Residual Stresses from Incremental Hole Drilling Using Directly Deposited Thin Film Strain Gauges

Background Commonly, polymer foil-based strain gauges are used for the incremental hole drilling method to obtain residual stress depth profiles. These polymer foil-based strain gauges are prone to errors due to application by glue. For example zero depth setting is thus often erroneous due to necessary removal of polymer foil and glue. This is resulting in wrong use of the calibration coefficients and depth resolution and thus leading to wrong calculations of the obtained residual stress depth profiles. Additionally common polymer foil-based sensors are limited in their application regarding e.g. exposure to high temperatures. Objective This paper aims at a first step into the qualification of directly deposited thin film strain gauges for use with the incremental hole drilling method. With the directly deposited sensors, uncertainties regarding the determination of calibration coefficients and zero depth setting due to the absence of glue can be reduced to a minimum. Additionally, new areas of interest such as the investigation of thermally sprayed metallic layers can be addressed by the sensors due to their higher temperature resilience and their component inherent minimal thickness. Methods For the first time, different layouts of directly deposited thin film strain gauges for residual stress measurements were manufactured on a stainless steel specimen. Strain measurements during incremental hole drilling using a bespoke hole drilling device were conducted. Residual stress depth profiles were calculated using the Integral method of the ASTM E837 standard. Afterwards, strain measurements with conventional polymer foil-based strain gauges during incremental hole drilling were conducted and residual stress depth profiles were calculated accordingly. Finally the obtained profiles were compared regarding characteristic values. Results The residual stress depth profiles obtained from directly deposited strain gauges generally match the ones obtained from conventional polymer foil based strain gauges. With the novel strain gauges, zero depth setting is simplified due to the absence of glue and polymer foil. With the direct deposition, a wide variety of rosette designs is possible, enabling a more detailed evaluation of the strain field around the drilled hole. Conclusions The comparative analysis of the obtained residual stress depth profiles shows the general feasibility of directly deposited strain gauges for residual stress measurements. Detailed investigations on uncertainty sources are still necessary.

Calibration of Automatic Sun Photometer with Temperature Correction in Field Environment

Aerosol optical depth (AOD) is an important atmospheric correction parameter in remote sensing. In order to obtain AOD accurately, the surface-based automatic sun photometer needs to carry out calibration regularly. The normally used Langley method can be effective only when the AOD and the calibration coefficients of the instrument remain unchanged throughout the day. However, when observing the AOD with CE318 sun photometer in field environment, it was found that the AOD of silicon (Si) detector at 1020 nm and indium gallium arsenide (InGaAs) detector at 1639 nm was strongly influenced by temperature due to the large temperature difference at the Dunhuang site. Based on the corresponding relationship between AOD and wavelength, the model of the calibration coefficients varying with temperature was established by nonlinear regression method in field environment. By comparing the AOD before and after temperature correction with the theoretical one, the ratio of data with relative error (RE) less than 5% increased from 0.195 and 0.14 to 0.894 and 0.355, respectively. By this method, calibration can be carried out without the limit of constant AOD. In addition, it is simpler, more convenient, and less costly to perform temperature correction in a field environment than in a laboratory.

Attestation of conformity of particulate matter measurements (HIVATO) 2019–2020

The National Reference Laboratory for Air Quality (NRL) ensures the high quality of air quality measurements in Finland by organising audits and intercomparison campaigns. In this project, the conformity of the particulate matter measurements was evaluated with a particular focus on the measurement used for calculating the average exposure index (AEI) of Finland. The representativity and applicability of the AEI measurements made at the Kallio station in Helsinki were evaluated. It was noticed that the results of the Kallio measurement represent well the average fine particle (PM2.5) concentrations and the yearly based trend of fine particles in Finland. In addition, the yearly average concentrations of fine particles have been smaller than the AEI limit value of 8.5 µg/m3, at all individual urban background stations in Finland since year 2015. The measurement results made with the PM monitor used for AEI measurement, i.e. TEOM 1405 analyser at the Kallio station, were compared to the results from the reference method that follows the standard SFS-EN 12341:2014. It was noticed that the uncertainty requirement of 25% was reached and therefore the quality of the measurement is sufficient to use it for the calculation of AEI. However, the fine particle concentrations were generally very low and therefore the requirements given in the standard SFS-EN 16450:2017 for an intercomparison against the reference method were not perfectly fulfilled. This report presents also results from intercomparison measurements made for automated continuous measurement systems (AMS). At the Virolahti station and at the Mäkelänkatu station in Helsinki, PM10 and PM2.5 measurements were compared. In Kuopio and in Lahti, intercomparison measurements were made for PM2.5 only. Based on the results from these intercomparisons, the calibration coefficients both for PM10 and PM2.5 were defined for the first time in Finland for a FIDAS 200 analyser that is a new PM monitor in the Finnish market. It was concluded that FIDAS 200 analysers can be used for the PM measurements in Finland when the calibration coefficients are applied for the data; however, one must note that the presented calibration coefficients do not fulfil the requirements given for the demonstration of equivalence (DoE). Nevertheless, these coefficients are recommended to be used until the official coefficients will be delivered from the next DoE campaign. Two AMS (SHARP 5030 and TEOM 1405) were compared to the reference method for the measurements of PM10 and PM2,5 in Virolahti and in Helsinki, respectively. It was revealed that the calibration coefficients based on the DoE in Kuopio (2014–2015) do not always fit ideally at different locations and seasons due to differences in the environmental characteristics of the measurement sites. Therefore, NRL recommends that DoE should be organised every five years and in between the DoE’s so called ongoing-intercomparison measurements should be carried out continuously. In the ongoing-intercomparison, suitability of the calibration coefficients from DoE will be verified in different locations with varying environmental characteristics. The ongoing-intercomparison campaigns should take place at one site from a half a year to one year and after that, the campaign should continue at a different location similarly. This would ensure that the influence of seasonal differences to the suitability of coefficients will be verified at each measurement site.

The NMIJ air kerma primary standard for high energy X-ray beams in 300-450 kV

Accurate radiation dosimetry is required for radiation protection in various environments. Therefore, dosemeters and dose-rate meters must be calibrated in standard radiation fields. The National Metrology Institute of Japan (NMIJ) expands the energy range of X-ray reference field measurement up to 450 kV using a cylindrical graphite-walled cavity ionization chamber. Departure from the condition of the Spencer-Attix cavity theory was evaluated by comparing the measurement results obtained using the cavity ionization and the free-air ionization chambers, which are used as the primary standard up to a tube voltage of 250 kV. The calibration coefficients found using the spherical ionization chamber were in good agreement with those obtained by the free-air ionization chamber within relative standard uncertainties (k = 1) for N-200 and N-250 X-ray fields. Consistent calibration coefficients were obtained in the energy range 300–450 kV.

The In-orbit Performance of SEVIRI From Observations of Mercury and Venus

<p>We investigated various aspects of the in-orbit performance of SEVIRI on Meteosat-10 (launch: 05 Jul 2012) and -11 (launch: 15 Jul 2015) with images, where Mercury or Venus appeared in a corner. These objects are of similar or smaller size than the instantaneous field of view, and therefore they are well suited for checks of geometric requirements. From comparing the position of Venus in different channels we conclude that the North-South distance between the two focal planes is shorter than the nominal value by 0.66 km at SSP (Sub-Satellite Point) with Meteosat-10 and longer by 1.44 km at SSP with Meteosat-11. The tilt of the detector array against the equator is less than 0.0037° for SEVIRI on Metosat-10. The sampling with narrow channels is 3.0016 km, with a one-sigma uncertainty of 30 cm at sub-satellite point. The tests we carried out to check the geometric performance of the instrument confirmed that SEVIRI is compliant with the requirements. The Point Spread Function as determined from the image of a planet agrees well with the expectations based on its combination with the finite impulse response. Finally we determined the stability of the calibration coefficients from the counts obtained on the planetary targets and found the reproducibility of the measurements of planetary fluxes similar to those of vicarious calibration targets. Hence planets are a promising alternative to established methods of in-flight characterisation and validation of imagers.</p>

The In-orbit Performance of SEVIRI From Observations of Mercury and Venus

<p>We investigated various aspects of the in-orbit performance of SEVIRI on Meteosat-10 (launch: 05 Jul 2012) and -11 (launch: 15 Jul 2015) with images, where Mercury or Venus appeared in a corner. These objects are of similar or smaller size than the instantaneous field of view, and therefore they are well suited for checks of geometric requirements. From comparing the position of Venus in different channels we conclude that the North-South distance between the two focal planes is shorter than the nominal value by 0.66 km at SSP (Sub-Satellite Point) with Meteosat-10 and longer by 1.44 km at SSP with Meteosat-11. The tilt of the detector array against the equator is less than 0.0037° for SEVIRI on Metosat-10. The sampling with narrow channels is 3.0016 km, with a one-sigma uncertainty of 30 cm at sub-satellite point. The tests we carried out to check the geometric performance of the instrument confirmed that SEVIRI is compliant with the requirements. The Point Spread Function as determined from the image of a planet agrees well with the expectations based on its combination with the finite impulse response. Finally we determined the stability of the calibration coefficients from the counts obtained on the planetary targets and found the reproducibility of the measurements of planetary fluxes similar to those of vicarious calibration targets. Hence planets are a promising alternative to established methods of in-flight characterisation and validation of imagers.</p>

Calibrations coefficients for determination of concentrations of vacancy-oxygen-related complexes and oxygen dimer in silicon by means of infrared absorption spectroscopy

Vacancy-oxygen complexes VnOm (n, m ≥ 1) in crystalline silicon are nucleation centers for oxygen precipitates, which are widely used as internal getters in modern technologies of production of silicon-based electronic devices and integrated circuits. For the controllable formation of oxygen precipitates in Si crystals in the technology processes the methods of determination of concentrations of the VnOm complexes are required. The aim of the present work was to find values of the calibration coefficients for determination of concentrations of the VnOm defects in Si from intensities of infrared (IR) absorption bands associated with the local vibrational modes (LVM) of these complexes. A combined electrical (Hall effect) and optical (IR absorption) study of vacancy-oxygen defects in identical silicon crystals irradiated with 6 MeV electrons was carried out. Based on the analysis of the data obtained, the values of the calibration coefficient for the determination of concentration of the vacancy-oxygen (VO) complex in silicon by the infrared absorption method were established: for measurements at room temperature (RT) – NVO = 8.5 · 1016 · αVO-RT cm–3, in the case of low-temperature (LT, Т ≡ 10 K) measurements – NVO = 3.5 · 1016 · αVO-LT cm–3, where αVO-RT(LT) are absorption coefficients in maxima of the LVM bands due to the VO complex in the spectra measured at corresponding temperatures. Calibration coefficients for the determination of concentrations of other VnOm (VO2, VO3, VO4, V2O and V3O) complexes and the oxygen dimer (O2) from an analysis of infrared absorption spectra measured at room temperature have been also determined.

CALIBRATION COEFFICIENTS OF CONNECTION BETWEEN THE LANGMUIR ADSORPTION EQUATION AND V.N. OPARINA’S KINEMATIC EXPRESSION FOR PENDULUM-TYPE WAVES ACCORDING TO LOCAL MEASUREMENTS AT THE COAL DEPOSITS OF KUZBASS

The article shows that at present there are experimental and theoretical prerequisites for establishing formalized relationships between deformation-wave and physicochemical processes occurring in real multiphase rock massifs. The calibration coefficients of the relationship in the correspondence operator between the adsorption equation and the kinematic expression for pendulum waves were established, verified in comparison with the available measurements in laboratory and field experiments for coals of the entire metamorphic series: quantitative values of the physicochemical invariant were determined for coals of different stages of metamorphism and structural parameter of the geomedium, as well as the velocity of propagation of a longitudinal wave in geoblocks-carriers of pendulum waves and translational movement of "colliding" geoblocks for different stages of metamorphism. It is shown that the values of the obtained dispersion allow one to take into account all the variety of the main stages of metamorphism of Kuzbass coal deposits in the theory and forecast of outburst hazard, i.e. take into account the real qualities of coal seams.