Infrared Radiation Thermometer Research Articles

準静的および衝撃圧縮変形時の<i>β</i>型チタン合金の強度と温度上昇

Titanium alloy is one of the typical aerospace structural materials because of its lightness, high specific strength, and high corrosion resistance. However, it has extremely low thermal conductivity, too. This causes relatively high temperature rise due to the heat converted from plastic work, especially under impact loading. In this study, a series of compression tests for β-titanium alloy in the wide ranges of testing temperature (77K∼673K) and strain rate (3.3 × 10-4∼103s-1) was carried out to investigate the effect of the heat generation on the mechanical properties. The temperature rise of the specimen during impact compression tests was measured by an infrared radiation thermometer with a photoconductive element. The conversion ratio of plastic work into heat βh was also examined at temperatures of 201K∼473K. The principal results obtained are as follows: The temperature rise of specimen during plastic deformation at 201K is greater than that observed at room temperature (298K) and at 473K. The conversion ratio βh is not necessarily to be constant, i.e. βh is less than 0.1 in the early plastic deformation and gradually increases up to around 0.7 with the increase of plastic deformation at 298K. The increase of βh at lower temperature is more drastic.

The Temperature Measurement Method Based on the Image of Mechanical Part during Heating Treatment

The mechanical part was heated to the heat treatment temperature, and the surface color changed with temperature. The infrared radiation thermometer was used to get heating part temperature, and the corresponding color images were taken by the camera at the same time. The program was designed to analyze the images and display the temperature. To decrease the effect of the noise disturbance in the process of image, the combined filter method was used. The relationship between the temperature and image of heating mechanical parts were obtained through digital regression. The analysis and comparison results show that the temperature measurement precision of three primary color is higher than gray’s from 700°C to 1100°C. The three primary colors have more information for image recognition than that of gray image, and are suitable for higher technical requirements.

Research on the Array Type Infrared Radiation Thermometer

In recent years, infrared temperature-measuring attracted more and more attention from home and abroad. Infrared temperature-measuring is non-contact and does not destroy the temperature distribution of the measured target object. At present, infrared radiation thermometer (point thermometer) and thermal infrared imager are wildly used. They both have advantages and disadvantages. The array type infrared radiation thermometer discussed in this paper contains the advantages of IR thermometer and thermal infrared imager and could measure the multi-point of the target’s surface simultaneously and accurately. Its basic principle is to obtain array processing to the infrared detector, simultaneously measure the multi-point temperature of the objects, take the measured object as a benchmark to calibrate infrared radiation thermometer so as to solve the problem of radiation rate fixed difficulties and improve accuracy of radiation temperature measurement.

Investigation on the precipitation behavior of M 3C phase in T91 ferritic steels

As traditional 9–12% Cr heat-resistant ferritic steels, T91 steels have been considered as candidate reduced-activation materials for nuclear engineering applying due to its excellent creep resistance and high resistance to void formation during neutron irradiations at elevated temperature. Needle-like M 3C precipitates are produced during the routine normalizing process before tempering. Differential scanning calorimetry and infrared radiation thermometer have been employed to study the precipitation behavior of the secondary M 3C particles upon subsequent cooling process after austenization. Various austenization conditions (holding time, temperature and the subsequent cooling rate) were carried out to clarify effect of normalizing condition on the formation of the M 3C phase. In spite of various austenization conditions applied, it is found that the precipitation of M 3C phase is depends only on the cooling rate applied. Furthermore, the precipitation of M 3C phase occurs before the onset of the martensite transformation, which is contrary to the previous statement that it takes place during the auto-tempering stage after martensitic transformation. The above observation points out that the precipitation of M 3C would produce an effect on the subsequent martensitic transformation behavior, leading to the formation of wide martensite laths with a low dislocation density.

High resolution thermo-radiative modeling of an urban fragment in Marseilles city center during the UBL-ESCOMPTE campaign

The thermodynamic exchanges of the old city center of Marseilles during a summer period are analyzed with the SOLENE thermo-radiative model, using measurements of the UBL-ESCOMPTE experimental campaign in June–July 2001. The selected scene is an actual fragment of the urban canopy composed of 4 streets at right angles, with various 19th century houses and yards. The SOLENE software’s ability to simulate the heat and radiation exchanges of this urban district with the atmosphere is first evaluated by comparing simulation outputs with surface temperatures of individual roof and façade elements measured by infrared radiation thermometers and with integrated fluxes measured on top of a neighboring meteorological mast. This model assessment is reinforced by a sensitivity study to the interior building temperature, a variable of possible influence which is usually not measured in studies at the scale of an urban fragment or district. The flux sensor position influence on the comparison is also studied by introducing a virtual sensor in the simulated scene. The software is further used to analyze the behavior of individual surface elements of the scene with various orientations during a typical summer diurnal cycle. The contributions of the different surface classes (roofs, façades, streets, yards) to the upward radiation and heat fluxes to the atmosphere are then detailed for several canopy morphologies (H/W).

Calibration of Thermocouples and Infrared Radiation Thermometers by Comparison to Radiation Thermometry

The National Metrology Institute of Spain (CEM) has designed, characterized, and set-up its new system to calibrate thermocouples and infrared radiation thermometers up to 1600 °C by comparison to radiation thermometry. This system is based on a MoSi2 three-zone furnace with a graphite blackbody comparator. Two interchangeable alumina tubes with different structures are used for thermocouples and radiation thermometer calibrations. The reference temperature of the calibration is determined by a standard radiation thermometer. Normally, this is used at CEM to disseminate the International Temperature Scale of 1990 (ITS-90) in the radiation range, and it refers to the Cu fixed point. Several noble metal thermocouples and infrared radiation thermometers with a central wavelength near 900 nm have been calibrated, and their uncertainty budgets have been obtained.

Experimental Study of Explosive Water Mist Extinguishing Fire

Explosive water mist extinguishing fire is a method in which using the energy of explosion to push and disperse water into water mist to extinguish fire. Compared with the present ways of suppressing fire such as water mist fire suppressing system, water dropped by helicopters and so on, explosive water mist extinguishing fire has the merits of high efficiency in extinguishing fire, can be used far away from fire and so on, therefore it has a bright applying prospect in the field of suppressing forest fire and grassland fire suppression etc.. In this paper, interaction between explosive water mist and fire was investigated, temperature variations during the interaction were obtained by thermocouple and infrared radiation thermometer respectively, and photos during the interaction were taken by a DV Digital Video. Moreover, characteristic parameters of explosive water mist were calculated, interaction mechanism between explosive water mist and fire was analyzed. It is showed that effect of explosive water mist on fire roots in shock waves and explosive water mist, the former works in a complicated way for strong shock waves suppress combustion but weak shock waves work on the contrary. Explosive water mist suppresses combustion forcefully by mechanism of lower the temperature and insulating oxygen in order to asphyxiate, etc.. Besides, explosive water mist has comparatively large momentum, which enables it pass through smoke to act on the surface of fuel, because of its big velocity.

Emissivity Correction for the Wall Temperatures Measured by Infrared Radiation Thermometers in a Hot Tunnel, Kurobe

Emissivity Correction for the Wall Temperatures Measured by Infrared Radiation Thermometers in a Hot Tunnel, Kurobe

Thermal transport in CO2 laser irradiated fused silica: In situ measurements and analysis

In situ spatial and temporal temperature measurements of pristine fused silica surfaces heated with a 10.6 μm CO2 laser were obtained using an infrared radiation thermometer based on a mercury cadmium telluride camera. Laser spot sizes ranged from 250 to 1000 μm diameter with peak axial irradiance levels of 0.13–16 kW/cm2. For temperatures below 2800 K, the measured steady-state surface temperature is observed to rise linearly with both increasing beam size and incident laser irradiance. The effective thermal conductivity estimated over this range was approximately 2 W/m-K, in good agreement with classical calculations based on phonon heat capacities. Similarly, time-dependent temperature measurements up to 2000 K yielded thermal diffusivity values which were close to reported values of 7×10−7 m2/s. Above ∼2800 K, the fused silica surface temperature asymptotically approaches 3100 K as laser power is further increased, consistent with the onset of evaporative heat losses near the silica boiling point. These results show that in the laser heating regime studied here, the T3 temperature dependent thermal conductivity due to radiation transport can be neglected, but at temperatures above 2800 K heat transport due to evaporation must also be considered. The thermal transport in fused silica up to 2800 K, over a range of conditions, can then be adequately described by a linear diffusive heat equation assuming constant thermal properties.

Simulation and Experimental Study on Temperature Fields for Laser Assisted Machining of Silicon Nitride

Laser assisted machining (LAM) is an effective method machining difficult-to-machine materials such as ceramics which uses a high power laser to focally heat a workpiece prior to material removal with a traditional cutting tool. A laser assisted machining experiment system was set up and a transient, three-dimensional heat transfer model was developed for LAM of silicon nitride using Finite Element Method to understand the thermal process of laser heating. The model was based on temperature-dependent thermophysical properties and the heat generated was neglected due to cutting which is assumed to be small compared to the heat generated by laser heating. The experiments were carried out to investigate the effects of operating parameters, such as laser power, laser translational speed, rotational speed, laser beam diameter and preheating time on temperature distribution. An infrared radiation thermometer was used to measure the surface temperature histories and the experimental results were in good agreement with predictions. The laser power and laser translational speed have the greatest influence on the temperature.

Effect of electromagnetic field strength on Ni0.35Zn0.65Fe2O4 as performed by combustion synthesis

Ni0.35Zn0.65Fe2O4 ferrite is prepared through combustion synthesis in the external electromagnetic field. The highest magnetic field strength for the experiment is 1.1T. Reactions temperatures were monitored by infrared radiation thermometer, the synthesized ferrite prepared in different magnetic fields is analyzed by XRD, SEM, and VSM. The results indicate that the coercivity of ferrite gradually decrease with the increase of magnetization. When the magnetic field strength is 0.54T, the saturation magnetization is improved up to 56.05emu/g (42%) as compared to that of ferrite in zero magnetic field. Through SEM analysis of Ni0.35Zn0.65Fe2O4 ferrite, homogeneous grains of the crystal are observed. With the increase of external magnetic field, the ferrite grain improved. This paper also systematically explores the effect of the electromagnetic field on ferrite by combustion synthesis.

Measurement of Emissivity of Water Vapor Adsorbents with Infrared Radiation Thermometer

Measurement of Emissivity of Water Vapor Adsorbents with Infrared Radiation Thermometer

マウスの社会的接触場面における体表面温度の変化

We investigated physiological and behavioral characteristics of socially stressed animals in a resident-intruder paradigm. ICR male mice (resident, n = 14) were exposed individually to a novel male conspecific (intruder, n = 14) in their homecage for 30 min. Along with behavioral analyses, the skin temperatures of both the resident and the intruder were measured simultaneously using a multipoint radiation thermometer. There were no significant differences between the resident and intruder in the amount of locomotion, flight and aggressive behaviors. The mean skin temperature of the residents during the interaction was higher than before the interaction. In addition, the skin temperatures of the intruders were consistently higher than the residents. The results suggest that social stress causes elevation in skin temperature as well as stress-induced hyperthermia in core temperature. Moreover, infrared radiation thermometers may provide an alternative means of measuring physiological parameters of two (or more) subjects simultaneously in the study of animal social behavior.

The Influence of Distance and Focus on the Calibration of Infrared Radiation Thermometers

If a radiation thermometer is calibrated by measuring the temperatures of two cavities having different geometries, sometimes discrepancies arise between them, even though their emissivities are close to that of a blackbody. The origin of such discrepancies may result from the size-of-source effect, and in the distance-to-target effect for those thermometers that offer focusing capability. Examples include: (a) out-of-focus image changes the reading: different focus settings produce different results and (b) measurements taken at different distances produce different results. These effects are discussed, their contribution to the measurement uncertainty is evaluated, and some recommendations are made for practical blackbody cavities or radiators to reduce such effects.

Middle Temperature Scale for Infrared Radiation Thermometer Calibrated Against Multiple Fixed Points

The NMIJ has established a temperature scale for infrared radiation thermometry from 100 to 420°C consisting of three fixed-point blackbodies at the In, Sn, and Zn points and an InSb detector thermometer at a wavelength of 4.7 μm. The blackbody cavities have large openings of 15 mm diameter. The expanded uncertainties (k = 2) of the In, Sn, and Zn fixed-point radiance temperatures are estimated to be 0.03, 0.03, and 0.05 K, respectively. The expanded uncertainties (k = 2) for the calibration of the infrared radiation thermometer are estimated to be 0.04 K at 157°C (In point), 0.04 K at 232°C (Sn point), and 0.07 K at 420°C (Zn point).

A Vacuum Infrared Standard Radiation Thermometer at the PTB

A thermal infrared radiation thermometer was jointly developed by the Physikalisch-Technische Bundesanstalt and Raytek GmbH for temperature measurements from − 150°C to 170°C under vacuum. The radiation thermometer is a purpose-built instrument to be operated with the PTB reduced-background infrared calibration facility. The instrument is a stand-alone system with an airtight housing that allows operation inside a vacuum chamber, attached to a vacuum chamber, and in air. The radiation thermometer will serve to calibrate thermal radiation sources, i.e., blackbody radiators, by comparing their radiance temperature to that of a variable-temperature reference blackbody inside the reduced-background calibration facility. Furthermore, since it can be operated under vacuum and in air, the instrument also allows the water- and ammonia-heat-pipe reference blackbodies of the PTB low-temperature calibration facility operated in air to be compared with the variable-temperature blackbody operated under vacuum. Finally, provided that sufficient long-term stability is achieved, the instrument shall be used as a transfer radiation thermometer to carry and compare the temperature scale of PTB by means of radiation thermometry to remote-sensing calibration facilities outside PTB. The mechanical, optical, and electrical designs of the instrument are reported. Results of investigations on the temperature resolution, size-of-source effect, and the reference function are given. The heat-pipe blackbodies operating in air are compared to the variable-temperature blackbody operated under vacuum by using the vacuum radiation thermometer.

Radiative Properties of Blackbody Calibration Sources:Recent Advances in Computer Modeling

The radiative characteristics (spectral effective emissivity, spectral radiance, and radiance temperature) of blackbody calibration sources widely used in radiation thermometry are an important subject for advanced computer modeling by the Monte Carlo method. An algorithm and code for stochastic modeling of the radiant heat transfer inside cavities has been developed on the basis of the reciprocity principle and backward ray tracing. The importance sampling technique has been applied to generate the reflected rays according to the surface reflection model that can be a linear combination of the following primary models: Lambertian, Specular, and TETRA (a microfacet model of random tetrahedral pits that mimics reflections from a rough surface). A wide range of axisymmetrical cavities, cylindrical cavities with an inclined flat bottom, and a rectilinear grooved radiator of polygonal profile have been implemented. Various conditions of observation can be modeled to compute appropriate radiation characteristics. A number of different temperature distributions can be assigned to the same node set on the cavity surface, so several related tasks can be modeled in a single run. The results obtained for the radiative properties of isothermal and non-isothermal non-diffuse blackbodies used for the calibration of infrared radiation thermometers are presented and discussed.

暑熱時の屋外におけるサフォーク種めん羊の体表面温度

The body surface temperature of a Suffolk sheep placed outside under summer heat was measured using infrared radiation thermometer. The sheep was sheared only left side of the body. The surface temperature at the top of the head showed high temperature by exposing to the direct rays of the sun, indicating 62.5°C on 14 : 00 of August 1st (highest temperature ; 31.8°C). Simultaneously, the temperature at the top of the topline wool (wool length ; about 10 cm) indicated 44.5°C, while the temperature at the bottom of the topline wool was nearly body temperature.The result indicates that the preparation of sunshade like shelter tree will be very important on grazing under summer heat because the surface temperature at the top of the head of Suffolk sheep covered with black short hair will become high temperature by exposing to the direct rays of the sun, and that wool has excellent insulating effect for summer heat.

Estimation of Drought Tolerance Based on Leaf Temperature in Upland Rice Breeding

The evaluation of drought tolerance based on the leaf temperature was examined in upland rice breeding. The relationships of the leaf temperature with the transpiration and photosynthetic rates were observed in upland and lowland rice varieties under upland cultivation in 1995, 1996 and 1997. The leaf temperature of the upland rice varieties was lower than that of the lowland rice varieties. Their transpiration and photosynthetic rates were highly correlated with the leaf temperature, measured using an infrared radiation thermometer or portable photosynthesis gas analyzing system in all the three years. The leaf temperature also showed a significant relationship with the grain yield tested in 1995. It is considered that rice varieties with a lower leaf temperature can maintain high transpiration and photosynthetic rates as well as produce a high yield under upland conditions. In addition, there was a significant positive correlation between the leaf temperature and root growth recorded by the trench method. Upland rice varieties with deep rooting showed lower leaf temperatures than those with a shallower root system. On the other hand, in the comparison of leaf temperature in varietal groups of breeding materials, the upland rice lines with medium-late maturity showed the lowest temperature, followed by the early maturing lines and lines for cultivation with sprinkler irrigation. This tendency was in agreement with the general degree of drought tolerance of individual varietal groups. To analyze the mode of inheritance of the leaf temperature, the parent-offspring correlation of leaf temperature measured using an infrared radiation thermometer was examined in breeding materials. Leaf temperature was compared between the progeny lines (F4 generation) of the upland rice variety Kantomochi168 with a high drought tolerance and the upland rice variety Norinmochi4 with a medium drought tolerance. Kantomochi168 progeny showed a lower leaf temperature than Norinmochi4. A similar tendency was confirmed in the F5 generation in the following year. Significant parental-offspring correlation (r = 0.812**) was observed between F4 and F5. Since the leaf temperature of the upland rice progeny may display a relatively higher inheritance, the leaf temperature is, therefore, considered to be a useful indicator to estimate the drought tolerance for line selection in upland rice breeding.

High-Speed Infrared Radiation Thermometry for Microscale Thermophysical Property Measurements

A new infrared radiation thermometer having a high temporal response and a high spatial resolution is being developed at NMIJ to meet the existing demand for measurements of thermophysical properties of thin films, coatings, and solids in microscale. The thermometer consists of a photovoltaic (pv)-type of mercury cadmium telluride (MCT) detector and a compact Cassegrain type of mirror optics without a mechanical chopper. The performance of the thermometer has been well characterized experimentally. Sensing infrared radiation around 10 μm of wavelength, the thermometer covers the temperature range from −50 to 150°C and has a temperature resolution better than 0.3°C at −50°C for blackbody radiators. The spatial resolution has also been checked by using a test pattern (USAF 1951) for rating the resolution of optical systems. Temperature changes of specimen surfaces in periodic heating with a laser beam modulated above 100 kHz have been observed successfully with the thermometer. The results shows that the thermometer has great potential for measuring the thermal diffusivity, thermal conductivity, and specific heat capacity of microscale substances at low temperatures based on the periodic heating and pulsed laser heating methods.