Pyrometric Temperature Measurement in Concentrated Sunlight With Emissivity Determination

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Nathan B. Crane
Keyword(s):  
Temperature Measurement ◽  
Measurement Errors ◽  
Low Cost ◽  
Random Noise ◽  
Temperature Data ◽  
Temperature Measurements ◽  
Solar Furnace ◽  
Surface Emissivity ◽  
Specialized Equipment ◽  
The Difference

Pyrometers are commonly used for high temperature measurement, but their accuracy is often limited by uncertainty in the surface emissivity. Radiation heating introduces additional errors due to the extra light reflected off the measured surface. While many types of specialized equipment have been developed for these measurements, this work presents a method for measuring high temperatures using single color pyrometers when the surface emissivity is unknown. It is particularly useful for correcting errors due to reflected light in solar heating applications. The method requires two pyrometers and is most helpful for improving measurement accuracy of low cost commercial instruments. The temperature measurements of two pyrometers operating at different wavelengths are analyzed across a range of sample temperatures to find the surface emissivity values at each wavelength that minimize the difference in temperature measurements between pyrometers. These are taken as the surface emissivity values, and the initial temperature measurements are corrected using the calculated emissivity values to obtain improved estimates of the surface temperature. When applied to temperature data from a solar furnace, the method significantly decreased the difference in the temperature measurements of two single color pyrometers. Simulated temperature data with both random noise and systematic errors are used to demonstrate that the method successfully converges to surface emissivity values and reduces temperature measurement errors even when subjected to significant errors in the model inputs. This method provides a potential low cost solution for pyrometric temperature measurement of solar-heated objects. It is also useful for temperature measurement of objects with unknown emissivity.

Low-Cost Pyrometric Temperature Measurement in Concentrated Sunlight With Emissivity Determination

2008 ◽  
Author(s):  
Nathan B. Crane
Keyword(s):  
Temperature Measurement ◽  
Narrow Band ◽  
Low Cost ◽  
Random Noise ◽  
Temperature Data ◽  
Temperature Measurements ◽  
Solar Furnace ◽  
Analysis Method ◽  
Reflected Light ◽  
The Difference

A method for correcting pyrometric temperature measurements of high temperature objects with unknown emissivity is presented. The method also estimates surface emissivity a the pyrometer wavelengths. It is particularly useful for correcting errors due to reflected light in solar heating applications. The method requires two or more narrow band pyrometers and can be applied to low-cost commercial instruments. The method analyzes the temperature measurements of multiple pyrometers operating at different wavelengths across a range of sample temperatures to solve for the surface emissivities that minimize the differences in temperature measurements. The temperature measurements are corrected using the new emissivities values. Simulated temperature data with both random noise and systematic errors is used to assess the robustness of the analysis method. When applied to temperature data from a solar furnace, it is shown to significantly decrease the difference in the temperature measurements of two single-color pyrometers. This method provides a potential low cost solution for pyrometric temperature measurement of solar-heated objects.

Transient Temperature Measurement Errors in Heated Slabs for Thermocouples Located at the Insulated Surface

1961 ◽  
Vol 83 (4) ◽  
pp. 505-506 ◽  
Author(s):  
D. R. Burnett
Keyword(s):  
Temperature Measurement ◽  
Measurement Errors ◽  
Wire Diameter ◽  
Temperature Measurements ◽  
Transient Temperature ◽  
Slab Thickness ◽  
Cold Side ◽  
Thermocouple Wire

A method is developed for estimating the error in “cold side” transient temperature measurements of slabs heated at one surface which is due to conduction of heat away from the junction through a thermocouple wire. Results are presented for a range of slab thickness/wire diameter ratios.

Measurement of High Thermodynamic Temperatures in the DLR Solar Furnace by UV-B Detection

Solar Energy ◽  
2002 ◽  
Author(s):  
Nicola Rohner ◽  
Andreas Neumann
Keyword(s):  
Temperature Measurement ◽  
Temperature Measurements ◽  
Solar Furnace ◽  
Correct Selection ◽  
Basic Material ◽  
Atmospheric Conditions ◽  
Spectral Measurements ◽  
System Temperature ◽  
Selection Of

The correct selection of the operating wavelength is essential for a precise pyrometric temperature measurement on solar irradiated samples, as the measurement may be disturbed by reflected solar radiation. Atmospheric conditions and particularly the emissivity as basic material property determine the amount of this reflected and the emitted radiation from a sample under investigation. An approach to solve this problem by using a monochromator system for temperature measurement in the UV-B range was developed and experimentally tested. With this system, temperature measurements were possible beginning at 1320°C and ranging up to about 2400°C. Two calculation methods are described and compared. The influence of the calibration temperature on the quality of the temperature measurement is shown. Measurements on a blackbody up to 1500°C were performed for calibration purpose. Temperature measurements on a real solar heated magnesia sample up to 2400°C are presented and discussed. These spectral measurements on hot bodies irradiated in the DLR Solar Furnace led to the final specification of the measurement wavelengths to be in the range from 280 nm to 293 nm.

scholarly journals Temporal Artery Temperature Measurement in the Neonate

2017 ◽  
Vol 34 (10) ◽  
pp. 1026-1031 ◽  
Author(s):  
Mashette Syrkin-Nikolau ◽  
Karen Johnson ◽  
Tarah Colaizy ◽  
Ruthann Schrock ◽  
Edward Bell
Keyword(s):  
Body Weight ◽  
Temperature Measurement ◽  
Study Design ◽  
Gold Standard ◽  
Temporal Artery ◽  
Temperature Measurements ◽  
Postmenstrual Age ◽  
The Mean ◽  
The Difference

Abstract Objective We compared an infrared temporal artery thermometer with our clinical standard axillary thermometer for temperature measurements in neonatal patients. Study Design We measured temporal artery (Tta), axillary (Tax, clinical standard), and rectal (Tr, gold standard) temperatures of 49 infants. The difference between Tr and Tta was compared with that between Tr and Tax, and the data were analyzed based on bed type and postmenstrual age. Results The mean Tta, Tax, and Tr were 37.16 (SD 0.36) °C, 36.61 (SD 0.30) °C, and 36.82 (SD 0.30) °C, respectively. The measurements by these methods were all significantly different. The mean Tr-Tax was 0.21 (SD 0.26) °C, and the mean Tr-Tta was −0.34 (SD 0.37) °C, indicating that Tax was closer to Tr than was Tta (p < 0.0001). Tta agreed more closely with Tr for infants in cribs than for those in incubators. Adjusting for bed type and body weight, with each week of postmenstrual age, the discrepancy between Tr-Tta and Tr-Tax decreased by 0.005°C (p = 0.034). Conclusion Compared with the gold standard, Tr, Tta is not more accurate than Tax. The temporal artery thermometer was less accurate for infants in incubators than for infants in cribs. The accuracy of temporal artery temperature increased with postmenstrual age.

Building a new high-density air temperature measurement network in two Swiss cities

2021 ◽  
Author(s):  
Julien G. Anet ◽  
Sebastian Schlögl ◽  
Curdin Spirig ◽  
Martin P. Frey ◽  
Manuel Renold ◽  
...  
Keyword(s):  
Temperature Measurement ◽  
Air Temperature ◽  
Heat Waves ◽  
Low Cost ◽  
High Density ◽  
Urban Heat Islands ◽  
Temperature Measurements ◽  
Heat Islands ◽  
Urban Heat ◽  
The City

&lt;p&gt;With progressive climate change, weather extremes are very likely to become more frequent. While rural regions may suffer from more intense and longer drought periods, urban spaces are going to be particularly affected by severe heat waves. This urban temperature anomaly, also known as &amp;#8220;urban heat island&amp;#8221; (UHI), can be traced back to different factors, the most prominent being soil sealing, lower albedo and lack of effective ventilation.&lt;/p&gt;&lt;p&gt;City planners have started developing mitigation strategies to reduce future forecasted heat stress in urban regions. While some heat reduction strategies are currently intensely scrutinized and applied within pilot projects, the efficiency of latter mitigation actions can be overseen due to the low density of reference in situ air temperature measurements in urban environments. The same problem applies when trying to benchmark modeling studies of UHI as the amount of benchmarking data may be insufficient.&lt;/p&gt;&lt;p&gt;To overcome this lack of data, over the last two years, a dense air temperature measurement network has been installed in the Swiss cities of Basel and Zurich, counting more than 450 sensors. The low-cost air temperature sensors are installed on street lamps and traffic signs in different local climate zones of the city with an emphasis on street canyons, where air temperatures are expected to be the largest and most of the city&amp;#8217;s population lives and works. These low-cost sensors add valuable meteorological information in cities and complement the WMO reference stations.&lt;/p&gt;&lt;p&gt;Air temperature measurements from the low-cost sensor network were controlled for accuracy, reliability and robustness and homogenized in order to minimize radiation errors, although 40% of the stations were equipped with self-built radiation shields, allowing an efficient passive ventilation of the installed sensors.&lt;/p&gt;&lt;p&gt;We demonstrate the strength of our network by presenting first results of two exemplary heat waves that occurred in July 2019 and August 2020 and show that a) the radiation-error corrected datasets correlate well with different high-quality reference WMO stations, and b) the existence of urban heat islands in Zurich and Basel can be well confirmed, showing significant air temperature differences of several degrees between rural and urban areas.&lt;/p&gt;&lt;p&gt;The results demonstrate the advantages of a high-density low-cost air temperature network as a benchmark for future urban heat islands modelling studies.&lt;/p&gt;

Temperature Mapping of Localized Hot Spots on Microelectronic Chip Surfaces

1991 ◽  
Vol 113 (3) ◽  
pp. 286-293 ◽  
Author(s):  
S. Heng ◽  
W. Z. Black
Keyword(s):  
Image Processing ◽  
Digital Image Processing ◽  
Digital Image ◽  
Temperature Data ◽  
Temperature Measurements ◽  
Apparent Temperature ◽  
Surface Emissivity ◽  
Maximum Heat ◽  
Temperature Mapping ◽  
Infrared Measurements

This paper describes the use of digital image processing in conjunction with an infrared imaging apparatus to locate and quantify “micro” hot spot temperatures on the surface of energized microelectronic chips. Briefly, the temperature mapping/processing procedure creates emissivity maps for the surface of the chip at different isothermal conditions. The emissivity map images are digitized and stored as a 512 × 512 pixel array, of which 400 lines contain IR information. Apparent temperature measurements are then collected with the chip energized in its normal operating environment. These apparent temperature data are digitized and stored as a 512 × 512 integer array using the same format as the digitized emissivity data. Before correcting for emissivity variations, the apparent temperature images are rectified using digital image processing to precisely overlay the spatial coordinates of the emissivity map. Finally, actual temperature maps are obtained by correcting the apparent temperature data for the local emissivity variations and background reflections. The computer driven measurement technique has been applied to the task of measuring localized temperatures on areas as small as 30 μm on the surface of an energized chip to an accuracy of ±1°C once the surface emissivity is accurately known. The infrared equipment, image processing hardware and supporting software are used to measure the temperature distribution on the surface of a 4.7 mm × 4.7 mm energized chip. IR measured temperatures at isolated locations on the chip are compared with results obtained by the resistance-temperature technique. Since the resistance-temperature technique provides an area-averaged temperature for the energized region, the result obtained from the high resolution IR measurements yields higher localized temperatures. Results are presented for peak surface temperatures up to 100°C and maximum heat flux values of 7.9x106 W/m2. A separate set of infrared measurements are used to predict the influence of surface emissivity on the accuracy of the temperature measurements.

Tool-Work Thermocouple Temperature Measurements—Theory and Implementation Issues

1993 ◽  
Vol 115 (4) ◽  
pp. 432-437 ◽  
Author(s):  
D. A. Stephenson
Keyword(s):  
Measurement Errors ◽  
Cutting Tools ◽  
Electrical Potential ◽  
Temperature Measurements ◽  
Theoretical Understanding ◽  
Machining System ◽  
Thermocouple Method ◽  
The Difference ◽  
Thermocouple Temperature ◽  
Tools Wear

Since cutting tools wear by temperature-activated mechanisms, it would be desirable to make tool temperature measurements during machinability tests. However, none of the laboratory methods for measuring temperatures reported in the literature is simple and reliable enough for routine testing. The method which is most promising is the tool-work thermocouple method, which yields a repeatable result which correlates well with tool wear for many materials. This method is not normally used in machinability testing because it is not clear what temperature the method actually measures and because, as conventionally described, it cannot be used for roughing cuts at high cutting speeds. The purpose of this paper is to extend both the theoretical understanding and range of application of the tool-work thermocouple method. The question of what temperature is measured by the method is answered by analyzing the electrical potential distribution in a cutting tool due to a distributed interfacial emf. It is shown that in general the tool-work thermocouple temperature differs from the average interfacial temperature, but that for tungsten carbide tools the difference is usually small. The isolation of the tool-work thermocouple circuit is also considered. Methods of measuring signals without introducing insulation between the chuck and workpiece and reducing the machining system stiffness are described. Finally, methods of minimizing measurement errors due to secondary junctions are discussed. Sample signals from machinability tests on steels are used to illustrate significant points.

scholarly journals Satellite-Based Personal UV Dose Estimation

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 268
Author(s):  
Todd C. Harris ◽  
Laurent Vuilleumier ◽  
Claudine Backes ◽  
Athanasios Nenes ◽  
David Vernez
Keyword(s):  
Measurement Errors ◽  
Low Cost ◽  
Public Health Research ◽  
Mobile App ◽  
Population Exposure ◽  
Dose Estimation ◽  
Annual Dose ◽  
Significant Step ◽  
Uv Dose ◽  
Dosimetry Measurement

Epidemiology and public health research relating to solar ultraviolet (UV) exposure usually relies on dosimetry to measure UV doses received by individuals. However, measurement errors affect each dosimetry measurement by unknown amounts, complicating the analysis of such measurements and their relationship to the underlying population exposure and the associated health outcomes. This paper presents a new approach to estimate UV doses without the use of dosimeters. By combining new satellite-derived UV data to account for environmental factors and simulation-based exposure ratio (ER) modelling to account for individual factors, we are able to estimate doses for specific exposure periods. This is a significant step forward for alternative dosimetry techniques which have previously been limited to annual dose estimation. We compare our dose estimates with dosimeter measurements from skiers and builders in Switzerland. The dosimetry measurements are expected to be slightly below the true doses due to a variety of dosimeter-related measurement errors, mostly explaining why our estimates are greater than or equal to the corresponding dosimetry measurements. Our approach holds much promise as a low-cost way to either complement or substitute traditional dosimetry. It can be applied in a research context, but is also fundamentally well-suited to be used as the basis for a dose-estimating mobile app that does not require an external device.

scholarly journals THE VALUE OF ROBUST STATISTICAL FORECASTS IN THE COVID-19 PANDEMIC

2021 ◽  
Vol 256 ◽  
pp. 19-43
Author(s):  
Jennifer L. Castle ◽  
Jurgen A. Doornik ◽  
David F. Hendry
Keyword(s):  
Structural Change ◽  
Measurement Errors ◽  
Epidemiological Models ◽  
Short Term ◽  
Data Measurement ◽  
Policy Interventions ◽  
Changing Trends ◽  
Technological Advances ◽  
The Difference ◽  
The Uk

The Covid-19 pandemic has put forecasting under the spotlight, pitting epidemiological models against extrapolative time-series devices. We have been producing real-time short-term forecasts of confirmed cases and deaths using robust statistical models since 20 March 2020. The forecasts are adaptive to abrupt structural change, a major feature of the pandemic data due to data measurement errors, definitional and testing changes, policy interventions, technological advances and rapidly changing trends. The pandemic has also led to abrupt structural change in macroeconomic outcomes. Using the same methods, we forecast aggregate UK unemployment over the pandemic. The forecasts rapidly adapt to the employment policies implemented when the UK entered the first lockdown. The difference between our statistical and theory based forecasts provides a measure of the effect of furlough policies on stabilising unemployment, establishing useful scenarios had furlough policies not been implemented.

scholarly journals Molecularly imprinted electrospun fiber membrane for colorimetric detection of hexanoic acid

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 500-510
Author(s):  
Xiaoguang Ying ◽  
Jieyuan He ◽  
Xiao Li
Keyword(s):  
Low Cost ◽  
Electrospun Fiber ◽  
Colorimetric Detection ◽  
Hexanoic Acid ◽  
Bromocresol Purple ◽  
Fiber Membrane ◽  
Color Changes ◽  
Before And After ◽  
The Difference ◽  
Imagej Software

Abstract An imprinted electrospun fiber membrane was developed for the detection of volatile organic acids, which are key components of human body odor. In this study, hexanoic acid (HA) was selected as the target, polymethyl methacrylate (PMMA) was used as the substrate, and colorimetric detection of HA was achieved by a bromocresol purple (BCP) chromogenic agent. The results showed that the morphology of the fiber membrane was uniform and continuous, and it showed excellent selectivity and specificity to HA. Photographs of the color changes before and after fiber membrane adsorption were recorded by a camera and quantified by ImageJ software by the difference in gray value (ΔGray). This method is simple, intuitive, and low cost and has great potential for application in human odor analysis.

Sign in / Sign up

Export Citation Format

Share Document