Vignan University

About: Vignan University is a education organization based out in Guntur, Andhra Pradesh, India. It is known for research contribution in the topics: Control theory & CMOS. The organization has 1138 authors who have published 1381 publications receiving 7798 citations.

A novel E-learning framework to learn IT skills for visual impaired

Abstract: In this paper a novel approach is implemented for learning of IT related courses for visually impaired through e-learning which provides a facility for anyone to learn from anywhere at anytime. It enables visually impaired students to learn the knowledge by accessing the e-content and work more independently with ease of access compared to traditional methods. At present most of eLearning websites are providing the content mostly useful for normal students. Using screen readers, learning of the content from these websites are cumbersome for visual impaired. A survey has been carried out on a batch of visually impaired students to explore existing eLearning concepts and tools in IT related courses. This work is mostly focused on the issue of web accessibility and to facilitate effective access of content and learning to the visually-impaired students. The methodology used in this paper is validated by visually-impaired students and experts and yielded good results. It is also tested for portability of using with various modes of access such as personal computers, Tablets and Mobile phones.

Dielectric and piezoelectric properties of Sm3+ doped lead barium niobate (PBN) ceramics

Abstract: Rhombohedral samarium doped Lead based ceramic materials were fabricated by a high temperature conventional solid state mixed oxide ceramic process. The ceramic composition Pb1-x-3y/2Bax Re y 3 + Nb2O6 (x = 0.35 and y = 0.00, 0.02, 0.04 and 0.06, Re3+ = Sm3+). The pure and Sm3+ doped lead barium niobate ceramic materials are single phase with rhombohedral(hexagonal) symmetry obtained from powder x-ray diffraction (XRD). The grain size has been measured for all the compositions and lying between 1.60 and 2.90 μm. Broad dielectric peak phase transitions observed with temperature in pure and Sm3+ ion modified lead barium niobate ceramic materials. It is observed that the high values of piezoelectric charge coefficients in d31 and d33 in Sm3+ doped lead barium niobate ceramics. The mechanical quality factor Qm and d33 increases with increase of Sm3+ ion concentration and indicating a highly polarisable lead ion contributing to high Curie temperature dielectric constant.

Determination of flow front velocity and optimal injection pressures for better impregnation of E-glass with polyester in resin transfer mold

Abstract: Flow front velocity of resin plays a key role in yielding better impregnation of fiber reinforcement in resin transfer molding to fabricate quality composites. A video camera was used to capture the patterns of resin flowing below the grid lines drawn on the acrylic sheet of resin transfer mold and also to accurately measure the flow front velocity using an image conversion tool. The effect of flow front velocity, permeability, Reynolds number and void content at five different injection pressures on chopped strand E-glass/polyester composites consisting of 4, 5 and 6 layers has been studied. On the basis of Reynolds number of resin flow and void content present in the composite, optimal injection pressures are suggested for better impregnation of preform. Composites processed at these injection pressures gave superior properties in tension and flexure. Fractured parts of the specimens were examined on Scanning Electron Microscope to explain the causes of superior mechanical properties.