Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.     

岩石动态拉伸断裂特性的实验研究

采用新近发展起来的拉伸式Ｈｏｐｋｉｎｓｏｎ冲击装置（ＳＨＴＢ），对岩石切口圆柱断裂试样进行了动态拉伸断裂特性的实验研究。同时，利用ＭＴＳ试验机进行了岩石的静态拉伸断裂实验，成功地获得了岩石试样的断裂韧度及断裂能随加载率而变化的实验结果。对静态和动态破坏后的试样断口进行的扫描电镜观察进一步表明，试样断口形貌的复杂程度与其断裂耗能有着十分密切的联系。     

Lake Turkana,major Omo River developments,associated hydrological cycle change and consequent lake physical and ecological change

This study aimed to explore Lake Turkana's ecological reliance on hydrology and to determine the hydrological changes and consequences arising from the major hydropower and irrigation developments in the lake's basin. The major developments on Ethiopia's Omo River are especially significant as this river provides over 80% of the lake's annual freshwater influx and associated nutrients. The cascade of hydropower dams permanently dampens the natural hydrological cycles and lake level variability. The driving force of the flood influx to the lake is curtailed and the pattern of lake currents will adjust. Ultimately 80% of the river inflow to the lake will be regulated. Large volumes of water are required to initially fill the hydropower dam reservoirs. During 2015–16 when the huge Gibe III reservoir was filled, Lake Turkana's water level declined 2?m.The study has shown that large-scale irrigation schemes in the Lower Omo can potentially abstract 50% of the Omo River water, and that this would cause the lake level to shrink permanently to the detriment of the lake ecology. Possible lake level drops of over 15?m are demonstrated. The basin's natural capital is being replaced by large-scale plantation developments. The hydrological changes are drastic and the ecological consequences on Lake Turkana have not been fully understood. Without serious mitigation measures, Lake Turkana is a potential African Aral Sea disaster in the making, emulating what has happened to other great lakes such as Lake Chad.     

POS系统及其在航空摄影中的应用

描叙了POS系统的运行原理,并结合原理分析了POS系统在航空摄影应用时应该注意的偏心分量测量、POS设备初始化、数据精度控制及基站架设等问题,最终结合实际的航摄飞行要求对POS系统在实际航空摄影中出现的上述问题提出预防措施和解决办法。     

Comparative analysis of glacial and nival streamflow regimes with implications for lotic habitat quantity and fish species richness

Growing interest in the differential responses of glacial and nival rivers to climatic forcing, and in ecological distinctions between the two streamflow regimes, suggests the need for a better comparative understanding of how the annual hydrologic cycle differs with presence or absence of catchment glacial cover. In this study, timing and magnitude characteristics of the average annual hydrographs of five glacierized and four nival catchments in the southwestern Canadian subarctic are empirically identified and compared. Likely effects upon fish habitat are qualitatively assessed, and net fisheries potential is tentatively investigated using taxa richness data. The chief hydrological conclusions at P < 0.05 using Kolmogorov–Smirnov and empirical orthogonal function analyses are: (1) catchment glacial cover results in freshets that are longer, larger, and peak later than those experienced by the nival regime; (2) the winter baseflows of glacial rivers are also much higher on a unit‐catchment‐area basis; and (3) basin scale and degree of catchment glacial cover are of comparable importance in determining the magnitude of the annual hydrologic cycle. These differences arise from the greater availability, both in volume and over time, of meltwater in glacial catchments, which in part reflects the consistently negative alpine glacial mass balances observed both in the present study area and globally under historical climatic warming. Such regime distinctions result in increased spawning season and winter aquatic habitat availability, which may in turn offset negative habitat characteristics previously identified for glacial river ecosystems. While previous studies have suggested that glacial influences tend to decrease macroinvertebrate diversity and increase salmon populations, preliminary analysis of available fish species presence/absence data from the current study area tentatively appears to suggest similar or, perhaps, slightly higher fish taxa richness relative to nival streams; in all three cases, however, catchment lake cover may play a key hydroecological modifying role. The results strongly confirm and extend existing understanding of glacial–nival regime differences with respect to both streamflow and fisheries ecology, and raise new questions for future research. Copyright © 2005 John Wiley & Sons, Ltd.     

天生桥一级水电站混凝土面板堆石坝位移监测

天生桥一级电站混凝土面板堆石坝的填筑坝体位移监测通过水管式沉降仪和水平位移计进行。坝本内安装了５０支水管式沉降仪（瑞曲盒式）、３１支水平位移计（钢丝型伸缩仪）和２８支总压力计。监测结果表明，施工期末（１９９９年３月）最大坝体沉降是２．９４ｍ，相当于坝体高度的１．７％，施工期末堆石坝变形模量Ｅｒｃ平均４５ＭＰａ，为最大坝体变形，促使上游边坡出现裂缝以及面板浇筑前上游边坡明显沉降。     

On Some Kinds of Damage in Drums of High-Pressure Boilers

Kinds of damage in drums of high-pressure powerplant boilers in the places of welding of separation devices by austenite electrodes are described. Results of a complex study of damaged metal are presented. The mechanism of damage caused by contact (electrochemical) corrosion on the interface of two metals with different values of electrode potential is established. Measures for preventing the described kinds of damage are recommended.     

Screening model for assessing ‘cost’ of minimum flow requirements in the Svartå River,Sweden

The minimum flow requirements in the Svartå River in Sweden are directed at maintaining fishlife and providing suitable dilution for waste flows. The implications of varying the minimum flow requirements in the river are examined using a mixed integer optimisation model. The model is formulated as a modified method-of-weights technique with the economic issues of hydro-electricity generation, irrigation and urban water supply placed in the objective function and the minimum flows specified within the constraint set. The integer component of the model is required to model the operating policy at the major flow regulation facility in the system and the restricted validity of the irrigation permits. Application of the model shows that in dry years where competition between minimum flow levels and the other economic uses, is most intense, the levels achieved by the various economic objectives are only slightly reduced even with significant increases in the minimum flow requirements. Variations in minimum flow requirements of up to 45% only produce changes of 10% or less in the economic objectives. The lack of sensitivity of the objective levels is due primarily to the level of control exerted indirectly on the whole system in dry years by the release regulation policy and the restricted validity of the irrigation permits. In normal to wet years these policies are not as restrictive and more choice is available. In such years, however, there is generally sufficient water to satisfy all requirements and allocation is not a critical issue. The model itself is formulated generally so that a range of scenarios beyond those examined specifically in the paper can be considered.     

水电机组性能参数综合测试系统综述

介绍了水电机组性能参数综合测试系统, 7个子功能装置及其分析平台。阐述了该系统能实现对水电机组性能指标（安全性、稳定性、可靠性、经济性）的全面科学评价,彻底改变我国水电机组关键监测设备依赖进口的现状,提高我国水电机组监测仪器设备的自主创新能力与装备水平,支撑科技创新,服务国民经济与社会发展。     

推行材料检验见证取样送检制的体会和建议

在水利基建工程中存在着一些因工程建筑材料不合格而留下的工程隐患 ,其原因之一是材料送检时没有实行见证取样制度 ,造成送检材料与实际施工用料质量不一致 ,为了防止这种质量事故 ,避免事后检测、处理造成的经济损失 ,应在水利工程建设中推行材料检验见证取样送检制     

和平水电站引水隧洞衬砌裂缝原因分析及修复设计

根据和平水电站引水隧洞衬砌开裂破坏的情况 ,从地质条件、设计情况、材料强度和施工情况分析该隧洞钢筋砼衬砌裂缝宽度严重超标的原因 ,拟定相应的加固处理措施 ;介绍隧洞衬砌按限裂设计和钢管砼组合衬砌钢管厚度的计算方法     

砼强度质量评定应用软件的实现及应用

阐述了水利、工业与民用建筑等工程砼强度评定的有关规定，编制了砼强度质量评定的专用软件，并以实例加以说明。     

滹沱河洪水演进模型探讨

黄壁庄至北中山为滹沱河主干流,受人类活动的影响,常年处于干涸状态,洪水的演变规律发生了较大变化.本文采用河北汇流模型对该河段洪水的演变规律进行了模拟分析,取得了令人满意的结果,可供广大水文工作者在今后干旱平原河道洪水预报工作中参考.     

江西省2005年暴雨洪水特性及水文测报工作

对江西省2005年暴雨洪水特性进行了分析,并对防汛水文测报工作和水文防御山洪地质灾害的经验做了总结.     

水工监测传感器指标使用误区的探讨

本文旨在讨论目前岩土工程中使用的传感器技术指标及其含义，希望通过探讨以弄清楚这些指标的含义及指标对评价传感器的意义。由于传感器是用于测量工程物理量的，因此，引人目前在国际上通用的测量与误差的概念，以国家现有的测量术语的定义为准来描述传感器的指标。     

彭水电站超大型压力钢管制造安装技术

彭水电站引水隧洞压力钢管最大直径14．0m，最大管节重量46t，大直径、大吨位及复杂的施工环境给压力钢管制作、安装带来了很大施工难度。文章结合工程施工实际，论述了彭水电站超大型压力钢管制作、安装的主要施工程序及措施，以便类似工程参考。     

澄碧河水库溢洪道闸门启闭机设备改造及考核测试

澄碧河水库溢洪道闸门控制系统部分设备陈旧老化已超过使用年限。为此,对相应控制部分进行改造,在对原有的液压系统和配电改造的同时,新建闸门计算机自动监控系统。实践证明,澄碧河水库溢洪道闸门控制设备的更换改造,实现了多种方式操作和计算机自动监控,具有闸门开度指示及各种运行状态或事故记录与查询、泄洪水量统计、打印和保护动作报警等多种功能,为澄碧河水库防洪度汛提供了安全保障。     

Ansys软件在工程设计中的应用

通常人们采用《水利水电工程钢闸门设计规范DL/T5013-95》(以下简称《规范》)算法来设计船闸人字门。这种算法只能对人字门的应力进行分析,而人字门的应变及动态特性目前还没有较为有效的方法。Ansys应用于船闸人字门的静态、动态特性的分析计算,计算结果表明,将Ansys应用于船闸人字门的设计是可行的。     

百色水利枢纽地下厂房系统存在的主要地质问题及处理措施

百色水利枢纽地下厂房系统地质条件复杂,存在诸多不利因素,针对百色水利枢纽地下厂房系统存在的主要地质问题,介绍在设计、施工中所采取的处理措施。