Prevention of steel corrosion in concrete exposed to seawater with submerged sacrificial anodes

This paper presents the results of a study of the effectiveness of submerged sacrificial anodes in preventing the onset of pitting corrosion in the emerged part of marine piles. Experimental tests were carried out on reinforced concrete columns with steel embedded both in chloride free concrete and chloride contaminated concrete in order to compare the effects of sacrificial anodes on passive steel and on corroding steel. Results have shown, at least under the present testing conditions, that sacrificial anodes may be more effective in preventing corrosion initiation (i.e. in providing cathodic prevention) than in controlling ongoing pitting corrosion (i.e. in guaranteeing cathodic protection). Monitoring criteria for this type of prevention are also discussed.     

中子探测用闪烁体的研究进展

简要综述了中子探测的相关理论和中子探测对于材料的性能要求.同时简要论述了国际上正在应用的中子探测用闪烁材料的性能特点.展望了新型中子探测材料的发展态势和几种具有潜在应用价值的中子探测材料.     

Neutron energy dependence of delayed neutron yields and its assessments

Incident neutron energy dependence of delayed neutron yields of uranium and plutonium isotopes is investigated. A summation calculation of decay and fission yield data is employed, and the energy dependence of the latter part is considered in a phenomenological way. Our calculation systematically reproduces the energy dependence of delayed neutron yields by introducing an energy dependence of the most probable charge and the odd–even e?ect. The calculated fission yields are assessed by comparison with JENDL/FPY-2011, delayed neutron activities, and decay heats. Although the fission yields in this work are optimized to delayed neutron yields, the calculated decay heats are in good agreement with the experimental data. Comparison of the fission yields calculated in this work and JENDL/FPY-2011 gave an important insight for the evaluation of the next Japanese evaluated nuclear data library (JENDL) .     

RESEARCH ON MATHEMATICAL SIMULATION OF RESIDUAL CHLORINE DECAY AND OPTIMIZATION OF CHLORINATION ALLOCATION OF URBAN WATER DISTRIBUTION SYSTEM

The concentration of Residual Chlorine (RC) frequently violates the standard in situations of urban water distribution system with large water supply area and long time of distribution. If chlorine dosage increases within water treatment plant, although RC in distribution system could meet water quality standard, Disinfection By-Products (DBPs) such as hydrocarbon halide rises. In the paper, a mathematical model of chlorine allocation optimization was presented based on reaction kinetics mechanism and optimization theory to solve the problem. The model includes the objective function of minimizing annual operation cost and constraints of RC standard and rational chlorination station distribution, and solving by 0-1 Integer Programming (IP). The model had been applied to a real water distribution system. The simulation results of the model showed that adding chlorine in‘ water distribution system remarkably improved water quality and reduced the operation cost by 49.3% per year less than chlorine dosed only in water treatment plant to meet RC standard. The results prove adding chlorine in water distribution system based on the model can bring both technological and economic advancement.     

利用真空衰减法测试预包装食品的密封性

目的 预包装食品的密封性关系到食品质量与安全。本文针对预包装食品目前普遍采用水检气泡法时灵敏度不足的问题,采用真空衰减法检测食品包装的密封性。方法 分别利用2种不同检测技术对市面上55款预包装食品样品进行密封性检测,并根据包装类型、封合方式、包装规格等不同分类方式将测试数据进行综合比较分析。结果 水检气泡法测试成本低,可明显地指示出泄漏位置,但方法灵敏度较低,且无法准确定量;真空衰减法可在不破坏原有包装的情况下,大幅度提高检测灵敏度,并得到定量数据,但无法准确指示泄漏点位。结论 真空衰减法可以作为水检气泡法的有效补充方法在实际工作中使用。     

具有点反馈的Rayleigh梁的能量衰减估计

本文研究在某种边界条件下具有点反馈的Rayleigh梁的能量衰减估计。证明了梁的能量一致指数衰减是不可能发生的。在能量空间中,当梁的能量非一致衰减时,由初始条件得到了梁的能量多项式衰减估计。本文的方法是由相应无阻尼系统产生观测不等式和迹正则性结果得到的衰减估计。     

Experimental assessment of a wireless communications platform for the built and natural heritage

Wireless sensor networks have become extremely popular in a number of fields in recent years, the cultural heritage among them. To date, however, communications quality has not been technically validated in any of the various built (churches, museums, archaeological sites) or natural (caves, lava tubes) heritage scenarios. The present study establishes methodology for assessing the quality of wireless communications and validating the network used, both of which are essential to guaranteeing accurate long-term monitoring in heritage scenarios. Parameters such as signal strength, link quality, range and success rate were analysed with a view to preventing transmission failure and ensuring reliable monitoring for the preventive conservation of the cultural heritage.     

Novel models of intertemporal valuation: Past and future outcomes.

Temporal discounting refers to the reduction in the present subjective value of an outcome as a function of the temporal distance to that outcome. Though a number of mathematical models have been proposed to describe this time/value relationship, this search has largely excluded insights from the literature on memory decay. This study examines the utility of memory decay models by comparing the fits of 4 of these models to fits from established temporal discounting models using past and future temporal discounting data. These results (a) suggest that a single model describes valuation of both future and past outcomes; (b) indicate the exponential-power model, from memory decay literature, is statistically superior in fitting discounting data from both past and future outcomes; and (c) support the advancing perspective of the psychological interconnectedness of the future and past. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High purity pion beam at TRIUMF

An extension of the TRIUMF M13 low-energy pion channel designed to suppress positrons based on an energy-loss technique is described. A source of beam channel momentum calibration from the decay π⁺→e⁺ν is also described.