Topic
Tower
About: Tower is a research topic. Over the lifetime, 18420 publications have been published within this topic receiving 82192 citations.
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Utrecht University1, University of Maryland, College Park2, Higher University of San Andrés3, Wageningen University and Research Centre4, University of St Andrews5, Royal Holloway, University of London6, Academy of Sciences of the Czech Republic7, Chinese Academy of Sciences8, University of Concepción9, University of Dayton10, Planetary Science Institute11, University of British Columbia12, Indian Institute of Science13, University of Maine14, International Centre for Integrated Mountain Development15, University of California, Los Angeles16, Johns Hopkins University17, University of Utah18, University of Zurich19, International Institute for Applied Systems Analysis20, Beijing Normal University21
TL;DR: The worldwide distribution and water supply of water towers (snowy or glacierized mountain ranges) is indexed, showing that the most important water towers are also the most vulnerable to socio-economic and climate-change stresses, with huge potential negative impacts on populations downstream.
Abstract: Mountains are the water towers of the world, supplying a substantial part of both natural and anthropogenic water demands1,2. They are highly sensitive and prone to climate change3,4, yet their importance and vulnerability have not been quantified at the global scale. Here we present a global water tower index (WTI), which ranks all water towers in terms of their water-supplying role and the downstream dependence of ecosystems and society. For each water tower, we assess its vulnerability related to water stress, governance, hydropolitical tension and future climatic and socio-economic changes. We conclude that the most important (highest WTI) water towers are also among the most vulnerable, and that climatic and socio-economic changes will affect them profoundly. This could negatively impact 1.9 billion people living in (0.3 billion) or directly downstream of (1.6 billion) mountainous areas. Immediate action is required to safeguard the future of the world’s most important and vulnerable water towers.
730 citations
TL;DR: The results of the ambient-vibration based investigations carried out to assess the structural conditions of a masonry bell-tower are presented in this paper, which is characterized by the presence of major cracks on the western and eastern loadbearing walls.
413 citations
01 Jul 2007
TL;DR: In this paper, a control algorithm for wind turbines mounted on floating platforms is presented, including the tuning method (pole-placement) to ensure the desired control frequency which provides stable tower vibration modes.
Abstract: Wind turbines mounted on floating platforms is subjected to completely different and soft foundation properties, than seen for onshore wind turbines. This leads to much lower natural frequencies, related to the rigid body motion of the structure which again leads to an unfavorable coupling between tower motion and the pitch control of the turbine. The tower motion in combination with the aerodynamics and the pitch control will be poor or even negative damped which causes large transient loads if not accounted for. The reason for this low damping is shown to be caused by a too fast pitch regulation compared to the motion of the tower or in other words the lowest control-structure natural frequency must be lower than the lowest critical tower frequency. A control algorithm is presented including the tuning method (pole-placement) to ensure the desired control frequency which provides stable tower vibration modes.
309 citations
TL;DR: In this article, the development of a mobile robot that can navigate overhead power transmission lines completely unattended by a human operator is described, and its ultimate purpose is to automate the inspection of power transmission line equipment.
Abstract: The development of a mobile robot that can navigate overhead power transmission lines completely unattended by a human operator is described. Its ultimate purpose is to automate the inspection of power transmission line equipment. The authors have assembled a full-scale functional model of such a mobile robot. Mechanical function testing of the robot has been performed, and results are reported. The robot navigates a ground wire that is located above the actual power transmission lines. It can maneuver over obstructions created by subsidiary equipment on the ground wire such as weights that prevent the wire from twisting and swinging. It is also equipped with an arc-shaped arm that acts as a guide rail and allows it to negotiate transmission towers. When the robot encounters a tower, it unfolds the arc-shaped arm and attaches it to the ground wire on opposite sides of the tower. It then travels along the arm to pass around to the other side of the tower. Once it is firmly affixed to the wire on the other side of the tower it detaches the arm and folds it up until it is needed again. >
293 citations
TL;DR: The Askervein Hill project as mentioned in this paper was a collaborative study of boundary-layer flow over low hills carried out under the auspices of the International Energy Agency Programme of R & D on Wind Energy Conversion Systems.
Abstract: The Askervein Hill project was a collaborative study of boundary-layer flow over low hills carried out under the auspices of the International Energy Agency Programme of R & D on Wind Energy Conversion Systems Two field experiments were conducted during September-October 1982 and 1983 on and around Askervein, a 116 m high hill on the west coast of the island of South Uist in the Outer Hebrides of Scotland During the experiments, over 50 towers were deployed and instrumented for wind measurements The majority were simple 10 m posts bearing cup anemometers but, in the 1983 study, two 50 m towers, a 30 m tower, a 16 m tower, and thirteen 10 m towers were instrumented for 3-component turbulence measurement The present paper provides an overview of the project as a whole, including details of the instrumentation and a summary of the data obtained Additional papers in the series, which are to appear in this journal
Subject to acceptable peer review
, will consider different aspects of the experimental data and related numerical-model and wind-tunnel studies
240 citations