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This article presents the findings of a systematic literature review focusing on the impact of interferences in host materials on Respirable Crystalline Silica (RCS) measurement, and the development of a validated method of calibration for RCS instrumentation for in-field use. The impact of interferences in host materials on RCS measurement has been shown to be critical information required for in-field use of portable RCS devices. Portable RCS instruments such as FTIR and XRD have been established to have good sensitivity for measurement but relatively low specificity due to interference in host materials. It has been shown that correction factors are needed to be applied to account for known interferences, especially when calibrating portable RCS instrumentation in-field. The potential to obtain reliable and repeatable results from RCS analysis instrumentation has also been demonstrated. There was significant evidence that interference materials could be present in host materials, and they influence RCS measurement. There is the potential and possibility of using portable RCS instrument for in-field measurement however the challenge is the calibration of such instrumentation in the field to account for changing host materials and thus potential interferences. [ABSTRACT FROM AUTHOR]

The API p-y method is widely used in the design of offshore wind turbines (OWTs) monopiles at present. This study systematically evaluates the model uncertainty of the p-y method for OWT monopiles and proposes a two-stage calibration approach for evaluating the model bias factor. To overcome the difficulty of limited field tests, a high-fidelity base model is employed as a bridge between the field test data to the p-y method. The field test data is used to calibrate the base model and determine the model error of the base model. Synthetic numerical cases are subsequently generated using the base model to evaluate the correction factor of the p-y method. By combining the model error of the base model and the correction factor of the p-y method, the model bias factor of the p-y method can be evaluated. The reliability analysis of the monopile in an offshore wind project in China is taken as an example. The results serve as a valuable tool for correcting the lateral bearing capacity of OWT monopiles based on the specific soil conditions and risk preferences for the offshore wind turbine project. [ABSTRACT FROM AUTHOR]

The use of Raman spectroscopy has rapidly been on the rise across a great number of industries where comparability, reproducibility, and reliability of the data are of paramount importance. However, controlling the intensity of the Raman signal depends on a large number of factors such as the wavelength of the laser light, the optical components of each device, or the number of molecules in the illuminated volume. For this reason, in this study, a new protocol has been applied to twin Raman devices to achieve a conversion of the signal between them, by pairing the intensity response of the units using a reference sample. The new reference material is a homogenous dispersion of a 0.5 wt% anatase (titanium dioxide, or TiO2) in an epoxy resin matrix, with deviations <2.5% in Raman intensity across the reference material. The proposed protocol for Raman-twinned devices takes a well-defined approach that leads to obtaining a correction factor that relates the differences in the signal intensity between the two Raman devices, in order to obtain the same Raman intensity counts. The performance of the proposed method was evaluated based on the data from the devices, which presented the most common user cases: twinning Raman devices of the non-confocal same model for two different wavelengths; and twinning confocal and non-confocal devices. The results obtained show that the protocol has worked for both of the Raman twinning cases, allowing the Raman intensity harmonization of Raman spectra between two different devices. [ABSTRACT FROM AUTHOR]

AbstractStroboscopic nutation has proved to be invaluable for pulse width calibration (P. S. C. Wu and G. Otting, Rapid pulse length determination in high-resolution NMR, J. Magn. Reson. 2005, 176, 115–119), though it is not without its issues. Herein it is proposed that a correction factor be applied to correct for the inaccuracy of the method which is dependent on the NMR system including the probe, observed nucleus, sample type set (solvent, concentration, ionic strength, etc.), temperature, etc. Poor performance of the stroboscopic nutation experiment was also found to be a harbinger of a serious hardware problem. [ABSTRACT FROM AUTHOR]

The ground‐based, high‐frequency radars of the Super Dual Auroral Radar Network (SuperDARN) observe backscatter from ionospheric field‐aligned plasma irregularities and features on the Earth's surface out to ranges of several thousand kilometers via over‐the‐horizon propagation of transmitted radio waves. Interferometric techniques can be applied to the received signals at the primary and secondary antenna arrays to measure the vertical angle of arrival, or elevation angle, for more accurate geolocation of SuperDARN observations. However, the calibration of SuperDARN interferometer measurements remains challenging for several reasons, including a 2π phase ambiguity when solving for the time delay correction factor needed to account for differences in the electrical path lengths between signals received at the two antenna arrays. We present a new technique using multi‐frequency ionospheric and ground backscatter observations for the calibration of SuperDARN interferometer data, and demonstrate its application to both historical and recent data. Key Points: Calibration of Super Dual Auroral Radar Network (SuperDARN) interferometer angle of arrival data remains an outstanding challengeAnalysis of data at multiple frequencies can overcome the inherent 2π measurement ambiguity in the time delay correction factor (tdiff)Example applications are shown for historical and contemporary multi‐frequency SuperDARN observations [ABSTRACT FROM AUTHOR]

AbstractThe laboratory measurement of the acoustic attenuation coefficient of seafloor sediment poses a significant challenge as it is more difficult to measure with the same precision and convenience as the sound velocity. A novel dual-probe acoustic measurement method (DPAMM) addresses this challenge by simultaneously obtaining the sound velocity and acoustic attenuation coefficient of seafloor sediments, enabling stratified measurements with minimal disturbances. However, issues related to the sensitivity difference between the probes, the diameter of the sample pipe, and the inter-probe blockage can affect the accuracy of the measurement. To address these influencing factors, water was used as a reference standard for calibrating DPAMM. Experimental investigations were conducted to examine the effects of factors such as the diameter of the sample pipe, probe spacing, probe distance from the acoustic source, and probe sensitivity differences. The results revealed a positive correlation between the diameter of the sample pipe and the effective measurement distance, as well as the correction factor for probe blockage. Based on the calibration method described above, sensitivity calibration coefficients and blocking correction coefficients were derived from the experiments. The application of the stratified acoustic measurement of seafloor sediment samples demonstrates the effectiveness of the DPAMM. [ABSTRACT FROM AUTHOR]

Thermogravimetric analysis (TGA) involves the measurement of the changes in mass that occur when a constant heat is applied to an unknown specimen as a function of time or temperature. It is used to evaluate thermal stability, oxidative stability, composition, and estimated lifetime, among other parameters. Given that accurate TGA data is important information for lifetime and stability evaluation of parts and products, an uncertainty evaluation procedure is required to ensure the reliability of the data. In this study, the uncertainty evaluation procedure was established according to the Guide to the Expression of Uncertainty in Measurement (GUM). The mathematically expression of the relationship between the measurand and the input quantities, evaluation of the standard uncertainty of each input estimate, determination of the combined standard uncertainty, and calculation of the expanded uncertainty were performed. The biggest factor affecting the uncertainty of TGA data is the uncertainty of correction factor caused by system calibration. [ABSTRACT FROM AUTHOR]

To enhance the accuracy and stability of FY-4A/AGRI detection data, the MODIS, with highly accurate onboard calibration, is selected as the reference sensor for cross-radiation calibration calculations. The following are the data selection conditions: full considered time, observation geometries, field angles, cloud cover, etc. FY-4A/AGRI and Aqua-MODIS image data are selected as matching sample region locations, where the time difference between the observations for the same ground object is less than 15 min, the satellite zenith angle is less than 30°, and the field angle difference is less than 0.01. The 245 collected reflectance spectral curves are convolved with the spectral response functions of the two sensors, and the spectral band adjustment factors of the corresponding bands are calculated for spectral correction purposes. The cross-calibration coefficients for the red and near-infrared bands are calculated by linearly fitting the simulated top of the atmosphere reflectance values and digital number values from the AGRI sensor in a homogeneous area. In this paper, 16 cross-calibration calculations are performed on FY-4A/AGRI image data from August 2018 to September 2020, and the results are compared with the original calibration coefficients to test the feasibility of the proposed method. Additionally, 31 cross-calibration calculations are performed on image data from October 2020 to December 2022 to study the resulting AGRI sensor quality and performance changes. The NDVI of the FY-4A/AGRI image data was calculated before and after the cross-radiometric calibration using the maximum synthesis method. Additionally, the NDVI of the MODIS image data was compared and analyzed from three aspects: time, space, and the change trend. The results show that the spectral band adjustment factor calculated using the reflectance spectral curves of the ground objects in this paper can effectively correct for the spectral differences between the two sensors. Sixteen cross-calibration coefficients are less than 5.2% different from the original calibration coefficients, which fully proves the feasibility of the method used in this paper. All of the cross-calibration results show that the AGRI sensors have a certain degree of attenuation in the red and near-infrared bands, and the annual attenuation rates are approximately 1.37% and 2.55%, respectively. Cross-radiometric calibration has further improved the quality of the NDVI in FY-4A/AGRI imagery, enhancing the precision of its data application. [ABSTRACT FROM AUTHOR]

Aiming at the problem of large measurement error and phase shift in resistance voltage dividers under high-frequency conditions in the field of power measurement, such as power harmonics, an error correction method is proposed for an alternating current (AC) resistance voltage divider based on the equivalence principle. Firstly, the frequency error model of the AC resistance voltage divider precision is established, and the angle difference of the continuous spectrum ratio difference from 50 Hz to 100 kHz is corrected by determining the shielding structure and the resistance parameters and fine-tuning the shielding potential correction method to reduce the capacities error of the AC resistance voltage divider design precision. At the same time, the performance parameters such as the direction and magnitude of the shielding potential compensation capacitive error are investigated. Finally, the precision voltage divider (the maximum voltage applied is 480 V) calibration experiments verify that the important characteristic judgment factor of the voltage divider is independent of the frequency and the equivalent capacitance value, which effectively solves the phase correction problem of harmonic power measurement. [ABSTRACT FROM AUTHOR]

Low-cost particulate matter (PM) sensors continue to grow in popularity, but issues such as aerosol sizedependent sensitivity drive the need for effective calibration schemes. Here we devise a time-evolving calibration method for the Plantower PMS5003 PM2.5 mass concentration measurements. We use 2 years of measurements from the Berkeley Environmental Air-quality and CO2 Network sensors deployed in San Francisco and Los Angeles in our analysis. The calibration uses a hygroscopic growth correction factor derived from k-Köhler Theory, where the calibration parameters are determined empirically using EPA AQS reference data at co-location sites during the period from 2021--2022. The parameters are found to vary cyclically through the seasons, and the seasonal cycles match changes in sulfate and elemental carbon PM composition fractions throughout the year. In both regions, the seasonal RH dependence calibration performs better than the uncalibrated data and data calibrated with the EPA's national Plantower calibration algorithm. In the San Francisco Bay Area, the seasonal RH dependence calibration reduces the RMSE by ~40% from the uncalibrated data and maintains a mean bias much smaller than the EPA National Calibration scheme (--0.90 vs --2.73 µg/m³). We also find that calibration parameters forecasted beyond those fit with the EPA reference data continue to outperform the uncalibrated data and EPA calibration data, enabling real-time application of the calibration scheme even in the absence of reference data. While the correction greatly improves the data accuracy, non-Gaussian distribution of the residuals suggests that other processes besides hygroscopic growth can be parameterized for future improvement of this calibration. [ABSTRACT FROM AUTHOR]

Low-cost particulate matter (PM) sensors continue to grow in popularity, but issues such as aerosol size-dependent sensitivity drive the need for effective calibration schemes. Here we devise a time-evolving calibration method for the Plantower PMS5003 PM2.5 mass concentration measurements. We use 2 years of measurements from the Berkeley Environmental Air-quality and CO2 Network sensors deployed in San Francisco and Los Angeles in our analysis. The calibration uses a hygroscopic growth correction factor derived from k-Köhler Theory, where the calibration parameters are determined empirically using EPA AQS reference data at co-location sites during the period from 2021–2022. The parameters are found to vary cyclically through the seasons, and the seasonal cycles match changes in sulfate and elemental carbon PM composition fractions throughout the year. In both regions, the seasonal RH dependence calibration performs better than the uncalibrated data and data calibrated with the EPA's national Plantower calibration algorithm. In the San Francisco Bay Area, the seasonal RH dependence calibration reduces the RMSE by ~40 % from the uncalibrated data and maintains a mean bias much smaller than the EPA National Calibration scheme (–0.90 vs –2.73 µg/m3). We also find that calibration parameters forecasted beyond those fit with the EPA reference data continue to outperform the uncalibrated data and EPA calibration data, enabling real-time application of the calibration scheme even in the absence of reference data. While the correction greatly improves the data accuracy, non-Gaussian distribution of the residuals suggests that other processes besides hygroscopic growth can be parameterized for future improvement of this calibration. [ABSTRACT FROM AUTHOR]

The purpose of this work was to provide guidance for the lack of an air-kerma rate standard for the S7600 Xoft Axxent® source by providing a correction factor to apply to the National Institute of Standards and Technology (NIST) traceable S7500 well chamber (WC) calibration coefficient before the development of an S7600 standard at NIST. The Attix free air chamber (FAC) at the University of Wisconsin Medical Radiation Research Center was used to measure the air-kerma rate at 50 cm for six S7500 and six S7600 sources. These same sources were then measured using five standard imaging HDR1000+ WCs. The measurements made with the FAC were used to calculate source-specific WC calibration coefficients for the S7500 and S7600 source. These results were compared to the NIST traceable calibration coefficients for the S7500 source. The average results for each WC were then averaged together, and a ratio of the S7600 to S7500 WC calibration coefficients was determined. The average S7600 air-kerma rate measurement with the FAC was 7% lower than the average air-kerma rate measurements of the S7500 source. On average, the S7500 determined WC calibration coefficients agreed within ±1% of the NIST traceable S7500 values. The S7600 WC calibration coefficients were up to 16% less than the NIST traceable S7500 values. The final correction factor determined to be applied to the NIST traceable S7500 value was 0.8415 with an associated uncertainty of ±8.1% at k = 2. This work provides a suggested correction factor for the S7600 Xoft Axxent source such that the sources can be accurately implemented in the clinical setting. [ABSTRACT FROM AUTHOR]

A cost‐effective way of undertaking comprehensive, continental‐scale, assessments of ecological condition is needed to support large‐scale conservation planning, monitoring, reporting, and decision‐making. Currently, cross‐jurisdictional inconsistency in assessment methods limits the capacity to scale‐up monitoring. Here we present a novel way to build a coherent continent‐wide site‐level ecological condition dataset, using cross‐calibration methods to integrate assessments from many observers. We focus on the use of condition assessments from individual expert observers, a currently untapped resource. Our approach has two components: (1) a simple online tool that captures expert assessments at specific locations; (2) a process of calibrating and rescaling disparate expert evaluations that can be applied to the data to provide a consistent dataset for use in conservation assessments. We describe a pilot study, involving 28 experts, who contributed 314 individual site condition assessments across a wide range of ecosystems and regions throughout continental Australia. A correction factor for each expert was used to rescale the contributed site condition assessment scores, based on a set of 77 photographic images, each scored for their condition by multiple experts, using a linear mixed model. Our approach shows strong promise for delivering the volumes of data required to develop continental‐scale reference libraries of site condition assessments. Although developed from expert elicitation, the approach could also be used to harmonize the collation of existing condition datasets. The process we demonstrate can also facilitate online citizen scientists to make site condition assessments that can be cross‐calibrated using contributed images. [ABSTRACT FROM AUTHOR]

The paper presents experimental data that show the possible application of a piezo actuator in the role of calibration standard that can serve as an alternative route to currently available methods like gauge blocks or flick standards. First, the experimental setups for interferometric and roundness instruments measurements were described. Next, the experiments using an interferometer for calibration of the piezo actuator were shown. Finally, the application of a piezo actuator to calibrate the roundness instrument, to state the correction factor for the roundness probe, and to relate it to the unit of metre, assuring the traceability of future measurements was performed. Detailed procedures of simulating grooves and then processing the data were described and the calibration curve was obtained using regression analysis. The estimation of uncertainty provided by different factors during the measurements was given to fulfil as closely as possible real calibration procedures taken up in the measurement laboratories. Finally, the limitations of the presented procedures were presented and discussed. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to develop an algorithm that corrects the image of an electronic portal imaging device (EPID) of a linear accelerator so that it can be used for dosimetric purposes, such as in vivo dosimetry or quality assurance for photon radiotherapy. For that purpose, the impact of the field size, phantom thickness, and the varying spectral photon distribution within the irradiation field on the EPID image was investigated. Methods: The EPID measurements were verified using reference measurements with ionization chambers. Therefore, absolute dose measurements with an ionization chamber and relative dose measurements with a detector array were performed. An EPID calibration and correction algorithm was developed to convert the EPID image to a dose distribution. The algorithm was validated by irradiating inhomogeneous phantoms using square fields as well as irregular IMRT fields. Results: It was possible to correct the influence of the field size, phantom thickness on the EPID signal as well as the homogenization of the image profile by several correction factors within 0.6%. A gamma index analysis (3%, 3 mm) of IMRT fields showed a pass rate of above 99%, when comparing to the planning system. Conclusion: The developed algorithm enables an online dose measurement with the EPID during the radiation treatment. The algorithm is characterized by a robust, non‐iterative, and thus real‐time capable procedure with little measuring effort and does not depend on system‐specific parameters. The EPID image is corrected by multiplying three independent correction factors. Therefore, it can easily be extent by further correction factors for other influencing variables, so it can be transferred to other linear accelerators and EPID configurations. [ABSTRACT FROM AUTHOR]

The purpose of this study is to characterize the positional accuracy of the multileaf collimator (MLC) using an ionization chamber array and develop an MLC quality assurance (QA) method. Half of the volume for each ionization chamber located at the lower layer of the device was occluded by a specific leaf using the half-beam block (HBB) method, and the corresponding ionization chamber response was used as a baseline for the subsequent MLC QA study. The sensitivity of the method was assessed by introducing known leaf positional errors, varying from 0.5 to 2.5 mm in 0.5 mm increments in the positive and negative directions, into the baseline. The relative outputs of the detectors were linearly corrected according to the leaf position error recorded. The relationship between detector response variation relative to the baseline and the introduced leaf error was determined by function. The usefulness of the MLC QA technique developed in this study was verified weekly over 5 months. During the development of the algorithm, the maximum leaf absolute random position error was 0.3 mm. A strong linear relationship was observed between the relative output of the detector and the MLC positional error introduced, and the slope and coefficient of determination were −0.05159 and 0.99928, respectively. The mean MLC positional accuracy across all leaves for the error field and HBB baseline field over the 5-month assessment was 0.0649 ± 0.1340 mm and 0.0002 ± 0.0835 mm, respectively. The automated MLC QA procedure we proposed has proven to be effective and robust, and satisfies the American Association of Physicists in Medicine (AAPM) Task Group Report 198 guideline criteria of ± 1 mm. • Multiple MLC calibrations in a single measurement. • The ionization chamber readings are not affected by other beams using an automatic data acquisition and storage program. • Development of MLC calibration methods using log files. • A calibration curve is established for each leaf with two correction factors. [ABSTRACT FROM AUTHOR]

The measurement of gamma emitters natural radionuclides is a very relevant subject in environmental radioactivity in many fields. For this, a valid calibration based on the full-energy peak efficiency (FEPE) is essential, which can be carried out for gamma-ray spectrometry using Monte Carlo codes (Geant4, LabSOCS, MNCP, etc.) without needing a source preparation and with much less time consuming compared to experimental methodologies. Therefore, this work aims to develop a methodology for the FEPE determination of uncharacterized Ge detectors by using characterized Ge detectors with known FEPE. For this, a general relationship was found between the simulated FEPE (ε sim ) for characterized Ge detectors by LabSOCS and the experimental one (ε exp ) for uncharacterized Ge detectors obtained for a problem sample (phosphate rock (PR) in our case), where ε sim and ε exp were factorized using three correction factors: geometrical, photon self-absorption and true coincidence summing (TCS) effects. Thus, the ε sim / ε exp ratio (FEPER) was obtained for two couples of Ge detectors (2 characterized and 1 uncharacterized detectors), using 4 different cylindrical geometries (C) and 2 Marinelli (M) ones, and varying the sample thickness (h), and gamma energy (E γ) (from 46 keV (210Pb) to 1765 keV (214Bi)). The consistency obtained for the FEPER s for C geometries suggested a constant geometric factor, finding some deviations for M geometries only at E γ < 150 keV. Given a pair of detectors, the behavior of the FEPER s was found to be very similar for all geometries, and h at each specific E γ. Moreover, a constat relationship between the FEPERs of both detector couples versus E γ was found. Then, the influence of the TCS effects was also studied varying the distance between the geometry bottom and detector window. The developed methodology was also validated confirming the consistency of the FEPERs , which were found to be independent on the chemical composition and apparent density of the sample, supporting our theoretical hypothesis. Consequently, given that the FEPER was found to be independent on the sample type and h , using our developed methodology it is possible to obtain ε exp for any sample, geometry and h using the FEPER , previously obtained at each E γ for the sample selected for methodology development (PR in our case), and the ε sim that is obtained for the desired case. • A novel efficiency calibration method for uncharacterized Ge detectors using characterized Ge detectors was developed. • For this, the full-energy peak efficiency ratio (FEPER) of the characterized and uncharacterized detectors was obtained. • A general FEPER function was found varying the sample thickness (h), energy (E γ) and geometry type. • The FEPERs were found to be independent on the sample thickness and type, and geometry. • The robustness and validity of this methodology were tested for a wide range of h , E γ , sample types and geometries. [ABSTRACT FROM AUTHOR]

Consumer-grade electronic radon monitors are increasingly utilized by users and researchers. Fast and cost-effective procedures for their metrological assurance are necessary. The metrological characteristics of 20 RadonEye Plus2 monitors were investigated. The new monitors had low background of 2.5 ± 0.5 Bq/m3. The precision error for the studied group was estimated at about 9 % and the biased error (accuracy) ranged from 3 % to 16 % for activities in the range 280–2900 Bq/m3. An excellent linearity of all monitors was observed in this range. The statistical fluctuations of the RadonEye Plus2 at 300 Bq/m3 were estimated at 9% (relative percent error). A simplified calibration procedure was successfully applied. The exposure was at activity concentration exponentially increasing with a small rate, being almost constant within a single measurement of the RadonEyes. The correction factors obtained with this procedure are in excellent agreement with those obtained through the standard procedure with exposure at different constant radon concentrations. The correction factors of the monitors ranged from 0.70 to 1.06 with an average of 0.880 and a standard deviation of 0.079. Overall, the results show that the metrological characteristics of RadonEye Plus2 are sufficient for measurements in dwellings and workplaces. However, the spread of their correction factors highlights the importance of individual calibration when measurements are made for research, legislation compliance tests or decision making. • Consumer-grade radon monitors need calibration, but procedures are costly. • A simplified exposure regime was tested with potential for in-situ calibration. • 20 calibrated RadonEye +2 had correction factors from 0.70 to 1.06 (0.88 average). • The group had 9 % precision error and <16 % biased error for 280–2900 Bq/m3 radon. • The new RadonEyes +2 had low background and good linearity for 280–2900 Bq/m3. [ABSTRACT FROM AUTHOR]

The prediction of heat transfers in Reynolds-Averaged Navier–Stokes (RANS) simulations requires corrections for rough surfaces. The turbulence models are adapted to cope with surface roughness impacting the near-wall behaviour compared to a smooth surface. These adjustments in the models correctly predict the skin friction but create a tendency to overpredict the heat transfers compared to experiments. These overpredictions require the use of an additional thermal correction model to lower the heat transfers. Finding the correct numerical parameters to best fit the experimental results is non-trivial, since roughness patterns are often irregular. The objective of this paper is to develop a methodology to calibrate the roughness parameters for a thermal correction model for a rough curved channel test case. First, the design of the experiments allows the generation of metamodels for the prediction of the heat transfer coefficients. The polynomial chaos expansion approach is used to create the metamodels. The metamodels are then successively used with a Bayesian inversion and a genetic algorithm method to estimate the best set of roughness parameters to fit the available experimental results. Both calibrations are compared to assess their strengths and weaknesses. Starting with unknown roughness parameters, this methodology allows calibrating them and obtaining between 4.7% and 10% of average discrepancy between the calibrated RANS heat transfer prediction and the experimental results. The methodology is promising, showing the ability to finely select the roughness parameters to input in the numerical model to fit the experimental heat transfer, without an a priori knowledge of the actual roughness pattern. [ABSTRACT FROM AUTHOR]

Small fission chambers manufactured by Photonis, Reuter-Stokes, CEA, and Centronic are routinely calibrated in standard neutron fields of the BR1 reactor at SCK CEN in Mol, Belgium. Two irradiation fields are available: fast spectrum in the MARK3 convertor and thermal spectrum in the Empty Cavity. In this work, for the first time the calibration procedure of larger fission chambers (Photonis CFUL01 and CFUM21 type) with the deposit length exceeding the length of the convertor is presented. Spatial energy correction factors taking into account the neutron flux shape beyond the convertor and radial gradient of the neutron flux were calculated with MCNP and experimentally validated. The combination of calibration (i.e., effective mass measurement) in fast and thermal irradiation fields allows for determination of the purity of 238U deposit. This is demonstrated on three CFUL01-type fission chambers with purity between 99.8% and 99.998%. [ABSTRACT FROM AUTHOR]

The H *(10) and E (Ω) responses to photons from 15 to 1253 keV were determined as a function of source orientation for the 7LiF:Mg,Cu,P 'body' and 'skin' elements of a thermoluminescence dosemeter optimized to measure H p (10) and H p (0.07), and are presented here relative to the results from 662 keV calibration exposures. The calculations were performed using the Monte Carlo transport code MCNP6.2, with the dosemeter located either free-in-vacuo or on a concrete wall; the impacts of the radiation field and dosemeter mounting are discussed. The relative response profiles were found to be fairly flat at energies above a few 10s of keV, leading to the conclusion that the personal dosemeter may be used in some environmental or workplace fields to provide reasonable estimates of ambient dose equivalent and effective dose; the latter is additionally relevant given the newly proposed operational quantity ambient dose (H *). Optimal correction factors were also derived that allow the dosemeter's standard H p (d ,0°,137Cs) system calibrations to be maintained. • The H *(10) and E (Ω) responses of a personal TLD are determined for photons by Monte Carlo modelling. • Calculated responses are energy-dependent, but also depend on the exposure geometry and location of the dosemeter. • Correction factors were derived that allow the standard system calibration to H p (d ,Cs) to be maintained. • The TLD performance was satisfactory across the energy range, and also complies with the BS EN IEC 62387 Standard. • Determining the E (Ω) response 'future-proofs' the TLD for assessing H * doses in the workplace or environment. [ABSTRACT FROM AUTHOR]

With the aerospace and aviation industry development, machining deformation is the most prominent and urgent problem in the production process. Studies have shown that initial residual stress (RS) is the main factor causing the deformation of this type of part. Since residual stresses must be analyzed quantitatively, a series of measurement methods have been developed for this purpose. Remarkably, a series of measurement technologies inevitably need to include the corresponding calibration process, which is the fundamental element to ensure RS measurement accuracy. In this investigation, we developed a non-contact stress calibration method based on deflection value to study the measurement deviation of forging residual stress in the aerospace field. The constant stress beam (CSB) mechanical and finite element models of Ti6Al4V titanium alloy were established. The deflection measurement method was implemented using the visual system based on pattern speckle technology. A high precision loading device was developed to provide an accurate external load for CSB. A novel calibration technology based on the deflection method was proposed to realize RS measurement's calibration process. We have successfully applied the CSB bending test campaigns and deflection metrology method to calibrate the stress values measured by the Static strain measuring instrument of Sigma and the Stress measuring instrument of Proto-ixrd. The results of theoretical and simulation stress are highly consistent with the calibration experiment. Calibration experiments combining the pattern speckle technology and the deflection method allow the stress measurement process's calibration according to the correction factor. The research provides a great impetus to the development of precise quantitative measurement of RS. [ABSTRACT FROM AUTHOR]

Accurate dose measurement is very important for diagnosing X-ray equipment. These equipment should be traced directly or indirectly to primary standard with as little uncertainty as possible. A parallel-plate free-air chamber was designed to measure air kerma of diagnostic X-ray absolutely. Different thickness of aluminium filters were used to obtain different radiation qualities according with IEC 61267. Correction factors were obtained by experiments and simulation, especially the air attenuation factor measured with vacuum method. The relative standard uncertainty of air kerma rate measurement was 0.46% and calibration factor was 0.53%. A transfer ionisation chamber was calibrated with Radiation Qualities in Radiation beams (RQR) qualities in National Research Council of Canada and National Institute of Metrology (NIM), the differences of calibration factors are less than 0.68%. [ABSTRACT FROM AUTHOR]

The Earth-observing Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) satellite regularly performs on-orbit radiometric calibration of its reflective solar bands (RSBs), primarily through observations of an onboard sunlit solar diffuser (SD). The on-orbit change of the SD bidirectional reflectance distribution function (BRDF) value, quantified by a numerical factor called the H-factor, is determined by the onboard SD stability monitor. Our previous study showed that the H-factor is solar angle- and view direction-dependent. In this study, we determine the dependence of the H-factor on the detector SD view footprint location. We fit an empirical model to the NASA Collection 1 SNPP VIIRS Level 1B (L1B) spectral reflectance difference across the detectors in an RSB over uniform Earth scenes of the Libya 4 desert and deep convective clouds (DCCs). We apply the model predicted SD-positional-dependent H-factor to calibrate the RSBs. Under this new calibration scheme, the original unreal striping is removed from the homogeneous Libya 4 desert and the DCC images, as well as the original unreal striping from the Dunhuang desert image. The SD-positional-dependent H-factor has been used to calculate the SNPP VIIRS RSB radiometric correction factor for the NASA Collection 2.0 SNPP VIIRS L1B products. [ABSTRACT FROM AUTHOR]

The hole-drilling strain-gauge method is a common residual stress evaluation approach, where the calibration coefficients are one of the main factors affecting their measurement accuracy. However, those coefficients are the constant value for ASTM E837-13a, Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gauge Method, which does not allow for the Poisson's ratio effect. The finite element method to calculate the calibration coefficients was first proposed, then the Poisson's ratio effect on them was studied. The results show that the calibration coefficients a ¯ jk increase and b ¯ jk decrease with Poisson's ratio exhibiting a good linear relationship. The Poisson's ratio correction factor was introduced to calculate calibration coefficients for any Poisson's ratio, those values (v0) offer an improvement in the versatility of a given calibration coefficient. The problem of the Poisson's ratio effect on the calibration coefficients was solved, and their accuracy was improved due to the use of the hole-drilling strain-gauge method. [ABSTRACT FROM AUTHOR]

We show that if all the line and bus CVTs within a substation are monitored by PMUs, then it is possible to perform CVT calibration locally. This requires 1) discovery of a set of three phase CVTs which can be used as the reference and 2) calculation of ratio correction factors. We show that the best set of three phase CVTs among the redundant sets can be discovered by minimizing the overall measured unbalance among all the three phase CVT combinations. All the CVTs measure the same bus voltage time series. Hence, the corresponding phase measurement matrix will be a small modification of a rank-1 matrix; each column is a scaled replica of the true voltage vector modified by white noise. A microscopic evaluation of the substation PMU data shows that rank-1 approximation by SVD retains 99.99% information. The magnitude correction factors can be obtained by projecting CVT measurement vectors on the first left singular vector. Phase angle correction factors correspond to angles of elements of the first right singular vector. Results with both simulated and field PMU data of 400 kV substations substantiate the claims made. [ABSTRACT FROM AUTHOR]

The value of the personal dose equivalent at a 10 mm depth is to characterize the energy deposition of strong penetrating radiation in the human body and is derived by measurement of air kerma and application of conversion coefficients from the ISO report. However, the conversion coefficients depend strongly on the photon energy and angles of incidence for low-energy photons. In order to overcome the problem that the conversion coefficient of low energy rays changes greatly due to the small change of energy, a secondary standard ionization chamber was used to measure the personal dose equivalent directly. A matched reference field was established with 20-250 kV X-rays and correction factors with the Hp(10) chamber were calculated under these radiation qualities with different angles of incidence. The results showed that the differences were almost 22.7% of correction factors for the low energy photons at angles of incidence 0°. With the conversion coefficient recommended in ISO 4037-3-2019, the performance of the chamber response with respect to Hp(10) in the energy range from 33 keV to 208 keV was within about ±10%, and in the energy range from 12 keV to 208 keV and for angles of incidence between 0° and 75° was within about ±19%. [ABSTRACT FROM AUTHOR]

The use of atomic force microscopy in nanomechanical measurements requires accurate calibration of the cantilever's spring constant (kc) and the optical lever sensitivity (OLS). The thermal method, based on the cantilever's thermal fluctuations in fluids, allows estimation of kc in a fast, non-invasive mode. However, differences in the cantilever geometry and mounting angle require the knowledge of three correction factors to get a good estimation of kc: the contribution of the oscillation mode to the total amplitude, the shape difference between the free and end-loaded configurations, and the tilt of the cantilever with respect to the measured surface. While the correction factors for traditional rectangular and V-shaped cantilever geometries have been reported, they must be determined for cantilevers with non-traditional geometries and large tips. Here, we develop a method based on finite element analysis to estimate the correction factors of cantilevers with arbitrary geometry and tip dimensions. The method relies on the numerical computation of the effective cantilever mass. The use of the correction factor for rectangular geometries in our model cantilever (PFQNM-LC) will lead to values underestimated by 16%. In contrast, experiments using pre-calibrated cantilevers revealed a maximum uncertainty below 5% in the estimation of the OLS, verifying our approach. [ABSTRACT FROM AUTHOR]

To evaluate a pipe network performance, both steady and unsteady flow conditions are required to be accurately analyzed in the system. For this purpose, mathematical models are developed and utilized. Calibration of parameters with dynamic effects like the steady and unsteady friction loss factors as well as pipe wave speed is crucial to the simulation models. A common approach for calibration of pipe networks under unsteady flow is the Inverse Transient Analysis (ITA) method. This study introduces a model for hydraulic analysis of unsteady flow in pressurized pipes using the numerical Method of Characteristics (MOC). To each calibration parameter a correction factor is specified. Then, a nonlinear optimization problem is developed with the aim of minimizing the discrepancy between the calculated and measured transient pressure heads at the measurement sites. The decision variables are the correction factors multiplied by the pipe wave speeds, steady friction factors and unsteady friction loss components. In this Article, the proposed model applied to an experimental system set up in the Technical University of Lisbon. By defining the genetic algorithm to minimize the objective function, after 30 generations error rate was reduced from 140 m to 92.15 meters. The results, increasing the accuracy of modeling showed as much as 33%.

Background: The increased use of ionizing radiation for diagnostic purpose has resulted in an increase in the world population dose. Patient dosimetry in X-ray diagnostic radiology is required to establish diagnostic reference levels (DRLs) and to assess the average dose received by organs and tissues. International bodies have recommended DRLs to be based on dosimetric quantities. Aim: To cater to the increased requirement for dosimetry in diagnostic radiology, international guidelines are provided to establish and disseminate traceable calibration for dosimeters used in X-ray diagnostic radiology. X-ray diagnostic beams established are standardized using a diagnostic range free-air ionization chamber (DFAIC) (20-150 kV). Materials and Methods: Characterization of the DFAIC and determination of the correction factors for the air kerma measurements were evaluated experimentally and by theoretical calculations. Results: The paper details the establishment of 18 diagnostic beam qualities using DFAIC along with the associated uncertainties. The overall uncertainty for the air kerma measurements was within ±0.5% at 1 sigma level. Eight diagnostic range air kerma measurements using DFAIC were compared with the medium energy primary standard FAIC (50-300 kV) maintained in the laboratory. Conclusion: The air kerma rates agreed within ±1% and are within the overall standard uncertainty of both the chambers at the time of the comparison. Dissemination to the users in the field of diagnostic radiology in the country has been carried out by calibrating their ionization chambers and solid-state detector-based instruments against the DFAIC. The methodology followed to standardize the beams using DFAIC and calibration of dosimeters is presented in this work. [ABSTRACT FROM AUTHOR]

Copyright of Mediterranean Agricultural Sciences is the property of Akdeniz Universitesi Ziraat Fakultesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of Nanjing University of Aeronautics & Astronautics is the property of Editorial Department of Journal of Nanjing University of Aeronautics & Astronautics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background. The use of ionisation chamber and thermoluminescent dosimeter (TLD) for patient dosimetry are well established. Aim and objectives. The aim was to compare the entrance surface air kerma (ESAK) between MTS-N (LiF: Mg, Ti) chips and ionisation chamber by exposing them to same dose. The purpose is to use the TL chips as a tool for patient dosimetry/audit in diagnostic radiology. In addition, homogeneity and element correction factor (ECF) of the selected chips were determined. Material and methods. TL chips were annealed at 400°c for one hour and allowed to cool and were further heated to a temperature of 100°c for another two hour usings a TLD Furnace Type LAB-01/400. The calibrated DCT-10mm ionisation chamber was positioned on a plastic container filled with water, 10cm thick at source to image distance (SID) of 1m for a 10 × 10cm2 field size. The same procedure was used for the TL chips, which were carefully placed in a transparent nylon on the plastic container as well. Exposures were made to 10mGy. MagicMax software was used to display the ion-chamber ESAK. A RadPro Cube 400 manual TLD reader was used to determine corresponding TL signal and predetermined calibration factor (CF). The unexposed chips were subtracted from exposed ones and were multiplied with the appropriate backscatter factor (BSF) to determine TL ESAK. Results. There was good exposure reproducibility from the X-ray unit, with coefficient of variation (CV) of 0.12%. The maximum uniformity index of the chips was 24.18%, which was below the 30% limit. The ECF for the ten (10) selected TL chips ranged from 0.9-1.1, which was within accepted limit (0.8-1.2). The maximum deviation of the TL chips to the ion-chamber was -9%, which was < ± 10%, while 70% of the % deviation were < ± 5%. The mean dose of TL chips was 10.02±0.48mGy, with accuracy of 0.2%. Conclusion. The MTS-N (LiF: Mg, Ti) chips from this study yielded positive results when compared to ionisation chamber measurement at low dose. [ABSTRACT FROM AUTHOR]

The problems of measuring viscosity using Brookfield viscometers directly in vessels with controlled liquids without transferring into a special measuring tank are considered. To increase the accuracy of viscosity measurements in vessels of arbitrary shape and size, experimental and theoretical studies of the LVF Brookfield viscometer sensitivity to the influencing values were carried out, which are the diameter of the vessel with a liquid, the distance from the spindle to the bottom of the vessel, and the immersion level of the spindle. A general characteristic of the factors influencing the accuracy of viscosity measurements is given. Based on the known formulas for rotational viscometers, equations for approximating the dependences of the viscometer readings on the diameter of the vessel and the distance from its bottom to the end of the spindle are derived. Formulas that allow making corrections to the measurement results when the mentioned influencing values change are obtained. The correction factors necessary for measuring viscosity in vessels, the sizes of which differ from the recommended ones, are determined. It was found that the distance from the spindle to the bottom of the vessel with the liquid affects the measurement results only when using the LV1 spindle and the immersion level affects only when using the LV4 spindle. The results of the viscometer calibration using viscosity standard samples REV-100, REV-300, REV-1000, Brookfield 12500, Brookfield 100000 are presented. A correction factor for the case of using the LV3 spindle without a guard leg was obtained. The research results presented in the article allow measuring viscosity with a Brookfield viscometer in vessels with diameters up to 40, 30, 23, 10 mm for spindles LV1, LV2, LV3, LV4, respectively. [ABSTRACT FROM AUTHOR]

Milk yield is a fundamental observation in most dairy experiments and is commonly determined using integrated milk meters that measure milk weight as the cow is being milked. These meters are heavily used in a harsh environment and often are not regularly calibrated, so calibration errors and mechanical problems may create artificial variation in milk weight data. Additionally, direct calibration by collection of milk in a bucket is difficult and imperfect because the use of the bucket may affect yield recorded by the milk meter. The objective of this work was to define a method to easily check parlor meter precision and adjust milk weight values for variation between individual stalls in a parlor. Because most cows are milked in a different stall at each milking, it has been proposed that stall deviations that represent the fixed effect of stall on milk weight could be statistically determined. Individual milk weights from 14 milkings across 7 d from approximately 200 cows were collected from the Penn State dairy farm, which is equipped with a double-10 herringbone parlor with an Afimilk 2000 milking system (S.A.E. Afikim, Afikim, Israel). Milk yield was measured automatically by in-line flow through milk meters (Afi 200; S.A.E. Afikim). The effect of stall on milk weight was modeled using a mixed model that included the fixed effect of stall and the random effects of day, milking time, and cow. First, stall deviations were calculated as the stall least squares means (LSM) minus the average LSM to identify malfunctioning meters requiring service (e.g., deviation exceeding 1 kg). A correction factor for each stall was then generated by dividing the LSM of each stall by the average LSM. Milk yields were then corrected by multiplying the meter weight value by the correction factor. To determine the effect of the correction, raw and corrected meter values were compared with weight of milk collected in a bucket (n = 3/stall). The corrected values had a 5% greater coefficient of determination than raw meter values (0.89 vs. 0.84) and had a lower average percent difference from the bucket milk weight compared with raw meter values (12.6% vs. 13.5%). The method was then used in 3 experiments with 121, 140, and 683 milk yield observations. In all data sets, correcting milk weights slightly improved model fit and had minimal effect on model term standard errors. However, this validation was completed in a parlor where the method was routinely used to identify stalls requiring service; the effect of stall corrections is expected to be larger in parlors without frequent monitoring. Stall deviations are expected to be due predominantly to calibration of the meter but also could be due to differences in pulsation or other stall-specific factors that result in a change in milk yield. It is important to account for these other sources of milk weight variation that are unrelated to treatment. Modeling the effect of stall is a simple, convenient, and low-cost method to monitor and improve milk meter precision and functionality and can be used to reduce artificial variation and experimental error. [ABSTRACT FROM AUTHOR]

Currently, the American Association of Physicists in Medicine (AAPM) TG-21 is the conventional protocol currently used for the calibration of the Leksell Gamma Knife® (LGK) (despite the publication of the AAPM TG-51 protocol). However, this protocol is based on the air-kerma standards requiring an elaborate conversion process resulting in an increase in the possibility of errors in the clinic. The International Atomic Energy Agency (IAEA) Technical Reports Series (TRS)-483 Code of Practice provides new recommendations on the dosimetry of small static fields and correction factor data for the calibration of the LGK unit. The purpose of this study is to experimentally validate previously calculated factors for the calibration of the LGK Perfexion/Icon unit in the context of the TRS-483 protocol. An experimental comparison between three protocols (TG-51, TG-21 and TRS-483 with the aforementioned correction factors) for calibration of the LGK unit is provided. Dose-rate measurements were performed on a LGK Icon unit using three ionization chambers and three phantoms with different orientations of the chambers with respect to the LGK unit. The dose rate was determined following the three calibration protocols. The standard deviation on the mean dose rate over all phantoms and chambers in different orientations determined using TG-51, TG-21 and TRS-483 protocols were 0.9%, 0.5% and 0.4%, respectively. The mean dose rate calculated using TG-51 protocol was 1.6% and 1.2% lower comparing to the TG-21 and TRS-483 protocols respectively. Applying the values calculated in Mirzakhanian et al (2018) to the measured dose rates in LGK unit for all chambers and phantoms resulted in dose rates that are consistent to within 0.4%. The TRS-483 protocol improves the consistency of the results especially when the chamber was positioned in different orientations with respect to the LGK (from 1.6% when using TG-51 or TG-21 protocols to 0.2% when using TRS-483 protocol) since the other protocols do not correct for the different chamber orientations. [ABSTRACT FROM AUTHOR]

Linac calibration is done in water, but patients are comprised primarily of soft tissue. Conceptually, and specified in NRG/RTOG trials, dose should be reported as dose‐to‐muscle to describe the dose to the patient. Historically, the dose‐to‐water of the linac calibration was often converted to dose‐to‐muscle for patient calculations through manual application of a 0.99 dose‐to‐water to dose‐to‐muscle correction factor, applied during the linac clinical reference calibration. However, many current treatment planning system (TPS) dose calculation algorithms approximately provide dose‐to‐muscle (tissue), making application of a manual scaling unnecessary. There is little guidance on when application of a scaling factor is appropriate, resulting in highly inconsistent application of this scaling by the community. In this report we provide guidance on the steps necessary to go from the linac absorbed dose‐to‐water calibration to dose‐to‐muscle in patient, for various commercial TPS algorithms. If the TPS does not account for the difference between dose‐to‐water and dose‐to‐muscle, then TPS reference dose scaling is warranted. We have tabulated the major vendors' TPS in terms of whether they approximate dose‐to‐muscle or calculate dose‐to‐water and recommend the correction factor required to report dose‐to‐muscle directly from the TPS algorithm. Physicists should use this report to determine the applicable correction required for specifying the reference dose in their TPS to achieve this goal and should remain attentive to possible changes to their dose calculation algorithm in the future. [ABSTRACT FROM AUTHOR]

The use of empirical agrometeorological models that can be adjusted to the climatic conditions of different regions has become increasingly necessary to improve water management in grain-producing municipalities. The aim of this work is to examine the correlation between various reference evapotranspiration (ETo) estimation methods and the standard FAO 56 Penman-Monteith method, as well as to determine correction factors, when necessary, for crop-producing municipalities in the northeast of Pará, during both the rainy and dry seasons. We compared simpler methods of ETo estimation to the FAO 56 Penman-Monteith method. For this purpose, meteorological data from Tracuateua, Bragança, Capitão Poço and Castanhal, provided by the National Institute of Meteorology (INMET), were used. The calibration of equations was performed through linear regression. The accuracy of different estimation methods was examined. The Turc, FAO 24 Blaney-Criddle and regression methods presented the best results for all statistical criteria; the Priestley-Taylor, Makkink and FAO 24 Radiation methods presented excellent results after calibration. The methods of Camargo and Hargreaves-Samani produced the worst results for all the criteria. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the study was to exploit the feasibility of thermoluminescent dosimeters (TLDs) in radiation therapy techniques in which high dose per fraction is involved. Methods: Dose--response of TLD-100 (LiF: Mg, Ti) was investigated in both 6-MV photon and 6-MeV electron beams. The element correction factor (ECF) generation method was applied to check the variability of the TLDs response. Two batches of 50 TLDs were divided into groups and exposed in the dose range 0 to 30 Gy. Regression analysis was performed with both linear and quadratic models. For each irradiation beam, the calibration curves were obtained in 3 dose range 0 to 8 Gy, 0 to 10 Gy, and 0 to 30 Gy. The best-fitting model was assessed by the Akaike Information Criterion test. Results: The ECF process resulted a useful tool to reduce the coefficients of variation from original values higher than 5% to about 3.5%, for all the batches exposed. The results confirm the linearity of dose--response curve below the dose level of 10 Gy for photon and electron beam and the supralinear trend above. Conclusion: The TLDs are suitable dosimeters for dose monitoring and verification in radiation treatment involving dose up to 30 Gy in a single fraction. [ABSTRACT FROM AUTHOR]

In this work, a semi-empirical equation in terms of γ -energy, and sample density is derived, proposed, benchmarked, and applied for the peak efficiency calibration of an HPGe detector with respect to an axial source-to-detector configuration. The samples are in the form of cone-shaped Marinelli beakers of different densities in the range 0.7–1.6 g/cm 3. The method employs the experimental measurements with the ANGLE-3 software calculations using the efficiency transfer method. The peak efficiency curve of an HPGe detector is calculated using the experimental measurements of point-like sources ( 133 Ba , 137 Cs , and 60 Co). The ANGLE-3 software is then used to calculate the peak efficiency curves for samples with different densities in the γ -energy range 81–1332 keV. The peak efficiency curves are then fitted to get the energy coefficient; in addition, a linear relationship is then constructed between the energy coefficients and sample densities to get the density coefficients, and the derived equation as well. The derived equations are benchmarked using the peak efficiency curves by ANGLE-3 software in comparison with that the equation results. The results are found to be in agreement with an average relative error of about 1.5%. In addition, the derived equations are applied to estimate the activity concentration of radionuclides present in 5 cone-shaped samples with different densities using experimental measurements. The activity results are found to be in agreement with the certified values with an average relative error of about 2%. The limitation of the proposed equations is also discussed with respect to different material densities and different chemical compositions and correction factors for material composition self-attenuation for various materials are also presented. • A semi-empirical equation for HPGe peak efficiency calibration is proposed • The equations were derived using the ANGLE software calculations. • They are validated, and applied using experimental measurements. • The derived equations are simple, accurate, and time efficient. [ABSTRACT FROM AUTHOR]

Low-cost air quality sensors measuring air quality at fine spatio-temporal resolutions, typically suffer from sensor drift and interference. Field calibration is typically performed at one location, while little is known about the spatial transferability of correction factors. We evaluated three calibration methods using a year of hourly nitrogen dioxide (NO 2) observations from low-cost sensors, collocated at two sites with a conventional monitor as reference: (1) an iterative Bayesian approach for daily estimation of the parameters in a multiple linear regression model, (2) a daily updated correction factor and (3) a correction factor updated only when concentrations are uniformly low. We compared the performance of the calibration methods in terms of temporal stability, spatial transferability, and sensor specificity. We documented drift within the 1-year period. The correction factor updated under uniformly low concentrations performed poorly. The iterative Bayesian approach and daily correction factor reduced the root mean squared error (RMSE) by 21–46% at the calibration locations, but did not reduce RMSE at the other location. By examining the posterior distributions of the regression coefficients, we found that the poor spatial transferability is consistent with different responses of individual sensors to environmental factors. We conclude that the spatial and temporal variability in the calibration parameters requires them to be updated regularly, including sensor-specific recalibrations. Image 1 • NO2 sensor calibration methods, accounting for drift and interference, were compared. • Calibration parameters were iteratively estimated using INLA. • Correction factors were updated daily and when concentrations were uniformly low. • Sensor differences cause spatio-temporal variability in the calibration parameters. • Calibrating one sensor is not enough; regular sensor-specific calibrations are needed. [ABSTRACT FROM AUTHOR]

An experimental study was conducted on the calibration method and measurement error for a plate thermometer (PT) that can replace the heat flux gauge (HFG), which is generally used to measure heat flux. A conical heater included in the cone calorimeter (ISO 5660-1) was used. It is well known that this device can easily control heat flux and has excellent measurement reproducibility. Heat flux values between 10 and 50 kW/m2 were considered and the heat flux calculated by PT was compared with the measurement result obtained using HFG. The major finding is that the gas temperature (Tg) required for the calculation of heat flux using the PT must be measured at the bottom of the sample and not in the vicinity of PT's surface. This resulted in a significantly reduced relative error of approximately 5.3 % based on HFG. It was also confirmed that the conduction correction factor (Kcond), which has the largest uncertainty in the calculation of the heat flux based on PT, was 8.6 W/m2·K on average and the final relative error was significantly reduced to 1.4 % based on HFG. It is expected that the measurement error of the PT can be further improved by utilizing more specific heat flux range settings in the calibration process of the PT using a conical heater included in the cone calorimeter (ISO 5660-1). [ABSTRACT FROM AUTHOR]

Following a nuclear incident, 131I monitoring is usually carried out by performing in vivo measurements of the retained activity in the thyroid. The measurement equipment needs to be calibrated in order to convert thyroid count rates into retained activity. This calibration relies on measurements or Monte Carlo computations using appropriate anthropomorphic model of the thyroid gland contaminated with a known activity of the radionuclide of interest. Several factors influence the calibration procedure, such as the geometry, the individual anatomical characteristics, and the presence of 131I in other organs and tissues of the body. In particular, given their age-dependent anatomical changes, appropriate values of detector efficiencies for children are necessary to reduce results uncertainties when children are involved. In this study, Monte Carlo simulations for several detectors and phantoms of different ages have been performed to investigate the variation of the detection efficiency with distance, age and thyroid volume. It was found that the counting efficiency varies linearly with the thyroid volume and inversely with the squared detector-phantom distance. Age-dependent correction factors to be applied to the adult calibration factor have been derived and can be used when calibration factors for children are not available. • Summary of Monte Carlo simulation in study in CAThyMARA project is presented. • Variation of detection efficiency for in vivo measurement of 131I with distance, age and thyroid volume have been studied. • Age-dependent correction factors to be applied to the adult calibration factor have been derived. • The contribution of extra-thyroidal radioiodine has been modelled as a function of elapsed time since intake. [ABSTRACT FROM AUTHOR]

A model describing the ORTEC GMX-30190-P coaxial n-type HPGe detector with a thin beryllium window was created. The absolute fullenergy peak efficiency calibration for measurements of activated ITER materials was performed in the gamma-energy range from 60 to 1836 keV using a semi-empirical approach employing Monte-Carlo-based efficiency transfer method. The validity of the model was shown by cross-checking against the experimental data obtained with a calibration standard of the same geometry. The additional correction factors for a self-absorption of gamma rays in different sample matrices were also calculated. [ABSTRACT FROM AUTHOR]

Purpose: We are developing a calibration methodology for full‐field digital mammography (FFDM). Calibration compensates for image acquisition technique influences on the pixel representation, ideally producing improved inter‐image breast density estimates. This approach relies on establishing references with rigid breast tissue‐equivalent phantoms (BTEs) and requires an accurate estimate of the compressed breast thickness because the system readout is nominal. There is also an attenuation mismatch between adipose breast tissue and the adipose BTE that was noted in our previous work. It is referred to as the "attenuation anomaly" and addressed in this report. The objectives are to evaluate methods to correct for the compressed breast thickness and compensate for the attenuation anomaly. Methods: Thickness correction surfaces were established with a deformable phantom (DP) using both image and physical measurements for three direct x‐ray conversion FFDM units. The Cumulative Sum serial quality control procedure was established to ensure the thickness correction measurements were stable over time by imaging and calibrating DPs biweekly in lieu of physical measurements. The attenuation anomaly was addressed by evaluating adipose image regions coupled with an optimization technique to adjust the adipose calibration data. We compared calibration consistency across matched left and right cranial caudal (CC) mammographic views (n = 199) with and without corrections using Bland–Altman plots. These plots were complemented by comparing the right and left breast calibrated average (μa) and population distribution mean (ma) with 95% confidence intervals and difference distribution variances with the F‐test for uncorrected and corrected data. Results: Thickness correction surfaces were well approximated as tilted planes and were dependent upon compression force. A correction was developed for the attenuation anomaly. All paddles (large and small paddles for all units) exhibited similar tilt as a function of force. Without correction, ma = 0.92 (−1.77, 3.62) was not significantly different from zero with many negative μa samples. The thickness correction produced a significant shift in the μa distribution in the positive direction with ma = 13.99 (11.17, 16.80) and reduced the difference distribution variance significantly (P < 0.0001). Applying both corrections in tandem gave ma = 22.83 (20.32, 25.34), representing another significant positive shift in comparison with the thickness correction in isolation. Thickness corrections were stable over approximately a 2‐year timeframe for all units. Conclusion: These correction techniques are valid approaches for addressing technical problems with calibration that relies on reference phantoms. The efficacy of the calibration methodology will require validation with clinical endpoints in future studies. [ABSTRACT FROM AUTHOR]

Highlights • Stability measurements of extractor vacuum gauge (EXG) for different gases. • Relative sensitivity of EXG. • Sensitivity and long-term stability measurements of QMS. Abstract In this study, the stability of an extractor gauge (EXG) was investigated through the determination of correction factors (CFs) over a pressure range 5 × 10−5 Pa to 9 × 10−3 Pa by using a Spinning Rotor Gauge (SRG) traceable to UME Static Expansion System, during 20 months and 15 months for N 2 and He, respectively. Percent and fractional changes in CFs were studied and sensitivities of EXG were also presented for Ar and CO 2. Direct comparison method was used for EXG stability measurements. Additionally, sensitivity measurements of Quadrupole Mass Spectrometer (QMS) were performed in the range of 1.0 × 10−6 Pa to 1.0 × 10−2 Pa at emission currents of 2 mA, 0.4 mA and 0.1 mA for He, N 2 and Ar. Long-term stabilities of QMS for N 2 and He were analyzed for about 2 years. EXG and SRG were used for QMS sensitivity measurements. The changes in CF of EXG remained within ±5% and ±6%, and fractional changes remained within about ±0.03 and ±0.05 for seven and five different measurement runs for N 2 and He, respectively. The change in CF of EXG based on the mean value of the relevant pressure point is 5.8% and 7.8% at 5 × 10−5 Pa, 5.3% and 5.9% at 9 × 10−3 Pa, and maximum CF changes relative to the first calibrations ranges from −1.7% to 2.4% and from −1.0% to 4.7% within the selected pressure range for N 2 and He, respectively. The changes of QMS sensitivity are strongly dependent to the electron current. Maximum changes of QMS sensitivities over a three month period are 44% and −35% for N 2 and He, respectively. This study was conducted in the frame of EMRP IND12 "Vacuum Metrology for Production Environments" project that was funded by the European Metrology Research Programme (EMRP). [ABSTRACT FROM AUTHOR]

Reverse iontophoresis (RI) is a promising technology in the field of continuous glucose monitoring (CGM), offering significant advantages such as finger-stick-free operation, wearability, and non-invasiveness. In the glucose extraction process based on RI, the pH of the interstitial fluid (ISF) is a critical factor that needs further investigation, as it directly influences the accuracy of transdermal glucose monitoring. In this study, a theoretical analysis was conducted to investigate the mechanism by which pH affects the glucose extraction flux. Modeling and numerical simulations performed at different pH conditions indicated that the zeta potential was significantly impacted by the pH, thereby altering the direction and flux of the glucose iontophoretic extraction. A screen-printed glucose biosensor integrated with RI extraction electrodes was developed for ISF extraction and glucose monitoring. The accuracy and stability of the ISF extraction and glucose detection device were demonstrated with extraction experiments using different subdermal glucose concentrations ranging from 0 to 20 mM. The extraction results for different ISF pH values exhibited that at 5 mM and 10 mM subcutaneous glucose, the extracted glucose concentration was increased by 0.08212 mM and 0.14639 mM for every 1 pH unit increase, respectively. Furthermore, the normalized results for 5 mM and 10 mM glucose demonstrated a linear correlation, indicating considerable potential for incorporating a pH correction factor in the blood glucose prediction model used to calibrate glucose monitoring. [Display omitted] [ABSTRACT FROM AUTHOR]

A new scheme for periodical technical inspection (PTI) of diesel-engine exhaust based on the measurement of particle number (PN) concentration was recently introduced in several European countries. PN concentration is measured directly at the tailpipe using portable particle counters known as PN-PTI. The technical specifications of these instruments are defined at a national level, and the type-examination and verification procedures differ considerably among European countries. In this study, we examined how the choice of test aerosol can affect the counting efficiency profile of the PN-PTI sensors, the majority of which are based on diffusion charging (DC). Carbonaceous aerosols were produced by combustion and spark discharge generators, sodium chloride (NaCl) particles were generated from aqueous solutions using several commercially available nebulizers and silver particles were produced by a silver particle generator. In most cases, the response of DC-based sensors depended strongly on the morphology of the test particles. Comparison with a Euro 3 diesel engine without a diesel particle filter (DPF) indicated that the combustion aerosols generated by combustion generators were the best proxy for soot emitted by diesel vehicle engines. On the contrary, the use of NaCl and spark discharge particles as test aerosols led in some cases to an over- or underestimation of the PN concentration by up to about a factor of two. Moreover, our results showed that the response of each type of DC-based sensors is individual and, as a result, it is impossible to determine a generally applicable factor to correct for the impact of the test aerosol properties. We recommend that the verification of PN-PTI instruments be preferably performed with soot particles produced by a combustion generator (identical or similar to the one used during the type-examination) in order to avoid corrections for the impact of the material on the response of the instruments. • Particle counters for the periodic technical inspection of diesel-vehicle exhaust respond differently to different aerosols. • Deviations in counting efficiency are observed with spark discharge and NaCl particles in the case of diffusion chargers. • Diffusion chargers respond differently to monodisperse and polydisperse aerosols. • No "universal" correction factor can be defined to account for artefacts related to the test aerosol properties. • Soot from combustion generators is recommended as test aerosol for both type-examination and verification procedures. [ABSTRACT FROM AUTHOR]

• Literature review of experimental calibration of thermal dissipation sap flow studies. • Granier coefficients vary depending on wood characteristics. • Correction parameter was positively associated with vessel area and stem diameter. Accurate estimate of transpiration is crucial to understanding global water and carbon cycles. The thermal dissipation (TD) method with Granier's equation, which is the most popular approach to measure whole-tree water use, requires species-specific calibration parameters to calculate transpiration. Calibrations require direct measurement of water uptake, often through gravimetric or potometric methods; therefore, it is often disregarded because of limited time and resources. It remains unclear which factor influences the variation of calibration parameters. In this study, we compiled published calibration experiments to elucidate the factors that could influence the variation in coefficients and attempted to predict the correction parameter. The results showed that: (1) only 14 % of the experiments provided accurate sap flux density estimates using the default parameter values in the Granier's equation, and sap flux was underestimated to varying degrees in 72% of the experiments; (2) the regression slope of TD-measured and the actual sap flow with the y-axis intercept set to zero (hereinafter referred to as " Slope") was significantly correlated to the mean vessel area (VA), i.e., species with larger VA consistently had higher Slope and greater bias. Stem diameter also had a positive influence on the Slope after accounting for covariation with the VA. Finally, a multiple linear regression model based on these two characteristics (VA and stem diameter) explained 89% of the variation of Slope. This study provides a simple calibration procedure for the users of TD-sensors with a linear correction model based on easily measurable vessel area and stem diameter. It may also provide a new development avenue for sensor manufacturers or others to improve the TD method to reduce its sensitivity to wood characteristics – or provide some "out-of-the-box" correction factors across a range of wood characteristics. [ABSTRACT FROM AUTHOR]