ARTICLE | doi:10.20944/preprints202203.0389.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: Micro-grids; Droop Controls; Tap Changers; Islanded Mode; AC OPF; Lagrangian Relaxation; Renewable Generation; Markov Process; Mixed-Integer Nonlinear Programming
Online: 30 March 2022 (10:20:43 CEST)
Micro-grids’ operations offer local reliability; in the event of faults or low voltage/frequency events on the utility side, micro-grids can disconnect from the main grid and operate autonomously while providing the continued supply of power to local customers. With the ever-increasing penetration of renewable generation, however, the operations of micro-grids become increasingly complicated because of the associated fluctuations of voltages. As a result, transformer taps are adjusted frequently, thereby leading to the fast degradation of expensive tap-changer transformers. In the islanding mode, the difficulties also come from the drop of voltage and frequency upon disconnecting from the main grid. To appropriately model the above, the nonlinear AC power flow constraints are necessary. Computationally, the discrete nature of tap-changer operations and the stochasticity caused by renewables add two layers of difficulty on top of a complicated AC-OPF problem. To resolve the above computational difficulties, the main principles of the recently-developed "l1-proximal" Surrogate Lagrangian Relaxation are extended. Testing results based on 9-bus system demonstrate the efficiency of the method to obtain the exact feasible solutions for micro-grid operations thereby avoiding approximations inherent to existing methods, while demonstrating that through the optimization, 1. the number of tap changes is drastically reduced, and 2. the method is capable of handling networks with meshed topologies.
REVIEW | doi:10.20944/preprints202308.1553.v1
Online: 22 August 2023 (10:10:52 CEST)
Abstract: A punicalagin is a metabolic product of pomegranate fruits and peeled. We have compiled the recent literature review from different sources. The extract of pomegranate fruits and peel has been reported for health-beneficial properties in inflammation-associated chronic disease and the regulatory role in NF-KB, MAPK, IL-6/JAK/STAT3, and PI3K/AKT/mTOR signaling pathway. Punicalagin is an ellagitannin found in the peel of pomegranate (Punica granatum). It is a polyphenol with proven biological/pharmacological activities like antioxidant, hepatoprotective, an-ti-atherosclerotic, anti-cancer, anti-neurological, anti-diabetic, and anti-digestive. The extracts have a rich source of hydrolyzable tannin and anthocyanin exhibiting strong anti-neoplastic properties. Anti-cancer activities of pomegranate with reference to modulated signaling pathways in various cancer diseases have been recently reported. The punicalagin-induced redirection of the signal-transduction pathway from survival and proliferation into the cell cycle by arrested the living cells. Apoptosis senescence and autophagy and thus compromising neoplastic progression are delineated. This review is based mainly on data obtained from various sources including the in-vitro cell line model and its activities that are concerned with the effect of punicalagin activities on various cell types.