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1
Content available Performance Evaluation of a Zone-based Three-level Heterogeneous Clustering Protocol for WSNs
Rao Sanapala Shanmukha, Shilpi, Kumar Arvind
Journal of Telecommunications and Information Technology
|
2023
|
nr 3
85--93
EN
This paper proposes a zone-based three-level heterogeneous clustering protocol (ZB-TLHCP) for heterogeneous WSNs. In ZB-TLHCP, the sensor field/region is divided into zones where super, advance, and normal nodes are deployed uniformly and randomly. The performance of the proposed ZB-TLHCP system is compared with that of zonal-stable election protocol (Z-SEP), distributed energy efficient clustering (DEEC), and threshold-based DEEC (TDEEC) protocol by varying the number of super and advance nodes, their energy levels for the fixed sensor field, and the total number of nodes. Matlab simulation results revealed that the proposed ZB-TLHCP solution performed better than Z-SEP, DEEC, and TDEEC protocols, as it increased the instability period, prolonged the network's lifetime, and achieved higher throughput values.
2
Content available Electron Beam Processing of SensorsRelevant Vacoflux-49 Alloy: Experimental Studies of Thermal Zones and Microstructure
Kumar Pawan, Yadav Anshul, Kumar Arvind
Archives of Metallurgy and Materials
|
2020
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Vol. 65, iss. 3
1147--1156
EN
Vacoflux-49 (Fe-49% Co-49% V-2%) is used in torque, sonar and gyroscopic sensors applications due to excellent magnetic properties (high saturation magnetisation, low coercivity and high Curie temperature). In this study, the shape, size and characteristics of different thermal zones and the microstructural evolution during electron beam melting and welding of Vacoflux-49 material are studied. The experimental studies on melting have been carried out with under-focussed, focussed and over focussed electron beam. In the case of the under-focussed and over-focused beam, no evaporated zone is found. In the case of focussed beam, a shallow conical-shaped evaporated zone, a choked funnel-shaped fusion zone, a conical shaped partially melted zone and the heat-affected zone are observed. The solidified melt pool in terms of shape, size and microstructure of different zones are investigated for the focussed beam. The grains in the fusion zone appear wavy having crest and trough. The fusion zone microstructure also shows the formation of solidification rings. From the electron beam welding experiments performed for joining two Vacoflux-49 plates (continuous welding), it is found that the weldment shape is similar to the spot melting and re-solidification experiments. The grain growth in different zones in the welding sample is also examined.
3
Content available remote Mathematical study of Rayleigh waves in piezoelectric microstretch thermoelastic medium
Kumar Arvind, Abo-Dahab S. M., Ailawalia Praveen
Mechanics and Mechanical Engineering
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2019
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Vol. 23, nr 1
86--93
EN
This paper is concerned with the study of propagation of Rayleigh waves in a homogeneous isotropic piezo-electric microstretch-thermoelastic solid half-space. The medium is subjected to stress-free, isothermal boundary. After developing a mathematical model, the dispersion curve in the form of polynomial equation is obtained. Phase velocity and attenuation coefficient of the Rayleigh wave are computed numerically. The numerically simulated results are depicted graphically. Some special cases have also been derived from the present investigation.
4
Content available remote Elastodynamical disturbances due to laser irradiation in a microstretch thermoelastic medium with microtemperatures
Kumar Arvind, Singh Devinder
Mechanics and Mechanical Engineering
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2019
|
Vol. 23, nr 1
103--112
EN
This research is concerned with the study of mechanical disturbances due to presence of ultra-short laser pulse as input heat source in a microstretch thermoelastic medium with microtemperatures. The medium is subjected to normal and tangential forces. The solution of the problems is developed in terms of normal modes. Mathematical expressions have been obtained for normal stress, tangential stress, microstress and temperature change. The numerically computed results are shown graphically. A mathematical model has been developed and various stress quantities have been analyzed. Some particular cases are also derived from the present investigation.
5
Content available remote X-ray photoelectron spectroscopy (XPS) study of Heusler alloy (Co2FeAl) interfaced with semiconductor (n-Si) structure
Kumar Arvind, Srivastava P. C.
Materials Science Poland
|
2019
|
Vol. 37, No. 1
116--121
EN
Layered magnetic heterostructures are very promising candidates in spintronics in which the influences of interfaces, surfaces and defects play a crucial role. X-ray photoelectron spectroscopy (XPS) study has been performed for studying in detail the chemical state and electronic structure of Co2FeAl (CFA) Heusler alloy interfaced with Si substrates. XPS survey scan spectra have clearly shown the presence of Fe, Co and Al signal along with the signal due to Si. The presence of Co, Fe and Al signal confirms the formation of CFA alloy phase. Our XPS results support our previous study [1] on CFA/Si structure in determining the magnetic and transport properties across the interface.
6
Content available Influence of Dispersion Methods on the Mechanical, Thermal and Rheological Properties of HTPB-based Nanocomposites: Possible Binders for Composite Propellants
Ghosh Kavita, Kumar Arvind, Banerjee Shaibal, Patro Uma Sankar, Gupta Manoj
Central European Journal of Energetic Materials
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2019
|
Vol. 16, no. 2
281--298
EN
The present study reports on the methods of preparation for HTPB-clay nanocomposites and their mechanical, thermal and rheological properties for their functional utility as an improved binder system for composite propellants. HTPB-clay nanocomposites were prepared by dispersing organoclay Cloisite 30B (1-3 wt.%) in the polymer matrix by magnetic stirring and high shear mixing. Critical parameters like time, temperature and RPM were optimized. These nanocomposites were cured with toluene diisocyanate in the presence of the cure catalyst DBTDL. The dispersion of the nanoclay was evaluated by using small angle X-ray scattering (SAXS) and energy dispersive X-ray (EDX) spectroscopy. EDX suggested homogeneous distribution while SAXS revealed partial exfoliation of the clay particles in the polymer matrix. Superior dispersion of the nanoclay was obtained by high shear mixing. The tensile properties of the nanocomposites prepared by high shear mixing showed 10-20% more strength and elastic modulus. The nanocomposites showed thermal stability higher than the pristine HTPB. Swelling behavior revealed increased cross linking, and the rheological behavior exhibited higher viscosity of the nanocomposites. In addition, the clay amount was increased up to 10 wt.% and its effect on the mechanical, thermal and swelling behavior was observed. Theoretical performance predictions of composite propellants with nanocomposites revealed their possible functional utility.
7
Content available remote Analysis of Saturated Synchronous Machine considering d-q Axis Coupling Reactance
Singh Bharat, Chandel Aswani Kumar, Kumar Arvind
Annals of Computer Science and Information Systems
|
2017
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Vol. 10
329--334
EN
The present paper describes a study of small signal performance of synchronous machines connected to a large power system network through transmission line under steady-state operation by considering influence of saturation with cross-magnetizing phenomenon between d- and q-axis circuits. In the method, mutual reactance due to the cross magnetizing phenomenon can be consider on the basis of d-q axis magnetic field analysis. The quantitative accuracy requires the magnetic coupling between d- and q-axis circuits be considered. Subsequently, steady-state reactances are analyzed by considering mutual reactances due to cross magnetizing phenomenon. Synchronous machines have a nonlinear characteristic due to saturations and cross-magnetization phenomena, so that d-q axes inductances vary depending on the current amplitude and the load angle. Therefore, usually the uncoupled d-q model with constant parameters might not be suitable to represent accurately the performance of the electrical machine.
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