Use of Potassium for Treatment and Control of Zebra Mussel Infestation in Industrial Fire Protection Water Systems

Zebra mussels, first discovered in the Great Lakes in 1988, have frequently been detected in fire protection systems. However, the potential for large-scale infestations has not been established. It is clear that even small numbers of mussels can cause problems in areas that have small-diameter piping or in sprinkler system nozzles, if shells are flushed down-stream during emergency use.This paper will discuss the development of a method of zebra mussel control that limited interference with normal system operations when used at Niagara Mohawk's Dunkirk Steam Station. Because oxygen is often depressed in these systems and limits mussels survival and growth, it was established that by monitoring oxygen alone, or in combination with veliger or mussel larval monitoring, high-risk areas for mussel infestation could be determined. In previous laboratory research, it had already been determined that concentrations of potassium in excess of 100 mg/L would lead to quick mortality in adult zebra mussels. These results, along with a biofouling risk assessment completed at Dunkirk Steam Station, were used to develop and implement a successful treatment of the high-risk areas in the plant's fire protection water systems using potassium in the form of potash as the controlling agent.     

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Cusp磁场中CZ硅氧浓度分布的数值模拟

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弹簧卷绕仿真系统中的碰撞检测

由于数控卷簧机卷绕刀具较多且刀具的运动时序较为复杂,因此对刀具之间可能发生的碰撞进行检测尤为重要。结合弹簧卷绕的动作特点,采用基于轴向包围盒的碰撞检测算法对可能产生碰撞的物体在仿真系统中进行了碰撞检测,对包围盒的表示、干涉及碰撞响应等作了阐述。实验表明,系统增强了仿真画面的真实感和实用性,操作者可以根据碰撞仿真结果进行处理,从而有效避免了在实际卷簧过程中刀具间可能产生的相互碰撞。     

基于运动控制器的卷簧机数控系统研究

设计了一个专用于自动卷簧机的四轴联动数控系统.该系统基于Windows XP操作平台,以PMAC运动控制器为核心并且具有开放式体系结构.重点阐述了数控系统的硬件构成和系统软件的结构设计,以及界面结构、数据通讯、伺服控制等.实验表明:该系统可以满足数控卷簧机的要求.     

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