Advanced Materials Research Vol. 508

Abstract: This paper introduced an optimum design method of sensor array suitable for electrical capacitance tomography (ECT) based on high AC excitation voltage. The sensor parameters of electrode span and length were optimized in turn, and a sensor model for testing was fabricated according to optimal objects. The image reconstruction experimental resultants of grain distribution indicated that high quality images could be reconstructed by the sensor model. This proved the optimal design method of ECT sensor given in this paper was feasible and the parameters were also credible.

Abstract: A new design method of human-body ADL(activity of daily living) real-time monitoring based on Internet of things is proposed, which is able to detect body posture of elderly persons and biological signal at rehabilitation centers or nursing homes. With this way patients body state information can be transmitted to doctors or their family through mobile phone or PC. Human body wear sensor nodes which consist of wearable sensors and data transmission module to detect posture or bodys activity and transmit data to base station which is distributed in elder persons daily living environments. It's possible that increased number of nodes in each base station may cause network congestion. Real-time performance in this data transmission system is important to protect elder people when abnormal activities occur. A new data processing algorithm, which can reduce the transmission cycle time effectively and improve the real-time and robustness performance, based on Bayesian network is presented here. Finally, experimental results indicate that Bayesian network parameters training method is effective and real-time performance is improved.

Abstract: Optimized capacitance sensor with helical shaped surface plates has an obvious advantage of smaller homogeneous error which helps to make the measurement result insensitive to phase distribution and flow changes. The angle of rotation is one of the most important structural parameters to the sensor optimization design. The effect of rotation angle of the helical surface plate to the performance of the sensor with different diameters was studied in this paper. Results showed that the best rotation angle of the helical surface plate was different for different sizes of sensor. 360 degree rotation angle is the best to obtain the smallest homogeneous error when the diameter is greater than 32mm, however, 180 degree is the best when the pipe diameter is less than 31mm, ,

Abstract: In order to acquire more feature information in captured vein image with high-quality, an image quality assessment algorithm for palm-dorsa vein is presented based on multi-feature fusion. According to the statistical and structure properties of image, we can acquire the good vein image by adjusting near-infrared LED light exposure duty cycle combined with computing the four characteristic parameters of gray variance, information entropy, cross point and area of effect and then fusing those according to weights. In the end, an experimental case is given and the assessment results prove that this algorithm is efficient.

Abstract: Risk management is specific to the organization and its external and internal context. In this paper risk management and some concepts focusing specifically on such plants for dusty, granular and combustible products were introduced. Some examples were presented here for practical uses, which can be applied in dusty and complicated surroundings.

Abstract: By using high-voltage breakdown, low-voltage continued arc principle in the 20L ball-type dust explosive device, 8000J level of spark discharge energy was successfully achieved, measuring results of chemical ignition were compared with spark ignition. Using oscillometric method, integral measurement of spark energy was done, and the results provide effective guidance for related experiments.

Abstract: Accurate measurement of dust resistivity is important practically for electrostatic prevention and design of electrostatic precipitators. The test result of dust resistivity depends on the standard used. There are three standards widely used for determination of dust resistivity: IEC 1241-2-2, BS 5958-1 and ASME PTC28 4.05. Experimental devices are designed and constructed according to these standards. The schematics of test principles and circuits of different standards are introduced. Experimental results show that dust resistivity values determined by different standards are quite different, and in some cases the difference is even in 1~2 orders of magnitude. The test results according to IEC standard are the highest, while the results using ASME standard are the lowest. The methods given by IEC standard and BS standard are normally used in electrostatic prevention, while method given by ASME standard is applied to the design of electrostatic precipitators. It is necessary to choose the appropriate standard according to the application of dust resistivity.

Abstract: Maize starch is abundant in quantity in China. The hazard from dust explosion of maize starch was very great. Number simulation is a good way to predict the consequent of dust explosion, but the known of reaction kinetics of hazardous materials is necessary. The objective of this research was to determine the reaction kinetics of maize starch using thermo-gravimetric analyses. Thermo-gravimetric analyses of maize starch were performed at heating rates of 5, 10, and 15 min^-1 in an air atmospheres. The weight losses of maize starch in an air atmosphere were found to occur in three stages. The parameters of the reaction kinetics were obtained in Stage and .

Abstract: In order to understand the whole process of dust explosions of magnesium powders, a model to describe the evolution of the pressure in the 20L sphere was proposed. This model took into account the nitrification and oxidation of magnesium powder during the explosion. Moreover, the thermal conduction through the wall of the sphere was also taken into account in this model. The model was found to match the experimental data closely.

Abstract: Toner powder is an important constituent of a toner cartridge for a laser printer and has potential hazards of combustion and explosion because of its physicochemical characteristics. In this paper, physicochemical, combustible and explosive characteristics of hpQ2612A toner are investigated experimentally. The mean size of the toner powder is about 2.45 μm and it has several organic groups such as carboxyl group, hydroxyl group and carbonyl group which make the toner dust much easier to combust. The TG-DSC curves show that the toner dust is combustible and the combustion process starts at about 368 . The dust explosion characteristics of the toner dust were, respectively: MIE=5~30 mJ, P_max=0.74 MPa, (dP/dt)_max=100.5 MPa/s, LEL=40~50 g/m³. These results reveal that the toner powder is a dangerous industry dust and has the possibility to make tragedy such as combustion or even explosion.