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Creators/Authors contains: "Drake, David"

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  1. ; ; ; ; ; ; ; (, An Electrodynamic Wheel Maglev Vehicle with a Passive U-Guideway)
    This paper reports on the electromagnetic analysis and experimental testing of a newly invented six-degree of freedom electrodynamic wheel (EDW) magnetic levitation (maglev) vehicle that can stably levitate over a passive low-cost U-guideway. The U-guideway is composed of two sections of L-track aluminum sheet. Both a radial and an axial proof-of-principle EDW maglev vehicle has been built and experimentally tested. The EDW-maglev vehicle contains four one pole-pair diametric magnetized magnets that are driven using a low-cost motor and motor controller. No advanced controls are needed to provide basic stability. A 3-D transient finite element analysis model was used to study the 3-D forces created when the magnets are rotated over the aluminum L-track. The track design study showed that in addition to providing lateral recentering force the L-track can also be used to increases thrust and lift force. 
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  2. ; ; ; ; ; ; ; ; (, Urban Ecosystems)
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  3. ; ; ; ; ; ; ; ; ; ; et al (, Science)
    COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable with no change in average movements or road avoidance behavior, likely due to variable lockdown conditions. However, under strict lockdowns 10-day 95th percentile displacements increased by 73%, suggesting increased landscape permeability. Animals’ 1-hour 95th percentile displacements declined by 12% and animals were 36% closer to roads in areas of high human footprint, indicating reduced avoidance during lockdowns. Overall, lockdowns rapidly altered some spatial behaviors, highlighting variable but substantial impacts of human mobility on wildlife worldwide. 
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