Temperature Monitoring Research Articles

Ultra-Thin Highly Sensitive Electronic Skin for Temperature Monitoring.

Electronic skin capable of reliable monitoring of human skin temperature is crucial for the advancement of non-invasive clinical biomonitoring, disease diagnosis, and health surveillance. Ultra-thin temperature sensors, with excellent mechanical flexibility and robustness, can conformably adhere to uneven skin surfaces, making them ideal candidates. However, achieving high sensitivity often demands sacrificing flexibility, rendering the development of temperature sensors combining both qualities a challenging task. In this study, we utilized a low-cost drop-casting technique to print ultra-thin and lightweight (thickness: approximately 3 µm, weight: 0.61 mg) temperature sensors based on a combination of vanadium dioxide and PEDOT:PSS at room temperature and atmospheric conditions. These sensors exhibit high sensitivity (temperature coefficient of resistance: -5.11%/°C), rapid response and recovery times (0.36 s), and high-temperature accuracy (0.031 °C). Furthermore, they showcased remarkable durability in extreme bending conditions (bending radius = 400 µm), along with stable electrical performance over approximately 2400 bending cycles. This work offers a low-cost, simple, and scalable method for manufacturing ultra-thin and lightweight electronic skins for temperature monitoring, which seamlessly integrate exceptional temperature-measuring capabilities with optimal flexibility.

Real‐time reliability evaluation method for IGBT module in MMC based on junction temperature and bond wire failure online monitoring

AbstractThe lack of an MMC reliability evaluation approach that incorporates data on essential components' health monitoring in the already related research prevents reliability from being further improved. Therefore, this article proposes a real‐time reliability evaluation method of the multi‐state IGBT module in MMC through iterative calculation of the Markov chain model. The degradation process of the IGBT module is divided into multiple states based on the monitored bond wire failure, and the failure rate of the IGBT module is updated in real time using the accumulated monitoring data of junction temperature. The proposed method can more accurately reflect the real state of MMC compared with the binary state evaluation method. Besides, a multi‐channel high‐speed data acquisition board is designed to measuring the gate voltage and collector voltage of the IGBT for the health evaluation of IGBT modules in MMC; the typically measured results validate the effectiveness of the data acquisition board.

Wide-range and ultra-low temperature thermometer based on a silicon resonator.

In this Letter, the silicon-based microring resonator (MRR) was experimentally demonstrated for cryogenic sensing down to 10 K by overcoming the issue of acquiring the optical signals at low temperatures for on-chip optical sensors. A wide-range temperature sensor from 240 to 10 K was obtained. The experimental results show that the device sensitivity decreased from 64.7 pm/K at 240 K to 4.19 pm/K at 10 K. Theoretical analysis indicates that the reduction in sensitivity is attributed to the weakening of thermo-optic effects with the decrease in temperature, which is well consistent with the experimental results. Based on this work, the silicon-based ring resonators, featuring complementary metal oxide semiconductor (CMOS) compatibility, high-quality factors, and ease of chip-scale integration, are a potential platform for ultra-low temperature monitoring.

Innovation for recycling of organic matter through composter with automatic and sustainable temperature recording accessed via Bluetooth/mobile app.

Compost reactors, commonly used in experiments, industrial assays, and home residue treatment systems, have the potential to facilitate composting. Challenges persist in the realm of small-scale composting, encompassing facets such as temperature monitoring, homogenization of the compost mass, management of moisture with the control of leachate generation, and integration with a renewable energy source. This study assesses a pioneering composter prototype endowed with essential features to ensure a pragmatic and secure composting process. This includes the facilitation of remote access to temperature data via Bluetooth and a mobile application. Across successive trials, the scrutinized composter prototype consistently yielded reproducible outcomes, exhibiting a coefficient of variation below 25% for the majority of appraised parameters. In comparison to a conventional reactor, the decomposing residue mixture within the examined prototype manifested elevated temperatures (p < 0.05). Moreover, the tested prototype demonstrated C/N ratio lower than 20/1 within 45days, a higher final nitrogen concentration, and enhanced germination of seeds that served as phytotoxicity bioindicators. Notably, the prototype needed 46.6% less space, offering improved leachate control, three times faster turning time, temperature monitoring, and reduced fly attraction.

Heat and mass transfer during conductive drying of washing phosphate sludge

This study investigates the influence of drying temperature on the conductive drying behavior of washing phosphate sludge. A mathematical model, based on Fourier's Fick diffusion law and the heat transfer equation, was developed to simulate coupled heat and mass transfer during the drying process, incorporating the shrinkage effect. The sludge samples, obtained from the Khouribga phosphate plant in Morocco, were subjected to drying at temperatures of 70°C and 95°C. The experimental setup included continuous monitoring of temperature, humidity, and mass loss throughout the process. COMSOL Multiphysics software was used to solve the nonlinear equations governing heat and mass transfer. Results indicate that increasing the drying temperature significantly accelerates the drying rate. The model successfully predicts the moisture content and temperature distribution over time, aligning well with experimental data. Statistical validation, using the determination coefficient (R²) and root mean square error (RMSE), confirms that the model accurately describes the drying behavior, with R² values of 0.9957 and 0.9967 at 70°C and 95°C, respectively. The inclusion of the shrinkage effect enhances the model's precision in describing the drying kinetics under varying conditions.

Surveillance of esophageal injury after atrial fibrillation catheter ablation.

Atrial-esophageal fistula following ablation procedures for atrial fibrillation (AF) remains a major concern. There is no standardized approach to minimize the risk and morbidity of this serious complication. The objective of this study was to present the 7-year experience of systematic endoscopic surveillance of esophageal injury after AF catheter ablation. This was a retrospective single-center registry of systematic endoscopic evaluations after consecutive AF ablation procedures performed from 2016 to 2022. A total of 677 AF ablation procedures with controlled esophagogastroduodenoscopy (EGD) were analyzed during that period. Most patients were male (71%) with paroxysmal AF (71%). Radiofrequency with electroanatomical mapping was the main ablation approach for 633 patients (93.5%). Esophageal temperature monitoring was performed using a single sensor in 220 patients (34.3%) and a multisensor probe in 296 patients (46%). Most of the patients presented no esophageal lesions (75,7%). Severe lesions (Kansas-city-classification KCC 2B) were found in 46 (6.8%) of them, requiring a new EGD in 7days. KCC2B lesions were persistent in 3 patients, 2 of whom had ulcers during healing and 1 patient with a deep ulcer of 10mm who was admitted to the hospital and underwent fasting and parenteral nutrition. The ulcer healed in the second week after the procedure. Both esophageal temperature monitoring strategies were equivalent at preventing thermal lesions. Additionally, a greater left atrium (LA) was associated with a lower incidence of esophageal ulcer (P = 0.028). Most of the lesions spontaneously healed. The incidence of esophageal injury after ablation was 24.3%. Most (72%) were mild lesions that required no therapeutic intervention. A larger left atrium (LA) was correlated with a lower incidence of thermal lesions. Early endoscopy can help diagnose severe esophageal lesions and may provide additional information for the surveillance of esophageal injury after AF ablation.

A method of attaining optical fibre pre-compression for strain and temperature monitoring inside metal at extremely high temperatures

A metal-embedded fibre sensor's highest operational temperature is limited by strain due to differential thermal expansion between fibre material silica and the host metal. For a stainless steel 316 or nickel-embedded fibre sensor, it is approximately 500°C because, above this temperature, thermal strain from the host metal exceeds the tensile strength of the fibre. A novel method of attaining optical fibre sensor pre-compression inside metal for compensating the external thermal strain and achieving strain and temperature monitoring inside metal up to at least 800°C is demonstrated in this paper. The sensor shows good repeatability (error within 10°C) for the twelve temperature cycling experiments carried out after pre-compressing the fibre. Sensor response at different temperatures and external thermal strain shows good long-term stability. The highest operational temperature is limited by the fibre sensing structure (fibre Bragg grating) used in this study; using a distributed sensing interrogator can extend the operational temperature to the limits of optical fibre material with the method demonstrated in this paper.

Development of an implantable sensor system for in vivo strain, temperature, and pH monitoring: comparative evaluation of titanium and resorbable magnesium plates

Biodegradable magnesium is a highly desired material for fracture fixation implants because of its good mechanical properties and ability to completely dissolve in the body over time, eliminating the need for a secondary surgery to remove the implant. Despite extensive research on these materials, there remains a dearth of information regarding critical factors that affect implant performance in clinical applications, such as the in vivo pH and mechanical loading conditions. We developed a measurement system with implantable strain, temperature, pH and motion sensors to characterize magnesium and titanium plates, fixating bilateral zygomatic arch osteotomies in three Swiss alpine sheep for eight weeks. pH 1–2 mm above titanium plates was 6.6 ± 0.4, while for magnesium plates it was slightly elevated to 7.4 ± 0.8. Strains on magnesium plates were higher than on titanium plates, possibly due to the lower Young's modulus of magnesium. One magnesium plate experienced excessive loading, which led to plate failure within 31 h. This is, to our knowledge, the first in vivo strain, temperature, and pH data recorded for magnesium implants used for fracture fixation. These results provide insight into magnesium degradation and its influence on the in vivo environment, and may help to improve material and implant design for future clinical applications.

Utilization of Tea Polyphenols as Color Developers in Reversible Thermochromic Dyes for Thermosensitive Color Change and Enhanced Functionality of Polyester Fabrics

Thermochromic textiles possess the capability to indicate ambient temperature through color changes, enabling real-time temperature monitoring and providing temperature warnings for body heat management. In this study, three thermochromic dyes—blue, red, and yellow—were synthesized using crystalline violet lactone (CVL), 6′-(diethylamino)-1′,3′-dimethyl-fluoran (DDF), and 3′,6′-dimethoxyfluoran (DOF) as leuco dyes, respectively, with biomass tea polyphenol serving as the color developer and tetradecanol as the phase change material. The chemical structures of these dyes were characterized using UV spectroscopy, infrared spectroscopy, Raman spectroscopy and 1H NMR. The thermochromic mechanisms were investigated, revealing that the binding bonds between the leuco dyes and the color developer broke and reorganized with temperature changes, imparting reversible thermochromic property. Polyester fabrics were dyed using an impregnation method to produce three reversible thermochromic fabrics in blue, red, and yellow. The structure and properties of these fabrics were analyzed, showing a significant increase in the UPF value from 26.3 to approximately 100, indicating enhanced UV resistance. Water contact angle measurements revealed that the contact angle of undyed polyester fabrics was 139°, while that of dyed polyester fabrics decreased by about 40°, indicating improved hydrophilicity. Additionally, the fabric inductive static tester showed that the static voltage half-life of dyed polyester fabric was less than 1 s, demonstrating a significant antistatic effect. Infrared thermal imaging results indicated that during the warming and cooling process, the thermochromic polyester fabric exhibited specific energy storage and insulation effects at 38 °C, close to the human body temperature. This study presented a novel approach to developing smart color-changing textiles using biomass-derived thermochromic dyes, offering diverse materials for personal thermal management, and intelligent insulation applications.

Lanthanide-Doped Nanoparticles Anchoring on Metal-Organic Frameworks with Thermally Enhanced Upconversion Luminescence for Sensitive Nanothermometers.

Nanothermometers can detect changes in the local temperature in living cells and in vivo, revealing fundamental biological properties. Despite the exploration of different temperature-responsive materials, the design and development of temperature-sensing probes with high brightness and high sensitivity remain a daunting challenge. Here, we employed the UiO-66 type metal-organic frameworks (MOFs) to anchor UNCPs on the surface of the MOFs for constructing MOF@UCNPs nanohybrids. The in situ composite method with MOFs leads to the coordination interaction between the ligands and the surface of UCNPs, enabling controlled composite formation between different MOFs and UCNPs. Remarkably, the surface interaction favors the anomalous thermo-enhanced luminescence, achieving a 35-fold enhancement of UiO-66@NaYF4:Yb/Tm at 413 K. Furthermore, these MOF@UCNPs nanohybrids with thermo-enhanced luminescence are developed as multifunctional biological probes for bioimaging and intracellular temperature sensing, demonstrating a high thermal sensitivity of 1.92% K-1 in the physiological temperature range. Based on these findings, temperature monitoring of the local position was successfully carried out by the designed MOF@UCNPs nanoprobes in vivo. These findings underscore the potential of MOF@UCNPs nanohybrids, opening up new avenues for the development of a multifunctional platform for biological analysis.

Porous and Conductive Fiber Woven Textile for Multi‐Functional Protection, Personal Warmth, and Intelligent Motion/Temperature Perception

AbstractIndustrialization and human activities have introduced numerous hazards, including exposure to harsh chemicals, radiation, static electricity, and fire risks, particularly in high‐risk sectors such as engineering, rescue operations, military, and aerospace. This study presents a multi‐functional protective textile developed from a conductive fiber composed of polytetrafluoroethylene (PTFE) and carbon nanotubes (CNT), crucial for ensuring personal safety. The conductive fiber demonstrates remarkable strength (17.3 MPa), high porosity (76%), and significant electrical conductivity (185 S m−1), coupled with excellent fineness and flexibility due to its dual‐nanofibrous structure. The resulting textile exhibits exceptional hydrophobicity, chemical resistance, and high electromagnetic interference shielding effectiveness (29 dB in the X‐band), alongside a superior UV protective factor (&gt;3000) and anti‐static properties. Notably, it possesses outstanding electro/photo thermal conversion capabilities, enabling consistent heat generation for personal warmth. Additionally, the textile responds electrically to deformation and temperature changes, facilitating intelligent applications such as motion and temperature monitoring and fire alerts. This work offers a novel strategy for fabricating PTFE‐based composite fibers with porous microstructures and high electrical conductivity, setting a new standard for next‐generation protective clothing with advanced functionalities.

A wearable, self-sustainable, and wireless plantar pressure and temperature monitoring system for foot ulceration prognosis and rehabilitation

Continuous foot temperature and pressure monitoring are desirable for prevention and care of foot health conditions such as Diabetic foot ulceration (DFU). However, monitoring these parameters simultaneously is complex, and mostly rely on sensors with undisrupted power supply integration. Herein, we propose high-performance self-sustainable smart footwear capable of monitoring foot pressure and temperature at various locations for real-time applications. The footwear consists of three modules of an integrated electromagnetic generator (EMG) and triboelectric (TENG) self-powered pressure sensors operated by very elastic 3D printed thermoplastic polyurethane (TPU) springs formed by stacking circular plates that allow TENG pressure sensors to be embedded within. Additionally, Laser-induced graphene (LIG) temperature sensors are used for monitoring foot temperature. The embedded EMG can deliver high output power during various activities: walking (38 mW), running (154 mW), and jumping (75 mW), sufficient to power signal processing and transmission circuitries for wireless monitoring of foot temperature and pressure. TENG-based pressure sensors and LIG temperature sensors (LTS) embedded in this design allow mapping of foot pressure (0.2 V/kPa at 1 Hz) and foot temperature (0.55 Ω °C−1) continuously. Finally, footwear was assembled successfully to demonstrate wireless self-sustainable multisensory smart footwear for monitoring foot pressure and temperature to prevent and rehabilitate diabetic foot ulcers.

High-Strength PVA/Cellulosic hydrogels with Acid/Base and thermo dual-responsive fluorescence

Fluorescent polymer hydrogels (FPHs) with tunable luminous features have attracted immense interest. Nevertheless, until now, the development of most FPHs had been hindered by their poor mechanical properties and limited application range. This study presents a novel strategy to fabricate high-strength, multi-application cellulosic fluorescent hydrogels using polyvinyl alcohol (PVA) and fluorescent nanocellulose (containing pyrene tetracarboxylic acid) through a salting-out process. Such strategy enables cellulosic hydrogels with high tensile strength and toughness (26.45 MPa and 201.27 MJ/m3), compressive strength (165.58 MPa), dual-responsive fluorescence (acid/base and temperature), and multiple applications. Specifically, cellulosic hydrogels exhibit fluorescence switching through the utilization of lanthanide metals (Eu3+/Tb3+), acid/base, and temperature, owing to the presence of perylene tetracarboxylic acid as a fluorescent moiety with an aggregation-caused quenching (ACQ) effect. Based on this, the resulting hydrogels were utilized in rewritable display systems, temperature monitoring, and encrypted QR codes. This study envisions opening new possibilities for the development of high-strength fluorescent hydrogels with multiple applications.

Evidence-based strategies for optimizing long-term temperature monitoring in offices

Long-term monitoring of the thermal environment in office buildings has become increasingly relevant with the rise of wireless sensor networks. However, there is a notable absence of explicit guidelines for implementing monitoring strategies in such contexts. This lack of direction can lead to inconsistent deployment of sensor networks, resulting in higher maintenance costs and inaccurate long-term assessments of thermal conditions. Based on data analyses of high-accuracy, high-frequency field measurements conducted over a year or longer across multiple offices in Sydney and Shanghai, this study proposes a strategy for long-term temperature monitoring. The strategy advises practitioners to prioritize considerations such as air-conditioning type, room size, and space function when selecting "representative" sensor locations. Typically, sampling every 30 min is deemed adequate for shared offices where an error margin of ±0.5°C is acceptable. For environments with stable indoor temperatures, less frequent sampling intervals suffice. A power regression model tailored for offices equipped with central AC and no operable windows was developed to predict the maximum allowable sampling interval based on several days of indoor temperature monitoring in winter. Regarding monitoring duration, the study advocates a preferred sampling period of one year to comprehensively capture seasonal variations. Alternatively, a minimum monitoring period of four to six months commencing in late spring or early summer is identified as potentially sufficient. These findings offer valuable insights for optimizing long-term thermal monitoring practices in offices and may contribute to expanding the scope of thermal comfort standards.

Internet of things enabled rail-wheel contact temperature monitoring using fiber Bragg grating sensors

Internet of things enabled rail-wheel contact temperature monitoring using fiber Bragg grating sensors

Development of a silicon carbide radiation detection system and experimentation of the system performance

Silicon carbide (SiC) detectors have excellent radiation detection capabilities for various radiation particles, including high energy resolution, fast response times, and good radiation resistance. A SiC radiation detection system was developed to measure the neutron fluence rate and the γ-ray dose rate in high intensity radiation fields. The system was composed of two SiC detectors, a temperature monitor, two preamplifiers for each SiC detector, a data acquisition unit with two signal channels, three pairs of communication devices, and an application software to analyze and visualize the measurement data. The two SiC detectors were fabricated based on two kinds of 4H-SiC diodes and used to respectively respond to neutrons and γ-rays. Repeated experiments showed that the two SiC detectors of the system can respond to α-particles, neutrons, and γ-rays. To verify the performance of the SiC detection system, including the response linearity of the neutron fluence rate, the measurement range of the γ-ray dose rate, and the radiation resistance of the SiC radiation detectors, the system was tested in multiple neutron and γ-ray fields. The tests results show the system can measure the neutron fluence rate from 5.64 × 10 2 cm−2 s−1 to 1.03 × 10 5 cm−2 s−1 with excellent linearity response, and the γ-ray dose rate from 0.005 Gy/h to 20 Gy/h. Furthermore, the SiC detectors demonstrated good radiation resistance. The neutron and γ-ray radiation field can still be measured stably by the system after exposure to neutron fluence of 1.07 × 10 14 cm−2 and γ-ray dose of 3.52 × 10 4 Gy. This work is the preliminary research to continue the exploration how to measure the n/γ hybrid fields accurately using SiC detectors considering the different energy of neutrons.

Validating a Pneumatic Tube System for Blood Product Delivery

Abstract Introduction/Objective Timely delivery of blood products can be of utmost importance to providing quality care. We aimed to validate the use of a high-speed pneumatic tube system (PTS) that was already installed at our hospital. By reducing delivery times, patient resuscitation and survivability can be increased. Methods/Case Report We followed the Association for the Advancement of Blood &amp; Biotherapies (AABB) guidelines to validate a PTS in a large tertiary academic medical center. The requirements include: verifying product suitability, ensuring product integrity, temperature monitoring, transportation time measurements, and proper packaging and tracking of product receipt. We validated the transfer of packed red blood cells (PRBC), plasma, platelets, and cryoprecipitate from the central blood transfusion services lab (BTS) to nursing stations in a separate building up to 1500 feet (&amp;gt;1/4 mile) away using a Swisslog Translogic® PTS Inclusion with foam inside the PTS carriers helped reduce bumps during transit and insulated products from heat. Results (if a Case Study enter NA) The mean temperature of the PRBC was 6.6 degrees Celsius and none exceeded the AABB maximum of 10 degrees Celsius. The mean time for blood products transit to the nursing stations was 3 minutes (m) and 33 seconds (s). The median time was 3m 31s, and it ranged from 2m 18s to 5m 38s. The PTS reduced delivery times of blood products by up to 10-12 minutes compared to manual porters. Conclusion Transporting blood products via PTS is an efficient method that reduces the required manpower and leads to better utilization of resources. However, it is essential to validate the PTS system before implementing it operationally.

Climate-induced risk assessment of the quarantine room in a University Library

Microclimate conditions in conservation spaces such as museums, galleries, storages, archives, and libraries significantly impact the preservation of cultural materials, potentially leading to permanent damage. This study focuses on quarantine rooms, essential for isolating and inspecting incoming collections for infestations or contamination. Despite their importance, systematic microclimate investigations in such spaces have not been conducted until now. In this research, temperature and relative humidity monitoring has been conducted over the past 3 years (i.e., 2021-2022-2023) within the quarantine room of the Norwegian University of Science and Technology (NTNU) University Library (located within the DORA I concrete bunker, Trondheim, Norway). Data analysis revealed stable indoor conditions due to the buffering capacity of the massive building envelope together with climate control system. Specific metrics for the estimation of climate-induced chemical and biological risks on vulnerable artifacts were applied to compute the percentage of time for which thermohygrometric conditions could favour cellulose hydrolysis and biodeteriogens proliferation on a yearly basis. In this way, the study provided a decision-making tool useful to evaluate the best time (in terms of safest temperature and relative humidity conditions) when to introduce incoming collections into the quarantine room, depending on the material they are made of and on the timeframe selected for their isolation.

Volumetric lesion analysis and validation of various bipolar configurations in radiofrequency ablation of ventricular myocardium in a bovine model.

The bipolar radiofrequency ablation(B-RFA) strategy was increasingly used to target deep intramural re-entrant foci responsible for the arrhythmia not ablated by conventional unipolar RFA / sequential unipolar RFA. Lesional characteristics of various bipolar configurations were largely unknown. To investigate the lesional geometry in relation to various factors to determine the most effective ablation strategy that minimises steam pops and achieves transmurality. To assess the temperatures at the return electrode. A custom-made validated ex-vivo bipolar ablation model was used to assess lesion formation. The myocardial sample was placed between two ablation catheters in four different orientations. Lesions were created using different power (30W, 40W, 50W) and time settings(30, 40 and 50s) with different catheter orientations. Data was analysed using binary logistic regression and multiple linear regression. Among 107 lesions, The volume of the active catheter lesion (266 +/- 137mm^3) significantly differed from their return electrode counterparts (130 +/- 91.8mm^3) (p < 0.001), and the temperatures at the return electrode end were lower than at the active electrode (p = 0.004). Higher power and longer duration application led to more frequent steam pops (p < 0.001), while true parallel configuration resulted in fewer steam pops (p < 0.001). A custom model without ground electrode temperature monitoring is safe and cost-effective. The safest strategy is a true parallel configuration with an inter-electrode distance of at least 15mm and a power of 30W to 40W, which generates lower steam pops and better transmurality.

A three-mode optical thermometer utilizing Cs2NaInCl6: Sb3+/Tb3+ lead-free double perovskite microcrystals for lubricating oil temperature monitoring

Temperature monitoring is essential to maintain proper diesel engine lubricating oil temperature and ensure safe navigation for ships. In contrast to conventional contact thermometers, optical thermometers that operate without physical contact have garnered researchers' attention because of their rapid response, exceptional sensitivity, and capability to measure microscopic objects. Combining multiple thermometric techniques enables self-referenced temperature sensing, thereby improving the accuracy of temperature monitoring signals. Herein, Cs2NaInCl6: Sb3+/Tb3+ microcrystals (MCs) were synthesized to investigate the optical properties and multi-mode temperature detection performances. Upon excitation of 320 nm, energy transfer (self-trapped excitons (STEs)→Tb3+) occurs, resulting in blue emission from the STEs and the characteristic emissions from Tb3+. Owing to the superior luminescent properties of Cs2NaInCl6:Sb3+/Tb3+ that vary with temperature, a three-mode optical thermometer has been developed using the ratio of fluorescence intensities (FIR) of STEs and Tb3+ emissions, CIE color coordinates, and the fluorescence lifetime of Tb3+. The reliability of the thermometer has been proven through the practical application of lubricating oil temperature detection, and the measured temperatures closely align with those obtained via infrared thermometry. This work represents a significant step towards developing multi-mode thermometers based on lead-free perovskites.