Search

Conventional Maximum Power Point Tracking (MPPT) controllers in photovoltaic (PV) systems are seen to achieve tracking speeds in range of milliseconds. Power-electronic circuits in these systems many-a-time demand faster control actions in microseconds, as they operate at high frequencies, and also, a delay in control action would lead to a corresponding power-loss. Hence, an MPPT controller delivering such fast tracking speeds would improve overall system performance. In this work, an Field Programmable Gate Array (FPGA) based Statechart Controller is developed to perform MPPT control of the PV system. The developed Statechart Controller is tested using software-in-the-loop simulation(SILS) and results are presented. With inputs from a programmable logic controller emulating PV characteristic curves, the Statechart Controller is then deployed in a target FPGA. A comparison between performance with conventional MPPT controller and Statechart Controller is presented and results indicate that the latter is more effective in terms of tracking speeds, determinism, and modularity. [ABSTRACT FROM AUTHOR]

Precision application of nutrient based on soil test value is important for improving nutrient use efficiency and yield of hybrid castor. Field trial was conducted during 2021 at Tapioca and Castor Research Station, Yethapur, Salem District, Tamil Nadu, India (110 ∘ 35' N, 780 ∘ 29' E). Fertilizer prescription equations (FPEs) were developed for hybrid castor by adopting inductive cum targeted yield model approach under irrigated condition on Alfisol. Initially, soil fertility gradients were established with respect to soil available N, P and K nutrients, and 24 treatments were imposed in three fertility strips under factorial randomized design. Principle component analysis revealed that all the variables accounted for developing the FPEs of hybrid castor are present at the positive quadrant which mean that all the variables are highly important toward the castor seed yield production. From the field experimental data, the basic parameters [nutrient requirement (NR) and nutrients contributions from farmyard manure (Co), fertilizer (Cf), and soil (Cs)] were computed. The nutrient required for producing one quintal of hybrid castor seed yield was evaluated as 3.20 kg of nitrogen, 1.23 kg of phosphorus pentoxide (P2O5), and 3.28 kg of potassium oxide (K2O). The study revealed that soil nutrient contribution was high in case of available phosphorus (41.87%), available nitrogen (21.56%), and available potassium (19.12%), respectively, toward P, N, and K nutrient uptake by hybrid castor. The nutrient contribution from farmyard manure (Co) toward the total uptake was 21.40% of N, 10.35% of P2O5, and 26.06% of K2O, respectively. FPEs for hybrid castor and a ready reckoner of fertilizer dosages were developed using basic data for operational range of soil test values for intended yield target under inorganic fertilization alone and Integrated plant Nutrient System (IPNS) (NPK and FYM). [ABSTRACT FROM AUTHOR]

The fertilizer prescription equations were developed for rainfed Bt cotton on Pielamedu series (Typic haplusterts) by adopting the inductive cum targeted yield model, and fertilizer requirements were quantified for Bt cotton based on soil test and yield target. The validity of fertilizer prescription equations was done by conducting test verification trials at four locations in Perambalur district of Tamil Nadu developed for rainfed Bt cotton. The fertilizer prescription equations were used to calculate the fertilizer doses for STCR treatments. The percent achievement of the targeted yield was within ±10% variation in all the locations for both the yield targets under nitrogen, phosphorus, and potassium (NPK) alone and IPNS, proving the validity of the equations. STCR-IPNS based fertilizer recommendations for a yield target of 32 q/ha has recorded the highest yield, nutrient response ratio, and percent yield achievement in all the locations. [ABSTRACT FROM AUTHOR]

The effect of annealing on microstructure, crystal structure, martensitic transformation temperature, and magnetization of the as-prepared and annealed Ni-Mn-Ga alloy has been investigated. The present study infers that annealing stabilizes the microstructure and reduces the range of martensitic transformation temperature and improves the magnetic properties of the Ni-Mn-Ga ferromagnetic shape memory alloys. Also, the result presented here shows that coexisting austenite and martensite phases in the as-prepared specimen are separated upon annealing. As the magnetic hysteresis of Ni49.5Mn29.3Ga21.2alloy is very narrow, the potential utilization of this composition may be expected in micro-actuators. [ABSTRACT FROM PUBLISHER]

Zinc oxide nanoparticles have been synthesized at room temperature and at 50°C via precipitation method for the present study. The effect of synthesis temperature on the crystalline size, microstructure, optical properties, and energy gap of the synthesized zinc oxide nanoparticles has been investigated. The particle size was found to reduce from 26 nm to 17 nm when the reaction temperature was increased from room temperature to 50°C. Energy gap of the prepared samples has been theoretically determined using effective mass model equation and compared with the experimental value. It depicts that the energy gap of the smaller nanoparticles is higher than the bigger one. The recorded blue shift confirmed the quantum confinement effect. Compositional quality and functional group of the zinc oxide nanoparticles have been studied, and the frequency of zinc oxide nanoparticles has been observed at two different regions, 566 cm−1 and 432 cm−1. The recorded ultraviolet-visible spectrum shows absorption peaks at 361 nm and 328 nm, which are less than the absorption peak of bulk zinc oxide (388 nm). Peak absorption wavelength measurement shows the average size of the prepared zinc oxide nanoparticles is as small as 1.55 nm. [ABSTRACT FROM AUTHOR]

Field experiments were conducted on a Typic Haplustalf soil of Tamil Nadu by adopting the inductive cum targeted yield model, and fertilizer requirements were quantified for beetroot based on soil test and yield target. The basic parameters [nutrient requirement (NR) and contributions of nutrients from soil (Cs), fertilizer (Cf), and vermicompost (Cvermi)] were computed from the field experimental data. Using these basic parameters, we developed fertilizer prescription equations under the integrated plant nutrition system (IPNS), and nomograms were formulated for the desired yield target of beetroot for a range of soil test values. The quantity of fertilizers that could be contributed by vermicompost at 5 t ha-1 was evaluated as 40, 21, and 30 kg nitrogen (N), phosphorus pentoxide (P2O5), and potassium oxide (K2O), respectively, when applied along with the NPK fertilizers as per soil test and desired yield target. [ABSTRACT FROM AUTHOR]

The ultrasonic velocity ( U ), density (ρ) and viscosity (η) of solutions containing equimolar concentration of four cycloalkanones (cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone) and Tetrachloroethylene (TCE) in n -hexane solutions have been measured at five different temperatures in the range 293-313 K. Acoustical parameters such as adiabatic compressibility (β), Rao constant (R), absorption coefficient (α/ f 2 ), free energy of activation (Δ G *), internal pressure (π i ), cohesive energy (CE), free volume ( V f ), molecular interaction parameter with respect to ultrasonic velocity ( X u ), density ( X ρ ), and viscosity ( X η ) were calculated from the experimental data. Formation constant ( K ) values of the charge transfer (CT) complexes have been evaluated using a modified Bhat equation. Thermodynamic parameters such as free energy change (Δ G ), enthalpy change (Δ H ), and entropy change (Δ S ) for the formation of these complexes are computed from the variation of formation constant values with temperature. The stability constants of the charge transfer complexes formed between four cyclicketones and TCE correlate satisfactorily with polarisability (α), and ionization potential (IP) values of the ketones. [ABSTRACT FROM AUTHOR]