高压加热器的滑参数启动方式

滑参数启动高加可取得更好的安全经济性,但在许多中小型电厂,自投产后高加一直采用定参数启动。本文详细介绍了高加滑参数启动的操作步骤和要点,为需要改进的机组提供参考。     

RESPONSIVE BIOREMEDIATION: REGULATING THE UNCERTAINTY,ASSESSMENT, AND NEGOTIATION FOR COASTAL DEVELOPMENTS IN HAINAN,CHINA

Land reclamation and dredging have a damaging effect on marine and coastal ecology. This study rationally analyzes the conflicts in the approved environmental impact assessment (EIA), including the negligence of the direct and indirect effects on coastal and marine habitats, the short circuit of the EIA procedures among stakeholders, and the insufficient marine environmental restoration schemes. This study also promotes awareness among the stakeholders so they will understand the direct and indirect effects of land reclamation on marine and coastal ecosystems, as well as the indications if they follow the EIA procedures, and implement a responsive marine bioremediation before and during the dredging process. By taking the Ocean Flower Island in Hainan, China as an example, this study applied the responsive oyster-seagrass-coral filtration bed system before and during the dredging process to maintain the water turbidity and suspended sediment concentration below the tolerance limits of the coral reefs in the adjacent areas.     

Concurrent monitoring of vessels and water turbidity enhances the strength of evidence in remotely sensed dredging impact assessment

Remotely sensed assessment of dredging impacts on water turbidity is straightforward when turbidity plumes show up in clear water. However, it is more complicated in turbid waters as the spatial or temporal changes in turbidity might be of natural origin. The plausibility of attributing turbidity patterns to dredging activities would be greatly enhanced when demonstrating association between dredging infrastructure and water turbidity. This study investigated the possibility to strengthen the inference of dredging impact while simultaneously monitoring vessels and water turbidity in the northern Poyang Lake, China, where dredging was first introduced in 2001 and rapidly extended onwards. Time-series of Landsat TM and MODIS images of 2000-2005 were used to estimate the distribution and number of vessels as well as water turbidity. MODIS images revealed a significant increase in water turbidity from 2001 onwards. Landsat TM image analysis indicated a simultaneous increase in the number of vessels. Regression analysis further showed a highly significant positive relationship (R2=0.92) between water turbidity and vessel number. Visual interpretation of ship locations led to the conclusion that clear upstream waters developed turbidity plumes while passing the first cluster of vessels. We concluded that dredging caused the increase in water turbidity, and simultaneously monitoring the water turbidity and vessels enhanced the strength of evidence in remotely sensed dredging impact assessment.     

城市河湖底泥疏浚对水生态的影响分析与对策探讨

随着城市的发展,城市河湖中底泥淤积问题正逐渐导致城市河湖丧失其原有的功能.传统的应对措施主要是采用底泥疏浚等工程措施,但多年的实践发现,在城市河湖底泥疏浚中暴露了诸多问题.通过对大量文献调研整理,分析了城市河道底泥疏浚中的效益以及负面影响.最后,对城市河湖底泥疏浚的对策问题进行了深入地探讨.     

Suspended sediment effects on walleye (Sander vitreus)

Environmental windows are seasonal restrictions imposed on dredging operations in the Great Lakes and other waterways of the United States. Such restrictions often generically assume that sediments resuspended by dredging result in adverse impacts to fish; this is the case in western Lake Erie where the environmental window was established due to potential impacts on walleye (Sander vitreus). To address this concern, laboratory studies mimicking sediment resuspension during dredging operations in western Lake Erie were conducted to determine whether suspended sediments affect walleye eggs and fingerlings. Newly laid eggs and 45- to 60-d old fingerlings from separate hatcheries were exposed for 72-h under flow-through conditions to 0, 100, 250, and 500 mg/L total suspended sediment (TSS). Fingerlings, eggs, and newly hatched larvae were analyzed for multiple lethal and sublethal endpoints. Data indicated no significant effects of suspended sediment on egg hatch success or fingerling survival after three days of exposure. No significant differences were observed when comparing percent egg viability in the control with any TSS treatment; however, a downward trend was observed at 500 mg/L. No significant differences were observed during comparisons of fingerling gill lamellae in the control with any TSS treatment; however, a statistically significant difference was observed when comparing gill lamellae in the control with the original supply animals. No significant differences were found between control means and unexposed eggs or any TSS treatment. These effect data for walleye will serve to better inform the setting of environmental windows for this species in western Lake Erie.     

海滨钛锆砂矿资源的船采技术

本文以海南海滨钛锆砂矿资源的赋存条件和开发现状为依据,论证了发展船采工艺的必要性、可行性和经济上的合理性。     

Assessing the Performance of Evapotranspiration Covers for Municipal Solid Waste Landfills in Northwestern Ohio

Evapotranspiration (ET) covers have gained considerable interest as an alternative to conventional covers for the final closure of municipal solid waste (MSW) landfills, but often produce higher rates of percolation in regions that receive more than 32??cm?year-1 of precipitation. The goal of this project is to design ET covers for MSW landfills in northwestern Ohio (long-term annual rate of precipitation of 83??cm?year-1) that produce rates of percolation <32??cm?year-1, the rate considered acceptable by the Ohio Environmental Protection Agency (OEPA), and promote habitat restoration. To attain this goal, an adequate soil water-storage capacity was provided using dredged sediment amended with organic material. Two plant mixtures were tested to evaluate the performance of ET covers immediately following construction (immature plants seeded onto the soil) and in the future (mature plants transplanted from a restored tall-grass prairie that is more than 10?years old). ET covers were constructed in drainage lysimeters (1.52-m diameter, 1.52-m depth) and watered at a rate of 91.12 to 95.72??cm?year-1, which included simulated 100-year rain events (11.7?cm over 24?h) in July and October. During the 1-year monitoring period, the ET covers using the mature plant mixture produced considerably less percolation (0.12 to 11.44??cm?year-1) than the covers with the immature plant mixture (6.71 to 24.16??cm?year-1). Thus far, all ET covers have produced rates of percolation less than the maximum standard by the OEPA, and they will continue to be monitored.     

Factors affecting the distribution and abundance of aquatic plants in a navigable Lowland river; the River Nene,England

Investigations were conducted into the causes of a decline in the abundance of rooted aquatic plants in the River Nene. These were formerly troublesome to navigation and obstructed summer storm flows and were regularly cut by Anglian Water until 1976. After 1977 plant growth caused only localized problems so cutting ceased. An investigation into the causes of the plant decline was initiated in order to provide predictions for management decisions about the future use of machinery and personnel. It was concluded that there was a natural loss of plants by scouring in the abnormally high flows of 1976/7 winter. The regular pattern of maintenance dredging, which had been implemented following water industry reorganization in 1974, was shown to suppress abundance for at least five years after dredging. These two sequential events had lowered abundance over the navigable Nene to levels which no longer warrant weedcutting.     

堆场疏浚淤泥沉降规律计算

基于淤泥颗粒在水中的受力情况和管道射流基本理论,建立了适用于堆场淤泥颗粒的基本运动方程,得到了淤泥颗粒的沉降速度分布图、水平管道射流各断面上的速度分布图和不同断面处轴向速度分布图。通过拟合淤泥颗粒在堆场中沿垂向、轴向和径向的运动规律,构建了堆场主沉降区内淤泥颗粒粒径范围从0.35～300μm沉降历时17h的分层沉降模型,大致模拟出淤泥沉降规律。淤泥颗粒粒径呈现扇形分布,沿堆场方向沿程递减分布,砂粒在堆场的前250m沉降完全,粉粒沿堆场水流方向依次沉降,黏粒大部分悬浮在水中,有利于后期实现堆场空间的有效利用和疏浚淤泥的资源化利用。     

吴川市鉴江河流治理规划设计的实践探讨

随着我国经济的发展和人民生活水平的提高,人们对河流提出很多新要求。本文结合吴川市鉴江河流治理的实际,对河流治理规划设计的实践进行了探讨,从而有效提高鉴江河道的防洪能力,减轻或避免洪涝灾害,使围内社会环境和生态环境得到明显改善。