Simultaneous Measurement Of Temperature Research Articles

Simultaneous measurement of temperature and refractive index based on fiber optic Fabry–Pérot cavity in batteries

Abstract A Fabry-Pérot (FP) sensor for simultaneous measurement of refractive index and temperature of an all-fiber synchronous liquid based on the Vernier effect is proposed, special application for internal monitoring of lithium-ion battery electrolytes. The theoretical model of high sensitivity cascade Fabry-Pérot interferometer (PFPI) is established, the sensitivity amplification mechanism of PFPI is analyzed in detail, the perfect matching scheme for measuring the refractive index of the electrolyte inside the battery is designed according to the matching conditions of the optical path, and the corresponding sensors for simultaneous measurement of the temperature and the refractive index are fabricated. The experimental results show that the sensor has a maximum refractive index sensitivity of 15391.5033 nm/RIU, a good linear fit, and can effectively monitor the refractive index change of the electrolyte by 10-4 orders of magnitude during normal charging and discharging of lithium-ion batteries. Compared to traditional epoxy adhesive bonded or laser processed FP sensors, this all-fibre optic structure not only improves temperature and corrosion resistance, but also significantly reduces temperature cross-sensitivity. Its small size and excellent resistance to high temperature and corrosion ensure the sensor's excellent response and broad application prospects in monitoring the refractive index of the electrolyte in 18650 lithium-ion batteries, which provides effective technical support for monitoring the health status of batteries and detecting early safety issues.

Simultaneous monitoring of humidity and temperature by polarization volume gratings utilizing responsive cholesteric liquid crystals

Optical sensing devices are utilized for noncontact operation in harsh environments due to their advantage of local separation between the measurement and detector systems. Cholesteric liquid crystals (CLCs) with vivid structural colors are integrated into optical sensors, attracting significant interest for naked-eye detection. To enable vision-based, real-time remote monitoring, we propose a cost-effective method to convert the stimuli-responsive reflection change of CLCs into recordable diffraction patterns using polarization volume gratings (PVGs). This enables real-time remote readout of environmental parameters. PVGs are constructed through holographic polarization interference and photoalignment technologies. The diffraction efficiency of PVGs varies with relative humidity (RH). To improve sensing accuracy and extend the monitoring range of RH, we employ two methods: an orthogonal grating structure and dual-wavelength detection optical path. In addition, we demonstrate the simultaneous measurement of humidity and temperature by cascading independently responding PVGs. We believe that this work will provide a broader perspective and expand the application of light dimensions in LC-based optical sensing.

Simultaneous detection of soot, temperature, and C2H2 in laminar premixed flames using a multi-pass diode laser absorption spectrometer

We report the development of a multi-pass diode laser absorption spectroscopy system for simultaneous measurements of soot volume fraction (SVF), temperature, and C2H2 concentration using a single diode laser near 1.543 µm. A line-shaped beam spot pattern is chosen for the open-path Herriott multi-pass cavity, enabling sensitive detection at various heights above the burner with an effective optical absorption path length of approximately 1.2 m in a 6 cm diameter flame region. The gas parameters (temperature and C2H2 concentration) and the SVF are determined from the absorption spectra of the target C2H2 line pair and the laser extinction of the soot, which can be extracted from the detected signal, respectively. The performance of the system was confirmed in laminar premixed ethylene and air (C2H4/air) sooting flames produced by a standard bronze plug McKenna burner at four representative equivalence ratios. All the measurement results were compared with the two-dimensional (2D) computational fluid dynamics (CFD) simulations using a skeletal mechanism with the Moss−Brookes model. The good quantitative and qualitative agreement between the TDLAS measurements and 2D CFD simulations confirms the powerful capability of the developed system.

Ultrasensitive optical electric field sensor with temperature compensation for point-wise and quasi-distributed sensing.

A point-wise and quasi-distributed optical sensing technique with the Vernier effect is proposed and achieved by multiplexing Fabry-Perot interferometers (FPIs). The FPIs are fabricated by LiNbO3 (LN) crystals of varying lengths to enable simultaneous measurement of electric field (E-field) and temperature. Compared to the traditional bulk-type optical E-field sensors, this innovative sensor enables E-field measurement without being limited by half-wave voltage and effectively avoids the influence of natural birefringence. By an algorithm based on the Fourier transform, sub-FPIs are addressable, and their interference spectra can be demodulated independently, where any two FPIs are paired to generate the fundamental Vernier effect (FVE) or harmonic Vernier effect (HVE). Thus, the measurement sensitivities of FPIs can be significantly improved by monitoring the spectral shift of the envelope in the superimposed spectra. The quasi-distributed sensing experiment is conducted using three cascaded FPIs, yielding E-field sensitivities of 2.84 nm/E (FVE) and 3.37 nm/E (HVE), with a standard deviation (STD) of spectrum variation after temperature compensation below 3.19 × 10-3. The proposed multiplexing method is significant for practical applications of the E-field quasi-distributed measurement.

Wearable and Multiplexed Biosensors based on Oxide Field-Effect Transistors.

Wearable sensors designed for continuous, non-invasive monitoring of physicochemical signals are important for portable healthcare. Oxide field-effect transistor (FET)-type biosensors provide high sensitivity and scalability. However, they face challenges in mechanical flexibility, multiplexed sensing of different modules, and the absence of integrated on-site signal processing and wireless transmission functionalities for wearable sensing. In this work, a fully integrated wearable oxide FET-based biosensor array is developed to facilitate the multiplexed and simultaneous measurement of ion concentrations (H+, Na+, K+) and temperature. The FET-sensor array is achieved by utilizing a solution-processed ultrathin (≈6nm thick) In2O3 active channel layer, exhibiting high compatibility with standard semiconductor technology, good mechanical flexibility, high uniformity, and low operational voltage of 0.005V. This work provides an effective method to enable oxide FET-based biosensors for the fusion of multiplexed physicochemical information and wearable health monitoring applications.

MZI-based high intensity responsive sandwiched multi-layer fiber optic humidity sensor

This paper presents a multi-layer optical fiber humidity sensor based on dual-beam Mach-Zehnder interference (MZI) for optical intensity sensitivity. The sensor is fabricated using a large-scale axial offset fusion technique between a multimode fiber (MMF) and an offset hole two-core fiber (OHTC), making it suitable for agricultural and health monitoring applications. The 27 μm axial offset enables tilted light incidence, enhancing environmental sensitivity. With a single-cycle Graphene oxide (GO) coating of approximately 22 nm, the MMF-OHTC structure achieves high humidity sensitivity (0.39 dB/%RH) over the 25 %-80 % RH range with excellent linearity (R2≈0.99). The sensor exhibits stable, rapid response (2.52 s/0.46 s) and low temperature cross-sensitivity (0.06 %RH/°C). When combined with a hollow-core fiber Fabry-Perot interferometer (HCF-FPI), the system allows zero cross-talk simultaneous humidity and temperature measurements, expanding the potential applications of multi-layered structures in multifunctional detection systems.

Simultaneous measurement of temperature and C2H4 concentration in hydrocarbon flames using interference-immune differential absorption spectroscopy at 3.3 μm

In diagnostic applications based on tunable diode laser absorption spectroscopy, the measurement of target substances can be influenced by factors such as background thermal radiation in the combustion environment, extinction caused by solid or liquid particles, and other interfering absorptions. In this work, we developed a differential absorption diagnostic technique based on wavelength pairs, utilizing an interband cascade laser near 3.3 μm to simultaneously measure temperature and C2H4 concentration in hydrocarbon flames. Based on a detailed study of the C2H4 spectrum in this region and considering the optimal standard for spectral lines, two wavelength pairs were selected. The temperature is determined by the ratio of the absorption cross-sections of two wavelength pairs, and the C2H4 concentration is inferred based on the wavelength pair with higher differential absorption. In the initial stage, the system’s accuracy was verified in high-temperature static conditions (T = 300–800 K, P = 1 atm), and continuous time series measurements demonstrated the system’s stability. The limit of detection achieved by Allan-Werle variance analysis is 2.5 ppm at the optimal average time of 100 s. Subsequently, measurements were taken in a hydrocarbon flame. The obtained results indicate an average deviation of 1.021 % between the measured temperature in the flame and the reference value, with a standard deviation of 1.381 % for concentration measurement. All the measurements show that the system can be potentially applied to combustion diagnosis.

Highly sensitive push-pull differential pressure sensor with multi-parameter measurement capabilities

A multi-parameter sensor comprising of a Fabry–Perot (FP) pair and a fiber-optic FP microcavity was proposed for simultaneous measurement of differential pressure (DP), static pressure (SP) and temperature. The push-pull FP pair is used to measure the differential pressure, and wide measurement range can be achieved by adjusting the dimensions of the diaphragm. The self-enclosed fiber-optic microcavity is utilized to measure the static pressure. For multi-parameter measurement, a matrix equation is proposed to solve the differential pressure, static pressure and temperature by fully considering the relationship of the FP cavity lengths and measurands. The performance of multi-parameter sensing is verified experimentally. The sensitivities of differential pressure, static pressure and temperature are 294.4822 nm/KPa, 353.08 nm/MPa and 42.4056 nm/°C, respectively, in variation of cavity lengths. The sensing characteristics show good linearity. Such a sensor could find important applications in the fields of process industry and oil industry, etc.

An ultrafast optical sensor for simultaneous detection of NH3 temperature and concentration based on ultraviolet absorption spectral redshift combined with spectral reconstruction

As a renewable and carbon-free fuel with high energy density, ammonia (NH3) is a promising alternative to fossil fuels. Real-time detection of its temperature and concentration is significant in improving NH3 combustion efficiency. In this paper, we report an optical sensor, which enables simultaneous measurement of temperature and concentration of NH3. The key idea is to acquire the temperature of NH3 through absorption spectral redshift, and determine its concentration by building three-dimensional field map combined with spectral reconstruction. Firstly, we explain the generation mechanism of temperature-induced redshift in ultraviolet differential absorption spectrum based on energy level distribution theory. The relationship between spectral redshift and temperature is then established using spectral autocorrelation algorithm. Secondly, a spectral reconstruction method based on absorbed intensity mapping wavelength is proposed to ensure real-time detection of NH3. Finally, a three-dimensional field map between temperature, reconstruction slope, and concentration is constructed to achieve the detection. Results indicated that the mean relative error in temperature measurement was 1.04% and the mean absolute error in concentration detection was 0.26mg/m3 in air. Additionally, the NH3 sensor enabled long-term detection with a detection limit of 15.50μg/m2, demonstrating its potential to broaden the application of NH3 as a fuel.

Sensing performance comparison for temperature and liquid level sensor based on uniform and step-Etched microfiber TFBG

By using the hydrofluoric acid uniform-etching and step-etching methods, a tilted fiber Bragg grating (TFBG) microfiber structure was fabricated, where the cladding diameter of the traditional TFBG was reduced to micrometer scale. The temperature sensing characteristics of the uniform-etched and step-etched microfiber TFBGs were experimentally studied and compared. The core mode of its transmission spectrum was used for sensing the temperature change; while the normalized area of cladding modes has been used for real-time monitoring the liquid level. The simultaneous measurement of temperature and liquid level has been experimentally demonstrated for the proposed microfiber TFBG. By combining the strong evanescent field of microfiber and the unique structural advantages of TFBG, the proposed microfiber TFBG has a great potential in developing the miniature optical fiber sensors.

Transverse magnetic field effects on diamond quantum sensor for EV battery monitor

Key implementation points for achieving full accuracy in simultaneous temperature and magnetic field measurement and linearity when applying diamond quantum sensors to electric vehicle (EV) battery monitors were investigated. Both the static and busbar current magnetic field are required to be aligned to the NV-axis. If misalignment should exist, the resonance frequency midpoint move in the direction opposite to the temperature change under a large busbar current due to the transverse magnetic field effect. Misalignment could be quantified with an accuracy of ±1° by analysing the resonance frequency midpoint change under a current of ±1,000 A. The transverse magnetic field effects compensation estimated from misalignment, confirmed that the resonance frequency midpoint changed consistently with temperature changes. Furthermore, linearity over a wide dynamic range also improved. Moreover, it will contribute to accurate alignment of the two sensors for differential detection to eliminate external noise as common mode. These are expected to expand the application of diamond sensors for high-precision measurement in a wide dynamic range.

Error Analysis and Experimental Research of Temperature/Strain Sensing Based on Few-Mode Fiber Bragg Grating

ABSTRACT To solve the temperature/strain cross-sensitivity problem, simultaneous measurement of temperature and strain can be achieved by using the two spectra of LP01 mode and LP11 mode in few-mode fiber Bragg grating (FM-FBG). However, in the same fiber the temperature/strain sensitivity difference is small, so the sensing accuracy is limited greatly. In this paper, we calculate the relation between sensing accuracy and sensitivity-difference and obtain that the enlarged sensitivity difference could improve the sensing accuracy. FBGs are engraved on two kinds fibers single-mode (SM) and few-mode (FM) with different geometrical dimensions; the sensing coefficients of LP01 mode in SM-FBG and LP11 mode/LP01 mode in FM-FBG are calibrated firstly and then are used to sense the temperature/strain. The experimental results show that parallelly using LP01 mode in SM-FBG and LP11 mode in FM-FBG achieves simultaneous measurement of temperature and strain, and error is reduced greatly compared with the sensing results using LP11 mode and LP01 mode in FM-FBG or using LP01 mode in SM-FBG and LP01 mode in FM-FBG, where the wavelength-temperature/strain coefficient difference is maximum. The temperature measurement error is 1.64°C, and the strain measurement error is 20.04 με, which is consistent with the theoretical analysis. The sensing results provide technical reference for FBG multi-parameter sensing measurement and the practical engineering application.

Simultaneous Measurement of Knuckle Flexion and Temperature With a Few-Mode FBG

Simultaneous Measurement of Knuckle Flexion and Temperature With a Few-Mode FBG

Application of Cr-N and Fe-Pd Thin Films to Tactile Sensors for Simultaneous Strain and Temperature Measurement

Application of Cr-N and Fe-Pd Thin Films to Tactile Sensors for Simultaneous Strain and Temperature Measurement

Simultaneous Temperature and Strain Measurement in Fiber Bragg Grating via Wavelength-Swept Laser and Machine Learning

Simultaneous Temperature and Strain Measurement in Fiber Bragg Grating via Wavelength-Swept Laser and Machine Learning

Simultaneous measurement of temperature and pressure sensing technology based on double cavity matching in batteries

A compact sensor based on fiber Fabry-Pérot (FP) cavities dual-cavity matching technique cascaded with fiber Bragg grating (FBG) is proposed and demonstrated to measure pressure and temperature variations inside battery. The sensitivity amplification mechanism for two-parameter measurements is analyzed and a cased reference chamber scheme is designed. Low-cost, small-size, high-temperature and corrosion-resistant all-fiber-optic high sensitivity gas pressure sensors targeting the interior of energy storage batteries are fabricated and cascaded with FBGs to measure temperature parameters. The experimental results show that the sensor has a sensitivity of −26.8322 nm/MPa in a pressure range of 1.86 MPa, the gas pressure inside the battery and the temperature inside and outside the battery at different discharge rates of 1500mAH capacity monobloc batteries can be measured practically, directly and instantly. It has potential applications in detecting subtle pressure variations caused by gas precipitation inside the battery and in temperature measurement, and provides a new concept and a feasible technological path for the measurement of key parameters inside lithium-ion batteries.

Simultaneous measurement of temperature and strain by cascaded fiber Bragg grating-silicon Fabry-Perot interferometer sensor

Simultaneous measurement of temperature and strain by cascaded fiber Bragg grating-silicon Fabry-Perot interferometer sensor

Perpendicular Electrical Conductivity in the Topside Ionosphere Derived from Swarm Measurements

The study of the physical properties of the topside ionosphere is fundamental to investigating the energy balance of the ionosphere and developing accurate models to predict relevant phenomena, which are often at the root of Space Weather effects in the near-Earth environment. One of the most important physical parameters characterising the ionospheric medium is electrical conductivity, which is crucial for the onset and amplification of ionospheric currents and for calculating the power density dissipated by such currents. We characterise, for the first time, electrical conductivity in the direction perpendicular to the geomagnetic field, namely Pedersen and Hall conductivities, in the topside ionosphere at an altitude of about 450 km. For this purpose, we use eight years of in situ simultaneous measurements of electron density, electron temperature and geomagnetic field strength acquired by the Swarm A satellite. We present global statistical maps of perpendicular electrical conductivity and study their variations depending on magnetic latitude and local time, seasons, and solar activity. Our findings indicate that the most prominent features of perpendicular electrical conductivity are located at low latitudes and are probably driven by the complex dynamics of the Equatorial Ionisation Anomaly. At higher latitudes, perpendicular conductivity is a few orders of magnitude lower than that at low latitudes. Nevertheless, conductivity features are modulated by solar activity and seasonal variations at all latitudes.

A novel method to establish friction coefficient model for numerical simulation of inertia friction welding

The precise friction coefficient at interface determines the friction behavior in inertia friction welding (IFW), its model is the basis to precisely describe the friction behavior in the numerical simulation of IFW. To measure the friction coefficient related to the temperature, pressure, and sliding velocity, the IFW trials between 2219-O Al alloy and 304 stainless steel were conducted with the simultaneous measurement of temperature and angular velocity evolutions. Two types of friction coefficient models were established by considering whether the effects of temperature and friction pressure were independent. The S-(T&P) L model, which considered the couple effect of temperature and friction pressure, was recommended as the best suitable model with its very high accuracy and best simplicity. The proposed model was successfully used in simulating the temperature evolution of IFW between Al alloy and steel tubes. The effect of the influencing variables on the friction coefficient was also discussed.

Towards Understanding and Control of Thermal Processes in Lithium-Ion Batteries

Despite lithium-ion batteries (LIBs) being state-of-the-art commercial rechargeable batteries, there are still significant challenges. For example, heat generation during cycling can lead to performance degradation and safety issues1-2. During the process of charging and discharging, the heat that is generated from the chemical reactions taking placing is ideally distributed uniformly in space, to dissipate out the cell easily. However, in practice, heat generation tends to be heterogeneous throughout the battery, leading to localized overheating3. This phenomenon can result in e.g. decomposition of the solid-state electrolyte interphase (SEI) layer, triggering electrode reactions with the electrolyte and degradation of the electrolyte (producing combustible gases) and even melting of the separator4. Hence, comprehending the origins of temperature generation and its heterogeneity is crucial.To address this challenge, operando X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are applied to monitor the structural changes in the electrode materials during charge and discharge, while simultaneous temperature measurements are conducted using a thermal camera, as such obtaining spatial resolved structure/temperature/performance relationships. We have focused on state-of-the-art nickel rich NMC (Nickel Manganese Cobalt Oxide) versus graphite batteries and by comparing the structural changes of the electrode materials during cycling in ‘hot’ versus ‘cool’ areas of the electrode and battery, we were able to establish a structure-temperature relationships, on top of the electrochemical structure-performance relationships and as such unravel “heat-generation” process and reactions. The real-time temperature distribution was compared to the computational models using COMSOL, and insights in thermal processes and their possible control measures could be obtained.References Lain, M. & Kendrick, E. Understanding the limitations of lithium-ion batteries at high rates. Journal of Power Sources. Volume 493, 229690 (2021).Ma, S., et al. Temperature effect and thermal impact in lithium-ion batteries: A review. Progress in Natural Science: Materials International. Volume 28, Issue 6, Pages 653-666 (2018).Rafael, M., et al. Operando Radiography and Multimodal Analysis of Lithium–Sulfur Pouch Cells—Electrolyte Dependent Morphology Evolution at the Cathode. Adv. Energy Mater. 2103432 (2022).Joris, J., et al. A comprehensive review of future thermal management systems for battery electrified vehicles. Journal of Energy Storage 31, 101551(2020).