Instituto Federal do Piaui

Teresina, Brazil

Instituto Federal do Piaui

Teresina, Brazil
SEARCH FILTERS
Time filter
Source Type

Salgado M.D.F.,State University of Maranhão | Rodrigues S.C.S.,Instituto Federal do Piaui | Santos D.M.,Instituto Federal do Piaui | Brandim A.S.,Instituto Federal do Piaui | Lins V.F.C.,Federal University of Minas Gerais
Engineering Failure Analysis | Year: 2017

This work investigates the cyclic oxidation resistance of AISI 439 and AISI 441 ferritic stainless steels (FSS) at a typical temperature of muffler (300 °C). This temperature is characteristic of the cold exhaust of an automobile. The oxidation testing of steels was performed in synthetic air in a tube furnace under two different conditions: after immersing in the synthetic condensed (TOC) for 10 h and without immersion in the synthetic condensed (TOP). The mass gain of AISI 439 steel without previous immersion in condensate was the half of the mass gain of AISI 439 steel oxidized after immersion in condensate. In all samples, the Fe2O3 was only identified in the oxide layer on samples that oxidized after immersion in a condensate solution. The corrosion perforation of mufflers is mostly attributed to the cyclic and synergetic effect of oxidation and condensation processes of hot moisture-bearing exhaust gas. © 2017


Lima R.P.A.,Federal University of Alagoas | Lima F.N.,Instituto Federal do Piaui | Lyra M.L.,Federal University of Alagoas
Annals of Physics | Year: 2017

Within a first-order time-dependent perturbation approach, we compute the spontaneous decay rate of a two-level system placed in the vicinity of a perfectly reflecting spherical surface. We consider a model system on which the emitter is represented by a two-level monopole coupled to a Hermitian massless scalar field. Using the method of images, we determine the appropriate Green's function evaluated in the world line of the atom. The change in the spontaneous decay rate results from the interaction of the atom with its image. We provide a detailed analysis of the dependence of the decay rate on the sphere's radius, the atom's location, and the emitted radiation frequency. Both exterior and interior problems are discussed. © 2017 Elsevier Inc.


Anchieta R.T.,Instituto Federal do Piaui | Neto F.A.R.,Federal University of Pernambuco | De Sousa R.F.,Federal University of Piauí | Moura R.S.,Federal University of Piauí
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

This paper is a comparative study about text feature extractionmethods in statistical learning of sentiment classification. Featureextraction is one of the most important steps in classification systems.We use stylometry to compare with TF-IDF and Delta TF-IDF baselinemethods in sentiment classification. Stylometry is a research areaof Linguistics that uses statistical techniques to analyze literary style.In order to assess the viability of the stylometry, we create a corpus ofproduct reviews from the most traditional online service in Portuguese,namely, Buscapé. We gathered 2000 review about Smartphones. We usethree classifiers, Support Vector Machine (SVM), Naive Bayes, and J48to evaluate whether the stylometry has higher accuracy than the TFIDFand Delta TF-IDF methods in sentiment classification. We foundthe better result with the SVM classifier (82,75%) of accuracy with stylometryand (72,62%) with Delta TF-IDF and (56,25%) with TF-IDF.The results show that stylometry is quite feasible method for sentimentclassification, outperforming the accuracy of the baseline methods.We may emphasize that approach used has promising results. © Springer International Publishing Switzerland 2015.


Leite L.F.C.,EMBRAPA - Empresa Brasileira de Pesquisa Agropecuária | Iwata B.F.,Instituto Federal do Piaui | Araujo A.S.F.,Federal University of Piauí
Revista Arvore | Year: 2014

This study aimed at quantifying total organic carbon stocks and its pools in Acrisol under agroforestry systems with six (AFS6) and thirteen years old (AFS13), slash-and-burn agriculture (SBA) and savanna native forest (SNF) in northeastern Brazil. Soil samples were collected at 0-0.05 m, 0.05-0.10 m, 0.10-0.20 m and 0.20-0.40 m depths in the dry and rainy seasons to evaluate total organic carbon (TOC) stocks and labile carbon (LC), fulvic acid fraction (C-FAF), humic acid fraction (C-HAF), humin (C-HF) and microbial biomass carbon (Cmic) contents. Additionally, carbon management index (CMI) was determined. Higher TOC stocks (97.7 and 81.8 Mg ha-1 for the 0-0.40 m depth in the dry and rainy seasons, respectively) and LC, humic substances and Cmic contents were observed in the AFS13 in all the depths. CMI also was higher in the AFS13 (0-0. 05 m: 158 and 86; 0.05-0.10 m: 171 and 67, respectively for the dry and rainy seasons) especially when compared to the SBA (0-0.05 m: 5.6 and 5.4; 0.05-0.10 m: 5.3 and 5.8, respectively for dry and rainy seasons). The agroforestry systems increased soil quality through the conservation of organic matter and can be considered an excellent strategy to assurance sustainability in tropical soil of Northeastern Brazil. © 2014, Sociedade de Investigacoes Florestais. All rights reserved.


Silva A.P.,Federal University of Piauí | Silva M.P.,Nucleo de Pesquisa em Doencas Negligenciadas | Oliveira C.G.,Nucleo de Pesquisa em Doencas Negligenciadas | Monteiro D.C.,Nucleo de Pesquisa em Doencas Negligenciadas | And 5 more authors.
Toxicology in Vitro | Year: 2015

Garcinielliptone FC (GFC) is a natural prenylated benzophenone found in the seeds of Platonia insignis Mart. (Clusiaceae), a native Brazilian plant. It has been chemically characterized and it is known that GFC has several biological activities such as antioxidant and vasorelaxant properties. In this study, we report the in vitro effect of GFC against the blood fluke Schistosoma mansoni, the parasite responsible for schistosomiasis mansoni. The anti-. S. mansoni activity and cytotoxicity toward mammalian cells were determined for the compound. GFC. ≥. 6.25. μM showed antischistosomal activity and confocal laser scanning microscopy analysis demonstrated several morphological alterations on the tegument of worms, and a correlation between viability and tegumental damage was observed. In addition, at sub-lethal concentrations of GFC (≤3.125. μM), the number of S. mansoni eggs was reduced. More importantly, GFC exhibited no activity toward mammalian cells and, therefore, there is an appreciable selectivity of this compound against the helminths. In conclusion, these findings indicate the potential of GFC as an antiparasitic agent. © 2014 Elsevier Ltd.


Camelo J.H.,Federal University of Piauí | Rabelo R.L.,Federal University of Piauí | Passos E.,Instituto Federal do Piaui
Brazilian Symposium on Games and Digital Entertainment, SBGAMES | Year: 2014

Role-Playing Games (RPG) are widely popular, and the idea of living in a parallel virtual world has attracted players for decades. Currently, as RPGs come in several flavors, such as tabletop RPG and eletronic media, one feature is paramount: character customization, in which the player has the ability to choose gameplay (and sometimes visual) character attributes. However, when a player decides his favorite values for gameplay attributes (such as strength or dexterity), the 3D character he sees has no correlation with these attributes. In this work, we propose a system that can automatically map from gameplay attributes to character aesthetics by using fuzzy system, which knowledge base is derived from players' knowledge. Besides detailing the technique, we present a complete user experiment that includes from rules definition to validation of results. © 2014 IEEE.


Santos M.L.,Instituto Federal Do Piaui | De Souza R.,University of Pernambuco | Da Silva M.D.C.L.,Faculdade Estacio FIR
2016 8th Euro American Conference on Telematics and Information Systems, EATIS 2016 | Year: 2016

In this short paper we present an overview of MEIO (My Environment is Outstanding), an m-learning tool for environmental education combining aspects of social networks and gamification. The conceptual design of MEIO aims to foster the objectives of environmental education according to Tbilisi Declaration, to wit, awareness, knowledge, attitudes, skills and participation, in urban communities. The main goal is to encourage people to engage in denouncing and even solving (by themselves) environmental issues. MEIO bears clear similarities with urban navigation tools such as Waze, but instead of guiding drivers, it allows users to point out abnormalities such as water pollution, fire, etc. which become visible in an online map. A voting mechanism of the best actions realized by users leads to virtual rewards, this is the gamification component of our tool. MEIO is being developed initially for Android devides, and tests will be performed in two large cities in Brazil, Recife and Teresina. © 2016 IEEE.


Denis Eulalio A.,Instituto Federal Do Piaui | De Souza R.,University of Pernambuco | Diniz J.R.,University of Pernambuco
2016 8th Euro American Conference on Telematics and Information Systems, EATIS 2016 | Year: 2016

This article is an overview of a conceptual solution for the integration of heterogeneous information systems. Generally, universities have difficulties in obtaining information in an integrated way their information systems, for example, Learning Management System (LMS) and Academic Management System, a large part of these systems works in an isolated and without perspective way for offer services in an integrated way. In this context, the proposed solution uses Service Oriented Architecture (SOA) through Web Services and Cloud Computing in order to implement a model of integration between Moodle Learning Management System and Academic Management System Q-Academic of Instituto Federal de Educação, Ciência e Tecnologia do Piauí - IFPI. And in this way it contributes for the better management between these systems in which it is increasing the quality of information provided for users and reducing the possibility of mistakes caused by manual handling process information. This work also contributes in some way to increase the quality in the teaching process, because it allows for teachers more autonomy in their administrative tasks and teachers can also dedicate more time to develop their main activities. And, besides, it provides for students better information about their academic information. © 2016 IEEE.


De Jesus Ferreira Da Silva C.,Instituto Federal Do Piaui | Dos Santos Silva E.M.,Instituto Federal Do Piaui | Franca S.V.A.,University of Pernambuco
2016 8th Euro American Conference on Telematics and Information Systems, EATIS 2016 | Year: 2016

The use of technology in schools and the use of virtual environments to provide access to high school, technical education, higher education and Continuing Education are presented as an innovative proposal within the possibilities for educators of our country. In this perspective is that there are tools that should be used by students who have any special needs, in which the school must have knowledge and special conditions of pedagogical resources for the development of academic activities, thus contributing to the education Accessibility. Therefore, this paper aims to analyze the learning objects available in the international repository of Learning Objects - (LOs) that treat the subject Homologous chromosomes and have accessibility criteria. In addition, it presents an example of Learning Object, created by the multidisciplinary team of the Learning Object Lab - LOA, of Instituto Federal de Educação, Ciência e Tecnologia do Piauí - IFPI, which provides education with affordability. The research is qualitative and the results show that the object of learning analyzed do not present any of the accessibility criteria. © 2016 IEEE.


Souza M.A.M.,Instituto Federal Do Piaui | Duarte J.R.R.,Instituto Federal Do Piaui
Physics Education | Year: 2015

In this paper, we propose some of the strategies and methodologies for teaching high-school physics topics through an educational robotics show. This exhibition was part of a set of actions promoted by a Brazilian government program of incentive for teaching activities, whose primary focus is the training of teachers, the improvement of teaching in public schools, the dissemination of science, and the formation of new scientists and researchers. By means of workshops, banners and the prototyping of robotics, we were able to create a connection between the study areas and their surroundings, making learning meaningful and accessible for the students involved and contributing to their cognitive development. © 2015 IOP Publishing Ltd.

Loading Instituto Federal do Piaui collaborators
Loading Instituto Federal do Piaui collaborators