Fuzzy logic energy management for a microgrid with storage battery

ABSTRACT

This article presents the development of an energy management system using fuzzy logic applied to a microgrid that combines photovoltaic solar energy, wind energy and a storage system with batteries. The model was developed using LabVIEW software and allows to obtain performance results of the photovoltaic generator, the wind turbine and the battery bank. The energy management system can be controlled in real time to take advantage of existing weather conditions. The results indicate that the fuzzy logic system guarantees the continuous operation of the load through the energy resources of the microgrid. The designed microgrid allows to generate 63,288?kWh/year of photovoltaic solar energy and 40,175?kWh/year of wind energy.     

Gravel deposits survey in south central Brazil

This paper deals with the influence of discontinuous particle-size distribution on the basic properties of asphaltic concrete. New particle-size curves were obtained by removing the fine, medium and coarse material connected with one or two successive sieves. Consequently the following characteristics have been examined: stability, deformation and voids of compacted asphaltic concrete according to the Greek specifications. The results showed that a high degree of flexibility capable of removing part of the aggregate exists. In that case the values of tests present positive or negative results which are also influenced by the existing proportion of bitumen. Thus a revision of specifications concerned with particle-size distribution might be possible.     

Nitrogen doping of SiC thin films deposited by RF magnetron sputtering

Silicon carbide thin films (Si _x C _y ) were deposited in a RF (13.56 MHz) magnetron sputtering system using a sintered SiC target (99.5% purity). In situ doping was achieved by introducing nitrogen into the electric discharge during the growth process of the films. The N₂/Ar flow ratio was adjusted by varying the N₂ flow rate and maintaining constant the Ar flow rate. The structure, composition and bonds formed in the nitrogen-doped Si _x C _y thin films were investigated by X-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), Raman spectroscopy and Fourier transform infrared spectrometry (FTIR) techniques. RBS results indicate that the carbon content in the film decreases as the N₂/Ar flow ratio increases. Raman spectra clearly reveal that the deposited nitrogen-doped SiC films are amorphous and exhibited C–C bonds corresponding to D and G bands. After thermal annealing, the films present structural modifications that were identified by XRD, Raman and FTIR analyses.     

Microscopic evidences that bone marrow mononuclear cell treatment improves sciatic nerve regeneration after neurorrhaphy

Cell therapy constitutes a possibility for improving nerve regeneration, increasing the success of nerve repair. We evaluate the use of mononuclear cells in the regeneration of the sciatic nerve after axotomy followed by end‐to‐end neurorrhaphy. Forty adult male Wistar rats (250–300 g) were divided into four groups: (1) sham, (2) neurorrhaphy: the sciatic nerve was sectioned and repaired using epineural sutures, (3) culture medium: after the suture, received an injection of 10 μL of culture medium into the nerve, and (4) mononuclear cell: after the suture, a concentration of 3 × 10⁶ of mononuclear cell was injected in epineurium region. Mononuclear cells were obtained from the bone marrow aspirates and separated by Ficoll‐Hypaque method. The histological analyses were performed at the 4th postoperative day. The sciatic functional index, histological, and morphometric analyzes were used to evaluate nerve regeneration at the 6th postoperative week. Six rats were used for immunohistochemical analysis on the 4th postoperative day. In the group 4, on the fourth day, the histological analysis demonstrated a more accelerated degenerative process and an increase of the neurotrophic factors was observed. In the 6th week, all the morphometric results of the group 4 were statistically better compared with groups 2 and 3. There was a statistically significant improvement in the sciatic functional index for group 4 compared with groups 2 and 3. Mononuclear cells stimulated nerve regeneration, most probably by speeding up the Wallerian degeneration process as well as stimulating the synthesis of neurotrophic factors. Microsc. Res. Tech., 2011. © 2010 Wiley‐Liss, Inc.     

A preliminary study of presence of resveratrol in skins and pulps of European and Japanese plum cultivars

BACKGROUND: Resveratrol is a polyphenol with health properties being mainly present in the skins of several foods. However, any study has been carried out to analyze the presence of this stilbene in the plum fruit from the genus Prunus in European and Japanese cultivars. RESULTS: The analysis of resveratrol from the skin in different cultivars of plums from Spanish markets with liquid chromatography coupled to ultraviolet (LC‐UV) detector with subsequent confirmation by LC‐MS/MS has been demonstrated that contents of this compound in plums ranged from 0.1 to 6.2 µg/g. CONCLUSIONS: Values of resveratrol in European plum cultivars is higher than in Japanese cultivars. Copyright © 2012 Society of Chemical Industry     

Enhancing the performance of TCP over Wi-Fi power saving mechanisms

The Wi-Fi technology is quickly being adopted by new types of devices that pose stringent requirements in terms of energy efficiency. In order to address these requirements the IEEE 802.11 group developed in the recent years several power saving protocols, that are today widely used among devices like smartphones. In this paper we study, by means of analysis and simulation, the effect that these power saving protocols have on the performance/energy trade-off experienced by long lived TCP traffic. Our study unveils that the efficiency of Wi-Fi power saving protocols critically depends on the bottleneck bandwidth experienced by a TCP connection. Based on the obtained insights, we design and evaluate a novel algorithm, BA-TA, which runs in a Wi-Fi station, does not require any modification to existing 802.11 standards, and using only information available at layer two, improves the performance/energy trade off of long lived TCP connections, whilst also exhibiting a notable performance with Web traffic and TCP Streaming.     

Changes in Structure, Rheology, and Water Mobility of Apple Tissue Induced by Osmotic Dehydration with Glucose or Trehalose

The impact of osmotic dehydration to water activity (a _w) at 0.97 or 0.94 with glucose or trehalose solutions on structure (optical and transmission electronic microscopy observations), rheological properties (small-scale dynamic oscillatory and creep/recovery measurements and large-scale compression force-deformation testing) and water mobility (¹H-NMR spectra) of parenchymatous apple tissue was investigated. In general, the nature and the concentration of sugar employed significantly affected the material properties and the structure of apple tissue. A dramatic loss in rigidity (E _d); an increase in deformation at rupture (?? _R ^R ), creep compliances (J ₀, J ₁, and J ₂), and fluidity (1/?? ₀) and a decrease in storage (G??) and loss (G??) moduli, true rupture stress (?? _R ^R ), and proton transverse relaxation times (T _2i) were induced by osmotic treatments. ?? _R ^R , C ₁, and T _2i parameters allowed to discriminate between the sugars used as osmotic agents while the different a _w levels for each sugar resulted in changes in ?? _R ^R , W, and T _2i values. Loss of turgor due to plasmolysis or rupture of membranes and desorganization/degradation of walls allowed explaining, at least partially, the changes in material parameters.     

Influence of Microstructure on The Resistance to Salt Crystallisation Damage in Brick

In the article we study the variation of brick durability and, more specifically, its resistance to salt crystallisation produced by changes in its microstructure during firing. For this purpose, the evolution of both mechanical and pore structure properties are studied within a wide range of temperatures (700–1100^∘C). An increase in the firing temperature produces a more homogeneous and resistant brick, measured using ultrasound velocity and uniaxial compressive strength. This result is obtained thanks to the vitrification process and changes in the brick's pore structure: larger, rounder pores, which are quantified by their roundness and fractal dimension. As a result of these changes, an excellent durability is achieved in the bricks studied when fired at temperatures above 1000^∘C. Considering that few differences are noted in pore structure and brick strength between 1000 and 1100^∘C, the recommended firing temperature is, for raw materials with a similar composition and production process, 1000^∘C, as this involves a lower production cost than firing at 1100^∘C.     

Characteristics and sensory assessment of extra virgin olive oils produced in two different zones of Brazil

The Brazilian olive oil production has been growing in recent decades and largest plantations are on two different zones, from Serra da Mantiqueira (states of Minas Gerais and São Paulo) and Campanha Gaúcha (state of Rio Grande do Sul). The total planted area, in 2022, reached approximately 6500 hectares. The aim of the present study was to characterize the sensory and analytical parameters of extra virgin olive oils (EVOO) from Southwestern (Serra da Mantiqueira) and Southern (Campanha Gaúcha) Brazil regions. Twenty-two EVOO samples were obtained from different cultivars of unlike regions. Quality parameters, oxidative stability, phenolic compounds ortho-diphenols and fatty acids were analyzed and relationships with olive variety or region. From the chemical perspective, the EVOO exhibited all parameters within the necessary to be qualified as extra virgin, according to international standard definitions. All samples showed a good quality of sensory perceptions and a high level of polyphenols, which are varied among samples but was more intense in Campanha Gaúcha olive oils.