Advanced Materials Research Vol. 705

Abstract: Coal Bottom Ash (CBA) is a by-product from the generation of electricity using pulverized coal; Tanjung Bin power plant in Malaysia is a coal-based power plant that generates tonnes of bottom ash daily without known economic value that ends up in the ash pond. Due to the problems associated with the disposal ash pond in terms of cost and environmental impact, attention has now been focused on how best to utilize this waste. This paper present the recent development achieved on the utilization of bottom ash from Tanjung Bin power plant Malaysia in concrete development; physical and chemical properties, workability and fresh concrete properties as well as the strength development of Tanjung Bin bottom ash.

Abstract: In order to develop high functionality of shape memory materials, the shape memory composites combined with TiNi wire and shape memory epoxy were prepared, and the mechanical and thermomechanical properties were studied. The results showed the addition of TiNi wire increased the Young modulus and breaking strength both at room temperature and at elevated temperature. The composites maintained the rates of shape fixity and shape recovery close to 100%. The maximum recovery stress increased with increasing TiNi wire volume fraction, and obtained almost 3 times of the matrix by adding 1vol% TiNi wire.

Abstract: The two-dimensional viscoelastic solid is considered in symplectic system. The general solutions of the governing equations include zero eigensolutions and non-zero eigensolutions. Zero eigensolutions can describe all the Saint-Venant problems, and non-zero ones are local effect solutions. Via this analytical approach, the final solution of the problem can be expressed by the linear combination of the general eigensoutions. In this paper, the local effects are described by employing this analytical approach.

Abstract: The paper deals with metal flow velocity in an intake port in the process of die casting. In the theoretical part the author defines theoretical knowledge from the field of the mold cavity filling regime and the velocity of pressing the melt into the mold cavity. The practical part focuses on the impact of metal flow velocity in an intake port and the filling regime of the pressure foundry mold cavity, related to the former, on the homogeneity of the casting.

Abstract: For parts made of plastics, injection molding is a common manufacturing process. Warpage and residual stress induced during the injection molding process have very important influences on the mechanical performance of injection products. In this paper, an integrative analysis of the injection molding process and mechanical performance of plastic parts is proposed. This integrative approach incorporates the effects of the manufacturing process in the mechanical simulation: (a) firstly, the finite element package MoldFlow is used to simulate the injection molding process and obtain the warpage and residual stress results. (b) Then the finite element model of plastic part including the process induced warpage and residual stress is established. Explicit dynamic finite element program LS-DYNA is used to simulate the mechanical behaviors of the molded part. Based on the integrative analysis, the influences of injection molding process parameters on mechanical behavior of a PC windshield against impact loading are studied.

Abstract: The aim of this study was to investigate the effect of natural herb material Galla Chinensis extraction (GCE) on the wear resistance of dentine in vitro. Forty sound bovine dentine blocks were prepared and randomly divided into two groups. The samples were first treated with 4000 ppm aqueous solution of Galla chinensis and distilled deionized water (DDW) was used as a control. Then the samples were subjected to 5,000 cycles of attrition bathed under artificial saliva with 150 N loads. Wear measurement, scanning electron microscopy (SEM) examination and energy-dispersive X-ray spectrometry (EDX) analysis were utilized to evaluate the effects of GCE on the wear resistance. The depth of the wear scar of DDW-treated surface (mean = 32.5 μm, SD = 11.8 μm) was significantly greater than that of GCE-treated surface (mean = 26.4 μm, SD = 13.9 μm) (p < 0.05). Furthermore, the SEM images showed severe wear on the DDW specimens and less wear on the GCE-treated samples. Finally, from EDX data, GEC group had higher percentage of Ca and P than the control. In conclusion, our study suggested that Galla chinensis could enhance wear resistance of dentine.

Abstract: The relative analysis of characteristics of time series of damage number and damage cluster number was made with a probabilistic cellular automaton on the basis of simulation of damage cluster ensemble evolution. There was demonstrated, that the transfer of the time series damage number autocorrelation to negative value conforms the transfer of cluster ensemble evolution to the stage of coalescence. The qualitative consent between the behaviour of autocorrelation observed by experiment with measurement phonon and electromagnetic emitting in loaded materials was assigned.

Abstract: Stainless steel S304 was used as experimental subjects, the influences of current density on the passive film morphology, thickness and removal quantity were studied by quantitative experiments. The effect of electrolyte concentration on polarization curve characteristics of stainless steel S304 was qualitatively analyzed. The results show that the passive film morphologies dandify with increasing current density; passive film thickness increases with increasing current density; the change tendency of removal with the current density is consistent with the theoretical formula.

Abstract: The pulse electrochemical finishing (PECF) of GCr15 bearing steel was studied. The effect of the main processing parameters, such as electrolyte concentration, inter-electrode gap, current density, pulse parameters, and processing temperature, on the processed surface quality was discussed. The results indicate that PECF has a good effect on GCr15 bearing steel and has a good application prospect on the finishing of bearing raceways.

Abstract: Failure of cylindrical vessels can be caused by stress singularity at pitting corrosion induced cracks. Literature suggests that most of research focuses on how to determine stress intensity factors for surface cracks with low aspect ratios, i.e.,a/c1.0. Situation may well arise where the aspect ratio of cracks is larger than one. This paper attempts to propose a weight function method to determine stress intensity factors for high aspect ratio semi-elliptical cracks in cylindrical vessels. The weight functions are derived based on three dimensional finite element analysis. The proposed weight function method is verified numerically. It is found that the higher the aspect ratio of cracks the larger the stress intensity factors, and that the aspect ratio of cracks may alter the failure mode of cylindrical vessels.