Fabiano Silva

Catalisadores heterogêneos para a produção de monoésteres graxos (biodiesel)

The recent increase in the world biodiesel demand, along with the need to reduce costs while improving the environmental sustainability of the entire biodiesel production chain, have led to the search for heterogeneous catalysts that would be efficient and highly amenable to recycling. Many classes of materials have been tested for these purposes. Among these are zeolites, ion-exchange resins, inorganic oxides, guanidines, metal complexes, layered compounds and ionic liquids. This review article describes the structure, properties, synthesis and performance of compounds that are catalytic active in both esterification and transesterification reactions.

Kruskal's Algorithm for Query Tree Optimization

This paper describes an implementation of Kruskals algorithm in query optimization process for generation of a near optimal execution query tree. The open source Post- greSQL DBMS was used in the experiments since its query optimization is performed by dynamic programming and genetic algorithm, which allows a concrete comparison with our approach. Kruskals algorithm presents some advantages like its simplified code, its polynomial-time execution and the reduced search space to generate only one query tree, that will be the optimal tree. In most experiments, Kruskals algorithm got the expected results in almost the same time as the results achieved by default Post- greSQLs optimization algorithms. The results confirm that Kruskals algorithm is a feasible method for query optimization.

Petriplan: A New Algorithm for Plan Generation (Preliminary Report)

Recent research shows that Integer Programming techniques are a very promising tool in the AI Planning area. In this paper we define the planning problem as a submarking reachability problem in a Petri net, which is solved by the use of standard IP methods. Using a similar idea to that of the Blackbox algorithm, we show how to translate the plan graph obtained in the first phase of Graphplan into an acyclic Petri net.

On Modelling Virtual Machine Consolidation to Pseudo-Boolean Constraints

Cloud Computing is a new paradigm of distributed computing that offers virtualized resources and services over the Internet. To offer Infrastructure-as-a-Service (IaaS) many Cloud providers uses a large data center which usage ranges 5% to 10% of capacity in average. In order to improve Cloud data center management and resources usage a Virtual Machine (VM) consolidation technique can be applied to increase workloads and save energy. Using VM consolidation, we introduce an artificial intelligence consolidation based in Pseudo-Boolean (PB) Constraints to find a optimal consolidation. To evaluate our PB consolidation approach we used the DInf-UFPR and Google Cluster scenario and the formulas are solved with two state-of-the-art solvers.

LDHs Instability in Esterification Reactions and Their Conversion to Catalytically Active Layered Carboxylates

Layered double hydroxides (LDH) containing Zn/Al and Mg/Al with different counter-ions and M2+/M3+ ratios were synthesized and used as catalysts in the esterification of fatty acids with methanol. High conversion rates were obtained depending on the reaction conditions. However, LDHs were also converted in situ into layered carboxylates and this new material was responsible for the observed catalytic activity, which was preserved even after several consecutive reuse cycles.Graphical AbstractXRD patterns (A) and FTIR spectra (B) of synthetic LDHs.

Stableness in large join query optimization

In relational database model, the use of exhaustive search methods in the large join query optimization is prohibitive because of the exponential increase of search space. An alternative widely discussed is the use of randomized search techniques. Several previous researches have been showed that the use of randomized sampling in query optimization permits to find, in average, near optimal plans in polynomial time. However, due to their random components, the quality of yielded plans for the same query may vary a lot, making the response time of a submitted query unpredictable. On the other hand, the use of heuristic optimization may increase stability of response time. This characteristic is essential in environments where response time must be predicted. In this paper, we will compare a randomized algorithm and a heuristic algorithm applied to large join query optimization. We used an open source DBMS as experimental framework and we compared the quality and stability of these algorithms.

Metal glycerolates as catalysts in the transesterification of refined soybean oil with methanol under reflux conditions

Divalent metal glycerolates were synthesized and investigated in the methyl transesterification of refined soybean oil. Higher conversions to monoacylesters were obtained for strontium and barium monoglycerolates and calcium diglycerolate. Calcium diglycerolate was shown to be stable up to a third reuse cycle, decomposing to an inactive mixture of CaCO3 and Ca(OH)2.

Time Series Discretization Based on the Approximation of the Local Slope Information

In the last decade symbolic representations approaches have shown effectiveness for knowledge discovery in time series, such as the Symbolic Aggregate Approximation (SAX). However, SAX doesn’t preserve the local slope information of the time series because it uses only the mean values of the segments. The modification Extended SAX (ESAX) proposed to treat this problem by the dimensionality increase. In this paper, we present a symbolic representation method that preserves the behavior of local slope characteristics in the symbolic representations of the time series. The proposed method was evaluated with three different discretization approaches and compared with the SAX and the ESAX algorithms. The experimental evaluation, using artificial and real datasets with 1-nearest-neighbor classification, demonstrate the method effectiveness to reduce the error rates of time series classification and to keep the local slope information in the symbolic representations.

Alternância entre competição e colaboração para promover o aprendizado por meio de heurísticas de jogos

Resumo: Em busca de novos metodos que auxiliem no aprendizado de portadores de necessidades especiais, um jogo utilizando a tecnologia de agentes virtuais foi criado, atraves da linguagem brasileira de sinais, LIBRAS, o modelo grafico repassa toda informacao necessaria a manipulacao do jogo didatico, despertando no aluno a autonomia e o interesse pelo conteudo abordado. Abstract: Looking for new methods to help learning, a game using the technology of virtual agent was created, a graphic model using the LIBRAS language to transmit all information that is necessary to the student to manipulate the game, increasing his will of learning and self improving.Resumo: Tem sido ampla e intensamente divulgado e aplicado o uso do computador para fins de aprendizagem em diversos dominios. Partindo dessa perspectiva, deu-se inicio a um trabalho na Casa de Saude Paulo de Tarso, o qual tem como objetivo primordial auxiliar na melhoria da coordenacao motora dos pacientes da referida Instituicao e, por consequencia, aumentar a auto-estima, contribuir com o aprendizado, dentre outros. Abstract: The use of the computer has been wide and intensely divulged and applied in the learning process in diverse dominions. In agreement with this perspective, it was started a work at the Health Institution “Paulo de Tarso”, which has as its major goal to assistant in the improvement of the patients motor coordination in the above-mentioned Institution and, by consequence, to augment the self-esteem, to contribute to apprenticeship, among others.Resumo: A Universidade Federal de Mato Grosso (UFMT) - Campus de Rondonopolis, atraves de alguns estudantes, do 4o ano do curso de Licenciatura em Informatica, em pleno exercicio de seu estagio supervisionado, firmou uma parceria com a EEMOP (Escola Estadual Major Otavio Pitaluga) em maio de 2005 para que juntos realizassem um trabalho, onde os estagiarios estariam auxiliando a utilizacao da Internet durante o processo de ensino-aprendizagem na referida escola. Abstract: Mato Grosso’s Federal University (UFMT) Rondonopolis’s Campus, through some students, of the fourth year of the Graduation Course of Degreee in Informatics, in full exercise of their supervised probation period, established a partnership with EEMOP (Major Otavio Pitaluga State School) in may of 2005 so that together they could accomplish a work, where the trainees would be assisting the use of Internet during the teaching- learning process at the above-mentioned school.Resumo: A educacao a distância (EAD) se apresenta no seculo XXI como um novo espaco de trabalho docente, trazendo mudancas nos papeis tradicionais, requerendo um preparo especial do professor. Para verificar se as IES que oferecem EAD formam seus docentes para ensinar a distância e como fazem este trabalho, foi feita uma pesquisa atraves de questionarios enviados por e- mail para 15 IES de Santa Catarina. O presente artigo discute os resultados encontrados que mostraram que as IES catarinenses nao apenas se preocupam com a producao de materiais didaticos, mas estao criando estruturas de apoio para formar seus professores para ensinar a distância. Abstract: Distance education (DE) is presenting, in the 21st century, a new challenge for teachers, asking for a change in their traditional roles, and requiring them to be specially trained for it. In order to find out if the Higher Education Institutions offering DE are training their teachers to work at a distance and how this preparation has been done, a research was conducted in the state of Santa Catarina, Brazil, using a questionnaire, sent by e-mail to 15 institutions. This article presents and discuss the results, showing that the Higher Education Institutions offering DE are not concerned only about the production of the course materials but are, also, creating support structures to prepare their professionals to teach at a distance.Resumo: Este artigo apresenta resultados iniciais de uma pesquisa visando diagnosticar a situacao da informatica educativa no municipio de Belem(PA). Esse diagnostico foi feito tendo-se como referencia um conjunto de criterios propostos para o planejamento e a avaliacao de experiencias em informatica educativa. Entre os resultados apresentados pode-se destacar o contraste entre a rede publica e a privada e o baixo investimento na formacao docente para essa atividade. Abstract: This paper presents the initial results of a diagnostic of the current state of educative informatics in Belem, Para. To perform such analysis, we used a set of criteria that aimed to evaluate the different educative informatics experiences reported. Among the results it is possible to notice clearly the contrast between the public and private school system and the low investment in the teaching personnel.

ESTERIFICAÇÃO E TRANSESTERIFICAÇÃO SIMULTÂNEAS DE ÓLEOS ÁCIDOS UTILIZANDO CARBOXILATOS LAMELARES DE ZINCO COMO CATALISADORES BIFUNCIONAIS

Palm oil containing 40% fatty acids was converted to methyl esters using zinc carboxylates as the esterification/transesterification catalyst. The reaction was optimized using a factorial design in which the effects of the alcohol:fatty acids molar ratio (MRAG) and the catalyst concentration (CAT) were assessed. The best conversion was achieved with CAT at 4 wt% and MRAG at 4:1. However, the solid catalyst presented significant structural changes after use. For instance, laurate anions were replaced by carboxylates of higher molecular mass, leading to the formation of a new catalytically active layered structure. Also, the glycerin obtained as a co-product contained 86 wt% glycerol.