Data Treatment Method Research Articles

New method for data treating in polarization measurements

Precise formulae are presented for the expected value and the variance δξ of the random variable ξ corresponding to the spin asymmetry A. The equality = A and the finiteness of δξ give the base of the new method for data treatment which ability is illustrated by Monte Carlo calculations. The proposed method allows to find the asymmetry from experimental data without a detailed study of the detector efficiency as a function of kinematic variables. The systematic uncertainty due to the background contribution is evaluated with the aid of the formula for the expected value of the random variable η which generalizes ξ for the non-zero background contribution.

New approach to stress analysis based on grazing-incidence X-ray diffraction

A new development in the determination of residual stresses in thin surface layers and coatings is presented. The procedure, based on the grazing-incidence X-ray diffraction geometry (referred to here as the `g-sin2 ψ' geometry), enables non-destructive measurement at a chosen depth below the sample surface. The penetration depth of the X-ray radiation is well defined and does not change during the experiment. The method is particularly useful for the analysis of non-uniform stresses in near-surface layers. The g-sin2 ψ geometry was applied for measurements of the residual stresses in TiN coatings. Anisotropic diffraction elastic constants of textured material were used to determine the stress value from the measured lattice strains. A new method of data treatment enables reference-free measurements of residual stresses.

A missing data treatment for data mining applications in medical information systems.

To apply user-friendly, easily operated and accessible tools to handle missing data resulting from an auto-stored medical information system, these tools are applied to satisfy general users from different disciplines (i.e. statistics and machine-learning), followed by medical information system development. This study attempts to develop a new logic separation inference method applied to a database with a format like most real-world medical records containing many missing data and miscellaneous variables. It is expected that this method should have better performance than currently accessible methods. The newly developed logic separation inference method shows a classification power of 0.997 (elimination method is 1), which is better than the simple replacing method (replaced by mode shows 0.974). Both inference methods (mode and mean) have superior classification power to the simple replacing method. The missing data treatment processes introduced in this study can be completed on a MS Excel spreadsheet without any complicated calculation; therefore, they can satisfy general users. This new missing data treatment method is only applied up to 60% of the missing data (missing at random). However, when there is large amount of data, it is expected that this method also can be applied to a database missing more than 60%.

Measurements within unsteady cavitation

A current method used to characterize the phase distribution within gas (or vapor)/liquid two-phase flows consists of using local probes. Two sensors placed in series enable void fraction, velocity, and chord length measurements. The choice of the data treatment method depends strongly on the unsteady behavior of the flow: the higher the velocity fluctuations, the more complex and time consuming the data treatments. Three different methods have been developed to study various cavitating flow conditions. They have been applied to characterize two-phase flows within sheet cavities using a double optical probe.

Texture analysis of a muscovite-bearing quartzite: a comparison of some currently used techniques

Four well-established techniques were applied to determine the mineral textures of a muscovite-bearing quartzite: (1) directional measurements on an optical U-stage; (2) X-ray; (3) neutron; and (4) electron diffraction (EBSD). Techniques (1) and (4) are of the ‘single grain’ type and techniques (2) and (3) of the ‘statistical’ or ‘volume’ type. Experimental pole density diagrams were compared by means of the construction of pole figure differences (‘difference pole figures’), which led to the observation that EBSD- and U-stage derived pole figures agree well, even in detail. In contrast, pole figures derived from X-ray and neutron diffraction are clearly different from pole figures derived from the single grain techniques, visible as pronounced preferred orientation in the difference pole figures. Specific properties of the applied techniques may be responsible for the observed differences, such as (1) missing proportionality to the grain volume in the single grain methods, (2) the accessible sample volume, (3) erroneous data correction, or (4) statistical errors. Also the method of data treatment, which is basically different for the single grain and statistical methods, should be considered when pole figures are evaluated. Apart from purely economical constraints and availibility of equipment, the decision on the most suitable method for a texture determination should be based on the scientific goals and specific properties of particular techniques. Texture measurements of the statistical type are well suited for determination of bulk textures of rocks (e.g. as required for the calculation of anisotropic physical properties of rocks), whereas single grain measurements are advantageous for the investigation of local textures and texture forming mechanisms.

Measurement of gas jet flow velocities using laser-induced electrostrictive gratings

We used time-resolved light scattering of cw probe laser radiation from laser-induced electrostrictive gratings for the determination of flow velocities in air at room temperature. Some possibilities of the technique have been experimentally demonstrated with submerged planar air jets in atmosphere, both for accumulated and single-shot measurements. The range of investigated flow velocities was 5–200 m/s. The method of data treatment and of the estimate of the experimental parameters is described.

Contribution to residual-stress evaluation in high-stress-gradient zones by X-ray diffraction

The non-destructive X-ray diffraction method is usually employed to evaluate stress states at the near surface of materials. In specific zones with high-stress gradients parallel to the surface, like welding joins, areas affected by lasers, or ball-bearing raceways, the classical measurement method is not particularly well suited, as the irradiation spot covers regions of varying stress according to its size. This leads to inaccurate stress evaluations. A new X-ray diffraction measurement and data treatment method is therefore proposed. It is based on longitudinal step-by-step scanning in a fixed direction of the surface. As the acquired data results from the convolution of local diffraction peaks with the incident-beam intensity, an accurate model of the true two-dimensional intensity distribution inside the spot has been developed. Firstly, the true shape and size of the irradiation area is defined. The distribution of the intensity received by the sample surface is then computed. The true local strains and stresses along the scanning direction are finally determined from the acquired peaks using an optimization through a least-squares fitting by a nonlinear function.

An Hermite expansion method for EXAFS data treatment and its application to Fe K-edge spectra

A new Hermite expansion method has been developed for EXAFS data treatment. This transformation technique involves an expansion into a series of odd Hermite functions, which are eigenfunctions of the sine Fourier transform. In this communication, we report mainly the use of the method to filter iron K-edge X-ray absorption data. Unlike the other numerical Fourier techniques, the new method takes into consideration additional physical information on the experimental data, i.e. both the length of the interval of the measurements and an estimation of the length of the interval of significant structure changes in real space are parameters of the method. The method was validated with iron K-edge fluorescence spectra of magnetite and applied to iron exchanged ZSM-5 zeolite with low iron loadings (0.75 wt.%). We are able to show that, compared to the same data unfiltered or spectra Fourier filtered with a large Gaussian window, the noise level is strongly reduced and artefacts at higher distances disappear. The validity of the method was proved by applying it to magnetite (Fe3O4), where it is possible to fit the two Fe–O distances (octahedral and tetrahedral sites) known from X-ray diffraction. With the new method, these shells are statistically significant and are observed as individual contributions in the Fourier transforms. We also show that the new method, unlike conventional Fourier techniques, retains the statistical independence of the data.

Application of Weibull distribution analysis to the dielectric failure of multilayer ceramic capacitors

The Weibull distribution has been previously applied to the mechanical and dielectric failures of ceramics. In this paper, it is confirmed by experiment that this data treatment method is also valid for application in the dielectric failure of multilayer ceramic capacitors (MLCs) which have undergone screening. The Weibull modulus is found to be a useful parameter indicating the sharpness of the distribution of breakdown voltages and mechanical strength of MLCs. By Weibull analysis, the lately developed relaxor-based MLCs are found to compare favorably with traditional barium-titanate-based MLCs, implying that relaxor MLCs are more attractive than generally realised.

Biological Variation in the Degree of Polymerization of Cotton Lint Cellulose Produced in South Africa

The SEC-MALLS techniques, together with an alternative method for data treatment, are used to determine actual DP distributions of the cellulose of southern African Acala 1517/70 cotton lint. This alternative approach offers the possibility of exhaustive statistical analyses of acquired data, previously not possible. The results of these analyses show the influence of production area and year on variations in DP distributions of the cellulose of South African cotton lint.

Distribution of metals in soils and relationships among fractions by principal component analysis

A sequential extraction procedure (speciation procedure) was proposed with the aim of determining the distribution of Pb, Co, Ni, Cu, Zn, Mn, Fe, Cd and Cr among the different fractions of soil samples taken in three locations; two in rural areas and one in an industrial area. These results provided information about the main fractions where these metals were accumulated in the soils studied. Principal component analysis was used as a method for data treatment to establish general relationships among metal amounts accumulated in the different fractions and general soil properties, which were expected to govern the metal distribution pattern. On the basis of the results obtained from the position maps of variables and samples, the carbonate content was the soil property with the greatest number of statistically significant correlations with metal contents in fractions, so it can be considered as a relevant parameter in the distribution of some metals such as Pb, Ni, Zn and Cu in the soils.

Accuracy of the correction for a hydrocarbon contamination layer in routine quantitative XPS analysis of oxygen‐inert samples

AbstractA procedure for determination of the reduced thickness of the contamination layer for oxygen‐inert samples was implemented. The correction algorithm is valid for the reduced thickness of a contamination layer x ≥ 0.3 (x is expressed as the ratio of the layer thickness to the electron attenuation length in the contamination layer at energy 1 keV). It is shown that the linear background subtraction method traditionally used in XPS generally does not provide correct results. Application of an advanced experimental data treatment method with correction for the presence of a contamination layer to quantitative surface analysis of Al2O3, SiO2, GeO2, Fe2O3, NiO, CuO and NaF resulted in a decrease of the mean error of analysis from 27% using the elemental sensitivity factors approach to 5%.

Employing simulated data to illustrate an important cause of the 'steepling' effect in breath alcohol analysis.

The 'steepling' effect (large excursions in analytical data over time) is a debated issue in forensic breath alcohol analysis with various explanations being postulated. Simulated breath alcohol data was generated according to a hypothetical kinetic model where single random samples as well as means of duplicate random samples were plotted with respect to time at 0.2 hour intervals. In addition, the simulated data was compared when both two or more digit treatment was employed. Results showed the occurrence of significant noise or 'steepling' when single, two-digit breath alcohol samples were employed as compared to a four-digit mean computed from three-digit duplicates. The magnitude of variability was quantified by means of nonlinear regression resulting in the residual sum of squares (RSS) = 0.00202 for the single analysis and RSS = 0.00053 for the mean of duplicates. The method of data collection and treatment appears to contribute significantly to the 'steepling' phenomenon. Intuitively, replicate analyses reduce variability and allow for more accurate kinetic modelling employing breath alcohol analysis.

Dynamic mechanical analysis and its relationship to impact transitions

AbstractDetailed, instrumented impact tests were carried out between about − 100 and 60°C for flexible poly(vinyl chloride) (PVC), ethylene vinyl acetate (EVA), and polypropylene (PP) films. Secondary impact transitions in addition to the main transitions were detected for all three films, indicating that multiple impact transitions may be far more general in occurrence than commonly expected. Wide frequency (from 0.05 to 100 Hz) dynamic mechanical spectra of the same materials were also generated over similar temperature ranges. A new data treatment method was proposed whereby the material dissipation function was evaluated by summing the responses over broad frequency ranges of the loss modulus and the impulse spectrum. The dissipation function when plotted as a function of temperature was found to accurately (to within 3 to 5°C) predict the location of the main impact transitions for all three polymers. In addition, the existence and location of the secondary impact transitions for both PVC an PP were predicted. Both the functional form and the temperature match between the experiments and predictions strongly support the validity of the proposed method. However, some discrepancy remained in predicting the very low temperature (−65°C) impact transition for EVA.

A Detwisting Prominence Event and Its Computer Representation

Many active and short-lived dynamic structures in the solar atmosphere (such as sprays, surges and active prominences) are responsible for transportation of mass and energy into the solar corona, although the contribution of each event is not the same. At the same time, this kind of plasma ejections owe their existence to local magnetic fields. One of the above mentioned phenomena is eruptive prominence. According to Schmieder (1988), common characteristics of eruptive prominences are helical structures, the rotational motions and ‘twisting’ or ‘detwisting’ of the fine structural threads.In this paper, our aim is to show the evolution of a detwisting prominence event and to present to the readers a new data treatment method which can be used to study this kind of event more precisely and rapidly.

Static light scattering technique applied to pectin in dilute solution. Part II: The effects of clarification

The effects of purification/clarification by ultracentrifugation and/or membrane filtration were studied by light scattering, GPC plus off-line capillary viscometry and GLC sugar analysis using a high-methoxyl citrus pectin as model substance. The emphasis of light scattering measurements was put on analysing the angular dependence of the scattered light. For that reason the interpretation of the measured data involved the use of master curves in addition to Zimm or Guinier plots. The benefits and limitations of this method of data treatment for complex systems are discussed both in theory and practice. Due to the natural heterogeneity of pectins, purification or classification modified the original sample by removing the high molecular weight and dense tail, leaving a physically and chemically heterogeneous polysaccharide.

The maximum entropy spectral analysis on void fraction fluctuation of helium liquid-vapour two-phase flow

Study of the time-spacial fluctuation phenomenon of void fraction inhelium liquid- vapour two- phase flow is very important for understanding the transition mechanism of flow patterns, specially, in superconducting-magnet cooling system. In this paper, the void fraction wave has been studied by focusing the attention in experiment with the TSA (Time Series Analysis) method that is a very useful data treatment method for stochastic process. The results have clearly shown that with increasement of void fraction in helium two-phase flow the characteristic frequency in Maximum Entropy Marple Spectrum is moving into low frequency domain, which distinguishing feature can be used to be a new criterion for diagnosing flow patterns.

Molten Salt Regular Mixture Theory Applied to Ion Exchange Membranes

Exchange equilibria between a cation exchange membrane and an aqueous solution were studied experimentally and theoretically. By using thermodynamic components in terms of the Gibbs phase rule, and a suitable reference state, a convenient method for data treatment was obtained. Thermodynamic mixture properties were derived for one membrane with four pairs of monovalent cations. The results show that when the difference in cation size is small, the cation exchange membrane behaves nearly ideal. For larger differences, the membrane may be described as a regular mixture. Activity coefficients for membrane mixtures can be obtained easily for regular mixtures.

Studies on the critical temperature of thermal explosion for 3‐Nitro‐1,2,4‐triazol‐5‐one (NTO) and its salts

AbstractThe critical temperature of thermal explosion for 3‐nitro‐1,2,4‐triazol‐5‐one (NTO) and its ethylenediammonium salt (ENTO), potassium salt (KNTO), copper salt (CuNTO) and lead salt (PbNTO) were obtained using the stationary theory of thermal explosion, the calculation formula of estimating the critical temperature of thermal explosion under non‐isothermal DSC condition, and the determination method for the critical temperature of thermal explosion of small‐scale solid explosive and its data treatment method. The results of the four methods are agreeable to each other, whose differences are within 5%. The results indicate that the heat‐resistance ability of NTO and its salts and of the common explosives, cyclotetramethylenetetranitramine (HMX), cyclotrimethylenetrinitramine (RDX), pentaerythritoltetranitrate (PETN) and tetryl decreases in the order HMX > NTO > ENTO > KNTO > RDX > PETN > tetryl > PbNTO > CuNTO.

Small-angle neutron scattering from deuterated polystyrene in dioctyl phthalate solution under shear

Small-angle neutron scattering measurements were taken from high molecular weight (1.95 X lo6) deuterated polystyrene in dioctyl phthalate solution at low concentration (3 % weight fraction) under steady shear with rates ranging from the quiescent condition (0 s-l) to 1100 s-l at room temperature (22 OC). The scattered intensity increased drastically beyond a characteristic shear rate (+c = 57 9-1) similar to the increase following a temperature drop from the one-phase region (ambient temperature) to the two-phase region in this upper critical solution temperature system. The cloud point is estimated to be a few degrees lower than 14 OC which is the cloud point for protonated polystyrene in dioctyl phthalate at this molecular weight and concentration. On the basis of this analogy, the random-phase approximation (RPA) approach (the Zimm inverse scattering formula) was used along with a swollen radius of gyration in the Debye function to analyze the data and extract a statistical segment length b and a polymer-solvent interaction parameter xp. The segment length was seen to increase slightly, indicating a slight increase in chain volume beyond +c, while the interaction parameter showed a dramatic increase up to the 'spinodal value +* = 280 8-1 where the RPA breaks down, therefore giving nonreliable values. This data treatment method has no justification on physical grounds: it is merely a way to quantify our observations since specific models that could explain our data are not available at this time.