Estudo analítico da estabilidade dimensional longitudinal das espécies de madeira tropicais brasileiras

Brazil owns a large vegetal covering and the best utilization of these materials requires physical and mechanical characterization procedures. Equations found in the literature make easier the wood properties determination. At this context, well known authors developed the equation βl = βt/23, being βl and βt the longitudinal and tangential shrinkage percentages, for βl estimation based on the βt value specially for wood species from the Northern hemisphere. This paper aims to investigate the accuracy of this equation for fifteen tropical Brazilian wood species covering the entire range of hardwood strength classes according to the Brazilian Normative ABNT NBR7190. The average experimental values of βl and βt were 7.71% (CV = 26,71%) and 0.73% (CV = 38,76%), respectively. The non-parametric Kruskal-Wallis ANOVA refuted the hypothesis of equivalence between theoretical and experimental βl values (p-value = 0.0000). A linear regression model fitted to experimental values provided βl = βt/9,84 as optimal solution (p-value = 0.0000, R2 = 47,23%). According to results it is possible to conclude that the value of longitudinal shrinkage percentage of tropical Brazilian wood species is statistically 2,34 times greater than the value found in the literature, which impacts the design of timber structures procedures increasing the internal stresses in timber structural elements.O Brasil possui grande cobertura vegetal e o melhor aproveitamento desses materiais requer procedimentos de caracterização física e mecânica. Equações encontradas na literatura facilitam a determinação das propriedades da madeira. Nesse contexto, autores conhecidos desenvolveram a equação βl = βt/23, sendo βl e βt as porcentagens de retração longitudinal e tangencial, para estimativa de βl com base no valor de βl especialmente para espécies de madeira do hemisfério Norte. Este trabalho tem como objetivo investigar a precisão desta equação para quinze espécies de madeiras tropicais brasileiras cobrindo toda a faixa de classes de resistência da madeira de lei de acordo com o Norma Brasileira ABNT NBR 7190. Os valores experimentais médios de βl e βt foram 7,71% (CV = 26,71 %) e 0,73% (CV = 38,76%), respectivamente. A ANOVA não paramétrica de Kruskal-Wallis refutou a hipótese de equivalência entre os valores de βl  teórico e experimental (p-valor = 0,0000). Um modelo de regressão linear ajustado aos valores experimentais forneceu βl  =βt/9,84 como solução ótima (p-valor = 0,0000, R² = 47,23%). De acordo com os resultados, é possível concluir que o valor da porcentagem de retração longitudinal das espécies de madeira tropical brasileira é estatisticamente 2,34 vezes maior que o valor encontrado na literatura, o que impacta nos procedimentos de dimensionamento de estruturas de madeira aumentando as tensões internas nas estruturas de madeira

PARTICIPAÇÃO E DESENVOLVIMENTO: UMA ANÁLISE DO PERFIL DOS REPRESENTANTES DO CONSELHO MUNICIPAL DE DESENVOLVIMENTO RURAL SUSTENTÁVEL DE DIAMANTINA, MINAS GERAIS

A região do Vale do Jequitinhonha apresenta uma grande riqueza cultural, embora seja uma das regiões mais pobres do Estado de Minas, o que pode ser corroborado conforme seu índice de Desenvolvimento Humano - IDH, oscilando em torno de 0,465. Este espaço é caracterizado pela marcante presença de agricultores familiares, representando cerca de 50% do total da população economicamente ativa da região. O presente artigo propõe discutir a formação e atuação dos Conselhos Municipais de Desenvolvimento Rural Sustentável - CMDRS enquanto espaços propulsores de ações interventoras mais efetivas quanto às necessidades das comunidades rurais; para tanto se toma como unidade desta análise o CMDRS de Diamantina - MG. Para composição deste trabalho foram efetuadas entrevistas com informantes chaves, quer sejam, os conselheiros, bem como o uso do método de observação participante. A principal inovação analisada foi a democracia participativa, ressaltando-se, entretanto, alguns entraves a sua efetivação e que dizem respeito às dificuldades de representação dos agricultores frente ao intercâmbio com os representantes de organizações governamentais, o que ocasionam níveis de interação diferenciados no âmbito deste Conselho. Superando-se esses entraves, as interações constituem ponto de partida para formulação das estratégias de planejamento e gestão dos agricultores familiares.--------------------------------------------The area of the valley of Jequitinhonha presents a great cultural wealth, although it is one of the areas more poor of the State of Minas Gerais, what can be corroborated her index of Human Development accordingly - IDH, oscillating around 0,465. This space is characterized by the outstanding presence of family farmers, acting about 50% of the total of the population economically active of the area. The present article intends to discuss the formation and performance of Municipal Council of Maintainable Rural Development - CMDRS while spaces propellers of actions more effective intervenors as for the needs of the rural communities; for so much it is taken about unit of this analysis CMDRS of Diamantina - MG. For composition of this work interviews were made with key informers, he wants are, the counselors, as well as the use of the method of participant observation. The main analyzed innovation was the democracy participation, being stood out, however, some impediments his execute and that they concern the representation difficulties of the farmer’s front to the exchange with the representatives of government organizations, what causes interaction levels differentiated in the extent of this Council. Being overcome those impediments, the interactions constitute starting point for formulation of the planning strategies and the family farmers' administration.Agricultura familiar, Planejamento Rural, Política Local, Vale do Jequitinhonha, Family agriculture, Rural planning, Local politics, Valley of Jequitinhonha, Community/Rural/Urban Development, Farm Management,

Properties of concrete manufactured with use of ceramic sanitary ware waste as aggregate

In concrete manufacture, cement (Portland type is the most used), water and aggregates (classified intocoarse and fine) are used. With the use of several raw materials the generation of waste is inevitable, both inconstruction and in other sectors, such as the industries producing ceramic materials. Among the types ofwaste from such industries, can be mentioned the ceramic scrap (from the sanitary ware industry). Accordingto the above, the aim of this research was to study the addition of ceramic scrap as a coarse aggregate in differentproportions in the concrete formulation. In order to do this, was select wastes from an industry in thesouth of Minas Gerais (Brazil), and prepare specimens to determine the fresh (slump test, adhesiveness andporosity) and hardened (compression strength) of concrete. Were fabricated five concrete formulations, onereference (RC) and four with ceramic scrap substituted for coarse aggregate in the proportions of 25% (CSCI),50% (CSC-II), 75% (CSC-III) and 100% (CSC -IV). Fresh concretes, two formulations did not show adhesiveness(CSC-III and CSC-IV) and two a small water runoff (CSC-I and CSC-II), however, without compromisingthe concrete’s workability. Regarding the compression strength, the average values presented werevery good, including the formulation with 100% ceramic scrap (fc = 47.78 MPa). Another important aspectobserved in the rupture modes was the small adhesion between the ceramic scrap and the mortar due to theglazing in the contour of the waste. As for the porosity of the concretes, those with 25%, 75% and 100% ofceramic scrap in their composition presented lower values than the reference concrete.Keywords: Ceramic scrap; Concrete; Waste; Mechanical properties

Propriedades físicas e mecânicas da madeira Tatajuba (Bagassa guianensis) proveniente de duas diferentes regiões brasileiras

Como consequência dos fatores edafoclimáticos, as propriedades da madeira podem ser influenciadas deacordo com a região de desenvolvimento da árvore. O objetivo do presente trabalho consistiu em verificar ainfluência da região de extração de lotes da madeira de Tatajuba (Bagassa guianensis), provenientes de duasdiferentes regiões do Brasil (Alta Floresta e Bonfim do Sul, municípios dos estados de Mato Grosso e Roraima,respectivamente), ao teor de umidade de 12%, em algumas de suas propriedades físicas e mecânicas.Para cada um dos lotes foram determinadas duas propriedades físicas e cinco propriedades mecânicas, deacordo com a norma ABNT NBR 7190:1997. Para avaliar a influência da região de extração nas propriedades,foi realizada a análise de variância de Kruskal-Wallis, considerando resultados significativos (valoresnão equivalentes) aqueles que atendiam à condição P-valor 0,05. De acordo com os resultados da análiseestatística, os diferentes lotes da mesma espécie de madeira apresentaram valores médios das propriedadesestudadas equivalentes em relação ao conjunto composto por todas as madeiras, porém, os valores médios daresistência na compressão paralela (fc0) e da densidade aparente não foram significativos entre as duas regiões.Os valores característicos da fc0 foram diferentes para os lotes das duas regiões, ao teor de umidade de12%, implicando em classes de resistência diferentes (D50 – Alta Floresta e D60 – Bonfim do Sul).Palavras-chave: Caracterização; Classes de resistência; Estruturas de madeira; Floresta Amazônica

Rapid detection of Vancomycin-Resistant Enterococci (VRE) in rectal samples from patients admitted to intensive care units

ABSTRACT: The reduction in time required to identify vancomycin-resistant enterococci (VRE) has gained increased importance during hospital outbreaks. In the present study, we implemented a laboratory protocol to speed up the VRE screening from rectal samples. The protocol combines a medium for selective VRE isolation (VREBAC®, Probac, São Paulo) and a multiplex PCR for detection and identification of vanA and vanB resistance genes. The screening performance was analyzed in 114 specimens collected from four intensive care units. The swabs were collected at two periods: (1) during a VRE outbreak (February 2006, n=83 patients) and (2) at the post-outbreak period, after adoption of infection control measures (June 2006, n=31 patients). Forty-one/83 VRE (49.4%) and 3/31(9.7%) VRE were found at the first and second period, respectively. All isolates harbored the vanA gene. In both periods, detection of the gene vanA parallels to the minimum inhibitory concentration values of >256 µg/mL and >48 µg/mL for vancomycin and teicoplanin, respectively. Multiplex PCR and conventional methods agreed in 90.2% for enterococci identification. Besides this accuracy, we also found a remarkable reduction in time to obtain results. Detection of enterococcal species and identification of vancomycin resistance genes were ready in 29.5 hours, in comparison to 72 hours needed by the conventional methods. In conclusion, our protocol identified properly and rapidly enterococci species and vancomycin-resistance genes. The results strongly encourage its adoption by microbiology laboratories for VRE screenning in rectal samples

Comparative Study Between Theoretical and Experimental Values of Dimensional Quantities for Tropical Brazilian Wood

Brazil presents many wood species that are very useful in several sectors such as civil construction and furniture industry. Rational use of wood resources depends on the wood characterizations process, that can become easier using equations involving properties of interest. Some theoretical equations found in the literature were developed for primarily softwood from the northern hemisphere, but not checked regarding of their accuracy for tropical Brazilian wood species. This paper aims to confront four theoretical equations with the dimensional stability quantities of fifteen tropical Brazilian woods and test the accuracy of them for these wood species. Results showed that experimental values present greater variability than the ones provided by the theoretical equations. Kruskal-Wallis ANOVA performed showed that one of the four equations cannot be accurately used for tropical Brazilian wood species at 5% significance level. Keywords: Accuracy. Material. Physical properties. Wood.

Herbage Intake, Methane Emissions and Animal Performance of Steers Grazing Dwarf Elephant Grass with or without Access to \u3cem\u3eArachis pintoi\u3c/em\u3e Pastures

The inclusion of legumes in diets based on grass has nutritional benefits due to ingestive and digestive interactions (Niderkorn and Baumont 2009). Moreover, it is speculated that tropical legumes can contribute to reducing the emission of greenhouse gases (GHG) compared to diets exclusively composed of grasses (Archimède et al. 2011). However, under grazing conditions, these advantages are not always possible to obtain. This occurs when the spatial distribution of sward grasses impose limitations on access to legumes by grazing animals (Solomon et al. 2011). This can be the case, for example, when legumes are overlapped by the leaves of a tufted tall grass, as dwarf elephant grass (Crestani et al. 2013). Considering that management strategies for increasing legumes in the diet of grazing animals should be better studied and data on enteric methane emitted by ruminants eating tropical forages are scarce, the aim of this work was to evaluate the effect of access to an exclusive area of peanuts (Arachis pintoi cv. Amarillo) for cattle grazing dwarf elephant grass (Pennisetum purpureum cv. BRS Kurumi) on herbage intake, animal performance and enteric methane emission

Fatigue performance of laser welds in heavy-gage press hardening steels

This work investigates and compares the fatigue performance of laser-welded joints of two press hardening steels: a standard 22MnB5 and a variant modified by a combination of niobium and molybdenum (NbMo) alloying. The results indicate that joint geometry aspects, superposed to an intrusion-generated damage mechanism, were prevalent in causing a poor fatigue life in the case of peak stress values greater than 11% of the base metal's ultimate strength being around 1450 MPa. As identical process procedures were employed, the tests allowed investigating the influence of the alloy design on fatigue performance. The results of geometrical analysis and fatigue tests indicated that the NbMo modified alloy performed better than the standard 22MnB5 steel. The results also suggest that, if extremely tight quality limits are used in the manufacturing procedures, laser-welded joints of press hardened steels could offer a very favorable fatigue performance being considerably better than that of conventional and high strength structural steels

Avaliação das estruturas de cobertura em madeira de um galpão de estoque de produtos químicos

Este trabalho tem com objetivo avaliar a integridade das estruturas que fazem parte da cobertura de um galpão de 70 anos, destinado ao estoque de produtos químicos, localizada no Estado de São Paulo (Brasil), e apontar possíveis soluções para os problemas identificados. Buscou-se estimar a influência dos resíduos dos produtos químicos depositados nas superfícies dos elementos estruturais e identificar a espécie de madeira utilizada no projeto, por meio de ensaios físicos (densidade aparente) e mecânicos (compressão e cisalhamento paralelo às fibras. Os problemas identificados foram: (a) umidade devido a telhas quebradas; (b) deterioração superficial da madeira em função de reação química entre os produtos armazenados e a estrutura; (c) cavilhas de madeira com instalação incompleta; (d) falta de mãos-francesas em algumas terças; (e) travamento inadequado das treliças; e (f) deterioração de pregos de fixação por oxidação. Pelas observações realizadas, as soluções indicadas são de fácil execução, pois as estruturas não foram severamente prejudicadas. Com relação à espécie de madeira, os resultados das propriedades mecânicas obtidas associadas à densidade aparente apontaram para a espécie Peroba-Rosa (Aspidosperma polyneuron). A análise estatística de resultados apontou para a não influência do produto químico no desempenho da estrutura do telhado

External Skeletal Fixator Intramedullary Pin “Tie-in” for the Repair of Comminuted Tibial Fracture in a Brazilian Fox (Pseudalopex vetulus)

Background: The Brazilian fox (Pseudalopex vetulus, Lund 1842) is a naturally endemic specie of the Brazilian savana vegetation. Due to the rapid destruction of its habitat, the specie is considered “vulnerable” and subject to different kinds of trauma that usually results in fractures and dislocations. Among the methods of fractures fxation, highlights the external skeletal fxator intramedullary pin “tie-in” which consists of the intramedullary pin associated to the external fxator. The aim of the present report was to describe the case of a Brazilian fox with a comminuted tibial fracture, submitted to osteosynthesis using an external skeletal fxator intramedullary pin “tie-in”. Case: It was attended an exemplar of Pseudalopex vetulus, male, young adult, with 3.9 kg body weight and history of functional impotence of the left hindlimb. At the physical and orthopedic evaluations were observed loss of bone continuity and crepitus in tibial region, and the presence of a contaminated lacerating skin wound about 3 cm in diameter in the lateral side of the injured limb. Craniocaudal and mediolateral radiographic projections of the left hindlimb revealed the presence of a complete comminuted fracture at the proximal and distal shaft of the left tibia; and a complete transverse fracture at mid shaft of the left fbula. Due to this, the animal was submitted to fracture fxation using an external skeletal fxator intramedullary pin “tie-in”. For the surgical procedure, broad trichotomy and antisepsis of the left hindlimb were performed, followed by a longitudinal incision on the medial side of the tibia. After bone fragments identifcation, was realized the retrograde positioning of a Steinmann pin of 3.0 mm in diameter toward the proximal epiphysis. Subsequently, the pin was externalized in the parapatelar region and then replaced toward the distal epiphysis. The intramedullary pin was not cut, but folded and attached to the transcortical pins of the unilateral external skeletal fxator using polymethylmethacrylate acrylic resin. For the unilateral external skeletal fxator were placed four Kirschner pin of 1.5 mm in diameter. Of these, two pins were placed at the proximal bone segment of the fracture, and two at the distal one. The central bone segment was not transfxed by pins. Radiographic postoperative examination revealed fracture reduction with good alignment of the bone fragments. The metallic implants were also well positioned. Bone healing was verifed at 150 days postoperatively. At this moment, radiographic examination revealed calcifed and ossifed bone callus, and the maintenance of bone axis.The animal was reintroduced to nature. Discussion: The external skeletal fxator intramedullary pin “tie-in” features biomechanical superiority to both intramedullary and external skeletal fxator pin, since it resists to rotational, bending and axial forces that act at the fracture. Additionally, it is a less expensive fracture fxation method, especially when replacing the lateral connecting rod by polymethylmethacrylate acrylic resin. It was concluded that the external skeletal fxator intramedullary pin “tie-in”can be considered viable in small wild mammals, such as the Brazilian fox (Pseudalopex vetulus), since it enabled the bone healing and the limb functionality. Further studies with a greater number of individuals, however, are necessary to evaluate the real applicability of the fracture fxation method.Keywords: traumatology, osteosynthesis, wild animals