Uma abordagem neural para estimação de conjugado em motores de indução

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Caracterização de leite bovino utilizando ultra-som e redes neurais artificiais

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Load torque estimation in induction motors using artificial neural networks

The induction motors are largely used in several industry sectors. The dimensioning of an induction motor has still been inaccurate because in most of the cases the load behavior in its shaft is completely unknown. The proposal of this paper is to use artificial neural networks as tool for dimensioning of induction motors rather than conventional methods, which use classical identification techniques and mechanical load modeling. Simulation results are also presented to validate the proposed approach.

Enamel caries resistance accidentally irradiated by the Nd : YAG laser

When the carious tissue is eliminated either by conventional methods (with burs) or with lasers, the risk of accidentally damage the surface of adjacent teeth may occur, which hypothetically could lead to a more susceptible surface for canes formation. This in vitro study aims to evaluate the caries resistance of the dental enamel surface irradiated by the Nd:YAG laser applied in conditions simulating accidental exposition. Thirteen third molars were used in this study. The experimental groups were: G1: sound control and control + carious; G2: contact Nd:YAG laser at 0.75, 1, 2, or 3 W; 10 Hz; 3 sec (27, 35, 71, and 106 J/cm(2)); G3: same parameters from G2 + caries artificial induction through the demineralization and demineralization (DES/RE) dynamic model. The caries resistance analysis was evaluated by the superficial morphological aspect through SEM images and also by Ca/P proportion through energy dispersive X-ray spectroscopy (EDX). The micrograph images showed that the Nd:YAG laser changed the normalmorphology of the enamel prisms resulting in a melted and re-solidified surface intensified with the power increase. Significant statistical differences were observed applying the Kruskal-Wallis statistical test (p <= 0.01) among the Nd:YAG laser irradiated groups and the control with caries regarding the Ca/P proportion. As an exception, this was not observed when 3 W; 10 Hz; 3 sec; 106 J/cm(2) was applied and posteriously submitted to a cariogenic challenge. The results indicate that the Nd:YAG laser accidental irradiation at low power settings did not represent risks to the enamel caries resistance.

High-efficient microwave synthesis and characterisation of SrSnO3

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Strategies for plane change of Earth orbits using lunar gravity and derived trajectories of family G

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Improving the field production environment for soybeans

During the past 10 years, soybeans have reached a prominent position among crops in the world. A substantial contribution to world production has been achieved by tropical countries, due to favorable conditions for high yields. Two limitations keep commercial yields below those obtained in experimental results (above 3,000 kg/ha): one is the lack of local adapted varieties and the other is an adequate field production environment. Solutions must be obtained by local research data. Seedbed preparation is one of the most important production steps, since the other production practices are dependent on it. Conventional methods and minimum tillage, when soybeans follow another crop, are being used, with the problem of soil compaction and losses by erosion. Looking for superior strains of Rhizobium is crucial because nitrogen can be supplied by a proper symbiosis. The addition of limestone to the soil is a common practice used to raise the pH to proper levels. The use of fertilizers should be guided by local research findings. Chemical control of weeds, pests and diseases is needed to prevent yield losses, but possible effects on the environment should be considered. © 1981 American Oil Chemists' Society.

Identificação de Enterobacter spp. através de técnicas convencionais e do sistema semi-automatizado Microscan (Autoscan-4)

A hundred and ninety-five (195) strains of Enterobacter spp., isolated from diverse clinical specimens - urine, feces, cateter, blood, wound, tracheal aspirate, vaginal fluid - were submitted to the conventional identification by biochemical tests, and were also submitted to the identification by panels NegCombo 20 of the system automated MicroScan - AutoScan- 4 (Dade Behring Inc., West Sacramento, CA, USA). The samples were from patients of the Clinical Laboratory from the School of Pharmacy and Biochemistry of UNOESTE, Presidente Prudente, SP, and from patients hospitalized at the University Hospital Domingos Leonardo Cerávolo, UNOESTE. Of the total of strains tested, 191 (97.9%) presented agreement between the two approaches utilized and 4 strains (2.1%) presented identification disagreement, that is, the genus identified was different in each approach. By this study, the conclusion is that both the approaches utilized for the identification presented advantages and disadvantages related to the cost, facility of execution, quickness, reliability and some other characteristics. Even so, our results showed that conventional methods represent a reliable tool for Enterobacter identification.

Determinação de fármacos diuréticos em associação por cromatografia em camada delgada e espectrofotometria

A rapid, sensitive and reliable thin-layer chromatography/spectrophotometry screening procedure was developed for quantitative determination of diuretics associated in pharmaceutical dosage forms. The chromatographic method employed microcrystalline cellulose and butanol : acetic acid : water (4:1:1) or amilic alcohol : ammonium hydroxide 25% (9:1) as mobile phases and detection by U.V. light. The drugs were extracted using a simple procedure and were quantified by U.V. spectrophotometry. Results varied from 97.5 to 102.5% and are similar to those obtained by conventional methods. This method of quantification of diuretics is promising for quality control of drugs.

A set of linear equations to calculate the steady-state operation of an electrical distribution system

In this paper, the calculation of the steady-state operation of a radial/meshed electrical distribution system (EDS) through solving a system of linear equations (non-iterative load flow) is presented. The constant power type demand of the EDS is modeled through linear approximations in terms of real and imaginary parts of the voltage taking into account the typical operating conditions of the EDS's. To illustrate the use of the proposed set of linear equations, a linear model for the optimal power flow with distributed generator is presented. Results using some test and real systems show the excellent performance of the proposed methodology when is compared with conventional methods. © 2011 IEEE.

Point vibration measurements for the detection of shallow-buried objects

A major UK initiative, entitled 'Mapping the Underworld', is seeking to address the serious social, environmental and economic consequences arising from an inability to locate accurately and comprehensively the buried utility service infrastructure without resorting to extensive excavations. Mapping the Underworld aims to develop and prove the efficacy of a multi-sensor device for accurate remote buried utility service detection, location and, where possible, identification. One of the technologies to be incorporated in the device is low-frequency vibro-acoustics, and application of this technique for detecting buried infrastructure is currently being investigated. Here, the potential for making a number of simple point vibration measurements in order to detect shallow-buried objects, in particular plastic pipes, is explored. Point measurements can be made relatively quickly without the need for arrays of surface sensors, which can be expensive, time-consuming to deploy, and sometimes impractical in congested areas. At low frequencies, the ground behaves as a simple single-degree-of-freedom (mass-spring) system with a well-defined resonance, the frequency of which will depend on the density and elastic properties of the soil locally. This resonance will be altered by the presence of a buried object whose properties differ from the surrounding soil. It is this behavior which can be exploited in order to detect the presence of a buried object, provided it is buried at a sufficiently shallow depth. The theoretical background is described and preliminary measurements are made both on a dedicated buried pipe rig and on the ground over a domestic waste pipe. Preliminary findings suggest that, for shallow-buried pipes, a measurement of this kind could be a quick and useful adjunct to more conventional methods of buried pipe detection. © 2012 Elsevier Ltd. All rights reserved.

A mixed-integer LP model for the reconfiguration of radial electric distribution systems considering distributed generation

The problem of reconfiguration of distribution systems considering the presence of distributed generation is modeled as a mixed-integer linear programming (MILP) problem in this paper. The demands of the electric distribution system are modeled through linear approximations in terms of real and imaginary parts of the voltage, taking into account typical operating conditions of the electric distribution system. The use of an MILP formulation has the following benefits: (a) a robust mathematical model that is equivalent to the mixed-integer non-linear programming model; (b) an efficient computational behavior with exiting MILP solvers; and (c) guarantees convergence to optimality using classical optimization techniques. Results from one test system and two real systems show the excellent performance of the proposed methodology compared with conventional methods. © 2012 Published by Elsevier B.V. All rights reserved.

Influência da combinação de dados GPS e GLONASS no georreferenciamento de imóveis rurais

The land question has been a widely discussed topic in Brazil, regarding land tenure. Law No. 10.267/01 was a major breakthrough for the agrarian issue. Since then on all rural properties must be georeferenced to the Brazilian Geodetic System (BGS). Therefore, satellite positioning and conventional methods are extensively used. Changes have been occurring in satellite positioning systems due to the addition of new signals in GPS (Global System Positioning), restructuring of GLONASS (Global Orbiting Navigation Satellite System), and the new systems like Galileo and Compass as well. To evaluate the effects of combining GPS and GLONASS data, several batches of processings were performed on different configurations. The data processing was performed to determine the coordinates of points of basic support and those materializing the neighborhood of the rural properties. As a result, it was found that the use of accurate ephemeris in transporting coordinates to support points has no significant influence, since transportation with broadcast ephemeris also meets the accuracy requirements for the Standard Technique for Georreferencing Rural Properties. On the other hand, when GPS and GLONASS data were used, such combination provides the best results. In the case of neighboring points, the use of GPS and GLONASS data is also recommended because such data meet the precision requirement and showed better results than those from where data were processed separately.

On the influence of the mode-shapes of a marine propulsion shafting system on the prediction of torsional stresses

Torsional vibration predictions and measurements of a marine propulsion system, which has both damping and a highly flexible coupling, are presented in this paper. Using the conventional approach to stress prediction in the shafting system, the numerical predictions and the experimental torsional vibration stress curves in some parts of the shafting system are found to be quite different. The free torsional vibration characteristics and forced torsional vibration response of the system are analyzed in detail to investigate this phenomenon. It is found that the second to fourth natural modes of the shafting system have significant local deformation. This results in large torsional resonant responses in different sections of the system corresponding to different engine speeds. The results show that when there is significant local deformation in the shafting system for different modes, then multi-point measurements should be made, rather than the conventional method of using a single measurement at the free end of the shaft, to obtain the full torsional vibration characteristics of the shafting system.

A novel straightforward compromising method for dynamic economic and emission dispatch considering valve-point effect

This paper proposes a straightforward compromising method to determine the output power of all committed units during the scheduling time horizon. Unlike the conventional methods that work based on a constant pollution control cost (CPCC), this method works based on the system topology such as demand, minimum cost and minimum output emission of the system. In order to have a meaningful compromise between costs and emission in economic and emission dispatch (EED) problem, a flexible pollution control cost (FPCC) is proposed. Also a dynamic economic emission dispatch (DEED) approach is considered where the ramping constraints couple the scheduling hours; the inclusion of valve-point effect makes the DEED modeling more practical. The validity and effectiveness of the unproblematic FPCC approach is verified through an IEEE 30-bus test system with 6 unit for the 6-hour scheduling horizon. © 2013 IEEE.