SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN THE PIRACICABA RIVER BASIN,BRAZIL1

ABSTRACT: The spatial and temporal variability of dissolved oxygen (DO), biochemical oxygen demand (BOD), nitrate concentration and total coliform (TC) were investigated at nine sampling stations distributed along the main rivers of the Piracicaba River Basin, a 12,400 km² catchment located in São Paulo State, one of the most developed regions of Brazil. Spatially, a downstream impoverishment of water quality conditions was observed, as seen by the decrease of DO, and increase of BOD, nitrate, and TC. These changes were probably caused by accumulating downstream discharge of domestic and industrial sewage. Temporal evaluation of 18 years of data showed that DO decreased with time for the majority of the sampling stations, while BOD, nitrate, and TC increased. A law, approved at the end of 1991, proposed a new water tax for river water extraction for industrial and agricultural use. The amount of this tax is determined according to the water quality of the extracted water. Therefore, the evaluation of the water quality status in this basin is a first step to help resources managers to determine the values for this tax.     

MODELING HYDROLOGIC TIME SERIES FROM THE ARCTIC1

The general intervention model is applied to hydrologic and meteorologjc time series from the Canadian Arctic. The authors show how the model is able to account for environmental interventions, missing observations in the data, changes in data collection procedures, the effects of external inputs, as well as seasonality and autocorrelation. Methods for identifying transfer functions by making use of a physical understanding of the processes involved are demonstrated and sample applications of the general intervention model to Arctic data are shown.     

防洪新思路－气象工程防洪法初探

针对防治法－水利工程防洪法的缺点,提出一个全新的防洪思路－气象工程防洪法,通过从源头控制引起洪涝灾害的水源－降水的时空分布,达到控制水患灾害和充分合理利用水资源的目的,既可减少灾损,节省用于防洪的大量人力物力财力。     

性能化防火分析方法在大型地下商场中的应用

地下建筑火灾具有散热性差、烟气量大、人员疏散困难的特点,需要在消防设计和安全分析时予以足够的重视。该文利用性能化防火分析方法研究某大型地下商场在发生设定火灾条件下的烟气运动以及人员疏散特性,并通过安全疏散时间判据来评估人员能否全部安全疏散。     

机组行为、时间余量与飞行安全间的关系探讨

探讨机组行为、时间余量与飞行安全间的关系，为航空公司的机组训练和避免飞行事故及飞行事故征候的发生提供帮助。利用1996—2000年中国民用航空总局航空安全办公室下发的“飞行事故、航空地面事故和飞行事故征候统计的通知”中的资料，找出因机组行为错误导致的、与解决问题的时间余量关系密切的飞行事故和飞行事故征候案例。与飞行专家进行研讨和分析，探求飞行事故及其征候的发生与机组行为和时间余量间的关系。找出了因机组行为错误导致的、与解决问题的时间余量关系密切的飞行事故11起和飞行事故征候133起。其中因机组疏于监控飞机设备和状况、未发现问题存在或未明确所发生的问题的性质而无作为，使得解决问题的时间余量为零或接近零，从而无时间解决出现的问题，导致飞行事故3起和飞行事故征候96起；因机组发现问题存在并在明确所发生的问题的性质后，在一定时间余量内未能突破思维惯性的影响，做出了错误的决策，未能解决所发现的问题，导致飞行事故8起和飞行事故征候37起。飞行事故和飞行事故征候的发生与机组行为和时间余量的关系是，机组行为可以决定时间余量剩余的多少，时间余量的多少反过来决定机组采取何种措施解决当前的问题才能避免飞行事故和飞行事故征候的发生。     

三峡水库汛末不同时间蓄水对防洪的影响

为充分发挥三峡水库的综合效益，本在三峡水库汛末洪水特性分析基础上，对水库9月份各旬设计洪水进行频率和调洪计算，并给出了9月份不同时间蓄水下水库各旬洪灾的风险率和风险损失，据此分析了汛末不同时间蓄水对水库防洪的影响。结果表明，三峡水库9月份各旬的设计洪水均小于汛期设计洪水，且呈逐句递减的趋势，只要水库汛末提前蓄水的时间恰当，不会给水库防洪带来风险。例如，对于9月份1％设计洪水，水库9月16日以后蓄水的洪灾风险率和风险损失均为0。     

WATER QUALITY SAMPLING SCHEMES FOR VARIABLE FLOW CANALS AT REMOTE SITES1

ABSTRACT: Growing interest in water quality has resulted in the development of monitoring networks and intensive sampling for various constituents. Common purposes are regulatory, source and sink understanding, and trend observations. Water quality monitoring involves monitoring system design; sampling site instrumentation; and sampling, analysis, quality control, and assurance. Sampling is a process to gather information with the least cost and least error. Various water quality sampling schemes have been applied for different sampling objectives and time frames. In this study, a flow proportional composite sampling scheme is applied to variable flow remote canals where the flow rate is not known a priori. In this scheme, historical weekly flow data are analyzed to develop high flow and low flow sampling trigger volumes for auto‐samplers. The median flow is used to estimate low flow sampling trigger volume and the five percent exceedence probability flow is used for high flow sampling trigger volume. A computer simulation of high resolution sampling is used to demonstrate the comparative bias in load estimation and operational cost among four sampling schemes. Weekly flow proportional composite auto‐sampling resulted in the least bias in load estimation with competitive operational cost compared to daily grab, weekly grab sampling and time proportional auto‐sampling.     

黄磷厂废渣作水泥混合材的研究

本文较系统地研究了影响黄磷渣作水泥混合材的因素；推荐了提高黄磷渣作水泥混合材的掺量必须控制的条件；按推荐的控制条件，黄磷渣作水泥混合材的掺量可高达４０％以上。     

APPLICATION OF MODERN ORGANIZATIONAL CONCEPTS TO A LARGE WATER RESOURCE STUDY1

ABSTRACT: Modem management concepts were used to increase the efficiency and productivity of a large and complex water resource study conducted on two Delaware River components of the National Wild and Scenic Rivers System. The study analyzed the hydraulics of a 120 mile reach of the river using Rhodamine WT dye injected under medium-flow, low-flow steady-state, and low-flow-surge wave flow conditions. The study benefited from a decentralized management structure that used informal teams to attain quality control objectives, to overcome study difficulties, to secure substantial interagency cooperation, and to maximize limited financial and staffing resources.     

地震发生时间对人员伤亡影响的概率

本文用泊松分布表示家庭人数的概率分布,并假定在闲暇时间段人在室内的概率服从均匀分布,根据人在一天中的活动建立了不同时间段人在室内的概率公式。用一天中不同时间段人在室内的概率表示地震发生时间对人员伤亡的影响。