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• Two configurations of Solar Water Tank (SWT), with a jacketed shell and a spiral-type heat exchangers are studied. • The effect of adding a propeller stirrer to the SWT is carried out. • The effect of operational parameters such as HTF flow and the stirring speed on the performance of the SWT/Ne-PCM tank are discussed. In the present work, an experimental assessment of the performance of a Solar Water Tank (SWT) integrated with Nano-enhanced Phase Change Material (Ne-PCM) and a Stirrer. Two configurations of SWT/Ne-PCMs, a spiral-type and a jacketed shell-type heat exchangers are designed and developed. These SWTs are integrated with the Nano-enhanced PCM within cylindrical capsules. A laboratory-scale experimental setup is conducted to examine the performance effect of the SWTs integrated with a propeller stirrer. In addition, an analysis of the effects of various process parameters including HTF flow rate and stirring speed was carried out. The results show that compared to the jacketed tank (without stirring), the completion time for the SWT/Ne-PCM charging and discharging processes (with a stirrer and a coil) is reduced by 12.5% and 23.51%, respectively. [ABSTRACT FROM AUTHOR]

• Density Functional Theory based study was performed for halide perovskite materials. • Copper and calcium were selected along with chlorine, bromine and iodine for this study. • Optical properties were studied, and direct energy band gap was found that could be tailored by changing the halide ions. • Thermal conductivity was studied in detail for thermoelectric application. The mechanical, electronic, optical, and thermoelectric analyses of CuCaX 3 (X = Cl, Br, I) have been done using DFT based TB-mBJ approach. The stability of CuCaX 3 (X = Cl, Br, I) has been confirmed from the enthalpy of formation; values for CuCaCl 3 , CuCaBr 3 , and CuCaI 3 are −1.07 eV, −1.55 eV, and −2.15 eV, respectively. The phonon spectra plot is also discussed, and the phonon dispersion analysis confirms that the CuCaX 3 systems are dynamically stable since no imaginary modes are observed. The modified Becke-Johnson exchange potential is used to evaluate the opto-electronic and thermo-electric properties. By replacing anions (Cl to I), the band gap of the studied material in the visible region has been tailored, from 2.9 eV to 2.65 eV, for renewable energy devices. In addition, various optical properties such as dielectric constant, refraction, absorption, optical conductivity, and optical loss factor have been analyzed for optoelectronic applications. With the replacement of anions (Cl to I), the peaks of maximum intensities shifted to lower energy to values of 7.2 eV, 6.2 eV and 5 eV for CuCaCl 3, CuCaBr 3 and CuCaI 3 respectively. Furthermore, the BoltzTrap code has been used to discuss thermal conductivity, power factor, Hall coefficient, specific capacitance and electron densities in detail for thermoelectric applications. The CuCaX 3 family of perovskites has been found to have bandgaps falling in the visible region for light-emitting diodes (LEDs). These also exhibit high thermal efficiency, making them potential multifunctional candidates for optoelectronic and energy harvesting applications. [ABSTRACT FROM AUTHOR]

In this paper, we investigate a new composite that consists of ferrites nanoparticles on porous silicon. Ferrites of cobalt nanoparticles (CoFe 2 O 4) were embedded using spin coating method into porous Silicon (PSi) which is prepared by electrochemical etching of p-type Si (1 0 0) wafers. Scanning electron microscopy (SEM) and X-Ray diffraction (Cu-Kα radiation) results has shown the presence of nanoparticles with crystallite sizes about 7–9 nm. The SEM Image CoFe 2 O 4 nanoparticles spin coated on p-type porous silicon shows that most of the particles are aggregated and exhibit a compact arrangement of the nanoparticles with roughly spherical shape. Nonetheless, X-Ray diffraction results have shown that the film have a good crystalline quality. For the optical properties of the composite, it will be studied using various techniques such as ellipsometry and Reflectance by a UV–VIS spectrophotometer. The reflectance study illustrates the ability of the nanoparticles dispersion to produce optical antireflection properties on the porous silicon. We also deduce that the reflectance of the nanoparticles dispersed on porous Si is higher than the reflectance of the nanoparticles dispersed on Si wafer; it is in fact due to the enormous number of nucleation sites in the case of porous Si. The optical parameters such the refractive index and the extinction coefficient were determined using the ellipsometry spectroscopy. [ABSTRACT FROM AUTHOR]

Lead-free halide perovskites have been investigated as promising materials for energy harvesting and thermoelectric device applications. The current article thoroughly explains the electronic behavior, stability, optical and thermoelectric characteristics of CdKF 3 and CdKCl 3 halide perovskite. For structural stability, the elastic constant and phonon dispersion of both halides are investigated. Additionally, thermodynamic stability is demonstrated by the investigation of formation energy (-2.45 to −1.89 eV). The ductile nature of both halides is confirmed by calculating the Poisson ratio, and their significance for the manufacturing of devices. The direct bandgap nature (2.65 eV and 0.9 eV) of both halides is observed through electronic band structures using mBJ-GGA, which has been employed to obtain more precise results for optoelectronic applications. Both halides show remarkable optoelectronic performance, with low reflectivity, high optical absorption, and conductivity. Thermal and electrical conductivity are also used to study the thermoelectric characteristics. Both halides show the figure of merit (ZT) near unity, ZT indices highlight their importance for thermoelectric devices. [ABSTRACT FROM AUTHOR]

• The electronic band structure of InP/InNPBi are investigated within the framework of BAC model. • Thermodynamic properties of the quantum gas are investigated in the presence of a quantizing magnetic field and a finite temperature. • The variation of the specific heat versus temperature for different effective masses at fixed magnetic fields are studied. • The effect of broadening parameter, doping level, and the effective mass on the thermodynamic properties of gas is discussed. The electronic band structure of InP/InNPBi has been theoretically investigated within the framework of the band anticrossing (BAC) model. The matched InP/InNPBi heterostructure has been proposed as an interface that confines electrons in a 2D sheet. The physical parameters of this structure are determined considering the BAC model and based on the self-consistent calculation of coupled Schrodinger-Poisson equations. Thermodynamic properties of the quantum gas of noninteracting electrons are investigated by calculating the chemical potential (μ), the magnetization (M), and the specific heat capacity (C v) in the presence of a quantizing magnetic field and a finite temperature. The effect of characteristic parameters of the structure (broadening parameter, doping level, and effective mass) on the thermodynamic properties of gas is discussed. More interest is focused on the study of the evolution of C v as a function of temperature for different estimated effective masses of InNPBi material. [ABSTRACT FROM AUTHOR]