Precise Temperature Measurement Research Articles

Ratiometric Upconversion Temperature Sensor Based on Cellulose Fibers Modified with Yttrium Fluoride Nanoparticles.

In this study, an optical thermometer based on regenerated cellulose fibers modified with YF3: 20% Yb3+, 2% Er3+ nanoparticles was developed. The presented sensor was fabricated by introducing YF3 nanoparticles into cellulose fibers during their formation by the so-called Lyocell process using N-methylmorpholine N-oxide as a direct solvent of cellulose. Under near-infrared excitation, the applied nanoparticles exhibited thermosensitive upconversion emission, which originated from the thermally coupled levels of Er3+ ions. The combination of cellulose fibers with upconversion nanoparticles resulted in a flexible thermometer that is resistant to environmental and electromagnetic interferences and allows precise and repeatable temperature measurements in the range of 298–362 K. The obtained fibers were used to produce a fabric that was successfully applied to determine human skin temperature, demonstrating its application potential in the field of wearable health monitoring devices and providing a promising alternative to thermometers based on conductive materials that are sensitive to electromagnetic fields.

Enzyme-modulated photothermal immunoassay of chloramphenicol residues in milk and egg using a self-calibrated thermal imager

Highly sensitive and accurate detection of chloramphenicol is of paramount importance for food safety. Herein, an enzyme-modulated photothermal immunosensor that uses a self-calibrated thermal imaging system (SCTIS) as signal read-out was developed for detecting chloramphenicol. In this immunosensor, alkaline phosphatase was used as a modulator of the photothermal conversion. It could hydrolyze the substrate into ascorbic acid, thereby reducing oxidized 3,3′,5,5′-tetramethylbenzidine, which exhibited a near-infrared laser-driven photothermal effect. For precise temperature measurement, the SCTIS was designed by using the temperature compensation of a ceramic chip to enable real-time self-calibration of the temperature. This SCTIS-based immunosensor could detect chloramphenicol with a LOD of 9 pg/mL in 2 h, and relative standard derivations from 3.95% to 13.58%. The average recoveries in milk and egg samples ranged from 76% to 114%. This versatile sensing strategy can detect various targets by altering recognition elements, thus has wide applicability in food safety testing and monitoring.

IOT Based Health Monitoring System for Covid Patients Monitoring

Currently, the COVID-19 pandemic is one of the major global issues faced by health organizations. As a person enters old age, it becomes increasingly vital for them to undergo standard medical health checkups. Since it may be time-consuming and difficult for most people to get regular health checkup appointments, IoT-based arrangements can be beneficial to individuals for routine health checkups. We are utilizing the internet of things to monitor several characteristics of the patient in this project. The real-time parameters of a patient’s health are transferred to the cloud via Internet connectivity in the patient Monitoring system based on the Internet of things project. These parameters are transmitted to IoT server where people can access them from any point on the planet. We demonstrate a multi-parameter Wearable sensor system that works in tandem with the Internet of Things to provide real-time, unobtrusive Monitoring of core body temperature and heart rate. Clinical study demonstrating the importance of sustaining precise measurements of core heartbeat and body temperature in the ambulatory environment and during Activity to examine human thermoregulation. We use a wireless multisensory system to monitor the temperature of the body as well as the pulse of the heart.

Kalman Filter Based High Precision Temperature Data Processing Method

Obtaining high precision temperature data is crucial in spaceflight applications, considering the growing demand for high precision temperature measurement and the limited onboard resources with a harsh thermal environment in the spacecraft. How to obtain the data, however, becomes an urgent problem. Kalman filtering method is one of the solutions to obtain high precision temperature data with such limited resources. In this paper, the authors demonstrate the principle of temperature measurement system, the application of Kalman filter in temperature measurement including the processing method of sensor self-heating effect, and establishes the state space of measurement error and system error. Through the test, it could be seen that Kalman filtering can improve the temperature measurement resolution to the order of 100 μK while effectively reducing the temperature measurement bias.

Fiber optic high temperature sensor based on ZnO composite graphene temperature sensitive material

The working temperature of the cable is particularly important for the safe operation of the power system, which requires high temperature detection for its working environment, but the sensitivity of the ordinary optical fiber temperature sensor in the high temperature state cannot meet this demand. For this purpose, an optical fiber high temperature sensor based on ZnO composite graphene temperature sensitive material is developed in this paper. MMF-TSCF-MMF temperature sensing unit is composed of two sections of multimode fiber (MMF) and a tapered seven core fiber (TSCF). Three different shapes of ZnO@Gr (ZnO composite graphene) temperature-sensitive materials were prepared by hydrothermal method. The experimental results show that the sensor has high stability and good interference effect. Meanwhile, the wavelength sensitivity reached 0.33268 nm/°C in a temperature measurement range of 89–98 °C. The fiber sensor is used for precision temperature measurement of cable temperature in fields such as electrical engineering due to its high temperature sensitivity, small size and low cost.

A new solar powered robotic arm guided master–slave electric motors of biomass conveyor

PurposeElectric motor heating during biomass recovery and its handling on conveyor is a serious concern for the motor performance. Thus, the purpose of this paper is to design and develop a hardware prototype of master–slave electric motors based biomass conveyor system to use the motors under normal operating conditions without overheating.Design/methodology/approachThe hardware prototype of the system used master–slave electric motors for embedded controller operated robotic arm to automatically replace conveyor motors by one another. A mixed signal based embedded controller (C8051F226DK), fully compliant with IEEE 1149.1 specifications, was used to operate the entire system. A precise temperature measurement of motor with the help of negative temperature coefficient sensor was possible due to the utilization of industry standard temperature controller (N76E003AT20). Also, a pulse width modulation based speed control was achieved for master–slave motors of biomass conveyor.FindingsAs compared to conventional energy based mains supply, the system is self-sufficient to extract more energy from solar supply with an energy increase of 11.38%. With respect to conventional energy based \\ of 47.31%, solar energy based higher energy saving of 52.69% was reported. Also, the work achieved higher temperature reduction of 34.26% of the motor as compared to previous cooling options.Originality/valueThe proposed technique is free from air, liquid and phase-changing material based cooling materials. As a consequence, the work prevents the wastage of these materials and does not cause the risk of health hazards. Also, the motors are used with their original dimensions without facing any leakage problems.

High Temperature Melting Curve of Basaltic Glass by Laser Flash Heating

Basalt is an igneous rock originating from the cooling and solidification of magma and covers approximately 70% of Earth’s surface. Basaltic glass melting in the deep Earth is a fundamental subject of research for understanding geophysics, geochemistry, and geodynamic processes. In this study, we design a laser flash heating system using two-dimensional, four-color multi-wavelength imaging radiometry to measure the basaltic glass melting temperature under high pressure conditions in diamond anvil cells. Our experiment not only determines the temperature at the center of heating but also constructs a temperature distribution map for the surface heating area, and enables us to assess the temperature gradient. Through precise temperature measurements, we observe that the basaltic glass melting temperature is higher than those in previous reports, which is near the normal upper-mantle isotherm, approaching the hot geotherm. This suggests that basalt should not melt in most of the normal upper mantle and the basaltic melts could exist in some hot regions.

Precise surface temperature measurements at kHz-rates using phosphor thermometry to study flame-wall interactions in narrow passages

The thermographic phosphor ScVO4:Bi3+ is used to obtain time-resolved surface temperature measurements with sub- °C precision at 5 kHz. Measurements are used to study transient heat loss and flame-wall interactions (FWI) within a dedicated narrow two-wall passage (crevice) in an optically accessible fixed volume chamber. This passage emulates a crevice relevant in many technical environments, where FWI is less understood due to lack of detailed measurements. Chemiluminescence (CH*) imaging is performed simultaneously with phosphor thermometry to resolve how the flame's spatiotemporal features influence the local surface temperature. ScVO4:Bi3+ is benchmarked against Gd3Ga5O12:Cr,Ce, a common phosphor used at low-kHz rates in FWI environments. ScVO4:Bi3+ is shown to offer higher luminescence signal levels and temperature sensitivity as well as negligible cross dependence on the excitation laser fluence, improving the precision and repeatability of the wall temperature measurement. ScVO4:Bi3+ is further used to resolve transient heat loss for variations in crevice spacing and uniquely capture temperature transients associated with flame dynamics. Taking advantage of these precise surface temperature measurements the wall heat flux is calculated with crevice spacing of 1.2 mm, where flame extinction is prevalent. Wall heat flux and estimated quenching distance are reported for flames that actively burn or extinguish at the measurement location.

Experimental study on emissivity setting before precise temperature measurement of SiCp/Al cutting by infrared thermal imager

Experimental study on emissivity setting before precise temperature measurement of SiCp/Al cutting by infrared thermal imager

Ultrafast multi-photon excitation of ScVO4:Bi3+ for luminescence thermometry.

We demonstrate a multi-photon excitation (MPE) scheme for luminescence thermometry using ScVO4:Bi3+. MPE is performed using a 37 fs Ti:sapphire laser pulse centered at 800 nm. Log-log plots of the phosphorescence intensity versus excitation power show that the 800 nm MPE of ScVO4:Bi3+ involves a 2- and 3-photon absorption process in comparison with a single-photon excitation (SPE) process at 266 and 400 nm. Spectroscopic investigation shows that with the 800 nm MPE and 266 nm SPE schemes, the emission spectra of ScVO4:Bi3+ are similarly characterized by emissions of the VO4 3- groups and Bi3+. MPE is advantageous to suppress fluorescence that interferes with the phosphorescence signal. We demonstrate this aspect for a ScVO4:Bi3+ coating applied on an alumina substrate. The luminescence lifetime is calibrated with temperature in the range of 294-334 K; the MPE scheme has an equally impressive temperature sensitivity (3.4-1.7%/K) and precision (0.2-0.7 K) compared with the SPE schemes. The MPE scheme can be applied to a variety of phosphors and is valuable for precise temperature measurements, even in applications where isolating interfering background emissions is challenging.

The Precise Temperature Measurement System with Compensation of Measuring Cable Influence

The article presents an active bridge system that enables the solution of a significant problem consisting in ensuring correct indications of temperature values in a wide measuring range for a Pt100 temperature sensor with properties defined by the standard (EN-60751 + A2). The presented active bridge system combines the properties of the measuring amplifier with the stabilization of the current value in the branch in which the Pt100 sensor was placed. The article focuses on the comparison of the temperature measurement in a typical resistance bridge and the measurement made in the developed active bridge, which has also become the subject of a patent. For the performed tests, in which the correctness of the temperature measurement system operation was verified, and on the basis of the obtained results, the quality of temperature measurements was compared in a wide range of changes.

Precise surface temperature measurements from 400 to 1200 K using the Pr:YAG phosphor

Precise surface temperature measurements from 400 to 1200 K using the Pr:YAG phosphor

Accelerated lifetime testing of thin‐film solar cells at high irradiances and controlled temperatures

AbstractWithin this study, we investigate the intrinsic photostability of thin‐film solar cells, here organic photovoltaic cells. Since degradation under natural sun light proceeds within the timeframe of months and years, the process needs to be speeded up for fast material analysis and screening, using high‐concentration accelerated lifetime testing (high‐C ALT). For this purpose, we established setups allowing irradiances of up to 730 sun equivalents (SE). One key finding of our study is that accelerating the testing procedure by such large intensities is possible but a precise measurement and control of the solar cell temperature is absolutely essential. Accordingly, we developed an innovative method of determining the temperature of the active layer which offers significant advantages over commonly used measurement methods. Furthermore, it was found that the degradation process under high illumination densities can be well described by a stretched exponential law. We demonstrate that the temperature kinetics of P3HT:PCBM was found to be Arrhenius governed with an activation energy of 27.2 kJ/mol under continuous illumination of 300 SE. Finally, it was shown that the velocity of light‐induced degradation of short‐circuit current depends linearly on the used irradiance dose at a given temperature starting from normal illumination conditions up to at least 300 SE. This makes high‐C ALT a very valuable tool for swift screening of the lifetime of novel thin‐film solar cells and materials.

Mach-Zehnder Interferometer for In-Situ Non-Contact Temperature Monitoring During Thermal Processing of an Optical Fibre

A Mach-Zehnder interferometer is formed in the transverse plane of an optical fibre. This is exploited to monitor the temperature of any given optical fibre in real time, without any predesigned temperature sensing elements engineered into the fibre and without a need to access the fibre ends. The interferometer is formed by the refraction at the air-glass interface and the subsequent internal reflections within the fibre. The temperature response of the fibre is then measured by quadrature phase shift detection of the interference pattern. For context, this is compared to finite element modelling and a previously studied Fabry-Pérot interferometer configuration. The temperature of an optical fibre was measured from room temperature up to 1174 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> C with an error of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm 2.6\%$</tex-math></inline-formula> for the Mach-Zehnder type interferometer. The measurement techniques presented offer a useful tool for precise temperature measurement for applications such as fibre post-processing.

Thermal Sensor Calibration for Unmanned Aerial Systems Using an External Heated Shutter

Uncooled thermal infrared sensors are increasingly being deployed on unmanned aerial systems (UAS) for agriculture, forestry, wildlife surveys, and surveillance. The acquisition of thermal data requires accurate and uniform testing of equipment to ensure precise temperature measurements. We modified an uncooled thermal infrared sensor, specifically designed for UAS remote sensing, with a proprietary external heated shutter as a calibration source. The performance of the modified thermal sensor and a standard thermal sensor (i.e., without a heated shutter) was compared under both field and temperature modulated laboratory conditions. During laboratory trials with a blackbody source at 35 °C over a 150 min testing period, the modified and unmodified thermal sensor produced temperature ranges of 34.3–35.6 °C and 33.5–36.4 °C, respectively. A laboratory experiment also included the simulation of flight conditions by introducing airflow over the thermal sensor at a rate of 4 m/s. With the blackbody source held at a constant temperature of 25 °C, the introduction of 2 min air flow resulted in a ’shock cooling’ event in both the modified and unmodified sensors, oscillating between 19–30 °C and -15–65 °C, respectively. Following the initial ‘shock cooling’ event, the modified and unmodified thermal sensor oscillated between 22–27 °C and 5–45 °C, respectively. During field trials conducted over a pine plantation, the modified thermal sensor also outperformed the unmodified sensor in a side-by-side comparison. We found that the use of a mounted heated shutter improved thermal measurements, producing more consistent accurate temperature data for thermal mapping projects.

In-situ lattice structure analysis in sp2 hybridization of stable carbon isotopes: Precision modelling of temperature

Quantum temperature measurement in graphene thermal applications is intrinsically coupled to the crystal structure, phonon frequency, and kinetic isotope effect. Precision temperature measurement is a vital technology to characterize the thermal performance of quantum systems. Heat in nanoscale devices is typically modelled in terms of phonon properties by the nonequilibrium function for high temperature and by the transport theory formalism for low temperature that dealt with phonon interaction at the molecular level. In this paper, we investigate the lattice structure of isotope-12 pristine graphite and isotope-13 multi walled carbon nanotubes through the measured 2θ value at the peak of maximum intensity by in-situ X-ray diffractometer from 50 °C steps up to 1200 °C and confined the quantum well system into the hexagonal lattice volume. The likelihood states of the π-nearly free electron in the carbon atom and the electron-phonon probability distribution function are used to identify the system's thermal state region. By performing realistic quantum harmonic oscillator relations that account for the contribution of electron-phonon coupling and atomic mass, we achieved a precision temperature measurement of the quantum system despite the native disorder in sp2 hybridization of different carbon allotropes and introduced a new technique for differentiating carbon isotopes.

Temperature Measurement and Control Application in a Laser Plastic Surgery Real Temperature Detection System

The purpose of this study was to grasp the development process of thermal image temperature measurement technology. It provides directional support for the optimization development of the thermal imagery and laser plastic surgery and laser treatment. This paper uses the infrared thermal image temperature measurement principle and performs infrared thermal image precise temperature measurement technology and its application research. The results showed that there was a correlation between 595 nm pulse dye laser, age, laser energy density, and skin temperature ( P &lt; 0.05 ). There is a significant difference in the average ( P &lt; 0.05 ). The infrared thermal imagery temperature monitoring system is a simple and relatively accurate temperature detection system that can be widely used in temperature measurement and control of laser plastic surgery.

Pool Boiling Heat Transfer Coefficients in Mixtures of Water and Glycerin

Heat transfer coefficients were investigated for saturated nucleate pool boiling of binary mixtures of water and glycerin at atmospheric pressure in a wide range of concentrations and heat fluxes. Mixtures with water mass fractions from 100% to 40% were boiled on a horizontal flat copper surface at heat fluxes from about 25 up to 270kWm−2. Experiments were carried out by static and dynamic method of measurement. Results of the static method show that the impact of mixture effects on heat transfer coefficient cannot be neglected and ideal heat transfer coefficient has to be corrected for all investigated concentrations and heat fluxes. Experimental data are correlated with the empirical correlation α=0.59q0.714+0.130ωw with mean relative error of 6%. Taking mixture effects into account, data are also successfully correlated with the combination of Stephan and Abdelsalam (1980) and Schlünder (1982) correlations with mean relative error of about 15%. Recommended coefficients of Schlünder correlation C0=1 and βL=2×10−4ms−1 were found to be acceptable for all investigated mixtures. The dynamic method was developed for fast measurement of heat transfer coefficients at continuous change of composition of boiling mixture. The dynamic method was tested for water–glycerin mixtures with water mass fractions from 70% down to 35%. Results of the dynamic method were found to be comparable with the static method. For water–glycerin mixtures with higher water mass fractions, precise temperature measurements are needed.

3D printed optofluidic biosensor: NaYF4: Yb3+, Er3+ upconversion nano-emitters for temperature sensing

The nonintrusive, realtime, and accurate measurement of the local temperature has applications in a variety of scenarios. This need has led to significant research to develop novel nanophotonic sensors. In this paper, a 3D-printed optofluidic chip is nano-engineered for local, contactless, and precise optical measurement of temperature in microfluidic channels using lanthanide-doped upconversion nanoparticles. Temperature sensing nano-emitters are doped in a UV-curable matrix and embedded into a microfluidic channel using maskless photolithography. Photoluminescence of NaYF4:Yb3+, Er3+ upconversion nanoparticles have two bands in the green spectrum in which the PL maximums at 521 nm and 541 nm are used for temperature sensing. Thus, enabling ratiometric temperature sensing when excited using near-infrared light, which is desirable for measurements in biological and biomedical settings. The functionality of the temperature sensor for local and nonintrusive measurements in a microalgae culture medium is demonstrated.

Automated plasmon peak fitting derived temperature mapping in a scanning transmission electron microscope

Nanoscale thermometry, an approach based on non-invasive, yet precise measurements of temperature with nanometer spatial resolution, has emerged as a very active field of research over the last few years. In transmission electron microscopy, nanoscale thermometry is particularly important during in situ experiments or to assess the effects of beam induced heating. In this article, we present a nanoscale thermometry approach based on electron energy-loss spectroscopy in a transmission electron microscope to measure locally the temperature of silicon nanoparticles using the energy shift of the plasmon resonance peak with respect to the zero-loss peak as a function of temperature. We demonstrate that using non-negative matrix factorization and curve fitting of stacked spectra, the temperature accuracy can be improved significantly over previously reported manual fitting approaches. We will discuss the necessary acquisition parameters to achieve a precision of 6 meV to determine the plasmon peak position.