Temperature Measurement Error Research Articles

A copula-based statistical method of estimating production profile from temperature measurement for perforated horizontal wells

Estimating production profile from temperature data is of great significance for production increase and cost reduction in well production process. This study aims to provide a cost-effective direct method of interpreting flow profiles from temperature measurements. The concept of representative inspired by randomized distribution regarding heat conduction representative points for each no-influx section is proposed. Three assumptions regarding existence, distribution and independence of representatives are introduced to establish a copula-based statistical method of converting fitted distributions of representative, to distributions of relaxation distances for each no-influx section, and then to estimate the production profile. The method is applied on a horizontal gas well on the east slope of western Sichuan depression, and the simulated results are compared with the production logging data. The error of estimators for each no-influx section is between 6.7% and 11.8%, which is satisfactory. Sensitivity analyses are conducted regarding temperature measurement error, and the results verify the robustness of this method. This paper provides a reliable solution to interpret production profile from relatively inaccurate temperature data when the perforation zones are adjacently close. The findings of this study can help for better understanding of low-cost production allocation and uncertain flow state modeling problems.

Errors of non-contact temperature measurement

In recent years, there is a trend of improving the performance and efficiency of all existing measuring instruments due to a leap in technology. Almost every industry uses a variety of technologies that apply temperature control. Temperature of a heated body can be estimated by measuring the parameters of its thermal radiation, which are electromagnetic waves of different lengths. Temperature measurement is necessary for comfortable automatic control and management of production processes. The use of non-contact means makes it possible to measure the temperature of, firstly, moving objects, secondly, objects in inaccessible places, thirdly, to avoid damage to the measuring instruments when controlling large temperatures. High speed, the possibility of measuring temperature without disconnecting the object from the technological process, ensuring personnel safety, temperature measurement up to 3000 °C – these are the advantages of non-contact temperature measurement method. To obtain reliable values when measuring thermophysical quantities it is necessary to know the processes occurring in interaction of the measuring device or sensor with the object of measurement. These processes affect the magnitude of the measurement error, that is, magnitude of the result deviation from the true value of the measured parameter. This paper describes the errors of non-contact temperature measurement of pyrometers, namely total radiation pyrometer, partial radiation pyrometer, spectral ratio pyrometer, as well as shows the results of comparative calculations between them. Expressions for the evaluation of methodical errors of total radiation, partial radiation and spectral ratio pyrometers are given, as well as the results of comparative calculations of errors are shown.

FBG temperature measurement error compensation method based on LSTM and attention mechanism

Real-time temperature measurement of power cables is an important part of the power system, and improving the accuracy of temperature measurement is a key factor of the temperature measurement system. The measurement of existing measurement methods is susceptible to interference and has certain errors. In this paper, an error compensation model is established by using a two-layer LSTM network to view the dynamic error in the process of FBG temperature measurement, and the attention mechanism is used to capture the relevant parameters of temperature change, so as to improve the model effect. The experimental results show that the compensation effect of the two-layer LSTM-Focus model is increased by 44.4% compared with the single LSTM model, which can meet the actual measurement requirements.

Research on ERS point registration of large-size measurement field based on neural network non-uniform temperature field

PurposeLarge size of aircraft assembly tooling structure and complex measurement environment exist. The laid enhanced reference points (ERS) are subject to a combination of nonuniform temperature fields and measurement errors, resulting in increased measurement registration errors. In view of the nonuniform temperature field and measurement errors affecting the ERS point registration problem, the purpose of this paper is to propose a neural network-based ERS point registration compensation method for large-size measurement fields under a nonuniform temperature field.Design/methodology/approachThe approach is to collect ERS point information and temperature data, normalize the collected data to complete the data structure design and complete the construction of the neural network prediction model by data training. The data learning is performed to complete the prediction model construction, and the prediction model is used to complete the compensation analysis of ERS points. Finally, the algorithm is verified through experiments and engineering practice.FindingsExperimental results show that the proposed neural network-based ERS point prediction and compensation method for nonuniform temperature fields effectively predicts ERS point deformation under nonuniform temperature fields compared with the conventional method. After the compensation analysis, the registration error is effectively reduced to improve registration accuracy. Reducing the combined effect of environmental nonuniform temperature field and measurement error has apparent advantages.Originality/valueThe method reduces the registration error caused by combining a nonuniform temperature field and measurement error. It can be used for aircraft assembly site prediction and registration error compensation analysis, which is essential to improve measurement accuracy further.

Adaptive Compensation Method for the Infrared Temperature Measurement Error Based on 3-D Thermal Imaging

Infrared thermal imager can provide two-dimensional temperature information of the measured object on-line without contact, which is one of the most commonly used temperature measurement methods. However, the measuring distance and viewing angle between the thermal imager and the measured object will cause the infrared temperature measurement error. In order to automatically compensate for the temperature measurement error caused by measuring distance and viewing angle when the infrared thermal imager is applied in actual measurement scenarios, this paper proposes an adaptive compensation method for the infrared temperature measurement error based on 3D thermal imaging. Firstly, based on the polynomial regression and infrared temperature measurement principle, a compensation model is established to compensate for the temperature measurement error caused by measuring distance and viewing angle. Secondly, the parameters of the compensation model are determined by using a blackbody furnace and a reference cylinder. Then, a 3D thermal imaging system is constructed with a depth camera and an infrared thermal imager to quantify the measuring distances and viewing angles between all temperature pixels and the thermal imager. Finally, the surface temperature of the measured object can be adaptively compensated using the established compensation model. The experimental results of the blackbody furnace and resin cylinder show that the proposed method can adaptively compensate for the infrared temperature measurement error caused by measuring distance and viewing angle.

THEORETICAL RESEARCHES OF THE EMBEDDED FIBER-OPTIC SYSTEM OF TESTING DEFORMATION AND TEMPERATURE OF POLYMER COMPOSITES

This article describes the results of theoretical researches of the system of optical testing of polymer composites by the method of two optical fibers with different sensitivity to deformation and temperature, using integrated arrays of fiber Bragg gratings. The features of the primary data processing from the optical testing system embedded into the composite are considered by the methods of weighted arithmetic mean and approximation by the Gaussian function. The basic relations for calculating the error in determining the temperature and strain with the help of fiber-optic embedded testing systems are obtained. A numerical model of the interrogator has been constructed, which makes it possible to estimate the systematic error of deformation and temperature measurements, including taking into account the noise of a real interrogator. It is shown that, taking into account a number of assumptions for the problem of simultaneous embedded testing of composites with fiber Bragg gratings, it is advisable to apply he method of primary processing of testing data using the approximation of the real spectra of fiber Bragg gratings by the Gaussian function, while in order to increase the reliability of testing, it is necessary to take into account the temperature correction characteristic of a particular interrogating device.

Influence of Phosphor Saturation on 2-D Temperature Measurement in Phosphor- Converted LEDs by Microscopic Hyperspectral Imaging

We perform an experimental study on the impact of phosphor saturation on 2-D temperature measurement for InGaN/GaN-based phosphor-converted light-emitting diodes (pc-LEDs). These pc-LEDs generally consist of 455-nm InGaN/GaN-based blue LEDs and 623-nm CaAlSiN <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{3}}$</tex-math> </inline-formula> :Eu <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\text{2}+}$</tex-math> </inline-formula> -based red phosphors. The advanced microscopic hyperspectral imaging system is used to monitor 2-D phosphor saturation in these used pc-LEDs. At the same time, this technique can also be used to detect 2-D surface temperature distribution in red pc-LEDs after determining the relationship between surface temperature and temperature-sensitive parameter such as the normalized emission intensity of phosphors and relevant coefficients in their linear relationships. For the ease of analysis, we propose a factor for describing phosphor saturation in pc-LEDs, which is, namely, by phosphor saturation factor (PSF). Then, the influence of phosphor saturation on temperature measurement errors based on PSF is also analyzed. Finally, we believe that this work can provide a useful guidance for experimental understanding of 2-D photo-thermal characteristics in such type of pc-LEDs, which would be extensively applied in future lighting and display fields.

Noninvasive measurement of temperature for simulated tissue based on piezoelectric micromachined ultrasonic transducers

This paper reports a noninvasive measurement of temperature for simulated tissue based on an AlN piezoelectric micromachined ultrasonic transducer array. Polydimethylsiloxane and a built-in heating plate are used to simulate the thermal therapy of human tissue. Based on time-of-flight (ToF) from the simulated tissue surface to the heating plate surface and corresponding temperature data, the piecewise linear fitting method is used to fit the ToF-temperature curve, and its sensitivity is (below 50 °C) and (from 50 °C to 65 °C). The average error of real-time temperature measurements is 0.58 °C for temperatures below 65 °C. The proposed method can provide a good solution for temperature detection during thermal therapy.

Express-diagnostics of the properties of ЫРЫ materials using chrono-topographic analysis of thermal vision data

Subject of research: the article is devoted to the development of a methodology for express diagnostics of material properties based on the measurement of macrokinetic parameters of the SHS process.&#x0D; Purpose of research: plotting the dependence of the microhardness of SHS products on the propagation velocity of the SHS wave and its temperature.&#x0D; Methods and objects of research: the research objects were the SHS process in the Ni-Al system and the reaction products; To measure the propagation velocity of a high-temperature synthesis wave, an original method of chrono-topographic analysis of thermal imaging data was used; temperature control was carried out by an original method of spectral-brightness pyrometry. The study of the microhardness of experimental samples was carried out using an FM-800 microhardness tester.&#x0D; Main results of research: in the course of experimental studies, it was shown that the error in determining the propagation velocity of the SHS wave by the method of chrono-topographic analysis of thermal imaging data is 0.1 %, and the error in temperature measurement by the method of spectral-brightness pyrometry is estimated at 0.5 %. It is concluded that the main factor influencing the total error in the SHS wave propagation velocity in the experiment is the inaccuracy of setting the charge parameters for a set of samples. The absolute value of the total error was 3.2 %. A diagnostic trajectory has been constructed that makes it possible, based on the SHS propagation rate and reaction temperature, to evaluate the microhardness of the product and draw a conclusion about the quality of charge preparation for the production of a material with desired properties.

ВПЛИВ ОПТИЧНИХ ХАРАКТЕРИСТИК ОБ’ЄКТА ТА ПІРОМЕТРИЧНОЇ СИСТЕМИ НА ПОХИБКИ ОПОСЕРЕДКОВАНИХ ВИМІРЮВАНЬ ВИПРОМІНЮВАЛЬНОЇ ЗДАТНОСТІ ТА ТЕМПЕРАТУРИ

The present article aims to study the influence of the optical characteristics of a thermometered object and a pyrometric system on measurement errors of emissivity and temperature. The analysis and classification of factors that determine methodical and instrumental measurement errors have been performed. The expressions which determine the complex multifactorial influence of object and system optical characteristics on methodical and instrumental errors have been derived. On the base of obtained expressions, the influence of the optical characteristics of a thermometered object and a pyrometric system on these errors is analyzed. The dominant influence of the optical characteristics of a thermometered object on methodical errors of emissivity and temperature measurements has been established. The influence of a system`s optical characteristics on methodical errors of emissivity and temperature measurements has been studied under conditions of wide and real thermometered object characteristics ranges of changes. As a result, a significant reduction of methodical errors was achieved by optimizing the optical characteristics of the system. Under conditions of fixed object characteristics and operating wavelengths of a system, the influence regularities of primary pyrometric information errors (operating wavelengths setting and one-color radiation temperatures measurements) on the instrumental errors have been obtained. A significant influence of the signs and modules of primary pyrometric information errors on them has been established. Instrumental errors are minimal in the case of identical signs of primary pyrometric information errors for all operating waves, and maximum in the case of different signs for the middle and boundary waves. With the same signs and modules of one-color radiation temperatures measurement errors, the instrumental error of temperature measurements does not exceed their modules. Keywords: temperature, spectral distribution of emissivity, two-color compensative thermometry, linear method, methodical and instrumental components of measurement error.

Smart wearable flexible temperature sensor with compensation against bending and stretching effects

Flexible and stretchable temperature sensors have recently gained much attention due to their lightweight, thin profile, and ability to adapt to curved or irregular surfaces. Resistive temperature detectors (RTD) are one of the most commonly used sensors for temperature measurement. However, the major challenge with developing RTDs on flexible substrate is that the resistance not only changes with temperature, it also varies with mechanical deformation of the substrate, which can lead to significant errors in temperature measurement. In this paper we propose a novel flexible temperature sensor that can compensate for the deformation-induced resistance variation and measure temperature with minimum errors. The sensor is composed of two RTDs fabricated back-to-back on a polydimethylsiloxane (PDMS) substrate via stencil printing. The dual RTD configuration provides compensation against mechanical deformation caused by bending and stretching. When the sensor is bent on a curved surface, the resistances of the two RTDs change differentially due to tension on one RTD and compression on the other. As a result, the sum of resistance of both RTDs, RSum, remains a constant. Similarly, the subtraction of resistance of the two RTDs, RSub, can be used to compensate for the linear resistance change in sensor stretching. With the compensation methods in place, the sensor can be used for temperature measurement with enhanced accuracy. In addition, the sensor is connected to a Bluetooth-integrated microcontroller which is programmed to determine whether the sensor is undergoing bending or stretching. The compensation methodology can provide reliable measurement for a maximum radius of 40 mm when the sensor is bent or a maximum strain of 3% when it is stretched. The compensation method enhances the competence of flexible temperature sensors and increases their potential for applications in wearable electronics.

Multimodal operation of printed electrochemical transistors for sensing in controlled environment agriculture

The global demand for food is the highest it has ever been due to the growing population and changing diets. This is happening at a time when agricultural production is extremely vulnerable to the changing climate and loss of arable land. Controlled environment agriculture (CEA) is a technology-based approach to grow plants indoors, which drastically reduces land and water use while sustaining high yields. To maintain optimal growing conditions, CEA agronomists need to continuously monitor the environmental parameters surrounding the roots of their crops. Here, we present a low-cost, fully screen printed sensor strip that can be used to measure three essential factors in CEA hydroponic fluids: the electrical conductivity (EC), temperature and pH. By utilizing both DC and AC biasing techniques, we demonstrate how a simple electrochemical transistor can exhibit multimodal sensing functionality. This printed device has a high sensitivity to EC of ∼ 8.7 mA/dec, a < 4 % error for temperature measurement and a Nernstian pH sensitivity of ∼ 59.3 mV/dec. We show that the flexible device can be used to monitor the key environmental growth factors in an active hydroponic growing system over 72 h. The results demonstrate that simple printed electronic (PE) sensing devices can be used effectively to enable precision CEA.

Synthesis of Pyrope Garnet with High Samarium Content at 5 GPa and 1300 °C

In natural garnets associated with diamonds, an increased content of "light" rare-earth elements, especially samarium, is often noticed. There are various estimates of the composition of the crystallization medium. Experimental data on the synthesis of Cr-rich garnets containing rare-earth elements are still scarce. The experiments were carried out on a multi-anvil apparatus of the “split-sphere” type (BARS) at a pressure of 5 GPa and a temperature of 1300 °С. The high pressure cell was made of Zr02 and CaO. A tubular graphite element was used as a heater. The measurement error of pressure and temperature was ± 0.2 GPa and ± 25 °С. The starting materials for the experiments were natural serpentine-antigorite, chromium spinel, and corundum. As a result of the experiments, pyrope crystals with a high content of samarium were synthesized in the range of 0.77 to 2.34 wt% Sm2O3. The study demonstrates that the interaction of components in the serpentine-chromite-corundum-Sm system in the presence of fluid leads to crystallization of pyrope garnet with samarium content exceeding the values known for natural garnets associated with diamond.

Spectrum characteristics and temperature measurement error of FBG sensor based on rotor temperature monitoring system

For real-time temperature monitoring of a generator or electric motor rotor, the effects of rotation on the reflection spectrum of a polyimide-coated Fibre Bragg Grating (FBG) were analyzed using formulas. The measurement error resulting from the low-speed operation was evaluated, combined with the finite element method. Secondly, the key design of the FBG sensors and the mating part of the fiber optic rotary joint (FORJ) were investigated. The temperature of a rotating shaft was monitored to test the reliability of the measurement system. With a resolution of 0.1℃, the system was able to achieve an error of 0.5℃ over a range of 30-180℃. Finally, the critical conditions for the application of polyimide-coated and metal-coated FBGs were discussed. The results show that the variation of the center wavelength is more sensitive to the radius of the small-sized rotor, and the rotation speed of the large-sized rotor. It is at higher speeds that the thickness of the coating has a more pronounced effect on error, demonstrating that the accuracy of FBGs used in high-speed rotors could be rapidly improved by reducing the thickness of the metal coating. The reported results provide a basis for the thermal monitoring performance of FBG sensors during rotation.

Novel lead-connection technology for thin-film temperature sensors with arbitrary electrode lengths

Traditional thin-film thermocouples (TFTCs) have limitations in measuring real surface temperature changes in aircraft because the connection between the nanofilm and the leads can easily fail. Despite this, how to improve this weak connection has rarely been addressed in previous studies. In this study, a lead-embedded alumina ceramic substrate is proposed to improve the durability of TFTCs. Multi-layer two-dimensional nanofilms with different thin-film electrode lengths were prepared on a substrate using DC-pulsed magnetron sputtering. Furthermore, the effect of the thin-film electrode length on the sensitivity, response time and measurement error of the sensor was investigated. The electrode length did not affect the sensitivity and response time; however, as it was increased, the temperature measurement error decreased. In addition, the static and dynamic performance, repeatability, measurement accuracy and service lifetime of the developed sensor were verified. The results show that the sensor has high sensitivity and linearity and good repeatability, with the response time being in microseconds. The sensor can continue to operate at 500 °C for more than 2 h with no signal interruption. The sensor’s reported accuracy is 0.43% at 300 °C.

Integrated machine learning and probabilistic degradation approach for vessel electric motor prognostics

In the transition towards more sustainable ships, electric motors (EM) are being used in ship propulsion systems to reduce emissions and increase efficiency. The safe operation of ships is crucial, and prognostics and health management applications have emerged as effective solutions to transit towards monitored reliable systems. In this context, this paper presents a probabilistic EM prognostics model integrating data-driven operational models and physics-informed degradation models. Firstly, motor torque and winding temperature are estimated through connected machine learning models, which are based on operational and meteorological data. Operational and meteorological variables drive the EM degradation model and enable the analysis of EM degradation under different operational and environmental conditions. Subsequently, EM remaining useful life (RUL) is predicted within a probabilistic Monte-Carlo approach combining the thermal-stress model along with the associated uncertainties. The methodology is tested on a real case study of the OV Ryvingen vessel, with collected data during voyages along the Norwegian coast. Results confirm the validity of the designed RUL model showing that, under normal operation conditions, the degradation is mild, and the temperature measurement errors are important for RUL estimation.

A wireless demodulation system based on a multi-parameter resonant sensor.

This paper proposes a wireless passive measurement system that supports real-time signal acquisition, multi-parameter crosstalk demodulation, and real-time storage and calculation. The system consists of a multi-parameter integrated sensor, an RF signal acquisition and demodulation circuit, and a multi-functional host computer software. The sensor signal acquisition circuit uses a wide frequency detection range (25 MHz-2.7GHz) to meet the resonant frequency range of most sensors. Since the multi-parameter integrated sensors are affected by multiple factors, such as temperature and pressure, there will be interference between them, so the algorithm for multi-parameter decoupling is designed, and the software for sensor calibration and real-time demodulation is developed to improve the usability and flexibility of the measurement system. In the experiment, temperature and pressure dual-reference integrated surface acoustic wave sensors in the condition of 25-550 °C and 0-700kPa are used for testing and verification. After experimental testing, the swept source of the signal acquisition circuit can meet the output accuracy in a wide frequency range, and the detection result of the sensor dynamic response is consistent with that of the network analyzer, with a maximum test error of 0.96%. Furthermore, the maximum temperature measurement error is 1.51%, and the maximum pressure measurement error is 5.136%. These results indicate that the proposed system has good detection accuracy and demodulation performance, and it can be used for multi-parameter wireless real-time detection and demodulation.

Radiation temperature measuring method with high dynamic range via fast double-exposure image fusion

The CCD (Charge-coupled device) image sensor can invert the surface temperature of the object by collecting the radiation signal of the high-temperature object. It is a non-contact temperature measurement method, which has the characteristics of fast response without affecting the surface distribution of the tested object. Due to the restriction of the development level of CCD, the exposure tolerance of imaging is low. As a result, the temperature field measurement range is low. In order to solve the problem of low exposure tolerance caused by dark current and saturation in CCD, this paper proposes a radiation temperature measuring method with high dynamic range via fast double-exposure image fusion technology, and a high temperature field measurement system based on LabVIEW and visible light industrial camera is developed. The method proposed in this study is suitable for the stationary objects in temperature range from 750 to 1200 ℃. By correcting the non-impulse response of the sensor, the temperature measurement error is better than 2%. By fusing two images with different exposure duration, the dynamic temperature measurement range is increased to 59.2%, which significantly improves the adaptability of the CCD in the measurement of high temperature field.

The Estimated Temperature of the Semiconductor Diode Junction on the Basis of the Remote Thermographic Measurement.

The value of a semiconductor's diode temperature determines the correct operation of this element and its useful lifetime. One of the methods for determining the die temperature of a semiconductor diode is through the use of indirect thermographic measurements. The accuracy of the thermographic temperature measurement of the diode case depends on the prevailing conditions. The temperature of the mold body (the black part of the diode case made of epoxy resin) depends on the place of measurement. The temperature of the place above the die is closer to the die temperature than the temperature of mold body fragments above the base plate. In addition, the difficulty of its thermographic temperature measurement increases when the surface whose temperature is being measured is in motion. Then, the temperature measured by thermography may not apply to the warmest point in the case where the die temperature is determined. Information about the difference between temperatures of the different parts of the mold body and the die may be important. For this reason, it was decided to check how much the temperature measurement error of the die diode changes if the temperature of the diode case is not measured at the point that is above the die.

Dual-Population Social Group Optimization Algorithm Based on Human Social Group Behavior Law

Inspired by the behavior law of human social groups, a new swarm intelligence algorithm named the dual-population social group optimization (DPSGO) algorithm is proposed in this article. Based on the primitive social group optimization (SGO) algorithm, dual-population grouping technology, reverse learning technology, immigration migration technology, and Gaussian mutation are introduced to further simulate the behavior law of actual human social groups. Experimental results and performance comparison show that the DPSGO algorithm has a better searchability and convergence rate. In addition, aiming at the socially hot issue of aviation safety, the simulation and experimental results show that the temperature measurement error can be reduced to less than 7.5 °C by using the DPSGO algorithm combined with reflected radiation correction to process the aeroengine multispectral radiation temperature measurement data. This article is of great significance to the design and optimization of swarm intelligence algorithms by using the behavior law of human social groups and provides valuable guidance for enhancing the safety monitoring of aeroengines.