Advanced Materials Research Vols. 726-731

Abstract: This paper presents the structure for a rotary six-bed adsorber that carries out a six-step PSA continuous oxygen generation process with a short cycle time and a low operation pressure ratio. The working principle of a rotary six-bed PSA oxygen generator is introduced and the effects of various operating parameters on PSA performance are experimentally investigated. The results indicate that, the adsorption pressure increases with the reduction of rotating speed and decreases with the lowering of the feed flow rate; with the acceleration of rotating velocity, the oxygen purity of the gas produced first rises and then drops, and it has an optimum rotating velocity; the higher the feed flow rate, the lower the oxygen purity of the product; the ratio of the pressurization angle to the adsorption angle has a remarkable effect on the oxygen purity with the oxygen purity increasing according to the condition of keeping the angle of the feeding ring groove and with the increase in this ratio; and the long-purging time at a low purging-gas flow rate is appropriate for miniature apparatus.

Abstract: Aiming at solving the existing problems of gas treatments on the upper corner presently,poor drainage effect and the high cost of engineering quantity included , gas drag pipe drainage technology and processes on the upper corner is designed.It can make the drainage point matching working face advance speed, realize continuous drainage points in space.And research on the drainage parameters is the foundation of the successful implementation of drag drainage pipe technology.It introduced Brinkman equation, Fick's law of diffusion and gas diffusion translational equations to describe the behavior of gas flow diffusion ,established the migration and diffusion gas flow model at working face ,and the two models are combined in a unified flow field., establishing a coupling model of multi-physics gas flow at the working face.And the model is solved by fluent to determine the optimal parameters of towing pipe drainage.Finally,it makes a practical application and testing results in Changcun coal mine working face N3-8. The results show that gas drag pipe drainage technology is conducing to governing on the accumulation of corner gas,and the gas concentration on the upper corner down to 1%,determining the best the drainage location for distance back plane 2.4m, an inclined direction distance back to the wind tunnel 1.6m, along strike depth to goaf 15m .Taking measures to block the upper corner,which can improve the drainage concentration,and make the concentration of gas on the upper corner down to 0.6%.The application of field basically agrees with the simulation results,so pipe drainage technology has feasibility and good applicability of top corner gas drag

Abstract: Due to the high population density, the environmental accidents would caused the serious social impact and economic loss in China.The chemical parks are the major environmental risk sources. The environmental risk categories are introduced and the corresponding risk prevention measures of chemical industral park to environmental accident are researched in the paper. Moreover, the hazards reduce measures of environmental accidents around the chemical park ,which including the hazardous chemical monitoring, environmental pollution integrated emergency exercise,et al.,are also discussed.

Abstract: During the process of urbanization, impermeable surface areas enlarge and rain runoff and peak discharges grow, rainstorm become more frequent. As more rain water and pollutants mixed with each other, more areas of urban runoff are polluted, causing significant change to aquatic organisms, especially fish, their population and structure. In order to balance the relations between urban development and river eco-environmental protection, avoid reappearance of mega rainstorm disaster like the one on July 21st in Beijing, we suggest protecting and safeguarding the structure and function of urban river ecological system from perspectives of urban planning, eco-environment improvement and integrated management over urban river system.

Abstract: Safety and management of additives used in food have become important issues of public and administrative concern. The most important thing to say is that the use of food additives should be controlled by law. An extensive evaluation on the safety of new additives must be carried out before they are allowed to use in food. This paper discusses the safety evaluation and management system for food additives adopted by the FAO/WHO Codex committees, introduces the internationally standards, guidelines, codes and recommendations established by the Joint FAO/WHO Food Standards Programme with the purpose of protecting the health of consumers and ensuring fair practices in the world food trade. The conclusion is that these international standards and codes have become the global reference for national food control agencies in performing their food additive supervision and management responsibilities on behalf of the consumers.

Abstract: The unstable slope rock is one of the geological disasters of mountains along the transmission lines, which includes the falling style and the slumping type, and the former is very dangerous, and threat to the security of transmission line. By means of a typical example study about the falling dangerous rock mass along the 10kV transmission lines, this paper analyzes qualitatively the basic characteristics, failure mechanism, influencing factors of the dangerous rock, et al., and calculated quantitatively the maximum depth affected by the impact of the dangerous rock to the transmission lines. The paper proposes the response measures of dangerous rocks risk, which is of a certain reference in other similar projects.

Abstract: Sandstorm is a severe weather, interacting with wind and sand, which is more harmful to human health. Sandstorm happens quite frequently in Baicheng city. This paper finds out the causes of sandstorm formation and adopts the form of questionnaire to analyze the sandstorms' harm to the residents health in Baicheng city. And then it comes up with the corresponding countermeasures.

Abstract: To evaluate the male reproductive toxicity of PFOS on mammal animals at cellular level, mouse leydig cells were isolated from healthy mouse testis tissue and cultured in vitro. Adherent cells were treated with a serial concentration of PFOS for 4 more days of culture. Proliferation and DNA damage of the cells were analyzed by CCK assay and SCGE assay respectively. Forty-eight hours of treating with PFOS≧25μg/mL all inhibited the proliferation of the cells (p<0.05). PFOS seemed not to change the time for the cells to reach platform phase. DNA damage was also observed in the groups treated with PFOS dependent on dose and exposure time. The highest DNA damage level was averagely 17 cells per well in 96-well plates, which occurred to 62.5μg/mL group at 72h.

Abstract: Lahar as one of most serious volcanic hazards, threats peoples lives and property securities of volcanic region. Velocity is the most important parameter for lahar hazard assessment and prevention. The calculation result of lahar velocity can provide reference materials for making hazard prevention plan, and make the hazard relief measure of lahar transition from passive to active. Selected the area near the Tianchi as the research region, and divided the research region into forming region, circulation region and accumulation region. In order to establish the calculation model, divided the circulation region and accumulation region into many meshes, which were small enough to meet the calculation accuracy. The calculation time step length was also identified very small as 0.001 min. Calculated the average and peak velocity of lahar, triggered by the assuming medium and small eruption of Tianchi volcano. The longitudinal variation of lahar frontal average and peak velocity was acquired by the numerical simulation result. Although there is some different between the assumption of this research and the actual condition, flow velocity and accumulation situation of lahar are calculated in quantity and extension by numerical simulation, these result has reference value for preventing and reducing lahar disaster.

Abstract: The sea state of the South China Sea is influenced by tropical cyclone obviously. It is important to carry out the long-term prediction and probability analysis of typhoon wind, wave height and wave period for the coastal and offshore engineering. In this paper the measured wind and wave data during typhoon processes from 1964-1989 are used to predict the long-term extreme sea states by using Grey Markov Chain Model. And the joint probability analysis of extreme wave height with concomitant wave period and wind speed is performed by using Multivariate Compound Extreme Distribution model which involves typhoon occurrence frequency and corresponding joint probability distribution of typhoon induced extreme sea environmental events. The proposed model shows that the mean value of typhoon occurring frequency per year plays the significant role in long term prediction of typhoon induced joint return values of extreme sea events.