The elastic moduli and fatigue properties of canine trabecular bone tissue

The elastic modulus and fatigue properties of canine and human trabecular bone tissues (single trabeculae) were experimentally determined on a microstructural level using four-point bending cyclic test, and they were compared based on microstructural characteristics and mineral density. The results showed that canine trabecular bone tissue had significantly lower modulus and lower fatigue strength than human tissue. The observed microstructural differences between the two tissues may be more responsible for the differences, although the lower mineral density in canine tissue might also have contributed to the lower modulus and fatigue strength.     

Error concealment using affine transform for H.263 coded videotransmissions

A new error concealment method is proposed that uses motion estimation to consider actual motions, such as rotation, magnification, reduction, and parallel motion, in moving pictures. Since many videos include a variety of complex three-dimensional motions, the proposed method uses an affine transform to estimate the motion of lost data more accurately, thereby producing a higher peak signal-to-noise ratio value and better subjective video quality     

Composition Dependence of the Electrical Conductivity of ZnO(n)–CuO(p) Ceramic Composite

Electrical properties of semiconducting ZnO( n )-CuO( p ) ceramic composites with varying composition were investigated. The electrical conductivity increased with increasing CuO volume fraction between 1 to 95 mol%. Impedance response showed three semicircles, indicating three resistive elements contributing to the total resistance of the composite. A new model based on the equivalent circuits was developed to explain the contribution of grain boundaries to the resistance of the composite. The change of electrical conductivity was explained by the probability change of two equivalent circuits.     

Experimental studies on the instabilities of viscous fingering in a Hele-Shaw cell

When air is injected into silicone oil contained in a horizontal Hele-Shaw cell, a single air bubble forms and grows showing various interesting phenomena. In this study the effects of the bubble front velocity, air injection velocity at a nozzle, fluid properties and cell depth on the stability of the growing bubble were investigated experimentally. By using the modified capillary number involving the aspect ratio, we obtained the onset conditions of the unstable bubble. Also, the bubble width was analyzed both quantitatively and qualitatively. Before the bubble experiences splitting, the bubble front velocity is almost proportional to the air injection velocity. Therefore the latter velocity may be used in a practical sense.     

Effect of water drying conditions on the surface property and morphology of waterborne UV-curable coatings for engineered flooring

UV-curable coatings are widely used on wooden materials such as flooring and furniture, because they have excellent properties, including high hardness, gloss, mar and chemical resistance, and are also environmental friendly, containing no solvents. Recently, waterborne UV-curable coatings have been studied as a viable alternative, since solvents are added to spray applications to lower viscosity. We investigated the effects of water drying conditions on the surface properties and morphology of waterborne UV-curable coatings at the flash-off step. Temperature conditions studied were 22 °C, 50 °C, and 80 °C, with various drying times. We evaluated surface properties such as pendulum hardness, pencil hardness, and adhesion strength. Also observed was surface morphology, comparing surface properties using optical microscopy after drying and UV-curing. Insufficient drying caused cracking, peeling and blistering at the surface of a cured coating. Sufficient drying was very important for the best application and ideal surface morphology of waterborne UV-curable coatings.     

Control of chaotic dynamical systems using radial basis function network approximators

This paper presents a general control method based on radial basis function networks (RBFNs) for chaotic dynamical systems. For many chaotic systems that can be decomposed into a sum of a linear and a nonlinear part, under some mild conditions the RBFN can be used to well approximate the nonlinear part of the system dynamics. The resulting system is then dominated by the linear part, with some small or weak residual nonlinearities due to the RBFN approximation errors. Thus, a simple linear state-feedback controller can be devised, to drive the system response to a desirable set-point. In addition to some theoretical analysis, computer simulations on two representative continuous-time chaotic systems (the Duffing and the Lorenz systems) are presented to demonstrate the effectiveness of the proposed method.     

COMPARISON OF PROBE METHODS FOR MEASUREMENT OF BUBBLE PROPERTIES

Direct quantitative comparisons of four different probe methods were performed for determination of local gas holdup, vertical bubble length, bubble rising velocity, and bubble frequency. The methods include vertically projecting electroresistivity, horizontally projecting electroresistivity, U-shape light reflection, and light transmission. The measured bubble properties strongly depended on the size and configuration of the probe tips. The light transmission probe developed in this work can be used to determine the bubble properties effectively. In order to minimize interferences with bubble flow, the size of probe tip should be small as possible and its configuration must be vertically projecting.     

Nucleation and growth of aluminium oxide on silicon in the CVD process

Films of aluminium oxide have been formed on single crystal silicon substrates using AlCl₃-CO₂-H₂ gas mixtures in a cold-walled chemical vapour deposition (CVD) reactor. The nucleation and subsequent growth of the deposit have been observed under the varying process parameters. It is found that the nucleation and growth of the Al₂O₃ are dependent on the H₂O flux and H₂O supersaturation. An activation energy of 34.8 Kcal mol^–1 is obtained for the growth rate indicating that the CVD of Al₂O₃ on silicon is a thermally activated process and limited by surface reaction. Scanning electron micrographs (SEM) show that the deposited films are amorphous at low temperature, 850° C, but change to fine grained polycrystalline structure at high temperature, 1000° C.     

Effect of bipolar plate materials on the stress distribution and interfacial contact resistance in PEM fuel cell

In polymer electrolyte fuel cell (PEFC) system, ideal structural integrity design takes into account the end-to-end load transfer mechanism. Hence, structural durability of cell is dependent of individual layers response to the external clamp loading. Since failure modes of each layer differ from another, multidisciplinary approach is needed to innovative designs. Bipolar plate (BPP) of PEFC is multi-functional layer that has a significant potential for research to avoid its structural failure as well as neighboring layers. To this end, present work investigates the effect of BPP materials on the stress transfer as well as distribution in cell layers based on theoretical investigation for clamping load. Gas-diffusion layer (GDL) / BPP interface has drawn considerable interest among researchers due to its susceptibility for damage failure and other related losses. Hence, investigating the interfacial behavior and relating this to the electrical contact resistance is the key feature in proposed investigation.     

Antioxidant activities from the aerial parts of Platycodon grandiflorum

In order to obtain basic data necessary for the utilisation of aerial parts from Platycodon grandiflorum as a functional substance in Korea, the antioxidant activities of solvent fractions from the ethanol extract of P. grandiflorum aerial parts were examined. The butanol fraction from P. grandiflorum showed the most potent antioxidant activities in each assay, showing 91.31% in the DPPH radical scavenging method, 99.62% in the ABTS radical scavenging method, 7.84% in the reducing power method, and 1.29% in the FRAP method at a concentration of 10 mg/ml. The DPPH, ABTS, reducing power, and FRAP assay indicated that the butanol fraction of aerial parts of P. grandiflorum was the most potent radical-scavengers and reducing agents compared to the other two extracts. Therefore, our study verified that the butanol fraction has strong antioxidant activities which are correlated with its high level of phenolics, particularly luteolin-7-O-glucoside and apigenin-7-O-glucoside. This extract of P. grandiflorum aerial parts can be utilised as an effective and safe source of functional food materials such as natural antioxidants.