Search

Adequate and accurate models of thermal power plants (TPP) and hydropower plants (HPP) are of great importance for the optimal economic functioning of electric power systems. The extracted models have a direct impact on economic dispatch calculations. In this research, a modified optimization algorithm called an improved gradient-based optimizer (IGBO) is deployed for the optimal extraction of TPP and HPP input-output parameters. Firstly, the IGBO is tested for use with well-known benchmark functions and shows outstanding performance over the original GBO and other competitive algorithms. For the input-output parameters extraction of TPP and HPP, the sum of the absolute error (SAE) is utilized as a fitness function to be minimized. Secondly, nine models of TPP and HPP are employed for parameter identification using IGBO. Simulation outcomes prove the capability of IGBO to accurately extract input-output parameters of TPP and HPP. Moreover, the convergence characteristics of IGBO are remarkable among investigated optimization algorithms. [ABSTRACT FROM AUTHOR]

Nowadays, multi-criteria decision-making (MCDM) methods are used widely in many fields of research and applications. Many studies have shown that MCDM approaches are effective in determining the optimal solution to a variety of symmetrical and asymmetrical problems with numerous parameters. This article investigates a novel approach using multi criteria decision making (MCDM) to optimize the parameters of static var compensator (SVC) and power system stabilizers (PSS). The proposed technique integrates similarity membership function reduction algorithm (SMFRA), removal effects of criteria (REC) and combined compromise solution (CoCoSo). In the first stage, (SMFRA) is employed to select the most dominant controller parameters in the optimization process. Secondly, the weights of the reduced parameters are computed based on (REC). Finally, (CoCoSo) method searches for the optimal setting parameters. A detailed sensitivity analysis is presented to evaluate the obtained results. It is found that the suggested integrated technique is time saving, easily implemented and of low computation burden, which can successfully be implemented to solve a wide range of issues, both comparable and dissimilar. [ABSTRACT FROM AUTHOR]

The primary focus of this study is the influence of antimony oxide on the radiation-attenuating, optical, and physical characteristics of the (65-x) P2O5-15Li2O-15ZnO-5Bi2O3-xSb2O3 glass system. The glass samples show a rapid increase in molar volume and density as Sb2O3 replaces for P2O5. The effectiveness of the glasses to block beams of gamma as well as neutron radiation was examined. Utilizing the newly developed Phy-X/PSD software and X-Com, radiation investigations were carried out and compared with MNCP simulation. The following parameters were examined: fast neutron removal cross section, effective atomic number, half value layer, tenth value layer, linear attenuation coefficient, mass attenuation coefficient, and effective electron density to assess the radiation-shielding capabilities of the current samples. The results showed that the amount of antimony oxide had a substantial impact on the gamma-ray shielding capabilities. For example, for Sb-0.0, Sb-1.0, Sb-2.0, Sb-3.0, and Sb-4.0, the resulting mass attenuation coefficient Gμm values are 0.591, 0.639, 0.685, 0.731, and 0.776 cm2/g at 0.08MeV. Additionally, the acquired data was compared to traditional radiation shields. It is considered that the current glasses will have a possibility as radiation-resistant materials because of their capacity to adjust the antimony oxide quantity to match the intended usage. The absorption spectrum's edge was shifted to higher wavelengths and the gaps in the optical energy (EOPT) decreased as the amount of antimony grew, according to UV–visible-NIR studies. The corresponding indirect (EOPT) decreased from 3.789eV to 2.338eV, while the direct (EOPT) declined from 3.962eV to 2.895eV. It has been demonstrated that non-bridging oxygens, or NBOs, are the cause of the decline in EOPT. As the amount of Sb3+ ions increase in the glass structure, there is a reduction in both the Metallization Criterion (M) and the nonlinear optical susceptibility (χ (3)). The optically refractive index (n0), molar refraction (Rmolar), and nonlinear coefficient of refraction (n2) all rise with increasing Sb3+ concentration. [ABSTRACT FROM AUTHOR]

The effect of vanadium oxide (V2O5) on the structural, dielectric, and shielding features of borate-lead-fluoride glasses was investigated. The density of the glass network increased steadily from 3.18 to 3.28 g.cm−3 as the vanadium content increased from 0.0 to 10 mol%. The evolution of functional groups and units such as non-bridging BO3, and bridging BO4, in our newly developed glasses was exposed by FTIR analysis. Since the fraction of bridging units BO4 increases when V2O5 is added up to 2 mol%. This indicates that the conversion of BO3 groups into BO4 groups is facilitated by V2O5. However, at higher concentrations of V2O5 (> 2 mol%), a reversal reaction occurs wherein the BO3 unit fraction increases and the BO4 unit fraction starts to decrease. All the glasses loaded with different amounts of V2O5 mol% had a sharp decline in dielectric constant with increasing frequency over the low frequency interval. As the V2O5 level grew up to 2 mol%, the dielectric constant value was marginally reduced and then increased for higher concentrations. All of the glasses under examination displayed different relaxation peaks in the range of 100 Hz to 20 kHz on their measured loss tangent (tan δ), but vanadium doping caused them to shift to higher frequencies. At 0.015 MeV, the maximum MAC values for the V-0.0 to V-10.0 samples were found to be 29.205 cm2/g to 30.082 cm2/g. In terms of radiation shielding, the V-10.0 sample exhibited the highest values of mass (MAC) and linear (LAC) attenuation coefficients, while the same sample possessed the lowest values of half value layer and mean free path among all investigated glasses. Therefore, the investigate glass can be used in several optical and radiation shielding applications. [ABSTRACT FROM AUTHOR]

Five samples of barium borosilicate reinforced with various concentrations of CdO with the nominal compositions (43.5 − x)B2O3 + 0.5Sm2O3 + 12SiO2 + 25BaF2 + 19Na2O + xCdO and substitution ratios x = 0, 2.5, 5, 7.5, and 10 mol% were synthesized using the melt quenching method. The impact of B2O3/CdO on structure, physical parameters, and optical characteristics was investigated. Gamma-ray shielding capacity was evaluated theoretically using Phy-X/PSD software. The amorphous nature of prepared glass samples was verified by XRD measurements. The densities (Ds) enhanced from 2.81 to 3.41 g/cm3, while molar volume (Vm) declined from 33.80 to 29.51 cm3/mol. The UV absorption spectra displayed many bands due to transitions from the ground state (6H5/2) to the excited states of Sm3+ ions. Values of optical band gaps (Eg) declined with increasing CdO concentration, through the direct transition ranged from 2.80 to 2.64 eV, while for the indirect transition going from 2.65 to 2.53 eV. Urbach energy (EU) values varied from 0.1319 to 0.1078 eV. Cd10 sample possessed the maximum and highest mass (MAC) attenuation coefficient, whereas the Cd0 sample possessed the lowest values From the perspective of the half value layer (HVL), Cd10 sample presents the best option for radiation attenuation applications out of all the synthesized samples, and the samples are ranked as follows: Cd10 < Cd7.5 < Cd5 < Cd2.5 < Cd0. Effective atomic number (Zeff) has the same trend of MAC. Results confirmed that the suggested Cdx samples can be applied for optical and radiation shielding uses. [ABSTRACT FROM AUTHOR]

An analysis of the effects of europium oxide (Eu2O3) on the shielding, dielectric, and structural properties of zinc lithium borate glasses was carried out. A rise in the amount of Eu2O3 in glasses from 0.0 to 1.0 mol% results in an improvement in density from 3.086 to 3.2176 g cm−3. FTIR analyses of our recently developed glasses revealed the production of functional groups and units, including bridging BO4 and non-bridging BO3. Bridging BO4 rose at low concentrations of europium oxide and returning to BO3 at high concentrations of europium oxide. The dielectric constant of all the glasses loaded with various ratios of Eu2O3 mol% sharply decreased as frequency rose in the low-frequency range. As the Eu2O3 level increased to 0.25 mol%, the dielectric constant value first decreased, suggesting an improvement in BO4 and then improved at increasing concentrations. For each glass that was examined, the indicated tan δ showed a relaxation peak at approximately 5 kHz. The lowest tan δ was found at a level of 0.25 mol% Eu2O3. The specimen of glass altered with 0.25 Eu is a desirable choice for packing materials because of its smallest tan δ and dielectric constant. The gamma-ray exposure buildup and energy absorption factors parameters of that oxide glass system in energy region of 0.015–15 MeV up to depths of penetration of 40 mfp have been calculated by using Photon Shielding and Dosimetry (PSD) software. It has been demonstrated that Zeq values vary on photon energy. [ABSTRACT FROM AUTHOR]

The influence of nickel-oxide (NiO) addition on the structural, optical, physical properties, and dielectric spectroscopy of lead-borated glass blocks of the chemical form: (70-x)B2O3-25Na2O-5PbO-xNiO: x = 0 (Ni-0.0)-2.5 (Ni-2.5) molar percentage was tested experimentally using various methods. X-ray diffraction measurements confirmed the amorphous character of prepared Ni-glasses. Density increased gradually from 2.5981 to 2.7568 g cm−3, whereas molar-volume declined from 29.0131 to 28.0202 cm3 mol−1 as Ni2+ ions-contenting samples improved from 0.0 to 2.5 mol% in glasses network. In the absorption UV-region, optical-gap energy changed between 2.94 and 2.48 eV. In absorption within Vis-region, the intensity of the absorbed band enhanced gradually with red-shift in their positions as Ni2+ ions content increased. In the absorption NIR-region, an increase in the IR absorption bands was observed and confirmed the enhanced heat-absorption capacity of the investigated glasses as their NiO content increased. Dielectric spectroscopy at frequencies ranging from 50 Hz to 5 MHz of (70-x)B2O3-25Na2O-5PbO-xNiO: x = 0, 0.5, 1.0, 1.5, 2.0, and 2.5 mol% glasses are carried out to determine the impact of nickel doping on dielectric spectroscopy items. Nickel doping gradually increased the dielectric constant. At high frequencies, the transport rate among nearby conductive sites is increased while the shifting length of the charges is greatly reduced which leads to higher conductivity. [ABSTRACT FROM AUTHOR]

The role of the [Na2O]/[CuO] ratio in two glass groups with a chemical formula of (50 − y/2)Na2O–yCuO–(50 − y/2) P2O5 (y = 0.0–40 mol%) coded as Line I and (50 − y)Na2O–yCuO–50P2O5 (y = 0.0–50 mol%) coded as Line II on physical and gamma-ray attenuation properties have been deeply investigated. The density (ρ) varied from 2.471 to 3.262 g/cm3 and from 2.471 to 3.113 g/cm3 for Line I and Line II glasses, respectively. The molar volume (Vm) values varied from 41.280 to 28.526 cm3/mol and from 41.280 to 35.609 cm3/mol for Line I and Line II glasses, respectively. The oxygen molar volume (OMV) reduced from 13.761 to12.972 cm3/mol and from 13.761 to 11.873 cm3/mol, while the oxygen packing density (OPD) improved from 72.674 to 77.124 and from 72.674 to 84.253 g.atom/l for Line I and Line II glasses. The mass and linear attenuation coefficients (MAC and LAC) values corresponding to the Line II glass is slightly lower than their counterpart of the Line I. The effective atomic numbers (Zeff) and electron density (Neff) for glasses in Line I was lower than that for those in Line II. Exposure (EBF) and energy absorption (EABF) buildup factors have the same trend in both glass groups. The findings support the capability to utilize the examined glasses as radiation shielding materials. [ABSTRACT FROM AUTHOR]

We have successfully used a quick melt-quench procedure and casting approach to make an array novel glasses loaded with lanthanum oxide employing phosphate, lithium, bismuth, and zinc. As lanthanum concentration grew from 0 to 4 mol%, the densities of the samples under investigation increased from 2.94613 to 3.2182 g/cm3. Phy-x/PSD software was used to determine some critical gamma radiation attenuation parameters across a broad energy range (0.015–15 MeV), specifically effective electron density, equivalent atomic number, and build-up factor coefficients for the glasses under investigation. The La-4 glass sample containing 4 mol% of lanthanum proved to be more successful in the penetration of charged particle radiation, based on the results of this investigation. Following the band edge, all samples showed excellent transmission range and good transparency in the visible and near-infrared wavelength spanning 380 to 900 nm. The refractive index (n), the extinction or attenuation coefficient, the dielectric constant (ε1\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\varepsilon_{1}$$\end{document}, ε2), VELF, and optical reflectance were enhanced with increasing the quantity of La3+ ions in the glass structure. The produced samples’ Young’s modulus increased from 45.529 to 49.110 GPa, their bulk modulus increased from 20.622 to 23.915 GPa, and their shear modulus increased from 20.109 to 21.210 GPa when La2O3 was substituted for P2O5 from 0 to 4 mol%. Also, micro-hardness dropped from 4.933 to 4.839 GPa, and Poisson’s ratio increased from 0.132 to 0.158. [ABSTRACT FROM AUTHOR]

Instability of an adaptive flux observer (AFO) in the regenerating mode at low frequencies is a great challenge of sensorless induction motor (SIM) drives. Zero observer feedback gains (OFGs) in the regenerating mode at low frequencies are the main reasons for moving the dominant zero of the speed estimators to the unstable region. OFGs should be appropriately selected to transfer the unstable dominant zero to the stable region. In this paper, genetic algorithm (GA) and particle swarm optimization (PSO) techniques were used to design the OFGs for a stable observer. A fair comparison of the dominant zero location between the two approaches using the optimized OFGs is presented under parameter deviation. Analytical results and the design procedure of the OFGs using the two approaches are presented under deviations of stator resistance and mutual inductance to guarantee a stable dominant zero in the regenerating mode of IM. The dominant zeros obtained by PSO had a superior location to that obtained by GA for both stator resistance and mutual inductance deviations. It was observed that one of the gains had an almost constant value over a wide range of parameter deviations. However, the value of the other gain was dependent on the deviation of machine parameters. The advantage of using PSO over GA is that the relation between the gain and parameter deviation can be represented by a deterministic and mostly linear relationship. Simulation and experimental work of the SIM drive are presented and evaluated under the optimized OFGs. [ABSTRACT FROM AUTHOR]