Large Scale MIMO Analysis Using Enhanced LAMA

Wireless Personal Communications - In this research work, we propose a enhanced large scale multi-input multi-output (MIMO) approximate message passing (LAMA) based optimal data detector for large...     

Application of ultrasonic incorporated with calcium gluconate maintains physicochemical quality of pink guavas during short-term storage at room temperature

Food Science and Biotechnology - The effectiveness of simultaneous calcium gluconate (0.5% w/v) (Ca-G) and ultrasonication (Ca-G + US) on physicochemical quality of pink guavas under...     

Synthesis and Study of Structural,Morphological and Magnetic Properties of ZnFe2O4 Nanoparticles

Superparamagnetic zinc ferrite (ZnFe₂O₄) nanoparticles were prepared by a surfactant assisted hydrothermal method and subjected to the heat treatment. The structure, vibrational, morphology, and magnetic properties of synthesized product were characterized by XRD, FT-IR, HR-SEM, and VSM measurements. XRD result confirms the formation of regular spinel structured ZnFe₂O₄ with space group of Fd3m and an average crystalline size was calculated as 21 nm and 28 nm for the samples annealed in air atmosphere at 300 °C and 600 °C. The HR-SEM image shows that the particles are in spherical shape with small aggregation. A room temperature superparamagnetic behavior was observed for both samples. The saturation magnetization (M _s) of 12.0 emu/g and 9.10 emu/g were observed for the samples annealed in air atmosphere at 300 °C and 600 °C, respectively.     

Structural,morphological and magnetic properties of hydrothermally synthesized ZnFe2O4 nanoparticles

Zinc ferrite (ZnFe₂O₄) nanoparticles were synthesized by a surfactant assisted hydrothermal method using different concentrations of ethylamine (EA) namely, 2, 4, 6, 8 and 10 ml. The powder X-ray diffraction measurements revealed that the amount of EA plays an important role in the formation of single phase ZnFe₂O₄ nanoparticles. The amount of 2 and 4 ml of EA yielded mixed phases of α-Fe₂O₃ and ZnFe₂O₄ whereas 6 ml of EA produced well crystalline and single phase ZnFe₂O₄ with regular spinel structures. Field emission scanning electron microscopy images revealed that ZnFe₂O₄ possess spherical shape, irrespective of the concentrations of EA. Magnetic characterizations revealed that the synthesized samples with EA concentrations 6, 8, 10 ml were superparamagnetic in nature at room temperature.     

Role of monovalent co-dopants on the PL emission properties of YAl_3(BO_3)_4:Ce~(3+) phosphor

The cerium(Ce3+) doped yttrium aluminium borate(YAB) phosphor was synthesized by modified solid state reaction. The phosphor's phase purity and its emission properties were studied using powder X-ray diffraction pattern and photoluminescence spectroscopy. The synthesized YAB had rhomobohedral crystal structure. The phosphor had two different excitation and emission spectra.By 325 nm excitation, the phosphor had emission at 373 nm and with 363 nm excitation; the phosphor gave violet-blue emission at 418 nm.The UV emission of the phosphor originated due to Ce3+ ions at the yttrium site and violet-blue emission owing to Ce3+ ions at non-regular sites viz., Al3+ and interstitial sites. The emission intensity of the phosphor was enhanced when monovalent ions(K+, Na+, and F–) were added as co-dopants. The crucial role of ionic radii of monovalent co-dopants on the emission enhancement of the YAB:Ce3+ phosphor was reported. Thermogravimetric study showed that the YAB possessed high thermal stability at up to 900 ℃.     

Synthesis of superparamagnetic ZnFe2O4 nanoparticle by surfactant assisted hydrothermal method

Zinc ferrite (ZnFe₂O₄) ultrafine powder was synthesized by hydrothermal method using various amounts of cetyltrymethylammonium bromide (CTAB) as a surfactant. The phase purity, thermal stability, morphology, size and magnetic properties of the final products were studied. All the synthesized products were possessing normal spinel structure without any impurities. The crystalline size of synthesized products decreased with the increasing amounts of surfactant. Particles had narrow size distribution with an average particle size of 6.5 nm for 1.5 g of CTAB. Magnetic characterizations revealed that the synthesized products were superparamagnetic in nature.     

Structural and Carrier Dynamics of GaN and AlGaN-Based Double Heterostructures in the UV Region

Aluminum gallium nitride-based double heterostructures with two different active layer widths have been grown on GaN templates by metalorganic chemical vapor deposition. Crystalline quality has been investigated using high-resolution x-ray diffraction analysis, and screw, edge, as well as total dislocation densities in the GaN epilayer have been calculated. The dislocation density of GaN has been found to be on the order of 10⁸ cm^?2. The nominal Al composition and in-plane strain ε _xx for the AlGaN layer grown on the GaN layer have been measured by asymmetric reciprocal-space mapping. Surface properties and cross-sectional views of the samples have been analyzed using atomic force microscopy (AFM) and field-emission scanning electron microscopy (FESEM), respectively. Room-temperature time-resolved photoluminescence and photoluminescence measurements have been performed on Al_0.18Ga_0.82N/Al_0.45Ga_0.55N double heterostructures and the GaN template. The interface recombination velocity (S) of AlGaN-based double heterostructures has been calculated using carrier decay time measurement, increasing from 8.7 × 10³ cm/s to 13.4 × 10³ cm/s with varying active layer thickness.     

Influence of lanthanide ion on the morphology and luminescence properties of cadmium sulphide nanocrystals

An interesting shape evolution of cadmium sulphide nanocrystals is observed in the presence of a multidendate ligand, ethylenediamine tetra acetic acid (EDTA). In our study, EDTA is used as a capping agent and a ligand forming complex with the trivalent gadolinium ion for the synthesis of cadmium sulphide (CdS) nanoparticles. EDTA-capped CdS nanocrystals and gadolinium (Gd) doped CdS nanoneedles have been synthesized using wet chemical route. Addition of Gd as a dopant to the nanocrystals resulted in formation of luminescent CdS nanoneedles. Fourier transform infrared spectroscopy, energy dispersive X-ray analysis, X-ray diffraction, optical absorption, photoluminescence measurements, scanning and transmission electron microscopic measurement techniques were employed to characterize the samples. Photoluminescence investigation revealed the highly luminescent behavior of the CdS nanoneedles. Further, cathodoluminescence mapping confirmed the excellent luminescent properties, which can be exploited for the fabrication of optoelectronic devices.     

Recent advancements in Dragline control systems

This paper discusses about the robust machine “Dragline”, from century old techniques employed for power transmission, control and operation to the recent trends. Dragline is mostly used in mining sector for removal of overburden as it is highly economical in comparison to the usage of shovel–dumper combination of the same, however the deployment of dragline is subjected to the geographical conditions of the mine. Dragline in general mostly comprises Drag, Hoist and Swing mechanism. For the Drag, Hoist and Swing operations earlier DC machines are used with Ward–Leonard control mechanism, but recently due to advancements in power electronic devices AC motors found their application for the same due to their less maintenance costs and also reducing the number of machines resulting in increasing the overall efficiency. Also, gear less power transmission techniques are in place. In parallel, the control techniques are also getting evolved and automation is taking place starting with Swing mechanism extending to the whole operation.