Key Engineering Materials Vols. 480-481

Abstract: In this study, effect of the initial substrate concentrations of the Belouzov-Zhabotinsky (BZ) on a period and transmittance self-oscillating behavior for a polymer chain were investigated under the constant temperature condition (T = 20 °C). The polymer chain was composed of a non-thermoresponsive poly-vinylpyrrolidone (PVP) main-chain covalently-bonded to the 10 wt% ruthenium catalyst (Ru(bpy)3) of the BZ reaction. The transmittance self-oscillation originates from the different solubility of the Ru catalyst moiety in the reduced and oxidized state. The waveform and period of the non-thermoresponsive polymer chain was significantly affected by the initial concentration of the BZ substrates. Moreover, as the concentration of the Ru catalyst increased due to the increase in the polymer concentration, the period hardly changed because of the high solution viscosity.

Abstract: Synthetic method is studied on assessing scale and surface machined effect on fatigue lives of China railway grade B cast steel wheel. Three kinds of specimens are applied for revealing the non-linear effect with scale kinetics at a least of cost. And 8 to 9 samples are applied for each kind of specimen to reveal the random fatigue behaviour. Assessing work is carried out on a phase of fatigue lives with scale kinetics at a specified strength. Results reveal that fatigue cracks were initiated from the specimen surface having a bigger site and the fatigue damage process companied with less plastic deformation than the material specimens. Random effects on fatigue lives and effect factors are constructed for measuring effects. Statistical character of the test data has been well described.

Abstract: In this study, the influence of the temperature on the transmittance self-oscillation of a non-thermoresponsive polymer chain was investigated. The polymer chain was composed of a biocompatible and non-thermoresponsive poly-vinylpyrrolidone (PVP) main-chain covalently-bonded to the 10 wt% ruthenium catalyst moiety (Ru(bpy)3) of the BZ reaction. As a result, the amplitude of the transmittance self-oscillation slightly decreased with the increase in the temperature. The period of the transmittance self-oscillation decreased with increasing the temperature in accordance with the Arrenius equation. Therefore, the period of the self-oscillation can be controlled by the selection of the temperature.

Abstract: Fracture surface observations and statistical deriving are applied experimentally for the present investigation on random fatigue cracking thresholds of China grade B cast steel wheel. Results reveal that: the crack grows with relative regular initial tip companied fabric like stripes along the growth direction but few of fatigue striations and then, cleavage flowers appearing on the district of transient fracture with few of dimples. This indicates that sharp notched structures may be subjected to a little plastic dissipation process. In the same time, non-linear statistical modeling is constructed for describing the random crack growth and then, random fatigue cracking thresholds are measured at specified growth rate. The measurements hold a same growth rate which can not be obtained directly from test results.

Abstract: Fracture surface observations and statistical deriving are applied for investigating the random critical fracture toughness values of China grade B cast steel wheel. Results reveal that: the crack grows to show fabric like stripes along the growth direction with few of dimples. Cleavage flowers appear under higher magnification. Cracked structural damage process is verified with few of plastic dissipation. At the same time, code based evaluated results indicate that significant scatter exists for the toughness values. Lognormal modeling is constructed appropriately with a comprehensive statistical comparison method. It is verified that random characters and quantitative measurements have been well depicted for the present critical fracture toughness values.

Abstract: Fracture surface observations and statistical deriving are applied for the present investigation on the random fatigue crack growth rates of China grade B cast steel wheel. Results reveal that: the crack grows with relative regular initial tip companied fabric like stripes along the growth direction but few of fatigue striations, and then, cleavage flowers appearing on the district of transient fracture with few of dimples. It indicates that sharp notched structural crack behaviour acts as a few of plastic dissipation process. Non-linear statistical modeling covering entire three pieces of fatigue crack growth is constructed for describing the random crack growth rates. Scattered randomness of the growth rates has been well characterized.

Abstract: Waveband selection of near-infrared (NIR) spectroscopy analysis of wastewater chemical oxygen demand (COD) by moving window partial least squares (MWPLS) method with changeable size, the optimization of PLS factor was combined with MWPLS method. According to the prediction effect, the optimal model was selected, and the corresponding waveband, number of adopted wavelengths, PLS factor, RMSEP, RP were 820-850nm, 16, 13, 25.5 mg/L, and 0.968 respectively, which was obviously superior to the optimal PLS model on the whole spectral collecting region. The result shows that the MWPLS method can improve the model prediction effect, reduce model complexity, and provide valuable reference for designing special NIR spectrometer.

Abstract: Ontology integration is to eliminate ontology heterogeneous, so as to achieve the highest level of semantic communication and semantic integration, and finally achieve knowledge reuse and interoperability. The paper describes the four main methods and the five main tools for ontology integration, and then compares and analyses them.

Abstract: For investigating the effect of wet milling time on thermoelectric properties, bulk CoSb3 was prepared via wet milling and sintering. The phases of samples were analyzed by X-ray diffraction and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, the major phases of the samples sintered from the powders wet-milled 2 and 6 hours are CoSb3 while the samples sintered from powders wet-milled 12 and 20 hours have more impurity phases under the experimental conditions in this work. The electric resistivities of the samples sintered from the powders wet-milled 2 and 6 hours increase with rising temperature, which show the characteristic of typical semiconductor electricity and P-type conducting due to the positive Seebeck coefficients. However, the samples sintered from powders wet-milled 12 and 20 hours show N-type conducting due to their negative Seebeck coefficients. The ZT values of the samples sintered from the powders wet-milled 2 and 6 hours are relatively higher than other samples, which increases with the temperature rising at 100~400 °C, the highest value is 0.078.

Abstract: At present, the use of scanning electron microscope (SEM) is becoming more and more extensive in the field of materials examination. But it may be restricted since most of the SEM sample stages just have single function and the existing multifunctional SEM sample stages are poor practicability. In this schematic design, two multifunctional SEM sample stages are designed by means of reforming the construction of SEM sample stage. Specifically, the aims of conducting structural dynamic observation in the process of stretching or compressing samples and detecting flexible long samples are achieved by installing different mechanical clamping devices on the SEM sample stage base. Furthermore, the two multifunctional SEM sample stages have advantages of relatively simple construction, low lost and strong practicability.