On the Structural Behavior of Composite Beams Using Cold-formed Shapes

Cold-formed shapes have been increasingly employed in the construction of small multiple-floored buildings in Brazil, because wide flange shapes required to meet the demand are unavailable on the Brazilian market. Because existing codes fail to cover the design of composite beams constituted of cold-formed shapes, Brazilian design engineers have usually disregarded the contribution of the slab or have adopted improvised calculations that may to lead to unsafe results. The structural behavior of composite beams, constituted of cold-formed double channel shapes and connected to the concrete slab by means of shear connectors that were also cold-formed, was investigated experimentally. Simply supported beams were tested in which the degree of connection (number of connectors) and the type ofload (concentrated or distributed load) were varied. The results were then compared to those obtained through classic theoretical models of composite beam design, which supplied relevant conclusions for the design of these elements

Cold-formed Shear Connectors for Composite Constructions

Construction employing composite steel-concrete structures has been increasingly applied in building and bridge structures, and solutions involving cold-formed profiles have recently appeared which, in many cases, have resulted in reduced costs. Because constructions using composite steel-concrete structures, involving cold-formed profiles, are not covered by current Brazilian Codes, it is necessary to investigate the issue. This paper, therefore, presents the results of an experimental analysis (24 push-out tests) made for two types of connectors: U-profile and angle, with two plate thicknesses: 2.65 mm and 4.76 mm, evaluating their strength and their load-slip behavior. The tests were performed on test specimens adapted to those proposed by the British Standard BS 5400 - part 5 and by EUROCODE 3

Free algebras generated by symmetric elements inside division rings with involution

This is a joint work with Vitor O. Ferreira and Jairo Z. Gon ̧calves. For any Lie algebra L over a field, its universal enveloping algebra U (L) can be embedded in a division ring D (L) constructed by Cohn [?] (and simplified later by Lichtman [?]). If U (L) is an Ore domain, D (L) coincides with its ring of fractions. Consider now the principal involution of L, L → L, x 7→ − x. It is well known that the principal involution of L can be extended to an involution of U (L). It was proved by Cimpric, that this involution can be extended to D (L) [?]. For a large class of noncommutative Lie algebras L over a field of zero charac-teristic, we show that D (L) contains noncommutative free algebras generated by symmetric elements (with respect to the extension of the pri ncipal involution). This class contains all noncommutative Lie algebras over a field of zero characteristic such that U(L) is an Ore domain

The relationship between socioeconomic level and mathematics proficiency of 9th grade students from Pernambuco through Educational Data Mining

O desempenho escolar dos estudantes da educação básica, mensurado pelo Ideb a partir dos índices de aprovação das instituições escolares e de proficiência no Saeb (Prova Brasil), possui relação com aspectos sociais, como: renda familiar, trabalho doméstico, nível de escolaridade dos pais, dentre outros. Nesse sentido, esse trabalho tem como propósito demonstrar o quanto os aspectos relativos aos Índices de Nível Socioeconômico (Inse) afetam a proficiência em matemática dos estudantes dos Anos Finais das escolas públicas do Estado de Pernambuco. Para tal, aplicou-se técnicas de mineração de dados sobre os microdados coletados no banco de dados do INEP. Os resultados demonstram uma diferença estatisticamente significativa entre proficiências de matemática dos estudantes de Inses diferentes e destaca os tópicos socioeconômicos mais relevantes relacionados ao desempenho no Saeb.The Basic education student's performance, measured by Ideb based on the approval rates of school institutions and proficiency in the Saeb (Brazilian National Exams), is related to social aspects, such as: family income, domestic work, parents' education level, among others. In this sense, this work is focused on demonstrating how aspects related to the Socioeconomic Level Index (Inse) affects the Final Years of public schools student's proficiency in mathematics in the State of Pernambuco. To this end, educational data mining techniques were applied to the microdata collected on the INEP's database. The results demonstrate a statistically significant difference between the student's math proficiencies belonging to different Inses and highlight the most relevant socioeconomic topics related to performance on the Saeb

ALTERNATING UNITS AS FREE FACTORS IN THE GROUP OF UNITS OF INTEGRAL GROUP RINGS

Let G be a group of odd order that contains a non-central element x whose order is either a prime p >= 5 or 3(l), with l >= 2. Then, in U(ZG), the group of units of ZG, we can find an alternating unit u based on x, and another unit v, which can be either a bicyclic or an alternating unit, such that for all sufficiently large integers m we have that < u(m), v(m)> = < u(m)> * < v(m)> congruent to Z * Z.CNPq[303.756/82-5]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP-Brazil[00/07.291-0]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP[06/59817-2]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP