A integração do tutorial interativo TryLogic via IMS Learning Tools Interoperability: construindo uma infraestrutura para o ensino de Lógica através de estratégias de demonstração e refutação

Logic courses represent a pedagogical challenge and the recorded number of cases of failures and of discontinuity in them is often high. Amont other difficulties, students face a cognitive overload to understand logical concepts in a relevant way. On that track, computational tools for learning are resources that help both in alleviating the cognitive overload scenarios and in allowing for the practical experimenting with theoretical concepts. The present study proposes an interactive tutorial, namely the TryLogic, aimed at teaching to solve logical conjectures either by proofs or refutations. The tool was developed from the architecture of the tool TryOcaml, through support of the communication of the web interface ProofWeb in accessing the proof assistant Coq. The goals of TryLogic are: (1) presenting a set of lessons for applying heuristic strategies in solving problems set in Propositional Logic; (2) stepwise organizing the exposition of concepts related to Natural Deduction and to Propositional Semantics in sequential steps; (3) providing interactive tasks to the students. The present study also aims at: presenting our implementation of a formal system for refutation; describing the integration of our infrastructure with the Virtual Learning Environment Moodle through the IMS Learning Tools Interoperability specification; presenting the Conjecture Generator that works for the tasks involving proving and refuting; and, finally to evaluate the learning experience of Logic students through the application of the conjecture solving task associated to the use of the TryLogic

Estudo da influência de compostos recalcitrantes na remoção de matéria orgânica biodegradável no tratamento de efluente de refinarias de petróleo

Petroleum Refinery wastewaters (PRW) have hart-to-degrade compounds, such as: phenols, ammonia, cyanides, sulfides, oils and greases and the mono and polynuclear aromatic hydrocarbons: benzene, toluene and xylene (BTX), acenaphthene, nitrobenzene and naphtalene. It is known that the microrganisms activity can be reduced in the presence of certain substances, adversely affecting the biological process of wastewater treatment. This research was instigated due the small number of studies regarding to this specific topic in the avaiable literature. This body of work ims to evaluate the effect of toxic substances on the biodegradability of the organic material found in PRW. Glucose was chosen as the model substrate due to its biodegradable nature. This study was divided into three parts: i) a survey of recalcitants compounds and the removal of phenol by using both biological and photochemical-biological processes; ii) biomass aclimation and iii) evaluation of the inhibitory effect certain compounds have on glucose biodegradation. The phenol degradation experiments were carried out in an activity sludge system and in a photochemical reactor. The results showed the photochemical-biological process to be more effective on phenol degradation, suggesting the superioruty of a combined photochemical-biological treatment when compared with a simple biological process for phenol removal from industry wastewaters. For the acclimation step, was used an activated sludge from industrial wastewaters. A rapid biomass aclimation to a synthetic solution composed of the main inhibitory compouns fpund in a PRW was obtained using the following operation condition: (pH = 7,0; DO ≥ 2,0 mg/L; RS = 20 days e qH = 31,2 and 20,4 hours), The last part was consisted of using respirometry evaluation toxicity effects of selected compounds over oxygen uptake rate to adaptated and non adaptated biomass in the presence of inhibitory compounds. The adaptated sludge showed greater degration capacity, with lower sensibility to toxic effects. The respirometry has proved to be very practical, as the techiniques used were simple and rapid, such as: Chemical Oxygen Demand (COD), Dissolved Oxygen (DO), and Volatile Suspended Solids (VSS). Using the latter it is possible to perform sludge selection to beggingthe process; thus allowing its use for aerobic treatment system`s behacior prediction

Estudo das propriedades magnéticas e estruturais do composto (Sm1 - xMMx)2Fe17 e seus nitretos

Conselho Nacional de Desenvolvimento Científico e Tecnológico

"Ombro a ombro com os mais fracos": a inserção de João Café Filho nos espaços do trabalhador na cidade do Natal 1922 - 1937

The purpose of this thesis is to analyze how João Café Filho constituted a discourse of advocate of the labor movement and workers in different sociability spaces. It is intended to understand, on one hand, how political relations were established between different categories of workers and the ‘middle classes’ and, on the other hand, how places were instituted to house the meeting of these relations. It a ims to understand the insertion of Café Filho in union activities in the urban world. It demonstrates specificities of the political culture in Natal emphasizing the dispute between a city politically ruled by a still reigning rural paternalistic mentality and the rise of a new way to experience the urban conflicts which appeared. Temporally, the work is delimited between 1922 (proclaimed by Café Filho himself as the initial period of his political action) and 1937 (when he broke up with Vargas and went into exile in Argentina). The research was constituted by three main document types: several published newspapers between the decades of 1920 and 1930 in the cities of Natal, Recife, São Paulo, Porto Alegre and Rio de Janeiro; the autobiographical memoirs written by Café Filho himself and memoirs of other people who lived in his time. The main pillars that have supported the work were: the concepts of society and individuals (ELIAS, 1994; 1995), political cultures (BERSTEIN, 1998) and theater of the memory (GOMES, 2004); the sociability spaces category (CERTEAU, 1994; MALATIAN, 2001; RIOX, 1996); the biography notion (DOSSE, 2009; LORIGA, 2011). We demonstrated that Café Filho acted in some sociability spaces as: the Jornal do Norte, the Federação Regional do Trabalho and the Partido Democrático Nacional. In such spaces, Café Filho, gradually, become an important leader of workers and, at the same time, linked to national entities led to the opposition that fight against the power established in the Brazilian First Republic. In Café Filho’s interpretation, workers were individuals who needed to fight against the political structures prevailing at that time because the poor living conditions and the low representativeness of this group were caused by the way the political system in the First Republic was structured. After the 1930 Movement, the 3 de Outubro Club, the Jornal and the Labor Federation of Natal were constituted in spaces where the cafeista critical discourse about the government was changed: workers should follow the official syndicalism and defend the 1930 Movement which put Vargas in the presidency of the Republic.