Thermochemical equilibrium modeling of a biomass downdraft gasifier: Constrained and unconstrained non-stoichiometric models

The objective of this work is to develop a non-stoichiometric equilibrium model to study parameter effects in the gasification process of a feedstock in downdraft gasifiers. The non-stoichiometric equilibrium model is also known as the Gibbs free energy minimization method. Four models were developed and tested. First a pure non-stoichiometric equilibrium model called M1 was developed; then the methane content was constrained by correlating experimental data and generating the model M2. A kinetic constraint that determines the apparent gasification rate was considered for model M3 and finally the two aforementioned constraints were implemented together in model M4. Models M2 and M4 showed to be the more accurate among the four developed models with mean RMS (root mean square error) values of 1.25 each.Also the gasification of Brazilian Pinus elliottii in a downdraft gasifier with air as gasification agent was studied. The input parameters considered were: (a) equivalence ratio (0.28-035); (b) moisture content (5-20%); (c) gasification time (30-120 min) and carbon conversion efficiency (80-100%). (C) 2014 Elsevier Ltd. All rights reserved.

Thermochemical equilibrium modeling of biomass downdraft gasifier: Stoichiometric models

The aim of this work is to develop stoichiometric equilibrium models that permit the study of parameters effect in the gasification process of a particular feedstock. In total four models were tested in order to determine the syngas composition. One of these four models, called M2, was based on the theoretical equilibrium constants modified by two correction factors determined using published experimental data. The other two models, M3 and M4 were based in correlations, while model M4 was based in correlations to determine the equilibrium constants, model M3 was based in correlations that relate the H-2, CO and CO2 content on the synthesis gas. Model M2 proved to be the more accurate and versatile among these four models, and also showed better results than some previously published models. Also a case study for the gasification of a blend of hardwood chips and glycerol at 80% and 20% respectively, was performed considering equivalence ratios form 0.3 to 0.5, moisture contents from 0%-20% and oxygen percentages in the gasification agent of 100%, 60% and 21%. (C) 2013 Elsevier Ltd. All rights reserved.

Correspondence between the one-loop three-point vertex and the Y and Delta electric resistor networks

Different mathematical methods have been applied to obtain the analytic result for the massless triangle Feynman diagram yielding a sum of four linearly independent (LI) hypergeometric functions of two variables F-4. This result is not physically acceptable when it is embedded in higher loops, because all four hypergeometric functions in the triangle result have the same region of convergence and further integration means going outside those regions of convergence. We could go outside those regions by using the well-known analytic continuation formulas obeyed by the F-4, but there are at least two ways we can do this. Which is the correct one? Whichever continuation one uses, it reduces a number of F-4 from four to three. This reduction in the number of hypergeometric functions can be understood by taking into account the fundamental physical constraint imposed by the conservation of momenta flowing along the three legs of the diagram. With this, the number of overall LI functions that enter the most general solution must reduce accordingly. It remains to determine which set of three LI solutions needs to be taken. To determine the exact structure and content of the analytic solution for the three-point function that can be embedded in higher loops, we use the analogy that exists between Feynman diagrams and electric circuit networks, in which the electric current flowing in the network plays the role of the momentum flowing in the lines of a Feynman diagram. This analogy is employed to define exactly which three out of the four hypergeometric functions are relevant to the analytic solution for the Feynman diagram. The analogy is built based on the equivalence between electric resistance circuit networks of types Y and Delta in which flows a conserved current. The equivalence is established via the theorem of minimum energy dissipation within circuits having these structures.

Comparação entre valores de ensaios experimentais e calculados da resistência ao embutimento da madeira de Pinus taeda L.

To design connections between timber parts with metal dowels (nails or bolts), two phenomena must be considered: bending of the metal dowel and the embedment strength in the wood. The Brazilian Standard ABNT NBR 7190:1997 proposes the methods used in the laboratory tests to determine the embedment strength with the metal dowell and, in the absence of testing, specifies relations to calculate the embedment strength from the compression strength. The aim of this research was to compare the embedment strength values obtained by experimental tests and calculated by the relationships established by the Brazilian Standard ABNT NBR 7190:1997. By the results of the hypothesis tests, it was possible to conclude that the estimate of the embedment strength parallel to the grain proposed by the Brazilian standard ABNT NBR 7190:1997, establishing equivalence with the strength compression results in the same direction, must be effective to the wood species Pinus taeda L., however, the same was not found in the perpendicular direction with respect to the grain, possibly explained by the alpha(e) values in the equation to calculed fe(90)

Efeitos de ensino envolvendo equivalência entre palavra ditada, palavra escrita e objeto sobre a inteligibilidade da fala em adolescente com hipoplasia cerebelar

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise documental: concepções do universo acadêmico brasileiro em Ciência da Informação

Considering document analysis as one of the theoretical approaches of information organization, besides subject cataloguing and indexing it carries out a theoretical research on its conceptual dimension as a background to a further analysis of the Brazilian academic environment specially in terms of conceptions of document analysis as well as its interdisciplinary relationships. The results reveal a strong theoretical influence of Jean-Claude Gardin´s ideas which are deeply devoted to the processes involved in document analysis. It also confirms the high level of interdisciplinary relationships to Logical-linguistic disciplines. Neverthless, it feels the need of the Brazilian researches in assuming their theoretical influences in such a way to minimize the huge terminological diversity while naming the specific concepts of the area.

Escolhas de letras nas primeiras escritas infantis: função e unidade no discurso

The article deals, initially, from a theoretical point of view, the concept of function in the perspective of Vygotsky (2001), and functional equivalence from the point of view of Smith (1989) and articulates them with the letter funcion in the construction of words in discursive statements. Taking as reference these concepts, it was analysed writings of a student in early literacy at a school in a countryside city in the state of São Paulo, in a situation of writing letters of personal correspondence, whose data were collected in 2009 in order to determine which letters are chosen by the student and why they are chosen to record the speech. The concept of function in Vygotsky and the functional equivalence of Smith (1989) used for the analysis of corpus, revealed that the student’s decisions are characterized by diversity sources and criteria, and rely mainly on the basis that a letter can have the constitution of the word, in the process of enunciation, regardless of their phonetic correspondence. The letter, used as a basis, would lose its status as strictly technical element to achieve the status of a unit of sense since is a constituent part of discourse.

Memória organizacional, memória corporativa e memória institucional: discussões conceituais e terminológicas

The proposal of present paper is to present a conceptual and terminological discussion relative to the terms: organizational memory, corporate memory and institutional memory that is a subject still little studied and explored in the academic area. The study is theoretical focus and the research kind is bibliographical. As research sources were utilized: books, digital libraries of theses and dissertations in the scope of the country and CAPES Journals Portal. This study is in course and is part of doctorate research "Organizational memory and the knowledge bases constitution". As the partial results, observes that the question about "memory" is studied by different areas of knowledge: Psychology, Neurosciences, History and others; the concepts about organizational memory and corporate memory are studied by Administration and Information Systems areas; the concept of institutional memory is more studied by Business Communication area focusing the company history. Beyond that, observes the use of another term, social memory, utilized by Information Science and History areas.

Grupos wallpaper e sua relação com cohomologia de grupos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Thermal effective Lagrangian of generalized electrodynamics in static gravitational fields

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Normal Forms for Codimension One Planar Piecewise Smooth Vector Fields

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

C-l-contact and C-l-right equivalences of real semi-quasihomogeneous C-l function germs

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

O léxico da apicultura e da melinponicultura no Brasil: limites e flexibilidade para sua fixação em um dicionário terminológico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Expressões Idiomáticas bilíngues relativas ao campo lexical do vestuário: uma reflexão sobre suas metáforas e metonímias

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A prática contemporânea de tradução com auxílio de sistemas de memórias e os limites da responsabilidade do tradutor

This paper analyzes the growing adoption of translation tools by the contemporary translator working for markets such as the localization industry. The fast turnaround pace of translation of electronic texts ends up conditioning the employment of translators to their ability to use the resources provided by tools such as translation memories systems efficiently. These systems, as envisioned in their early conception, would allow users to increase productivity and, simultaneously, standardize their terminological production. Seeking to go beyond the predominantly descriptive approaches of these tools, some theoretical assumptions upholding the use of translation memories are examined. From this perspective, the translator’s involvement with the work in progress is analyzed, mainly when this professional is part of a larger process of production and distribution of information by electronic means and for diverse audiences. Ultimately, the consequences of the employment of these tools are taken into consideration, such as those between translator/translation and translator/client, as well as the extension of the responsibility of the translator dedicated to developing partially automated translations.