Shape memory alloy based smart landing gear for an airship

The design and development of a shape memory alloy based smart landing gear for aerospace vehicles is based on a13; novel design approach. The smart landing gear comprises a landing beam, an arch, and a superelastic nickeltitanium shape memory alloy element. This design is of a generic nature and is applicable to a certain class of light13; aerospace vehicles. In this paper a specixFB01;c case of the shape memory alloy based smart landing gear design and13; development applicable to a radio controlled semirigid airship (radio controlled blimp) of 320 m3 volume is13; presented.Ajudicious combination of carbon xFB01;ber reinforced plastic for the landing beam, cane (naturally occurring13; plant product) wrapped with carbon xFB01;ber reinforced plastic for the arch, and superelastic shape memory alloy is13; used in the development. An appropriate sizing of the arch and landing beam is arrived at to meet the dual requirement of low weight and high-energy dissipation while ndergoing x201C;large elasticx201D; (large nonlinear recoverable13; elastic strain) deformations to ensure soft landings when the airship impacts the ground. The soft landing is required13; to ensure that shock and vibration are minimized (to protect the sensitive payload). The inherently large energydissipating character of the superelastic shape memory alloy element in the tensile mode of deformation and the superior elastic bounce back features of the landing gear provide the ideal solution.Anonlinear analysis based on the classical and xFB01;nite element method approach is followed to analyze the structure. Necessary experiments and tests have been conducted to check the veracity of the design. Good correlation has been found between the analyses and testing. This exercise is intended to provide an alternate method of developing an efxFB01;cient landing gear with satisfactory geometry for a x201C;certain class of light aerospace vehiclesx201D; such as airships, rotorcraft, and other light unmanned air vehicles

Descriptions of new species of oriental Mymaridae and Aphelinidae (Hymenoptera: Chalcidoidea)

A new genus and species, Kubja longipes from Sabah, Hispaniella tenia sp. nov. from Pakistan; Parallelaptera teleonemiae sp. nov.; Eretmocerus breviclavus sp. nov.; Encarsia longifasciata sp. nov.; Azotus bharathius sp. nov.; Azotusfumipermis sp. nov., all from India and of economic importance, are described

Analysis of Acoustic Emission Signals using WaveletTransformation Technique

Acoustic emission (AE) monitoring is carried out during proof pressure testing of pressurevessels to find the occurrence of any crack growth-related phenomenon. While carrying out AEmonitoring, it is often found that the background noise is very high. Along with the noise, thesignal includes various phenomena related to crack growth, rubbing of fasteners, leaks, etc. Dueto the presence of noise, it becomes difficult to identify signature of the original signals related to the above phenomenon. Through various filtering/ thresholding techniques, it was found that the original signals were getting filtered out along with noise. Wavelet transformation technique is found to be more appropriate to analyse the AE signals under such situations. Wavelet transformation technique is used to de-noise the AE data. The de-noised signal is classified to identify a signature based on the type of phenomena.Defence Science Journal, 2008, 58(4), pp.559-564, DOI:http://dx.doi.org/10.14429/dsj.58.167

Dynamic refining control model for LD converter

A mathematical model for the dynamic refining control of the LD Converter is presented. Equations representing the reaction kinetics are formulated using the oxygen demand function. The amount of oxygen accumulated in LD Conver-ter, which is calculated from the oxygen balance by using exhaust gas data, corresponds to the amount of FeO, Fe203 and Mn0 in the slag during blowing. With the control of the refining reaction with oxygen balance carbon, phospho-rus and manganese contents of steel and the total iron content of slag at blow end were controlled at preferable levels and their fluctuations were remarkably reduced. The equations were coupled with appropriate thermal balance equations. The resulting set of non-linear first order equations have been numerically solved to predict the reaction path in the converter as a function of the operat-ing conditions like oxygen blowing rate, lance height, iron ore, limestone additions rates etc. With continuous on line data feeding from the converter facilities like sublance systems and waste gas analysers the entire conve-rter operation could be automated. The model works on a simple micro computer and could be easily incorporated on to the on-line control circuit of the Converter

Evidence for Oriented Adsorption in the Monolayers of Glassy Silica Gel & Fibrous Silica Gel (Santocel C)

553-55

Snow cover, snowmelt and runoff in the Himalayan River basins

Not withstanding the seasonal vagaries of both rainfall amount and snowcover extent, the Himalayan rivers retain their basic perennial character. However, it is the component of snowmelt yield that accounts for some 60 to 70 percent of the total annual flow volumes from Hamilayan watersheds. On this large hydropotential predominantly depends the temporal performance of hydropower generation and major irrigation projects. The large scale effects of Himalayan snowcover on the hydrologic responses of a few selected catchments in western Himalayas was studied. The antecedent effects of snowcover area on long and short term meltwater yields can best be analyzed by developing appropriate hydrologic models forecasting the pattern of snowmelt as a function of variations in snowcover area. It is hoped that these models would be of practical value in the management of water resources. The predictability of meltwater for the entire snowmelt season was studied, as was the concurrent flow variation in adjacent watersheds, and their hydrologic significance. And the applicability of the Snowmelt-Runoff Model for real time forecast of daily discharges during the major part of the snowmelt season is examined

Investigation of ultrasonic velocities in liquids by a new method

The principle and the experimental details of the new method of determining ultrasonic velocities in transparent liquids along with a brief description of the crystal holder designed to suit this method are given. Ultrasonic velocities determined for about ten common liquids are tabulated along with those obtained previously by different methods. The main features of this method are briefly discussed

Temperature dependent study of thermophysical properties of binary mixtures of 1,4-butanediol + picolines

The experimental values of densities (r) and speeds of sound (u) of (1,4-butanediol + α-, orβ- picoline) binary mixtures have been used to calculate the internal pressure (πi), free volume (Vf), enthalpy (H), entropy (Ts), excess internal pressure (πiE), excess free volume (VfE), excess enthalpy (HE), excess free energy (GE) and excess entropy (TsE) at temperatures 303.15, 308.15, 313.15 and 318.15K over the entire composition range. The results have been discussed in terms of molecular interactions due to physical, chemical and structural effects between the unlike molecules. It has been observed that the strength of intermolecular interaction between 1,4-butanediol and picoline molecules is in order ɑ-picoline>β-picoline

Study of the Topology Mismatch Problem in Peer-to-Peer Networks

The advantages of peer-to-peer (P2P) technology are innumerable when compared to other systems like Distributed Messaging System, Client-Server model, Cloud based systems. The vital advantages are not limited to high scalability and low cost. On the other hand the p2p system suffers from a bottle-neck problem caused by topology mismatch. Topology mismatch occurs in an unstructured peer-to-peer (P2P) network when the peers participating in the communication choose their neighbors in random fashion, such that the resultant P2P network mismatches its underlying physical network, resulting in a lengthy communication between the peers and redundant network traffics generated in the underlying network[1] However, most P2P system performance suffers from the mismatch between the overlays topology and the underlying physical network topology, causing a large volume of redundant traffic in the Internet slowing the performance. This paper surveys the P2P topology mismatch problems and the solutions adapted for different applications