A simple melting theory applied to alkali halide, alkaline-earth chalcogenide, and alkali chalco-genide compounds

2005 ◽  
Vol 83 (6) ◽  
pp. 653-660 ◽  
Author(s):  
Quan Liu ◽  
Li-rong Chen
Keyword(s):  
Melting Temperature ◽  
Potential Function ◽  
Alkali Halide ◽  
Alkaline Earth ◽  
Simple Method ◽  
Wide Range ◽  
64.70 Dv ◽  
Experimental Values

A useful and simple method for studying the melting temperature Tm of ion compounds has been developed by using analyses originally due to diffusional force theory, incorporating Pandey's formulation and Harrison's potential function. The calculated values of Tm for a wide range of compounds of types IA–VII (alkali halide), IIA–VI (alkaline-earth chalcogenide), and IA–VI (alkali chalcogenide) are found to agree fairly well with experimental values for Tm and to be superior to results from previous approaches involving similar methods. PACS Nos.: 64.70.Dv, 67.80.Gb

scholarly journals DFT calculation and assignment of vibrational spectra of aryl and alkyl chlorophosphates

2014 ◽  
Vol 12 (2) ◽  
pp. 153-163
Author(s):  
Viktor Anishchenko ◽  
Vladimir Rybachenko ◽  
Konstantin Chotiy ◽  
Andrey Redko
Keyword(s):  
Vibrational Spectra ◽  
Basis Sets ◽  
Heavy Atoms ◽  
Wide Range ◽  
Complete Assignment ◽  
Key Factor ◽  
Polarization Functions ◽  
Experimental Values ◽  
Semi Empirical ◽  
Good Agreement

AbstractDFT calculations of vibrational spectra of chlorophosphates using wide range of basis sets and hybrid functionals were performed. Good agreement between calculated and experimental vibrational spectra was reached by the combination of non-empirical functional PBE0 with both middle and large basis sets. The frequencies of the stretching vibrations of the phosphate group calculated using semi-empirical functional B3LYP for all basis sets deviate significantly from the experimental values. The number of polarization functions on heavy atoms was shown to be a key factor for the calculation of vibrational frequencies of organophosphates. The importance of consideration of all the stable rotamers for a complete assignment of fundamental modes was shown.

scholarly journals Towards an accurate description of perovskite ferroelectrics: exchange and correlation effects

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Simuck F. Yuk ◽  
Krishna Chaitanya Pitike ◽  
Serge M. Nakhmanson ◽  
Markus Eisenbach ◽  
Ying Wai Li ◽  
...  
Keyword(s):  
Density Functional ◽  
General Purpose ◽  
Correlation Effects ◽  
Lattice Constants ◽  
Bulk Solids ◽  
Wide Range ◽  
Exchange Enhancement ◽  
Experimental Values ◽  
Similar Accuracy ◽  
Ferroelectric Oxides

Abstract Using the van der Waals density functional with C09 exchange (vdW-DF-C09), which has been applied to describing a wide range of dispersion-bound systems, we explore the physical properties of prototypical ABO 3 bulk ferroelectric oxides. Surprisingly, vdW-DF-C09 provides a superior description of experimental values for lattice constants, polarization and bulk moduli, exhibiting similar accuracy to the modified Perdew-Burke-Erzenhoff functional which was designed specifically for bulk solids (PBEsol). The relative performance of vdW-DF-C09 is strongly linked to the form of the exchange enhancement factor which, like PBEsol, tends to behave like the gradient expansion approximation for small reduced gradients. These results suggest the general-purpose nature of the class of vdW-DF functionals, with particular consequences for predicting material functionality across dense and sparse matter regimes.

scholarly journals Thermal Conductivities of Choline Chloride-Based Deep Eutectic Solvents and Their Mixtures with Water: Measurement and Estimation

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3816
Author(s):  
Taleb H. Ibrahim ◽  
Muhammad A. Sabri ◽  
Nabil Abdel Jabbar ◽  
Paul Nancarrow ◽  
Farouq S. Mjalli ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Choline Chloride ◽  
Deep Eutectic Solvents ◽  
Standard Uncertainty ◽  
Heat Transfer Fluids ◽  
Wide Range ◽  
Different Temperatures ◽  
Experimental Values ◽  
Water Measurement ◽  
Thermal Conductivities

The thermal conductivities of selected deep eutectic solvents (DESs) were determined using the modified transient plane source (MTPS) method over the temperature range from 295 K to 363 K at atmospheric pressure. The results were found to range from 0.198 W·m−1·K−1 to 0.250 W·m−1·K−1. Various empirical and thermodynamic correlations present in literature, including the group contribution method and mixing correlations, were used to model the thermal conductivities of these DES at different temperatures. The predictions of these correlations were compared and consolidated with the reported experimental values. In addition, the thermal conductivities of DES mixtures with water over a wide range of compositions at 298 K and atmospheric pressure were measured. The standard uncertainty in thermal conductivity was estimated to be less than ± 0.001 W·m−1·K−1 and ± 0.05 K in temperature. The results indicated that DES have significant potential for use as heat transfer fluids.

scholarly journals Automatic and Online Detection of Rotor Fault State

2018 ◽  
Vol 7 (1) ◽  
pp. 43 ◽  
Author(s):  
Ali Ouanas ◽  
Ammar Medoued ◽  
Salim Haddad ◽  
Mourad Mordjaoui ◽  
D. Sayad
Keyword(s):  
Induction Motor ◽  
Dimensional Space ◽  
Operating Conditions ◽  
Online Detection ◽  
K Nearest Neighbor ◽  
Simple Method ◽  
Important Place ◽  
Motor Test ◽  
Wide Range ◽  
Fault State

In this work, we propose a new and simple method to insure an online and automatic detection of faults that affect induction motor rotors. Induction motors now occupy an important place in the industrial environment and cover an extremely wide range of applications. They require a system installation that monitors the motor state to suit the operating conditions for a given application. The proposed method is based on the consideration of the spectrum of the single-phase stator current envelope as input of the detection algorithm. The characteristics related to the broken bar fault in the frequency domain extracted from the Hilbert Transform is used to estimate the fault severity for different load levels through classification tools. The frequency analysis of the envelope gives the frequency component and the associated amplitude which define the existence of the fault. The clustering of the indicator is chosen in a two-dimensional space by the fuzzy c mean clustering to find the center of each class. The distance criterion, the K-Nearest Neighbor (KNN) algorithm and the neural networks are used to determine the fault type. This method is validated on a 5.5-kW induction motor test bench.Article History: Received July 16th 2017; Received: October 5th 2017; Accepted: Januari 6th 2018; Available onlineHow to Cite This Article: Ouanas, A., Medoued, A., Haddad, S., Mordjaoui, M., and Sayad, D. (2017) Automatic and online Detection of Rotor Fault State. International Journal of Renewable Energy Development, 7(1), 43-52.http://dx.doi.org/10.14710/ijred.7.1.43-52

Notizen: The Dipole Moment Function of HF Molecule Using Morse Potential

1977 ◽  
Vol 32 (8) ◽  
pp. 897-898 ◽  
Author(s):  
Y. K. Chan ◽  
B. S. Rao
Keyword(s):  
Wave Equation ◽  
Dipole Moment ◽  
Potential Function ◽  
Electric Dipole ◽  
Morse Potential ◽  
Moment Function ◽  
Matrix Elements ◽  
The Matrix ◽  
Vibration Rotation ◽  
Experimental Values

Abstract The radial Schrödinger wave equation with Morse potential function is solved for HF molecule. The resulting vibration-rotation eigenfunctions are then used to compute the matrix elements of (r - re)n. These are combined with the experimental values of the electric dipole matrix elements to calculate the dipole moment coefficients, M 1 and M 2.

Simplified approach to confidence limited in radioimmunassay.

1980 ◽  
Vol 26 (6) ◽  
pp. 763-765 ◽  
Author(s):  
R C Baxter
Keyword(s):  
Quality Control ◽  
Mean Value ◽  
Confidence Limits ◽  
Simple Method ◽  
Response Variable ◽  
Simplified Approach ◽  
Quadratic Curve ◽  
Wide Range ◽  
Advanced Computing ◽  
Routine Quality Control

Abstract A simple method of calculating confidence limits for radioimmunoassay data is presented. The method involves the use of the within-assay variation in dose estimate of three routine quality-control specimens, measured in repeated assays, to estimate the confidence limits for results on unknown samples. Results for control specimens are combined by calculating the unique quadratic curve fitting a graph of within-assay standard deviation vs mean value for each control. This method requires no special data accumulation or advanced computing equipment. For cortisol, lutropin, and thyroxine radioimmunoassays, confidence limits calculated in this way have been compared with those calculated from the variance of the response variable “B/B0” in repeated standard curves. Both methods agree well with actual limits observed when plasma pools containing a wide range of hormone concentrations are assayed repeatedly.

scholarly journals A New Generalized Morse Potential Function for Calculating Cohesive Energy of Nanoparticles

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3323 ◽  
Author(s):  
Omar M. Aldossary ◽  
Anwar Al Rsheed
Keyword(s):  
Potential Function ◽  
Cohesive Energy ◽  
Morse Potential ◽  
Attractive Force ◽  
Repulsive Interaction ◽  
Additional Parameter ◽  
Generalized Potential ◽  
The Stability ◽  
Experimental Values ◽  
Generalized Morse Potential

A new generalized Morse potential function with an additional parameter m is proposed to calculate the cohesive energy of nanoparticles. The calculations showed that a generalized Morse potential function using different values for the m and α parameters can be used to predict experimental values for the cohesive energy of nanoparticles. Moreover, the enlargement of the attractive force in the generalized potential function plays an important role in describing the stability of the nanoparticles rather than the softening of the repulsive interaction in the cases when m > 1.

scholarly journals VLE of Carbon Dioxide-Loaded Aqueous Potassium Salt of L-Histidine Solutions as a Green Solvent for Carbon Dioxide Capture: Experimental Data and Modelling

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Afaf Syalsabila ◽  
Abdulhalim Shah Maulud ◽  
Humbul Suleman ◽  
Nik Abdul Hadi Md Nordin
Keyword(s):  
Carbon Dioxide ◽  
Potassium Salt ◽  
Carbon Dioxide Capture ◽  
Oxidative Degradation ◽  
Absorption Capacity ◽  
Similar Process ◽  
Process Conditions ◽  
Wide Range ◽  
Experimental Values ◽  
Biological Component

In this study, vapour-liquid equilibrium of CO2-loaded aqueous potassium salt of L-histidine was studied for a wide range of temperature (313.15–353.15 K), pressure (150–4000 kPa), and solvent concentrations (1–2.5 molar). The experimental results show that L-histidine has an excellent absorptive capacity for carbon dioxide. When compared to conventional solvent (monoethanolamine) and amino acid salt (potassium L-lysinate) at similar process conditions, L-histidine has superior absorption capacity. Moreover, modified Kent–Eisenberg model was used to correlate the VLE of the studied system with excellent agreement between the model and experimental values. The model exhibited an AARE% of 7.87%, which shows that it can satisfactorily predict carbon dioxide solubilities in aqueous potassium salt of L-histidine at other process conditions. Being a biological component in origin, almost negligibly volatile, and highly resistant to oxidative degradation, L-histidine offers certain operational advantages over other solvents used and has a promising potential for carbon dioxide capture.

The adhesion of metals to crystal faces

1963 ◽  
Vol 274 (1357) ◽  
pp. 267-273 ◽  
Keyword(s):  
Alkali Halide ◽  
Van Der Waals ◽  
Extended Period ◽  
Metal Films ◽  
Metal Substrate ◽  
Adhesion Mechanism ◽  
Glass Substrates ◽  
Van Der Waals Attraction ◽  
Experimental Values ◽  
Alkali Halide Crystals

Films of a number of metals have been deposited on the (100) faces of some alkali halide crystals. In each case the adhesion was measured over an extended period, and the adhesion was expressed as the shearing force required to remove the film. It was found that the adhesion was relatively poor and there was no variation in adhesion with time such as had been observed for many metal films on glass substrates. Various adhesion mechanism s were considered, but all the results could be explained adequately by van der Waals forces alone and a linear relation was shown to exist between the experimental values and the calculated van der Waals attraction for each metal-substrate pair.

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