate modeling and monitoring of temperature and humidity variables are emphasized for precise data in optical communication and astronomical observations. It also discusses the significance of optical turbulence models in understanding the impact of atmospheric turbulence on optical system performance. The validation of the selected Cn2 models is thoroughly analyzed. To evaluate the impact of the boundary layer on seeing conditions, three factors are considered. First, ERA5 data is used to simulate surface Cn2 values using the PAMELA model. Second, typical Cn2 values for specific dates in Redu are obtained. Finally, the thickness of the boundary layer, denoted as hbl, is calculated. This finding highlights the significant influence of the boundary layer on atmospheric seeing conditions and by incorporating Ibl into the models, a more accurate representation of the effects of the boundary layer on seeing quality is achieved.

Pathways toward precise monitoring and low-carbon sustainability in fruit cold chain logistics: A solution enabled by flexible temperature sensing

Cold chain logistics (CCL) technology plays an irreplaceable role in the supply chain of fresh and perishable fruits. However, the rigidity and inflexibility of traditional temperature sensors limit the accurate monitoring of fruit temperature, resulting in temperature abuse, fruit quality degradation, and excessive energy consumption issues. In this paper, we proposed a flexible temperature sensing solution, which could provide efficient cold chain food quality control and reduce cold chain carbon emissions. The fruit cold chain experiment and temperature field simulation results show that the flexible precise temperature sensing solution can achieve approximately 20 % reduction in refrigeration carbon emissions due to the unique benefit of conformal monitoring. This paper has verified that the precise flexible temperature sensing technology could be combined with the intelligent cold chain control strategies. The energy consumption of refrigeration equipment can be greatly reduced, thereby promoting the development of sustainable and precise cold chain logistics technology.

Optimization of the Monitoring of Coal Spontaneous Combustion Degree Using a Distributed Fiber Optic Temperature Measurement System: Field Application and Evaluation

Coal spontaneous combustion (CSC) in gob not only leads to wasted resources and casualties, but also produces a lot of waste gas that pollutes the underground environment. Mastering the degree of CSC helps ensure that timely and effective control measures are taken. The real-time and accurate monitoring of temperature, as the primary indicator of the extent of CSC, is difficult due to the harsh and hidden environment of gob, resulting in a reduced ability to anticipate and prevent CSC. In this work, a complete distributed optical fiber temperature sensing system (DTSS) set with strong anti-damage ability was developed. The optical cable is protected by internal parallel steel cables and external protective pipes, which greatly improve the system’s reliability and integrity when used in gob. During its application in the Wangyun Coal Mine, an abnormal temperature rise in gob was discovered in time, and the effect of inhibitor spraying was monitored and evaluated. The degree of CSC in the gob was accurately identified, which shows that the work of coal mining can be targeted. This work is expected to improve early warning capability to prevent the risk of CSC in gob, and has promising applications.

Communication performance optimization of coal mine goaf LoRa AD hoc network sensor system based on tree topology

Real-time accurate monitoring of goaf gas, temperature, and other parameters is of key significance for the prevention and control of spontaneous coal combustion in the goaf. In this paper, a tree network and communication protocol for LoRa technology are proposed to solve the problems of small communication coverage and short endurance of the traditional goaf wireless monitoring system. In this paper, a geometric topology structure is designed for wireless sensor nodes to find relay nodes through the path loss model, and an energy-saving optimization algorithm routing scheme is designed. In addition, LoRa AD hoc network experiment platform and upper computer system are developed and designed. Through numerical analysis and experimental results in coal mines, it is proved that the proposed method significantly reduces the energy consumption of the whole network. The coverage radius is increased by 300% compared with the traditional star wireless sensor system, which makes the endurance time and communication quality have higher reliability.

Integrated photothermal agents with fluorescence intensity ratio/lifetime dual-mode temperature sensing

Non-invasive photo-thermal therapy (PTT) has been proposed as a powerful method for cancer treatment, in which accurate temperature monitoring is necessary to prevent ineffective therapy or damage to normal cells during the process of PTT. This promotes the design and development of photothermal agents (PTAs) with real-time temperature control and excellent photothermal conversion. Here, the designed dual-function photothermal agents YVO4: Nd3+, Yb3+@IR-780 were obtained, while the temperature detection behavior based on the fluorescence intensity ratio (FIR) of Nd3+ (4F3/2 → 4I11/2) to Yb3+ (2F5/2 → 2F7/2) and the temperature-dependent Yb3+ lifetime were investigated in detail. The advantages of fluorescence lifetime thermometry in the biological field were confirmed by the internal temperature detection of pork tissue through comparison with fluorescence intensity ratio technology. The photo-thermal conversion efficiency of samples YVO4: Nd3+, Yb3+@IR-780 reached about 34.3% and its potential application was also evaluated by the sterilization of E. coli and S. aureus, which shows that IR-780 coated nano-materials have excellent photo-thermal conversion performance. Results illuminated that the present photothermal agents with temperature self-monitoring had a bright future in the process of photothermal therapy.

A Continuously Worn Dual Temperature Sensor System for Accurate Monitoring of Core Body Temperature from the Ear Canal.

The objective of this work was to develop a temperature sensor system that accurately measures core body temperature from an ear-worn device. Two digital temperature sensors were embedded in a hearing aid shell along the thermal gradient of the ear canal to form a linear heat balance relationship. This relationship was used to determine best fit parameters for estimating body temperature. The predicted body temperatures resulted in intersubject limits of agreement (LOA) of ±0.49 °C over a range of physiologic and ambient temperatures without calibration. The newly developed hearing aid-based temperature sensor system can estimate core body temperature at an accuracy level equal to or better than many devices currently on the market. An accurate, continuously worn, temperature monitoring and tracking device may help provide early detection of illnesses, which could prove especially beneficial during pandemics and in the elderly demographic of hearing aid wearers.

Highly cascaded first-order sapphire optical fiber Bragg gratings fabricated by a femtosecond laser.

This Letter reports an innovative technique for fabricating large-scale, highly cascaded first-order sapphire optical fiber Bragg gratings (FBGs) using a femtosecond laser-assisted point-by-point inscription method. For the first time, to the best of our knowledge, this study successfully demonstrates a distributed array of 10 FBGs within highly multimode sapphire crystal fiber, made possible by employing a high-power laser technique to generate larger reflectors with a Gaussian intensity profile. These first-order FBGs offer advantages such as enhanced reflectivity, shorter fabrication time, and simplified spectral characteristics, making them easier to interpret compared with high-order FBGs. The FBGs' resilience and effectiveness are analyzed by subjecting them to temperature tests, proving their capacity for accurate temperature monitoring up to 1500°C-a testament to their suitability for harsh environments. This novel approach broadens the scope for sensing and communication applications in sapphire fibers, particularly under challenging conditions. The novelty of our work lies in successfully overcoming the limitations of previous designs by integrating a cascade of 10 FBGs in sapphire fibers, thereby enhancing multiplexing capabilities, minimizing overlapping of FBG peaks, and ensuring reliable temperature monitoring in industries and applications with thermal gradients.

Automatic Temperature Detection System at the Entrance

Ensuring public health and safety has grown to be a top priority as a result of the ongoing COVID-19 outbreak. This abstract describes a novel system that makes use of an Arduino Uno, an infrared temperature sensor, an ultrasonic sensor, and a servo motor to automate temperature detection at entry to public places. The central processing unit of the suggested system is an Arduino Uno microcontroller. It is not necessary to make physical touch to monitor body temperature because an infrared temperature sensor is used. The risk of potential contagion is decreased because of this sensor's ability to precisely measure human body temperature at a secure distance. An ultrasonic sensor is added to the system to improve functionality by determining how far away the person is from the door. This maximizes accuracy and efficiency by ensuring that temperature sensing only happens when a person is inside the appropriate range. The system activates the servo motor, which smoothly regulates the movement of a physical barrier, such as a gate or door when it detects a human within the predetermined distance range. Automated access control is made possible by this technology, prohibiting anyone with unusual body temperatures from entering. The system's brain, the Arduino Uno, is responsible for digesting sensor data and producing the right control signals for the servo motor. In the event of an abnormal temperature reading, it can also be configured to sound an alarm or notify authorized persons. The suggested system has several benefits, including accurate distance measurement, contactless operation, and real-time temperature monitoring. To provide efficient screening and stop the transmission of infectious illnesses, it can be applied at a variety of entrance points, including workplaces, educational institutions, medical facilities, and hubs for public transit. The Automatic Temperature Detection System at Entrance, which is demonstrated in this abstract, offers a reliable method for automating temperature screening procedures.

Fiber Bragg Grating Sensor Networks Enhance the In Situ Real-Time Monitoring Capabilities of MLI Thermal Blankets for Space Applications.

The utilization of Fiber Bragg Grating (FBG) sensors in innovative optical sensor networks has displayed remarkable potential in providing precise and dependable thermal measurements in hostile environments on Earth. Multi-Layer Insulation (MLI) blankets serve as critical components of spacecraft and are employed to regulate the temperature of sensitive components by reflecting or absorbing thermal radiation. To enable accurate and continuous monitoring of temperature along the length of the insulative barrier without compromising its flexibility and low weight, FBG sensors can be embedded within the thermal blanket, thereby enabling distributed temperature sensing. This capability can aid in optimizing the thermal regulation of the spacecraft and ensuring the reliable and safe operation of vital components. Furthermore, FBG sensors offer sev eral advantages over traditional temperature sensors, including high sensitivity, immunity to electromagnetic interference, and the ability to operate in harsh environments. These properties make FBG sensors an excellent option for thermal blankets in space applications, where precise temperature regulation is crucial for mission success. Nevertheless, the calibration of temperature sensors in vacuum conditions poses a significant challenge due to the lack of an appropriate calibration reference. Therefore, this paper aimed to investigate innovative solutions for calibrating temperature sensors in vacuum conditions. The proposed solutions have the potential to enhance the accuracy and reliability of temperature measurements in space applications, which can enable engineers to develop more resilient and dependable spacecraft systems.

Advanced Radio Frequency Applicators for Thermal Magnetic Resonance Theranostics of Brain Tumors

Thermal Magnetic Resonance (ThermalMR) is a theranostic concept that combines diagnostic magnetic resonance imaging (MRI) with targeted thermal therapy in the hyperthermia (HT) range using a radiofrequency (RF) applicator in an integrated system. ThermalMR adds a therapeutic dimension to a diagnostic MRI device. Focused, targeted RF heating of deep-seated brain tumors, accurate non-invasive temperature monitoring and high-resolution MRI are specific requirements of ThermalMR that can be addressed with novel concepts in RF applicator design. This work examines hybrid RF applicator arrays combining loop and self-grounded bow-tie (SGBT) dipole antennas for ThermalMR of brain tumors, at magnetic field strengths of 7.0 T, 9.4 T and 10.5 T. These high-density RF arrays improve the feasible transmission channel count, and provide additional degrees of freedom for RF shimming not afforded by using dipole antennas only, for superior thermal therapy and MRI diagnostics. These improvements are especially relevant for ThermalMR theranostics of deep-seated brain tumors because of the small surface area of the head. ThermalMR RF applicators with the hybrid loop+SGBT dipole design outperformed applicators using dipole-only and loop-only designs, with superior MRI performance and targeted RF heating. Array variants with a horse-shoe configuration covering an arc (270°) around the head avoiding the eyes performed better than designs with 360° coverage, with a 1.3 °C higher temperature rise inside the tumor while sparing healthy tissue. Our EMF and temperature simulations performed on a virtual patient with a clinically realistic intracranial tumor provide a technical foundation for implementation of advanced RF applicators tailored for ThermalMR theranostics of brain tumors.

Numerical study on the start-up strategy of cylindrical tubular receiver filled with nickel foam

A cylindrical tubular receiver filled with nickel foam (CTRNF) appears to be a promising receiver concept due to its capability to provide temperatures over 900 °C at a high pressure. Nevertheless, CTRNF is challenged by the unsteadiness and high intensity of radiant flux may cause inaccurate start-up time predictions, providing unrealistic and unstable outlet temperatures. In this article, these matters are addressed by a numerical model coupling the Monte Carlo ray tracing (MCRT) method and discrete coordinate (DO) radiative transfer model. The model considers the cold, semi-cold, semi-hot, and hot start-up strategies on the CTRNF using N2 and Ar as the working medium. Three preheating methods and their influence on the thermal characteristic of the CTRNF are proposed. Temperature and equivalent stress distribution of internal heat absorber is simulated and analyzed. The results indicate that the duration for four start-up strategies takes 1711 s, 2189 s, 1212 s and 1032 s as the outlet temperature reaches to 1200 K, respectively, when Ar is used as the working medium (10 g/s) and radiative power of 10.5 kW incidents on the solar receiver. Compared with the 68.44 kg Ar consumption of cold start-up strategy, the Ar working medium consumption decrease by 24.44 kg, 51.68 kg, and 63.16 kg for semi-cold start-up, semi-hot start-up, and hot start-up strategy. However, the maximum equivalent stress of the CTRNF under the hot start-up strategy is 100 MPa higher than under the cold start-up strategy, which requires accurate monitoring of the cavity temperature in solar receiver.