Compression molding process was used to manufacture composites reinforced with pineapple-leaf fibers. During manufacturing, four plies of polypropylene with an average thickness of 0.76 mm were used and the fibers were equally distributed between plies to generate a stacked composite with the fibers in external layers transversally oriented to those in the inner layer. Two types of pineapple-leaf fibers were used as reinforcement: untreated fibers and fibers modified in an alkali solution (10% NaOH). Two different fiber contents were also evaluated in order to measure their effect on the mechanical properties of the composite. Ultimate tensile strength, strain at maximum load, Young's modulus, flexural strength and flexural modulus were measured. Tensile strength was increased 22% and Young's modulus increased 60%. Flexural strength and flexural modulus increased 19 % and 50% respectively, with fiber content. However, the alkali treatment did not improve those properties. Fractured surfaces of the composites were examined using electron microscopy and failure mechanisms such as fiber pullout and matrix deformation were observed.
Objetivo: Realizar el inventario de las angiospermas no arbóreas del bosque El Caraño, localizado en el piedemonte Andino Amazónico de Colombia, el cual incluye la lista de especies, síndromes de dispersión, categorías de amenaza, endémismos y novedades corológicas. Alcance: Caracterizar las angiospermas no arbóreas de El Caraño como herramienta de ordenamiento territorial. Metodología: Se recolectaron muestras botánicas entre junio de 2015 y mayo de 2016, registrando sus hábitos de crecimiento y recopilando información sobre sus síndromes de dispersión, categorías de amenaza, endemismos y novedades corológicas. Principales resultados: Se registran 319 taxones, pertenecientes a 165 géneros y 68 familias, las eudicotiledóneas representan el 58% de la flora, mientras que las monocotiledóneas y angiospermas basales agrupan el 35% y 7% respectivamente. Araceae presenta el mayor número de géneros y especies (6/31). Piper andakiensis y Philodendron edwinii son endémicas, 49 especies son novedades corológicas para el departamento del Caquetá y 19 para la Amazonia colombiana. Adicionalmente, tres especies nuevas están siendo descritas. Treinta taxones registran alguna categoría de amenaza, de los cuales Orchidaceae registró el mayor número de especies en peligro de extinción (21 spp.). La zoocoria se presentó como el síndrome de dispersión dominante (72% de las especies). Conclusiones: La diversidad florística de El Caraño representa una transición entre la Amazonia y los Andes, lo cual se señala no solo por su composición, sino también, por el considerable número de taxones registrados. Lo anterior, sumado a las especies endémicas, novedades corológicas y taxonómicas, contrasta con los pocos taxones evaluados que cuentan con alguna categoría de riesgo y a la avanzada deforestación de la zona, promoviendo que la ignorancia de estos recursos derive en la perdida de la flora colombiana. Se espera que este documento soporte futuros programas de conservación y ordenamiento del territorio, basados en la diversidad de su flora y endemismo.
A new species of Lepanthes from the Eastern Andes of Colombia is described and illustrated. Lepanthes florenciana is most similar to Lepanthes niphas, but it can be distinguished by the petals transversely trilobed with the upper and lower lobe dolabriform (vs. transversely bilobed with the lobes narrowly triangular), a lunate lip blades (vs. semi-orbicular) and an oblong pubescent appendix (vs. a minute apiculum in the sinus).
A narrowly endemic new species of Glossoloma is described from the Cordillera Oriental of the northern Andes, in the Colombian departments of Caquetá and Huila. Glossoloma magenticristatum J.L.Clark, D.Hoyos & Clavijo, sp. nov. differs from most other congeners by a habit that is usually epiphytic with elongate scandent subwoody shoots, the presence of a magenta corolla tube, and a creased calyx formed by tightly appressed adjacent lobes. A brief summary of Gesneriaceae diversity in the Colombia departments of Caquetá and Huila is discussed with an emphasis on the old highway between Florencia and Guadalupe. The conservation status of G. magenticristatum is assessed as Endangered (EN) based on IUCN Criteria.
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