Load frequency control scheme for a microgrid system with the application of hTLO-DE algorithm

Load frequency control (LFC) is a crucial feature of electric power systems to maintain a balance between power supply and load demand, thus avoiding a deviation of the grid frequency. The present work aims to implement an effective LFC scheme for a microgrid system consisting of a diesel generator (DEG), a wind turbine generator (WTG) and a battery storage system. Proportional-integral-double-derivative (PIDD) controllers are used to implement the proposed LFC scheme. The controller parameters are computed using an innovative hybrid teaching-learning-optimization differential-evaluation (hTLO-DE) algorithm. The main scope of the work lies in application of hTLO-DE optimized PIDD controllers in DEG-WTG-battery storage based MG system. The results obtained with PIDD controllers are compared with those obtained with the traditional PI and PID controllers. A critical analysis shows that the PIDD controller can provide better dynamic responses in terms of settling time and magnitude of oscillations compared to PI and PID controllers. The frequency responses of the system are studied under different scenarios of generation and load variations, which establishes the robustness of the proposed PIDD-based LFC scheme

Magneto-dielectric effect in Pb(Zr_0·52Ti_0·48)O₃ filled nanoporous Ni_0·5Zn_0·5Fe₂O₄ composite

Nanoporous Ni0·5Zn0·5Fe2O4 particles of diameter, ~ 9·5 nm, were synthesized by citric acid assisted thermal decomposition in an autoclave. The BET surface area measured was 80 m2 g − 1 and the average pore diameter was 2·5 nm. By soaking the particles in a suitable precursor solution and then subjecting them to a heat treatment at 923 K for 3 h, Pb(Zr0·52Ti0·48)O3 was grown within the nanopores. X-ray and electron diffraction studies confirmed the presence of both these phases. The nanocomposites showed ferromagnetic behaviour over the temperature range 2–300 K. No ferroelectric hysteresis loop could be found which was consistent with the earlier theoretical prediction of loss of ferroelectricity below a critical thickness of 2·4 nm. Good magneto-dielectric response of the order of 7% at a magnetic field of 9 kOe was recorded for the present system. This is believed to arise due to a negative magnetostriction coefficient of Ni0·5Zn0·5Fe2O4 which exerted a compressive strain on Pb(Zr0·52Ti0·48)O3 thereby lowering the tetragonality in its crystal structure

Steer Guidance Of Autonomous Agricultural Robot Based On Pure Pursuit Algorithm And LiDAR Based Vector Field Histogram

The application of autonomous robots has been increasing in agriculture sector to substitute human labour and to improve the production yields. A self-sufficient robot is intended to accomplish specific jobs in different locations of the working field area, thereby an economical and effective navigation system for differential wheeled mobile robots is a paramount importance. In this paper, an autonomous navigation system of an agricultural mobile robot is proposed using pure pursuit algorithm (PPA) which is also assisted by vector field histogram (VFH). PPA autonomously guides towards waypoints, whereas the VFH algorithm helps the vehicle steer away for obstacles. The 2-dimensional light detection and ranging (LiDAR) sensors are used to monitor through the VFH algorithm. Minimum number of waypoints are set in PPA for convenience on map setup. Several indicators such as distance covered by robot, number of iterations required for completion of travel, etc., are investigated with the variable settings in PPA algorithm. Result analysis shows that mobile robot can travel at speed range of 2.5-25 km/hr with obstacle evasion which is adequate for agricultural mobile robots

Evaluation of the equivalence of different intakes of Fruitflow in affecting platelet aggregation and thrombin generation capacity in a randomized, double-blinded pilot study in male subjects

Background The water-soluble tomato extract, Fruitflow® is a dietary antiplatelet which can be used to lower platelet aggregability in primary preventative settings. We carried out a pilot study to investigate the range of intakes linked to efficacy and to make an initial assessment of variability in response to Fruitflow®. Methods Platelet response to adenosine diphosphate (ADP) agonist and thrombin generation capacity were monitored at baseline and 24 h after consuming 0, 30, 75, 150 or 300 mg of Fruitflow® in a randomized, double-blinded crossover study in male subjects 30–65 years of age (N = 12). Results were evaluated for equivalence to the standard 150 mg dose. Results Results showed that the changes from baseline aggregation and thrombin generation observed after the 75 mg, 150 mg, and 300 mg supplements were equivalent. Aggregation was reduced from baseline by − 12.9 ± 17.7%, − 12.0 ± 13.9% and − 17.7 ± 15.7% respectively, while thrombin generation capacity fell by − 8.6 ± 4.1%, − 9.2 ± 3.1% and − 11.3 ± 2.3% respectively. Effects observed for 0 mg and 30 mg supplements were non-equivalent to 150 mg and not different from baseline (aggregation changed by 3.0 ± 5.0% and − 0.7 ± 10.2% respectively, while thrombin generation changed by 0.8 ± 3.0% and 0.8 ± 3.1% respectively). Conclusions The data suggest that the efficacious range for Fruitflow® lies between 75 mg and 300 mg, depending on the individual. It may be pertinent to personalize the daily intake of Fruitflow® depending on individual platelet response. Trial registration ISRCTN53447583, 24/02/2021

An FPGA Kalman-MPPT implementation adapted in SST-based dual active bridge converters for DC microgrids systems

The design of digital hardware controllers for the integration of renewable energy sources in DC microgrids is a research topic of interest. In this paper, a Kalman filter-based maximum power point tracking algorithm is implemented in an FPGA and adapted in a dual active bridge (DAB) converter topology for DC microgrids. This approach uses the Hardware/Software (HW/SW) co-design paradigm in combination with a pipelined piecewise polynomial approximation design of the Kalman-maximum power point tracking (MPPT) algorithm instead of traditional lookup table (LUT)-based methods. Experimental results reveal a good integration of the Kalman-MPPT design with the DAB-based converter, particularly during irradiation and temperature variations due to changes in weather conditions, as well as a good balanced hardware design in complexity and area-time performance compared to other state-of-art FPGA designs

Sustainable Management of Phosphorus in Agriculture for Environmental Conservation

Phosphorus (P) is an essential macronutrient for plant growth and development. Although the P-concentration in soil is 1000 folds higher than in plants, it is rarely available for plant uptake due to low diffusion and high fixation rate in soil. Hence, plants experience P-deficiency in the absence of P-fertilization, which may cause approximately a 30–40% decrease in crop yield. This highlights the importance of using a large amount of phosphate fertilizers to meet crop demands. As P-fertilizer is derived from a nonrenewable and finite source of rock phosphate, this resource is decreasing over time. In addition, farmers are applying P-fertilizers randomly without considering the soil stock, which leads to the loss of P-resources. The low P-use-efficiency (PUE) of plants in the field condition (15–20%) highlights that most of the soil-applied P remains unavailable to plants, and excess P causes ground and surface water contamination (i.e., eutrophication) through leaching and runoff, which ultimately results in environmental pollution. Therefore, it is crucial to apply P-fertilizers considering the soil test value and PUE to protect the environment from contamination and sustainable management of P-resources. This chapter mainly focuses on the sustainable management of P in agricultural fields for environmental conservation

"The fruits of independence": Satyajit Ray, Indian nationhood and the spectre of empire

Challenging the longstanding consensus that Satyajit Ray's work is largely free of ideological concerns and notable only for its humanistic richness, this article shows with reference to representations of British colonialism and Indian nationhood that Ray's films and stories are marked deeply and consistently by a distinctively Bengali variety of liberalism. Drawn from an ongoing biographical project, it commences with an overview of the nationalist milieu in which Ray grew up and emphasizes the preoccupation with colonialism and nationalism that marked his earliest unfilmed scripts. It then shows with case studies of Kanchanjangha (1962), Charulata (1964), First Class Kamra (First-Class Compartment, 1981), Pratidwandi (The Adversary, 1970), Shatranj ke Khilari (The Chess Players, 1977), Agantuk (The Stranger, 1991) and Robertsoner Ruby (Robertson's Ruby, 1992) how Ray's mature work continued to combine a strongly anti-colonial viewpoint with a shifting perspective on Indian nationhood and an unequivocal commitment to cultural cosmopolitanism. Analysing how Ray articulated his ideological positions through the quintessentially liberal device of complexly staged debates that were apparently free, but in fact closed by the scenarist/director on ideologically specific notes, this article concludes that Ray's reputation as an all-forgiving, ‘everybody-has-his-reasons’ humanist is based on simplistic or even tendentious readings of his work