Fitting Analysis Method Research Articles

Mapping hydrothermal altered mineral deposits using Landsat 7 ETM+ image in and around Kuju volcano, Kyushu, Japan

To evaluate the conventional methods for mapping hydrothermal altered deposits by using Landsat 7 ETM+ image in and around Kuju volcano is the prime target of our study. The Kuju volcano is a mountainous composite which consists of hornblende-andesite lava domes and associated lava flows. We used the colour composite, band ratio, principal component analysis, least square fitting and reference spectra analysis methods. The colour composite and band ratio methods showed very clearly the hydrothermal altered deposits of clay minerals, iron oxides and ferric oxides around the fumaroles. The principal component analysis using the Crosta technique also enabled us to represent undoubtedly the altered hydroxyl and iron-oxide mineral deposits of this region concentrating around the fumaroles. Least square fitting method illustrated the goethite, hematite and clay alteration region. Finally the target detection method for reference spectral analysis by using ENVI 4.3 detected the representative hydrothermal altered minerals around Kuju volcano fumaroles area. Therefore, all the methods showed high efficiency for mapping hydrothermal altered deposits especially iron-oxide minerals such as hematite, goethite and jarosite, which are alteration products of hydrothermal sulfides around the fumaroles.

Distributed disciplines of stress field near interface crack tip of double dissimilar materials and experiments' verification

In this paper, isochromatic of interface crack tip in orthotropic bi-materials can be observed by photo-elastic coating. The mechanics parameters as well as other parameters are derived. The testing value of mixed stress intensity factors is obtained with photo-elastic equation by using curve fitting and regression analysis method. Compared with theoretical results, the theoretical formulas for interface crack tip in orthotropic bi-materials are verified. The distribution of stress field is observed.

Threshold Regression Forecast Model for Dam Safety Monitoring and its Application

Affected by both of the internal and external factors during work process, the dam monitoring effect variable often generates complex cycles such as jumps, compendium, and re-jumps, which shows a high degree of non-linearity that brings a lot of trouble in the establishment of regular dam safety monitoring forecast model. Drawing on the threshold thought of the threshold autoregressive model, the threshold factor and the threshold value are introduced in the conventional regression model. By making use of the suggested best fitting correlation analysis method to determine the threshold factor and the threshold value, the threshold regression model is established. Application example shows that the method for dam safety monitoring forecast can obtain satisfactory results.

Image and pattern analysis for the determination of the method of drawing celebrated thera wall-paintings circa 1650 B.C.

In this article, an integrated conjecture about the method of drawing of monumental prehistoric wall-paintings is presented and supported. Specifically, the article deals with paintings that initially decorated the internal walls of the highest floor of a building, called “Xeste 3”, at Akrotiri of the Greek island of Thera circa. 1650 B.C. It is argued that these wall-paintings could had been drawn while the brush was guided by an apparatus, which corresponds to advanced for the era of geometric prototypes with impressive precision. A set of assumptions concerning the actions the artists might have taken in order to create the spiral themes is stated and supported. These assumptions refer to the existence of a draft plan, the sequence of brush strokes, the placement of the brush on the wall, as well as the possible form of the apparatus. These conjectures are evaluated and tested by means of curve fitting and image analysis methods developed by the authors. The results indicate that all drawn contour parts optimally fit along a single prototype linear spiral with fitting error of less than 0.4mm, supporting existence of a very advanced culture for the era of geometric guide. It is statistically rejected that this guide could have the form of a stamp. Moreover, there is strong evidence that the painter might have used a draft plan of the spiral themes to prepare the final drawing and that the linear spiral guide has been used by alternating its placements in order to form the internal and external spiral contour.

Kinetics and equilibrium studies for the removal of cadmium ions from aqueous solutions using Duolite ES 467 resin

Kinetic and equilibrium studies were conducted with cation exchange resin (Duolite ES 467) to investigate the effectiveness of removal of cadmium ions from aqueous solutions in a batch mode. The effect of various parameters was studied, such as contact time, agitation speed, sorbent mass, sorbate concentration, pH, competitive ion and temperature. The kinetic data were analyzed by finding their fitness to the well-known Lagergren and pseudo-second-order models using linear and non-linear curve fitting methods. Equilibrium isotherms generated were tested by applying Langmuir and Freundlich isotherm models using both linear and non-linear methods. The optimum contact time and agitation speed were found to be 60 min and 600 rpm, respectively. The presence of sodium chloride ions in solution drastically reduced the cadmium uptake. On the other hand, higher pH and temperature enhanced sorption. The non-linear curve fitting analysis method was found to fit the data better than the linear method. Similarly the Langmuir isotherm model has an edge over the Freundlich model. The calculated thermodynamic parameters such as ΔG 0, ΔH 0 and ΔS 0 indicate the effectiveness of Duolite ES 467 resin to remove cadmium from solution.

Modeling of ultrasonic degradation of non-volatile organic compounds by Langmuir-type kinetics

Sonochemical degradation of phenol (Ph), 4-isopropylphenol (4-IPP) and Rhodamine B (RhB) in aqueous solutions was investigated for a large range of initial concentrations in order to analyze the reaction kinetics. The initial rates of substrate degradation and H 2O 2 formation as a function of initial concentrations were determined. The obtained results show that the degradation rate increases with increasing initial substrate concentration up to a plateau and that the sonolytic destruction occurs mainly through reactions with hydroxyl radicals in the interfacial region of cavitation bubbles. The rate of H 2O 2 formation decreases with increasing substrate concentration and reaches a minimum, followed by almost constant production rate for higher substrate concentrations. Sonolytic degradation data were analyzed by the models of Okitsu et al. [K. Okitsu, K. Iwasaki, Y. Yobiko, H. Bandow, R. Nishimura, Y. Maeda, Sonochemical degradation of azo dyes in aqueous solution: a new heterogeneous kinetics model taking into account the local concentration OH radicals and azo dyes, Ultrason. Sonochem. 12 (2005) 255–262.] and Seprone et al. [N. Serpone, R. Terzian, H. Hidaka, E. Pelizzetti, Ultrasonic induced dehalogenation and oxidation of 2-, 3-, and 4-chlorophenol in air-equilibrated aqueous media. Similarities with irradiated semiconductor particulates, J. Phys. Chem. 98 (1994) 2634–2640.] developed on the basis of a Langmuir-type mechanism. The five linearized forms of the Okitsu et al.’s equation as well as the non-linear curve fitting analysis method were discussed. Results show that it is not appropriate to use the coefficient of determination of the linear regression method for comparing the best-fitting. Among the five linear expressions of the Okitsu et al.’s kinetic model, form-2 expression very well represent the degradation data for Ph and 4-IPP. Non-linear curve fitting analysis method was found to be the more appropriate method to determine the model parameters. An excellent representation of the experimental results of sonolytic destruction of RhB was obtained using the Serpone et al.’s model. The Serpone et al.’s model gives a worse fit for the sonolytic degradation data of Ph and 4-IPP. These results indicate that Ph and 4-IPP undergo degradation predominantly at the bubble/solution interface, whereas RhB undergoes degradation at both bubble/solution interface and in the bulk solution.

Knowledge-based method for the validation of complex simulation models

In traditional research, the validation of simulation models is mainly based on statistical analysis and simulation error evaluating. As simulation models become more and more complex, simulation behavior is more complicated and heavily dependent on simulation conditions, traditional method cannot be applied directly. On the other hand, measured data needed for traditional methods cannot always be available. What’s more, the validation of complex models is usually costly and time-consuming. This research makes effort to settle the problems above. It provides three aspects of advantage for model validation. First, complicated simulation behavior is abstracted and classified as five categories, among which behavior relationship and aggregative behavior is unique for complex simulation models. And the analysis and validation method of each kind of behavior is proposed. Second, besides measured data of real system, it proposed to utilize experience of expert and other kind of domain knowledge for validation task. And third, the simulation analysis and validation method proposed can be implemented in knowledge system and accomplish validation task automatically. Simulation output analysis is the most important step in model validation. Besides classical continuous dynamic fitting and statistical consistency analysis methods, we propose a domain knowledge-based method for the validation of relationship among behavior segments and aggregative behavior which is unique for complex simulation models. Domain knowledge takes the role of reference in model validation, and it varies from measured data of real system to qualitative experience of experts. Knowledge-based system is implemented based on domain knowledge and validation techniques proposed. Validation of electromagnetic rail gun simulation models are introduced as an example. It has been found that this method can provides an automatic validation way for complex simulation models, and validation tasks can be accomplished efficiently.

DETECTING DEFECTS IN OR BEHIND TUNNEL LINING CONCRETE USING ELECTROMAGNETIC WAVE RADAR WITH CHANGE OF ANTENNA TYPE AND FREQUENCY DOMAIN

The presence of defects (including cavities et al.) in or behind tunnel lining of concrete is likely to result in collapse. One method of detecting such cavities by non-destructive means is radar. By the way, the cavity of small size and deep depth can't be detected easily by the present radar technology when it applies to civil structures. To overcome these problems and limitations, this study aims to propose and develop a fitting frequency of radar and analysis method for detecting cavities in or behind tunnel lining concrete. Study for a fitting frequency of radar and analysis method is based on the experiments with various types of cavities and change of radar frequencies. As the results, it is clarified that a proposed fitting frequency and analysis method has a possibility of detecting various types of cavitations in or behind tunnel lining concrete.

Kinetic and equilibrium study for the sorption of cadmium(II) ions from aqueous phase by eucalyptus bark

The efficiency of eucalyptus bark as a low cost sorbent for removing cadmium ions from aqueous solution has been investigated in batch mode. The equilibrium data could be well described by the Langmuir isotherm but a worse fit was obtained by the Freundlich model. The five linearized forms of the Langmuir equation as well as the non-linear curve fitting analysis method were discussed. Results show that the non-linear method may be a better way to obtain the Langmuir parameters. Maximum cadmium uptake obtained at a temperature of 20 °C was 14.53 mg g −1. The influence of temperature on the sorption isotherms of cadmium has been also studied. The monolayer sorption capacity increased from 14.53 to 16.47 when the temperature was raised from 20 to 50 °C. The Δ G° values were negative, which indicates that the sorption was spontaneous in nature. The effect of experimental parameters such as contact time, cadmium initial concentration, sorbent dose, temperature, solution initial pH, agitation speed, and ionic strength on the sorption kinetics of cadmium was investigated. Pseudo-second-order model was evaluated using the six linear forms as well as the non-linear curve fitting analysis method. Modeling of kinetic results shows that sorption process is best described by the pseudo-second-order model using the non-linear method. The pseudo-second-order model parameters were function of the initial concentration, the sorbent dose, the solution pH, the agitation speed, the temperature, and the ionic strength.

Batch sorption dynamics and equilibrium for the removal of cadmium ions from aqueous phase using wheat bran

Studies on a batch sorption process using wheat bran as a low cost sorbent was investigated to remove cadmium ions from aqueous solution. The influence of operational conditions such as contact time, cadmium initial concentration, sorbent mass, temperature, solution initial pH, agitation speed and ionic strength on the sorption kinetics of cadmium was studied. Pseudo-second-order model was evaluated using the six linear forms as well as the non-linear curve fitting analysis method. Modeling of kinetic results shows that sorption process is best described by the pseudo-second-order model using the non-linear method. The sorption of cadmium was found to be dependent on initial concentration, sorbent mass, solution pH, agitation speed, temperature, ionic strength and contact time. The value of activation energy (12.38 kJ mol −1) indicates that sorption has a low potential barrier corresponding to a physical process. Sorption equilibrium isotherms at different temperatures was determined and correlated with common isotherm equations such as Langmuir and Freundlich models. It was found that the Langmuir model appears to well fit the isotherm data but a worse correlation was obtained by the Freundlich model. The five Langmuir linear equations as well as the non-linear curve fitting analysis method were discussed. Results show that the non-linear method may be a better way to obtain the Langmuir parameters. Thermodynamic parameters such as Δ H°, Δ S° and Δ G° were calculated. These parameters indicate that the sorption of cadmium by wheat bran is a spontaneous process and physical in nature involving weak forces of attraction and is also endothermic.

Pulse shape analysis of signals from BaF 2 and CeF 3 scintillators for neutron capture experiments

The scope of this work is to study the characteristics of BaF 2 and CeF 3 signals using fast digitizers, which allow the sampling of the signal at very high frequencies and the application of the fitting method for analysis of the recorded pulses. By this procedure particle identification and the reconstruction of pile-up events can be improved, while maintaining the energy and time-of-flight resolution as compared to traditional methods. The reliability of the technique and problems connected with data acquisition are discussed with respect to accurate measurements of neutron capture cross-sections.

An experimental analysis of the linear vibration of axisymmetric liquid bridges

The linear vibration of axisymmetric liquid bridges of millimetric size was analyzed experimentally. The equilibrium shape and the evolution of the interface position were recorded by a high-speed video camera. To calculate the surface tension, the Theoretical Image Fitting Analysis method was adapted to process images of liquid bridges at equilibrium. An image processing method was developed to obtain both the position of the solid supports delimiting the liquid bridge and the interface deformation as a function of time. The former allows one to accurately measure the inertial force acting on the liquid bridge. The interface deformation was determined at the subpixel level, so that vibrations of very small amplitude could be analyzed. The results are compared with various theoretical approaches in the linear regime.

Self consistent fitting method for defect analysis by low-frequency noise measurements in reverse biased p- n junctions

A method for analysis of defects close to a metallurgical junction in the space charge region of a reverse biased degraded p- n junction by low-frequency current noise and current-voltage measurements at room temperature is given. The current g-r noise spectrum (separated from the total low-frequency noise spectrum) and the current-voltage characteristics are used to calculate defect parameters like defect density, energy level, capture coefficients and defect region boundary by fitting the theoretical and experimental results in a self-consistent way. This procedure is used to analyse the defects in a silicon field plated PIN photodiode with a soft current-voltage characteristic. It is found that the defects which are responsible for the soft current-voltage characteristics and low-frequency excess g-r noise are distributed up to a distance of 3 μm from the metallurgical junction.