Assessing the Assessments: Improving Methodologies for Impact Assessment in Transboundary Watercourses

Transboundary impact assessment (TIA) has become an important environmental management tool, particularly where a project may have transboundary impacts. With the growing practice of TIA, it becomes important to consider the accuracy of the transboundary impact assessments that are being conducted. If TIA is a planning tool designed to provide a basis for making an informed decision, does it actually provide the necessary information? This paper summarizes lessons learned in pilot testing a methodology to assess the accuracy of TIAs.     

脉冲放电高能转化制备纳米粉体

综合介绍了脉冲电流通过细金属丝放电(pulsed wire discharge,PWD)制备纳米粉体的方法.讨论了影响纳米粉体,特别是晶粒尺寸的因素,以防止形成亚微米颗粒.因为达到电压峰值的丝的沉积能相当于丝的汽化能,因此,能夠计算出沉积能.随着所施加的能量增加,气体压力降低,介质气体的热扩散率增大,晶粒尺寸变小.在惰性气氛中,采用PWD工艺,由金属蒸气急冷可制备金属粉体.如果介质气体变为氧气或者氨气,就能制备氧化物、氮化物纳米粒子.要制备双金属合金、双氧化物或氮化物纳米粒子就必需采用双金属丝和不同的介质气体.采用PWD工艺,在有机气体或烟气中,能制备电磁屏蔽和导电浆料和其它用途的钝化纳米粒子.采用丝输送器而实现大量生产纳米粉体的PWD工艺一个实例证明了PWD工艺生产纳米粉体的可行性.     

Multi-objective discounted Markov decision processes with expectation and variance criteria

A multi-objective discounted Markov decision process (MDP) with expectation and variance criteria is discussed. First, difficulties in variance minimization are discussed and it is shown that variance minimization is much more difficult than the expectation optimization. Then, the multi-objective MDP with expectation and variance criteria is formulated as a multi-objective non-linear programming problem. An algorithm for finding a stationary satisfactory Pareto policy is proposed by applying the satisficing trade-off method of Nakayama. In the proposed algorithm, a decision-maker need not have a high degree of judgment and it is easy to take the balance of expectation and variance criteria and furthermore, the number of auxiliary optimization problems to be solved is quite small. Numerical examples show the efficiency of the proposed algorithm.     

Effects of titanium on magnetic properties of semi-processed non-oriented electrical steel sheets

The effects of titanium inclusions on magnetic properties of non-oriented electrical steel sheets were investigated. The magnetic induction and core loss of test specimens deteriorated as the titanium content increased. Electron microscopic study revealed that the deterioration was classified into two types: one was caused in the steels containing <0.016 wt% titanium by the “pinning effects” of titanium carbonitrides on the recrystallization of cold-rolled sheets, and the other occurred in the steels containing >0.016 wt% titanium by numerous (Fe, Ti)P precipitates in both grains and grain boundaries. This revised version was published online in November 2006 with corrections to the Cover Date.     

Direct Measurement of Fracture Energies of Brittle Heterogeneous Materials

A noncatastrophic fracture was shown to exist in the three-point bending test with a "hard-beam" machine when an artificially cracked or notched specimen was used. In this mode of fracture the energy produced by external work was transformed completely into the effective surface energy (fracture energy) of the specimen. The energy was measured from the load-time curve for the test. The fracture energies obtained by this method for plate glass were in the range 3 to 6 × 10³ ergs cm⁻², in good agreement with results obtained by other methods. The effective fracture energies of firebrick were about one order of magnitude larger than those of glass.     

Effect of antimony surface treatment on nitrogen absorption during batch annealing of an electrical steel sheet

Nitrogen absorption is usually observed during batch-type hot-band annealing of electrical steel sheets containing aluminium. This nitrogenizing causes the deterioration of magnetic properties, such as core loss and induction. In order to prevent nitrogenizing, we investigate an antimony treatment on the hot strip surface of electrical steel sheets containing aluminium. Potassium antimonyl tartrate and colloidal antimony oxides (Sb2O5) are effective against nitrogenizing. It seems that active sites on the surface of the hot strip after pickling are covered with antimony oxides to block the adsorption of nitrogen. Magnetic properties, after cold-rolling and continuous annealing of the nitrogenizing hot band, deteriorate due to small grains near the surface whose boundaries are pinned by aluminium nitrides.     

硫酸溶液中SUS304不锈钢旋转圆盘电极电流振荡现象的研究

硫酸溶液中SUS304不锈钢旋转圆盘电极在正向电位扫描时产生电流振荡现象。振荡电流所对应的电位范围以及电流振荡幅度与溶液温度,硫酸浓度、电位扫描速度以及电极旋转速度存在着对应关系.在电位线性扫描条件下,溶液温度高于35.0℃、硫酸浓度大于2.5mol·L~(-1)以及电极旋转速度不大干1000rpm时,可观测到电流振荡现象。电流振荡现象的产生与电极溶解过程、Cr_2O_7~(2-)的生成。O_2的离析及MCr_2O_7盐膜的生成和裂解有着密切的关系。