Sampaio P.G.V.,Federal Rural University of the Semiarid Region |
Gonzalez M.O.A.,Federal University of Rio Grande do Norte
Renewable and Sustainable Energy Reviews | Year: 2017
The purpose of this article is to understand the state of art of photovoltaic solar energy through a systematic literature research, in which the following themes are approached: ways of obtaining the energy, its advantages and disadvantages, applications, current market, costs and technologies according to what has been approached in the scientific researches published until 2016. For this research, we performed a qualitative and quantitative approach with a non-probabilistic sample size, obtaining 142 articles published since 1996–2016 with a slitting cut. The analysis result of this research shows that studies about photovoltaic energy are rising and may perform an important role in reaching a high-energy demand around the world. To increase the participation of photovoltaic energy in the renewable energy market requires, first, to raise awareness regarding its benefits; to increase the research and development of new technologies; to implement public policies a programs that will encourage photovoltaic energy generation. Although crystal silicon solar cells were predominant, other types of cells have been developed, which can compete, both in terms of cost reduction of production, or in terms of greater efficiency. The main applications are dominated by telecommunications, water pumping, public lighting, BIPV, agriculture, water heating, grain drying, water desalination, space vehicles and satellites. The studies found on photovoltaic solar energy are all technical, thus creating the need for future research related to the economic viability, chain supply coordination, analysis of barriers and incentives to photovoltaic solar energy and deeper studies about the factors that influence the position of such technologies in the market. © 2017 Elsevier Ltd
Bukhsh F.A.,University of Twente |
Silva P.D.A.,Federal Rural University of the Semiarid Region
Proceedings - 14th International Conference on Frontiers of Information Technology, FIT 2016 | Year: 2017
E-commerce ideas demand validation regarding their economic effectiveness on businesses. For identifying relevant business values, some value modeling techniques are currently available in the research arena, and the e3value framework is an easy-to-use option. This framework has a notation to express different values in e-business scenarios. For most of customers, customization of requirements is usually necessary for standard products and services. In this paper, we discuss the need of e-Business customization, and design it using the e3value framework. We present then an approach of e-Business customization, followed by case-based evaluation. © 2016 IEEE.
De Oliveira Caju O.,Federal Rural University of the Semiarid Region
Revista de Direito, Estado e Telecomunicacoes | Year: 2017
Purpose -This article analyzes the votes uttered by the Federal Supreme Court justices at the trial of ADPF 130/DF, in which it was denied value to the Press Law. It also tackles the reasoning behind the Court's decision, which clarifies its conception of regulation of the social media. Methodology/approach/design -The first section of the article presents the most influent theoretical paradigms on the social media regulation. The second section confronts them with votes presented at the trial of the ADPF 130/DF and extract the guiding conceptual syntheses of the justices, identifying the regulatory paradigm of communicational field to which they align themselves. Findings - It was possible to identify that the libertarian paradigm of free flow of informartion is the predominant mindset guiding the rulings concerning social media in the Federal Supreme Court.
Goncalves A.A.,Federal Rural University of the Semiarid Region |
Gagnon G.A.,Dalhousie University
Ozone: Science and Engineering | Year: 2011
In recirculating aquaculture systems (RAS), particulates (including feces, uneaten feed, bacteria, and algae) can cause several problems, in that they may harbor pathogens, can physically irritate the fish, and upon decomposition, release ammonia and consume oxygen. Mechanical filters, foam fractionators, and other engineered devices are used to remove particles quickly from aquaculture systems, in order to improve fish health and decrease the load on biofilters and oxygenators. Ozone is used in RAS as a disinfectant, to remove organic carbon, and also to remove turbidity, algae, color, odor and taste. Ozone can effectively inactivate a range of bacterial, viral, fungal and protozoan fish pathogens. But the effectiveness of ozone treatment depends on ozone concentration, length of ozone exposure (contact time), pathogen loads and levels of organic matter. In spite of ozone is a very effective oxidizing agent, higher ozone concentrations are a risk to cultured fish stocks causing gross tissue damage and stock mortalities, and also are a risk to bacterial films on the biofilter. © 2011 International Ozone Association.
Guimaraes D.V.,Federal University of Sergipe |
Gonzaga M.I.S.,Federal University of Sergipe |
da Silva T.O.,Federal University of Sergipe |
da Silva T.L.,Federal University of Sergipe |
And 2 more authors.
Soil and Tillage Research | Year: 2012
Changes in tropical land use have profound effects on soil organic matter (SOM) status. It has been suggested that alterations in the different fractions of SOM are more effective in indicating changes in soil use than total soil organic matter content. The main objective of this study was to investigate changes in the content of humic substances in an Ultisol under different land uses, in the northeast region of Brazil. Soil samples were collected from the 0-10 and 10-30. cm layers, in three agricultural areas (conventional coconut orchard, integrated coconut orchard, and citrus orchard). A native forest soil was used as reference. Organic C and total N were determined to characterize the SOM. Humic substances were chemically fractionated into fulvic acid, humic acid, and humin, based on solubility in acid and alkali. Significant loss (47.5%) of soil organic matter was observed in the surface layers of the conventional coconut and citrus orchards, compared to the native forest. There was increased SOM content in the integrated coconut orchard soil, due to the presence of cover crops as well as management of crop residues. However, in the subsurface soil of the integrated coconut orchard, cultivation modified the distribution of the more labile fractions of the soil organic matter, as measured by the ratio between humic and fulvic acids (>1.0), indicating a substantial loss of fulvic acids. The degree of humification was in the range 40-97%. The distributions of the soil organic matter fractions varied in the ranges 12-32.5% (fulvic acids), 12-34.5% (humic acids), and 40-69.5% (humin). © 2012 Elsevier B.V.
Maia C.E.,Federal Rural University of the Semiarid Region
Ciencia Rural | Year: 2010
The information of wetting soil volume under drip irrigation has great importance in design and management of surface drip irrigation for delivering required amount of water to the plant. This study aimed to describe the wetted soil volume for five mathematic models by water applied on soil surface from drip emitter. For that, six experiments were installed in different soils (Entisol, Ultisol, Inceptisol, Psamment, Oxisol, Fluvent) with the objective of evaluating models which can estimate wetted soil volume in function of emitter discharged and time of water application. It was concluded that except for the model proposed by NARDA & CHAWLA, the other models estimated satisfactorily the wetted soil volume for the superficial drip irrigation. The wetted soil volume for the same combinations of emitter discharged and water application time, were larger for Ultisol and smaller for Fluvent and excepting Ultisol and Fluvent, the wetted soil volume can be estimated for a single equation in function of emitter discharged and time of water application.
Baldauf C.,University of Campinas |
Baldauf C.,Federal Rural University of the Semiarid Region |
Maes dos Santos F.,University of Campinas
Economic Botany | Year: 2013
Ethnobotany, Traditional Knowledge, and Diachronic Changes in Non-Timber Forest Products Management: A Case Study of Himatanthus drasticus (Apocynaceae) in the Brazilian Savanna. The analysis of factors and processes that affect the traditional knowledge and the management practices deriving from it are essential for devising conservation strategies for non-timber forest products. The purpose of this study is to assess the traditional knowledge and analyze diachronic changes in management systems for non-timber forest products in a case study of an intensely exploited species from the Brazilian savanna, Himatanthus drasticus, commonly known as "janaguba." Janaguba produces a latex of commercial value, widely used in popular medicine in Brazil. Recent pharmacological evidence of its medicinal properties has increased harvesting pressure on this resource. For this reason, we carried out an ethnobotanical characterization of the management systems used to harvest janaguba latex and of the traditional ecological knowledge associated with such practices. Three management systems were identified in latex harvesting, which may have varying ecological impacts on janaguba populations, depending on the amount of bark removed and the time interval between harvestings. Among the factors that can influence changes in the management systems over time are market pressure and growing demand for the product, loss of traditional knowledge, the system of land tenure, and the biological characteristics of the species, especially its high biomass regeneration capacity. © 2013 The New York Botanical Garden.
Maia C.E.,Federal Rural University of the Semiarid Region
Ciencia Rural | Year: 2013
Soil is an important component of terrestrial ecosystems because it preserves nutrient reserves, supports many biological. To preserve this resource and its functions, it is necessary first of all to know the conditions and the processes occurring in it, for example, through the determination of soil quality. The aim of this study was to evaluate the environmental quality in Oxisol cultivated with different growing season of muskmelon. Were collected soil samples from nine areas with different growing season and compared with the native forest. It was concluded that environmental quality decreased with crop cycles when compared with the reference area of native forest.
Pommer C.V.,Federal Rural University of the Semiarid Region
Acta Horticulturae | Year: 2012
Guava is one of the most important fruits in a large number of countries of the world. In most countries where guava is important, genetic studies and breeding is done in different degrees and ways. Germplasm conservation and studies are practiced in places such as Colombia, Venezuela, USA, Malaysia and Nigeria. In these and other cases, objectives are to collect, introduce, characterize and select guava genotypes with defined and appropriate characteristics to production. Artificial pollination is mostly used. Conversely, countries such as Israel, Thailand, Cuba, Mexico, Brazil, Pakistan and India, especially the latter one, present active and productive guava breeding programs. On the other hand, this fact resulted in a very high variability in seedling populations from which promising genotypes have been selected, such as 'Paluma', the main Brazilian cultivar and many others, like 'Kumagai', 'Pedro Sato', 'Cortibel'. In India there are more than 150 cultivars, but only a few with commercial importance such as 'Allahabad Safeda', 'L-49' ('Sardar'), 'Hisar Surkha', 'Lucknow Safeda', 'Arka Amulya', which have been identified for commercial planting particularly in northern India, the main guava growing region. However, in the last 10-15 years crop improvement work carried out resulted in release of several superior selections and or hybrids, such as 'Safed Jam', 'Kohir Safeda' and 'Arka Amulya' in India, 'Século XXI' in Brazil, and others. Breeding programs also use techniques such as interspecific crosses and induced mutation, contributing to bring variability in different senses and characteristics. Molecular techniques and other new biotechnological tools are very helpful to study the extent of genetic variation among cultivars as well as to find out genetic markers for wilt resistance to improve efficiency in developing wilt resistant clones and rootstocks. Development studies still have to be done in aneuploidy breeding, development of autotetraploids and in vitro genetic manipulation of somatic cells. © ISHS.
Da Silva J.P.,Federal Rural University of the Semiarid Region
Microwave and Optical Technology Letters | Year: 2013
A new design of a microstructured optical fiber using cylindrical perfectly matched layers is proposed and analyzed through the vectorial beam propagation method (VBPM) in conjunction with genetic algorithm (GA). The fiber is made up from silica doped with germanium and it contains two and three identical horizontals cores surrounded by air holes. First, the signal power launched in the left core is completely transferred to the neighbor core with 100% of the coupling ratio. Next, the signal power launched in the central core is equally divided between the two neighboring cores with 50% of the coupling ratio. Through numerical simulations, it is demonstrated that the optical power can be completely transferred for a propagation distance around 6000 μm to the first application and 4000 μm to the second application. The behavior of the resulting geometry has been optimized by a genetic algorithm in conjunction with an efficient vectorial finite element formulation (GE-VBPM). © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:281-285, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27308 Copyright © 2012 Wiley Periodicals, Inc.