Temperature Research Articles

Intensity and volume of physical exercise influence DOMS and skin temperature differently in healthy adults

It remains unclear whether exercises leading to different outcomes of delayed onset muscle soreness (DOMS) may also elicit different skin temperature responses. The aim of this study was to determine whether different intensities and volumes of a single-joint exercise influence the DOMS and skin temperature measurements differently in healthy adults. Thirty-nine men and women were randomly assigned to three groups performing different exercise of different intensities and volumes (Exhaustion, Fatigue, Submaximal) to induce DOMS in the biceps brachii. DOMS (numeric pain rate scale, NPRS), pressure pain threshold (PPT) and skin temperature (infrared thermography, IRT) were measured on exercise day and 48 h later. The different exercises resulted in lower PPT responses 48 h after exercise and different DOMS reported across the different groups. Skin temperature outcomes did not differ following the different protocols. We found an increased minimum skin temperature 48 h after exercise in groups performing more intense exercises, but such differences were found in both exercised and non-exercised arms. Differently of PPT outcomes, pain reported depended on exercise intensity, and skin temperature 48 h after exercise could not show acute exercise adaptations. Skin temperature responses are contingent upon the characteristics of the participants rather than exercise intensity.

In situ calorimetric temperature measurements of Cu, Cr, Ti targets during DC magnetron sputtering

Direct measurements of the temperature of Cu, Ti, and Cr targets (3 mm thick, Ø 55 mm) using thermocouples attached to the front (erosion zone) and back sides of the targets during magnetron sputtering (DC) were performed. The variables are the target mode (cooled or uncooled target), working gas (Ar, N2), and discharge power density (qin). It was shown that the target temperature reaches ∼730 K on the front and ∼530 K on the back sides of the cooled target, while for an uncooled one, it is ∼1050 and 950 K, respectively (Cu target). For both modes and all targets, the target temperature is slightly higher when sputtering in N2. Calculations of the surface temperature based on measurements of the target temperature and its emissivity showed that for all targets, their surface temperature is significantly higher compared to the bulk of the target. Based on the temperature measurements on opposite sides of the Cu target, its dynamic thermal conductivity is calculated. It turned out that it is ∼100 times lower than the thermal conductivity of normal Cu. The above results are discussed based on a physical model that assumes the appearance and existence during sputtering on the target surface of a layer whose properties strongly differ from those of ordinary metals.

Pure rotational Raman lidar for accurate profiling of atmospheric temperature and aerosol/cloud backscatter coefficients

We have created a pure rotational Raman (PRR) lidar for round-the-clock and large-height-range quantitatively-physical measurements of atmospheric temperature profiles. A seeded frequency-doubled Nd:YAG laser is utilized as the light source. It has a typical power of ∼18 W and a pulse repetition rate of 30 Hz. The lidar uses a 0.3-m-diameter receiver and a 1.0-m-diameter receiver together. Each receiver contains a state-of-the-art three-channel polychromator that extracts respectively two individual Stokes N2 PRR lines with rotational quantum numbers J = 4 and 14, as well as a Rayleigh/Mie backscatter signal. The temperature profiles are derived from the strict analytical expression of temperature in terms of the ratio of the two PRR line signals without calibration. Furthermore, a strict analytical expression has been established to derive the aerosol/cloud backscatter coefficient profiles without assumptions on the lidar ratio. The lidar provides a rigorous and effective methodology for accurate profile measurements of the atmospheric temperature and optical properties of aerosol/cloud. Observational examples and statistics obtained at a subtropical site have demonstrated the high measurement accuracies, large measurement altitude range, good range/time resolution, and unprecedented daytime measurement capability of this single-line-extracted PRR lidar.

Lead Sulfide Quantum Dots as the Semiconductor Layer in Thin-Film Phototransistors for Infrared Thermal Image Sensing

Abstract This paper utilizes lead sulfide quantum dots, known for their high absorption coefficients, ease of solution processing, and high stability in air, as the semiconductor layer in thin-film phototransistors. These are combined with the most mature glass panel processing technology to create an infrared sensing device characterized by simple manufacturing processes, low production costs, small sensing areas, and large-area sensing capabilities. The novel lead sulfide quantum dot infrared sensing device proposed here exhibits remarkable performance at room temperature and under uncooled operation. It demonstrates a temperature sensitivity above 300oC for radiation temperature measurement, a fast total response time of 69 µs, and performance metrics such as noise of 1.9×10-12 A/Hz1/2, a maximum responsivity of 103 A/W, and a maximum detectivity of 2.04×1013 Jones. Therefore, the experimental results obtained here are significant for the research and design of future advanced quantum dot-based thermal imaging sensing applications.

Study on Ice Temperature Fields and Borehole Closure Rates During Thermal Ice Drilling

Thermal ice drilling technology is extensively used in drilling operations such as temperature measurement holes and subglacial water environment investigations in Antarctica owing to its advantages of compactness, light weight, and ease of operation. However, thermal drilling disturbs the initial temperature of the surrounding ice, making it impossible to obtain the true ice temperature through a borehole within a short period. Meltwater refreezing also causes the borehole to shrink and close, posing a threat to drilling safety. Therefore, obtaining an accurate characterization of the temperature field around the hole and assessing the meltwater refreezing rate are crucial for determining the appropriate temperature measurement duration and optimizing drilling parameters. To address this issue, a temperature measurement platform for the ice surrounding the borehole was developed. Experimental investigations were conducted to analyze the temperature fields during thermal drilling using both small-diameter thermal heads and RECoverable Autonomous Sonde (RECAS) thermal heads. This study clarifies the temperature field changes in the surrounding ice during and after thermal drilling. It also elucidates the effects of parameters such as the ice temperature, thermal head heating power, and thermal head diameter on the temperature field around the hole and estimates the meltwater refreezing rate inside the borehole. The results indicated that the temperature of the surrounding ice peaked approximately 5–7 h after drilling and subsequently decreased and returned to the original temperature within 48 h. The thermal disturbance radius in the surrounding ice was approximately 1.1 to 1.7 times the borehole radius when the thermal head passed through. However, after the thermal head passed, the thermal disturbance radius continued to expand owing to the heat released from meltwater refreezing, reaching 9.7 to 12.5 times the borehole radius. The average meltwater refreezing rate, estimated from temperature measurement tests at −16 °C, was 3.6 mm/h.

Tailoring magnetic properties of CoFeB films via tungsten buffer and capping layers

Controlling the interface between W and CoFeB-based buffer or capping layers at an appropriate temperature is essential for modifying the strength of magnetic anisotropy. In this work, we systematically explore the impact of W buffer and capping layers on the structural, topological, and magnetic anisotropy properties of W (5 nm)/CoFeB(10 nm) and CoFeB(10 nm)/W(3 nm) bilayers sputtered at room temperature (RT) and annealed at an optimal annealing temperature (TA) of 400 °C. Our findings demonstrate that the bilayer films’ uniaxial magnetic anisotropy (UMA) with out-of-plane coercivity (Hc⊥) is highly influenced by the W buffer, capping layers, and TA. Specifically, the Hc⊥ of the CoFeB layer with the buffer and capping layers annealed at 400 °C samples exceed several times the coercivity of those unannealed. CoFeB buffered with W and annealed at 400 °C shows larger Hc⊥, two-fold UMA, and higher in-plane UMA energy density (Keff) than the CoFeB/W bilayers, which can be attributed to the W buffer layer inducing the crystallization of CoFeB during annealing. The W buffer, capping layers, and the TA for W and CoFeB-based bilayer samples significantly alter the surface morphology, grain sizes, and surface roughness. The XRD analysis reveals nano-crystallites embedded in the larger grains of the 400 °C annealed samples. Hence, this work offers a promising approach to achieving high thermal stability of UMA in W and CoFeB-based spintronic applications.

Investigation of vapor liquid equilibria for HFO-1336mzz(E) + HFC-1234ze(E) binary system by a novel developed cyclic-analytical apparatus

Hydrofluoroolefins (HFOs), which have excellent thermophysical properties and environmental performance, are considered as the most promising environmentally friendly alternatives to the currently used refrigerants. The vapor-liquid equilibrium (VLE) properties of fluids are the basis for the design and optimization of chemical separation and refrigeration systems. In this work, a high-precision and visual VLE experimental apparatus was developed based on the cyclic-analytical method. which mainly includes thermostatic bath, VLE cell, temperature and pressure measurement system, and gas chromatograph, etc. The expanded uncertainties of temperature, pressure, and composition measurement are 0.06 K, 0.0086 MPa, and 0.056 mole fraction, respectively. By measuring the VLE data of the known binary system and comparing it with the literature, the reliability and accuracy of the experimental apparatus were verified. The VLE data of HFO-1336mzz(E) + HFC-1234ze(E) were measured in the temperature range of 293.15 to 358.15 K. The experimental data were correlated with the Peng Robinson (PR) equation of state (EoS) combined with Mathias-Copeman alpha function (MC) and van der Waals (vdW) mixing rule (PRMC-vdW model) in order to adjust the binary interaction parameters (BIP). The VLE data was also compared with the PPR78 predictive model. The VLE investigation provides a basis for further research on the cycle performance of the mixed working fluid.

Development of an atmospheric boundary layer detection system based on a rotary-wing unmanned aerial vehicle.

To enhance meteorological detection methods, an atmospheric boundary layer detection system based on a rotary-wing unmanned aerial vehicle (UAV) was proposed. Computational fluid dynamics (CFD) was employed to model the surrounding airflow distribution during UAV hovering, thereby determining the optimal positions for sensor installation. A novel radiation shield was designed for the temperature sensor, offering both excellent radiation shielding and superior ventilation. To further improve temperature measurement accuracy, an error correction model based on CFD and neural network algorithms was designed. CFD was used to quantify the temperature measurement errors of the sensor under different environmental conditions. Subsequently, random forest and multilayer perceptron algorithms were employed to train and learn from the simulated temperature errors, resulting in the development of the error correction model. To validate the accuracy of the detection system, comparative experiments were conducted using the measurement values from the 076B temperature observation instrument as a reference. The experimental results indicate that the mean absolute error, root mean square error, and correlation coefficient between the experimental temperature errors and the algorithm-predicted errors are 0.055, 0.066, and 0.971 °C, respectively. The average error of the corrected temperature data is 0.05 °C, which shows substantial agreement with the reference temperature data. During UAV hovering, the average discrepancies between the temperature, humidity, and air pressure data of the detection system and the ground-based reference data are 0.6 °C, 1.6% RH, and 0.77 hPa, respectively.

High Pressure Melting Curve of Fe-Si: Implication for the Thermal Properties in Mercury's Core.

The motion of liquid iron (Fe) alloy materials in the outer core drives the dynamo, which generates Mercury's magnetic field. The assessment of core models requires laboratory measurements of the melting temperature of Fe alloys at high pressure. Here, we experimentally determined the melting curve of Fe9wt%Si and Fe17wt%Si up to 17GPa using in situ and ex situ measurements of intermetallic fast diffusion that serves as the melting criterion in a large-volume press. Our determined melting slopes are comparable with previous studies up to about 17GPa. However, when extrapolated, our melting slopes significantly deviate from previous studies at higher pressures. For Mercury's core with a model composition of Fe9wt%Si, the melting temperature-depth profile determined in our study is lower by ∼150-250K when compared with theoretical calculations. Using the new melting curve of Fe9wt%Si and the electrical resistivity values from a previous study of Fe8.5wt%Si, we estimate that the electronic thermal conductivity of liquid Fe9wt%Si is 30 Wm-1K-1 at the Mercury's CMB pressure of 5GPa and 37Wm-1K-1 at an assumed ICB of 21GPa, corresponding to heat flux values of 23mWm-2 and 32mWm-2, respectively. These values provide new constraints on the core models.

Comparative Analysis of Cryotherapy Modalities Using Muscle Tissue Temperature Measurement: Cold Pack, Cold Compression, and Hyperbaric Gaseous Cryotherapy

Cryotherapy is widely used in veterinary medicine to manage pain and swelling, yet optimal methods for specific tissue depths remain unclear. Cryotherapy modalities, including cold packs (CPs), cold compression (CC), and hyperbaric gaseous cryotherapy (HGC), were applied to nine beagle dogs under general anaesthesia. A custom 3D-printed guide facilitated consistent and accurate measurements of tissue temperatures at depths of 1 and 3 cm. After a 20 min application, all modalities significantly reduced the muscular tissue temperatures at both measured depths. HGC exhibited the most effective rapid temperature reduction, whereas CC displayed the most extended sustained cooling effect. In comparison, CPs showed a lower temperature reduction. The effectiveness of cryotherapy varies with tissue depth, and selecting the appropriate method can improve therapeutic outcome.

Weather conditions in southern Poland at the turn of the 20th century — Insights from archived observational records

This study examines weather conditions in Małopolska (Lesser Poland, southern Poland) from 1861 to 1919, utilizing historical meteorological materials stored in the Archives of the Institute of Meteorology and Water Management — National Research Institute, Poland. The region developed an extensive meteorological network in the latter half of the nineteenth century, preserving daily and sub-daily measurements of air temperature and precipitation, along with notes on socio-economic events and environmental issues. Despite the loss of many early records, the study focuses on 14 measurement points, including the Kraków–Observatory, which has been in operation since 1792 and served as the reference station. Data were digitized through the HISTKLIM project. Analysis revealed that air temperatures in the late 1800s and early 1900s were lower than present-day values, with varied rainfall patterns. The study highlights the substantial value of these historical records, despite gaps and the absence of metadata. Comparing historical weather conditions to current climate normals (1991–2020), the findings contribute to understanding regional climate variability and underscore the importance of preserving archival meteorological data for future research.

AI-powered ultrasonic thermometry for HIFU therapy in deep organ

High-intensity focused ultrasound (HIFU) is considered as an important non-invasive way for tumor ablation in deep organs. However, accurate real-time monitoring of the temperature field within HIFU focal area remains a challenge. Although ultrasound technology, compared with other approaches, is a good choice for noninvasive and real-time monitoring on the temperature distribution, traditional ultrasonic thermometry mainly relies on the backscattered signal, which is difficult for high temperature (>50 °C) measurement. Given that artificial intelligence (AI) shows significant potential for biomedical applications, we propose an AI-powered ultrasonic thermometry using an end-to-end deep neural network termed Breath-guided Multimodal Teacher-Student (BMTS), which possesses the capability to elucidate the interaction between HIFU and complex heterogeneous biological media. It has been demonstrated experimentally that two-dimension temperature distribution within HIFU focal area in deep organ can be accurately reconstructed with an average error and a frame speed of 0.8 °C and 0.37 s, respectively. Most importantly, the maximum measurable temperature for ultrasonic technology has been successfully expanded to a record value of 67 °C. This breakthrough indicates that the development of AI-powered ultrasonic thermometry is beneficial for precise HIFU therapy planning in the future.

Microstructural evolution and high temperature hot corrosion behaviour of AlCoCrFeNiTi high-entropy alloy coatings

The fuels used contain undesirable impurities such as Na, V, K, S, and Mg in gas turbine engines. These impurities react with hot components under service conditions, leading to the deterioration of the thermal barrier coatings (TBCs) structure and the formation of hot corrosion damage. In this study, metallic powders containing CoNiCrAlY were deposited as bond coat on Inconel 718 superalloy material using high velocity oxygen fuel (HVOF) coating technique. High entropy alloy (HEA) powder containing AlCoCrFeNiTi was synthesized as coating material using mechanical alloying (MA) method. AlCoCrFeNiTi powders were produced using atmospheric plasma spray (APS) coating technique. The produced coating system was subjected to hot corrosion tests at 700 °C and 800 °C temperatures for different time periods in corrosive environment conditions containing Na2SO4 (sodium sulfate) and V2O5 (vanadium pentoxide). Hot corrosion behavior of the coating system was determined, damage formations and degradation processes were investigated in detail. As a result of the determination and synthesis of HEA powder materials, production of coatings, experimental studies and hot corrosion test studies under service conditions, it was seen that the Ti-containing AlCoCrFeNi HEA coating system has usable qualities without any damage such as cracking, buckling or spalling.

Fuel mobility dynamics and their influence on applied smouldering systems

Many recent environmentally beneficial applications of smouldering treat hazardous organic liquid fuels in inert porous media. In these applications, organic liquid mobilization can affect the treatment process, and the dynamics are poorly understood. Organic liquid mobilization is therefore a key knowledge gap that hinders the optimization of applied smouldering. This is especially the case in large scales where mobilization appears to be more significant. Liquid mobilization inside a porous medium cannot be easily measured directly, therefore numerical modelling is essential to understand the fundamental processes and to clarify the effects and dynamics of the fuel mobilization on the smouldering reaction. Contrasting numerical models with experimental temperature measurements have revealed many aspects of smouldering that cannot be measured. In this study, a previously developed 1D smouldering model was equipped with multiphase flow equations and compared against laboratory column experiments. The combination of model and experiments has served to quantify the dynamics of organic liquid fuel mobility by simulating high (i.e., non-mobile) and low (i.e., mobile) viscous fuels. The findings from this study shed light on the complicated interplay between multiphase flow, heat and mass transfer, and smoulder chemistry common to many applied smouldering systems. Numerical results confirmed that increasing the viscosity results in fuel remaining in the reaction zone and led to an increase in the peak temperature and smouldering front velocities. Lower viscosity fuels mobilized away from the reaction zone, thereby accumulating fuel in the pre-heating zone of the reactor. The fundamental understanding generated from this research will improve the design, implementation, and optimization of smouldering-based technologies for environmentally beneficial applications worldwide.

A Phone-Based Distributed Ambient Temperature Measurement System With an Efficient Label-Free Automated Training Strategy

A Phone-Based Distributed Ambient Temperature Measurement System With an Efficient Label-Free Automated Training Strategy

Neutron-induced backgrounds in coaxial cables on the South Pole neutron time-of-flight detector at the National Ignition Facility

As neutron yields increase at fusion facilities, a universal symptom the community must deal with is MeV neutron-induced backgrounds in cables running to diagnostics. On the first Gain >1 plasmas in the world, the National Ignition Facility (NIF) neutron time-of-flight (nToF) diagnostic registered significant cable backgrounds that compromised key performance measurements. The South Pole nToF is uniquely located inside the NIF Target Bay shield walls, ∼18 m from the fusion source, and consequently has long coaxial cable runs (>20 m) that see significant neutron fluence. The resulting neutron-driven current in the cable is comparable to the downscattered neutron signal, compromising the downscattered ratio (DSR) measurement. We have characterized this background with a series of on-shot tests and developed a background subtraction technique to mitigate these effects. The background subtracted DSR results are validated against zirconium activation measurements, indicating that we have successfully reclaimed high-quality data output. The ion temperature measurement is found to not be affected by this background. Alternative approaches to addressing neutron-induced cable backgrounds are presented for potential future hardware upgrades.

Sensitive multimode luminescence thermometry through CaZnOS:Pb2+/Mn2+ microcrystals

Developing advanced luminescent thermometers that offer various thermometry modes is essential for remote temperature measurement with high precision. In this study, a novel tri-mode optical thermometer was designed using Pb2+ and Mn2+ co-doped CaZnOS microcrystals. The structure, luminescence properties, energy transfer (ET) mechanism, and temperature sensing performance were comprehensively investigated. Dual emission of Pb2+ and Mn2+ was achieved by excitation at 290 or 358 nm. Additionally, ET from Pb2+ to Mn2+ was demonstrated in the CaZnOS host. Based on excellent temperature-dependent optical properties, parameters including luminescence intensity ratio (LIR), coordinates of Commission Internationale de L'Eclairage (CIE), and excitation intensity ratio (EIR) were developed for temperature sensing. The maximum relative sensitivity (Sr) is 2.92% K−1 (303 K) through LIR mode, 0.562% K−1 (324 K) through CIE mode, and 0.879% K−1 (303 K) through EIR mode, respectively. The excellent thermometric performance indicates the rationally designed material has great potential in multimode optical thermometry.

Fluorescent Polymer Composites Based on Core-Shell NaYF4:Yb/Er@NaGdF4:Ce/Tb Structures for Temperature Monitoring and Anti-Counterfeiting Protection

Synthesis and detailed morphological, structural, and photophysical analysis were conducted on core@shell NaYF4:Yb/Er@NaGdF4:Ce/Tb nanoparticles (C/S NPs). It was found that the NaGdF4:Ce/Tb shell significantly reduces defects in the NaYF4:Yb/Er core, enhancing the emission resolution of Er3+ ions. These C/S NPs exhibit dual luminescence functionality: upconversion with a quantum yield of 0.19%, driven by energy transfer between Yb3+ and Er3+ ions, and downshifting luminescence with a remarkable quantum yield of 96%, attributed to the energy transfer between Ce3+ and Tb3+ ions. Polymer nanocomposites, polystyrene-C/S (PS-C/S), and polyvinyl acetate-C/S (PVA-C/S) were synthesized by co-dissolving the polymers and nanoparticles in chloroform, followed by the removal of chloroform. Thin films based on the PS-C/S composite exhibited upconversion luminescence, enabling spatial temperature measurements with a lateral resolution of 10 μm and an accuracy of 1.6 K on a non-uniformly heated sample. The PVA-C/S composite exhibited dual-mode luminescence (upconversion and downshifting), which was employed to create fluorescent images activated by either NIR or UV irradiation. Additionally, these images demonstrated high stability against alcohols, acetone, and alkaline aqueous solutions, offering new anti-counterfeiting measures.

The generation mechanism of cutting heat and the theoretical prediction model for temperature on the rake face of the cutting tool in Zirconia ceramics

Cutting temperature and its distribution are crucial factors influencing tool strength and wear rate, due to the hardness and brittleness of Zirconia (ZrO2) ceramics, significant challenges arise in both direct temperature measurement in the cutting zone and theoretical analysis of cutting heat. Thus, focusing on the turning characteristics of ZrO2 ceramics, this study analyzes the mechanism of cutting heat generation and proposes utilizing thermodynamic state equations to determine the cutting heat source on rake face of tool. Based on the heat source method, a theoretically prediction model for temperature distribution on rake face is established. This model considers primary cutting parameters, workpiece material properties, crack fracture characteristics of the machined surface, and thermal characterizations of the tool material. The relationship between tool wear and cutting temperature is experimentally analyzed to determine the characteristic temperature that indicates the initial stage of tool wear. The validity of the theoretical model is verified, as the predicted results show high consistency with experimental results within the range of experimental parameters, with a relative error within 15.2 %.The results reveal the highest temperature during brittle cutting occurs within the cutting layer area, with the highest temperature occurring approximately 50 μm from the tool tip, followed by a gradual decrease beyond 150-200 μm. This study also demonstrates that cutting heat in ceramic turning does not solely originate from friction heat between tool flank-workpiece but also includes impact heat from tool rake face-workpiece, which under certain cutting parameters exerts a more significant influence on cutting temperature. This model can facilitate the selection and optimization of cutting process parameters for brittle materials and provide a theoretical basis for analyzing the relationship between tool thermal damage, thermophysical properties, and tool wear.

Monitoring soil cracking using OFDR-based distributed temperature sensing framework

Soil cracking induced by extreme drought represents a widespread natural phenomenon occurring across the earth surface, capable of triggering multiple weakening mechanisms within surface soils, potentially leading to the instability and failure of slopes and agricultural infrastructures. This study proposes an innovative geophysical monitoring framework for detecting field soil cracking by combining the actively heated fiber-optic (AHFO) method and distributed fibre optical sensing (DFOS) based on optical frequency domain reflectometry (OFDR) technique, referred to as AH-OFDR framework. Laboratory calibration tests, field monitoring tests, numerical simulations, and sensitivity analyses were employed to comprehensively evaluate the feasibility, effectiveness, and limitations of the AH-OFDR framework for soil crack monitoring. Laboratory calibration confirmed that the DFOS-OFDR technique achieves a minimum spatial resolution and readout accuracy of 1 mm, along with a temperature measurement accuracy of ±0.1 °C. Field monitoring verified that the AH-OFDR framework can accurately detect soil cracks ranging in width from 0.01 m to 0.12 m. Additionally, numerical simulations not only validated the effectiveness of the AH-OFDR framework across a broader range of crack widths, from 0.01 m to 0.50 m, but also established a quantitative relationship between temperature changes and the spatial distribution of crack positions and widths. Notably, a critical crack width threshold of 0.30 m was identified within the AH-OFDR framework, significantly impacting the prediction of soil crack widths. Sensitivity analysis demonstrated the remarkable crack detection capabilities of the AH-OFDR framework, irrespective of the soil crack width and spacing. The AH-OFDR framework holds substantial potential as an innovative and high-resolution observational method for advancing our understanding of diverse geological and hydrogeological processes.