Bamboo fibers demonstrate enormous potential as the reinforcement phase in composite materials. In this study, in order to find suitable NaOH concentration for bamboo fiber treatment, bamboo fibers were treated with 2 wt.%, 6 wt.% and 10 wt.% NaOH solutions for 12 h, respectively. We determined that 6 wt.% NaOH treated bamboo fibers were optimal for the fabrication of bamboo fiber composites by single fiber tensile test, single fiber pull-out test, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The short length bamboo fibers treated with 6 wt.% NaOH solutions were well dispersed in the epoxy matrix by a new preparation method. The effect of fiber content and fiber length on the mechanical behavior of bamboo fiber reinforced epoxy composites was investigated. The results confirmed that fracture toughness and flexural modulus of the composites monotonically increased with fiber length and content. However, for all samples, composites showed negligible difference on the flexural strength. The fracture surfaces of the composites were observed by SEM, revealing that fiber breakage, matrix cracking, debonding, and fiber pull out were major failure types. In addition, thermogravimetric analysis (TGA) was carried out to investigate the thermal behavior of both bamboo fibers and composites.

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Microscale fluid dynamics has received intensive interest due to the emergence of MicroElectro-Mechanical Systems (MEMS) technology. When the mean free path of the gas is comparable to the channel's characteristic dimension, the continuum assumption is no longer valid and a velocity slip may occur at the duct walls. Non-circular cross sections are common channel shapes that can be produced by microfabrication. The non-circular microchannels have extensive practical applications in MEMS. Slip flow in non-circular microchannels has been examined and a simple model is proposed to predict the friction factor and Reynolds product fRe for slip flow in most non-circular microchannels. Through the selection of a characteristic length scale, the square root of crosssectional area, the effect of duct shape has been minimized. The developed model has an accuracy of 10% for most common duct shapes. The developed model may be used to predict mass flow rate and pressure distribution of slip flow in non-circular microchannels. hydraulic diameter = 4A/P E(e) complete elliptical integral of the second kind e eccentricity ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi Keywords

This study was conducted to investigate the effects of dietary protease on growth performance, feed utilization, whole-body proximate composition, nutrient digestibility, intestinal and hepatopancreas structure of juvenile Gibel carp, Carassius auratus gibelio (mean weight 8.08 ± 0.18 g). Six diets were prepared, including a positive control diet (dietary protein 350 g/kg, PC), one negative control diet (dietary protein 33 g/ kg, NC) and four protease supplementations diets, which were 75, 150, 300 and 600 mg/kg protease NC diet. After 12 weeks of diet feeding in indoor recycle aquarium tanks, no significant difference (p > .05) was found on growth performance between fish fed diet with 75-600 mg/kg protease and the PC group. Compared with the fish fed the NC diet, the specific growth rate of fish fed 300 mg/kg protease increased significantly (p < .05), as well as protein efficiency ratios (p < .05), while feed conversion was the opposite (p < .05). The nutrient digestibility of crude protein and lipid was higher (p < .05) in fish fed 150 mg/kg protease diet than the PC diet. Wholebody proximate composition of fish was not affected (p > .05) by the dietary treatment. Serum alkaline phosphatase and albumin were significantly affected by dietary protease (p < .05), while the content of total protein, glucose, triglyceride, total cholesterol, aspartate aminotransferase and alanine aminotransferase activities in serum was not affected (p > .05). Foregut muscular thickness was thinner (p < .05), when the fish fed diets supplementation of protease in 150 or 600 mg/kg diet than the NC diet.Protease activities in hepatopancreas and foregut were higher (p < .05), in the fish fed 150 or 300 mg/kg protease diet than the fish fed the PC diet, but those in the mid-and hindgut were not significantly affected (p > .05) by the dietary treatments. Based on the regression analysis of weight gain rate, the optimal dietary inclusion level of protease was 400 mg/kg in the diet for juvenile Carassius auratus gibelio. K E Y W O R D SCarassius auratus gibelio, feed utilization, growth performance, intestinal and hepatopancreas structure, nutrient apparent digestibility, protease

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Microscale fluid dynamics has received intensive interest due to the emergence of micro-electro-mechanical systems (MEMS) technology. When the mean free path of the gas is comparable to the channel’s characteristic dimension, the continuum assumption is no longer valid and a velocity slip may occur at the duct walls. Noncircular cross sections are common channel shapes that can be produced by microfabrication. The noncircular microchannels have extensive practical applications in MEMS. The paper deals with issues of hydrodynamic flow development. Slip flow in the entrance of circular and parallel plate microchannels is first considered by solving a linearized momentum equation. It is found that slip flow is less sensitive to analytical linearized approximations than continuum flow and the linearization method is an accurate approximation for slip flow. Also, it is found that the entrance friction factor Reynolds product is of finite value and dependent on the Kn and tangential momentum accommodation coefficient but independent of the cross-sectional geometry. Slip flow and continuum flow in the hydrodynamic entrance of noncircular microchannels has been examined and a model is proposed to predict the friction factor and Reynolds product f Re for developing slip flow and continuum flow in most noncircular microchannels. It is shown that the complete problem may be easily analyzed by combining the asymptotic results for short and long ducts. Through the selection of a characteristic length scale, the square root of cross-sectional area, the effect of duct shape has been minimized. The proposed model has an approximate accuracy of 10% for most common duct shapes.

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