Synthesis and Performance Elucidation of Ternary O3-Na0.8Fe0.4Mn0.3Co0.2O2 Layered Positive Electrode for Sodium Ion Batteries

We report here a combination of transition metal-based ternary sodium magnate layered cathodes with the compositions of Na0.8Fe0.4Mn0.3Co0.2O2, Na0.8Fe0.4Mn0.3Ni0.2O2, Na0.8Fe0.4Mn0.3V0.2O2, Na0.8Fe0.4Mn0.3Ti0.2O2, in order to elucidate the precise metal contents for the superb performing positive electrode. Based on their stoichiometry, the transition metal combination of Na0.8Fe0.4Mn0.3Co0.2O2, O3-type crystal structure with R3m space group possess superior electrochemical behavior under the test of sodium-ion battery. When the charge-discharge capacities in the range of 2.0-4.2 V at 0.1 C are measured, it shows the comparatively higher performance of the first and second charge capacities of 162 mAhg-1, 170 mAhg-1 and discharge capacities of 157 mAhg-1, 154 mAhg-1, respectively. Moreover, it was remarkable to observe that the increasing/decreasing Co constituent substantially affects the performance and stability, but using the ternary combination in cathodes, a substantial reduction of Jahn-Teller distortion and increased biphasic characteristics were observed. The as-synthesized samples were characterized by FE-SEM, XRD, charge-discharge curve, EIS and cyclic voltammograms.

Role of MXenes/Polyaniline Nanocomposites in Fabricating Innovative Supercapacitor Technology

Versatile and exclusive electronic, optical, physicochemical, electrochemical and mechanical features of both conducting polymers and MXenes have stimulated global scientists to take serious impetuses in designing innovative high-performance energy storage systems with these materials, for resolving the growing needs for auto-powering mechanically flexible and wearable electronics for all essential technological fields. However, both the materials have experienced some serious practical limitations, which have driven the scientific community to look for necessary modifications in the form of MXenes/PANI nanocomposites with suitable compositions that would essentially restore their representative characteristics but successfully suppress their functional drawbacks concurrently and considerably. Accordingly, in the present overview, the different strategies of fabrication of MXenes/PANI nanocomposites for advanced supercapacitors with special reference to the necessary morphological modifications brought about by synthetic improvisations that resulted in superior capacitive, electronic charge transport as well as structural properties have also been recognized and compared. Such analysis would purposefully assist in adjusting the integral mechanical and electrochemical responses for scheming smarter and highly flexible microelectronics soon.

Single-Step Green Synthesis of Iron Nanoparticles in the Aqueous Phase for Catalytic Application in Degradation of Malachite Green

The goal of the research was to devise a simple and environment-friendly approach to synthesize iron nanoparticles (FeNPs) and evaluate the catalytic activity of biosynthesized FeNPs for the degradation of the cationic dye Malachite Green (MG) in the presence of Peroxomonosulphate (PMS). Different instrumental approaches were used to characterize green produced FeNPs, and the results show that the NPs are spherical and 48 nm in size. Increasing the concentrations of nanoparticles (0.5 × 10-8 - 2.0 × 10-8 mol/dm3), Peroxomonosulphate (1.0 × 10-4 - 5.0 × 10-4 mol/dm3), dye (1.0 × 10-5 - 5.0 × 10-5 mol/dm3), pH (5), and high temperature (25-35 °C) enhanced the degradation kinetics of Pseudo-first-order kinetics were used to describe the degradation of MG in the FeNPs/PMS system, and activation parameters were derived. The maximum MG degrading efficiency for the FeNPs/PMS system was 88% in 60 minutes under optimum reaction conditions. The structure of intermediates formed by MG degradation by FeNPs/PMS was determined using UV-vis spectrum analysis. The application of synthesized FeNPs to improve Peroxomonosulphate oxidation potential for MG degradation is a unique, efficient, promising, and eco-friendly technology because it does not require any expensive reagents.

Synthesis of O3-Na0.8Fe0.6Mn0.3O2 Positive Electrode and Its Application to Sodium Ion Batteries

Herein, we report precise variation of Fe and Mn constituent in the sodium magnate layered cathodes with the compositions of Na0.8Fe0.4Mn0.5O2, Na0.8Fe0.5Mn0.4O2, Na0.8Fe0.6Mn0.3O2, Na0.8Fe0.6Mn0.4O2, Na0.8Fe0.7Mn0.4O2, Na0.9Fe0.6Mn0.3O2 in order to attain a high performing cathode. Based on this transition metal stoichiometry, an interesting sodium magnate combination of Na0.8Fe0.6Mn0.3O2, with O3-type crystal phase, possess R3m space group along with the superior electrochemical behavior is obtained. On charge-discharge capacities in the range of 2.0-3.8 V at 0.1 C, it shows the comparatively higher performance of the first and the second charge capacity of 115 and 180 mAhg-1 and discharge capacity of 184 and 181 mAhg-1, respectively. The best sample was then compared with the closely related Na0.8Fe0.6Mn0.4O2, Na0.9Fe0.6Mn0.3O2 combination in terms of valence ratio and influence of excess sodium for the structure robustness, stability along with purity. The best sample with the composition Na0.8Fe0.6Mn0.3O2 does not show detectable impure phase while Na0.8Fe0.6Mn0.4O2 and Na0.9Fe0.6Mn0.3O2 shows a tendency of P-type (Cmca space group) behavior with 30.8% and 32.8%, respectively. The enhancement of iron constituent increases not only the performances but also the stabilization of sodium vacancy ordering and substitution of Mn with a substantial reduction of Jahn-Teller distortion, mounting biphasic characteristics and high peak intensity of 41.5 °.

Kinetic Description of Propagation of Quasiparticles Fluxes in Solid-state Structure

Within the framework of the kinetic theory, the interaction of systems of quasiparticles and the exchange of quasiparticles of different types between layers of a plane-parallel solid structure are taken into account. The reasons influencing the propagation of differential fluxes of quasiparticles near each boundary of the structure are indicated. These include not only the appearance of a force field, in particular, electric е∇φ(х) and thermal ∇Т(х), fields near the boundary in equilibrium and its modification when equilibrium is disturbed, but also a change in the coordinate and angular dependence of the relaxation length of fluxes le(x, k, Ω) in the same region. Some modification of the distribution of characteristic thermodynamic quantities in the inhomogeneous region of the layer in comparison with the homogeneous layer also affects the propagation of fluxes. The necessity of a self-consistent solution of the kinetic boundary value problem of the joint propagation of differential fluxes of quasiparticles-a system of equations and integral boundary conditions-is substantiated. Near the boundary and in another inhomogeneous region of the layer thickness, as well as in the thin layer as a whole, in quasiparticles systems, it is proposed to use a specific coordinate distribution of the flux density of thermodynamic quantities over the structure thickness, which is mutually self-consistent with the propagation of the corresponding quasiparticles fluxes. The main conclusion of this work: when developing modern multilayer solid-state structures, especially with thin layers, it is necessary to use the kinetic theory, which adequately takes into account the physical picture that occurs not only in homogeneous and inhomogeneous regions of the thickness of each layer, but also at all boundaries of the structure.

Environmental and Economic Impact of Employing Solar Chimney and Photovoltaic Cells in Buildings with Various Climates

In this research, Solar Chimney (SC) as a passive system in the building, is used to provide thermal comfort and reduction of energy consumption. The operation of SC will have different effects in different climates. Investigating this issue can make it possible to use this system in places where its operation is more efficient in terms of thermal comfort and economic issues. EnergyPlus was applied to model a house with SC. Potential of cooling and heating generated by SC was investigated in Humid (Babol) and Semi-arid (Tehran) climates. The result shows that in Babol, SC saves approximately 21% in cooling load and 16% in heating load consumption. On the other hand, in Tehran, using SC can save 35% in cooling load and 20% in heating load consumption. For both humid and semi-humid climates, Summer-SC (ventilation mode) performs better than Winter-SC (heating mode). In continue, for each city, the cost of saving electricity consumption by SC was spent on the purchase and installation of photovoltaic cells (PV). According to calculations, SC and PV systems annually produce 4717 kWh of clean energy in Babol and 6965 kWh in Tehran. In addition to producing clean energy, despite the low cost of grid electricity in Iran, employing these systems in each house, annually reduces the cost of electricity consumption by $ 8 and $ 14, respectively, in the cities of Babol and Tehran. Of course, this amount would be considerable for all the houses in a city.

A Study of Microstructural Models of Li-doped ZnO Ceramic for Piezoelectric Application

Structural and microstructural properties of Zn1-xLixO (0.00 ≤x≤ 0.50) ceramics were carried out using X-ray Diffraction (XRD) showed that the samples were polycrystalline with hexagonal wurtzite structure. The average crystallite size was estimated using three models, all of which showed decrement with increased lithium-doping. The crystallite size increased systematically, with the largest value being 200 nm in the Li-doped ZnO in x=0.3. However, microstrain was fairly constant for all doped samples with a value of ~0.006, the value for the pristine being 0.001. Of the three models, the comparison showed that the Scherer model had the smallest crystallite size due to the neglect of strain, whereas the W-H model had the largest in the doped samples, with crystallite size ~200 nm, but with subsequent decrease observed which is attributed to the assumption of isotropy in the model. The c/a ratio indicated a consistent hexagonal structure despite lithium-doping. Energy Dispersive Spectroscopy (EDS) showed that all the nominal elements compositions were present. A decrease in grain size with the increase in lithium-doping was observed with the lowest grain size (0.2 μm) observed in x=0.5, thus making it the specimen with the highest potential for piezoelectric application.

Effect of Synthesis Method on the Catalytic Performance of Ca-Mg-Al Mixed Metal Oxide Nanocatalyst for Biodiesel Production from Waste Cooking Oil

The synthesized nanomaterials by two different methods were used as a catalyst in the transesterification of waste cooking oil to produce biodiesel. For both environmental and economic reasons, it is beneficial to produce biodiesel from waste cooking oils. It is desirable to help solve waste oil disposal by utilizing its oils as an inexpensive starting material in biodiesel synthesis. The structure, morphology, and surface properties of resulting nanocatalysts were characterized by X-ray Fluorescence Spectroscopy (XRF), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Energy Dispersive X-ray Spectroscopy (EDX) and N2 adsorption-desorption isotherms. The synthesized nanocatalysts' efficiency in the production of biodiesel was studied by Gas Chromatography (GC) as well as leaching amounts of surface active components of each catalyst investigated by the EDX technique. The reactions were performed at 65°C using a 9:1 methanol to oil ratio for 3 h. The results indicate that the impregnated mixed metal oxide catalyst ( Ca-MgAl) shows a higher surface area and better mechanical strength than the totally co-precipitated mixed metal oxide catalyst (CaMgAl(O)). Although both of the fully co-precipitated and impregnated catalysts represented about 90% of fatty acid methyl esters (FAME) yield the leaching of active calcium component was significantly reduced from 45.8% in precipitated CaMgAl(O) to 8% for the impregnated Ca-MgAl catalyst. This improved structure represents the advantage of the impregnation technique to co-precipitation procedure for fabrication of robust nanostructures.

Characterization of Rice Husk and Coconut Shell Briquette as an Alternative Solid Fuel

The physical properties of briquettes made from rice husk and coconut shell in different ratios were evaluated based on their thermo-physical properties. The calculated calorific values of the rice husk and coconuts hell are 16.51 MJ/kg and 18.60 MJ/kg, with densities of 1.50 g/cm3 and 3.00 g/cm3, respectively. Coconut shell has lower moisture and ash content of 10% and 26%, respectively, before briquetting. Comparisons of the experimental and calculated calorific values of the briquettes (17 to 21 MJ/kg) showed that they are in agreement with those of the American Standard of Testing Materials (ASTM) and those reported in the literature. The results further showed that the calorific values of the five briquette ratios were not a function of their moisture and ash contents, rather their total carbon contents. The briquette at the ratio 90:10 of rice husk to coconut shell has the highest calorific value and implies that it has more heating advantages and will therefore be suitable as an alternative solid fuel.

Modelling and Parameter Extraction of PV Cell Using Single-Diode Model

In this work, numerical solution of nonlinear equations using Newton Raphson method (NRM) and a modified Newton-Raphson Method (MNRM) are utilized to solve and find the real roots of a nonlinear equation based on a single-diode PV cell. The proposed methods to solve nonlinear examples and obtain results with various values of a load resistance have been examined. The purpose of this paper is to obtain the results of solar cell parameters using two mathematical models with the comparison between them. The obtained results showed the proposed method (MNRM) is a powerful tool, sufficient way to solve this model with a least iterations.