Formal specification of a self-sustainable holonic system for smart electrical micro-grids

Stand-alone micro-grids have emerged within the smart grids field, facing important challenges related to their proper and efficient operation. An example is the self-sustainability when the micro-grid is disconnected from the main utility, e.g., due to a failure in the main utility or due to geographical situations, which requires the efficient control of energy demand and production. This paper describes the formal specification of a holonic system architecture that is able to perform the automation control functions in electrical stand-alone micro-grids, particularly aiming to improve their self-sustainability. The system aims at optimizing the power flow among the different electrical players, both producers and consumers, to keep the micro-grid operating even under adverse situations. The behaviour of each individual holon and their coordination patterns were modelled, analysed and validated using the Petri net formalism, allowing the complete verification of the system correctness during the design phase.info:eu-repo/semantics/publishedVersio

Age estimation based on pulp–tooth volume ratio of anterior teeth in cone-beam computed tomographic images in a selected population: A cross-sectional study

The present study aimed to investigate the correlation between chronological age and pulp– tooth volume ratio in anterior teeth using cone beam computed tomographic (CBCT) images and provide equations for age estimation based on pulp–tooth volume ratio. In this cross-sectional study, CBCT images of 312 anterior teeth of the maxilla and mandible were examineαd. The chronological age and the sex of the patients were recorded. Tooth volume and pulp volume of the anterior teeth were measured using Mimics software, and then tooth–pulp volume ratio was calculated. Statistical analysis of data was performed using chi-square test, independent T-test, Pearson’s correlation, and linear regression (α = 0.05). Finally, equations were made based on the results of the regression analysis for age estimation in general and for males and females. The age of the subjects ranged between 16 and 69 years (mean 40.6 ± 12.74). The pulp–tooth volume ratio of the maxillary teeth was generally higher than the mandibular teeth. A significant inverse relationship between age and pulp–tooth volume ratio was observed for all anterior teeth. (p < 0.05). The strongest correlation between age and pulp–tooth volume ratio was reported for mandibular central incisor (r = −0.58, p < 0.001) and the weakest was for mandibular lateral incisor (r = −0.36, p = 0.012). Age estimation was most accurate among females using the maxillary central incisors (p < 0.001) and among males using the mandibular central incisors and maxillary canines (p = 0.003). Pulp–tooth volume ratio of mandibular central incisors, maxillary lateral incisors, and maxillary canines in males and maxillary and mandibular central incisors, maxillary lateral incisors, and maxillary and mandibular canines in females can be used for age estimation

A probabilistic method for the operation of three-phase unbalanced active distribution networks

YesThis paper proposes a probabilistic multi-objective optimization method for the operation of three-phase distribution networks incorporating active network management (ANM) schemes including coordinated voltage control and adaptive power factor control. The proposed probabilistic method incorporates detailed modelling of three-phase distribution network components and considers different operational objectives. The method simultaneously minimizes the total energy losses of the lines from the point of view of distribution network operators (DNOs) and maximizes the energy generated by photovoltaic (PV) cells considering ANM schemes and network constraints. Uncertainties related to intermittent generation of PVs and load demands are modelled by probability density functions (PDFs). Monte Carlo simulation method is employed to use the generated PDFs. The problem is solved using ɛ-constraint approach and fuzzy satisfying method is used to select the best solution from the Pareto optimal set. The effectiveness of the proposed probabilistic method is demonstrated with IEEE 13- and 34- bus test feeders

Differential metabolic effects of oral butyrate treatment in lean versus metabolic syndrome subjects

Background: Gut microbiota-derived short-chain fatty acids (SCFAs) have been associated with beneficial metabolic effects. However, the direct effect of oral butyrate on metabolic parameters in humans has never been studied. In this first in men pilot study, we thus treated both lean and metabolic syndrome male subjects with oral sodium butyrate and investigated the effect on metabolism. Methods: Healthy lean males (n = 9) and metabolic syndrome males (n = 10) were treated with oral 4 g of sodium butyrate daily for 4 weeks. Before and after treatment, insulin sensitivity was determined by a two-step hyperinsulinemic euglycemic clamp using [6,6-2H2]-glucose. Brown adipose tissue (BAT) uptake of glucose was visualized using 18F-FDG PET-CT. Fecal SCFA and bile acid concentrations as well as microbiota composition were determined before and after treatment. Results: Oral butyrate had no effect on plasma and fecal butyrate levels after treatment, but did alter other SCFAs in both plasma and feces. Moreover, only in healthy lean subjects a significant improvement was observed in both peripheral (median Rd: from 71 to 82 μmol/kg min, p < 0.05) and hepatic insulin sensitivity (EGP suppression from 75 to 82% p < 0.05). Although BAT activity was significantly higher at baseline in lean (SUVmax: 12.4 ± 1.8) compared with metabolic syndrome subjects (SUVmax: 0.3 ± 0.8, p < 0.01), no significant effect following butyrate treatment on BAT was observed in either group (SUVmax lean to 13.3 ± 2.4 versus metabolic syndrome subjects to 1.2 ± 4.1). Conclusions: Oral butyrate treatment beneficially affects glucose metabolism in lean but not metabolic syndrome subjects, presumably due to an altered SCFA handling in insulin-resistant subjects. Although preliminary, these first in men findings argue against oral butyrate supplementation as treatment for glucose regulation in human subjects with type 2 diabetes mellitus

A Distributed Feedback Control Approach to the Optimal Reactive Power Flow Problem

We consider the problem of exploiting the microgenerators connected to the low voltage or medium voltage grid in order to pro-vide distributed reactive power compensation in the power distribution network, solving the optimal reactive power flow problem for the mini-mization of power distribution losses subject to voltage constraints. The proposed strategy requires that all the intelligent agents, located at the generator buses, measure their voltage and share these data with the other agents via a communication infrastructure. The agents then adjust the amount of reactive power injected into the grid according to a policy which is a specialization of duality-based methods for constrained con-vex optimization. Convergence of the algorithm to the configuration of minimum losses and feasible voltages is proved analytically. Simulations are provided in order to demonstrate the algorithm behavior, and the innovative feedback nature of such strategy is discussed