Slingshot spiders use their conical webs to launch themselves at high speeds to catch prey.We built a launching mechanism inspired by the slingshot spider.Our launch mechanisms comprise a steel structure with eye bolt...Slingshot spiders use their conical webs to launch themselves at high speeds to catch prey.We built a launching mechanism inspired by the slingshot spider.Our launch mechanisms comprise a steel structure with eye bolts to hold a conical web made from latex rubber tubing.We pull the web by a winch using a lever arm.A quick-release mechanism connects the web to the winch using a tough-grid paracord.When we release the quick-return mechanism,the projectile material consisting of a steel ball achieved an acceleration of 5107 m s^(-2) or 521 times gravity,and a speed of 66.41 m s^(-1).The power per unit mass and energy per unit mass of our prototype was one tenth and one fifth that of the spider’s web respectively.In particular,we found that web structure consisting multiple radial web elements reinforced with circumferential web elements provide enhanced stiffness;as a comparison our web had a stiffness of about eight times that of traditional slingshot with a single radial web element.Our results suggest that adapting designs from nature can lead to potentially superior performance of man-made contraptions.展开更多
In May 2011, the Prison Management Bureau of Sichuan Province in Southwest China held a conference in its capital city Chengdu to discuss the management of severely sick prisoners. Coordinating Management on Major Dis...In May 2011, the Prison Management Bureau of Sichuan Province in Southwest China held a conference in its capital city Chengdu to discuss the management of severely sick prisoners. Coordinating Management on Major Diseases of Sick Prisoners in Sichuan （Trial） was issued then, marking the start of an overall deployment.展开更多
文摘Slingshot spiders use their conical webs to launch themselves at high speeds to catch prey.We built a launching mechanism inspired by the slingshot spider.Our launch mechanisms comprise a steel structure with eye bolts to hold a conical web made from latex rubber tubing.We pull the web by a winch using a lever arm.A quick-release mechanism connects the web to the winch using a tough-grid paracord.When we release the quick-return mechanism,the projectile material consisting of a steel ball achieved an acceleration of 5107 m s^(-2) or 521 times gravity,and a speed of 66.41 m s^(-1).The power per unit mass and energy per unit mass of our prototype was one tenth and one fifth that of the spider’s web respectively.In particular,we found that web structure consisting multiple radial web elements reinforced with circumferential web elements provide enhanced stiffness;as a comparison our web had a stiffness of about eight times that of traditional slingshot with a single radial web element.Our results suggest that adapting designs from nature can lead to potentially superior performance of man-made contraptions.
文摘In May 2011, the Prison Management Bureau of Sichuan Province in Southwest China held a conference in its capital city Chengdu to discuss the management of severely sick prisoners. Coordinating Management on Major Diseases of Sick Prisoners in Sichuan （Trial） was issued then, marking the start of an overall deployment.
