Now showing items 1-3 of 3
| Abstract: | Demand on magnesium and its alloys is increased significantly in the automotive industry because of their great potential in reducing the weight of components, thus resulting in improvement in fuel efficiency of the vehicle. To date, most of Mg products have been fabricated by casting, especially, by die-casting because of its high productivity, suitable strength, acceptable quality & dimensional accuracy and the components produced through sand, gravity and low pressure die casting are small extent. In fact, higher solidification rate is possible only in high pressure die casting, which results in finer grain size. However, achieving high cooling rate in gravity casting using sand and permanent moulds is a difficult task, which ends with a coarser grain nature and exhibit poor mechanical properties, which is an important aspect of the performance in industrial applications. Grain refinement is technologically attractive because it generally does not adversely affect ductility and toughness, contrary to most other strengthening methods. Therefore formation of fine grain structure in these castings is crucial, in order to improve the mechanical properties of these cast components. Therefore, the present investigation is “GRAIN REFINEMENT STUDIES ON Mg AND Mg-Al BASED ALLOYS”. The primary objective of this present investigation is to study the effect of various grain refining inoculants (Al-4B, Al- 5TiB2 master alloys, Al4C3, Charcoal particles) on Pure Mg and Mg-Al alloys such as AZ31, AZ91 and study their grain refining mechanisms. The second objective of this work is to study the effect of superheating process on the grain size of AZ31, AZ91 Mg alloys with and without inoculants addition. In addition, to study the effect of grain refinement on the mechanical properties of Mg and Mg-Al alloys. The thesis is well organized with seven chapters and the details of the studies are given below in detail. |
| Description: | Materials Science and Technology Division, National Institute for Interdisciplinary Science and Technology (NIIST), CSIR |
| URI: | http://dyuthi.cusat.ac.in/purl/3132 |
| Files | Size |
|---|---|
| Dyuthi-T1106.pdf | (111.8Mb) |
| Abstract: | The fascinating photoluminescence properties of trivalent europium (Eu3+) coordination compounds have aroused tremendous interest in recent years due to their potential applications ranging from biomedical analysis to material science. The Eu3+ ions have excellent luminescent features such as long-lived excited-state lifetimes (μs–ms range) and narrow, easily recognizable line-like red emission bands with large Stokes shifts. A big challenge in the chemistry of lanthanide ions is to develop luminescent europium complexes that can be sensitized by visible-light. This field has become much more important because of the demand for less-harmful labelling reagents in the life sciences and lowvoltage- driven pure-red emitters in optoelectronic. Thus, the primary objective of the present research work is to design and develop novel visible-light sensitized Eu3+-β-diketonate complexes with impressive photophysical propertiesThe thesis comprises of four chapters which are presented as independent units and therefore the structure formulae, schemes, figures and references are numbered chapterwise. The introductory chapter highlights a background sketch of the use of β-diketonates as antenna ligands for Eu3+ ion, the recent developments in visible light excitable Eu3+-β-complexes and an overview of the various methods of synthesis of Eu3+-based silica hybrid materials, their photophysical properties and possible applications |
| URI: | http://dyuthi.cusat.ac.in/purl/5166 |
| Files | Size |
|---|---|
| Dyuthi-T2200.pdf | (13.14Mb) |
| Abstract: | Th(BrO3)3·H2O single crystals were grown from its aqueous solution at room temperature. Single crystal XRD, Raman and FTIR techniques were used to investigate the crystal structure. The crystal structure was solved by Patterson method. The as grown crystals are in monoclinic system with space group P21/c. The unit cell parameters are a = 12.8555(18) Å, b = 7.8970(11) Å, c = 9.0716(10) Å, = 90°, = 131.568° and = 90° and unit cell volume is 689.1(2) Å3. Z = 8, R factor is 5.9. The Raman and FTIR studies indicate the lowering of symmetry of bromate anion from C3V to C1. Hydrogen bonds with varying strengths are present in the crystal. The centrosymmetric space group P21/c of the crystal is confirmed by the non-coincidence of majority of Raman and IR bands |
| Description: | Crystal Structure Theory and Applications, 2013, 2, 70-74 |
| URI: | http://dyuthi.cusat.ac.in/purl/4561 |
| Files | Size |
|---|---|
| X-Ray Crysatllo ... horium Bromate Hydrate.pdf | (592.1Kb) |
Now showing items 1-3 of 3
Dyuthi Digital Repository Copyright © 2007-2011 Cochin University of Science and Technology. Items in Dyuthi are protected by copyright, with all rights reserved, unless otherwise indicated.