Performance comparison of multicell series and npc multilevel сonverters for a statcom

Abstract. In this paper, we present a comparative study of the performances of the multicells series and the Neutral-Point-Clamped (NPC) three-level converters used at synchronous staticcompensators (STATCOM) for the control of the voltage at a point of the network. The analysis consists on a mathematical modeling, a pulse width modulation (PWM) control algorithm application and a simulation using the Matlab Simulink environment. The simulation results obtained show that the STATCOM allows the regulation of the voltage at the point of common coupling (PCC) by acting the reactive energy that it can supply or absorb.В статье представлено сравнительное исследование характеристик многоэлементных последовательных и трехуровневых преобразователей со связанной нейтральной точкой, используемых в синхронных статических компенсаторах (STATCOM) для управления напряжением в точке сети. Анализ основан на математическом моделировании, алгоритме управления с широтно-импульсной модуляцией (ШИМ) и моделировании с использованием среды Matlab Simulink. Полученные результаты моделирования показывают, что STATCOM позволяет регулировать напряжение в точке общей связи действием реактивной энергии, которую он способен подавать или поглощать

Nonthermal acceleration radiation of atoms near a black hole in presence of dark energy

We investigate how dark energy affects atom-field interaction. To this end, we consider acceleration radiation of a freely falling atom close to a Schwarzschild black hole (BH) in the presence of dark energy characterized by a positive cosmological constant $\Lambda$. The resulting spacetime is endowed with a BH and a cosmological (or de Sitter) horizon. Our consideration is a \textit{nonextremal} $(1+1)$-dimensional geometry with horizons far apart, giving rise to a flat Minkowski-like region in between the two horizons. Assuming a scalar ($\text{spin}-0$) field in a Boulware-like vacuum state, and by using a basic quantum optics approach, we numerically achieve excitation probabilities for the atom to detect a photon as it falls toward the BH horizon. It turns out that the nature of the emitted radiation deeply drives its origin from the magnitude of $\Lambda$. In particular, radiation emission is enhanced due to dilation of the BH horizon by dark energy. Also, we report an oscillatory nonthermal spectrum in the presence of $\Lambda$, and these oscillations, in a varying degree, also depend on BH mass and atomic excitation frequency. We conjecture that such a hoedown may be a natural consequence of a constrained motion due to the bifurcate Killing horizon of the given spacetime. The situation is akin to the Parikh-Wilzcek tunneling approach to Hawking radiation where the presence of extra contributions to the Boltzmann factor deforms the thermality of flux. It apparently hints at field satisfying a modified energy-momentum dispersion relation within classical regime of general relativity arising as an effective low energy consequence of an underlying quantum gravity theory. Our findings may signal new ways of conceiving the subtleties surrounding the physics of dark energy.Comment: 13 pages, 4 figure

Blockchain based Automated Construction Model Accuracy Prediction using DeepQ Decision Tree

A growth of Industry 4.0 standards are increasing day by day. Various research application and problem statements are coming to create multiple automation environments. Blockchain technology is the important evolution to produce dynamic and avoid intermediate middleware processing systems. In this paper we propose a blockchain based automated construction modelling and analysis system. Here we check the efficiency of the system by using collaboration, transparency, workflow and reliable data model. DeepQ based classification and prediction method is used to measure the accuracy index.  Decision tree algorithm is used to divide the process model and generate the chain codes. 1500 trained dataset and 750 dataset is taken from Revit construction model set and apply blockchain codes to process the dataset. The simulations are taken effectively and reach the accuracy as 96%

Dietary nitrate improves vascular function in patients with hypercholesterolemia: a randomized, double-blind, placebo-controlled study

Background: The beneficial cardiovascular effects of vegetables may be underpinned by their high inorganic nitrate content. Objective: We sought to examine the effects of a 6-wk once-daily intake of dietary nitrate (nitrate-rich beetroot juice) compared with placebo intake (nitrate-depleted beetroot juice) on vascular and platelet function in untreated hypercholesterolemics. Design: A total of 69 subjects were recruited in this randomized, double-blind, placebo-controlled parallel study. The primary endpoint was the change in vascular function determined with the use of ultrasound flow-mediated dilatation (FMD). Results: Baseline characteristics were similar between the groups, with primary outcome data available for 67 patients. Dietary nitrate resulted in an absolute increase in the FMD response of 1.1% (an ∼24% improvement from baseline) with a worsening of 0.3% in the placebo group (P 1% of this change, with the proportions of Rothia mucilaginosa trending to increase and Neisseria flavescens (P < 0.01) increased after nitrate treatment relative to after placebo treatment. Conclusions: Sustained dietary nitrate ingestion improves vascular function in hypercholesterolemic patients. These changes are associated with alterations in the oral microbiome and, in particular, nitrate-reducing genera. Our findings provide additional support for the assessment of the potential of dietary nitrate as a preventative strategy against atherogenesis in larger cohorts. This trial was registered at clinicaltrials.gov as NCT01493752

Laser-ultrasonic characterization of a zinc layer on a steel substrate using surface accoustic waves

Laser-ultrasonics and acoustic modeling were used to characterize the Lame coefficients (\u3bb, \u3bc) density (\u3c1) and thickness (h) of a zinc layer on a steel substrate. This characterization is based on fitting the measured velocity dispersion curve of surface acoustic waves (SAW) on a dispersion curve calculated using the conjugates gradients algorithm. The velocity dispersion curve of the Rayleigh wave was calculated in the frequency range of 1\u2013200 MHz and measurements were achieved from 5 to 50 MHz.Peer reviewed: YesNRC publication: Ye