167 resultados para PES


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The present literature review aimed to describe biodisel’s physicochemical properties obtained from different raw materials. Were studied data concerning viscosity, density, cetane number, fl ash point, pour point and calorifi c power of biodiesel produced from soybean oil, coconut, rice bran, cotton, pequi, babassu, mamona, palm, castor, sunfl ower, corn, canola, jatropha and karanja. Considering the diversity of vegetal and animal sources that can be used on the biodiesel production, it is noteworthy the lack of data concerning physicochemical properties of unexplored raw materials. This work may contribute for the creation of database about physicochemical properties of oil and biodiesel from different sources which will allow design and scale-up, both the necessary equipment to the production line and reciprocating engines.

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Indiscriminate and inappropriate use of pesticides in agriculture has been pointed out for increasing health problems and environmental damage. Considering that water resources are the principal destiny of those compounds after application, the present study presents optimization and validation of two simple and effi cient analytical methods for pesticides quantifi cation in both surface and groundwater. Were selected the pesticides more commonly used at Dourados (MS - Brazil), region with intense agricultural activity. Pesticides were preconcentrated by solid-phase extraction using C18 (500 mg) cartridges and then divided in two groups for elution and quantifi cation: 2.4-D and 2.4-DCP were eluted with methanol and quantifi ed by high performance liquid chromatography with ultra-violet detector (HPLC-UV) while atrazine, DIA, DEA, trifl uralin and methyl parathion were eluted with ethylacetate (1:1, v/v) and quantifi ed by gas chromatography with thermionic specifi c detector (GC-TSD). The methods showed satisfactory accuracy (76-107%) and precision (<12%) for the substances analyzed at the fortifi ed levels selected for the study, except for DIA (<51%). Study of pesticide stability also presented good results: C18 cartridges could be stored for at least for 21 days at -20ºC with no signs of the compounds degradability. Both methods limits of quantifi cation of the pesticides (0.22 - 0.48 μg L-1) are in accordance to the levels currently established by the Brazilian national legislation for pesticides in water. Although only the pesticide 2.4-D has been detected in two distinct collection points in the study period of time, this work warns for the requirement of systematical analysis of pesticides presence in water destined to human consume, principally in areas of intense agriculture activity. Such monitoring can provide subsidies for public environmental policies.

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Finney claims that we did not include transaction costs while assessing the economic costs of a set-aside program in Brazil and that accounting for them could potentially render large payments for environmental services (PES) projects unfeasible. We agree with the need for a better understanding of transaction costs but provide evidence that they do not alter the feasibility of the set-aside scheme we proposed.

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A new mixed-integer linear programming (MILP) model is proposed to represent the plug-in electric vehicles (PEVs) charging coordination problem in electrical distribution systems. The proposed model defines the optimal charging schedule for each division of the considered period of time that minimizes the total energy costs. Moreover, priority charging criteria is taken into account. The steady-state operation of the electrical distribution system, as well as the PEV batteries charging is mathematically represented; furthermore, constraints related to limits of voltage, current and power generation are included. The proposed mathematical model was applied in an electrical distribution system used in the specialized literature and the results show that the model can be used in the solution of the PEVs charging problem.

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This paper presents a mixed-integer convex-optimization-based approach for optimum investment reactive power sources in transmission systems. Unlike some convex-optimization techniques for the reactive power planning solution, in the proposed approach the taps settings of under-load tap-changing of transformers are modeled as a mixed-integer linear set equations. Are also considered the continuous and discrete variables for the existing and new capacitive and reactive power sources. The problem is solved for three significant demand scenarios (low demand, average demand and peak demand). Numerical results are presented for the CIGRE-32 electric power system.

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In a smart grid environment, attention should be paid not only to the power supplied to satisfy loads and system losses but also to the services necessary to provide security and stability to the system: the so-called ancillary services. As they are well known the benefits that distributed generation can bring to electrical systems and to the environment, in this work the possibility that active power reserve for frequency control could be provided by distributed generators (DGs) in an efficient and economical way is explored. The proposed methodology was tested using the IEEE 34-bus distribution test system. The results show improvements in the capacity of the system for this ancillary service and decrease in system losses and payments of the distribution system operator to the DGs.

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The Meiglyptini comprise eight species grouped into three genera: Meiglyptes and Mulleripicus, with three species each, and Hemicircus, with two species. The aim of the present study was to describe the cranial osteology of six species and three genera of Meiglyptini and to compare them to each other, as well as with other species of woodpeckers and other bird groups. The cranial osteology varied among the investigated species, but the most markedly distinct characteristics were: (1) a frontal overhang is only observed in the middle portion of the frontale of H. concretus; (2) the Proc. zygomaticus and suprameaticus are thick and long in species of the genus Mulleripicus, but short in other species; (3) the Pes pterygoidei is relatively larger in species of the genus Mulleripicus, while it is narrow, thin and relatively smaller in species of the genus Meiglyptes and indistinct in H. concretus; (4) the bony projection of the ectethmoidale is relatively short and thin in species of Mulleripicus and more developed in H. concretus. It appears that the greatest structural complexity of the cranial osteology is associated with the birds' diet, with the frugivorous H. concretus being markedly different from the insectivorous species.

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Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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This study aimed at investigating, in the national and international scientific literature, how aromatherapy is used as a therapeutic tool to reduce anxiety. It is a bibliographic study that adopted integrative literature review as a method. Studies published on databases Scielo, Medline and Cinahl from 2008 to 2012 were selected. A sample of 20 scientific articles was analyzed, and of these, 13 had an experimental and a quasi--experimental design whereas 07 were systematic or integrative reviews. The synthesis of knowledge sho-wed that aromatherapy represents a safe therapeutic practice although it is still underestimated in health care practices. The construction of evidence levels was not possible due to discrepancies in the studied populations, in research designs, the various essential oils used and the different methods for aromatherapy application. The knowledge gaps identified in these studies are related to the need to develop new forms to evaluate the effectiveness of this practice, including the therapist-patient relationship and the different communication forms that are intrinsic to aromatherapy.