Data Correction Procedure Research Articles

Characterisation of Compressive Behaviour of Low-Carbon and Third Generation Advanced High Strength Steel Sheets with Freely Movable Anti-buckling Bars

Measuring the compressive behaviour of sheet materials is an important process for understanding the material behaviour and numerical simulation of metal forming. The application of side force on both surfaces of a specimen in the thickness direction is an effective way to prevent buckling when conducting compressive tests. However, the side effects of side forces (such as the biaxial stress state and non-uniform deformation) make it difficult to interpret the measured data and derive the intrinsic compressive behaviour. It is even more difficult for materials with tension–compression asymmetry such as steels that undergo transformation-induced plasticity. In this study, a novel design for a sheet compression tester was developed with freely movable anti-buckling bars on both sides of the specimen to prevent buckling during in-plane compressive loading. Tensile and compressive tests under side force were conducted for low-carbon steel using the digital image correlation method. The raw tensile and compressive stress–strain data of the low-carbon steel showed apparent flow stress asymmetry of tension and compression, originating from the biaxial and thickness effects. A finite element method-based data correction procedure was suggested and validated for the low-carbon steel. The third generation advanced high strength steels showed intrinsic tension–compression asymmetry at room temperature whereas the asymmetry was significantly reduced at 175 °C.

Enzymatically catalyzed CO2 -H2 O equilibration for oxygen isotope analyses of aqueous samples.

The classic CO2 -H2 O equilibration method is a very popular technique for the measurement of the oxygen isotope composition of aqueous samples in stable isotope geochemistry. This study examined whether enzymatically controlled CO2 -H2 O equilibration by carbonic anhydrase (CA) could reduce the time for oxygen isotope equilibrium between CO2 and H2 O at 25°C. Four types of aqueous samples containing CA were equilibrated with CO2 gases using a continuous flow isotope ratio mass spectrometer equipped with an automated gas sample collection device. We examined the effect of CA concentration in an aqueous sample, the influence of drying technique for the preparation of sample vials containing dried CA, the age of CA stock solution, and the ionic strength and the oxygen isotope composition of aqueous samples. CA rapidly catalyzed the oxygen isotope exchange between CO2 and H2 O and was unaffected by drying technique or stock solution age. Compared with aqueous samples with no CA or 0.2 μmolal CA, samples containing 4μmolal CA significantly reduced the CO2 -H2 O equilibration time for deionized water and artificial seawater (ionic strength = ~0.6) from ~19 h and ~23 h to ~0.30 h and ~0.77 h, respectively at 25°C. This enzymatically catalyzed CO2 -H2 O equilibration method is time-efficient, cost-effective, requires no additional data correction procedure, and can be used for most commercially available CO2 -H2 O equilibration devices without any modification.

Dynamic pressure probe response tests for robust measurements in periodic flows close to probe resonating frequency

A single-hole probe was designed to measure steady and periodic flows with high fluctuation amplitudes and with minimal flow intrusion. Because of its high aspect ratio, estimations showed that the probe resonates at a frequency two orders of magnitude lower than the fast response sensor cut-off frequencies. The high fluctuation amplitudes cause a non-linear behavior of the probe and available models are neither adequate for a quantitative estimation of the resonating frequencies nor for predicting the system damping. Instead, a non-linear data correction procedure based on individual transfer functions defined for each harmonic contribution is introduced for pneumatic probes that allows to extend their operating range beyond the resonating frequencies and linear dynamics. This data correction procedure was assessed on a miniature single-hole probe of 0.35 mm inner diameter which was designed to measure flow speed and direction. For the reliable use of such a probe in periodic flows, its frequency response was reproduced with a siren disk, which allows exciting the probe up to 10 kHz with peak-to-peak amplitudes ranging between 20%–170% of the absolute mean pressure. The effect of the probe interior design on the phase lag and amplitude distortion in periodic flow measurements was investigated on probes with similar inner diameters and different lengths or similar aspect ratios (L/D) and different total interior volumes. The results suggest that while the tube length consistently sets the resonance frequency, the internal total volume affects the non-linear dynamic response in terms of varying gain functions. A detailed analysis of the introduced calibration methodology shows that the goodness of the reconstructed data compared to the reference data is above 75% for fundamental frequencies up to twice the probe resonance frequency. The results clearly suggest that the introduced procedure is adequate to capture non-linear pneumatic probe dynamics and to reproduce time-resolved data far above probe resonant frequency.

Natural uncertainty of spatial average aquifer recharge through atmospheric chloride mass balance in continental Spain

In a previous paper, the atmospheric chloride mass balance (CMB) method for spatial average diffuse aquifer recharge by rainfall (R‾) in large and varied territories was evaluated. Continental Spain was chosen to show the reliability of this application. Two main sources of uncertainty (measured by the coefficient of variation, CV) affecting R‾, induced by the inherent natural variability of the variables (CVR) and from mapping (CVRK), were separated. While CVRK may be decreased with better data coverage, the part of CVR inferred by the variable length of yearly data series can be corrected by comparing them to existing long series. With the same data sets and methods as in a previous paper, a data-correction procedure to improve R‾ and CVR is presented. The critical balance period (N) to reach comparable steady (long-term) CMB averages and CV values (CVs) was defined. The correction considered the timing of short series to incorporate the yearly data oscillating trend from longer series, additional trends deduced from longer series having incomplete N-year cycles, and changing stationary parameters over space from several long series. In continental Spain, N = 10 years. This period coincides with the decadal global climatic cycles acting on the Iberian Peninsula. Corrected CMB averages and CVs were regionalized by ordinary kriging using the same 10 km × 10 km 4976-nodes grid used for mapping the original CMB components. Nodal R‾ values varied from 17 to 715 mm year–1, 90% ranging from 35 to 300 mm year–1. Data correction did not significantly change averages; corrected average R‾ was 2% higher. However, the CVs changed conspicuously. The average CVR was 0.29, more than twice the original 0.13. This more realistic estimation of CVs avoids the illusory precision obtained when the short series correspond to small change periods. The average CVRK was 0.09, similar to the original 0.07. The improvement is shown by the CV of CVR and CVRK, which notably decreased below 0.1, even when their absolute values increased.

Improving Communication-specific Coping after Traumatic Brain Injury: Evaluation of a New Treatment using Single-case Experimental Design

Background and aims: Impaired communication is a well-documented and enduring consequence of traumatic brain injury (TBI). As a result of this impairment, people with TBI frequently experience communication breakdown and associated stress. Typically, we use communication-specific coping strategies in situations characterised by communication breakdown. Productive strategies enhance message transfer; non-productive strategies do little to resolve problems and frequently result in negative social interaction. This research aimed to evaluate the effectiveness of a new treatment, Communication-specific Coping Intervention (CommCope-I), which specifically targets coping in the context of communication breakdown.Method: Single-case experimental design (A–B–A with follow-up using multiple probes) across two participants was used. Participants were Samantha, a 30-year-old woman who had sustained severe TBI 8 years previously, and Thomas, a 34-year-old man who had sustained severe TBI when he was 29 years old. CommCope-I is a 6-week programme which targets personally relevant productive coping strategies identified collaboratively with the client. Productive coping scripts are developed and practised through a series of graded scenarios that are evaluated with the aid of video recording.Results: Percentage of non-overlapping corrected data (PNCD) was used to analyse the results. PNCD involves a data-correction procedure to remove baseline trend from the data series prior to calculating the change produced as a result of intervention. A large treatment effect was demonstrated in both participants (PNCD: end of treatment Samantha = 100%, Thomas = 100%, 3-month follow-up Samantha = 100%, Thomas = 100%). These results are consistent with highly effective treatment.Conclusions: This study provides sound phase-1 evidence for the effectiveness of CommCope-I.

Density-driven structural transformations in network forming glasses: a high-pressure neutron diffraction study of GeO2 glass up to 17.5 GPa

The structure of GeO2 glass was investigated at pressures up to 17.5(5) GPa using in situ time-of-flight neutron diffraction with a Paris–Edinburgh press employing sintered diamond anvils. A new methodology and data correction procedure were developed, enabling a reliable measurement of structure factors that are largely free from diamond Bragg peaks. Calibration curves, which are important for neutron diffraction work on disordered materials, were constructed for pressure as a function of applied load for both single and double toroid anvil geometries. The diffraction data are compared to new molecular-dynamics simulations made using transferrable interaction potentials that include dipole-polarization effects. The results, when taken together with those from other experimental methods, are consistent with four densification mechanisms. The first, at pressures up to ≃ 5 GPa, is associated with a reorganization of GeO4 units. The second, extending over the range from ≃ 5 to 10 GPa, corresponds to a regime where GeO4 units are replaced predominantly by GeO5 units. In the third, as the pressure increases beyond ∼10 GPa, appreciable concentrations of GeO6 units begin to form and there is a decrease in the rate of change of the intermediate-range order as measured by the pressure dependence of the position of the first sharp diffraction peak. In the fourth, at about 30 GPa, the transformation to a predominantly octahedral glass is achieved and further densification proceeds via compression of the Ge–O bonds. The observed changes in the measured diffraction patterns for GeO2 occur at similar dimensionless number densities to those found for SiO2, indicating similar densification mechanisms for both glasses. This implies a regime from about 15 to 24 GPa where SiO4 units are replaced predominantly by SiO5 units, and a regime beyond ∼24 GPa where appreciable concentrations of SiO6 units begin to form.

Percentage of nonoverlapping corrected data

In the present study, we proposed a modification in one of the most frequently applied effect-size procedures in single-case data analysis: the percentage of nonoverlapping data. In contrast with other techniques, the calculus and interpretation of this procedure are straightforward and can be easily complemented by visual inspection of the graphed data. Although the percentage of nonoverlapping data has been found to perform reasonably well in N = 1 data, the magnitude of effect estimates that it yields can be distorted by trend and autocorrelation. Therefore, the data-correction procedure focuses on removing the baseline trend from data prior to estimating the change produced in the behavior as a result of intervention. A simulation study was carried out in order to compare the original and the modified procedures in several experimental conditions. The results suggest that the new proposal is unaffected by trend and autocorrelation and that it can be used in case of unstable baselines and sequentially related measurements.

Optimization of experimental procedure and statistical data treatment for kinetics of ethylene hydrogenation on a copper-magnesia catalyst

This study is an example of practical application of kinetic data treatment for simultaneous model discrimination and parameter estimation. The study is applied to the hydrogenation of ethylene on a copper-magnesia catalyst and brings a deepened analysis about the experimental strategy by comparing several alternative strategies using a priori and sequential experimental designs. The best model corresponds to a Langmuir–Hinshelwood mechanism with non-competing adsorption of hydrogen and ethylene and where the rate-determining step is either the addition of molecularly adsorbed hydrogen or the addition of the second atom of hydrogen adsorbed dissociatively. Furthermore, the important question of knowing in practice how many designs and how many measurements per design are actually necessary to determine accurate kinetic and physico-chemical parameters, is addressed. A data correction procedure is also presented that takes catalyst deactivation into account.

Measurement of Broadband Diffuse Solar Irradiance Using Current Commercial Instrumentation with a Correction for Thermal Offset Errors

Abstract Diffuse-sky solar irradiance is an important quantity for radiation budget research, particularly as it relates to climate. Diffuse irradiance is one component of the total downwelling solar irradiance and contains information on the amount of downward-scattered, as opposed to directly transmitted, solar radiation. Additionally, the diffuse component is often required when calibrating total irradiance radiometers. A variety of pyranometers are commonly used to measure solar diffuse irradiance. An examination of some instruments for measuring diffuse irradiance using solar tracking shade disks is presented, along with an evaluation of the achieved accuracy. A data correction procedure that is intended to account for the offset caused by thermal IR exchange between the detector and filter domes in certain common diffuse pyranometers is developed and validated. The correction factor is derived from outputs of a collocated pyrgeometer that measures atmospheric infrared irradiance.

Three-way monolithic converter: Simulations versus experiments

A simple one-dimensional model for a three-way catalytic converter is briefly described and solved. It accounts for the HC(hydrocarbons) CO oxidation and NO reduction reactions. The engine experiments include temperature, air/fuel ratio and gas flow step changes and pulses. In spite of the numerous simplifying assumptions, the agreement is good. The discrepancies are essentially attributed to the accuracy limit of the time-resolved input data, to the extreme sensitivity of the reactions about light-off temperature, to a possible internal diffusion limitation at high temperature, and to some transient state catalytic process which was neglected in the model. Thermal shocks only validate the thermal description of the model. Slow temperature excursions about light-off, and changes of the air/fuel ratio are more conclusive for the chemical description. The study of high-frequency signals requires an efficient data correction procedure and probably to include a description of oxygen storage into the model.

Structural Study of Liquid Ethylbromide Using Differential Anomalous X‐ray Scattering

AbstractSynchrotron radiation was used for a differential anomalous X‐ray scattering (DAS) study of liquid ethylbromide (C2H5Br). Two diffraction experiments were carried out at photon energies of 12500 and 13464 eV. The dispersion corrections were determined from photoabsorption coefficients obtained from an absorption experiment. After an elaborate and involved data evaluation and correction procedure a differential structure factor was obtained. The peak assignation in the differential atom pair correlation function (DAPCF) was verified by comparison with a theoretical intramolecular distribution function calculated from well known data of the intramolecular geometry of ethylbromide. In addition, a peak at 4.1 Å is found in the DAPCF, which may be assigned to an intermolecular Br—Br atom pair suggesting a strong dispersion interaction.

A correction procedure for the asymmetry of differential pressure transducers in respiratory impedance measurements.

The usual setup for measuring respiratory input impedance requires a differential pressure transducer attached to a pneumotachograph. As, up to now, no data correction procedure has been devised to account for transducer asymmetry, a highly symmetrical transducer is required to obtain reliable impedance data. In this communication, a general model for the measuring system is presented. Its main feature is that differential pressure transducers are modeled as two input-one output systems. From the theoretical model, we defined a dynamic calibration and data correction procedure. This was tested using highly asymmetrical transducers (common-mode rejection ratio between 45 and 27 dB) to measure the impedance of two respiratory analogs. The latter were linear resistance (R), inertance (I), compliance (C) series models simulating a normal subject (R = 3.47 hPa.s.l-1, I = 1.45 Pa.s2.l-1, C = 18.6 ml.hPa-1) and an obstructive patient (R = 11.15 hPa.s.l-1, I = 1.28 Pa.s2.l-1, C = 18.5 ml.hPa-1). Results obtained applying the devised procedure (errors in R, I, and C always less than 4 percent) show that respiratory input impedance can be adequately measured if data are corrected for transducer asymmetry.

Effects of intense ultraviolet radiation on electrostatic energy analyzers

Intense ultraviolet radiation from the plasma poses a significant problem for the implementation of heavy ion beam probe diagnostic systems on fusion-oriented confinement devices. The radiation enters the electrostatic energy analyzer used to detect secondary ions, resulting in both a distortion of the electric field inside the analyzer and noise generation in the detector channels. Data-acquisition procedures and mechanical design techniques have been developed to significantly reduce these effects. We have also been successful in modeling the electric field distortion and have developed a data correction procedure based on this model. Methods for approaching the problems anticipated in future devices are also suggested.