Showing papers in "Journal of Physical and Chemical Reference Data in 2006"
TL;DR: In this article, a comprehensive database on physical properties of ionic liquids (ILs), collected from 109 kinds of literature sources in the period from 1984 through 2004, has been presented, which includes 1680 pieces of data on the physical properties for 588 available ILs, from which 276 kinds of cations and 55 kinds of anions were extracted.
Abstract: A comprehensive database on physical properties of ionic liquids (ILs), which was collected from 109 kinds of literature sources in the period from 1984 through 2004, has been presented. There are 1680 pieces of data on the physical properties for 588 available ILs, from which 276 kinds of cations and 55 kinds of anions were extracted. In terms of the collected database, the structure-property relationship was evaluated. The correlation of melting points of two most common systems, disubstituted imidazolium tetrafluoroborate and disubstituted imidazolium hexafluorophosphate, was carried out using a quantitative structure-property relationship method.
1,102 citations
TL;DR: In this article, the authors collected and reviewed cross sections for total scattering, elastic scattering, momentum transfer, excitations of rotational, vibrational, and electronic states, dissociation, ionization, and emission of radiation.
Abstract: Cross section data have been compiled for electron collisions with nitrogen molecules, based on 104 references. Cross sections are collected and reviewed for: total scattering, elastic scattering, momentum transfer, excitations of rotational, vibrational, and electronic states, dissociation, ionization, and emission of radiation. For each process, the recommended values of the cross section are presented for use. The literature has been surveyed through the end of 2003.
712 citations
TL;DR: In this paper, a semitheoretical approach for the ionization constant of water, KW, was used to fit the available experimental data over wide ranges of density and temperature.
Abstract: A semitheoretical approach for the ionization constant of water, KW, is used to fit the available experimental data over wide ranges of density and temperature. Statistical thermodynamics is employed to formulate a number of contributions to the standard state chemical potential of the ionic hydration process. A sorption model is developed for calculating the inner-shell term, which accounts for the ion–water interactions in the immediate ion vicinity. A new analytical expression is derived using the Bragg–Williams approximation that reproduces the dependence of a mean ion solvation number on the solvent chemical potential. The proposed model was found to be correct at the zero-density limit. The final formulation has a simple analytical form, includes seven adjustable parameters, and provides good fitting of the collected KW data, within experimental uncertainties, for a temperature range of 0–800 °C and densities of 0–1.2 g cm−3.
512 citations
TL;DR: In this article, the available experimental data for the density and viscosity of liquid aluminum and iron have been critically examined with the intention of establishing a density and a visosity standard, and the overall uncertainty in the absolute values of the density is estimated to be one of ± 0.7% for aluminum and 0.8% for iron.
Abstract: The available experimental data for the density and viscosity of liquid aluminum and iron have been critically examined with the intention of establishing a density and a viscosity standard. All experimental data have been categorized into primary and secondary data according to the quality of measurement specified by a series of criteria. The proposed standard reference correlations for the density of the aluminum and iron are characterized by standard deviations of 0.65% and 0.77% at the 95% confidence level, respectively. The overall uncertainty in the absolute values of the density is estimated to be one of ±0.7% for aluminum and 0.8% for iron, which is worse than that of the most optimistic claims but recognizes the unexplained discrepancies between different methods. The standard reference correlations for the viscosity of aluminum and iron are characterized by standard deviations of 13.7% and 5.7% at the 95% confidence level, respectively. The uncertainty in the absolute values of the viscosity of the two metals is thought to be no larger than the scatter between measurements made with different techniques and so can be said to be ±14% in the case of aluminum and ±6% in the case of iron.
366 citations
TL;DR: In this paper, a Gibbs energy function g(T,p) of temperature and pressure, covering the ranges 0 −273.16 K and 0 −210 MPa, expressed in the temperature scale ITS-90, is presented.
Abstract: Various thermodynamic equilibrium properties of naturally abundant, hexagonal ice (ice Ih) of water (H2O) have been used to develop a Gibbs energy function g(T,p) of temperature and pressure, covering the ranges 0–273.16 K and 0 Pa–210 MPa, expressed in the temperature scale ITS-90. It serves as a fundamental equation from which additional properties are obtained as partial derivatives by thermodynamic rules. Extending previously developed Gibbs functions, it covers the entire existence region of ice Ih in the T-p diagram. Close to zero temperature, it obeys the theoretical cubic limiting law of Debye for heat capacity and Pauling’s residual entropy. It is based on a significantly enlarged experimental data set compared to its predecessors. Due to the inherent thermodynamic cross relations, the formulas for particular quantities like density, thermal expansion, or compressibility are thus fully consistent with each other, are more reliable now, and extended in their ranges of validity. In conjunction with the IAPWS-95 formulation for the fluid phases of water, the new chemical potential of ice allows an alternative computation of the melting and sublimation curves, being improved especially near the triple point, and valid down to 130 K sublimation temperature. It provides an absolute entropy reference value for liquid water at the triple point.
315 citations
TL;DR: In this paper, a new, expanded tabulation of the atomic transition probabilities for allowed and forbidden lines of Fe I and Fe II was carried out based on the critical evaluation of all available literature sources.
Abstract: We have carried out a new, expanded tabulation of the atomic transition probabilities for allowed and forbidden lines of Fe I and Fe II, based on the critical evaluation of all available literature sources. The compiled data are taken mainly from recent experimental and theoretical results that became available after the publication of our first compilation in 1988. The data are arranged in multiplet format and are ordered according to increasing excitation energies.
194 citations
TL;DR: A new formulation for the thermodynamic properties of the fluid phase of ethane in the form of a fundamental equation explicit in the Helmholtz energy is presented in this paper, where the functional form of the residual part was developed using state-of-the-art linear and nonlinear optimization algorithms.
Abstract: A new formulation for the thermodynamic properties of the fluid phase of ethane in the form of a fundamental equation explicit in the Helmholtz energy is presented The functional form of the residual part was developed using state-of-the-art linear and nonlinear optimization algorithms It contains 44 coefficients which were fitted to selected data for the thermal and caloric properties of ethane both in the single-phase region and on the liquid–vapor phase boundary This work provides information on the available experimental data for the thermodynamic properties of ethane and presents all details of the new formulation The new equation of state describes the pρT surface of ethane with an uncertainty in density of less than 002%–003% (coverage factor k=2 corresponding to a level of confidence of about 95%) from the melting line up to temperatures of 520 K and pressures of 30 MPa In the gaseous and supercritical region, high precision speed of sound data are represented generally within less than 00
170 citations
TL;DR: In this article, the thermodynamic properties of fluid phase n-butane and isobutane in the form of fundamental equations explicit in the Helmholtz energy are presented.
Abstract: New formulations for the thermodynamic properties of fluid phase n-butane and isobutane in the form of fundamental equations explicit in the Helmholtz energy are presented. The functional form of the correlation equations for the residual parts was developed simultaneously for both substances considering data for the thermodynamic properties of ethane, propane, n-butane, and isobutane. Each contains 25 coefficients which were fitted to selected data for the thermal and caloric properties of the respective fluid both in the single-phase region and on the vapor–liquid phase boundary. This work provides information on the available experimental data for the thermodynamic properties of n- and isobutane, and presents all details of the new formulations. The new equations of state describe the pρT surfaces with uncertainties in density of 0.02% (coverage factor k=2 corresponding to a confidence level of about 95%) from the melting line up to temperatures of 340 K and pressures of 12 MPa. The available reliable ...
160 citations
TL;DR: In this article, the authors proposed a value for the viscosity of liquid toluene at 298.15 K and 0.1 MPa is 554.3 Pas.
Abstract: Viscosity is an important transport property for the optimum design of a chemical process plant and for the development of molecular theories of the liquid state. A large amount of experimental viscosity data has been produced for all types of liquids, from alternative refrigerants to molten salts and molten metals. The accuracy of these data is related to the operating conditions of the instrument and, for this purpose as well as for the calibration of relative instruments, standard reference data for viscosity are necessary over a wide range of temperatures. New experimental data on the viscosity of liquid toluene along the saturation line have been obtained recently, mostly at low temperatures. The quality of the data is such that recommended values can be proposed with uncertainties of 0.5% 95% confidence level for 260 KT370 K and 2% for 210 KT 260 K and 370 KT400 K. A discussion about the uncertainties in the measurements and about the purity of the samples is made. The proposed value for the viscosity of liquid toluene at 298.15 K and 0.1 MPa is 554.23.3 Pas. © 2006 American Institute of Physics. DOI: 10.1063/1.1928233
131 citations
TL;DR: In this paper, energy levels, with designations and uncertainties, have been compiled for the spectra of the neutral atom and all positive ions of rubidium (Z=37).
Abstract: Energy levels, with designations and uncertainties, have been compiled for the spectra of the neutral atom and all positive ions of rubidium (Z=37). Wavelengths with classifications, intensities, and transition probabilities are also tabulated. In addition, ground states and ionization energies are listed. For most ionization stages experimental data are available; however for ionization stages where only theoretical calculations or fitted values exist, these are reported. There are a few ionization stages for which only a calculated ionization potential is available.
121 citations
TL;DR: In this paper, the components extracted from wood with a specified solvent represent the solubility of wood in that solvent at the condition described, i.e., high severities are needed for increased solubability/liquefaction due to temperature, time, and catalytic effects.
Abstract: Wood is a complex and nonuniform material. Its overall solubility is a combination of the individual components’ ability to come into contact with the specified solvent (e.g., acetone) or blend. The components extracted from wood with a specified solvent represent the solubility of wood in that solvent at the condition described. Some wood compounds are soluble in water and organic solvents but the integral part of the cellular structure cannot be removed by common solvents at ambient temperature. High severities are needed for increased solubility/liquefaction due to temperature, time, and catalytic effects.
TL;DR: In this article, a new reference-quality correlation for the viscosity of methanol is presented that is valid over the entire fluid region, including vapor, liquid, and metastable phases.
Abstract: A new reference-quality correlation for the viscosity of methanol is presented that is valid over the entire fluid region, including vapor, liquid, and metastable phases. To describe the zero-density viscosity with kinetic theory for polar gases, a new expression for the collision integral of the Stockmayer potential is introduced. The initial density dependence is based on the Rainwater‐Friend theory. A new correlation for the third viscosity virial coefficient is developed from experimental data and applied to methanol. The high-density contribution to the viscosity is based on the Chapman‐Enskog theory and includes a new expression for the hard-sphere diameter that is a function of both temperature and density. The resulting correlation is applicable for temperatures from the triple point to 630 K at pressures up to 8 GPa. The estimated uncertainty of the resulting correlation with a coverage factor of 2 varies from 0.6% in the dilute-gas phase between room temperature and 630 K, to less than 2% for the liquid phase at pressures up to 30 MPa at temperatures between 273 and 343 K, 3% for pressures from 30 to 100 MPa, 5% for the liquid from 100 to 500 MPa, and 10% between 500 MPa and 4 GPa. At very high pressures, from 4 to 8 GPa, the correlation has an estimated uncertainty of 30% and can be used to indicate qualitative behavior. © 2006 by the U.S. Secretary of Commerce
TL;DR: In this article, energy levels, wavelengths, and transition probabilities of the first and second spectra of tungsten, W I and W II, were derived from a critical evaluation of the available literature.
Abstract: Energy levels, wavelengths, and transition probabilities of the first and second spectra of tungsten, W I and W II, have been compiled. Wavelengths of observed transitions and energy levels derived from those wavelengths have been obtained from a critical evaluation of the available literature. Measured transition probabilities for some of the observed transitions have been compiled from the published literature.
TL;DR: In this article, theoretical electron impact cross sections at typical etching plasma energies (sub 10 eV) are presented for the CFx (x=1-3) active radical species in a form suitable for plasma modeling.
Abstract: The supply of absolute electron-impact cross sections for molecular targets and radicals is extremely important for developing plasma reactors and testing different types of etching gases. Current demand for such models is high as the industry aims to replace traditional plasma processing gases with less polluting species. New theoretical electron impact cross sections at typical etching plasma energies (sub 10 eV) are presented for the CFx (x=1-3) active radical species in a form suitable for plasma modeling. The available experimental and theoretical data are summarized for two potential feed gases, CF3I and C2F4. This data cover recommended cross sections for electron scattering (total, excitation, momentum transfer, and elastic integral), electron impact dissociation, and dissociative electron attachment, wherever possible. Numerical values are given as tables in the paper and are also placed in the electronic archive. (c) 2006 American Institute of Physics.
TL;DR: In this paper, a simple formulation is developed for the accurate estimation of flash points of miscible combustible solvent mixtures, which consists of an equation, which was previously validated for pure compounds, and this procedure allows accurate estimations for ideal and nonideal binary and ternary mixtures.
Abstract: A simple formulation is developed for the accurate estimation of flash points of miscible combustible solvent mixtures. It consists of an equation, which was previously validated for pure compounds. It is shown that this procedure allows accurate estimations for ideal and nonideal binary and ternary mixtures. This method does not need prerequisites such as the lower flammability limits of pure components and the use of the Le Chatelier law.
TL;DR: The recommended liquid-liquid equilibrium (LLE) data for 19 binary 1-alkanol-water systems have been obtained after critical evaluation of all data (527 data sets) reported in the open literature up to the end of 2004 as mentioned in this paper.
Abstract: The recommended liquid–liquid equilibrium (LLE) data for 19 binary 1-alkanol–water systems have been obtained after critical evaluation of all data (527 data sets) reported in the open literature up to the end of 2004. An equation for prediction of the 1-alkanol solubility was developed. The predicted 1-alkanol solubility was used for calculation of water solubility in the second liquid phase. The LLE calculations were done with the equation of state appended with a chemical term proposed by Goral. The recommended data were presented in the form of individual pages containing tables and all the references.
TL;DR: The mutual solubilities and related liquid-liquid equilibria of C10 hydrocarbons with water are exhaustively and critically reviewed in this article, where all the data are expressed as mass percent and mole fraction as well as the originally reported units.
Abstract: The mutual solubilities and related liquid–liquid equilibria of C10 hydrocarbons with water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 20 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For ten systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of the all experimental data for a given homologous series of aliphatic and aromatic hydrocarbons was used.
TL;DR: In this article, the authors applied G3(MP2) theory to evaluate the thermodynamic data of CH3SiCl3 (methyltrichlorosilane) (MTS) gas.
Abstract: CH3SiCl3 (methyltrichlorosilane) (MTS) is one of the most important precursors for manufacturing both an oxidation resistant SiC coating and a functional SiC film by chemical vapor deposition (CVD). In order to analyze the decomposition products of MTS with a thermodynamic calculation, correct thermodynamic data must be obtained from the authoritative data sources. G3(MP2) has been applied to evaluate the thermodynamic data of MTS(gas). The calculated value of the Gibbs energy of formation, ΔfGm0(298.15K)=−490.13kJ∙mol−1, compares with a value, ΔfGm0(298.15K)=−468.02kJ∙mol−1 from the 4th edition of the NIST-JANAF Thermochemical Tables. Further analyses have been conducted: (1) by using G3, G3//B3LYP, and G3(MP2)//B3LYP theories; (2) by using variable scale factors for G3(MP2) theory; and (3) by investigating the accuracy of both experimental and calculated thermodynamic data. The calculated values can provide ΔfGm0 values for MTS above 1500K. The final fitted equation for MTS(gas) is: ΔfGm0=7.5763×10−6T2+...
TL;DR: The mutual solubilities and related liquid-liquid equilibria of C13-C36 hydrocarbons with water were exhaustively and critically reviewed in this paper. But the authors did not provide a detailed analysis of the experimental data.
Abstract: The mutual solubilities and related liquid–liquid equilibria of C13–C36 hydrocarbons with water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 56 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For 17 systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of all the experimental data for a given homologous series of aliphatic and aromatic hydrocarbons was used.
TL;DR: In this paper, a comprehensive review of experimental data on the limiting activity coefficients γ1∞, partial molar excess enthalpies H¯1E,∞ and heat capacities C¯p, 1E, ∞ of lower 1-alkanols (C1-C5) in water is presented.
Abstract: A comprehensive review is presented of experimental data on the limiting activity coefficients γ1∞, infinite dilution partial molar excess enthalpies H¯1E,∞ and heat capacities C¯p,1E,∞ of lower 1-alkanols (C1–C5) in water. For each alkanol, the compiled data are critically evaluated and correlated with a suitable model equation providing adequate simultaneous description of the equilibrium measurements and the calorimetric information. As a result, recommended thermodynamically consistent temperature dependences of γ1∞, H¯1E,∞, and C¯p,1E,∞ of superior accuracy are established in the range from the melting point to the normal boiling point of water. In addition, by employing literature data on the respective residual properties of the pure 1-alkanols, analogous recommendations are also derived for the temperature dependences of the Henry’s law constants, hydration enthalpies, and hydration heat capacities. Evolution of the various infinite dilution thermodynamic properties of aqueous 1-alkanols with temp...
TL;DR: A group additivity approach used to estimate total phase change entropies of organic molecules applied to 627 of these liquid crystals is found to significantly overestimate their total phase changes.
Abstract: The thermochemical behavior of more than 3000 organic compounds known to form liquid crystals is reported along with references to the original literature. A group additivity approach used to estimate total phase change entropies of organic molecules applied to 627 of these liquid crystals is found to significantly overestimate their total phase change entropies. Comparison of experimental and estimated values also show significant scatter relative to database compounds. The origins of these discrepancies are discussed in terms of a model used to explain liquid crystal formation. © 2006 American Institute of Physics. DOI: 10.1063/1.1901689
TL;DR: In this paper, a new thermal conductivity equation λ =λ(T,ρ) in a multiparameter format was developed for carbon dioxide through the application of an optimization technique of the functional form, valid for temperatures from the triple point (Tt=216.592K; Pt=0.51795MPa) to 1000K and pressures up to 200MPa.
Abstract: A new thermal conductivity equation λ=λ(T,ρ) in a multiparameter format was developed for carbon dioxide through the application of an optimization technique of the functional form. The proposed equation is valid for temperatures from the triple point (Tt=216.592K; Pt=0.51795MPa) to 1000K and pressures up to 200MPa. The calculation of density, which is an independent variable of the equation, from the experimental (T,P) conditions is performed with a high accuracy equation of state for the fluid. The thermal conductivity equation shows an average absolute deviation of 1.19% on the selected 1407 primary data points. Its performances are slightly better than those of the corresponding conventional model by Vesovic et al. [J. Phys. Chem. Ref. Data 19, 763 (1990)] available from the literature; moreover the new equation is simpler to use in particular for the near-critical region. Tables of generated values of carbon dioxide thermal conductivity are provided for check of the code implementations and for quick...
TL;DR: In this article, a fragment constant model based on five fragment constants and one structural correction factor was developed for predicting log octanol-air partition coefficient at temperatures ranging from 10 to 40°C.
Abstract: The octanol–air partition coefficient (KOA) is a key physicochemical parameter for describing the partition of organic pollutants between air and environmental organic phases Experimental determination of KOA is costly and time consuming, and sometimes restricted by lack of sufficiently pure chemicals There is a need to develop a simple but accurate method to estimate KOA In the present study, a fragment constant model based on five fragment constants and one structural correction factor, was developed for predicting logKOA at temperatures ranging from 10 to 40°C The model was validated as successful by statistical analysis and external experimental logKOA data Compared to other quantitative structure–property relationship methods, the present model has the advantage that it is much easier to implement As aromatic compounds that contain C, H, O, Cl, and Br atoms, were included in the training set used to develop the model, the current fragment model applies to a wide range of chlorinated and bromina
TL;DR: In this article, a predictive method based on Benson's group additivity technique was developed for calculating the enthalpy of formation in the solid phase, at 298.15K, of carbon-hydrogen compounds and carbonhydrogen-oxygen compounds.
Abstract: A predictive method, based on Benson’s group additivity technique, is developed for calculating the enthalpy of formation in the solid phase, at 298.15K, of carbon-hydrogen compounds and carbon-hydrogen-oxygen compounds. A complete database compiles 398 experimental enthalpies of formation. The whole group contribution values, ring strain corrections, and nonnearest neighbor interactions evaluated are listed. Finally a comparison with Cohen’s method indicates that this new estimation method leads to higher precision and reliability.
TL;DR: The mutual solubilities and related liquid-liquid equilibria of C11 and C12 hydrocarbons with water and heavy water were exhaustively and critically reviewed in this paper.
Abstract: The mutual solubilities and related liquid–liquid equilibria of C11 and C12 hydrocarbons with water and heavy water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 24 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For 12 systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of all the experimental data for a given series of aliphatic and aromatic hydrocarbons was used.
TL;DR: Reference tables of second pVT-virial coefficients B(T), viscosity T, and self-diffusion T for all neat alkanes CnH2n+2, n 12 is given in this paper.
Abstract: Reference tables of second pVT-virial coefficients B(T), viscosity η(T), and self-diffusion ρD(T) are given for all neat alkanes CnH2n+2, n 12 is independent of T. The LJTDP has been used before in order to construct reference tables of thermophysical properties of neat gases [Zarkova and Hohm, J. Phys. Chem. Ref. Data 31, 183 (2002)] and binary mixtures [Zarkova, Hohm, and Damyanova, J. Phys. Chem. Ref. Data 32, 1591 (2003)]. However, those studies were restricted to atoms and globularly shaped nondipolar molecules. Here the approach...
TL;DR: In this paper, a new parameterization of the Laidler method for estimation of atomization enthalpies and standard enthpies of formation at 298.15 K for several families of hydrocarbons alkanes, alkenes, alkynes, polyenes, poly-ynes, alkyl radicals, cycloalkanes, cycloencane derivatives, and polyaromatics is presented.
Abstract: A new parameterization of the Laidler method for estimation of atomization enthalpies and standard enthalpies of formation at 298.15 K for several families of hydrocarbons alkanes, alkenes, alkynes, polyenes, poly-ynes, alkyl radicals, cycloalkanes, cycloalkenes, benzene derivatives, and polyaromatics is presented. A total of 200 compounds 164 for liquid phase are used for the calculation of the parameters. Comparison between the experimental values and those calculated using the group additive scheme led to an
TL;DR: The experimental data on elementary processes (collisional deactivation, chemical reactions, photodissociation) involving spin-orbitally excited X(2P1/2) atoms (X=F,Cl,Br,I) published up to the middle of 2005 are summarized in the present compilation.
Abstract: The experimental data on elementary processes (collisional deactivation, chemical reactions, photodissociation) involving spin-orbitally excited X(2P1/2) atoms (X=F,Cl,Br,I) published up to the middle of 2005 are summarized in the present compilation. Critical evaluation of the data and limited comparison to theoretical calculations are also presented.
TL;DR: The mutual solubility of C5−C26 hydrocarbons with seawater is exhaustively and critically reviewed in this article, where all the data are expressed as mass percent and mole fraction as well as originally reported units.
Abstract: The mutual solubility of C5–C26 hydrocarbons with seawater is exhaustively and critically reviewed. Reports of experimental determination of solubility in 46 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For 15 of these systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units.
TL;DR: In this article, an optimization technique was applied to develop a functional form for a multiparameter viscosity equation η=η(ρ,T) for R134a.
Abstract: An optimization technique was applied to develop a functional form for a multiparameter viscosity equation η=η(ρ,T) for R134a. The results obtained are very promising, with an average absolute deviation of 0.55% for the currently available 549 primary data points. Compared to viscosity equations available in the literature, this is a significant improvement. Advantages become evident especially at gaseous states. As usual, both the development and the use of the viscosity equation require a highly accurate equation of state in order to convert the independent variables used for the experimental data and in most applications, (P,T), into the independent variables of the viscosity equation, (ρ,T). Though the equation was developed directly using the available data, the zero-density viscosity and the reduced second viscosity virial coefficient are correctly reproduced in the data range. The technique used to develop the equation, which is heuristic and not theoretically founded, is capable of selecting consi...