Quantized control settings based tuning of a heaving wave energy converter in irregular seas

The increasing awareness of environmental issues attracts more attention on environmentally friendly energy sources. This leads to increasing research on effective use of renewable energy sources. Among them, wave energy offers a high potential. The wave energy converter systems used for transforming the wave energy into electrical energy have been a main research topic for decades. However, only a few of these systems has been successfully implemented. There seems to be some technical problems one of which is on their control applications. It has been reported that by means of appropriate control implementation, the performance of the wave energy converter system could be improved considerably. In literature, many different control techniques are reported. They appear to be weak due to implementation related restrictions. The present study proposes a novel control technique that is far more practical based on quantization of control settings. Various quantization levels and their effect on system power capture performance are studied. The technique assumes use of realistic off-the-shelf components with realistic features. The proposed method utilizes time-series-analysis technique with online parameter estimation feature. This new method does not require any knowledge of previous or future states of any of the system or sea state parameters, but only the currently available and measurable ones. The approach of the new control technique sets it apart from most of the previously reported ones. Therefore, the proposed technique is not only very much practical but also very much useful in improvement of the system power performance relative to passive techniques.     

Sorption and desorption of lindane by wood charcoal in fixed‐bed reactor

Abstract

Sorption and desorption of lindane (y‐HCH) by wood charcoal (WC) and wood charcoal treated by 1N HNO₃ (WCT) in fixed‐bed reactor (FBR) were investigated in this study. WCT revealed a better performance than WC, in removing lindane in FBR. The breakthrough of lindane was significantly affected by the size of WCT, flow rate to the FBR, and depth of WCT bed. The removal of lindane in the presence of mixture of other pesticides was considerably reduced. The design parameters for FBR were calculated based on the bed‐depth service time (BDST) approach. Many parameters Viz. depth of sorption zone, velocity of sorption, sorbent use rate, critical bed‐depth, bed efficiency, and service time, were determined for design of the fixed‐bed. Using the material balance principle, the characteristics of the wave‐front were evaluated and found that the wave‐front velocity is approximately equal to the sorption velocity determined from the BDST approach. Desorption studies were performed in dilute organic solvent media and they gave an excellent performance in regeneration process.     

电梯结构噪声分析和控制

文中根据民用电梯的一般结构布局,通过对声传播途径分析,得到电梯噪声扰民是受结构噪声影响的结论。通过对电梯系统和电梯与支架组成系统的力平衡分析,得出电梯结构噪声主要是主机支架设计不合理和安装不当产生的。文章提出了结构噪声防治措施,并对结构噪声扰民的多台电梯实施了工程控制措施,均取得了预期的降噪效果。     

超声波强化γ-Al_2O_3催化臭氧氧化法降解2,4-二硝基苯酚

采用超声波强化γ-Al_2O_3催化臭氧氧化法降解模拟废水中的2,4-二硝基苯酚,考察了超声波对降解反应的强化作用及γ-Al_2O_3加入量、臭氧流量、超声波功率等对2,4-二硝基苯酚降解的影响.实验结果表明:2,4-二硝基苯酚在超声波强化γ-Al_2O_3催化臭氧氧化作用下的降解过程符合一级表观动力学;在2,4-二硝基苯酚质量浓度为20.00 mg/L、γ-Al_2O_3催化剂加入量为1.5g/L、臭氧流量为61 mg/min、超声波功率为300 W、反应时间为60 min时,2,4-二硝基苯酚的降解率达96.4%.     

带坞舱船舶尾舱消浪装置消浪性能研究

目的 带坞舱船舶尾部具有与外界连通的自由液面,由于船舶运动会在坞舱内产生波浪,形成有害的波浪砰击,影响舱内装备的正常作业。针对这一问题,系统地对带坞舱船舶尾舱内的消浪方案进行模拟与优化,提出一套具有良好消浪性能的消浪装置方案。方法 以荷兰皇家海军两栖运输船为目标进行三维建模,使用CFD方法对其进行不同波浪下船舶响应模拟和分析,监测船舶的运动响应和舱内多个监测点的波高情况,使用多孔挡板为基础,给出一套消浪装置,并进行带有消浪装置方案的船舶响应模拟,评估该消浪装置方案的消浪性能。结果 对舱内首端和侧壁布置多孔板消浪装置,消浪效果可达40%~50%,验证了该消浪装置的可行性。结论 采用多孔介质区域模型对带有多孔介质消浪装置的整船进行数值模拟,在计算效率远高于对实际物理模型建模的同时,可以得到较好的消浪效果。     

倏逝波光纤传感器快速检测诺氟沙星

基于间接竞争免疫分析原理,利用倏逝波光纤生物传感平台研发了一种诺氟沙星检测方法,实现了水中诺氟沙星的快速､灵敏检测.研究表明,诺氟沙星检测的优化条件为:抗体浓度为1μg/mL､预反应时间为1min,反应时间为4min.优化条件下,诺氟沙星检测限可达1.89μg/L.包被抗原修饰的光纤探头与荧光标记诺氟沙星抗体具有良好的特异性和稳定性,可重复使用400次以上.自来水､景观水､二沉池出水等水样的加标回收实验结果表明,该传感器具有良好的精密度和准确性,受环境基质的影响较小,能够用于实际水样中诺氟沙星的快速检测.     

历史演变法原理与演变曲线板

根据杨鉴初的历史演变法原理，对苏皖沪（３０°～３６°Ｎ，１１５°～１２５°Ｅ）１９７１ ～１９９７ 年最大震级（ ＭＳ） 形成的时间序列，先进行迭次平滑，再据这些逐趋光滑的地震活动历史演变曲线的外形特征及数值，找出它们之间的联系规律与各自的变化规律：超前性、近似性、准对称性与渐变性。并根据这些规律性制成时间序列演变曲线板：近似板、旋转板与折迭板，对逐年最大震级进行外延验证，以及对１９９８ 年的最大震级做出预报。结果表明：用演变曲线板量取的时间序列外延预报值，与实况的差值都能小于｜０ ．５｜ 级。