RESUMO
Natural fibers used as reinforcements or fillers for materials development greatly affect properties and performance of end-use applications. As a consequence of conditioning processes such as grinding and sieving, average fiber length varies significantly. It is thus necessary to estimate the length as statistical data distribution rather than a single mean value. This approach implies length measurement of a significant number of fibers; however, a very high number of data points requires not only long-time frames but also significative amount of work. To address these issues, this article details a facile methodology to measure the length of a large number of natural fibers of oil palm empty fruit bunch (OPEFB) together with a statistical analysis to verify the correspondence between theoretical distributions and experimental data. Moreover, further information related to spectrophotometric, physico-chemical, mechanical, thermal, and morphological characteristics of OPEFB fibers coming from oil palm cultivation in Ecuador are presented. The data will contribute to comprehensively and rigorously describe the overall effects of natural fiber lengths on material properties.
RESUMO
In this paper a study on the process of densification of oil palm empty fruit bunches (OPEFB) is presented. An empirical-statistical model that allows the evaluation of densification process is obtained through an experimental factorial design. The main purpose of the experimental arrangement is to find the appropriate reference values for the experimental factors - moisture content, fiber length and compaction time-with which optimal performance responses of briquettes are achieved. Statistical models are obtained that explain in an acceptable way the influence of independent experimental factors on the mechanical properties of briquettes, such as briquettes density, durability index and compressive strength. It is possible to conclude that briquettes manufactured with the appropriate reference values, moisture content of 8% w.b., fiber length of 73.6 mm and a compaction time of 26.6 s respectively, meet mechanical and thermal requirements that are required in the most representative standards for biomass briquettes for energy purposes. Results obtained in the current investigation can be used as reference for the design of an industrial pilot plant destined to the densification of EFB of African oil palm.
RESUMO
Abstract: Pheidole is a genus with wide geographical distribution and diversity, especially in the leaf litter of neotropical forests, where nests are found at the soil-litter interface, in the soil and vegetation, among leaves, seeds, and twigs. Despite the availability of twigs and Pheidole species diversity in the leaf litter, most of this resource is not occupied, which suggests the existence of filters. This study analyzes whether twigs occupied by Pheidole species differ for the outer structure and anatomy of the wood. Twigs were collected from preserved Atlantic Forest fragments in southeastern Brazil. Twigs with Pheidole colonies were measured and the wood anatomy analyzed. We collected 224 twigs with Pheidole colonies, but the analysis was done at 41% due to wood decomposition. Five species were recorded in these twigs, which differ for the outer structure and anatomy of the wood. These results suggest the existence of preference in the occupation of twigs determined by wood structure.
Resumo: Pheidole é um gênero com ampla distribuição geográfica e diversidade, especialmente na serapilheira das florestas da Região Neotropical, onde os ninhos são encontrados na interface solo-serapilheira, solo, vegetação, entre folhas, sementes e galhos. Apesar da disponibilidade de galhos e diversidade de espécies de Pheidole na serapilheira, a maior parte deste recurso não é ocupada, o que sugere a existência de filtros. Neste trabalho analisamos se galhos ocupados por espécies de Pheidole diferem em relação à estrutura externa e anatomia da madeira. A coleta de galhos foi realizada em fragmentos conservados de Mata Atlântica na região Sudeste do Brasil. Os galhos com colônias de Pheidole foram mensurados e a anatomia da madeira analisada. Foram coletados 224 galhos com colônias de Pheidole, mas a análise foi realizada em 41% devido à decomposição da madeira. Nestes galhos foram registradas cinco espécies, que diferem em relação à estrutura externa e anatomia da madeira. Estes resultados sugerem a existência de preferência na ocupação do galho determinada pela estrutura da madeira.
RESUMO
Upland cotton fiber is one of the most used natural fibers in the production of textile materials worldwide. For this reason, the selection of genotypes that meet the industry's requirements is one of the main goals of cotton breeding programs. This study aimed to estimate the phenotypic and genotypic correlations among fiber traits and identify the direct and indirect effects of these traits on seed cotton yield of upland cotton genotypes in the semi-arid Brazilian Northeast. This study assessed 21 upland cotton genotypes from a complete diallel cross without reciprocals. The design was randomized blocks, with three replications and 21 treatments. The experiment was conducted in the municipality of Patos - PB, in 2015. The statistical analysis consisted of analysis of variance by the F test, phenotypic and genotypic correlation analysis, and path analysis. The studied materials revealed genetic variability for all traits. Path analysis has shown that the traits fiber elongation, fiber strength, and fiber fineness have a direct positive effect on seed cotton yield.
A fibra do algodoeiro herbáceo é uma das fibras naturais mais utilizadas na produção de materiais têxteis no mundo. Portanto, a seleção de genótipos que atendam às exigências desta indústria é um dos principais objetivos dos programas de melhoramento do algodoeiro. O objetivo deste estudo foi estimar as correlações fenotípicas e genotípicas entre as características tecnológicas da fibra e identificar os efeitos diretos e indiretos destas características sobre a produtividade de algodão em caroço de genótipos de algodoeiro herbáceo no semiárido nordestino. Foram avaliados 21 genótipos de algodoeiro herbáceo provenientes de um cruzamento dialélico completo sem os recíprocos. O delineamento utilizado foi blocos completos ao acaso, com três repetições. O experimento foi conduzido no município de Patos - PB, em 2015. As análises estatísticas consistiram de análise de variância pelo teste F, análise de correlação fenotípica e genotípica e análise de trilha. Todas as características apresentaram variabilidade genética entre os genótipos estudados. A correlação fenotípica foi positiva entre CSP, COMP, UNF e RES. Foram observados efeitos indiretos de ALON, COMP e FIN sobre PROD, por meio das variáveis FIN, RD e +b.