Remote Temperature Measurement Research Articles

Rb2InCl5·H2O doped with Te4+ for fluorescence thermometry and coordinated water-related structural phase transformation.

Here, we synthesized Rb2InCl5·H2O with x Te4+ doping by the coprecipitation method, which converts the original nonluminance for pure Rb2InCl5·H2O into orange luminescence ascribed to Te4+ incorporation with an emission peak at 648 nm and a full width at half maximum of 142 nm (420.3 meV) at room temperature. The photoluminescence (PL) lifetime of Te4+-doped Rb2InCl5·H2O exhibits a strong temperature dependence, with a maximum absolute sensitivity (SA) of 12 × 10-3 K-1 at 260 K and a relative sensitivity (SR) of 3.5%K-1 at 300 K, demonstrating its capability for non-contact remote temperature measurement. Additionally, we capture the dynamic changes of coordinated water with temperature in Rb2InCl5·H2O through temperature-dependent Raman spectroscopy, analyze the resulting structural phase transformation associated with coordinated water, and investigate the reversibility of this phase transformation.

Precision across temperatures: Eu/Tb luminescent thermometer with exceptionally high and stable sensitivity from 180 to 320 K

Luminescence thermometry, leveraging the temperature-dependent luminescent properties of coordination compounds, offers precise and remote temperature measurement. However, many existing luminescent thermometers exhibit a narrow peak in temperature sensitivity, restricting their effective operating range. In this study, we synthesized new complexes [LnL2(NO3)(TPPO)2], where Ln = Eu (1), Tb (2), Gd (3), Tb0.94Eu0.06 (4), (HL - 4,4,4-trifluoro-1-(furan-2-yl) butan-1,3-dione, TPPO - triphenylphosphine oxide, which demonstrate an exceptionally wide and stable range of maximum temperature sensitivity of 3 %×K−1, spanning from 180 to 320 K. Furthermore, the temperature uncertainty remained low and stable across the same temperature region, ensuring reliable measurements. An unusual behavior was observed in the ion-to-ion energy transfer process rate constant, which exhibited an additional peak between 120 and 180 K. This phenomenon warrants further investigation to fully understand the underlying mechanisms. The obtained results allow for creation of new highly efficient luminescent thermometers tailored for specific complex applications, including cryobiology and microfluidics.

High-Accuracy Calibration Method of a Thermal Camera Using Two Reference Blackbodies.

Body temperature is one of the most important physiological parameters of a human being used to assess his basic vital functions. In medical practice, various types of measuring instruments are used to measure temperature, such as liquid thermometers, electronic thermometers, non-contact ear thermometers, and non-contact forehead thermometers. Such body temperature measurement techniques require the connection of appropriate sensors to a person, and non-contact thermometers operate over short distances and force a specific position of the person during the measurement. As a result, using the above methods, it is practically impossible to perform body temperature measurements of a moving human being. A thermal imaging camera can be used effectively for the purpose of the temperature measurement of moving objects, but the remote measurement of a human body temperature using a thermal imaging camera is affected by many factors that are difficult to control. Accurate remote measurement of human body temperature requires a measurement system that implements a specialized temperature determination algorithm. This article presents a model of a measurement system that facilitates the development of a highly accurate temperature measurement method. For the model, its parameters were determined on the calibration stand. The correct operation of the developed method and the effectiveness of temperature measurement have been confirmed by tests on a test stand using reference radiation sources.

Regulating Arrhenius Activation Energy and Fluorescence Quantum Yields of AuNCs-MOF to Achieve High Temperature Sensitivity in a Wide Response Window.

Luminescent thermometry affords remote measurement of temperature and shows huge potential in future technology beyond those possible with traditional methods. Strategies of temperature measurement aiming to increase thermal sensitivity in a wide temperature response window would represent a pivotal step forward, but most thermometers cannot do both of them. Herein, we propose a balancing strategy to achieve a trade-off between high Arrhenius activation energy (Ea), which could stretch the temperature response windows, and fluorescence quantum yields (QYs) in a manner that will increase thermal sensitivity in a wide response window. In particular, a luminescent thermometer composed of AuNCs-MOF is prepared via a facile impregnation process to enhance QYs and Ea, responsible for high relative sensitivity (Sr) (15.6% K-1) and ultrawide temperature linearity range (from 83 to 343 K), respectively. Taking fluorescence intensity and lifetime as multiple parameters, the maximum Sr can reach 22.4% K-1 by multiple linear regression. The maximum Sr and temperature response range of the proposed thermometer outperform those of the most recent luminescent thermometers. The strategy of balancing Sr and thermal response range by regulating Ea and QYs enables the construction of ultra-accurate thermal sensors in the age of artificial intelligence.

Fuzzy logic based thermal image processing for temperature monitoring of rotating cylindrical surfaces

When a non-contact and remote temperature measurement is of importance, several environmental factors must be considered. Of these, two are of crucial importance — the surface emissivity of the observed object and the directional emissivity in the object–sensor relationship. This paper proposes FDEM — a Fuzzy Directional Emissivity Model built with the assumption that the observed surface is cylindrically shaped. The model consists of two submodels — for vertical and horizontal directions separately. The main contribution of this paper is the formalization of a linguistic description of measurement conditions typical for an industrial environment. Additionally, dual linguistic fuzzy modifiers were used to increase the accuracy of the modeled emissivity. Finally, the proposed model achieved up to 40% reduction of RMSE error when used for correcting the temperature measurements of a rotating cylinder. Overall, our model provides a novel and reliable way for temperature readout correction on the entire surface of a drying roller, such as ones used in the papermaking industry. Furthermore, the proposed approach is not only inherently capable of compensating for the position of the camera, but also does it in an interpretable, and hence expert-verifiable, manner.

Analiza porównawcza wybranych metod kalibracji kamery termowizyjnej z chłodzonym detektorem pracującym w zakresie MWIR

For accurate remote temperature measurement with a thermal imaging camera, it is necessary to perform radiometric calibration. This allows the radiative parameters of an object, and therefore its temperature, to be related to the response of the infrared detector observing it. The article presents the basic concepts related to radiometric calibration and various factors influencing its effectiveness. The most common calibration methods were also reviewed, and then two of them were implemented and compared on a specially constructed laboratory station, using proprietary software and equipped with a cooled infrared camera, operating in the MWIR range. The camera was calibrated in the temperature range from 20 °C to 50 ° C. The comparison of methods was carried out on the basis of a series of temperature measurements, analysis of absolute and relative errors, as well as analysis of the dispersion of the measured temperature values.

High sensitivity temperature sensing material In2Li3P3O12: Bi3+, Eu3+ based on effective energy transfer from Bi3+ to Eu3+

In recent years, fluorescent temperature sensing materials have been widely studied because they can realize remote non-destructive temperature measurement. High temperature sensitivity and excellent temperature resolution are the eternal pursuit of fluorescence temperature sensing. Here, we report the preparation, structure, luminescent properties and temperature sensing performance of phosphor In2Li3P3O12: Bi3+, Eu3+. Eu3+ singly doped samples can emit red light under 270 nm excitation. There is effective energy transfer from Bi3+ to Eu3+ in the Bi3+ and Eu3+ co-doped samples. Doping Bi3+ on the basis of doping Eu3+ can significantly enhance the luminescence intensity of Eu3+ ions. Ultraviolet light from Bi3+ and red light from Eu3+ are chosen to design a fluorescence intensity ratio thermometer for more accurate temperature detection. The temperature sensing technology has a maximum absolute and relative sensitivity is up to 0.0087 K−1 at 298 K−1 and 2.71 % K−1 at 325 K, respectively. This has a higher sensitivity than many phosphors available on the market. This indicates that it is a kind of fluorescence temperature sensing material with great potential.

Multipoint temperature measurement system composed of fiber-optic Fabry–Perot interference sensors and a wavelength-division multiplexing filter

A multipoint optical-fiber remote temperature measurement system was developed using reflection-type sensors consisting of a Fabry–Perot interference (FPI) structure with good temperature characteristics combined with a wavelength-division multiplexing (WDM) filter. The FPI sensor was fabricated using a short temperature-sensing region sandwiched between single-mode fibers. FPI optical fibers and a WDM filter functioned as the temperature sensors and wavelength-selective optical source using an amplified spontaneous emission light source, respectively. This system was operated in a dense WDM configuration using an arrayed waveguide wavelength filter.

Visible TADF and NIR Quenching Emission of Chromium Activated Zirconium‐Halide Perovskite Toward Ultra‐High‐Sensitive Ratiometric Fluorescent Thermometer

AbstractWith the development of science and technology, the measurement of temperature is receiving more and more attention. However, ratiometric fluorescent thermometers based on thermally coupled energy levels remain challenging because of their low relative sensitivity (Sr). In this work, chromium activated zirconium‐halide perovskite Cs2ZrCl6 microcrystals are successfully synthesized via a simple co‐precipitation method at room temperature. Interestingly, the host Cs2ZrCl6 exhibits reverse thermal quenching due to its thermal‐activated delayed fluorescence (TADF) behavior, while the Cr3+ dopant shows normal thermal quenching. Leveraging the difference in their temperature‐dependent luminescent properties, a ratiometric fluorescent thermometer is ingeniously developed, whose Sr reaches a maximum of 4.23% K−1. Besides, the as‐synthesized thermometer is demonstrated for mobile phone remote temperature measurement. This finding offers a new approach for the design of high‐sensitivity ratiometric fluorescent temperature sensors.

Design and use of a wireless temperature measurement network system integrating artificial intelligence and blockchain in electrical power engineering.

This work aims to investigate the potential fire hazard stemming from the overheating of power equipment. The advent of the artificial intelligence era has facilitated the fusion of blockchain and Internet of Things (IoT) technologies. This work delves into the technical standards for IoT equipment monitoring and smart grid communication, and the IoT environment of power grid equipment. This work introduces a temperature monitoring network tailored for IoT wireless power equipment suitable for the power environment, and conducts system debugging in the power laboratory. The findings affirm that the temperature out-of-limit alarm testing has met the required criteria, confirming the system's ability to issue timely warnings when temperatures breach a predefined threshold, effectively avoiding high-temperature misfires. This work fully harnesses the secure and user-friendly operation of smart blockchain and the wireless sensing technology of the IoT to realize online monitoring and remote temperature measurement of the power system. It can effectively prevent equipment from overheating and damage, and promote the development of equipment condition monitoring technology in electric power engineering.

Time-gated multi-dimensional luminescence thermometry via carbon dots for precise temperature mobile sensing.

Luminescence thermometry presents precise remote temperature measurement capabilities but faces significant challenges in real-world applications, primarily stemming from the calibration's susceptibility to environmental factors. External factors can compromise accuracy, necessitating resilient measurement protocols to ensure dependable temperature (T) readings across various settings. We explore a novel three-dimensional (3D) approach based on time-gated (t) luminescence thermometric parameters, Δ(T,t), employing physical mixtures of surface-engineered carbon dots (CDs) based on dibenzoylmethane and rhodamine B. These CDs showcase enduring, temperature-responsive, and customizable phosphorescence, easily activated by low-power LEDs and distinguished by their prolonged emission time due to thermally activated delayed phosphorescence. Quantifying the thermal emission dependency is achievable through conventional spectrometer analyses or by capturing photographs with a smartphone's camera under flashlight illumination, yielding up to 30 time-gated ratiometric thermometric parameters per sample. Notably, within the temperature range of 23-45 °C, the maximum relative sensitivity of 7.9% °C-1 surpasses current state-of-the-art CD-based thermometers and ensures temperature readout with low-resolution portable devices as non-modified smartphones.

Towards High-Quality Broad-Range Luminescence Thermometry - the Case of Pr3+-Activated Garnets

Accurate and sensitive remote temperature measurement over a wide range of temperatures, presumably 1000 degrees, is required in many existing and emerging applications. Novel and emerging technologies pose new requirements on the quality of temperature measuring, the resistance to disturbance by external electric and/or magnetic fields, spatial resolution, and the operating range of thermometers. Luminescence thermometry has the potential to become the technology of choice when classic methods become non-practical and/or do not offer the expected quality.Designing a luminescence thermometer capable of measuring temperature reliably over, for example, 1000 degrees range is challenging, as managing luminescence processes in such a range is extremely difficult. Yet, wide-range luminescence thermometers are of interest in such fields as aviation, space, nuclear plant, and others. Fast, accurate, and credible measurements of quickly changing temperatures are critical in these areas.In this presentation, we shall report on the thermometric competencies of a series of garnet phosphors, typically activated with Pr3+. We shall focus on the possibility of managing the physics related to energy flow between the excited levels of Pr3+ and thermal quenching of its three emissions resulting from the 5d®4f, 3PJ®3HJ and 1D2®3HJ transitions. Not only shall we demonstrate that the sensitivity of such sensors may be deliberately tuned to reach its maximum at temperatures where it is most needed, but we will also show that garnets nowadays may offer temperature measuring over a range of 800 degrees at least. This research was supported by the Polish National Science Center (NCN) under the grant #UMO2018/29/B/ST5/00420. Figure 1

Self-powered temperature sensors harnessing membrane potential of living cells

In this paper we present a novel method for remote temperature measurements of a bio-cell and its immediate surroundings, based on the use of electrical energy harvested from a single soleus muscle fiber. Our method employs an optimized RLC circuit, embedded with the cell, where the capacitor serves both as an energy storage unit and a temperature sensor, exploiting its natural temperature sensitivity. Once charged, the RLC oscillator emits a radio signal at a frequency that is dependent on the temperature. This signal can be received wirelessly through a receiver, facilitating remote temperature measurement. We present experimental tests performed on soleus muscle from mouse, where a maximum output voltage of – 70 mV is attained on a 1 mF capacitor. The experimental data confirm that our system can exploit the energy harvested from the cell membrane to communicate wirelessly the temperature and it can be employed in the range of biological interest (30 °C to 50 °C). Such self-powered temperature sensors have the potential to improve the field of biomedical sensing and non-invasive remote temperature monitoring.

Luminescence Thermometry with Nanoparticles: A Review.

Luminescence thermometry has emerged as a very versatile optical technique for remote temperature measurements, exhibiting a wide range of applicability spanning from cryogenic temperatures to 2000 K. This technology has found extensive utilization across many disciplines. In the last thirty years, there has been significant growth in the field of luminous thermometry. This growth has been accompanied by the development of temperature read-out procedures, the creation of luminescent materials for very sensitive temperature probes, and advancements in theoretical understanding. This review article primarily centers on luminescent nanoparticles employed in the field of luminescence thermometry. In this paper, we provide a comprehensive survey of the recent literature pertaining to the utilization of lanthanide and transition metal nanophosphors, semiconductor quantum dots, polymer nanoparticles, carbon dots, and nanodiamonds for luminescence thermometry. In addition, we engage in a discussion regarding the benefits and limitations of nanoparticles in comparison with conventional, microsized probes for their application in luminescent thermometry.

Tb3+/Mn4+ co-doped SrLaMgNbO6 green/red dual-emitting phosphors for optical thermometry

Remote and noncontact surface temperature measurements are frequently required yet challenging to execute. One the most promising options consists in using rare earth or transition metal doped materials as optical (luminescence) temperature sensors. In this paper, a series of novel Tb3+/Mn4+ co-doped SrLaMgNbO6 (SLMN) phosphors have been synthesized and thoroughly investigated for their structural, luminescence spectroscopic and decay kinetics properties as well as for temperature sensing performance. X-ray powder diffraction (XRD) analysis has shown that the prepared sample presents a double perovskite structure. Upon the UV excitation, emission spectra of SLMN:Tb3+, Mn4+ exhibit green and red emission bands for Tb3+ and Mn4+ dopants, respectively. Temperature-dependent photoluminescence (TD-PL) studies revealed sever thermal quenching of Mn4+ emission while that of Tb3+ was moderate providing well pronounced difference in fluorescence intensity ratios (FIR) of the ions. The maximum relative sensitivity (Sr) was found to be 3.27% K−1 and 1.92% K−1 for Mn4+ and Tb3+, respectively. This implies that SLMN: Tb3+, Mn4+ phosphor is a viable candidate material for a dual-mode optical temperature detection.

An optical fiber temperature sensor based on fluorescence intensity ratio in Er3+/Yb3+ co-doped Gd2O3 phosphors

A simple optical fiber temperature sensing system based on up-conversion luminescence of Er3+/Yb3+ co-doped Gd2O3 phosphors is proposed and demonstrated for the first time. The Gd2O3: 1 mol% Er3+, 1 mol% Yb3+ phosphors are synthesized by traditional sol-gel method. A sandwich structure fabricated by two fiber connectors, one of which is deposited the fluorescent material cured with ultraviolet adhesive on the surface, is used as the sensing probe. Temperature measurement is achieved using the two green emissions, generated by Gd2O3: 1 mol% Er3+, 1 mol% Yb3+ phosphors, based on the fluorescence intensity ratio (FIR) technique. When the Gd2O3: 1 mol% Er3+, 1 mol% Yb3+ phosphor is excited by the 980 nm laser with the output power of 73 mW, the intense green emissions are observed and change with temperature. The temperature sensing characteristics are experimentally studied in the temperature range from 253 to 413 K, with the maximum absolute sensitivity of 4.15% K−1 at 413 K, the maximum relative sensitivity of 2.28% K−1 at 253 K and the maximum relative error of 0.43%. The proposed optical fiber temperature sensor not only offers excellent reversibility and stability, but also significantly contributes to accurate and remote temperature measurement in harsh environments.

Non-invasive measurement of the temperature field of a phase change material (PCM) using thermal imaging

This study proposes a novel approach using an infrared camera to remotely measure the internal temperatures of a phase change material (PCM) in a quasi-2D cavity. The remote temperature measurements from the infrared camera were calibrated against a grid of thermocouples embedded in the PCM. The practical cases of experimental melting and freezing of a PCM in a thin circular cavity were used to develop and demonstrate the procedure. The results show good agreement between the infrared and thermocouple techniques in both space and time, confirming that the proposed technique could accurately estimate the PCM temperature remotely without the permanent installation of thermocouples. The method is then demonstrated on a separate experimental setup, using a rectangular geometry and a different PCM. The benefits and limitations of the proposed approach are also discussed.

Thermally enhanced upconversion luminescence of Cr3+ in Er3+-Yb3+-Cr3+ tri-doped garnet phosphors for sensitive optical thermometry

Luminescence thermometry is strongly desired in many fields due to the capability of remote temperature measurement with fast response and high spatial resolution. For developing excellent luminescence thermometer, we systematically investigated the upconversion (UC) emissions from Er3+-Yb3+-Cr3+ tri-doped garnet-structured phosphors under the excitation of 980 nm laser. The influence of Ga3+/Al3+ dopant ratio in Y3Al5-xGaxO12 on the UC luminescence was studied in detail by the X-ray diffraction patterns, Raman spectra, FT-IR spectra and Judd-Ofelt theory. Research revealed that the increase of Ga3+ doping content could reduce the symmetry of rare earth (RE) ions site and simultaneously weaken the nonradiative relaxations, favoring the RE luminescence and the subsequent energy transfer (ET) from RE to Cr3+. More importantly, because of the thermally strengthened ET from Er3+ ions, about 27-fold enhancement in Cr3+ UC luminescence was successfully achieved within Er3+-Yb3+-Cr3+ tri-doped Y3Ga5O12 as temperature ascended from 303 to 873 K, which consequently leaded to the emission color switching in response to temperature change. These advances in the as-prepared garnet phosphors provide potential opportunity for vision-guided temperature sensing with high sensitivity (∼ 4.38% K−1) and low measurement uncertainty (∼ 0.29 K).

МОДЕЛИРОВАНИЕ ЛУННОГО РЕГОЛИТА НА СВЧ

А remote measurement of the lunar regolith temperature from a lander is expected in the near future. A special bench for experimental testing of the experiment details has been created. The test bench simulates the measurement of the temperature of the lunar regolith at depths down to 1 m. The design features and thermal characteristics of the device are considered. The simulator operates at normal atmospheric pressure and provides a temperature drop from 20 to 100 Celsius in a meter-long regolith layer. It is planned to create a test bench that provides operation in a vacuum and a temperature drop from minus 150 to minus 30 Celsius.

Influence of excitation and detection geometry on optical temperature readouts – reabsorption effects in luminescence thermometry

Influence of excitation and detection geometry on optical temperature readouts – reabsorption effects in luminescence thermometry.