A preliminary study on avifaunal species diversity of Maharaja Bir Bikram College campus, Tripura, North East India

Maharaja Bir Bikram College campus, Tripura is having a very good biodiversity having a different type of flora and fauna. The two big lakes and different types of flowering and fruit plants present in the campus provide grounds for feeding, breeding and nesting for avian fauna. The field survey was made to assess the campus avian faunal diversity by conducting weekly observations. Seventy six species of birds belonging to 42 families and 14 orders were recorded. Order Passeriformes contribute to about 42% of the total bird species richness. Of the total diversity, 51% birds are common, 22% are rare and 26% are abundant. Among the foraging groups, insectivores dominated the bird community

Dual observer based adaptive controller for hybrid drones

A biplane quadrotor (hybrid vehicle) benefits from rotary-wing and fixed-wing structures. We design a dual observer-based autonomous trajectory tracking controller for the biplane quadrotor. Extended state observer (ESO) is designed for the state estimation, and based on this estimation, a Backstepping controller (BSC), Integral Terminal Sliding Mode Controller (ITSMC), and Hybrid Controller (HC) that is a combination of ITSMC + BSC are designed for the trajectory tracking. Further, a Nonlinear disturbance observer (DO) is designed and combined with ESO based controller to estimate external disturbances. In this simulation study, These ESO-based controllers with and without DO are applied for trajectory tracking, and results are evaluated. An ESO-based Adaptive Backstepping Controller (ABSC) and Adaptive Hybrid controller (AHC) with DO are designed, and performance is evaluated to handle the mass change during the flight despite wind gusts. Simulation results reveal the effectiveness of ESO-based HC with DO compared to ESO-based BSC and ITSMC with DO. Furthermore, an ESO-based AHC with DO is more efficient than an ESO-based ABSC with DO.Web of Science71art. no. 4

Functionality analysis of electric actuators in renewable energy systems - A review

Various mechanical, hydraulic, pneumatic, electrical, and hybrid actuators can alter motion per the requirements of particular applications. However, except for electrical ones, all actuators are restricted due to their size, complex auxiliary equipment, frequent need for maintenance, and sluggish environment in renewable applications. This brief review paper highlights some unique and significant research works on applying electrical actuators to renewable applications. Four renewable energy resources, i.e., solar, wind, bio-energy, and geothermal energy, are considered to review electric actuators applicable to renewable energy systems. This review analyses the types of actuators associated with the mentioned renewable application, their functioning, their motion type, present use, advantages, disadvantages, and operational problems. The information gathered in this paper may open up new ways of optimization opportunities and control challenges in electrical actuators, thereby making more efficient systems. Furthermore, some energy-efficient and cost-effective replacements of convectional actuators with new innovative ones are suggested. This work aims to benefit scientists and new entrants working on actuators in renewable energy systems.Web of Science2211art. no. 427

Rotor failure compensation in a biplane quadrotor based on virtual deflection

A biplane quadrotor is a hybrid type of UAV that has wide applications such as payload pickup and delivery, surveillance, etc. This simulation study mainly focuses on handling the total rotor failure, and for that, we propose a control architecture that does not only handle rotor failure but is also able to navigate the biplane quadrotor to a safe place for landing. In this structure, after the detection of total rotor failure, the biplane quadrotor will imitate reallocating control signals and then perform the transition maneuver and switch to the fixed-wing mode; control signals are also reallocated. A synthetic jet actuator (SJA) is used as the redundancy that generates the desired virtual deflection to control the pitch angle, while other states are taken care of by the three rotors. The SJA has parametric nonlinearity, and to handle it, an inverse adaptive compensation scheme is applied and a closed-loop stability analysis is performed based on the Lyapunov method for the pitch subsystem. The effectiveness of the proposed control structure is validated using numerical simulation carried out in the MATLAB Simulink.Web of Science67art. no. 17

Transformer Oil Quality Diagnostic Using Spectroscopy Techniques - A Review

Transformer serves as a vital component in the electrical energy supply system. In order to have an uninterrupted power supply, it is essential to timely monitor the condition of the transformer. A transformer has many components, out of which the transformer oil is one of the most crucial. It provides insulation and keeps the transformer cool. With ageing, the quality of the transformer oil degrades, and it loses its insulation properties that become a threat to the supply system. Optical Spectroscopy has gained a lot of attention in monitoring the quality of transformer oil in the past few years for various advantages. This paper reviews some of the commonly applied Spectroscopy techniques to monitor the various components of transformer oil by which we can predict the quality of the oil

Seasonal variation of evapotranspiration and its effect on the surface energy budget closure at a tropical forest over north-east India

This study uses one year of eddy covariance flux observations to investigate seasonal variations in evapotranspiration and surface energy budget closure at a tropical semi-deciduous forest located in north east India. The annual cycle is divided into four seasons, namely: pre-monsoon, monsoon, post-monsoon, and winter. The highest energy balance closure (76%) is observed during pre-monsoon, whereas the lowest level of closure (62%) is observed during winter. Intermediate closure of 68% and 72% is observed during monsoon and post-monsoon seasons, respectively. Maximum latent heat flux during winter (150 W m-2) is half of the maximum latent heat (300 W m-2) flux during monsoon. Evapotranspiration is a controlling factor of surface energy budget closure, with highest rates of closure corresponding to the periods of highest evapotranspiration. The Bowen ratio ranges from 0.93 in winter to 0.27 during monsoon. This is the first time the role of evapotranspiration in the seasonal variation of surface energy budget closure has been reported for any ecosystem in north-east India using eddy covariance measurements

Wind turbine gearbox condition monitoring based on class of support vector regression models and residual analysis

The intelligent condition monitoring of wind turbines reduces their downtime and increases reliability. In this manuscript, a feature selection-based methodology that essentially works on regression models is used for identifying faulty scenarios. Supervisory control and data acquisition (SCADA) data with 1009 samples from one year and one month before failure are considered. Gearbox oil and bearing temperatures are treated as target variables with all the other variables used for the prediction model. Neighborhood component analysis (NCA) as a feature selection technique is employed to select the best features and prediction performance for several machine learning regression models is assessed. The results reveal that twin support vector regression (99.91%) and decision trees (98.74%) yield the highest accuracy for gearbox oil and bearing temperatures respectively. It is observed that NCA increases the accuracy and thus reliability of the condition monitoring system. Furthermore, the residuals from the class of support vector regression (SVR) models are tested from a statistical point of view. Diebold–Mariano and Durbin–Watson tests are carried out to establish the robustness of the tested models