Bending in laminas of NFPR: type of reinforcement, fracture and properties

Natural fiber reinforced plastics (NFRP) have awakened considerable interest in the area of polymer composites, because of the need to develop new, environmentally friendly materials. One of the most complex ways of manufacturing this type of material is in the form of ultrathin laminar layers; however, this process hinders mechanical testing, mainly three and four-point bending. The present investigation faces this challenge and shows the influence of parameters, such as the grammage of reinforcing fabric and lamination process, on strength, stiffness and fracture characteristics for three-point bending in this type of structural element. The industrially manufactured laminas were composed of orthophthalic polyester resin reinforced with licuri fibers. Macromechanical and micromechanical analyses were conducted in the study of fracture characteristics for all the parameters. The mechanical behavior in the three-point bending of the laminar composite showed that the use of licuri fiber to obtain natural fiber-based plastic is completely viable

Intake and digestibility of silages containing pineapple pulp and coast-cross hay with or without urea and markers recovery in sheep

ABSTRACT The objective of this study was to evaluate the intake and digestibility of silages containing pineapple pulp and coast-cross hay, with or without addition of urea, and the recovery of the markers chromium oxide (Cr2O3), indigestible neutral detergent fiber (iNDF), indigestible acid detergent fiber (iADF), and indigestible dry matter (iDM), in a digestibility assay, in sheep. Treatments were as follows: two levels of pineapple pulp (818 and 758 g kg−1) and two levels of urea (with and without urea), in a completely randomized design. Twelve sheep (three per treatment) were used, kept in metabolic cages. Fecal excreta were determined by total collection or estimated by using the markers. Marker samples were obtained in morning and afternoon collections, with mean concentrations obtained for both daily activities. The level of silage pulp did not affect intake, while addition of urea increased the intake of crude protein (CP), but did not influence the intakes of dry matter, organic matter, neutral detergent fiber, or acid detergent fiber. The digestibility coefficients of all afore-mentioned fractions increased with the increase in pulp, the same happening with the addition of urea. The internal marker with lowest variability among the internal markers was iADF, with mean values near 100%. Mean recovery of Cr2O3 was approximately 107%, but with lower variability among treatments. Inclusion of pineapple pulp in silage does not influence intake, while addition of urea only increases the intake of CP. The levels of pineapple pulp in silage with or without urea increase the digestibility of the silage. Indigestible acid detergent fiber is the marker with lowest variability of recovery, with mean recovery for the four silages used very close to 100%