Optimal PID Tuning of PLL for PV Inverter Based on Aquila Optimizer

Phase-locked loop (PLL) is a fundamental and crucial component of a photovoltaic (PV) connected inverter, which plays a significant role in high-quality grid connection by fast and precise phase detection and lock. Several novel critical structure improvements and proportional-integral (PI) parameter optimization techniques of PLL were proposed to reduce shock current and promote the quality of grid connection at present. However, the present techniques ignored the differential element of PLL and did not acquire ideal results. Thus, this paper adopts Aquila optimizer algorithm to regulate the proportional-integral-differential (PID) parameters of PLL for smoothing power fluctuation and improving grid connection quality. Three regulation strategies (i.e., PLL regulation, global regulation, and step regulation) are carefully designed to systematically and comprehensively evaluate the performance of the proposed method based on a simulation model in MATLAB/Simulink, namely, “250-kW Grid-Connected PV Array”. Simulation results indicate that PLL regulation strategy can effectively decrease power fluctuation and overshoot with a short response time, low complexity, and time cost. Particularly, the Error(P) and the maximum deviation of output power under optimal parameters obtained by PLL strategy are decreased by 418 W and 12.5 kW compared with those under initial parameters, respectively.

The Determination of Metronidazole and Chlorhexidine Gluconate in Metronidazole and Chlorhexidine Lotion by HPLC

Objective “To establish an HPLC method for the determination of metronidazole and chlorhexidine gluconate in metronidazole and chlorhexidine lotion. Method Using Agilent Eclipse-XDB-C18 chromatographic column, with 0.05 mol·L-1 potassium dihydrogen phosphate solution 1000 ml plus 13.2 ml 10% tetrabutylammonium hydroxide aqueous solution (pH adjusted to 3.5 by phosphoric acid)-acetonitrile (77:23) as Mobile phase, detection wavelength 230 nm. Results The two components could be separated well. The linear ranges of metronidazole and chlorhexidine acetate were 36.33~59.04 μg·ml-1 (r = 0.9994) and 35.45~220.11 μg·ml-1 (r = 1).); The average recoveries were 100.6% and 100.5 %, and the RSD were 0.42% and 0.58%. Conclusion: The method is simple and specific, and the result is more accurate and reliable. Which is suitable for simultaneous determination of two components in compound preparations.

Impact of the isomerism of peptide mimetics on the assembly and properties: quick and onsite gas phase detection of acid and alcohols

The effect of isomerism on the structure, self-assembly and properties of two peptide mimetics has been investigated. The peptide mimetics contain m-aminobenzoic acid, p-aminobenzoic acid and N,N'-dicyclohexylurea. From X-ray crystallography,...

‘Aggregation-Induced Emission’ Active Mono-Cyclometalated Iridium(III) Complex Mediated Efficient Vapor-Phase Detection of Dichloromethane

Selective vapor-phase detection of dichloromethane (DCM) is a challenge, it being a well-known hazardous volatile organic solvent in trace amounts. With this in mind, we have developed an ‘Aggregation-induced Emission’ (AIE) active mono-cyclometalated iridium(III)-based (M1) probe molecule, which detects DCM sensitively and selectively in vapor phase with a response time < 30 s. It reveals a turn-on emission (non-emissive to intense yellow) on exposing DCM vapor directly to the solid M1. The recorded detection limit is 4.9 ppm for DCM vapor with pristine M1. The mechanism of DCM detection was explored. Moreover, the detection of DCM vapor by M1 was extended with a low-cost filter paper as the substrate. The DCM is weakly bound with the probe and can be removed with a mild treatment, so, notably, the probe can be reused.

A Validated HPTLC Densitometric Method for The Quantitative Determination of Ubidecarenone in Bulk and in Capsule Formulation

A new, simple, precise, accurate and rapid high performance thin layer chromatographic method has been developed and validated for the estimation of ubidecarenone in bulk and in capsule formulation. The chromatographic separation was performed on aluminium TLC plates precoated with silica gel 60F254 as a stationary phase and methanol:water (7:3) as a mobile phase. Detection was performed densitometrically in the absorbance mode at 280nm for the evaluation of chromatograms. The system has given well sharp peak of ubidecarenone (Rf=0.51±0.02). The linearity of the method was established in the range of 1-6 ng/µL with correlation coefficient (r2) of 0.9995. The method was validated for precision, accuracy, robustness, ruggedness, LOD, and LOQ as per ICH guidelines. The limit of detection was found to be 0.0392 ng/µL, whereas the limit of quantitation was found to be 0.1189 ng/µL. The percentage label claim for ubidecarenone in the capsule formulation was found to be 99.96±0.4703. The accuracy of the method was confirmed by recovery studies. The percentage recovery was found to be in the range of 100.10-101.45% for ubidecarenone. The % RSD value was found to be less than 2. The low %RSD value indicates that there is no interference due to excipients used in the formulation. Hence, the developed method was found to be simple, precise, accurate, and rapid for the analysis of ubidecarenone in bulk and pharmaceutical formulation and it can be effectively applied for the quality control analysis of ubidecarenone in bulk and pharmaceutical formulation.

Development of Validated RP-HPLC Method for Estimation of Empagliflozin and Metformin in Combined Formulation

Aim: The aim of the present study include development of validated RP-HPLC method for estimation of Empagliflozin and Metformin in combined dosage form by using LC-MS compatible volatile mobile phase. Methodology: Appropriate separation of drugs was achieved using C18 column as a stationary phase and Acetonitrile: Water (50: 50, v/v) at a flow rate 1mL/min as mobile phase. Detection was done at 230 nm. Results: The Rt of Metformin and Empagliflozin was found to be 2.20 ± 0.02 min and 3.64 ± 0.02 min respectively. When the marketed formulation was analyzed by the developed method, the % drug contents were found to be 98.57 ± 1.28 and 99.86 ± 1.02 %w /w for Empagliflozin and Metformin, respectively. The method was found to be linear in a range of 11.25 – 56.25 μg/mL for Empagliflozin and 85 – 425 μg/mL for Metformin. Detection limit and quantitation limit were found to be 0.30 and 0.92 μg/mL for Empagliflozin and 1.12 and 3.36 μg/mL for Metformin, respectively. The accuracy and precision results were found to be near 100 % w/w for both the drugs. The method was also found to be robust and specific. Conclusion: The developed RP-HPLC method was found to be linear, sensitive, accurate, precise, specific and robust for the analysis of Empagliflozin and Metformin in combined dosage form.

Referencing technique for phase detection in eddy current evaluation

This paper presents an eddy current testing (ECT) method with a different type of referencing technique for crack detection in carbon steel plate by using two Anisotropic Magnet Resistance (AMR) sensors to detect and evaluate the artificial cracks and to study the output signal's characteristics of each technique. The experiment setup of the magnetic scanning device and the measurement mode is included. Based on these three techniques that have been used, it shown that differential technique with the condition of the required reference signal must be dynamic from one point to one point was the best way to implement in the ECT method. The line scanning results indicate that performing these three techniques can be used to estimate the position of the slits, however, for 2-D mapping, it is shown that the differential technique is a preferable technique where it can remove the noise response, and at the same time, it generates a clear image of the crack. It is predicted that the developed ECT probe using a differential technique can be used as a technique to estimate the characteristic of defects in a metal plate.