Single Phase Research Articles

Study of structural and spectroscopic properties of Dy3+ ions doped potassium magnesium molybdate single phase phosphor for white lighting applications

Study of structural and spectroscopic properties of Dy3+ ions doped potassium magnesium molybdate single phase phosphor for white lighting applications

Viability and Antibacterial Properties of Ba2-x AgxFeMoO6(x=0.0, 0.05) Double Perovskite Oxides

Double perovskite Ba2FeMoO6 (BFMO) and doped with Ag ions were synthesized via the sol-gel method. The structural and antibacterial properties and viability of the samples were systematically investigated. The results of the Rietveld refinement indicated that both samples exhibited a single phase with cubic structure and space group Fm-3m. The substitution of Ag ions led to an increase in the unit cell and lattice parameters of BFMO, resulting in a change in the sample's morphology. The direct band gap (∼2eV) was measured for samples by Diffuse Reflectance Spectroscopy (DRS). Antibacterial activity of the Ba2FeMoO6 and Ba1.95Ag0.05FeMoO6 samples was assessed on the Gram-positive bacteria (Staphylococcus aureus) and the Gram-negative bacteria (Escherichia coli) using the spread plate method. The results showed that the samples were effective against Staphylococcus aureus but not against Escherichia coli. The sample doped with Ag ions showed a higher antibacterial effect than the pristine sample. An MTT assay of the normal fibroblast cell line treated with an Ag-doped sample showed a higher percentage of viability.

Phase-selective growth of κ- vs β-Ga2O3 and (InxGa1−x)2O3 by In-mediated metal exchange catalysis in plasma-assisted molecular beam epitaxy

Its large intrinsic polarization makes the metastable κ-Ga2O3 polymorph appealing for multiple applications, and the In-incorporation into both κ and β-Ga2O3 allows us to engineer their bandgap on the low-end side. In this work, we provide practical guidelines to grow thin films of single phase κ-, β-Ga2O3 as well as their (InxGa1−x)2O3 alloys up to x = 0.14 and x = 0.17, respectively, using In-mediated metal exchange catalysis in plasma-assisted molecular beam epitaxy (MEXCAT-MBE). The role of substrate temperature, oxidizing power, growth rate, and choice of substrate on phase formation and In-incorporation is investigated. As a result, the κ phase can be stabilized in a narrow deposition window irrespective of the choice of substrate [(i) α-Al2O3 (0001), (ii) 20 nm of (2̄01) β-Ga2O3 on α-Al2O3 (0001), and (iii) (2̄01) β-Ga2O3 single crystal]. Low growth rates/metal fluxes as well as growth temperatures above 700 °C tend to stabilize the β-phase independently. Lower growth temperatures and/or O-richer deposition atmospheres allow to increase the In-incorporation in both polymorphs. Finally, we also demonstrate the possibility to grow (2̄01) β-Ga2O3 on top of α-Al2O3 (0001) at temperatures at least 100 °C above those achievable with conventional non-catalyzed MBE, opening the road for better crystal quality in heteroepitaxy.

Correlated barrier hopping transport and non-Debye type dielectric relaxation in Zn2V2O7 pyrovanadate

Herein, the Zn2V2O7 electro-ceramic pyrovanadate was synthesized via a conventional solid-state reaction technique and calcined at 700 °C. The single phase formation of Zn2V2O7 pyrovanadate crystallized in the monoclinic structure with C12/c1 space group was confirmed by X-ray diffraction (XRD). The XRD powder diffraction profile was analyzed by Rietveld refinement to investigate the structural details of the compound. The complex impedance analysis was carried out in the frequency domain of 83−2×106 Hz over a temperature range of 453–613 K to study the electrical charge conduction and dielectric relaxation mechanism in the material which revealed the presence of the distribution of relaxation times with thermal charge activation. Depressed semicircles in the Nyquist plots were modeled by an equivalent circuit with configuration (RGCG)(RGBQGB) which resolved the contributions of grains and grain boundaries towards the transport properties of the material. The electrical conductivity spectra followed Jonscher's power law behavior and the temperature variation of frequency exponent suggested correlated barrier hopping (CBH) as the governing transport mechanism in the Zn2V2O7 pyrovanadate system. The comparison between scaling behaviors of imaginary parts of impedance and modulus advocated the temperature-independent nature of relaxation time distribution. The imaginary electrical modulus spectra were reproduced by the Kohlrausch, Williams, and Watt formulism, and the fitted parameters confirmed the non-Debye type nature of the dielectric relaxation. Further, the Haveriliak-Negami function was employed to investigate the dielectric response of the material which was found to be consistent with impedance, conductivity, and modulus analyses. The frequency dispersion of the tangent loss verified that the hopping mechanism was thermally activated.

Evading intermediate temperature embrittlement of FeCoCrNiMn high entropy alloy via N-doping

High entropy alloys (HEAs) exhibit high strength and excellent ductility at both room and low temperatures. The loss of ductility with increasing the tensile temperature above room temperature has been widely observed in single phase face-centred cubic structured HEAs. In this work, a N and Si doped FeCoCrNiMn-(N,Si) HEA with preexisting nano-sized Cr2N particles was fabricated by laser powder bed fusion (LPBF) and subsequent cold-rolling and annealing treatment. Tensile testing was conducted on the alloy at 298 K, 573 K, 773 K, 873 K, and 973 K, respectively. It has been shown that the FeCoCrNiMn-(N,Si) alloy with preexisting Cr2N phase exhibits a steady ductility with increasing the tensile temperature. The intermediate temperature embrittlement is evaded in the FeCoCrNiMn-(N,Si) alloy via N-doping. The widely reported loss of ductility with increasing deformation temperature was avoided in present FeCoCrNiMn-(N,Si) HEA by shifting fast segregation of element Cr from GBs into preexisting Cr2N phase due to the high affinity between N and Cr elements, leading to the increases in the content and size of Cr2N particles after high temperature deformation.

Observer-based single phase robustness load frequency sliding mode controller for multi-area interconnected power systems

Observer-based single phase robustness load frequency sliding mode controller for multi-area interconnected power systems

Microstructural evaluation and optimization of wear behaviour of vacuum arc melted AlFeCrNiSi high entropy alloy

High-entropy alloys (HEA) are equiatomic, multi-element systems that, while having several elements with various crystal geometries to form a single phase. In this study, a novel equiatomic AlFeCrNiSi HEA is prepared using the vacuum arc melting process. The resulting microstructure featured dendritic and inter-dendritic structures with formations of intermetallic compounds such as Al₃Fe₂Si, NiAl, and AlCrNi phases. EDS analysis confirmed the presence of alloying elements and EBSD analysis revealed refined grains with an average size of 1 ± 0.15 µm size. Pin-on-Disc wear test with varying test parameters is conducted to optimize the wear parameters. Signal-to-noise ratio and analysis of variance identified the most significant wear parameters, with load being the most influential, followed by sliding distance and velocity. The wear rate is minimum at the lowest conditions of applied load, sliding distance, and sliding velocity. The improved microhardness also contributed to the improved wear resistance of the cast alloy. The subsequent worn morphology revealed the formation of grooves, microcracks, and oxide layers on the worn surface.

Stress increase by nanoscale hcp precipitates in HfNbTaTiZr high entropy alloys

HfNbTaTiZr high entropy alloys show a stress increase around 873 K, especially in the single crystals. At 873 K, the bcc single phase is decomposed into the bcc1 and bcc2 phases due to spinodal decomposition with composition modulation along <100> direction. The bcc1 phase has Zr- and Hf-rich composition, while Nb and Ta are enriched in the bcc2 phase. Next, the hcp phase is precipitated along the bcc1 phase. As a result, the hcp phase is aligned parallel to {100} plane of the bcc phase. The fine hcp phase acts as a strong barrier to the dislocation motion, resulting in the stress increase at 873 K.

Perceived Parenting Styles, Emotional Intelligence and Conflict Resolution Styles among Young Adults

Purpose: Parenting styles greatly influence the development of emotional intelligence and conflict resolution styles among young adults since the very early years of their lives. The understanding how parenting styles and emotional intelligence impact conflict resolution styles of young adults has become progressively urgent. The existing study purposes to inspect the relationship between perceived parenting styles, emotional intelligence, and conflict resolution styles among young adults. The practical implication of this research will provide the future generations in better upbringing of their children that possess high levels of emotional intelligence. Methodology: The study was carried out in a single phase. The study was quantitative, and it was conducted to assess the perceived parenting styles by young adults including assessing their emotional intelligence and identifying their conflict resolution style. The sample of the study was 280 (M=140, F=140) recruited from different universities in Islamabad, Pakistan. Three scales were used for assessment: The Perceived Parenting Styles Scale (PPSC), The Schutte Self Report Emotional Intelligence Test (SSEIT) and the Conflict Resolution Styles Inventory (CRSI). Findings: The authoritative parenting style positively correlated with emotional intelligence (r = .47, p &lt; .01) and positive problem-solving (r = .17, p &lt; .01), while negatively relating to conflict engagement (r = -.31, p &lt; .01) and self-protection (r = -.26, p &lt; .01). In contrast, authoritarian and permissive styles were negatively related to emotional intelligence (r = -.13 and r = -.19, respectively) and positively associated with conflict engagement. Males scored higher on emotional intelligence (M = 121.96, SD = 13.73) than females (M = 118.35, SD = 15.87), and PhD students exhibited higher conflict resolution scores than Master's and undergraduate students. These findings highlight the impact of parenting styles on emotional intelligence and conflict resolution skills among young adults. Unique Contributions to Theory, Practice and Policy: The study is guided by The Social Learning Theory by Bandura (1977) sets that young adults copy ways of behaving gained from their childhood, particularly from their parents. Parenting styles perceived during childhood and adolescence could impact how people approach conflicts and social interactions. Another theory which backs this study is Emotional Intelligence theory by Daniel Goleman suggests that individuals consist of a bunch of skills and abilities that would help them in recognizing, understanding and managing their own self emotions as well as emotions of other people. The study recommends that research be conducted in other demographic regions or on a broader level. The study also recommends that other variables such as personality traits and changes over tine should be considered as well for better outcomes.

AIFIS controlled BLDC Motor Drive for Agricultural Application with Solar System

In India, it is of utmost significance to ensure that the agricultural fields receive supplies of water. Agricultural applications are the focus of this paper, which depicts the implementation of an advanced BLDC motor connected drive that is controlled by an adaptive neuro fuzzy inference system (ANFIS). In this work, the implementation of the bidirectional power flow among the load and the renewable energy source (RES) is carried out. In order to power the water pump, renewable energy sources (RES) are generated through the use of solar photovoltaic (PV) cells. Additionally, a BLDC motor load is connected to the water pump through a single phase bi-directional converter and a voltage source inverter (VSI) inside the design. The PV system is able to get the maximum amount of power while simultaneously lowering the main grid and enabling consumers to run their motors and loads at their maximum efficiency throughout the entire day. This is made possible by the integration of fusing into the solar generating framework. Using the suggested controller, the PV system is able to reduce conversion costs and total harmonic content of the grid, all while maintaining the power factor, good quality in power, and stability of the system.

Airborne Alternaria Spores: 70 Annual Records in Northwestern Spain

This study presents data on the concentration of Alternaria spores in the atmosphere of the northwestern Iberian Peninsula. A non-viable volumetric method was used to collect the samples, resulting in a database of 70 annual. When the annual averages for each locality are calculated, Ourense stands out with 2152 spores/m3, followed by Vigo and Lugo, while Santiago de Compostela recorded the lowest concentrations. Focusing on the total data for each locality, the main sporulation period started in May and ended in October in all localities, centered on a single phase, with an earlier onset and longer duration in Ourense and Vigo. The number of days with concentrations in excess of 100 spores/m3 was very low in Santiago de Compostela, Ourense, and Vigo and null in Lugo. Temperature was the meteorological parameter for which the highest statistical correlation was obtained in all locations, being favorable to the concentration of spores in the air. Temperature ranges favorable to the presence of airborne spores in the study area ranged from 25.5 to 31.2 °C. Based on the analysis of the data collected, it is concluded that Alternaria spore concentrations are low throughout most of the year.

Structural, magnetic and electrical studies on nickel doped copper ferrite synthesized using sol-gel method

Nickel doped copper ferrite nanoparticles NixCu1-xFe2O4(x = 0.1, 0.3, 0.5, 0.7, and 0.9) have been prepared through well known sol-gel technique. Numerous analytical methods, including the Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and powder X-ray diffractometer (XRD), were used to analyze the synthesized materials. Synthesized sample XRD patterns reveal the single phase development of the spinel crystalline structure in the absence of any contaminant. The concentration of Ni ions rises with a corresponding decrease in crystallite size. Scanning electron microscopy (SEM) was also used to assess the microstructure. By using UV–Visible spectrometer an optical absorbance and through FTIR, two of ferrite's distinctive bands were verified. The M-H loops show that when the concentration of nickel ions increases, saturation magnetization varies. The Cyclic-Voltameter was used to perform the ionic electrochemical analysis. The NixCu1-xFe2O4 nanopowder's enhanced magnetic characteristics suggest that these substances would make good candidates for magnetic catalysts.

Controlled single step synthesis, structural and electrode response of honeycomb layered Li3Co2SbO6

We report, for the first time, a single step synthesis process of Li3Co2SbO6 in air medium using the solid state reaction route. The structural analysis confirmed single phase layered crystal structure comprising 2D diffusion path along a-axis and b-axis. The Rietveld refinement of Li3Co2SbO6 yielded monoclinic crystal structure with C2/m space group having cell parameters, a = 5.216 A°, b = 8.989 A° and c = 5.171 A° with Li/Co mixed occupancy. The TEM analysis corroborated the layered structure which is consistent with x-ray analysis. Raman and FTIR analysis confirmed the presence of -CoO6 and -SbO6 octahedra in Li3Co2SbO6 with edge shared arrangement to form a layered stack comprising tunnel type pathway for Li+ ion transport. The estimated electrical conductivity of Li3Co2SbO6 is found to be ∼6.9 × 10−8 Scm−1 with a band gap ∼ 3.5 eV that suggests poor electronic transport for storage cells. This was observed in the electrochemical response of the Li || LiPF6(EC/EMC) || Li3Co2SbO6 cell. The 1st discharge capacity of Li3Co2SbO6 has been found to be a meagre 45 mAhg−1. Despite lower reversible capacity due to poor electrical transport, stable coulombic efficency observed up to 100 cycles suggest the feasibility of improvements in the electrical and charge transport properties.

Drug Delivery System That Self-Emulsify: Transportation of Drug From Gut to Target Organs

Microemulsions are highly popular for their specific uses, including vivid applications and this is due to their special properties, which include very high interfacial interactions with demonstrated stability from a thermodynamics point of view, and on the other hand, also very low interfacial tension, which is required to solubilize highly immiscible dispersions. This review’s goal is to briefly outline potential uses of micro-emulsion systems, their uses, limitations and possible in-vitro and in-vivo techniques. To characterise such dispersion systems, it is commonly known that adding the right surfactant or surfactant mixture can combine large amounts of two non-dissolving-target liquids, such as water and oil, into a single phase that is macroscopically homogeneous but microscopically heterogeneous. Owing to the advantages of lymph drug delivery, the drug-lipid conjugates, when they enter the lymph route, become an ideal approach for enhancing the absorption of such drugs to combat metastatic cancers of the lymph nodes and their drainage to specific organ systems where the cancer is already spread. As the route of lymph delivery is important where a tumor has already been cancerous, this formulation approach has distinct opportunities to transport needy molecules to cancerous sites in various organs, which also includes the lymph nodes. This review, particularly, lays more stress on an overview of microemulsions in general, the in-vivo and in-vitro characterization methods and potential applications related to target drug delivery via the lymphatic circulatory system.

Enhanced Solubility and Miscibility of CO2-Oil Mixture in the Presence of Propane under Reservoir Conditions to Improve Recovery Efficiency

The existence of propane (C3H8) in a CO2-oil mixture has great potential for increasing CO2 solubility and decreasing minimum miscibility pressure (MMP). In this study, the enhanced solubility, reduced viscosity, and lowered MMP of CO2-saturated crude oil in the presence of various amounts of C3H8 have been systematically examined at the reservoir conditions. Experimentally, a piston-equipped pressure/volume/temperature (PVT) cell is first validated by accurately reproducing the bubble-point pressures of the pure component of C3H8 at temperatures of 30, 40, and 50 °C with both continuous and stepwise depressurization methods. The validated cell is well utilized to measure the saturation pressures of the CO2-C3H8-oil systems by identifying the turning point on a P-V diagram at a given temperature. Accordingly, the gas solubilities of a CO2, C3H8, and CO2-C3H8 mixture in crude oil at pressures up to 1600 psi and a temperature range of 25–50 °C are measured. In addition, the viscosity of gas-saturated crude oil in a single liquid phase is measured using an in-line viscometer, where the pressure is maintained to be higher than its saturation pressure. Theoretically, a modified Peng–Robinson equation of state (PR EOS) is utilized as the primary thermodynamic model in this work. The crude oil is characterized as both a single and multiple pseudo-component(s). An exponential distribution function, together with a logarithm-type lumping method, is applied to characterize the crude oil. Two linear binary interaction parameters (BIP) correlations have been developed for CO2-oil binaries and C3H8-oil binaries to accurately reproduce the measured saturation pressures. Moreover, the MMPs of the CO2-oil mixture in the presence and absence of C3H8 have been determined with the assistance of the tie-line method. It has been found that the developed mathematical model can accurately calculate the saturation pressures of C3H8 and/or CO2-oil systems with an absolute average relative deviation (AARD) of 2.39% for 12 feed experiments. Compared to CO2, it is demonstrated that C3H8 is more soluble in the crude oil at the given pressure and temperature. The viscosity of gas-saturated crude oil can decrease from 9.50 cP to 1.89 cP and the averaged MMP from 1490 psi to 1160 psi at 50 °C with the addition of an average 16.02 mol% C3H8 in the CO2-oil mixture.

Modified multi-metal Prussian blue analogues toward high-performance cathode for sodium-ion battery

Increasing demand for energy storage devices coupled with lithium precursor shortage opens up a new opportunity for sodium-ion batteries (SIBs) to be considered as a replacement of lithium-ion batteries to become a new generation of energy storage device for commercial application. Prussian blue analogue (PBA) demonstrates great advantages as the cathodes for SIB owing to its simple synthesis method, inexpensive raw materials, and high theoretical specific capacity. Single phase multi-metal based PBA of Na1.92(Mn0.3Fe0.23Co0.3Ni0.17)[Fe(CN)6]0.88⋅2.16H2O with low contents of crystal water and [Fe(CN)6]4–defects was obtained by controlling the nucleation reaction rate via using sodium citrate as a chelating agent, and the assistance of N2 as an antioxidant and a protective gas. The obtained PBA with high purity and high crystallinity delivers a specific capacity of 120 mAh g−1, excellent rate capability, and impressive cycling performance with 82 % capacity retention after 1000 cycles.

Flow boiling in a rectangular micro/mini channel with self-rewetting and non-rewetting fluids

In this experimental investigation the influence of self-rewetting during flow boiling was studied in a horizontal microchannel during one-sided uniform heating. The channel had a width and height of 6 mm and 0.3 mm respectively. Local wall temperature and direct in-time flow visualisation was performed. The working fluids under consideration included water as base reference, pure 1-butanol, pure ethanol, dilute butanol-water self-rewetting mixtures, and a dilute ethanol-water binary mixture. Tests were conducted at mass fluxes of 10, 15 and 25 kg/m2s, over a range of heat fluxes to produce both single phase and two-phase quasi steady state flow data. Within the wall temperature ranges of interest, the butanol-water mixtures (5 % and 7 % by volume butanol) had surface tension characteristics that would draw liquid toward local wall hotspots. Local and average wall temperatures and heat transfer coefficients were obtained and considered against the governing flow pattern visualisations. In contrast to the other fluids, the self-rewetting butanol-water mixtures exhibited significantly more stable flow and more predictable saturation flow boiling heat transfer coefficient trends across all heat fluxes under consideration. At the lowest mass flux, it was found that an increase in the heat flux resulted in an improvement in the self-rewetting fluids heat transfer performance, while at higher mass fluxes this dependence was diminished. Across all mass fluxes and heat fluxes the 5 % butanol-water outperformed its 7 % butanol-water counterpart. The tendency of self-rewetting to reduce local dry-out, even at low mass fluxes are demonstrated.

Non-equilibrium pathways to emergent polar supertextures.

Ultrafast stimuli can stabilize metastable states of matter inaccessible by equilibrium means. Establishing the spatiotemporal link between ultrafast excitation and metastability is crucial to understand these phenomena. Here we utilize single-shot optical pump-X-ray probe measurements to capture snapshots of the emergence of a persistent polar vortex supercrystal in a heterostructure that hosts a fine balance between built-in electrostatic and elastic frustrations by design. By perturbing this balance with photoinduced charges, an initially heterogeneous mixture of polar phase disorders within a few picoseconds, leading to a state composed of disordered ferroelectric and suppressed vortex orders. On the picosecond-nanosecond timescales, transient labyrinthine fluctuations develop, accompanied by the recovery of the vortex order. On longer timescales, these fluctuations are progressively quenched by dynamical strain modulations, which drive the collective emergence of a single vortex supercrystal phase. Our results, corroborated by dynamical phase-field modelling, reveal non-equilibrium pathways following the ultrafast excitation of designer systems to persistent metastability.

Notes on the general relativistic viscous ringed disk evolution

Abstract A ringed accretion disk (RAD) models a cluster of axi-symmetric co-rotating and/or counter-rotating tori orbiting in the equatorial plane of a central Kerr super-massive Black Hole. We discuss the time evolution of such a ringed disk within the general relativity framework. Our analysis presents a study of the evolving RAD properties using a thin-disk scheme and solving a diffusion-like evolution equation for a RAD in the Kerr spacetime. In the first stage of evolution there is the inter–disk interaction where the individual rings spread inwardly and outwardly, levelling the structure and forming a single distribution with maximum density determined by the initial spread of the component rings. Timescales are dependent on viscosity prescriptions. The early time luminosity, dominated by the dynamics of the inner ringed structure, shows a clear mark of the inner ringed structure. The RAD eventually reaches a single disk phase, building accretion to the inner edge regulated by the inner edge boundary conditions. The late–time luminosity associated to the ringed disk follows a power law decline for the final single disk. In the sideline of this analysis we also considered a modified prescription mimicking an effective turbulent viscosity in the early phases of the rings evolutions.

Novel CoFe2O4 / LaAlO3 nanocomposites: An impressive photocatalyst with p-n hetero-junction for improved H2 generation under visible exposure

The present work is devoted to the synthesis of perovskite LaAlO3 by Sol-Gel approach and its application for the photo-evolution of H2 in conjunction with cobalt ferrite CoFe2O4 prepared by nitrate route. The thermal analysis (TG/DSC) showed that the formation is completed at 600 °C. The X-ray diffraction (XRD) pattern is characteristic of a single phase, crystallizing in a rhombohedral symmetry with a crystallite size of 36 nm. The SEM micrographs revealed a homogeneous structure with an agglomeration of shaped grains (40–80 nm). The forbidden band (3.39 eV), calculated from diffuse reflectance data, is assigned to the ligand charge transfer O2−: 2p → Al3+: 3s orbital. As prepared, LaAlO3 is an n-type semiconductor as demonstrated from the capacitance - potential (C−2 - E) graph with an electron density of 9.4 × 1014 cm−3 due to oxygen under-stoichiometry. Attention was directed to photo-electrochemistry in connection with water reduction into hydrogen. With a negative conduction band potential (−0.11 VSCE), H2 generation can be synergized over the hetero-system by visible light. The photocatalytic capability of CoFe2O4 25%/LaAlO3 revealed a high H2 generation of 963 μmol g−1 in the alkaline electrolyte (NaOH, 0.1 M) with a catalyst dose of 1 mg mL−1, which is 1.3 times more than CoFe2O4 under similar conditions. Photoactivity is significantly improved by 60%, up to 2400 μmol g−1 in the presence of oxalate C2O42− as a hole scavenger in the hetero-junction, two hydrogen release tests were successfully recorded. The higher H2 production in the hetero-junction system is attributed to the lower recombination rate of electron/hole (e−/h+) in the material, due to the large band bending at the solid interfacial.