Novel low-temperature synthesis of Y2-x O3 :Eux 3+ nanophosphor using combustion with thioglycerol as fuel for near-UV light-emitting diodes.

Luminescent materials used in flat panel displays, compact fluorescent lamps, and light-emitting diodes require high purity, uniform particle size, clean surfaces, spherical shape, and dense morphology to ensure long-term stability. Y2 O3 :Eu3+ is a widely studied red phosphor known for its characteristic photoluminescence (PL) emission at 613 nm with near-UV excitation at 392 nm. Many methods have been explored to synthesize Y2 O3 :Eu3+ nanoparticles with exceptional purity, consistent phases, and uniform particle sizes. The aim is to synthesize particles with pristine surfaces, spherical shape, and compact morphology. This study focuses on the low-temperature synthesis and PL investigation of Y2-x O3 :Eux 3+ nanophosphors using combustion with thioglycerol as fuel. The results are compared with Y2-x O3 :Eux 3+ red nanophosphors synthesized using wet chemical and nitrate combustion methods. The PL characteristics of the Y2-x O3 :Eux 3+ nanophosphors were analyzed using PL emission spectroscopy, X-ray diffraction, and scanning electron microscopy. These findings highlight the advantageous properties of the synthesized nanophosphors, such as their suitability for solid-state lighting applications in the lamp industry as highly efficient red phosphors. The combination of high purity, uniform particle size, clean surfaces, spherical shape, and dense morphology contributes to their potential for long-term stability and reliable performance in lighting devices.

Comparative assessment in enzyme activities and microbial populations during normal and vermicomposting.

Changes in extracellular enzyme activities and microbial populations were studied during the normal composting and vermicomposting of fruitpulp, vegetable waste, groundnut husk and cowdung. The microbial numbers and their extracellular enzyme profiles showed relative variation and were found increasingly more abundant in vermicompost than in normal compost leading to the conversion of agricultural waste into value added product. In vermicompost, the maximum enzyme activities (cellulase, amylase, invertase, protease and urease) were observed during 21-35 days. The cellulase, amylase and protease activities of vermicompost reached the maximum values by 28th day of 1175, 825 microg reducing sugar g(-1) hr(-1) and 28 micro mol of aminoacid g(-1) hr(-1) of vermicompost samples respectively. Similarly the invertase and urease activities reached to peak values of 876 microg reducing sugar g(-1) hr(-1) and 197 microg NH4(+)-N g(-1) ha(-1) sample on 35th day respectively. Most of the enzymes showed correlation with change in number and types of different microbial groups like bacteria, fungi and actinomycetes during vermicomposting with maximum number of 126 x 10(6), 28 x 10(4) and 93 x 10(5) CFU g(-1) sample respectively. In contrast delayed greatest enzyme activities were observed on 42-49th day i.e., last days of normal composting. Earthworms stimulated biochemical activity and nutrient cycling by 40-45% contributing to the reduction of period of degradation of agricultural wastes resulting in maturation of vermicompost by 28th day.