Palm fibers were immersed in sea water for 1, 2, 3, and 4 weeks prior to application as reinforcement of green biocomposite. Instead of common resin matrix, natural sago starch was applied as the matrix compound. The immersion treatments had significantly affected fibers surface morphology and interfacial bonds of fiber and the matrix as observed through Scanning Electron Microscopy (SEM). The quality of interfacial bonds became higher by additional duration of the sea water immersion. The best interlocking surfaces of fibers and matrix appeared in the composite with 4-week immersed fibers, indicated by disappearance of gaps between fiber and matrix. The morphology of fibers surface interlocking process was clearly seen during the duration of immersion.

This communication reports the results of a pilot study on the sound absorption characteristics of chicken feathers (CFs). Recently, demands for natural and sustainable materials have been extensively studied for acoustical purposes. CF has long been left wasted, however, they can be used for sound-absorbing purposes to improve acoustical environments as a sustainable and green acoustical material. In order to clarify their feasibility, samples of CF absorbers of various densities and thicknesses were prepared, and their sound absorption coefficients were measured by the standard impedance tube method. The measured results were also compared with those of conventional glass wools of the same densities and thicknesses. The results show that CFs have potentially good sound-absorption performance, which is similar to typical fibrous materials: increasing with frequency. Results of direct comparison with glass wool demonstrate that the absorption coefficients of CFs are comparable and, at some frequencies, somewhat higher than conventional glass wools in some cases. Additionally, the first step for searching a prediction method for the sound absorption performance of CFs, their flow resistivity was measured and a Delany–Bazley–Miki model was examined. However, the resultant flow resistivity was unexpectedly low, and the model gave only a much lower value than that measured. The reason for the discrepancies is the subject of a future study.

This study aims to identify the effect of liquid smoke treatment on surface morphology and tensile strength of sago fiber (SF), including chemical reactions during the treatment. The proposed study is divided into two steps, fiber treatment and property tests. The first treatment, SF was immersion in the liquid smoke solution for 1, 2, 3, 4, and 5 hours, then dried for 1 hour which then characterized SEM, universal machine testing machine, X-Ray diffractometer (XRD), and Fourier transform infrared spectrometer (FTIR). The acetic acid in liquid smoke reacts with fiber to form fiber-liquid and H2O compounds. The heating process degrades H2O content in fibers and decomposes C and C elements to close together forming strong chemical bonds so that the fiber morphology become rough, porous, grooved and increasing the tensile strength of the fiber. But excessive heating treatment makes fibers more fragile because the H2O elements degrade too low. Dominant percentage of SF crystallization occurred after 4 and 5 hours, 64.7 and 66.9 %, respectively among other durations, a significant increase of tensile strength 50.813 MPa was achieved by 1-hour immersion in liquid smoke. Hence, as alternative to improve the mechanical characteristics of SF, immersion in liquid smoke should be applied. Furthermore, studies of similar treatment on other natural fibers can also be considered in the future.

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Effects of sea water immersion for palm fiber in relation to surface morphology, roughness and bonding between the fiber and sago matrix were observed. Duration of immersion varied in 1, 2, 3 and 4 weeks, and then dried at room temperature for 3 hours continued by oven at 80 °C for 6 hours. SEM and roughness arithmetic tests were applied to see surface morphology, roughness and bonding between fiber and the matrix. Result shows fiber morphology and roughness varies by the duration of immersion. The surface roughness increases as immersion continues along with fiber - matrix bonding improvement. The maximum duration of 4 weeks fiber immersion resulted in the best interlocking of matrix and fibers, as the slits between them disappear.

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High-cycle fatigue tests were carried out on smooth specimens of ultrafine grained (UFG) copper produced by equal channel angular pressing for 12 passes. The growth behavior of a small surface-crack was monitored. A major crack, which led to the final fracture of the specimen, initiated from shear bands (SBs) at an early stage of stressing. Different tendencies of growth behavior occurred depending on the ranges of crack length. To understand the changes in growth rate and fracture surface morphologies, a quantitative model describing a crack growth mechanism were developed considering the reversible plastic zone size at a crack tip. In addition, the crack growth rate of UFG copper was evaluated by applying the small-crack growth raw.