Infrared Radiation Thermometer Research Articles

Crop water stress index characterizes maize productivity under water and salt stress by using growth stage-specific non-water stress baselines

ContextThe use of non-destructive, continuous, and rapid canopy temperature (Tc) indices for crop stress diagnosis is of significant importance for improving crop water productivity (WP). However, the comprehensive applicability of the crop water stress index (CWSI), grounded in Tc, in diagnosing both single and combined water and salt stress, as well as characterizing physiological and growth traits, remains inadequately explored. ObjectiveWe aim to investigate the ability of CWSI to diagnose single and combined water and salt stress and to test whether a non-water stress baseline (NWSB) with or without growth stage and genotype differences influences CWSI to characterise maize leaf physiological and growth traits. MethodsHere, we measured the Tc using infrared radiation thermometers of two maize genotypes (XY335 and ZD958) under both single and combined water and salt stress over two growing seasons, compared the differences of NWSB in three growth stages, and established CWSI. Our analysis involved scrutinizing the differences in characterizing crop physiology and growth traits between CWSI calculated using NWSB with and without growth stage differentiations. ResultsOur findings indicated that Tc is modulated by an interplay of soil water content, VPD, and soil salinity. The NWSB exhibited variations with both growth stage (pslope < 0.001) and genotype (pslope or pintercept < 0.01). The CWSI can diagnose single and combined water and salt stress suffered by maize. Under no stress, and single and combined water and salt stress, CWSI was significantly correlated with stomatal conductance (R2 ≥ 0.31, p < 0.1) and net photosynthetic rate (R2 ≥ 0.38, p < 0.1), rather than with hydraulic traits. The mean CWSI across the entire growth period closely correlated with leaf area index (LAI), canopy photosynthetically active radiation interception, biomass, yield, and evapotranspiration across varying treatments (R2 ≥ 0.54, p < 0.1). Contrary to CWSI derived from NWSB without growth stage variations, utilizing CWSI with growth stage distinctions better characterized physiological traits, while the former was more suitable for delineating yield and WP. ImplicationsThis research underscores the efficacy of CWSI for stress diagnosis and the evaluation of gas exchange and productivity in maize under both single and combined soil water-salt stress. This investigation significantly propels forward the implementation of crop-centric irrigation strategies aimed at optimizing water utilization efficiency.

InAsSb Photodiode Fibre Optic Thermometry for High-Speed, near-Ambient Temperature Measurements

Infrared radiation thermometers (IRTs) overcome many of the limitations of thermocouples, particularly responsiveness and calibration drift. The main challenge with radiation thermometry is the fast and reliable measurement of temperatures close to room temperature. A new IRT which is sensitive to wavelengths between 3 μm and 11 μm was developed and tested in a laboratory setting. It is based on an uncooled indium arsenide antimony (InAsSb) photodiode, a transimpedance amplifier, and a silver halogenide fibre optic cable transmissive in the mid- to long-wave infrared region. The prototype IRT was capable of measuring temperatures between 35 °C and 100 °C at an integration time of 5 ms and a temperature range between 40 °C and 100 °C at an integration time of 1 ms, with a root mean square (RMS) noise level of less than 0.5 °C. The thermometer was calibrated against Planck’s law using a five-point calibration, leading to a measurement uncertainty within ±1.5 °C over the aforementioned temperature range. The thermometer was tested against a thermocouple during drilling operations of polyether ether ketone (PEEK) plastic to measure the temperature of the drill bit during the material removal process. Future versions of the thermometer are intended to be used as a thermocouple replacement in high-speed, near-ambient temperature measurement applications, such as electric motor condition monitoring; battery protection; and machining of polymers and composite materials, such as carbon-fibre-reinforced plastic (CFRP).

A novel PZT-based high-power piezoelectric vibrator for ultrasonic motors: properties enhanced by Yb institution

PurposeThe electrical properties of piezoelectric vibrators have a crucial influence on the operating state of ultrasonic motors. In order to solve the problem that the current piezoelectric vibrator generates a large amount of heat during vibration to degrade its performance, which in turn affects the normal operation of ultrasonic motors, this paper prepares a novel piezoelectric vibrator and tests its maximum vibration velocity under the working condition, which is more than twice as much as that of the current commercial PZT-8.Design/methodology/approachThe crystal structures of the samples were analyzed by using an X-ray diffractometer. For microstructure observation, samples were observed by scanning electron microscope (SEM). The quasi-static piezoelectric coefficient meter (ZJ-3AN) was used for piezoelectric measurement. Dielectric properties were measured by utilizing an impedance analyzer (Agilent 4294A) with a laboratory heating unit. Ferroelectric hysteresis loops were obtained using a ferroelectric analyzer (Radiant, Multiferroic 100). A Doppler laser vibrometer (Polytec PSV-300F, Germany) and a power amplifier were used for piezoelectric vibration measurements, during which the temperature rise was determined by an infrared radiation thermometer (Victor 303, China).FindingsThe ceramics exhibit enhanced piezoelectric performance at 0.1–0.4 mol% of Yb doping contents. The ceramic of 0.4 mol% Yb reaches the maximal internal bias field and presents a larger mechanical quality factor of 1,692 compared with that of 0.2 mol% Yb-doped ceramic, in spite of a slightly decreased dielectric constant of 439 pC/N, the unit of the piezoelectric constant, which is the ratio of the local charge (pC) to the frontal force (N) and electromechanical coupling coefficient of 0.63. The vibrator with this large mechanical quality factor ceramic displays a vibration velocity of up to 0.81 m/s under the constraint of 20 °C temperature rising, which is much higher than commercial high-power piezoelectric ceramics PZT-8.Originality/valueThe enhanced high-power properties of the piezoelectric vibrator by Yb doping may provide a potential application for the high-performance USM and offer the possibility of long-term stable operation under high power for special equipment like USM. In the subsequent phase of research, the novel PZT-based high-power piezoelectric vibrator can be utilized in the USM, and the motor's performance will be evaluated under aerospace conditions to objectively assess the reliability of the piezoelectric vibrator.

Laboratory evaluation of forehead infrared radiation thermometers (FIRTs) used for core body temperature measurements

Laboratory evaluation of forehead infrared radiation thermometers (FIRTs) used for core body temperature measurements

High-Speed Infrared Radiation Thermometer for the Investigation of Early Stage Explosive Development and Fireball Expansion.

The understanding of blast loads is critical for the development of infrastructure that protects against explosions. However, the lack of high-quality experimental work on the characterisation of such loads prevents a better understanding of many scenarios. Blast loads are typically characterised by use of some form of pressure gauge, from which the temperature can be inferred from a pressure measurement. However, such an approach to temperature measurement is limited; it assumes ideal gas laws apply throughout, which may not be the case for high temperature and pressure scenarios. In contrast, infrared radiation thermometers (IRTs) perform a measurement of temperature based upon the emitted radiance from the target object. The IRTs can measure fast changes in transient temperature, making them seemingly ideal for the measurement of a fireball’s temperature. In this work, we present the use of a high-speed IRT for the measurement of early-stage explosive development and fireball expansion within a confined blast, with the temperature of the explosive fireball measured from its emitted radiance. The temperature measured by the IRT was corroborated against the temperature inferred from a pressure gauge measurement; both instruments measured the same temperature from the quasi-static pressure (QSP) point onwards. Before the QSP point, it is deduced that the IRT measures the average temperature of the fireball over a wide field-of-view (FOV), as opposed to that inferred from the singular shocks detected by the pressure gauge. Therefore, use of an IRT, in tandem with a pressure gauge, provides a potential invaluable measurement technique for the characterisation the early stages of a fireball as it develops and expands.

Laser–particle interaction-based analysis of powder particle effects on temperatures and distortions in directed energy deposition additive manufacturing

In order to investigate the interactions between laser and powder particles in directional energy deposition (DED) additive manufacturing (AM), a coupled electromagnetic wave heating (EWH) model is proposed. The heat transfer reduction coefficient for the laser beam power can be calculated, and then the temperature distributions can be obtained based on the modified heat source model. A comparison of the predicted temperature and that obtained in the experiment using infrared radiation thermometer validates the proposed models. The residual distortion of the additive manufactured specimen was measured in experiment and then studied in detail using the numerical model. The powder quality can affect the number of particles in the laser’s electromagnetic wave, as well as the laser power that a layer of particles absorbs. As a result, it can affect the heat transfer reduction coefficient in DED, along with the thermal histories and temperature distributions. Thus, the final residual distortion can be changed and controlled by the powder. In addition to the powder particle parameters, the thickness of the substrate and location of the deposition layers on the substrate can also significantly influence the residual distortion of the deposition product in DED.

Development of Novel Thermal Diffusivity Analysis by Spot Periodic Heating and Infrared Radiation Thermometer Method.

A spot periodic heating method is a highly accurate, non-contact method for the evaluation of anisotropy and relative thermophysical property distribution. However, accurately evaluating thermal diffusivity is difficult due to the influence of temperature wave reflection from the whole surface of the sample. This study proposes a method to derive thermal diffusivity using a parameter table based on heat transfer equations using the concept of optimum distance between heating-point and measurement point. This method considers finite sample size, sensitivity distribution of infrared ray detector, intensity distribution of heating laser and sample thickness. In these results, the obtained thermal diffusivity of pure copper corresponded well with previous literature values. In conclusion, this method is considered highly effective in evaluating the thermal diffusivity in the horizontal direction.

Zero Drift Infrared Radiation Thermometer Using Chopper Stabilised Pre-Amplifier

A zero-drift, mid–wave infrared (MWIR) thermometer constructed using a chopper stabilised operational amplifier (op-amp) was compared against an identical thermometer that utilised a precision op-amp. The chopper stabilised op-amp resulted in a zero-drift infrared radiation thermometer (IRT) with approximately 75% lower offset voltage, 50% lower voltage noise and less susceptibility to perturbation by external sources. This was in comparison to the precision op-amp IRT when blanked by a cover at ambient temperature. Significantly, the zero-drift IRT demonstrated improved linearity for the measurement of target temperatures between 20 °C and 70 °C compared to the precision IRT. This eases the IRT calibration procedure, leading to improvement in the tolerance of the temperature measurement of such low target temperatures. The zero-drift IRT was demonstrated to measure a target temperature of 40 °C with a reduction in the root mean square (RMS) noise from 5 K to 1 K compared to the precision IRT.

Strain field measurements over 3000 °C using 3D-Digital image correlation

With the development of aerospace and fusion engineering, understanding the mechanical behavior of materials under high-temperature conditions has become increasingly important. However, few studies are devoted to the ultra-high temperature range of 2000–3000 °C. In this study, with the aim of developing non-contact measuring techniques of mechanical deformation under ultra-high temperature, a high heat flux (~300 MW) comprehensive experimental platform is established, which includes a vacuum chamber, a three-dimensional digital image correlation (3D-DIC) system, infrared radiation thermometers and an electron beam heating system. Using the electron beam heating technique, the tungsten specimen can be heated to over 3000 °C. Owing to the use of a vacuum chamber, the thermally induced airflow disturbance at high temperature can be completely removed. Tantalum carbide (TaC) powder is chosen as the speckle material and speckle fabrication technology is developed to adapt ultra-high temperatures under vacuum conditions. In order to suppress the blackbody radiation at high temperature, three schemes based on blue light sources, self-radiating light sources and a dual wavelength optical filter technique are designed for three temperature ranges from room temperature to 3067 °C. Afterwards, full-field thermal deformation of the tungsten specimen above 3000 °C was determined based on the above strategies using the 3D-DIC technique. The feasibility and accuracy of the proposed methods are verified by comparing the measurement results with the thermal expansion strain data and model from available databases and literature. The standard deviations in different temperature intervals are 50 με for 25–1200 °C, 100–200 με for 1200–1800 °C and less than 500 με for 1800–3067 °C. The proposed methods and technologies are expected to lay a foundation for further developments in strain field measurements at ultra-high temperature.

Analysis of the correlation between the extreme temperature of incision surface and non-union of incision in internal fixation of calcaneal fracture

Objective To explore the correlation between the extreme temperature of incision surface and non-union of incision in internal fixation of calcaneal fracture. Methods From January 2016 to December 2017, 142 patients with closed unilateral calcaneal fracture treated with open reduction and internal fixation in the Integrated Chinese and Western Medicine Hospital of Wenzhou were enrolled.The incision temperature was collected by infrared radiation thermometers intermittently for 4-5 times, and the extreme values were used for further analysis.The primary endpoint of the study was the incision healing 14 days after surgeries.The patients′ age, gender, inflammatory indicators and body mass index (BMI) were evaluated, as well as related factors such as diabetes and arteriosclerosis. Results All patients completed the follow-up observation 14 days after operation, and finally achieved the wound healing in 105 cases, and the wound non-healing in 37 cases.The average extreme value of low temperature was (34.91±0.47)℃ in the union group and (34.13±0.60)℃ in the disunion group, and the average extreme value of high temperature was (36.61±0.55)℃ in the union group and (36.90±0.52)℃ in the disunion group, there were statistically significant differences between the two groups(t=7.152, -2.762, P=0.000, 0.007). Logistic regression analysis results showed that age[β(regression coefficient)=-0.111], extreme high(β=2.728) or very low (β=-3.854), arteriosclerosis(β=4.597), history of diabetes(β=2.234) were risk factors for incision nonunion(P=0.046, 0.003, 0.001, 0.002, 0.024). Conclusion Extreme incision temperature is observed to be associated with an increased risk of operative incision disunion after open reduction and internal fixation for calcaneal fractures. Key words: Fractures, bone; Calcaneus; Fracture fixation, internal; Body temperature; Wound healing; Postoperative complications; Logistic models

The Application of a Novel Infrared Temperature Measurement System in HVDC Converter Valve Equipment Connector Overheat Failure Prevention

Converter valve is the most important equipment in HVDC transmission system, but during the operation and maintenance of HVDC projects, electrical connectors overheat failures in converter valve equipments caused several unexpected trip events, which affects the safe and reliable operation of HVDC projects. Portable infrared temperature instrument is effective to surpervise the temperature of eletrical equipments in valve hall and prevent the overheat failure, but it is carried out manually. The electric company arranges oeprators to inspect the temperature of certain important equipments, which requires a lot of labor and has inspection blind aera. Therefore, on line temperature measurement system based on infrared radiation thermometer is proposed. The infrared temperature instrument performance is affected by ambient temperature seriously, in order to improve the accuracy of the measurement, this paper designs a novel infrared temperature measurement system with a silicon temperature sensor device embedde to provide valve hall temperature. This paper introduces the situation of converter valve equipments overheat failure and infrared temperature measurement technology, then a novel infared temperature measurement system applied in converter valve hall is proposed, both hardware and software design are addressed. At last, experiments are carried out to test the performance, which shows the embedded temperature measurement has high accuracy.

Research on H500-Type High-Precision Vacuum Blackbody as a Calibration Standard for Infrared Remote Sensing

Based on the calibration requirements of vacuum low background aerospace infrared remote sensing radiance temperature, a high-precision vacuum blackbody (H500 type) is developed for the temperature range from − 93 °C to + 220 °C at the National Institute of Metrology, China. In this paper, the structure and the temperature control system of H500 are introduced, and its performance, such as heating rate and stabilization of temperature control, is tested under the vacuum and low-background condition (liquid-nitrogen-cooled shroud). At room temperature and atmospheric environment, the major technical parameters of this blackbody, such as emissivity and uniformity, are measured. The measurement principle of blackbody emissivity is based on the control of surrounding radiation. Temperature uniformity at the cavity bottom is measured using a standard infrared radiation thermometer. When the heating rate is 1 °C min−1, the time required for the temperature to stabilize is less than 50 min, and within 10 min, the variation in temperature is less than 0.01 °C. The emissivity value of the blackbody is higher than 0.996. Temperature uniformity at the bottom of the blackbody cavity is less than 0.03 °C. The uncertainty is less than 0.1 °C (k = 2) over the temperature range from − 93 °C to + 67 °C.

Establishment of Comparison Calibration Equipment for Infrared-radiation Thermometers Below 0°C

Establishment of Comparison Calibration Equipment for Infrared-radiation Thermometers Below 0°C

Comparative Study of Two InGaAs-Based Reference Radiation Thermometers

More than one decade ago, an InGaAs detector-based transfer standard infrared radiation thermometer working in the temperature range from \(150\,{^{\circ }}\hbox {C}\) to \(1100\,{^{\circ }}\hbox {C}\) was built at TUBITAK UME in the scope of collaboration with IMGC (INRIM since 2006). During this timescale, the radiation thermometer was used for the dissemination of the radiation temperature scale below the silver fixed-point temperature. Recently, a new radiation thermometer with the same design but with different spectral responsivity was constructed and employed in the laboratory. In this work, we present the comparative study of these thermometers. Furthermore, the paper describes the measurement results of the thermometer’s main characteristics such as the size-of-source effect, spectral responsivity, gain ratio, and linearity. Besides, both thermometers were calibrated at the freezing temperatures of indium, tin, zinc, aluminum, and copper reference fixed-point blackbodies. The main study is focused on the impact of the spectral responsivity of thermometers on the interpolation parameters of the Sakuma–Hattori equation. Furthermore, the calibration results and the uncertainty sources are discussed in this paper.

Influence of Size of Source Effect on Accuracy of LWIR Radiation Thermometers

Abstract Determining the size of source effect of a radiation thermometer is not an easy task and manufacturers of these thermometers usually do not indicate the deviation to the measured temperature due to this effect. It is one of the main uncertainty components when measuring with a radiation thermometer and it may lead to erroneous estimation of the actual temperature of the measured target. We present an empiric model to estimate the magnitude of deviation of the measured temperature with a long-wavelength infrared radiation thermometer due to the size of source effect. The deviation is calculated as a function of the field of view of the thermometer and the diameter of the radiating source. For thermometers whose field of view size at 90% power is approximately equal to the diameter of the radiating source, it was found that this effect may lead to deviations of the measured temperature of up to 6% at 200ºC and up to 14% at 500ºC. Calculations of the temperature deviation with the proposed model are performed as a function of temperature and as a function of the first order component of electrical signal.

Uncertainty of temperature measurements in dry orthogonal cutting of titanium alloys

Infrared radiation thermometer is used to measure the temperature of tool during dry orthogonal cutting of titanium alloys. The accuracy of measured temperature depends on several parameters such as the experimental set-up, physical acquisition data system and physical characteristic of the tool. These parameters are identified, their uncertainty estimated and the way they influence the final temperature discussed.

High-Transmission Filters for Realizing Gray-Body Radiators

Calibration of infrared radiation thermometers at non-unity emissivity settings is a poorly solved problem for establishment of traceability to meet user needs, for instruments with both fixed and variable emissivity setting functions. A variable-temperature gray-body radiator having a constant value of emissivity independent of both wavelength and temperature can be a perfect tool for the calibration purpose. In this paper, two types of high-transmittance optical neutral density filters, one utilizing a rotating-sector optical chopper, and another of a wire-mesh type, are shown to perform well with a precise transmittance between 90 % and 100 % in the wide infrared wavelength range. These optical filters in combination with a blackbody cavity traceable to ITS-90 can realize reliable gray-body radiation. These methods are applied successfully to several models of infrared thermometers operated in the emissivity correction mode.

Adaptability of High-Yielding Rice Cultivars in Relation to Biomass Productivity under Moderately Water Stressed Upland Conditions

Recent studies have focused on the improvement of rice productivity under aerobic conditions for times when water resources and food production are limited. This study aimed to evaluate the adaptability of high-yielding rice cultivars to moderately water-stressed upland conditions in order to contribute breeding. A three-year field experiment in the temperate climate of Kyoto, Japan, indicated that the decrease in yield was mainly derived from a decrease in above-ground total dry matter (TDM) rather than a decrease in harvest index (HI). Although the decrease in TDM was mostly caused by a decrease in radiation use efficiency (RUE), we determined that the key to adapting high-yielding cultivars to upland conditions is intercepted radiation per day (IRPD), governed by leaf area index (LAI). Although the effect was not robust, LAI growth under upland conditions was associated with root length density. RUE was dependent on leaf water potential (LWP), indicating that a plant’s ability to maintain LWP under water-stressed conditions is important. The results also suggest the necessity of a canopy analyzer to evaluate LAI, as well as an infrared radiation thermometer to evaluate RUE. Performing such measurements during breeding efforts allows us to select for genotypes that are suitable for less stressed aerobic conditions.

Ensuring linearity of optical-reception system of infrared radiation thermometer

The need to ensure the linearity of the conversion function of the optical-reception system of the reference radiation thermometer was substantiated in the paper.The technique for ensuring the linearity of the conversion function of the optical-reception system of infrared radiation thermometer was proposed. It is based on the definition of deviations from linearity of conversion function of the optical-reception system of the radiation thermometer in several fixed temperature points, the formation of the temperature dependence of linearity corrections and their introduction into an output signal of the radiation thermometer.The experimental studies, the results of which have allowed to obtain the function of corrections for linearization of the output signal of radiation thermometer for temperature range 0÷419,51 K and spectral band 8÷14 microns were carried out.The proposed methodology is appropriate to apply in certification of reference radiation thermometers for implementing temperature scale transmission to working infrared radiation thermometers based on the Planck radiation law.

Study on Intelligent Control of Laser 3D Rapid Prototyping Based on PMAC

The paper is based on industrial PC with rich application developed resources under Windows environment and openness of PMAC numerical control system. With the consideration of characteristics and specific requirements of laser rapid prototyping, a third party software is developed by Visual C++ in Windows98 to communicate with the slave machine to get some forming parameters in the laser processing under control by calling PCOMM32PRO DLLs which is offered by Delta Tau company. Combining the developed third party software with the infrared radiation thermometer monitoring the real-time temperature of molten pool can improve the forming efficiency of workpiece obviously.