Computation of particles’ ascent from a cavity behind passing shock wave

We study numerically the dynamics of particles of dispersed phase in a turbulent gas flow in planar shock waves (SWs) sliding along a solid surface with a depression of trapezoid shape. The ascent of particles from the cavity walls has been computed in the approximation of a rarefied gas–particle mixture. A considerable influence of the passing SW strength and the initial location of particles on the characteristics of particles’ ascent, the non-monotonicity of the dependence of the particle-ascent height on the initial longitudinal coordinate, and the SW Mach number, and a possibility of the formation of particles’ accumulation and removal zones on the depression bottom are shown.     

甘肃省滑坡泥石流灾害及其减灾对策

本文分析了甘肃省滑坡灾害成因的内在因素、环境因素以及外部触发因素,划分出了甘肃省的滑坡、泥石流灾害区。最后,提出了防灾减灾的对策。     

烟气流量对除尘效率测定的影响

除尘效率是衡量废气污染原治理设备性能的重要指标。因现场监测条件的制约，会出现除尘系统进出口烟气流量差距过大的现象，由此不能真实反映除尘系统的状况。本文通过对实测数据的分析说明：对高效率除尘器而言，进出口烟气流量相关1-1.5倍时，对除尘效率的计算可视为无影响。     

基于支持向量机的高速公路事件检测

针对交通领域中的事件检测(无事件模式和事件模式)模式识别问题,描述了支持向量机(SVM)支持的基本方法,建立了基于线性(linear function)、多项式(polynomial function)和径向基(radial basis function)3种核函数的事件检测SVM模型。采用高速公路路段I-880线圈数据集和事件数据集验证模型,结果发现:无论对于向北、向南或混合方向的事件检测,在3个SVM模型中,SVM(P)检测效果最好,SVM(L)最差。SVM算法具有避免局部最小,实现全局最优化,更好的泛化效果的优点,是高速公路事件检测的一种很有潜力的算法。     

Valuing Water Rights in Douglas County,Oregon, Using the Hedonic Price Method1

Abstract: This paper uses the hedonic price method to estimate the value of an acre‐foot of irrigation water in Douglas County, Oregon. The analysis uses detailed information from 113 arms‐length transactions of farmland for 2000 and 2001. The estimated willingness‐to‐accept of $261 to sell an acre‐foot of irrigation water is consistent with other studies and recent transactions in the study area. Estimates for the value of leasing water are provided using a range of discount rates and leasing periods.     

袋式除尘器气流组织的数值模拟分析

文章通过采用流体动力学CFD软件对袋式除尘器中单元模块的除尘空间气流组织进行数值模拟分析，给出了不同位置的布袋不同高度上的气流速度图，将模拟结果与实际工程运行情况进行对比，分析了其可靠性，为袋式除尘器的改进和设计提供了理论依据。     

Metal capital sustaining a North American city: Iron and copper in New Haven, CT

A detailed inventory shows that an average resident of the City of New Haven depends on a per capita capital stock of 9200 kg/c of iron and 144 kg/c of copper in the city infrastructure, buildings, transportation systems, and equipment. Of the iron stock 28% is in items such as rail cars and ships in ocean trade not permanently within the city, and 22% is devoted to receiving and delivering oil fuel to the city and its surrounding communities. Copper is principally used in the distribution of electric power and in water piping within buildings. The city's 9200 kg/c of iron stock-in-use is less than the 13,000 kg/c national average due to New Haven's lack of heavy industry and relatively small number of large buildings. The 144 kg/c of copper stock-in-use is only 58% of the overall value for the United States, but is comparable to that in cities such as Stockholm, Sweden. Attainment of a level of iron and copper services with contemporary technology in less developed countries to the level enjoyed in New Haven would require consumption of the presently identified world copper resources.     

Seismic monitoring and modelling of supercritical CO2 injection into a water-saturated sandstone: Interpretation of P-wave velocity data

This paper reports on an integrated laboratory and numerical simulation study of ultrasonic P-wave velocity response to supercritical CO₂ displacement of pore water in Tako sandstone. The analysis of dynamic velocity data recorded using an array of piezoelectric transducers mounted on a core sample showed that the P-wave velocities at different positions displayed a similar trend in time, i.e., an initial sharp fall followed by a more gradual decline. Considerable variations observed in the measured P-wave velocity reductions across the sandstone core could largely be attributed to the final state of saturation (e.g. uniform, patchy or in-between) attained by the two-phase fluids. Numerical simulation of the injection test using a simple 1D model was carried out to provide an estimation of the phase saturation changes underlying the measured P-wave velocity reductions. A second order polynomial correlation between the measured ultrasonic P-wave velocity reductions and the estimated CO₂ saturation was established. Comparison with the Gassmann velocities showed that the empirically established relationship marks a clear deviation from both the patchy and uniform saturation velocity curves.     

Automated Algorithms for Heuristic Base‐Flow Separation1

Abstract: The subjective nature of graphical base‐flow separation combined with the many applications of base‐flow time series derived from continuous streamflow data, motivates the development and application of automated algorithms for heuristic base‐flow separation. Base‐flow time series derived from gauged streamflow support diverse applications in engineering hydrology, catchment analysis, hydrogeologic investigations, regional low‐flow analysis, and recharge estimation. Whether based on graphical procedures for recession analysis or analytical expressions derived from fundamental equations of ground‐water flow, the variety of base‐flow separation algorithms belies the array of base‐flow definitions and interpretations that variously refer to dominant process, source, flow path, and characteristic response time. Algorithms that are invariant in their consistent – though heuristic – characterization of base‐flow response are particularly useful for interbasin comparisons of low‐flow characteristics and hydrologic regionalization. More adaptable algorithms provide application‐specific flexibility in allocating flow components like interflow to either quickflow or slowflow. Four widely used algorithms that produce consistent base‐flow time series using only gauged streamflow records are compared and contrasted with a complementary heuristic algorithm that incorporates hydrologic judgment explicitly, through manual parameterization. The utility of these inherently subjective algorithms is illustrated through a simple example of flow phase separation in a two‐component end‐member mixing model of dissolved chlorides in the Cuyahoga River.