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Preparation characterization and applications of mixed oxides ceria-samaria supported on rice husk ash as catalysts for organic synthesis
Catalysis is a well-established scientific discipline, dealing with fundamental principles involved in the preparation, properties, applications and mechanisms of catalytic reactions of various catalysts. The preparation of silica from agricultural waste rice husk is an economical and environmentally benign process. Mixed oxides of ceria and samaria are a multifunctional catalytic system that has attracted wide-range of research in different fields. These mixed oxide catalysts are generally used for redox reactions and acid-base reactions in organic synthesis. The catalytic activity of these materials can be enhanced by using silica as a support system. To achieve the best structural and morphological features, different synthetic protocols were tried out while incorporating CeO2 and Sm2O3 on SiO2 to maximize the catalytic efficacy. In the present study, bimetallic oxides of ceria and samaria supported on silica catalysts were prepared by ultra sonicator, rota vapour method, wet impregnation and incipient wet impregnation methods. Further modification of ceria-samaria-silica catalysts using MoO3, La2O3 and mixed forms of MoO3 and La2O3 led to the formation of tri or tetra metallic mixed oxides on silica system. A detailed physico chemical characterization of the prepared catalysts using different spectroscopic and non-spectroscopic methods was carried out to understand the nature, stability and the functional groups present in the system. The heterogeneous catalytic route for organic synthesis is of major interest as it is sustainable and eco-friendlier. Utilizing biowaste like rice husk and its modified forms to synthesize useful and industrially significant organic compounds has been attempted with success in the present work. Thus, the prepared catalysts were subsequently evaluated for their catalytic activity towards oxidation, esterification, transesterification and Friedel Crafts' benzylation reactions. To achieve maximum yield and good selectivity, the different reaction parameters were optimized for all the reactions that were studied. Oxidation of cyclohexanone with benzyl alcohol to caprolactone and benzaldehyde has been studied after optimizing the reaction parameters. Recycle and leaching studies were conducted to understand the stability and reusability of the catalytic system for the above-mentioned reactions. These catalysts were also found effective in the synthesis of caprolactone, which is an intermediate in the synthesis of biodegrading polymers. Selective oxidation of benzyl alcohol to benzaldehyde too has been achieved using these catalysts. Surface area and acidity have played major roles in these reactions. Finally, dibenzyl toluene was synthesized by benzylation of toluene using benzyl chloride. In all the studies, plausible mechanisms involving the catalyst have also been suggested. Thus, a comprehensive study of rice husk silica-supported ceria and samaria systems and the multi metal oxide silica systems has been conducted and it has proved to be an efficient, recoverable, stable and eco-friendly catalyst combined with simple workup for industrially important organic syntheses. -
Preparation and Electrochemical Investigation of NiO Hollow Sphere from Bio Waste (Sugarcane Bagasse) Extract for Energy Storage Applications
This work describes how to easily make NiO hollow sphere composites using waste sugarcane bagasse for use in supercapacitor applications. NiO hollow spheres (NOHSs) nanomaterialis effectively synthesized through the nano carbon sphere (CS) template. A core-shell structure was created on the carbon spheres surface by NiO nanoparticles that were several nanometers in size. The structural and morphological of the synthesized materials were investigated by X-ray diffraction (XRD) and Scanning electron microscope (SEM). The energy-dispersive X-ray spectroscopy (EDS) was used to confirm the presence of the elements in NOHS. The electrochemical behaviour of hierarchical CSs and NOHSs electrode was examined through cyclic voltammetry (CV), Galvanostatic charge/discharge (SC) and electrochemical impedance spectroscopy (EIS). In GCD analysis, NOHSs electrode showed a concentrated specific capacitance (Csp) of 913.79F/g at 5A/g current density. The porous conductive carbon with macro pores that speeds up the transit of electron and electrolyte ions causes noticeably better capacitive behavior. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024. -
Preparation and Characterization of Tungsten Carbide/Epoxy Composites for J-Ray Shielding
Polymer composites have attracted considerable attention as potential light weight and cost-effective shielding materials which could be used for applications in nuclear reactors, nuclear waste transportation, as protective cloth/apron for personnel in hospitals, and shielding instruments on-board satellites from space radiations. In this context, we have developed diglycidyl ether of bisphenol A (DGEBA)-based epoxy resin composites loaded with tungsten carbide (WC) for J-ray shielding. Epoxy composites containing different loadings (0, 10, 30 and 50 wt%) of WC were synthesized by room temperature solution casting technique. Structural and morphological studies of the composites were performed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Thermal and tensile properties of epoxy were enhanced in the presence of WC fillers. Thermogravimetric analysis revealed the major degradation temperature occurring between 430C and 580C for all epoxy/WC composites. The tensile strength and Youngs modulus of the composites enhanced with loading, owing to greater intermolecular reinforcing effect, uniform stress distribution and enhanced energy-absorbing capacity. J-Ray attenuation studies performed in the energy region of 0.356 1.332 MeV using NaI(Tl) detector spectrometer showed the 50 wt% tungsten carbide/epoxy composites to have highest radiation attenuation at all the energies. The overall enhancement in thermal, mechanical, and radiation shielding characteristics of the composites may be attributed to the uniformity in distribution of the fillers in epoxy matrix. These nontoxic tungsten carbide/epoxy composites may be suitable as materials for shielding in radiation environments. 2022 American Institute of Physics Inc.. All rights reserved. -
Preparation and characterisation of amorphous mesoporous aluminophosphate and metal aluminophosphate as an efficient heterogeneous catalyst for transesterification reaction.
Volume 14, Issue 12, December 2011, Pages 1109-1116 -
Preparation and characterisation of amorphous mesoporous aluminophosphate and metal aluminophosphate as an efficient heterogeneous catalyst for transesterification reaction
Preparation, characterisation of pure aluminophosphate and aluminophosphate modified with different transition metals (V, Fe, Co Ni & Cu) and their catalytic activity in mono/dibenzyl substituted malonates synthesis are explained. The materials were prepared by the coprecipitation method in the absence of any structure-directing species and characterized for their composition, crystalline nature, total surface acidity, specific surface area pore diameter and pore volume by different techniques. Catalytic activity of the materials was investigated in transesterification of diethylmalonate with benzyl alcohol in liquid phase. Pure aluminophosphate resulted only in benzyl ethylmalonate whereas the incorporation of transition metals favored the formation of both benzyl ethylmalonate and dibenzylmalonate. Catalytic activity parallels the surface acidity and mesoporosity of the catalysts. The effect of the molar ratio of reactants, amount of catalyst, and reaction time on the conversion of diethyl malonate and transester yield has been studied. The highest activity of iron aluminophosphate is attributed to its mesoporous nature with uniform pore size distribution, higher surface acidity and surface area. Further, the scope and generality of iron aluminophosphate as a catalyst in the transesterification was studied using various aliphatic, alicyclic and aromatic alcohols. The catalysts could be recycled by retaining most of its initial activity. 2011 Acadie des sciences. Published by Elsevier Masson SAS. All rights reserved. -
Preparation and Application of Nanoparticles and Core-Shell Nanoparticles of Transition Metals
There is an increasing need for the development of environmentally viable, economically effective, highly active and renewable catalytic systems for the various applications in the industrial field. The demand for the decolorisaion of synthetic dyes using bioremediation methods has been in a decreased mode due to its lower decomposition rates. Hence in recent years the decomposition of these organic colorants considered to be a worldwide need. The term nanocatalysis has gained huge importance in recent years due to its selectivity, higher activity, and productivity compared to their bulk materials. The nanosize, shape, and large surface to volume ratio provide unique properties to the nanomaterials. The principles of green chemistry are mainly relies on the development of catalytic systems that work similar to nature. Nanocatalyst combines both homogeneous and heterogeneous catalysis and provides rapid and selective chemical transformations with high yield and easier separation of catalyst at the end of reaction. In this work we have synthesized various metal doped magnetite nanoparticles (Ferrite nanoparticles-NdMxFe3-xO4 where M (Mn, Co, Cu, Ni)) by precipitation and hydrothermal method. The one objective of this work was to check the photocatalytic application of prepared ferrite nanoparticles for the heterogeneous photo-Fenton degradation of MB and Rh B dyes. Each dye was degraded separately under visible light and dark with the assistance of neutral pH and H2O2, in order to shows the improved activity of catalysts under visible light. The degradation experiments using the photo-Fenton systems (Fe2+/H2O2/Visible light) suggested that, the highest degradation rate was 97% for MB and 81% for Rh B within 4h and the used catalyst was NdFe3-xCuxO4, a good photo-Fenton catalyst. . We have also tried the synthesis of core- shell nanoparticles using NdFe3O4 nanoparticles with the help of polyethylene glycol as dispersing agent. The synthesized samples were characterized by various techniques like, XRD, XPS, SEM and TEM. -
Prehistorian indoor navigation based on sensory invasion for visually challenged people /
Patent Number: 202141024018, Applicant: Dr. M. Kasiselvanathan.
In this era, navigation continues to be a vital component in both outdoor and indoor environments, and many solutions have been given in both cases. Usually GPS is used for navigation, but in an indoor or underground environment, its signal is almost never available. In this work, we used LiDAR (Light Detection And Ranging) sensor and IMU sensor. LIDAR sensor is a famous remote sensing strategy utilized for estimating the specific distance of an item on the world's surface. -
Preferences of 24 hours news channel viewers in Kerala /
Keeping the demand of Infotainment programs, the media houses started producing news magazines, entertainment magazines and news programs for different channels. Within a short span of time news journalism became so popular in Kerala and now more and more media houses were planning to setup their news channels in the state. By several measures news channels has come to realize the potential for news broadcasting. Each network has dramatically expanded their news programming over the decades and TV news producers take great pains to make their stories visually appealing to present news instantaneously and to make viewers feel they are a part of the events shown. New computerized graphical techniques present technical and statistical data in compelling formats. -
PREFERENCES OF 24 HOURS NEWS CHANNEL VIEWERS IN KERALA
Keeping the demand of Infotainment programs, the media houses started producing news magazines, entertainment magazines and news programs for different channels. Within a short span of time news journalism became so popular in Kerala and now more and more media houses were planning to setup their news channels in the state. By several measures news channels has come to realize the potential for news broadcasting. Each network has dramatically expanded their news programming over the decades and TV news producers take great pains to make their stories visually appealing to present news instantaneously and to make viewers feel they are a part of the events shown. New computerized graphical techniques present technical and statistical data in compelling formats. Broadcast organizations routinely conduct researches to keep up to date on what audiences preferences about the news and continuous feedback also make television an ideal medium to satisfy the demands of the people. In addition to the presentation of more news in more technically advanced formats, there's an audience presumably better able to understand news. Thus the study will find out the characteristics and preferences of news viewing population in Kerala. -
Preface: Motivation for this Book
[No abstract available]