Inertial waves in a fluid partially filling a cylindrical cavity during spin-up from rest

Abstract

Inertial waves are excited in a fluid contained in a slightly tilted rotating cylindrical cavity while the fluid is spinning up from rest. The surface of the fluid is free. Since the perturbation frequency is equal to the rotation speed resonance occurs at a critical height to radius aspect ratio of the fluid. Detailed study of a particular inertial wave shows that in solid body rotation this “eigenratio” agrees with predictions from linear inviscid theory to within 0.5%. Measured time dependence of the eigenratio during spin-up from rest is a function of the tilt amplitude and agrees favorably with predictions from a numerical study. Mean flow associated with the inertial wave becomes unstable during spin-up and in the steady state. A boundary for the unstable region is found experimentally.     

基于新编《系列世界地图》的全球板块分布图

采用新编《系列世界地图》绘制出一套四种全球板块分布图,具体分为,“东半球版”、“西半球版”、“北半球版”和“南半球版”.其中,“东半球版”和“西半球版”为“经线全球板块分布图”,适用于反映东、西半球的板块构造分布;“南半球版”和“北半球版”为“纬线全球板块分布图”,适用于反映南、北半球的板块构造分布.基于《系列世界地图》的全球板块分布图以东、西、南、北四种视角,从经度、纬度两种方向,将全球板块构造以多元化的形式地表达出来,为深入研究板块相互作用和运动机制,提供一种新的图形工具.     

世界时区图动态模拟与显示技术

以世界时区的概念为基础,阐述了世界时区图显示与模拟的总体构想、应具备的基本功能以及具有动态变化的特点,同时,着重提出了动态模拟时区渐变的RGB数学模型,并实现了世界时区动态模拟与显示.     

Transnational mining corporations and sustainable resource‐based livelihoods in Sierra Leone

This paper draws from world‐systems and sustainable livelihoods approaches to analyze the connections between multinational exports of rutile (titanium oxide), diminished ecological resources and resource‐based livelihoods, and gendered household dynamics in a peripheralized mining region in Sierra Leone. The discussion focuses on how the extraction of mineral resources instigated by exogenous capital investors forces links to household transformation, particularly the vulnerability context of women. Using archival records and field survey data, the case study of rutile mining in southwestern Sierra Leone connects the low‐waged mining labour of traditional resource‐based subsistence communities and deepening marginalization of and financial pressures on women in mining households to global mineral markets. The study focuses on women's coping mechanisms that are embedded within traditional social networks in relation to an external intervention, a low‐tech mechanical cassava grater, intended to strengthen their livelihoods. It finds that the potential for this transformation is impeded by sociocultural, environmental and financial limitations.     

Continuity markers as an aid for children in finding the peripheral continuity of world maps

ABSTRACT

Many map readers, including both children and adults, find it difficult to determine where they would be located along the edge of a world map after crossing that edge. Different types of markers have long been drawn close to the map’s edge – for example, in an atlas – to help map readers identify the map upon which they will find themselves if that edge is passed. In this study, a method similar to that used to show the continuity between maps in an atlas has been tested to determine whether continuity markers can also be used to help map readers find a world map’s actual peripheral continuity. The study involved children between the ages of 10 and 13 years and showed that continuity markers do help children determine the map’s actual peripheral continuity, in combination with a lesson that describes how to find the actual peripheral continuity of a world map. This article, therefore, concludes that continuity markers for world maps can be a useful part of map design that clarifies how the edges of a world map fit together for children who have learned to use this tool.     

Filling Some Black Holes: Modeling the Connection Between Urbanization,Infrastructure, and Global Service Intensity

This empirical article combines insights from previous research on the level of knowledge-intensive service in metropolitan areas with the aim to develop an understanding of the spatial structure of the global service economy. We use a stepwise regression model with the Globalization and World Cities research network's measure of globalized service provisioning as the dependent variable and a range of variables focusing on population, infrastructure, urban primacy, and national regulation as independent variables. The discussion of the results focuses on model parameters as well as the meaning of outliers and is used to explore some avenues for future research.     

Transformations of the Spatial Hegemony of the Courtyard in Post-Soviet St. Petersburg

Abstract

The courtyard is a space that existed before, during, and now after the Soviet period in Russian urban history. Noting the change in the courtyard's formerly hegemonic position on daily trajectories illustrates both Harvey's and Lefebvre's suggestions for uncovering the way that spaces articulate social values. A particularly revealing case study occurs in the struggle over including courtyards in a Chinese developer's project for a new multi-use district outside St. Petersburg. A brief history of the courtyard in Soviet planning allows subsequent analysis of the ways in which the city administration, the Chinese design team, and Russian planners deployed the courtyard as a spatial code for social meaning in design discussions. Examining the change in function and conceptualization of the courtyard shows how different groups in post-Soviet Russia seek to retain or redeploy concepts of the “collective” as they attempt to remake St. Petersburg as a successful “world” city.     

Virtual Field Geologic Trip System

1IntroductionThe objective of developing Virtual Field Geo-logic Trip System (VFGTS)is for geologic educa-tion and research, 3D geologic information system. The key technique of VFGTS is scientific visualiza-tion. In a virtual geologic world users can have a geologic exploration, observation and research. The technique of visualization appeared in 1987. It is a technique of transforming the data gained by experiment or numerical calculation into the image which can be accepted…     

秦岭终南山地质遗迹全球对比及世界地质公园建立

秦岭中段终南山地区地质现象复杂,地质遗迹资源数量多、种类全,分布有典型地层剖面、岩浆活动遗迹、构造剖面及典型构造运动遗迹、地质地貌景观等多种类型地质遗迹。这些遗迹在环境、造山带和大陆动力学等研究方面有重要的科学意义,许多还具有景观价值。全球对比表明,区内多种地质遗迹具有独特性和垄断性。为保护好地质遗迹开展科研和旅游并兼顾生态保护,建立终南山世界地质公园是最佳选择。为此,划分出三级地质遗迹保护区及生态保护区,在保护区内设立若干特殊遗迹保护点,并提出相应管理措施。同时,作为大型地质公园,在分区开发保护的基础上,利用中应充分注意各种资源及各园区的有效整合问题。     

世界遗产地西湖的物理拥挤和心理拥挤关系

分析世界遗产地西湖各小景点的景观功能性差异和西湖申遗成功后主要收费景区客流的时空分布特征,梳理出4类观测点,分别测算出其物理拥挤度和心理拥挤度,探讨两者的关系以甄别中国国情下的旅游心理拥挤的关键性物理影响因子。得出结论：① 世界遗产地西湖的物理拥挤和心理拥挤的表征关系为一个近似的坐标轴的关系;② 遗产地西湖在拥挤管理上应实行分象限管理。③ 中国情境下,世界遗产地西湖的游客心理拥挤的主要物理影响因素为景区面积和景区引导标识系统。