15,570 research outputs found

    High-Torque-Density Low-Cost Magnetic Gear Utilizing Hybrid Magnets and Advanced Materials

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    Two major challenges of existing high-performance magnetic gears are: (i) High content of rare-earth permanent magnets which results in high cost as well as price fluctuation; (ii) Conflict between mechanical and electromagnetic performances, especially in the design of highspeed rotor. A magnetic gear using a blend of magnet types, i.e NdFeB, or Dy-free NdFeB and ferrites, is proposed in this paper. The goal is to bring down the cost while retaining comparable torque-transducing performance to a baseline magnetic gear only using rare-earth NdFeB magnets. A variety of topologies based on different combinations of magnet types and geometric shapes have been studied and compared. In addition, the potential impact of using an advanced dual-phase material is evaluated. The goal is to eliminate the well-known tradeoff between rotor mechanical integrity and PM flux leakage

    Alan Sked’s case for Brexit: a six-point rebuttal

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    Shortly before the referendum, Alan Sked delivered a lecture at the LSE arguing that Britain should leave the EU. Ali M El-Agraa rebuts several of his key points

    Improving solar gain control strategies in residential buildings located in a hot climate (Tripoli-Libya)

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    A large number of recently-built residential buildings in Libya provide a poor quality indoor environment or require a huge amount of energy to run the air conditioning, therefore influencing the thermal comfort, energy consumption and carbon emissions. As the use of energy in buildings is the major contributor to air pollution and global climate change, improving energy efficiency through the application of bioclimatic design principles in residential buildings in Libya is a critical factor in reducing energy consumption, securing thermal comfort, and hence is an effective policy for reducing the environmental impacts such as global warming and ozone layer depletion. This research assumes that the use of appropriate orientation, materials and building configuration would offer suitable solutions for energy and environmental problems in hot, arid countries. This hypothesis is examined through an example located in Libya. A domestic building in Libya was studied with a view to reducing its energy consumption. The study included detailed monitoring for 45 days continuously, followed by computer simulation of a range of intervention strategies. A field study including temperature, humidity and electricity consumption measurements was carried out and results from the study were gathered and analysed. Moreover a computer simulation model was built using IES software, a fully dynamic simulation model to investigate the potential influence of changes to the building. The thermal comfort of users in a residential building in Tripoli, Libya was investigated. Field measurements and subjective environmental perception survey were used. It was established that building design in hot arid regions must consider thermal requirements
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