滤料粒径对给水曝气生物滤池运行稳定性的影响

利用给水曝气生物滤池(UBAF)处理刘屋洲水源水,考察了不同陶粒粒径对氨氮、高锰酸盐指数的去除效果以及水头损失变化的影响。结果表明,陶粒3～5 mm的UBAF对氨氮、高锰酸盐指数的去除效果较高,但是其水头损失较大,且反冲洗前后水头损失变化偏大,不利于UBAF稳定运行。陶粒6～10 mm的UBAF运行状况良好,氨氮的去除率为73.8%,高锰酸盐指数的去除率为18.6%,滤池24 h过滤水头损失<0.4 m,反冲洗前后过滤水头损失变化量<5 cm。其出水氨氮和高锰酸盐指数均达到《生活饮用水卫生标准》(GB5749-2006),滤池的水头损失小,反冲洗前后也变化甚微。进一步的实验表明陶粒破碎会导致滤料粒径级配变化,使得水头损失增加。     

Non-intrusive characterization of the redox potential of landfill leachate plumes from self-potential data

Contaminant plumes (e.g., associated with leakages from municipal landfills) provide a source of natural electrical potentials (or "self-potentials") recordable at the Earth's surface. One contribution to these self-potentials is associated with pore water flow (i.e., the "streaming potential"), and the other is related to redox conditions. A contaminant plume can be regarded as a "geobattery": the source current potentially results from the degradation of the organic matter by micro-organisms, which produces electrons. These electrons are then carried by nanowires that connect bacteria and thorough metallic particles that precipitate in areas of strong redox potential gradient. In the case of the Entressen landfill (South of France), reported here, the hydraulic head differences measured in piezometers outside the contaminant plume is strongly linked to the surface self-potential signals, with a correlation coefficient of -0.94. We used a Bayesian method that combines hydraulic head and self-potential data collected outside the contaminated area to estimate the streaming potential component of the collected self-potential data. Once the streaming potential contribution was removed from the measured self-potentials, the correlation coefficient between the residual self-potentials and the measured redox potentials in the aquifer was 0.92. The slope of this regression curve was close to 0.5, which was fairly consistent with both finite element modelling and the proposed geobattery model.     

三峡库首移民安置区土地资源、移民经济状况及移民满意度的调查与分析

针对三峡工程蓄水和移民搬迁对库首地区农业生产和居民生活造成的影响,对移民安置前后三峡库首地区的秭归、兴山、巴东等县乡镇土地资源状况进行了统计分析,并选择典型乡镇移民户作为研究对象,实地调查了移民安置区移民户的经济收支情况及其对移民安置的满意度。结果表明：三峡工程蓄水后,库区低海拔地区耕地淹没,农村可用耕地总量减少,人均耕地也有所减少,人地资源矛盾比较突出。移民主要收入来源为劳务、种植业和养殖业收入,其中劳务收入比例较大,农户家庭经济支出主要是以生活支出为主,移民搬迁对部分农民经济收入产生较大影响。移民搬迁以后,库区农村的居住环境、住宅条件、生活条件和交通条件均较移民前有明显改善,农户普遍比较满意。库首地区的移民政策落实较好,大部分人对未来发展充满信心,对三峡工程表示支持和肯定。搬迁安置对农村生态环境状况产生了影响,存在自然灾害和病虫害增多,农村废弃物处理设施不足等问题,应当引起政府对库区生态环境问题的足够重视。〖     

GROUND WATER DROUGHT MANAGEMENT BY A FEEDFORWARD CONTROL METHOD1

ABSTRACT: Management of a regional ground water system to mitigate drought problems at the multi‐layered aquifer system in Collier County, Florida, is the main topic. This paper developed a feedforward control system that consists of system and control equations. The system equation, which forecasts ground water levels using the current measurements, was built based on the Kalman filter algorithm associated with a stochastic time series model. The role of the control equation is to estimate the pumping reduction rate during an anticipated drought. The control equation was built based on the empirical relationship between the change in ground water levels and the corresponding pumping requirement. The control system starts with forecasting one‐month‐ahead ground water head at each control point. The forecasted head is in turn used to calculate the deviation of ground water heads from the monthly target specified by a 2‐in‐10‐year frequency. When the forecasted water level is lower than the target, the control system computes spatially‐varied pumping reduction rates as a recommendation for ground water users. The proposed control system was tested using hypothetical droughts. The simulation result revealed that the estimated pumping reduction rates are highly variable in space, strongly supporting the idea of spatial forecasting and controlling of ground water levels as opposed to a lumped water use restriction method used previously in the model area.     

钛制高尔夫球头成形工艺研究

阐述了高尔夫球头的发展史及设计高尔夫球头的基本原理。对钛制高尔夫球头的成形工艺做了初步研究。     

Introducing a Low‐Head Dam Fatality Database and Internet Information Portal

Low‐head dams can cause dangerous currents near the downstream face of the structure. Fatalities at low‐head dams with such currents, often referred to as “drowning machines,” are poorly documented. This technical note presents a new database of fatalities at low‐head dams in the United States together with an interactive map and web‐based user interface. The primary purpose of the system is to raise awareness, generate interest, and educate the general public and decision makers regarding these dangerous structures and the need for remediation. The database was designed as a normalized relational database of event dates, severity, location, reporter, and other circumstances. The open‐access user interface allows the general public to browse fatal incidents by geographic location and to read incident circumstances. The system allows submission of new contributions from users including all metadata needed to characterize the incident. The database is structured to include documentation verifying each entry. The site can be viewed at http://dams.byu.edu/ .     

提高煤矿无定量斗式箕斗提升系统安全性能的新途径

提出了一种基于天轮传感器的新型箕斗提升定重装载系统;探讨以该系统为基础的无定量斗式定重装载形式、数据处理以及装载控制实现方法;研究以模糊神经网络为基础的智能数据处理与控制方法,有效解决了称重系统中因交叉灵敏度而导致的稳定性差、可靠性低等生产安全问题。实现老矿井箕斗提升系统特别是无定量斗式箕斗提升系统的定重装载改造,对煤矿提升系统安全、高效运行具有重要意义。     

控制棒驱动机构与反应堆堆顶组合模型的抗震分析

目的获得控制棒驱动机构(CRDM)和反应堆堆顶组件(RHP)在地震作用下的动力学响应。方法建立控制棒驱动机构与反应堆堆顶组件的有限元组合模型,采用ANSYS软件对模型开展三维非线性抗震分析。分析模型中分别用梁单元、杆单元和弹簧单元等模拟堆顶的各个部件,考虑控制棒驱动机构抗震支承板之间、抗震支承板与抗震支承环之间的相互碰撞作用。此外,将电缆托架和电缆桥组件的梁模型也加入到组合模型,而不是简单地将其简化为集中质量,可减小该部分质量分配不真实对抗震分析结果带来的误差。结果利用ANSYS软件时程法中的直接积分法完成了组合模型的抗震分析,提取了控制棒驱动机构和反应堆堆顶组件各部位应力评定所需的载荷。结论较为准确地模拟了抗震板之间的碰撞作用,得到了各截面的载荷,可为设备应力分析提供输入。     

Characteristics and clinical outcomes of head-injured cyclists with and without helmets in urban and rural areas of Taiwan: A 15-year study

Objective: Bicycle riding is increasingly popular in Taiwan, but the number of cyclists injured and cyclists' death rates are both increasing. The aim of this study was to investigate the different characteristics and clinical outcomes of traffic accident–related head injuries among cyclists in urban and rural areas.

Methods: Records of 812 patients (533 urban and 279 rural) admitted to 27 hospitals in Taipei City and Hualien County as the result of a traumatic head injury while bicycling between 1998 and 2013 were retrieved for study. Demographics, details about the accident, protective helmet use, and clinical outcomes were then subjected to analysis.

Results: Urban victims were more likely to be injured during morning and early evening rush hours and rural victims during the day; most urban victims were between 19 and 34 years of age and injured in the slow lane; rural victims tended to be younger or older and were injured in the fast lane (all P ≤.001). Riders who wore a helmet were less likely to suffer loss of consciousness (odds ratio [OR] = 0.31), amnesia (OR = 0.069), neurological disorders (OR = 0.205), or facial fractures (OR = 0.369). Older age, more severe head injuries, and bicycle–motor vehicle collisions influenced the severity of symptoms on admission and the residual effects at discharge.

Conclusions: Differences in the characteristics of injuries in urban and rural areas and the utilization of protective helmets may help government authorities adopt appropriate policies to promote safer and more enjoyable cycling.