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.

Current source converter based D-STATCOM for voltage sag mitigation

Abstract: This paper presents a novel method of realizing one of the custom power controllers, the distribution static synchronous compensator (D-STATCOM) using current source converter (CSC) topology. Almost all the custom power controllers such as dynamic voltage restorer (DVR), unified power quality conditioner (UPQC) including D-STATCOM are generally designed and implemented by using voltage source converters (VSC) and not much research publications with CSC based approach has been reported over the last one decade. Since the D-STATCOM is a current injection device, its performance can be improved when realized by a current-source converter which can generate a controllable current directly at its output terminals and offers many advantageous features. In this paper, an attempt has been made to study the performance of a CSC based D-STATCOM suitable for use in the power distribution system in order to mitigate voltage sag and improve power quality. The proposed model uses a three leg CSC whose switching strategy is based on sinusoidal pulse width modulation (SPWM). The model has been simulated in the Matlab/Simulink environment. The results of the simulation runs under steady state and dynamic load perturbation provide excellent voltage and current waveforms that support the justification of the proposed model.

Compact CPW-fed tri-band antenna with a defected ground structure for GSM, WLAN and WiMAX applications

Abstract: In this paper we propose and investigate a unique compact FR4 based CPW-fed tri-band antenna for wireless applications. The antenna comprises frequency shifting strips and a defected ground structure (formed by combining of metallic strips and cutting of an L-shaped slot from the ground). The proposed antenna provides three different impedance bandwidths of 0.57, 0.98 and 1.59 GHz which are sufficient to cover the frequency band of GSM 1800/1900, WLAN 5.5/5.8 GHz and WiMAX applications. The developed antenna has a size of 17-20 mm and operates over frequency ranges 1.50–2.08, 5.25–6.23 and 9.10–10.69 GHz centered at 1.702, 5.802 and 10.102 GHz, respectively. The antenna was designed and simulated using Ansoft HFSS software. The antenna’s characteristics such as reflection coefficient, radiation pattern, impedance bandwidth and VSWR are presented.

Significances of Fungi in Bioremediation of Contaminated Soil

Abstract: In the present time of excessive industrialization, huge pollutants are being released in our environment. These pollutants may be toxic metals/metal complexes, extremely harmful organic compounds, carcinogenic xenobiotics, petroleum wastes, polyaromatic hydrocarbons, fertilizers, agrochemicals, dyes, synthetic by-products, organic solvents, etc. They are highly dangerous in exposed form for our environment, animals, useful insects as well as human beings. Different organic chemicals, excessive use of fertilizers, agrochemicals, pesticides/insecticides, petroleum and petro-products, polyaromatic hydrocarbons, polluted sewage of industries, toxic metals, and many other xenobiotics pollute the soils. The pollution of soil of agricultural fields has given rise to many adverse effects. Fertility of soils and useful insects of soils are being reduced and destroyed due to such pollutants, which will further reduce the agricultural land. Furthermore, agricultural products obtained from contaminated soil contain various pollutants that may be extremely dangerous for human life because there accumulation in human bodies may create different abnormalities, skin diseases, abdominal diseases, etc. Thus, efforts for the green removal or detoxification of such pollutants are greatly required for the present scenario of excessive use of chemicals. Role of fungi have attained a distinguished status in the remediation of contaminated soils. In this regard, this chapter deals with comprehensive discussions and future aspects on the fate of the utilization of fungi in the remediation of contaminated soils.

Parametric Study of Sheet Pile Wall using ABAQUS

Abstract: In the present study two-dimensional finite element analysis has been carried out on cantilever sheet pile wall using ABAQUS/Standard software to study the effect of different friction angles and its related parameters such as dilation angle, the interfacial friction coefficient between soil-wall on earth pressure distribution, and wall deformation. From the results obtained, it is found that there is a significant decrease in wall deformation with an increase in the angle of internal friction and its related parameters. The earth pressure results obtained from the finite element analysis shared a unique relationship with that of a conventional method. Both the results showed similar linear behavior up to a certain percentage of wall height and then changed drastically in lower portions of the wall. This trend of behavior is seen in both active as well as in passive earth pressure distribution for all the frictional angle. Hence, after comparing the differences that exist in the results for both methods, from the analysis a new relationship between the earth pressure coefficients from a conventional method and the finite element method has been developed for both active and passive earth pressure on either side of the sheet pile wall. This relationship so derived can be used to compute more reasonable earth pressure distributions for a sheet pile wall without carrying out a numerical analysis with a minimal time of computation. And also the earth pressure coefficient calculated from this governing equation can serve as a quick reference for any decision regarding the design of the sheet pile wall. Doi: 10.28991/cej-2021-03091638 Full Text: PDF

Effect of simultaneous Ti and Nb doping on structure and ionic conductivity of Bi2V1−xTix/2Nbx/2O5.5−δ (0.1 ≤ x ≤ 0.25) ceramics

Abstract: Solid solution of general formula Bi2V1−xTix/2Nbx/2O5.5−δ (0.1 ≤ x ≤ 0.25) were synthesized and characterized by XRD, SEM, FTIR spectroscopy, and AC impedance spectroscopy. The detail XRD analysis reveals coexistence of two phases, i.e., β-orthorhombic and tetragonal at room temperature in these compounds. For lower x (˂ 0.15), β-orthorhombic phase dominates while at higher doping concentration tetragonal phase dominates with the optimum concentration of tetragonal phase for x = 0.15 composition. FTIR studies are in conformity with the observation of XRD results. SEM studies show decrease in average grain size with increase in dopants’ concentration. The impedance spectroscopy data were fitted with suitable equivalent circuit and circuit parameters were obtained. A correlation among crystal structure, surface morphology, and ionic conductivity was found. At low and intermediate temperature regime, highest conductivity was obtained for x = 0.15 and at high temperature region, it was for x = 0.1. The measured conductivity values are higher as compared to single doped Ti/Nb and parent compounds.