Galileo's tidal theory

The aim of Galileo's tidal theory was to show that the tides were produced entirely by the earth's motion and thereby to demonstrate the physical truth of Copernicanism. However, in the Dialogue Concerning the Two Chief World Systems Galileo did not explain some of the most significant aspects of the theory completely. As a consequence, the way the theory works has long been disputed. Though there exist a number of interpretations in the literature, the most widely accepted are based on ideas that are not explicitly articulated by Galileo in the Dialogue. This essay attempts to understand the way the theory functions in terms of Galilean physics. It is an interpretation of the theory based solely on Galileo's arguments--and one that reveals it to have had some unrecognized consequences. This interpretation indicates that Galileo's theory would not have worked in the manner he described in the Dialogue.     

Tides and tidal power in the Bay of Fundy

The Bay of Fundy in Eastern Canada has the highest tides in the world, with a range from low tide to high tide that can exceed 15 m in Minas Basin at the head of the Bay. Interest in harnessing these tides for the generation of electricity has raised challenging questions about the environmental impact of a tidal power development, and stimulated basic research which has elucidated the role of the tides in the general oceanography of the region.     

潮流发电机全向导流罩设计

为了适应我国海洋潮流低速的特点,设计了一种可以显著提高捕能效率的新型全向导流罩。为了降低制造成本,全向导流罩设计成对称式结构。全向导流罩适用于竖轴潮流发电机,通过罩在水轮机的外围,可以对任意方向的来流进行导流,显著提高了水轮机的捕能效率。     

鳞状潮流发电机设计

水轮机获能效果的大小对潮流能发电装置的发电功率起着决定性的作用。基于仿生学原理,文章设计一种鳞状潮流能水轮机结构。为提高鳞状潮流能水轮机的获能效率,在水轮机外围设置了全向导流罩。为提高潮流能发电装置整体的稳定性,设计了金字塔形的底座。     

走航式ADCP在感潮河段流量监测中的应用

在感潮河段受上游径流、潮汐的影响,水位、流速变化较快,水文现象极为复杂。采用传统的常规测验方法验证代表线,劳动强度较大,效率低下。而走航式ADCP(声学多普勒流速剖面仪)除可以快速测量断面流量外,也可以定点(固定垂线位置)通过WinRiver软件中的命令控制ADCP定时按时长获取垂线(代表线)流速、流向,应用上述方法在北江石角站完成感潮河段的流量连续测验,取得良好的效果,从而为感潮河段流量连续监测提供了一种新的手段。     

Global blue carbon accumulation in tidal wetlands increases with climate change

Coastal tidal wetlands produce and accumulate significant amounts of organic carbon (C) that help to mitigate climate change. However, previous data limitations have prevented a robust evaluation of the global rates and mechanisms driving C accumulation. Here, we go beyond recent soil C stock estimates to reveal global tidal wetland C accumulation and predict changes under relative sea level rise, temperature and precipitation. We use data from literature study sites and our new observations spanning wide latitudinal gradients and 20 countries. Globally, tidal wetlands accumulate 53.65 (95%CI: 48.52–59.01) Tg C yr⁻¹, which is ∼30% of the organic C buried on the ocean floor. Modeling based on current climatic drivers and under projected emissions scenarios revealed a net increase in the global C accumulation by 2100. This rapid increase is driven by sea level rise in tidal marshes, and higher temperature and precipitation in mangroves. Countries with large areas of coastal wetlands, like Indonesia and Mexico, are more susceptible to tidal wetland C losses under climate change, while regions such as Australia, Brazil, the USA and China will experience a significant C accumulation increase under all projected scenarios.     

The vertical distribution of dissolved oxygen and the precipitation by salt water in certain tidal areas

It has been shown that the lower layers of certain tidal waters under investigation contain less dissolved oxygen than the upper layers. Evidence has been presented to show that this phenomenon is caused by the stratification of the water due to the specific gravity of the under-run of sea-water, which cuts off vertical circulation, and to the subsequent depletion of the oxygen in the lower layers by natural agencies. The depletion of oxygen was found to be greatest in September. The precipitation and sedimentation of matter in tidal areas by sea-water have been presented in graphic form. These data are considered to be of particular interest from the viewpoint of fish and shellfish life.