Applied Mechanics and Materials Vols. 121-126

Abstract: Red Yeast Rice and monascus pigments are main monascus products in China. Monascus pigments are used as natural food colorants. Red Yeast Rice can be used as material of monascus pigments or as nutrition supplement. The citrinin contamination in monascus products restricts the health development of monascus fermentation relative companies. We collected and investigated 20 monascus products from different companies in China. The quality evaluation was measured from three aspects as follow: pigments color values, monacolin k content, and contamination of citrinin. The results showed that 50% monascus pigments samples are superior in quality, which have higher color values without the citrinin contamination. Most of Red Yeast Rice samples absent of monacolin k. Only two Red Yeast Rice samples contain monacolin k, which accompanied with citrinin contamination.

Abstract: A new D/SiO2 CMG tool for Al2O3 ceramic process was developed by adding some diamond abrasive into SiO2 CMG tool. The solid state reaction between the CMG tool and Al2O3 ceramic played a key role for achieving ultra-precision, high efficiency and low damage.Three kinds of formulations for the D/SiO2 tool were tested and evaluated. The material removal rate(MRR) of Al2O3 ceramic mainly depended on the content of diamond abrasive. In contrast with the corresponding SiO2 tool,the D/ SiO2 tool, which had minimal content of diamond abrasive,could achieve a minimal Ra and better MRR. The enhanced mechanical removal action made the MRR improve nearly twice times, and the process surface roughness of Al2O3 ceramic specimen using the D/ SiO2 tool kept almost same value as using the SiO2 tool without surface damage. Thus the D/ SiO2 tool is more suitable for process of Al2O3 ceramic workpieces.

Abstract: An experimental device capable of producing uniform metal droplet stream and electric charging and deflecting has been developed. Uniform spherical powder of 180μm in diameter was obtained after cooling and solidification. Numerical models of heat transfer and solidification of droplets were established. The thermal history including solid fraction of droplets in uniform droplet spray process were calculated. Under the common processing conditions, the cooling rate of a droplet of 180μm diameter is of the order of 103−104°C/s. To obtain homogeneous and dense preforms, the substrate should be positioned at a distance of 1.1-1.3m from the nozzle.

Abstract: According to the microstructures of small grain shellproof ceramic composite, the effective self-consistent method is used to determine the effective stress field of the shellproof ceramic composite. Based on the effective stress field and fracture feature of small grain shellproof ceramic composite, considering the mechanism of growth and coalescence of microvoids, crack nucleation model of the shellproof ceramic composite is built. Under the effect of shearing stress, dislocations slip along slip plane and pile up in matrix grain boundary. Owing to the stress concentration before leading dislocation, there is a stress field around the stress concentration. Letting the maximum tensile stress equal to the theoretic fracture strength of composite matrix, the ultimate stress of small grain shellproof ceramic composite is obtained.

Abstract: Thermal error in machine tools is one of the most significant causes of machining errors. This paper presents a new modeling method for machine tool error. Minimal-resource allocating networks (M-RAN) are used to establish the relationships between the temperature variables and thermal errors. Pt-100 thermal resistances and eddy current sensors are used to measure the temperature variables and the thermal errors respectively. A machining center is used to experiment. The test results show that method with minimal-resource allocating networks can predict the thermal errors of the machine accurately.

Abstract: Three-body abrasive wear behavior of basalt–epoxy (B–E) and glass–epoxy (G–E) composites have been investigated using Dry sand rubber wheel abrasion resistance for various abrading distance, viz., 150, 300, 450 and 600m and different loads(22N and 32N) at 200 rpm. The weight loss and specific wear rate as a function of load and abrading distance were determined. The weight loss increases with increasing load and also with abrading distance while the specific wear rate decreases with increase in abrading distance and increases with the load. Better abrasion wear resistance was observed in B-E composite compared to G–E composite. Scanning Electron Microscope (SEM) is used to examine the abraded composite specimens and revealed that the more damage occur to glass fiber compared to basalt fiber. Also good interfacial adhesion was observed between epoxy and basalt fiber which leads to good abrasive wear resistance.

Abstract: A method based on laminated plate theory is presented for estimating three-dimensional effective elastic moduli of multi-directional hybrid filament-wound composite cylindrical shell with lining. The method introduces a factor of hybrid effects. The effective elastic moduli of glass/epoxy fiber-wound tube with lining and glass/carbon/epoxy hybrid fiber-wound tube with lining are predicted by present method respectively. It is shown that the method is simple and accurate.

Abstract: In this paper, the topology optimization of nonlinear Kirchhoff plate was studied by using meshless Reproducing Kernel Particle Method (RKPM). The relative densities of nodes were chosen as design variables to eliminate the checkerboard pattern, and the visibility criterion method was used to dispose the discontinuity of RKPM approximation function in the nonlinear Kirchhoff plate. The topology optimization model of nonlinear Kirchhoff plate based on RKPM was developed, and the topology optimization procedure was given in detail. Finally, all the Matlab programs were written, and one numerical example shows the advantage of the present method.

Abstract: A relation to determine the transverse stress in terms of in-plane stresses for elastic-plastic plane strain problems in a power-law hardening material is presented. The results might prove useful in the elastic-plastic analyses of plane strain problems

Abstract: The objective of this study was to assess the potential of applying enhanced landfarming system on the treatment of diesel-oil contaminated soils. Laboratory reactors were conducted to determine the optimal operational conditions of the modified landfarming. Except of frequent soil tilling for air replacement, different additive was added in each reactor enhance the removal efficiency of total petroleum hydrocarbon (TPH). The additives used in this study included kitchen waste compost, petroleum-hydrocarbon (PH) degrading bacteria, rice husks, and activated sludge. PH-degrading bacteria were isolated from PH contaminated soils and activated sludge was collected from a wastewater treatment plant containing PH in the influent. PH-degrading bacteria and sludge were added to increase the microbial population and diversity. Rice husk was used as the bulking agent (soil to bulking agent volume ratio = 3:1) to increase the soil permeability. The compost (soil to compost volume ratio = 3:1) was used as organic amendment to increase both the microbial population and soil permeability. Results indicate that the highest first-order TPH decay rate and removal ratio were approximately 0.1 day-1 and 92.4%, respectively, observed in reactor containing compost. In the compost reactor, TPH dropped from 5,900 to 450 mg/kg and total viable bacterial counts increased from 9.4×105 to 7.2×108 cfu/g of soil within 25 days of incubation. This indicates that the kitchen waste compost contained high microbial population and organic content, which could cause the rapid bacterial growth and enhance the TPH degradation. The TPH removal ratios for sludge, PH-degrading bacteria, rice husks, and control reactors were 86.9, 83.1, 79.7, and 54%, respectively. This indicates that the soil tilling played an important role in the landfarming system, and significant amount of TPH removal was due to the volatilization mechanism. Adding sludge or PH-degrading bacteria could cause the increase in both the total microbial population and specific PH-degrading microbial consortia, which caused the increased TPH removal efficiency.