REFLECTION

Structural and Optical Characterization of Cadmium Ferrite and Manganese Ferrite Nanoparticles synthesized via Co-precipitation route

REMYA MURALIMANOHAR — 2023-09-29

Spinel ferrite nanoparticles have been of tremendous interest in the arena of nanomaterial synthesis and has applications comprising industrial effluent treatment, as biosensors and for photocatalysis. Cadmium ferrite and manganese ferrite nanoparticles have been in the limelight recently due to their versatile applications. In the present work, nanoparticles of cadmium ferrite and manganese ferrite were synthesized using chemical precipitation method and were calcined at 600 ⁰C and 1000 ⁰C. It was observed from the XRD pattern that the samples were in normal spinel structure. The grain size of the samples was calculated using Debye-Scherrer as well as Hall-Williamson method. The optical band gap was calculated from UV-Visible absorption spectrum. The vibrational properties of the samples were studied using micro-Raman technique.

Nanocellulose/Polyvinyl Alcohol Hydrogel with Adsorption and Photocatalytic Properties

Jasmine Jose — 2023-09-29

Multifunctional Nanocellulose/Polyvinyl alcohol hydrogels with adsorption and photocatalytic properties towards an anionic dye Metanil Yellow (MY) was investigated. Office wastepaper was used as the raw material for synthesizing nanocellulose. The hydrogels were fabricated via the sol-gel method. The adsorption and photocatalytic properties of the hydrogel were evaluated under dark and sunlight irradiation respectively. Photo-stability of the hydrogels was studied by evaluating their recyclability efficiency. This study clearly reveals the potential application of the present system for anionic MY dye degradation.

Room Temperature Photoluminescence Studies on Mn Doped and Sr Co-doped CuO Nanostructures

Akhil M Anand — 2023-09-29

Nanoparticles of Copper Oxide (CuO), Manganese (Mn)-doped CuO, and Mn and Strontium (Sr) co-doped CuO were synthesised via co-precipitation method. The XRD results show that the particles were monoclinic in structure, and the crystallite size increased from 23.83 nm for CuO, 25.47 nm for CuO: Mn (0.1), 26.10 nm for CuO: Mn (0.2), 26.65 nm for CuO: Mn (0.3) and 28.31 nm for CuO: Mn (0.3): Sr co-doped samples. The band gap of the nanoparticles decreases in the same sequence from 2.97 eV for CuO to 2.40 eV for the co-doped samples. Morphological analyses were carried out using FESEM. The polygon shape of CuO particle changes to a stacked platelet-like structure with high porosity. Mn and Sr co-doped particles exhibit highly stacked platelet structures with less porosity, which showed a variation in sample morphology with doping. From EDS analysis, the Mn atomic percentage for CuO:Mn (0.1), CuO:Mn (0.2) and CuO:Mn(0.3) samples were found to be increased in accordance with the increase in doping concentration of Mn in the samples. Room temperature PL spectra obtained at excitation wavelengths 400 and 500 nm for CuO, CuO:Mn(0.1), CuO:Mn(0.2), CuO:Mn(0.3) and CuO:Mn(0.3):Sr samples show prominent defect level emissions.

Plasmonic and Colorimetric Characteristics of Terbium ions in Sol-Gel derived Titanosilicate Glass

Athira Maria Johnson Johnson — 2023-09-29

Terbium is one of the rare earth elements exhibiting emission in the visible range, which accounts for several optical applications. The effect of plasmonic nanoparticles of silver on the fluorescence enhancement of terbium ions doped titanosilicate matrix is investigated in the present work. The non-hydrolytic sol-gel method is used to synthesize Ag nanoparticles doped Tb³⁺: SiO₂– TiO_2.XRD does the structural characterisation, and TEM analysis confirms the presence of nanocrystals. FTIR spectroscopy is done to verify the matrix formation. Photoluminescence characteristic studies are performed to analyse the effect of silver nanoparticles in the fluorescence enhancement of the terbium ions, which is discussed as the consequence of the energy transfer phenomenon and localised surface plasmon resonance. Colorimetric characterisation confirms the colour-tunable capability of silver nanoparticles

ECONOMIC WAY OF SYNTHESIS OF GREEN FLUORESCENT CARBON NANO PARTICLES FROM LEMON JUICE AS A NEW CARBON SOURCE

SUMITHA TOM PAZHAMPALLIL — 2023-09-29

ABSTRACT

In the development of materials science, carbon-based materials are crucial. Carbon nanoparticles (CNPs) are one of the most interesting carbon-based nanomaterials which because of water insolubility formerly could not be employed in the biological fields. Recently, large efforts have been made to develop green routes in order to synthesize water soluble CNPs from economic sources. In this regard, in this study a simple ecofriendly economic method for the preparation water soluble green fluorescent Carbon Dots (CNPs) have been developed by microwave assisted method from lemon juice. The synthesized CNPs were characterized by UV-Visible absorption spectra, Fluorescence spectrophotometer as well as Fourier Transform Infrared Spectroscopy (FTIR). The results reveal that the as prepared CNPs emit bright green photo luminescence and the surface was rich in hydroxyl and carboxylic groups and shows excellent water solubility. The one-step economic green preparation process is simple and efficient and it is not necessary to use a strong acidic solvent or modify the surface of the reagent, which makes this approach very suitable for large-scale production, strong fluorescence and excellent biocompatibility.

Microwave-mediated green synthesis of silver nanoparticles using glycosmis pentaphylla leaf extract and exploration of their antimicrobial properties

Nidhin Joy Vettakunnel — 2023-09-29

Over the past few decades, nanotechnology emerged as one of the most significant area of research in material science. Due to the remarkable physical, chemical, optical, and biological features, noble metal nanoparticles like gold, silver, palladium, and platinum are broadly used in various fields. In this study, a quick microwave-assisted, inexpensive, and environmentally friendly method was used to synthesize silver nanoparticles (AgNPs). Without using any harmful chemical substances, AgNPs were generated using Glycosmis pentaphylla leaf extract as a reducing and stabilizing agent. UV-visible spectrophotometry, X-ray diffraction, and Scanning electron microscopy were used for the evaluation of successful synthesis. The presence of AgNPs confirmed by the appearance of peak at 417 nm utilizing UV-Vis method and also established by X-ray diffraction patterns. The synthesised AgNPs were also examined for antimicrobial activity using the agar well diffusion method and found that synthesized AgNPs efficiently inhibited the growth of various gram-positive and gram-negative bacteria.

Timing and Spectral Analysis of Thermonuclear X-ray Burst from LMXB 4U 1636-536

Marykutty James — 2023-09-29

Here we are presenting the results of Thermonuclear X-ray burst of 4U1636-536 using ASTROSAT/LAXPC data during the year 2017. Light curve analysis of this source reveals 12 thermonuclear X-ray burst like events. All the bursts are very strong and the burst peak to persistent intensity < 9 times except two burst B2 and B10. Energy resolved burst profile shows the burst like event disappear above 30 keV. We fitted each burst in different energy range with model BURS and found that the decay time decreases with energy. For the spectral analysis, nH value was frozen to 0.25 atoms /cm^2.Time resolved spectral analysis shows that the flux and spectral data counts showed a maximum value at the peak time of each burst. The flux tends to show a decreasing manner after the peak time with respect to time duration.

Endosulfan induced stress responses in Cowpea (Vigna sinensis L.) var. kanjikuzhy

R B Smitha — 2023-09-29

Endosulfan (C₉H₆Cl₆O₃S), the pesticide frequently applied in plantations, is reported as detrimental to human life and other fauna causing several growth hazards. The present study revealed the application of endosulfan which can retard plant growth affecting seed germination, growth of shoots, fruiting, etc. Seeds treated with different concentrations of endosulfan (0.01% - 2.0%) served as the experimental plants while non-treated plants as a control. A significant decrease in seed germination was observed among the experimental plants (6.6% to 0.0%) over non-treated plants (100.0%). The amylase activity is correlated with the germination percentage. Total chlorophyll content and protein content were found to be decreased by the application of endosulfan, whereas total free proline content was found to be increased from 0.66 to 1.96 mg/gm tissue. Endosulfan treatment significantly increased the levels of peroxidase and catalase activity in both root and leaf samples. This data was further confirmed using histochemical assays.

Qualitative Phytochemical Tests and Bioactivity of Vitex negundo L. Leaf extracts against Aedes aegypti L.

Sallykutty Thomas Vaikkunnel House — 2023-09-29

Qualitative Phytochemical tests and bioactivity of aqueous, acetone and ethanolic leaf extracts of Vitex negundo L. against Aedes aegypti L. mosquito larvae were carried out. Alkaloid, carbohydrate, coumarin, flavonoid, phenol, tannin and triterpenoid were located in both acetone and ethanol extract except carbohydrate in acetone extract. Alkaloid was absent in aqueous extract. Anthocyanin, anthraquinone and protein were absent in all the extracts studied. For mosquito larvicidal activity Aedes aegypti L. 4^th Instar larvae were selected and the mortality percentage was calculated and compared. Different concentrations of aqueous, acetone and ethanol extracts (1mg/ml, 3mg/ml and 5mg/ml) with different time of exposure (24, 48 and 72 hours) were evaluated and the results showed that in aqueous extract mortality percentage was obtained (20%) only on 5mg/ml on exposure to 72 hours. Mortality percentage was zero in 1mg/ml and 3mg/ml on exposure to 24 and 48 hours. The highest mortality percentage (100%) was obtained both in acetone and ethanol extracts with concentrations of 3mg/ml and 5mg/ml on exposure to 48 and 72 hours respectively. The results revealed that mortality percentage was increases with increase in concentration as well as time of exposure in all the extracts studied.

Extended Coprime Graph of Finite Group

Rani Jose — 2023-09-29

Algebraic graph theory encompasses an interface between group and graph which proves to be one of the most productive areas. The concept of coprime graph was introduced by M. Sattanathan and R. Kala (2009). In this paper, we introduce a new graph namely extended coprime graph from the finite group and discuss some properties of extended coprime graph.