Post curing of Hansa-3 (VT- HNW) Components

This report contains the detads of post curing of Hansa-3 (VT- HNW) all composite airframe components provided byC-CADD, carried out using an in-house designed and fabricated large hot air oven (17mts x 2.0mts x 2.0mts). It details an optimum post cure cycle implemented, the temperature accuracy's, the various innovative approaches adapted to ensure the safety of the full scale components undergoing post cure in the oven. All the Hansa-3 (VT-HNW) airframe composite components post cured as per the standard optimum post cure cycle and the oven temperature monitored throughout around f 3degree C to ensure uniform post curing of components

A frictional Cosserat model for the flow of granular materials through a vertical channel

A rigid-plastic Cosserat model has been used to study dense, fully developed flow of granular materials through a vertical channel. Frictional models based on the classical continuum do not predict the occurrence of shear layers, at variance with experimental observations. This feature has been attributed to the absence of a material length scale in their constitutive equations. The present model incorporates such a material length scale by treating the granular material as a Cosserat continuum. Thus localised couple stresses exist and the stress tensor is asymmetric. The velocity profiles predicted by the model are in close agreement with available experimental data. The predicted dependence of the shear layer thickness on the width of the channel is in reasonable agreement with data. In the limit of the ratio of the particle diameter to the half-width of the channel being small, the model predicts that the shear layer thickness scaled by the particle diameter grows.Comment: 17 pages, 12 PostScript figures, uses AmsLaTeX, psfrag and natbib. Accepted for publication in Acta Mechanic

On the morphology of Bostrychia tenella (Vahl) J. Agardh

Boergesen (1937) reported Bostrychia tenella (Va hI.) J. Ag. from Indian waters. Some details regarding the morphology of the alga are available to some extent by the works of Montagne(1828).Falken\>"rg (1901). Post (1936). Tseng(1942)and Joly (1954) . The detailed structure of the alga and the development of the reproductive structures are not known completely. Advantage was taken of the occurrence of Bostrychia tenella in the Gulf of Mannar at Mandapam to study the morphology of the species both from living specimans and from material fixed in 4% formalin and forma lin -acatic-alcohol. Suitable preparations were stained in eosine and mounted in glycerine for microscopic examination. Sometimes the material had to be softened by placing in 1 % acetic acid or 1 % lithium chloride solution. While thin sections were used frequantly. most datails could be observed on whole mounts and squashes of suitable pieces of the thallus of the alga

Carrier Frequency Offset Estimation Algorithm in the Presence of I/Q Imbalance in OFDM Systems

In this paper, we analyzed the feasibility of using a virtual carrier based carrier frequency offset estimation algorithm in the presence of I/Q imbalance in OFDM systems. Based on the analysis of the signal model with both receiver CFO and I/Q imbalance impairment we conclude that it is feasible to extending the virtual carrier based CFO estimation algorithm to the I/Q imbalance scenario. The CFO estimation performance is evaluated through computer simulation. Impact of parameters on the estimation performance is investigated and it is consistent with our analysis. After CFO correction, a blind based I/Q imbalance estimation and compensation algorithm is applied. The final detection performance demonstrates that the virtual carrier based CFO estimation performance is good enough for subsequent I/Q imbalance estimation and compensation

A Novel Fuzzy Logic Based Technique to Find the Criticality of Power Transformer

Determining the current prevailing conditions in the transformer is still a challenge and an attempt is made for meeting the same challenge. In this paper a novel system based on fuzzy logic is developed which considers thermal, electrical and mechanical conditions prevailing in the transformer and gives the critical status of the transformer at an aggregate. The developed system also facilitates to give the critical condition of Paper thermal, Oil thermal, Partial discharge, Electrical arching, Dissolved gas analysis(DGA), Break down voltage and sweep frequency response analysis(SFRA) individually so that corresponding preventive measures can be taken by the technologists. This system consists of 10 fuzzy logic controllers whose connections are made by considering technical conditions and reasons, the corresponding rule bases of these fuzzy logic controllers were developed by considering various standards and experience of TIFAC CORE in NIT-Hamirpur. This fuzzy logic based system is tested for various transformers and found that it is highly précised in classifying the critical statues of any transformer as well as all identifying the current prevailing conditions