Indian Institute of Technology Bombay

About: Indian Institute of Technology Bombay is a education organization based out in Mumbai, India. It is known for research contribution in the topics: Population & Thin film. The organization has 16756 authors who have published 33588 publications receiving 570559 citations.

Automatic recognition of features from freeform surface CAD models

Abstract: This paper reports the design and implementation of a system for automatic recognition of features from freeform surface CAD models of sheet metal parts represented in STL format. The developed methodology has three major steps viz. STL model preprocessing, Region segmentation and automated Feature recognition. The input CAD model is preprocessed to get a healed and topology enriched STL model. A new hybrid region segmentation algorithm based on both edge- and region-based approaches has been developed to segment the preprocessed STL model into meaningful regions. Geometrical properties of facets, edges and vertices such as gauss and mean curvature at vertices, orientations of facet normals, shape structure of triangles, dihedral edge angle (angle between facets), etc. have been computed to identify and classify the regions. Feature on a freeform surface is defined as a set of connected meaningful regions having a particular geometry and topology which has some significance in design and manufacturing. Feature recognition rules have been formulated for recognizing a variety of protrusion and depression features such as holes, bends, darts, beads, louvres, dimples, dents, ridges/channels (blind and through) etc. occurring on automotive sheet metal panels. The developed system has been extensively tested with various industrial sheet metal parts and is found to be robust and consistent. The features data can be post processed and linked to various downstream CAD/CAM applications like automated process planning, sheet metal tool design, refinement of FEM meshes and product redesign.

"One-Pot" Protection, Glycosylation, and Protection-Glycosylation Strategies of Carbohydrates.

Abstract: Carbohydrates, which are ubiquitously distributed throughout the three domains of life, play significant roles in a variety of vital biological processes. Access to unique and homogeneous carbohydrate materials is important to understand their physical properties, biological functions, and disease-related features. It is difficult to isolate carbohydrates in acceptable purity and amounts from natural sources. Therefore, complex saccharides with well-defined structures are often most conviently accessed through chemical syntheses. Two major hurdles, regioselective protection and stereoselective glycosylation, are faced by carbohydrate chemists in synthesizing these highly complicated molecules. Over the past few years, there has been a radical change in tackling these problems and speeding up the synthesis of oligosaccharides. This is largely due to the development of one–pot protection, one–pot glycosylation, and one–pot protection–glycosylation protocols and streamlined approaches to orthogonally protect...

Aqueous Synthesis of Mn- and Co-Doped ZnO Nanorods

Abstract: Herein, we report the optical and magnetic properties of Mn- and Co-doped ZnO nanorods fabricated via a simple one-step aqueous-based chemical method. Interestingly, SEM results reveal a uniform size distribution of the nanorods throughout the substrate. The UV emission band of doped ZnO nanorods reveals a red shift from 382 to 384.5 nm, indicating a band-edge bending due to the dopants. The defect-related band centered at 600 nm is suppressed (ID/IUV = 1−0.35) considerably in doped nanorods, revealing the quenching of surface defects present in the nanostructures. XRD, XPS, Raman spectra, and EDS data demonstrate a successful incorporation of TM dopants in ZnO nanorods. Localized SAED patterns taken using nanoprobe size reveals that the nanorods are single crystals, grown along the c-axis [0002] direction. A systematic evalution of the enhancement in ferromagnetism (M = 0.15 × 10−2 to 1.3 × 10−2 emu/g) is found in modified doped ZnO nanorods.