Artículos de revistas: "Calibration chamber test"

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Been, K., B. E. Lingnau, J. H. A. Crooks y B. Leach. "Cone penetration test calibration for Erksak (Beaufort Sea) sand". Canadian Geotechnical Journal 24, n.º 4 (1 de noviembre de 1987): 601–10. http://dx.doi.org/10.1139/t87-074.

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Interpretation of the cone penetration test in sands is generally based on empirical calibrations from tests in large-diameter calibration chambers. Although interpretation of these calibration data for clean sands in terms of the state parameter is expected to be broadly applicable to other sands, material-specific correlations are desirable for many projects. This paper describes a series of calibration chamber tests carried out on a sand dredged from the Beaufort Sea for construction of artificial islands. This Erksak sand is a uniformly graded, subrounded medium-grained sand with a fines content of 3–6%. The testing chamber described is 1.4 m in diameter, and allows independent control of vertical, horizontal, and back pressures on the sand sample. Samples of the sand were prepared by moist compaction to preserve the fines content, and then back pressure saturated.The chamber test data are presented and confirm that the Erksak sand fits the general trends observed for other sands very well. A method is also described that allows the interpretation to be consistent, even in the event that nonuniform void ratios occur in the samples. Measurements of horizontal stress behind the cone tip, which is a new development in cone penetrometer testing, are also presented. Key words: cone penetrometer, sands, in situ tests, state, calibration chamber, horizontal stress measurement.

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2

Hazen, John y L. Scorsone. "Infrared Sensor Calibration Facility". Journal of the IEST 35, n.º 1 (1 de enero de 1992): 33–40. http://dx.doi.org/10.17764/jiet.2.35.1.d536816582691754.

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The Boeing Infrared Sensor (BIRS) Calibration Facility represents a major capital investment by The Boeing Company in optical and infrared technology. The facility was designed and built for calibrating and testing new generation large aperture long wave infrared (LWIR) sensors, seekers, and related technologies. The capability exists to perform both radiometric and goniometric calibrations of large infrared sensors under simulated environmental operating conditions. The system is presently configured for endoatmospheric calibrations with a uniform background field that can be set to simulate the expected mission background levels. During calibration, the sensor under test is also exposed to expected mission temperatures and pressures within the test chamber. The facility could be converted for exoatmospheric testing. The first major test runs in the facility were completed during 1989 with very satisfactory results. This paper will describe system configuration and hardware elements, and will address the modifications made to date. Pitt-Des Moines. Inc. (PDM) of Pittsburgh, Pennsylvania, was the contractor for the turnkey design and construction of the test chambers and thermal vacuum systems. Hughes Danbury Optical Systems (formerly Perkin Elmer Optical Systems) was the hardware supplier for the optical hardware. The Boeing Company performed all optical assembly, integration, testing, and alignment on-site.

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3

Goh, Anthony T. C. "Neural Networks for Evaluating CPT Calibration Chamber Test Data". Computer-Aided Civil and Infrastructure Engineering 10, n.º 2 (marzo de 1995): 147–51. http://dx.doi.org/10.1111/j.1467-8667.1995.tb00277.x.

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4

Kurup, P. U., G. Z. Voyiadjis y M. T. Tumay. "Calibration Chamber Studies of Piezocone Test in Cohesive Soils". Journal of Geotechnical Engineering 120, n.º 1 (enero de 1994): 81–107. http://dx.doi.org/10.1061/(asce)0733-9410(1994)120:1(81).

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5

Teh, Cee-Ing. "Calibration Chamber Studies of Piezocone Test in Cohesive Soils". Journal of Geotechnical Engineering 121, n.º 5 (mayo de 1995): 454–56. http://dx.doi.org/10.1061/(asce)0733-9410(1995)121:5(454).

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6

Shweikani, R. y G. Raja. "Design, construct and test of a calibration radon chamber". Radiation Measurements 40, n.º 2-6 (noviembre de 2005): 316–19. http://dx.doi.org/10.1016/j.radmeas.2005.05.010.

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7

Shang, Jinkui, Ronghuan Zhao, Zhaonan Xu y Hongjie Zhong. "Research on global calibration technology of pressure sensitive paint based on airtight chamber". Journal of Physics: Conference Series 2364, n.º 1 (1 de noviembre de 2022): 012022. http://dx.doi.org/10.1088/1742-6596/2364/1/012022.

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Abstract Pressure sensitive paint (PSP) technology has been widely applied in wind-tunnel test. Generally, PSP calibration data are obtained using a calibration sample in laboratory priori calibration device, which the sample is sprayed at the same time with the test model.In this study, taking the real test model as the calibration object, a global calibration technology of PSP coating on the surface of the test model is proposed, which is verified in the airtight chamber, and the effective PSP calibration data are obtained. A two-component fast response PSP coating was used in the study. In the validation test, a flying wing model is used, the flying wing model sprayed with PSP coating was placed in the airtight chamber. 11 groups of calibration tests were carried out in the environment of 0.06 MPa ~ 0.14 MPa and 30°C ~50°C, and the calibration curves obtained showed good consistency.

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8

Gibbons, David. "Environmental Chamber Temperature Calibration: Which Method to Use?" Journal of the IEST 49, n.º 2 (1 de octubre de 2006): 8–15. http://dx.doi.org/10.17764/jiet.49.2.2603362qtt442142.

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Calibration of environmental simulation temperature test chambers is anything but simple. This article addresses factors that complicate attempts to calibrate these machines, and discusses strengths and weaknesses of various calibration approaches.

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9

Ridwan, M. y T. Taryo. "Implementation of Fuzzy Logic Controller for Pressure Sensor Calibration Chamber". International Journal of Automotive and Mechanical Engineering 18, n.º 2 (26 de julio de 2021): 8825–32. http://dx.doi.org/10.15282/ijame.18.2.2021.20.0676.

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Atmospheric pressure is a weather element that must be observed in the field of meteorology. Electronic barometers, aneroid barometers, mercury barometers are generally instruments for atmospheric pressure measurement. The barometer must be calibrated periodically to ensure the performance of the instrument. To achieve the best target uncertainty during calibration, besides using an accurate primary standard barometer, a stable pressure controller is also needed. Pressure calibration media using a pressurised test chamber is more beneficial due to its capability to accommodate all types of pressure sensors. However, pressurise test chamber still requires an operator to control and stabilise pressure inside the test chamber. In this study, fuzzy logic has been programmed into a microcontroller to control the solenoid valve and vacuum pump for regulating air pressure inside a pressurised test chamber automatically. Fuzzy logic changes the solenoid valve states periodically by varying the opening and closing times. The final result of this study is a comparison between the calibration results using pressure controller with fuzzy logic and without fuzzy logic with the same primary standard and unit under test. The result of expanded uncertainty without a fuzzy logic controller is 13.06 hectopascal. Meanwhile, the pressure calibration process using fuzzy logic to control pressure in pressurised test chamber achieve 0.09 hectopascal of expanded uncertainty in 1000 hectopascal pressure value with coverage factor, k=2, and confidence level of no less than 95 %.

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10

Straż, Grzegorz. "Preliminary investigations of organics soil in a new calibration chamber with the use of the FVT and DPL probe". E3S Web of Conferences 49 (2018): 00109. http://dx.doi.org/10.1051/e3sconf/20184900109.

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The proposal of investigations of soft organic soils in a new calibration chamber performed at the Rzeszow University of Technology has been presented in this paper. The unique feature of this chamber is the possibility of simultaneous soil testing with the use of two penetrometers: FVT (Field Vane Test) and DPL (Dynamic Probing Light). It has been possible due to the large size of the cylindrical soil sample: 62.5 cm in diameter and max. 80 cm high. Additionally, a construction with a new calibration chamber has been described, concerning potential capabilities and restrictions when conducting researches. The presented calibration chamber ensures the stability of the parameters set during the tests, which allows one to compare the test results and search for the relationship between the analyzed parameters. Shear strength from the FVT test was adopted as reference. The results of preliminary research were presented and a detailed research plan was prepared, which will be implemented in the next stages of the investigations.

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11

Bressler, M., N. Lamb, R. Neilson y S. Windle. "A direct test of Auger cascade induced nucleation from heavy element contamination in C₃F₈ bubble chambers". Journal of Instrumentation 17, n.º 03 (1 de marzo de 2022): P03004. http://dx.doi.org/10.1088/1748-0221/17/03/p03004.

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Abstract Understanding and quantifying the gamma-induced bubble nucleation background in clean nuclear recoil detection bubble chambers is of utmost importance to bubble chamber based dark matter searches. We present data confirming the hypothesis that large Auger cascades from high-Z elements such as iodine and xenon dramatically increase the response of C3F8 bubble chambers to gamma rays. These tests, performed with a small calibration bubble chamber filled with C3F8+𝒪(10) ppm xenon, show that the probability of bubble nucleation scales with the rate of xenon inner-shell vacancies, reaching values >10% per K-Shell vacancy for Seitz thresholds of interest to future dark matter searches in bubble chambers. We also place an upper limit on bubble nucleation probability for argon Auger events, relevant to large future bubble chambers which may contain some residual atmospheric argon after the active fluid fill.

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12

Drewry, Jessica L., J. Mark Powell y Christopher Y. Choi. "Design and Calibration of Chambers for the Measurement of Housed Dairy Cow Gaseous Emissions". Transactions of the ASABE 60, n.º 4 (2017): 1291–300. http://dx.doi.org/10.13031/trans.12046.

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Abstract. The increased global demand for milk and other dairy products over the past decade has heightened concerns about the potential for increased environmental impacts. Accurate measurement of gas emissions from dairy cows is essential to assess the effects of cow diets and other management practices on both the composition and rate of gas emissions. In this article, methodologies are described to instrument, calibrate, and assess the uncertainty of gas emissions by cows housed in chambers that simulate production settings. The supply and exhaust ducts of each chamber were equipped with pitot tubes, temperature and relative humidity probes, and gas samplers to monitor airflow rates, gas composition, and gas emission rates. A Fourier transform infrared spectroscopy (FTIR) instrument was used to quantify gaseous concentrations in the gas samples on a semi-continuous basis. The measurement uncertainty of the rate of gaseous emission from the chambers was quantified, and gas concentration and differential pressure, as measured by the pitot tubes, were identified as the primary parameters contributing to gas emission uncertainties. Mass recovery tests determined that the recovery of methane from each chamber was within 10% of the released mass. Fan operating curves were experimentally determined to identify optimum differential chamber pressures to minimize gas leakage from the chambers. A computational fluid dynamics model was developed to assess air mixing patterns and define steady-state conditions. The model was validated with experimental data of air velocity within each chamber. These procedures will facilitate accurate measurement of gas emissions from housed dairy cows and provide a laboratory to test various gas mitigation treatments. Keywords: Computational fluid dynamics, Dairy, Emission chamber.

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13

Chaney, RC, KR Demars, D. Penumadu y J.-L. Chameau. "Interpretation of Model Pressuremeter Test Using Automated Clay Calibration Chamber Data". Geotechnical Testing Journal 21, n.º 1 (1998): 18. http://dx.doi.org/10.1520/gtj10421j.

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14

de Izarra, G., B. Geslot, S. Bréaud, A. Pepino, J.-F. Villard y P. Filliatre. "Test Results of an Innovative and Modular Sensor Design for Fission Chamber Studies". EPJ Web of Conferences 225 (2020): 03006. http://dx.doi.org/10.1051/epjconf/202022503006.

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Since many years, the Instrumentation, Sensors and Dosimetry laboratory at CEA Cadarache has been working to propose innovative and robust design of fission chambers. In this framework, few simulation tools like Chester or PyFc were developed to make detector prototyping and optimisation possible. Up to now, the code experimental validations are scarce mainly because of the lack of flexibility of regular fission chambers. In order to set up an experimental database for code validation, an innovative modular twin fission chamber, the CFTM, was designed. It allows to set with precision the inter-electrode gap, the filling gas pressure as well as the fissile deposit used. This detector was irradiated in Minerve zero power reactor in order to gather results for code validation. Thanks to a calibration procedure, a bank of experimental results is available for simulation validation.

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15

Sadrekarimi, Abouzar y Stephen Jones. "Verification of Seismic Cone Penetration Test Calibration Chamber Tests on a Sand". Geotechnical Testing Journal 45, n.º 2 (9 de diciembre de 2021): 20210068. http://dx.doi.org/10.1520/gtj20210068.

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16

Klein, L. y A. D. G. Wright. "Construction and operation of open-circuit methane chambers for small ruminants". Australian Journal of Experimental Agriculture 46, n.º 10 (2006): 1257. http://dx.doi.org/10.1071/ea05340.

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A detailed description of the construction, calibration and operation of 4 open-circuit chambers designed to measure methane emissions from sheep is given. These chambers have accommodated sheep under ad libitum feeding and have been used in short-term experiments and over extended periods of time. A real-time base data acquisition and process control system provided 24 h operation of the methane chambers. The gas volume measurement system consisted of dry test meters and sensors for differential and absolute pressure, temperature and relative humidity. This enabled correction of methane chamber exhaust air volume to standard temperature and pressure. Temperatures and relative humidity during measurements ranged from 21.0 to 23.1°C and 53.8 to 78.9%, respectively. The gas chromatograms were calibrated 3 times a day using commercially available gas standards. Recovery tests were conducted on each chamber by bleeding a methane gas standard into the chamber at a rate similar to methane production by sheep, with 94.4–107.1% of the methane gas recovered. Measurements on 32 sheep gave methane emissions within predicted levels and identified several low methane-producing sheep.

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17

Reiffsteck, Philippe, Jean Benoît, Quan Huy Dang y Panagiotis Georgios Karagiannopoulos. "Simplified method for evaluation of liquefaction based on pressuremeter tests (PMT)". Revue Française de Géotechnique, n.º 173 (2022): 1. http://dx.doi.org/10.1051/geotech/2022014.

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Liquefaction is of major concern in many countries subjected to seismic hazard. In practice, prediction of liquefaction is performed using simplified methods based on in situ tests such as the standard penetration test (SPT) or the cone penetration test (CPT). For some applications such as large projects (tunnels, high rise buildings), the Ménard pressuremeter is preferred as it provides a well-established method for foundation design. However, no simplified method to evaluate liquefaction potential has been fully developed for the pressuremeter. Based on pressuremeter calibration chamber and field tests on sands, a chart is proposed for estimating the liquefaction susceptibility of saturated sands. In addition, a method to correct the measured limit pressure from pressuremeter tests is also proposed for tests in sands with fines content. The method was evaluated using extensive data obtained from tests performed in a calibration chamber using clean sand and sand with fines content against 45 pressuremeter tests performed in situ in various soil conditions. Based on these tests, a relationship was obtained between the field data and the chart developed from the calibration chamber tests. The paper also provides suggestions to correct the limit pressure to account for the fines content.

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18

Coveney, D. "Climatic Engineering". Journal of the IEST 33, n.º 1 (1 de enero de 1990): 70–79. http://dx.doi.org/10.17764/jiet.2.33.1.j76t20tj1525g10n.

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Facilities at Canada's National Research Council for research into the effects of climate on engineering equipment are described. The Low Temperature Laboratory currently operates a large climatic test chamber, two smaller cold chambers, a cold chest for extremely cold temperatures, an icing tunnel, a helicopter icing facility, and a heat pump calorimeter. The capabilities and limitations of the test chambers are illustrated through descriptions of a variety of tests. Growth of ice on objects and the development and calibration of icing detectors in the icing tunnel are described to illustrate the capabilities of the tunnel. A description is presented of the inflight evaluation of helicopter performance in a supercooled vapor cloud produced by the helicopter icing facility.

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19

Butlanska, Joanna, Marcos Arroyo, Antonio Gens y Catherine O’Sullivan. "Multi-scale analysis of cone penetration test (CPT) in a virtual calibration chamber". Canadian Geotechnical Journal 51, n.º 1 (enero de 2014): 51–66. http://dx.doi.org/10.1139/cgj-2012-0476.

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A virtual calibration chamber was developed using a three-dimensional (3D) discrete element method (DEM) to perform cone penetration tests (CPTs) on a discrete analogue of Ticino sand. The macroscale response of the DEM model was previously shown to be in good quantitative agreement with that of analogous physical models. In the current study the performance of the model at meso and microscale levels of resolution is examined. The microscale response is examined using particle displacements and contact force distributions. The mesoscale behaviour is examined using stress and strain fields obtained through appropriate averaging and interpolating procedures. Four CPTs are examined at the steady-state penetration stage. The effects of radial boundary conditions, initial stress state, initial average density, and particle rotational inertia are examined. The ability of the micro and mesoscale data to identify and explain the relevant mechanisms underlying the significant differences in the macroscale response of the models is discussed. Comparisons with similar phenomena observed in physical tests are also highlighted.

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20

Jarast, Pegah y Majid Ghayoomi. "Numerical Modeling of Cone Penetration Test in Unsaturated Sand inside a Calibration Chamber". International Journal of Geomechanics 18, n.º 2 (febrero de 2018): 04017148. http://dx.doi.org/10.1061/(asce)gm.1943-5622.0001052.

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21

McManus, M., F. Romano, G. Royle, D. Botnariuc, D. Shipley, H. Palmans y A. Subiel. "Determination of beam quality correction factors for the Roos plane-parallel ionisation chamber exposed to very high energy electron (VHEE) beams using Geant4". Physics in Medicine & Biology 67, n.º 6 (17 de marzo de 2022): 065011. http://dx.doi.org/10.1088/1361-6560/ac5a94.

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Abstract Detailed characterisation of the Roos secondary standard plane-parallel ionisation chamber has been conducted in a novel 200 MeV Very High Energy Electron (VHEE) beam with reference to the standard 12 MeV electron calibration beam used in our experimental work. Stopping-power-ratios and perturbation factors have been determined for both beams and used to calculated the beam quality correction factor using the Geant4 general purpose MC code. These factors have been calculated for a variety of charged particle transport parameters available in Geant4 which were found to pass the Fano cavity test. Stopping-power-ratios for the 12 MeV electron calibration beam quality were found to agree within uncertainties to that quoted by current dosimetry protocols. Perturbation factors were found to vary by up-to 4% for the calibration beam depending on the parameter configuration, compared with only 0.8% for the VHEE beam. Beam quality correction factors were found to describe an approximately 10% lower dose than would be originally calculated if a beam quality correction were not accounted for. Moreover, results presented here largely resolve unphysical chamber measurements, such as collection efficiencies greater than 100%, and assist in the accurate determination of absorbed dose and ion recombination in secondary standard ionisation chambers.

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22

Laksono, Arief y I. Gusti Agung Widagda. "Calibration of the BMP280 and ESP-12S Based Wireless Atmospheric Pressure Measure Equipment Using a Pressure Chamber". BULETIN FISIKA 23, n.º 1 (6 de marzo de 2021): 1. http://dx.doi.org/10.24843/bf.2022.v23.i01.p01.

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In order to study and practice the method of meteorological atmospheric pressure gauge calibration, the design, assembly and calibration of an experimental wireless atmospheric pressure gauge based on the BMP280 digital pressure sensor and the System on Chip ESP-12S has been carried out. Using the Vaisalla PTB330 digital barometer secondary pressure standard, the instrument is calibrated in the pressure chamber in the pressure range 850-1050 hPa with a maximum tolerance limit of ± 0.15 hPa at a 95% confidence level. Based on the test results of the correction parameters and U95, it shows that the reliability of the sensor interface system and the internal correction application method used in the calibration process provide calibration results that meet the requirements of the WMO standard. The precision test on repeatability conditions based on ISO5725: 1994 is also used as a measure of tool precision. Through this calibration report, the performance and accuracy of the BMP280 sensor in relation to measurements on meteorological objects, especially atmospheric pressure can be known and studied further.

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23

Alfs, D., A. Asaturyan, M. Carmignotto, M. Diermaier, W. Eyrich, B. Głowacz, D. Grzonka et al. "Drift chamber calibration and particle identification in the P-349 experiment". EPJ Web of Conferences 199 (2019): 05017. http://dx.doi.org/10.1051/epjconf/201919905017.

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The goal of the P-349 experiment is to test whether 3.5 GeV/c antiprotons produced in high-energy proton-proton collisions are polarized in view of the preparation of a polarized antiproton beam. In this article, we present the details of the ongoing analysis focused on the drift chambers calibration and particle identification with DIRC.

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24

Suemasa, Naoaki, Jiro Takemura, Akihiko Hirooka y Tsutomu Kimura. "A Study on Cone Penetration Resistance in Cohesive Soils by a Calibration Chamber Test." Doboku Gakkai Ronbunshu, n.º 493 (1994): 69–78. http://dx.doi.org/10.2208/jscej.1994.493_69.

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25

Kim, Jae-Hong y Eun-Sang Im. "Evaluation of Discharge Capacity for Gravel mat due to Geosynthetic Using Calibration Chamber Test". Journal of the Korean Geosynthetic Society 13, n.º 2 (30 de junio de 2014): 11–20. http://dx.doi.org/10.12814/jkgss.2014.13.2.011.

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26

Kusumawardani, Yanti, Endang Dian Setioningsih y Dyah Titisari. "Water Bath Calibration Device with Data Storage Using Six Thermocouple Sensor". Journal of Electronics, Electromedical Engineering, and Medical Informatics 2, n.º 2 (23 de julio de 2020): 40–47. http://dx.doi.org/10.35882/jeeemi.v2i2.2.

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Uneven distribution of temperature in the chamber water bath can cause the temperature conditions in the chamber are not the same. Temperature, humidity, atmospheric pressure, and dust particles are the main factors which adversely affect the accuracy of water bath’s temperature. Therefore, the purpose of this study is to design a calibration device for water bath with number of channel 6. In this study the system can detect temperatures at each chamber point. The K-type Thermocouple sensor is used to detect the temperature at each chamber point with the help of the MAX6675 module as a signal conditioning amplifier. The sensor readings will be displayed on a Personal Computer using a USB cable, the sensor readings can be stored on a Personal Computer in the form of a TXT so that data can be reprocessed using Microsoft Excel for further calibration purposes. This study aims to facilitate the calibration process and the processing of calibration data. The results of digital measurements obtained a temperature error value of 40 ° C channel 1 1,4 %, channel 2 1.8%, channel 3 0.4%, channel 4 0.2%, channel 5 0.2% and channel 6 0.2%.Temperature 50 ° C channel 1 2.25%, channel 22.26%, channel 3 2.00%, channel 4 2.44%, channel 5 2% and channel 6 1.6%. S.uhu 60 ° C channel 1 0.3%, channel 20.6%, channel 3 0.5%, channel 4 1.5%, channel 5 2% and channel 6 1.8%. Based on the test results, this module has the lowest error of 0.2% and the highest error of 2.44%. The results of this research can be implemented as a Water Bath calibration tool to maintain the temperature stability of the instrument

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27

Gobi, K., B. Kannapiran, D. Devaraj y K. Valarmathi. "Design, performance evaluation and analysis of the inlet tube of pressure sensor for chamber pressure measurement". Sensor Review 39, n.º 4 (15 de julio de 2019): 612–21. http://dx.doi.org/10.1108/sr-12-2017-0260.

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Purpose In Aerospace applications, the inlet tubes are used to mount strain gauge type pressure sensors on the engine under static test to measure engine chamber pressure. This paper aims to focus on the limitations of the inlet tube and its design aspects to serve better in the static test environment. The different sizes of the inlet tubes are designed to meet the static test and safety requirements. This paper presents the performance evaluation of the designed inlet tubes with calibration results and the selection criteria of the inlet tube to measure combustion chamber pressure with the specified accuracy during static testing of engines. Design/methodology/approach Two sensors, specifically, one cavity type pressure sensor with the inlet tube of range 0-6.89 MPa having natural frequency of the diaphragm 17 KHz and another flush diaphragm type pressure sensor of the same range having −3 dB frequency response, 5 KHz are mounted on the same pressure port of the engine under static test to study the shortcomings of the inlet tube. The limitations of the inlet tube have been analyzed to aid the tube design. The different sizes of inlet tubes are designed, fabricated and tested to study the effect of the inlet tube on the performance of the pressure sensor. The dynamic calibration is used for this purpose. The dynamic parameters of the sensor with the designed tubes are calculated and analyzed to meet the static test requirements. The diaphragm temperature test is conducted on the representative hardware of pressure sensor with and without inlet tube to analyze the effect of the inlet tube against the temperature error. The inlet tube design is validated through the static test to gain confidence on measurement. Findings The cavity type pressure sensor failed to capture the pressure peak, whereas the flush diaphragm type pressure sensor captured the pressure peak of the engine under a static test. From the static test data and dynamic calibration results, the bandwidth of cavity type sensor with tube is much lower than the required bandwidth (five times the bandwidth of the measurand), and hence, the cavity type sensor did not capture the pressure peak data. The dynamic calibration results of the pressure sensor with and without an inlet tube show that the reduction of the bandwidth of the pressure sensor is mainly due to the inlet tube. From the analysis of dynamic calibration results of the sensor with the designed inlet tubes of different sizes, it is shown that the bandwidth of the pressure sensor decreases as the tube length increases. The bandwidth of the pressure sensor with tube increases as the tube inner diameter increases. The tube with a larger diameter leads to a mounting problem. The inlet tube of dimensions 6 × 4 × 50 mm is selected as it helps to overcome the mounting problem with the required bandwidth. From the static test data acquired using the pressure sensor with the selected inlet tube, it is shown that the selected tube aids the sensor to measure the pressure peak accurately. The designed inlet tube limits the diaphragm temperature within the compensated temperature of the sensor for 5.2 s from the firing of the engine. Originality/value Most studies of pressure sensor focus on the design of a sensor to measure static and slow varying pressure, but not on the transient pressure measurement and the design of the inlet tube. This paper presents the limitations of the inlet tube against the bandwidth requirement and recommends dynamic calibration of the sensor to evaluate the bandwidth of the sensor with the inlet tube. In this paper, the design aspects of the inlet tube and its effect on the bandwidth of the pressure sensor and the temperature error of the measured pressure values are presented with experimental results. The calibration results of the inlet tubes with different configurations are analyzed to select the best geometry of the tube and the selected tube is validated in the static test environment.

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Schnaid, F. y G. T. Houlsby. "Measurement of the properties of sand in a calibration chamber by the cone pressuremeter test". Géotechnique 42, n.º 4 (diciembre de 1992): 587–601. http://dx.doi.org/10.1680/geot.1992.42.4.587.

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29

Puppala, Anand J., Yalcin B. Acar y Mehmet T. Tumay. "Low Strain Dynamic Shear Modulus of Cemented Sand from Cone Penetration Test Results". Transportation Research Record: Journal of the Transportation Research Board 1548, n.º 1 (enero de 1996): 60–66. http://dx.doi.org/10.1177/0361198196154800109.

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Low strain dynamic shear modulus property is generally used to subclassify soil strata, determine elastic settlements under geotechnical structures, and characterize the dynamic nature of soils. Several methods to interpret the dynamic shear modulus of sands from in situ friction cone test results have been developed. These methods used calibration chamber test data of clean sands. Therefore, these methods are not valid for interpreting the shear modulus of cemented sands. Introduced here is an interpretation method to estimate the shear modulus of cemented sand. Thirty-seven friction cone penetration tests (CPTs) were conducted on artificially cemented sand specimens of relative densities ranging from 45 percent to 85 percent and confining pressures ranging from 100 to 300 kPa in a laboratory stress-strain-controlled calibration chamber. Cementation levels of 1 and 2 percent were used in preparing cemented specimens. Resonant column tests were also conducted on the same sand with identical cementation levels. The CPT and resonant column test data are used in developing an interpretation method that includes semiempirical correlations. Simple interpretation charts are also provided to directly estimate the low strain shear modulus of cemented sand from tip resistance, unconfined compressive strength, and relative density data. Comparisons between predictions of the proposed interpretation method and the present measured shear modulus test data indicate that the interpretation charts have provided reasonable predictions. The comparisons also indicate that the predicted results on clean sands obtained by different researchers are in agreement with each other.

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Sundermeier, Maximilian F. y Dirk Fischer. "Compact Radar Cross-Section Measurement Setup and Performance Evaluation". Advances in Radio Science 19 (17 de diciembre de 2021): 147–52. http://dx.doi.org/10.5194/ars-19-147-2021.

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Abstract. Radar cross-section measurements require the background reflections to be much lower than the reflections of the device under test. Although, anechoic chambers with special target holders meet this requirement, they are expensive and still have imperfections. To further reduce background reflections or to measure in environments where an anechoic chamber is not suitable, digital signal processing can be used to reduce background reflections. In this paper, a complete signal processing chain realized in Matlab is proposed, involving time gating of the measured target response and a background subtraction technique. Furthermore, the proposed signal processing includes a calibration procedure with either a single known calibration target or multiple known targets to improve measurement uncertainties. A compact measurement setup, consisting of a vector network analyzer and two horn antennas, is used to evaluate the overall performance and the advantages of a multiple known target calibration in a practical manner. The calibrated setup is able to measure the radar cross-section in a frequency range from 2 to 12 GHz with a mean error of less than 0.2 dB for both, VV and HH polarization combinations. It could also be shown, that a multi target calibration can result in an improvement of the measurement uncertainty by about 2.5 %.

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Pedro, António, Teresa Morgado y Helena Navas. "An Uncertainties Simulation Model Applied to an Automated Laminar Flowmeter". Applied Sciences 10, n.º 3 (29 de enero de 2020): 888. http://dx.doi.org/10.3390/app10030888.

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Aircraft oxygen regulators are a normally used specialized test bench designed to perform tests to the regulators during its work conditions. The tests are performed placing the regulator in the barometric chamber, where low pressure conditions are forced to simulate altitude conditions and then a flow is forced on the output of the regulator to simulate the inhalation of the user. The relevant test flows are measured by laminar flowmeters. These flowmeters are meant to measure the flowrate at pressures correspondent to altitudes between sea level altitude and fifty thousand feet. In this work a way was studied to automate laminar flowmeters used on oxygen regulator test benches. For this purpose, was developed a data acquisition system (DAS) using a microcontroller board and two microelectromechanical systems—MEMSs (a pressure and temperature sensor and a differential pressure sensor). Since these MEMSs did not have factory calibration, they were calibrated in this study. The automated flowmeter was also calibrated. To estimate the error of flow rate measured by this solution, an uncertainties simulation model based on the Monte Carlo method and several calibrations were performed. According to the automated flowmeter calibration, the uncertainty obtained (±0.45% fs) is accepted, but the authors only recommend its use for actual volumetric flowrate measurements.

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32

Snider, Jefferson R., Markus D. Petters, Perry Wechsler y Peter S. K. Liu. "Supersaturation in the Wyoming CCN Instrument". Journal of Atmospheric and Oceanic Technology 23, n.º 10 (1 de octubre de 2006): 1323–39. http://dx.doi.org/10.1175/jtech1916.1.

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Abstract Two thermal diffusion cloud condensation nuclei (CCN) instruments were intercompared using a nearly monodisperse test aerosol composed of sodium chloride and ammonium sulfate. The main objective of this work is the determination of the maximum steady-state supersaturation within a thermal diffusion chamber. This required analysis of the uncertainties associated with the calibration of the instrument’s plate temperature and light scattering measurement systems. The fraction of test particles activating to form cloud droplets, the activated fraction, was evaluated over a range of dry particle diameters at four supersaturations. Values of both the particle size, corresponding to an activated fraction equal to 0.5, and the width of a fitted activation function were derived. The former was used to evaluate the maximum steady-state chamber supersaturation. These studies reveal three significant findings. First, the derived chamber supersaturation is ∼40% smaller than values based on temperature measured at the top and bottom of the diffusion chamber. Second, using deliquesced test particles, mobility selected at a prescribed relative humidity, it is shown that the 40% discrepancy is not the result of a test particle shape effect. Third, the width of the activation function is substantially larger than the width of the test particle size spectra. Plausible explanations for the 40% bias are considered. Contributors are the unintentional overestimation of the temperature difference imposed across the CCN chamber and the implicit assumption that water at the top and bottom of the CCN chamber has a vapor pressure equal to that over pure water.

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Sapuan, Syarfa' Zahirah, Mohd Zarar Mohd Jenu y Alireza Kazemipour. "Issue on Calibration of Direct Feed Biconical Antenna in a Semi-Anechoic Chamber Using Standard Antenna Method". Advanced Materials Research 903 (febrero de 2014): 273–78. http://dx.doi.org/10.4028/www.scientific.net/amr.903.273.

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Antenna calibration is crucial to ensure the accuracy of Electromagnetic Compatibility (EMC) measurement results. Standard Antenna Method (SAM) is one of the methods widely used in antenna calibration which requires reference antenna with known Antenna Factor (AF) in a free space environment. The work presented in this paper is on the calibration of the AF of a direct-feed biconical antenna in a semi-anechoic chamber (SAC) with considerations given to the effects of ground plane, antenna height, reference antenna type and effects of phase center. The frequency range for the analysis is from 200 MHz to 2 GHz. It is found that antenna located 1.5 m from ground provides the best result compared to modeling. In addition, the phase centers of the reference and test antenna must be at the same positions during the measurements.

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Benammar, Mohieddine A., Sabbir H. M. Ahmad, Abderrazak Abdaoui, Hasan Tariq, Farid Touati, Mohammed Al-Hitmi y Damiano Crescini. "A Smart Rig for Calibration of Gas Sensor Nodes". Sensors 20, n.º 8 (20 de abril de 2020): 2341. http://dx.doi.org/10.3390/s20082341.

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Electrochemical gas sensors require regular maintenance to check and secure proper functioning. Standard procedures usually involve testing and recalibration of the sensors, for which working environments are needed. Periodic calibration is therefore necessary to ensure reliable and accurate measurements. This paper proposes a dedicated smart calibration rig with a set of novel features enabling simultaneous calibration of multiple sensors. The proposed calibration rig system comprises a gas mixing system, temperature control system, a test chamber, and a process-control PC that controls all calibration phases. The calibration process is automated by a LabVIEW-based platform that controls the calibration environment for the sensor nodes, logs sensor data, and best fit equation based on interpolation for every sensor on the node and uploads it to the sensor node for next deployments. The communication between the PC and the sensor nodes is performed using the same IEEE 802.15.4 (ZigBee) protocol that the nodes also use in field deployment for air quality measurement. The results presented demonstrate the effectiveness of the sensors calibration rig.

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35

Schnaid, F. y G. T. Houlsby. "Discussion: Measurement of the properties of sand in a calibration chamber by the cone pressuremeter test". Géotechnique 44, n.º 3 (septiembre de 1994): 529–32. http://dx.doi.org/10.1680/geot.1994.44.3.529.

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36

Khaled, K. M. y G. M. Mahmoud. "An investigation on the effect of humidity on the zero signal of a strain gauge measuring system". Universitas Scientiarum 23, n.º 1 (11 de mayo de 2018): 129. http://dx.doi.org/10.11144/javeriana.sc23-1.aint.

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Humidity is one of the most important ambient factors influencing torque calibration readings. The present study addresses the effect of relative humidity on the readings of reference torque transduction and amplification devices. The results revealed a linear effect of increasing humidity on the readings of a DMP40 torque amplifier and a torque transducer at four different temperatures. Furthermore, humidity effects were smaller on the DMP40 amplifier than on the torque transducer across all four temperatures. The results also showed that the summed effects of humidity on amplifier and transducer calibration readings were larger when each device was operated under different humidity and temperature conditions (i.e. torque amplifier placed inside a controlled climate chamber and transducer outside, and vice-versa); as opposed to smaller summed effects, observed when both devices were operated under the same ambient conditions (i.e. both inside the chamber). Therefore, it is recommended to test the effect of humidity in setups where the two devices are under common humidity conditions. This is likely to lower the uncertainty parameter of obtained torque calibration readings and is a useful consideration for inter-laboratory comparisons and performance testing.

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37

Del Rey, R., J. Alba, L. Bertó y A. Gregori. "Small-sized reverberation chamber for the measurement of sound absorption". Materiales de Construcción 67, n.º 328 (21 de septiembre de 2017): 139. http://dx.doi.org/10.3989/mc.2017.07316.

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This paper presents the design, construction, calibration and automation of a reverberation chamber for small samples. A balance has been sought between reducing sample size, to reduce the manufacturing costs of materials, and finding the appropriate volume of the chamber, to obtain reliable values at high and mid frequencies. The small-sized reverberation chamber, that was built, has a volume of 1.12 m3 and allows for the testing of samples of 0.3 m2. By using diffusers, to improve the diffusion degree, and automating measurements, we were able to improve the reliability of the results, thus reducing test errors. Several comparison studies of the measurements of the small-sized reverberation chamber and the standardised reverberation chamber are shown, and a good degree of adjustment can be seen between them, within the range of valid frequencies. This paper presents a small laboratory for comparing samples and making decisions before the manufacturing of larger sizes.

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Bilka, Tadeáၡ, Kirill Chilikin, David Dossett, Yinghui Guan, Jakub Kandra, Claus Kleinwort y Martin Sevior. "Alignment and Calibration of the Belle II Detector". EPJ Web of Conferences 214 (2019): 01040. http://dx.doi.org/10.1051/epjconf/201921401040.

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In spring 2018 the SuperKEKB electron-positron collider at High Energy Accelerator Research Organization (KEK, Tsukuba, Japan) will deliver its first collisions to the Belle II experiment. The aim of Belle II is to collect a data sample 50 times larger than the previous generation of BFactories taking advantage of the unprecedented SuperKEKB design luminosity of 8×1035cm-2s-1. The Belle II detector will allow to conduct precise measurements in the harsh collider environment, probing for signs of physics beyond the standard model at the precision frontier. In order to deliver data suitable for physics analysis, the detector has to be properly calibrated on a regular basis. Among other calibrations the detector alignment plays a key role. For example, precise measurements of time dependent CP-violation rely on the accurate alignment of the new vertex detector, as well as on the determination of the beamspot position and size. To automate the calibration procedures and manage the large amount of data and processing power needed for detector calibration, a software framework has been developed which allows to define the complete workflow and to execute it on a computing cluster. The framework integrates the Millepede II algorithm to solve the large minimization problem emerging in the track-based alignment and calibration of the pixel and strip detector, the central drift chamber, and the muon system. The first collision data will allow to test and to further improve and tune the alignment and calibration procedures. Although the vertexing capabilities will be limited due to the installation of only a small slice of the full vertex detector, the commissioning phase will allow to test most of the alignment procedure features and to prepare for the full operation. We will present the results achieved during the first data taking, the experience gained and the plans for the first physics run with the full detector.

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39

Curcoll, Roger, Josep-Anton Morguí, Armand Kamnang, Lídia Cañas, Arturo Vargas y Claudia Grossi. "Metrology for low-cost CO2 sensors applications: the case of a steady-state through-flow (SS-TF) chamber for CO2 fluxes observations". Atmospheric Measurement Techniques 15, n.º 9 (9 de mayo de 2022): 2807–18. http://dx.doi.org/10.5194/amt-15-2807-2022.

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Abstract. Soil CO2 emissions are one of the largest contributions to the global carbon cycle, and a full understanding of processes generating them and how climate change may modify them is needed and still uncertain. Thus, a dense spatial and temporal network of CO2 flux measurements from soil could help reduce uncertainty in the global carbon budgets. In the present study, the design, assembly, and calibration of low-cost air enquirer kits, including CO2 and environmental parameters sensors, is presented. Different types of calibrations for the CO2 sensors and their associated errors are calculated. In addition, for the first time, this type of sensor has been applied to design, develop, and test a new steady-state through-flow (SS-TF) chamber for simultaneous measurements of CO2 fluxes in soil and CO2 concentrations in air. The sensors' responses were corrected for temperature, relative humidity, and pressure conditions in order to reduce the uncertainty in the measured CO2 values and of the following calculated CO2 fluxes based on SS-TF. CO2 soil fluxes measured by the proposed SS-TF and by a standard closed non-steady-state non-through-flow (NSS-NTF) chamber were briefly compared to ensure the reliability of the results. The use of a multiparametric fitting reduced the total uncertainty of the CO2 concentration measurements by 62 %, compared with the uncertainty that occurred when a simple CO2 calibration was applied, and by 90 %, when compared to the uncertainty declared by the manufacturer. The new SS-TF system allows the continuous measurement of CO2 fluxes and CO2 ambient air with low cost (EUR ∼1200), low energy demand (<5 W), and low maintenance (twice per year due to sensor calibration requirements).

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40

Silvestre Patallo, Ileana, Rebecca Carter, David Maughan, Andrew Nisbet, Giuseppe Schettino y Anna Subiel. "Evaluation of a micro ionization chamber for dosimetric measurements in image-guided preclinical irradiation platforms". Physics in Medicine & Biology 66, n.º 24 (10 de diciembre de 2021): 245012. http://dx.doi.org/10.1088/1361-6560/ac3b35.

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Abstract Image-guided small animal irradiation platforms deliver small radiation fields in the medium energy x-ray range. Commissioning of such platforms, followed by dosimetric verification of treatment planning, are mostly performed with radiochromic film. There is a need for independent measurement methods, traceable to primary standards, with the added advantage of immediacy in obtaining results. This investigation characterizes a small volume ionization chamber in medium energy x-rays for reference dosimetry in preclinical irradiation research platforms. The detector was exposed to a set of reference x-ray beams (0.5–4 mm Cu HVL). Leakage, reproducibility, linearity, response to detector’s orientation, dose rate, and energy dependence were determined for a 3D PinPoint ionization chamber (PTW 31022). Polarity and ion recombination were also studied. Absorbed doses at 2 cm depth were compared, derived either by applying the experimentally determined cross-calibration coefficient at a typical small animal radiation platform ‘user’s’ quality (0.84 mm Cu HVL) or by interpolation from air kerma calibration coefficients in a set of reference beam qualities. In the range of reference x-ray beams, correction for ion recombination was less than 0.1%. The largest polarity correction was 1.4% (for 4 mm Cu HVL). Calibration and correction factors were experimentally determined. Measurements of absorbed dose with the PTW 31022, in conditions different from reference were successfully compared to measurements with a secondary standard ionization chamber. The implementation of an End-to-End test for delivery of image-targeted small field plans resulted in differences smaller than 3% between measured and treatment planning calculated doses. The investigation of the properties and response of a PTW 31022 small volume ionization chamber in medium energy x-rays and small fields can contribute to improve measurement uncertainties evaluation for reference and relative dosimetry of small fields delivered by preclinical irradiators while maintaining the traceability chain to primary standards.

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Hu, Zhuoyue, Min Zhu, Qiyao Wang, Xiaofeng Su y Fansheng Chen. "SDGSAT-1 TIS Prelaunch Radiometric Calibration and Performance". Remote Sensing 14, n.º 18 (11 de septiembre de 2022): 4543. http://dx.doi.org/10.3390/rs14184543.

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SDGSAT-1 was launched in November 2021, and TIS (Thermal infrared sensor) is a major instrument onboard this satellite. An analysis of the radiometric calibration and noise performance of the TIS has been carried out in the thermal vacuum chamber before launch in order to ensure that it meets the requirements. The prelaunch test results show NEdT (noise equivalent temperature difference) is 0.034 K, 0.047 K and 0.076 K@300 K for the three bands, respectively. The maximum fitting residuals are less than 0.5 K at measured blackbody temperatures. In addition, this paper also discusses the dependence between TIS performance and instrument temperature and focal plane array (FPA) temperature. The good radiometric and noise performance of TIS demonstrates it has potential to provide high resolution thermal remote sensing data in urban heat island, and other environmental issues research.

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42

Igarashi, Yu, Takahiro Nozaki, Hiroyuki Mizuno, Tomohiro Kuroki, Yuki Uchida, Miroslaw Janik y Takeshi Iimoto. "PRELIMINARY TECHNICAL DISCUSSION ON A NEW RADON AND ITS PROGENY CONTINUOUS MONITOR USING TWO-FILTER METHOD". Radiation Protection Dosimetry 184, n.º 3-4 (30 de abril de 2019): 418–21. http://dx.doi.org/10.1093/rpd/ncz072.

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Abstract Focusing on the scalability of Two-Filter Method, we started to develop a monitor for the concentration of radon and its progeny. In this study, we investigated the influence of a high-humidity environment on measuring radon concentration, and the influence of the decay chamber of the monitor on the measurement. In the high-humidity test, the conversion factor of (Bqm−3)/(cpm) tends to raise with increasing humidity. On the measurement of radon progeny, existence of the decay chamber of the monitor makes measurement sensitivity lower under environments of little aerosols. Radon concentration measurement by the developed monitor could be influenced by environmental humidity, and that counting loss could occur due to deposition of radon progeny inside of the decay chamber. Correction relating these would be needed based on the data of calibration tests.

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43

Mescia, L., O. Losito, V. Castrovilla, P. Bia y F. Prudenzano. "Antenna Calibration Methods for Antenna Factor Measurements". International Journal of Measurement Technologies and Instrumentation Engineering 2, n.º 4 (octubre de 2012): 43–59. http://dx.doi.org/10.4018/ijmtie.2012100104.

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In the fields of electromagnetic interference and electromagnetic compatibility, it is important to measure the strength of the electric field originating from electric devices. For this purpose, knowledge of the antenna factor of a receiving antenna is necessary. According to international standards, the accurate measurement of the antenna factor involves the use of calibration test sites characterized by very large sizes of both the ground plane and the empty space volume above it. As a consequence, these setup conditions make the antenna factor measurements quite expensive for the customer. In this paper, the authors discuss the well know antenna-based and site-based methods as well as recently measurement method called Antenna Impedance Method as able to obtain the free-space antenna factor. Moreover, the authors investigate on the suitability of semi-anechoic chamber for reliable antenna factor calibrations. In particular, the experimental measurements of the antenna factor obtained by using the antenna impedance method were compared with Standard Field Method and the data provided by the manufacturer of three antennas (Biconical, Log-periodic and Horn antenna) founding an agreement with the international standard ANSI C63.5-2006.

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Sciocchetti, G., G. Cotellessa, P. De Felice, P. G. Baldassini, M. Bovi, S. Tosti y E. Soldano. "The ENEA Facilities for Assessing the Quality of Indoor Radon Measurements". Radiation Protection Dosimetry 56, n.º 1-4 (1 de diciembre de 1994): 303–7. http://dx.doi.org/10.1093/oxfordjournals.rpd.a082476.

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Abstract A status report is given of the ENEA research activities on calibration and standardisation of radon measurement techniques. A description of radon standards and experimental facilities (the ENEA Radon Chamber and the 222Rn standard generator) developed at the Casaccia Research Centre is given. The experimental procedures to test the charcoal canister radon adsorption are described. The results of investigation of the response of passive plastic detectors (CR-39) at different exposure conditions at the ENEA radon chamber are discussed: dynamic range and accuracy of passive alpha track detectors in the range from 60 to about 7000 kBq.m-3.h radon exposure. Finally a brief description is given of the experimental facility that is under development to test instruments and methods that are used to measure the emanation/exhalation of radon gas from soils and building materials.

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45

Salgado, Rodrigo y Monica Prezzi. "Penetration Rate Effects on Cone Resistance: Insights From Calibration Chamber and Field Testing". Soils and Rocks 37, n.º 3 (1 de septiembre de 2014): 233–42. http://dx.doi.org/10.28927/sr.373233.

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Cone penetration in mixed or intermediate soils (soils containing mixtures of sand, silt and clay) is neither fully drained nor fully undrained at the standard cone penetration rate of 20 mm/s. Considerable research, mainly relying on centrifuge tests, has been undertaken to quantify the effects of penetration rate (and thus partial drainage) on cone resistance. In this paper, the effects of penetration rate on cone resistance in saturated clayey soils were investigated by performing field tests and miniature cone penetration tests in a calibration chamber. The field tests were performed at sites especially selected to span the range of drainage conditions from fully drained to fully undrained. The calibration chamber tests, using both conical and flat-tip penetrometers, were performed at different penetration rates in two specimens prepared by mixing kaolin clay and sand with different mixing ratios and one-dimensionally consolidateding the mixtures. A correlation between cone resistance and drainage conditions is established based on the cone penetration test results. The transitions from no drainage to partial drainage and from partial drainage to full drainage are defined as a function of penetration rate normalized with respect to the penetrometer diameter and the coefficient of consolidation.

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46

Silvestri, Vincenzo, Ghassan Abou-Samra y Christian Bravo-Jonard. "Effect of flow rules and elastic strains on pressuremeter test results in dense sand". Canadian Geotechnical Journal 46, n.º 2 (febrero de 2009): 160–67. http://dx.doi.org/10.1139/t08-108.

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Simple numerical methods that allow to obtain stress and strain paths in sand during self-boring pressuremeter tests are presented in this paper. The material is considered to undergo deformation in drained and plane-strain conditions. The flow rules of Rowe, Cambridge-type (Cam clay and Nova) model, and the sawtooth model are used in the analysis. Elastic strains are also considered in relation with the flow rule of Rowe. The proposed approach has been evaluated using a reference pressuremeter test performed on Ticino sand in a calibration chamber. The results indicate that the stress–strain–volume change responses of the sand predicted by the various models are quite similar, with and without consideration of the elastic strain components.

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McGinley, M. A. y C. M. McGinley. "Comparison of field olfactometers in a controlled chamber using hydrogen sulfide as the test odorant". Water Science and Technology 50, n.º 4 (1 de agosto de 2004): 75–82. http://dx.doi.org/10.2166/wst.2004.0225.

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A standard method for measuring and quantifying odour in the ambient air utilizes a portable odour detecting and measuring device known as a field olfactometer (US Public Health Service Project Grant A-58-541). The field olfactometer dynamically dilutes the ambient air with carbon-filtered air in distinct ratios known as “Dilutions-to-Threshold” dilution factors (D/Ts), i.e. 2, 4, 7, 15, etc. Thirteen US states and several cities in North America currently utilize field olfactometry as a key component of determining compliance to odour regulations and ordinances. A controlled environmental chamber was utilized, with hydrogen sulfide as the known test odorant. A hydrogen sulfide environment was created in this controlled chamber using an Advanced Calibration Designs, Inc. Cal2000 Hydrogen Sulfide Generator. The hydrogen sulfide concentration inside the chamber was monitored using an Arizona Instruments, Inc. Jerome Model 631 H2S Analyzer. When the environmental chamber reached a desired test concentration, test operators entered the chamber. The dilution-to-threshold odour concentration was measured using a Nasal Ranger Field Olfactometer (St Croix Sensory, Inc.) and a Barnebey Sutcliffe Corp. Scentometer. The actual hydrogen sulfide concentration was also measured at the location in the room where the operators were standing while using the two types of field olfactometers. This paper presents a correlation between dilution-to-threshold values (D/T) and hydrogen sulfide ambient concentration. For example, a D/T of 7 corresponds to ambient H2S concentrations of 5.7-15.6 μg/m3 (4-11 ppbv). During this study, no significant difference was found between results obtained using the Scentometer or the Nasal Ranger® (r = 0.82). Also, no significant difference was found between results of multiple Nasal Ranger® users (p = 0.309). The field olfactometers yielded hydrogen sulfide thresholds of 0.7-3.0 μg/m3 (0.5-2.0 ppbv). Laboratory olfactometry yielded comparable thresholds of 0.64-1.3 μg/m3 (0.45-0.9 ppbv). These thresholds are consistent with published values.

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48

Biber, Alper, Ata Can Korakci, Alexander Golick, Stephen Robinson, Gary Hayman, Justin Ablitt, Salvador Barrera-Figueroa et al. "Calibration standards for hydrophones and autonomous underwater noise recorders for frequencies below 1 kHz: current activities of EMPIR “UNAC-LOW” project". ACTA IMEKO 7, n.º 2 (4 de julio de 2018): 32. http://dx.doi.org/10.21014/acta_imeko.v7i2.542.

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The project entitled “UNderwater Acoustic Calibration standards for frequencies beLOW 1 kHz” (“UNAC-LOW”), currently active within the European Metrology Programme for Innovation and Research (EMPIR), is presented by describing its objectives and current activities. The project aims at developing the metrological capacity of the European Union (EU) for the calibration of hydrophones and autonomous recording systems for the frequency range between 20 Hz and 1 kHz, for which traceability is presently not fully available. In this way, EU metrological capacities for absolute measurement of underwater sound will be improved, with a direct effect on the implementation of regulation and EU Directives that require underwater acoustic measurements to be traceable. After having completed the initial project tasks regarding the review of existing methods and the design of the experimental setups, comparison measurements between the project partners are currently under way and their results will be validated and presented upon project end after first quarter of 2019. To ensure long-term operation of the calibration capabilities by each partner, a coherent EU metrology strategy for underwater acoustics will be developed as one of the main project outcomes. Current activities include the implementation of the calibration setups developed in earlier stages of the project for both hydrophones and autonomous recorders. The methods that shall be used for hydrophones are the pressure method in a closed chamber and the standing wave tube method. For autonomous recorders, in addition to the above methods, calibrations will be performed using free-field methods in different open-water test sites possessing suitable characteristics for low frequency measurements.

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Mittaz, Jonathan P. D., Andrew R. Harris y Jerry T. Sullivan. "A Physical Method for the Calibration of the AVHRR/3 Thermal IR Channels 1: The Prelaunch Calibration Data". Journal of Atmospheric and Oceanic Technology 26, n.º 5 (1 de mayo de 2009): 996–1019. http://dx.doi.org/10.1175/2008jtecho636.1.

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Abstract The absolute accuracy of the thermal infrared (IR) radiances and brightness temperatures derived from the Advanced Very High Resolution Radiometer (AVHRR) is still unknown, with major sources of error not yet fully understood. This is despite the fact that data from the AVHRR IR channels are widely used in deriving important atmospheric and surface parameters as well as in weather prediction, climate modeling, and other environmental studies. Central to the problem are possible errors introduced by the calibration test procedures and methodologies that can range up to approximately 0.5 K, much larger than the instrument electronic and detector noise characteristics. Further, there are known issues with the current calibration including a large mismatch of up to 0.7 K between the measured physical temperature of the internal calibration target (ICT) and its radiometric temperature estimated by using the AVHRR-observed counts. In an effort to improve this, a new approach to the calibration has been adopted that is dependent on physical instrument parameters. It is shown that this new calibration method can explain the ICT temperature mismatch as a combination of an incorrect assumption that the AVHRR was kept at a constant temperature during testing combined with the effect of scattered radiation from the test chamber and other sources. This new calibration also reduces the total biases and errors that exist when using the current operational calibration on the prelaunch data. Comparing the external calibration target temperatures to the temperatures derived using the AVHRR measurements, this new calibration can reduce an up to 0.7-K bias seen currently to an essentially zero bias with a scatter of less than 0.05 K in the SST regime. This marks an improvement of up to an order of magnitude in accuracy over the current operational calibration.

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50

Marshall, T. "Thermal Environment Simulator for Vacuum Testing of Large Spacecraft". Journal of the IEST 31, n.º 1 (1 de enero de 1988): 29–49. http://dx.doi.org/10.17764/jiet.1.31.1.01u3jk1766m20753.

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A thermal environment simulator (TES) with 56 independently controllable temperature zones has been developed for Martin Marietta's Space Simulation Laboratory. This simulator is designed to test shuttle payloads in a thermal vacuum chamber with liquid nitrogen cold walls. The thermal environment simulator is an alternative to a 4.9-m (16-tt) diameter vertical beam solar simulator and two-axis gimbal system. The simulator can accommodate larger test articles at a lower cost. It provides complex heat flux distributions by surrounding the test articles with a multifaceted temperature environment. Issues resolved during initial operation included vacuum and cryogenic compatibility, control capabilities, instrumentation, calibration, heat flux uniformity, and reliability.

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