scholarly journals Calibration and verification of streaked optical pyrometer system used for laser-induced shock experiments

2019 ◽  
Vol 7 ◽  
Author(s):  
Zhiyu He ◽  
Guo Jia ◽  
Fan Zhang ◽  
Xiuguang Huang ◽  
Zhiheng Fang ◽  
...  
Keyword(s):  
Single Channel ◽  
Temperature Measurements ◽  
Color Temperature ◽  
Optical Pyrometer ◽  
Measured Temperature ◽  
Laser Facility ◽  
Standard Value ◽  
Temperature Standard ◽  
Different Color ◽  
Standard Lamp

Although the streaked optical pyrometer (SOP) system has been widely adopted in shock temperature measurements, its reliability has always been of concern. Here, two calibrated Planckian radiators with different color temperatures were used to calibrate and verify the SOP system by comparing the two calibration standards using both multi-channel and single-channel methods. A high-color-temperature standard lamp and a multi-channel filter were specifically designed for the measurement system. To verify the reliability of the SOP system, the relative deviation between the measured data and the standard value of less than 5% was calibrated out, which demonstrates the reliability of the SOP system. Furthermore, a method to analyze the uncertainty and sensitivity of the SOP system is proposed. A series of laser-induced shock experiments were conducted at the ‘Shenguang-II’ laser facility to verify the reliability of the SOP system for temperature measurements at tens of thousands of kelvin. The measured temperature of the quartz in our experiments agreed fairly well with previous works, which serves as evidence for the reliability of the SOP system.

ACCURACY OF OPTICAL PYROMETRY IN THE RANGE 800 °C TO 4000 °C

1958 ◽  
Vol 36 (10) ◽  
pp. 1397-1408 ◽  
Author(s):  
D. R. Lovejoy
Keyword(s):  
Standard Deviation ◽  
Temperature Scale ◽  
Primary Standard ◽  
Secondary Standard ◽  
Optical Pyrometer ◽  
Optical Pyrometry ◽  
International Temperature Scale ◽  
International Temperature ◽  
Carbon Arc ◽  
Temperature Standard

A pair of secondary standard tungsten strip lamps have had a luminance temperature – current calibration, in the range 800 °C to 2200 °C, at a number of national laboratories. An analysis of the calibration results confirms estimates of the accuracy of optical pyrometry in the range 800 °C to 2200 °C and supports the extension of these estimates to 4000 °C. The standard deviation uncertainty of optical pyrometry is shown to be about 1 °C at 800 °C rising to 2 °C at 2200 °C and 10 °C at 4000 °C, being about double this for the calibration of commercial pyrometers unless certain described precautions are taken.The reliability of the secondary standard lamps, when used under well-defined conditions, is confirmed and it is shown that they have a standard deviation calibration uncertainty of about 1 °C for the vacuum-type lamps in the range 800 °C to 1500 °C and 2 °C for the gas-filled lamps in the range 1500 °C to 2200 °C. Most of this uncertainty is due to primary standard optical pyrometer calibration errors. Attention is drawn to the fact that a carbon arc fulfills the requirements of a secondary luminance temperature standard at about 3514 °C.Recent determinations of the gold point and the second radiation constant indicate that the 1948 International Temperature Scale is lower than the thermodynamic scale by an amount varying from 0.8 °C at 800 °C to 12 °C at 4000 °C. This is already greater than the calibration errors of optical pyrometry and, in view of the still greater accuracies presaged by photomultipliers, a revision of the International Temperature Scale is suggested.

scholarly journals Thermal Conductivity of High Performance Concrete in Wide Temperature and Moisture Ranges

10.14311/174 ◽  
2001 ◽  
Vol 41 (1) ◽  
Author(s):  
J. Toman ◽  
R. Černý
Keyword(s):  
Thermal Conductivity ◽  
High Performance ◽  
Room Temperature ◽  
High Performance Concrete ◽  
Measuring Method ◽  
Point Of View ◽  
Temperature Measurements ◽  
Temperature Fields ◽  
Measured Temperature ◽  
Hot Wire

The thermal conductivity of two types of high performance concrete was measured in the temperature range from 100 °C to 800 °C and in the moisture range from dry material to saturation water content. A transient measuring method based on analysis of the measured temperature fields was chosen for the high temperature measurements, and a commercial hot wire device was employed in room temperature measurements of the effect of moisture on thermal conductivity. The measured results reveal that both temperature and moisture exhibit significant effects on the values of thermal conductivity, and these effects are quite comparable from the point of view of the magnitude of the observed variations.

Ion temperature measurements of indirect-drive implosions with the neutron time-of-flight detector on SG-III laser facility

2018 ◽  
Vol 89 (2) ◽  
pp. 023504 ◽  
Author(s):  
Zhongjing Chen ◽  
Xing Zhang ◽  
Yudong Pu ◽  
Ji Yan ◽  
Tianxuan Huang ◽  
...  
Keyword(s):  
Time Of Flight ◽  
Temperature Measurements ◽  
Ion Temperature ◽  
Laser Facility ◽  
Indirect Drive ◽  
Neutron Time

Modeling Reservoir Temperature Transients and Reservoir-Parameter Estimation Constrained to the Model

2010 ◽  
Vol 13 (06) ◽  
pp. 873-883 ◽  
Author(s):  
Obinna O. Duru ◽  
Roland N. Horne
Keyword(s):  
Flow Rate ◽  
Oil And Gas ◽  
Mechanistic Model ◽  
Operator Splitting ◽  
Temperature Data ◽  
Temperature Measurements ◽  
Solution Technique ◽  
Measured Temperature ◽  
Reservoir Temperature ◽  
Temperature Transient

Summary Permanent downhole gauges (PDGs) provide a continuous source of downhole pressure, temperature, and sometimes flow-rate data. Until recently, the measured temperature data have been largely ignored, although a close observation of the temperature measurements reveals a response to changes in flow rate and pressure. This suggests that the temperature measurements may be a useful source of reservoir information. In this study, reservoir temperature-transient models were developed for single- and multiphase-fluid flows, as functions of formation parameters, fluid properties, and changes in flow rate and pressure. The pressure fields in oil- and gas-bearing formations are usually transient, and this gives rise to pressure/temperature effects appearing as temperature change. The magnitudes of these effects depend on the properties of the formation, flow geometry, time, and other factors and result in a reservoir temperature distribution that is changing in both space and time. In this study, these thermometric effects were modeled as convective, conductive, and transient phenomena with consideration for time and space dependencies. This mechanistic model included the Joule-Thomson effects resulting from fluid compressibility and viscous dissipation in the reservoir during fluid flow. Because of the nature of the models, the semianalytical solution technique known as operator splitting was used to solve them, and the solutions were compared to synthetic and real temperature data. In addition, by matching the models to different temperature-transient histories obtained from PDGs, reservoir parameters such as average porosity, near-well permeabilities, saturation, and some thermal properties of the fluid and formation could be estimated. A key target of this work was to show that temperature measurements, often ignored, can be used to estimate reservoir parameters, as a complement to other more-conventional techniques.

scholarly journals Developing a multi-spectral imaging system using a RGB camera under two illuminations

2020 ◽  
Vol 2020 (28) ◽  
pp. 277-281
Author(s):  
Zhen Liu ◽  
Kaida Xiao ◽  
Michael Pointer ◽  
Changjun Li
Keyword(s):  
Imaging System ◽  
Estimation Method ◽  
Spectral Imaging ◽  
Color Temperature ◽  
Lighting Conditions ◽  
Model Combining ◽  
Rgb Images ◽  
Spectra Properties ◽  
Different Color ◽  
Specular Highlights

This paper proposes a multi-spectral imaging system, developed using a commercial-grade camera, under two commonly used illumination. Rather than using conventional direct or diffuse light, the novelty of our method is to use a cross-polarized imaging system to eliminate glare and specular highlights. Two RGB images are captured under two different color temperature lighting conditions. An improved reflectance estimation method is developed to transform camera RGB under two illumination to spectral reflectance using a regulated model, combining the polynomial expansion of the camera signals with optimally selected feature. The method was tested using both a semi-gloss ColorChecker SG (140) and matte ColorChecker DC (240) chart. The results indicate that the proposed method significantly outperforms the traditional methods both in terms of spectra and colorimetric accuracy. This new multi-spectral imaging system is sufficiently precise to predict spectra properties and its performance within an acceptable range.

Temperature Measurements with Depth and Physical Evidence for the Effect of High Temperature Gradients on Top-Down Fatigue Cracking

2020 ◽  
Vol 2674 (4) ◽  
pp. 384-396
Author(s):  
Adrian Ricardo Archilla
Keyword(s):  
High Temperature ◽  
High Surface ◽  
Fatigue Cracking ◽  
Time Of Day ◽  
Temperature Gradients ◽  
Temperature Measurements ◽  
Measured Temperature ◽  
Horizontal Shear ◽  
Top Down ◽  
Shear Strains

This paper presents the results of pavement temperature measurements with depth over a year obtained with a setup emulating the heat flow on a pavement with 305 mm (12 in.) of hot mix asphalt (HMA) and 152 mm (6 in.) of aggregate base. Several findings related to top-down fatigue cracking (TDFC) in Hawaii were obtained from these measurements. It was observed that pavement temperatures near the surface, which were both the lowest and the highest in the HMA depending on the time of day, were rarely below 20°C, and thus, that most cracking in Hawaii occurs at higher temperatures. It was also observed that passing rains can cause sudden temperature drops of the order of 15°C within short periods (15 min). HMA moduli estimated using measured temperature profiles indicate that high temperature gradients may lead to inverted moduli profiles that when loaded cause the highest tensile and shear strains to occur near the surface, and that these may be a main reason for TDFC in the state. The simulated stresses and strains under high temperature gradients also indicate they may be conducive to delamination problems related to large horizontal shear strains generated near the surface and combined with nearly vertical but small tensile strains at the layer interface. The observation that cracking suddenly and consistently stops under overpass bridges and immediately resumes after them provides strong evidence consistent with the findings of the stress/strain distributions generated from profiles with high surface temperature and high temperature gradients potentially causing TDFC. The paper provides recommendations for further study.

AN INVESTIGATION OF THE MACBETH ILLUMINOMETER

1948 ◽  
Vol 26f (2) ◽  
pp. 59-65 ◽  
Author(s):  
W. E. Knowles Middleton ◽  
A. R. Ramsey
Keyword(s):  
Color Temperature ◽  
Working Standard ◽  
Standard Lamp

The MacBeth illuminometer is a well known portable photometer of the visual type. Measurements of its errors show that the instrument gives reliable results if used with care. The most serious errors may occur when the color temperature of the light that is being measured differs greatly from that of the working standard lamp in the instrument. Under such conditions, different observers may obtain widely different results.

Sign in / Sign up

Export Citation Format

Share Document