scholarly journals Estimation of Activity Interaction Parameters in Fe-S-j Systems

Entropy ◽  
2018 ◽  
Vol 20 (10) ◽  
pp. 808 ◽  
Author(s):  
Tianhua Ju ◽  
Xueyong Ding ◽  
Yingyi Zhang ◽  
Weiliang Chen ◽  
Xiangkui Cheng ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Excess Entropy ◽  
Geometric Model ◽  
Calculation Model ◽  
Interaction Parameters ◽  
Mixing Enthalpy ◽  
Predicted Values ◽  
Experimental Values ◽  
Activity Interaction Parameter ◽  
Good Agreement

It is important to know the activity interaction parameters between components in melts in the process of metallurgy. However, it’s considerably difficult to measure them experimentally, relying still to a large extent on theoretical calculations. In this paper, the first-order activity interaction parameter (esj) of j on sulphur in Fe-based melts at 1873 K is investigated by a calculation model established by combining the Miedema model and Toop-Hillert geometric model as well as considering excess entropy and mixing enthalpy. We consider two strategies, with or without using excess entropy in the calculations. Our results show that: (1) the predicted values are in good agreement with those recommended by Japan Society for Promotion of Science (JSPS); and (2) the agreement is even better when excess entropy is considered in the calculations. In addition, the deviations of our theoretical results from experimental values eS(exp)j-eS(cal)j depend on the element j’s locations in the periodic table.

Electron transport properties of InP

1980 ◽  
Vol 58 (7) ◽  
pp. 923-930 ◽  
Author(s):  
H. J. Lee ◽  
J. Basinski ◽  
L. Y. Juravel ◽  
J. C. Woolley
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Thermoelectric Power ◽  
Room Temperature ◽  
Theoretical Calculations ◽  
Scattering Parameters ◽  
Electron Transport Properties ◽  
Predicted Values ◽  
Experimental Values ◽  
Good Agreement

Measurements of electrical conductivity σ and Hall coefficient RH have been made as a function of temperature in the range room temperature to 250 °C and as a function of magnetic field up to 3.2 T on single crystal n-type samples of InP with carrier concentrations in the range 3.5 × 1021 to 1.2 × 1024 m−3. Theoretical calculations of σ and RH have been made using the method of Fletcher and Butcher and the resulting values fitted to the experimental data by using various scattering parameters as adjustable. The parameters so obtained have then been used to predict further magnetoresistance values and values of thermoelectric power and Nernst–Ettingshausen coefficient. The predicted values of magnetoresistance and thermoelectric power show good agreement with experimental values but not those of the Nernst–Ettingshausen coefficient, possibly due to experimental problems.

The Thermodynamics Calculation of Mg-Zn Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 447-450
Author(s):  
Tian Mo Liu ◽  
Hong Yi Zhou ◽  
Fu Sheng Pan
Keyword(s):  
Excess Entropy ◽  
Formation Enthalpy ◽  
Miedema Model ◽  
Activity Curve ◽  
Calculation Results ◽  
Experimental Values ◽  
Zn Alloy ◽  
Zn Alloys ◽  
Good Agreement

In the present work Miedema model has been developed, and the formation enthalpy of Mg-Zn alloys and the activity curve of Zn in Mg-Zn alloy at 1000K have been calculated according to the Miedema model. The calculation results showed that the formation enthalpy of Mg-Zn was small, and the excess entropy attributes a lot to the result. When excess enthopy was considered, the calculation results were found to be in good agreement with the experimental values.

TEMPERATURE EFFECT ON THERMOMECHANICAL PROPERTIES OF BERYLLIUM CHALCOGENIDES BeS, BeSe AND BeTe

2006 ◽  
Vol 20 (01) ◽  
pp. 49-61 ◽  
Author(s):  
F. BENKABOU
Keyword(s):  
Elastic Constants ◽  
Dynamic Properties ◽  
Theoretical Calculations ◽  
Thermomechanical Properties ◽  
Structural Dynamic ◽  
Experimental Values ◽  
Beryllium Chalcogenides ◽  
Increasing Temperature ◽  
And Diffusion ◽  
Good Agreement

We have used the molecular-dynamic method for the calculation of the structural, dynamic and elastic properties of group BeS , BeSe and BeTe compounds for temperature ranging from 300 to 1200 K. Tersoff potential has been used to model the interaction between the groups II–VI compound atoms. The structural properties of cubic BeS , BeSe and BeTe have been calculated, and good agreement between the calculated and experimental values have been found. We have also predicted the elastic constants and diffusion coefficients of BeS , BeSe and BeTe . The values found compare very well with the theoretical results. For the temperature range under study, all elastic constants and dynamic properties show a softening with increasing temperature very similar to the theoretical calculations.

scholarly journals Synthesis, characterization and theoretical calculations of Cu(I) complex of trithiocyanuric acid [Cu(ttc)3]

2018 ◽  
Vol 23 (2) ◽  
pp. 241-266 ◽  
Author(s):  
Ximena Verónica Jaramillo-Fierro ◽  
César Zambrano ◽  
Francisco Fernández ◽  
Regino Saenz-Puche ◽  
César Costa ◽  
...  
Keyword(s):  
Computational Study ◽  
Theoretical Calculations ◽  
Photophysical Properties ◽  
Vibrational Frequencies ◽  
Basis Sets ◽  
Vertical Excitation ◽  
Experimental Values ◽  
Homo Lumo ◽  
Perchlorate Hexahydrate ◽  
Good Agreement

A new Cu(I) complex constructed by reaction of trithiocyanuric acid (ttc) and copper (II) perchlorate hexahydrate has been successfully synthesized by a slow sedimentation method in a DMF solvent at room temperature. The molecular structure of the compound was elucidated by MALDI-TOFMS, UV Vis and FTIR spectroscopy, DSC-TGA analysis and magnetic susceptibility measurement. The proposed structure was corroborated by a computational study carried out with the Gaussian09 and AIMAII programs using the RB3LYP hybrid DFT functional with both 6-31G and Alhrich-TZV basis sets. The calculated vibrational frequencies values were compared with experimental FTIR values. Photophysical properties of the synthesized complex were evaluated by UV-Visible spectroscopy and compared with computed vertical excitation obtained from TDDFT. The theoretical vibrational frequencies and the UV Vis spectra are in good agreement with the experimental values. Additionally, the Frontier Molecular Orbitals (HOMO-LUMO) and the Molecular Electrostatic Potential of the complex was calculated using same theoretical approximation. The results showed the interaction between three coordinatedl igand atoms and the Cu(I) ion.

scholarly journals Effects of Parameters on Solvent Extraction of Oil From Sandbox (Hura Crepitans) Seed Oil Using 2^4 Factorial Design

2021 ◽  
Vol 15 ◽  
pp. 48-55
Author(s):  
Owhor Sampson Chisa ◽  
J. D. Amine ◽  
Abdul Gambo Alim ◽  
Luka Bobby Shakarau ◽  
Isaiah Kehinde Ogbobame ◽  
...  
Keyword(s):  
Solvent Extraction ◽  
Seed Oil ◽  
Hydraulic Press ◽  
Biodiesel Production ◽  
Extraction Temperature ◽  
Physiochemical Properties ◽  
Hura Crepitans ◽  
Predicted Values ◽  
Experimental Values ◽  
Good Agreement

The present work deals with the production of biodiesel from Sandbox (Hura crepitans) seed oil and the optimization of the parameters that influence the transesterification of Sandbox (Hura crepitans)seed oil into biodiesel using Response Surface Methodology. Hura crepitans oil was obtained from by using hydraulic press for Mechanical and n-hexane for solvent extraction. Esterification was done using methanol and sodium hydroxide. A total of 48 experiments using Central Composite Design were carried out. The R-Squared, Adequate Precision, Predicted and Adjusted R-Squared values were 0.9367, 19.219, 0.8576 and 0.9070 respectively. The result of the extraction of oil, physiochemical properties, and optimization process shows that sandbox (Hura crepitans) seed oil has characteristics that are more favorable to biodiesel production. The optimal conditions for extraction of oil from sandbox seed oil were given as alcohol/ oil ratio of 5.0, catalyst amount of 20 g/ml, extraction temperature of 60 ºC, and extraction time of 45.01 minutes, with the predicted oil yield as 97.33% respectively which shows that the experimental values are in good agreement with predicted values.

The β+ Decay of 234Np and Other Isospin-Forbidden 0+→ 0+ Fermi Transitions

1984 ◽  
Vol 39 (12) ◽  
pp. 1168-1171
Author(s):  
C. T. Yap ◽  
E. L. Saw
Keyword(s):  
Nuclear Matrix ◽  
Coulomb Potential ◽  
Deformation Parameter ◽  
Theoretical Calculations ◽  
Wave Functions ◽  
Matrix Elements ◽  
Β Decay ◽  
A Value ◽  
Experimental Values ◽  
Good Agreement

Although experimental values of the Fermi nuclear matrix elements vary widely from about 1 × 10-3 to 40 × 10-3 for isospin-forbidden 0+→0+ β transitions, theoretical calculations using the Coulomb potential and Nilsson wave functions yielded values of MF in reasonably good agreement, except that of 234Np. However, our calculation of MF for this decay as a function of the deformation parameter β yielded a value of MF in good agreement with experiment for values of β between 0.1 and 0.2.

An Analytical Examination of the Combustion of a Turbulent Jet in an Environment of Air Containing a Premixed Fuel or a Diluent

1995 ◽  
Vol 117 (3) ◽  
pp. 234-238 ◽  
Author(s):  
P. Wierzba ◽  
G. A. Karim ◽  
I. Wierzba
Keyword(s):  
Flame Length ◽  
Turbulent Jet ◽  
Simple Analytical Model ◽  
Flammability Limits ◽  
Gaseous Fuels ◽  
Gaseous Environment ◽  
Fuel Jet ◽  
Predicted Values ◽  
Experimental Values ◽  
Good Agreement

A simple analytical model for the mixing and combustion of an axisymmetric turbulent gaseous fuel jet discharging into a co-flowing streaming gaseous environment of an auxiliary fuel and/or a diluent homogeneously mixed with air is presented. A number of gaseous fuels and diluents are considered. It is shown that the combustion characteristics of a fuel jet can be modified significantly by the presence of a relatively small amount of a fuel in the surrounding air at concentrations well below the corresponding local flammability limits. Correlative procedures are presented for estimating changes in the flame length, the size of the combustion zone, and the blowout limits with changes in the type and concentration of the fuel in the surroundings. Predicted values showed generally good agreement with the corresponding experimental values.

A Thermodynamic Analysis of the Rich Flammability Limits of Fuel-Diluent Mixtures in Air

1995 ◽  
Vol 117 (3) ◽  
pp. 239-242 ◽  
Author(s):  
S. O. Bade Shrestha ◽  
I. Wierzba ◽  
G. A. Karim
Keyword(s):  
Atmospheric Temperature ◽  
Flammability Limit ◽  
Flammability Limits ◽  
Wide Range ◽  
Temperature And Pressure ◽  
The Rich ◽  
Predicted Values ◽  
Experimental Values ◽  
Good Agreement ◽  
Propane Butane

A simple approach is described for the calculation of the rich flammability limits of fuel-diluent mixtures in air for a wide range of initial temperatures based only on the knowledge of the flammability limit of the pure fuel in air at atmospheric temperature and pressure conditions. Various fuel-diluent mixtures that include the fuels methane, ethylene, ethane, propane, butane, carbon monoxide, and hydrogen, and the diluents nitrogen, carbon dioxide, helium, and argon have been considered. Good agreement is shown to exist between predicted values of the rich flammability limits and the corresponding available experimental values for the fuel-diluent mixtures.

scholarly journals Modeling of Hydrodynamics in a 25 mm ϕ Pulsed Disk and Doughnut Column

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Rajnish Kumar ◽  
D. Sivakumar ◽  
Shekhar Kumar ◽  
U. Kamachi Mudali
Keyword(s):  
Slip Velocity ◽  
Drop Size ◽  
Absolute Error ◽  
Model Parameters ◽  
Dispersed Phase ◽  
Acid System ◽  
Hydrodynamic Parameters ◽  
Predicted Values ◽  
Experimental Values ◽  
Good Agreement

The hydrodynamic parameters, namely, dispersed phase holdup and flooding throughput, have been investigated in 25 mm diameter pulsed disk and doughnut column (PDDC), in no mass transfer conditions. In this work, using existing correlations on plate pulsed columns, the dispersed phase holdup and the flooding throughput are empirically modelled well using the slip velocity concept. A good agreement is observed between experimental values and predicted values obtained from empirical correlation. The experimental data for dispersed phase holdup and flooding throughput has been modelled using the Van Delden model to describe the hydrodynamics characteristics of a PDDC and necessary adjustable parameters for drop size distribution and dispersed phase holdup are updated for 30% TBP-nitric acid system. The model parameters were estimated by minimizing the absolute error between experimental and theoretical values of flooding throughput and holdup data. It was found that the measured values and observed trends could be described accurately using this model after fitting holdup and flooding data. The error between the experimental and theoretical values of flooding throughput and holdup was found to be less than 10%.

Optimization of Nigerian Restaurant Waste Cooking Biodiesel Reaction Parameters using Response Surface Methodology

2014 ◽  
Vol 3 (4) ◽  
pp. 21-33
Author(s):  
M.A. Waheed ◽  
O.D. Samuel ◽  
B.O. Bolaji ◽  
O.U. Dairo
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Maximum Yield ◽  
Waste Cooking Oil ◽  
Molar Ratio ◽  
Optimization Parameters ◽  
Predicted Values ◽  
Experimental Values ◽  
Restaurant Waste ◽  
Good Agreement

The present work deals with the production of biodiesel from Nigerian restaurant waste cooking oil (NRWCO) and the optimization of the parameters that influences the alkaline transesterification of NRWCO into biodiesel using response surface methodology. The optimization parameters like oil: oil/methanol molar ratio, catalyst amount and reaction time were done using Design Expert 6.06 software. It was found that the maximum yield of biodiesel was obtained in 79.8 min for 1: 5.9, oil: methanol ratio, 1.2 wt. % KOH amount. A total of 20 experiments using Central Composite Design were carried out. The R2, adjusted R2 and predicted R2 values were 0.982, 0.9657 and 0.9088 respectively show that the experimental values are in good agreement with the predicted values. The properties of biodiesel at the optimized parameters, thus, produced confirm to the ASTM, EN and BIS specifications, making it an ideal alternative fuel for diesel engine.

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