North Eastern Regional Institute of Science and Technology

About: North Eastern Regional Institute of Science and Technology is a education organization based out in Itanagar, India. It is known for research contribution in the topics: Population & Raman spectroscopy. The organization has 813 authors who have published 1429 publications receiving 16122 citations.

Dielectric properties of a highly polar liquid crystalline material showing various types of layered structures

Abstract: Liquid crystal compound N-(4-n-pentyloxybenzalidene) 4′-n-pentylaniline is very interesting because of its rich phase variant, i.e. nematic, smectic A, smectic C, smectic F and smectic G phases. In the present work, temperature- and frequency-dependent dielectric studies on this compound in the homeotropic and planar orientation of molecules have been carried out in the frequency range of 1 Hz–10 MHz. The compound shows negative dielectric anisotropy (i.e. Δe < 0). Dielectric studies have shown three relaxation modes of different origin in various phases of the material. Relaxation frequencies of the observed modes follow Arrhenius behaviour. The relaxation due to interfacial polarisation, i.e. Maxwell–Wagner–Sillars effect has been observed in the nematic and isotropic phases. A relaxation mode due to the fluctuation of molecular tilt resembling the soft mode has been detected in the smectic A phase with pre- and post-transitional effects. Another mode due to the fluctuation of molecules about th...

Solid-state thermal decomposition of heterobimetallic oxalate coordination compounds, zinc(II)tetraaquatris(oxalato)lanthanate(III)hexahydrate and cadmium(II)heptaaquatris(oxalato)lanthanate(III)tetrahydrate

Abstract: Two heterobimetallic oxalate coordination compounds, zinc(II)tetraaquatris(oxalato)lanthanate(III)hexahydrate (ZnOLa) and cadmium(II)heptaaquatris(oxalato)lanthanate(III)tetrahydrate (CdOLa) were synthesized and characterized by elemental analysis, IR, electronic spectral and powder X-ray diffraction studies. Both the compounds were found to have monoclinic structure. Thermal decomposition studies by TG, DTG and DTA in air have proved that the aqua ligands are associated with metals in a stronger coordination mode. The temperatures for pyrolysis were adopted from the TG results chosen from the stable range of thermograms. In case of ZnOLa, it decomposes through two steps and the end product at 1000 °C was found to be consisting of mainly, La2O3, ZnO and La2ZnOx through the intermediate formation of several oxycarbonates of lanthanum at ca. 525 °C. In case of cadmium analogue, three steps decomposition were observed and the final products were confirmed as CdO2, La2O3, LaCO and La2CdOx via the formation of several intermediates at 340 and 590 °C. The La2C3 and carbon are also found as part of the end product. The kinetic parameters, E*, lnko, ∆H# and ∆S# of all the deaquated and decomposition steps are investigated and discussed from the DSC study in nitrogen.

Self-bearing switched reluctance motor: A review

Abstract: A switched reluctance motor is a variable speed motor in which switching of current results in the production of torque and power. Due to the doubly salient structure of switched reluctance motor high acoustic noises and vibrations are produced along with torque ripple. In order to overcome these hindrances bearing-less switched reluctance motor was introduced as a solution to this problem. The motoring action of a switched reluctance motor can be combined with a magnetic bearing action to get a single unit called self-bearing switched reluctance motor. It is an electromagnetic device that has the capability of supporting the rotor on its own, generating magnetic forces by the windings on its stator. This paper presents an extensive literature survey on self-bearing switched reluctance motor and its recent developments including its various purposes in industrial applications. Details of its working principle, design methodologies, winding designs, control strategies and some prototype developments have been studied and presented.

Integrated fuzzy-PI controlled current source converter based D-STATCOM

Abstract: The distribution static synchronous compensator (D-STATCOM) is a shunt-connected current injection custom power (CP) device that can be used for improving quality and reliability of the power supplied to electric consumers under dynamic conditions of the distribution system. The CP devices such as dynamic voltage restorer and unified power quality conditioner including D-STATCOM are mostly designed and implemented using voltage source converter topology. The performance of D-STATCOM can be improved, if it is realized by using a current source converter topology which can generate a controllable current directly at its output terminals. Although the current source converter (CSC) topology offers many promising advantageous features, not much research publications with CSC-based approach in the field of CP devices has been reported over the last one decade. This paper presents a novel method of realizing a D-STATCOM using CSC topology with an integrated fuzzy-PI controller for not only mitigating vo...