Entries with tag university of sheffield.

Researchers Produce Airframe Quickly with 3D Printing

Scientists at the University of Sheffield’s Advanced Manufacturing Research Center have made a drone’s airframe using only 3D printing. This let them produce the airframe and have it flying within a day, and use less material in the process. The researchers made a blended-wing aircraft using fused deposition modeling, in which layers of a material are built up to make an object. Typically, the process requires additional material to support the structure during printing, which adds to the cost and construction time. The University of Sheffield scientists’ design eliminates the support material by changing the geometry of the design. Their design structure contains no critical angles that would require such support material. Their airframe has a 1.5-meter wingspan and weighs less than 2 kg without the motor and electronics. They are also designing a new version of the airframe that has a greater wing span and that will be able to fly longer and faster, and carry bigger payloads. (SlashDot)(Gizmag)(Advanced Manufacturing Research Center)

Poor Indoor Signals May Hamper 4G Adoption

As more mobile phone companies roll out 4G cellular services, which promise to give consumers 100 megabit per second connections, the technology’s signal strength and other transmission characteristics are under a microscope. Most providers base their performance metrics on transmissions between points outdoors. However, the technology doesn’t work well indoors because signals don’t transmit well, creating dead spots, say two UK academic researchers who studied the topic. “This means that the 4G rollout will not guarantee a better data-delivery experience for indoor customers who already experience a bad signal with 3G,” said University of Warwick assistant professor Weisi Guo, who worked with University of Sheffield research student Siyi Wang on the project. “And it’s not just indoor customers. Users standing outside in the shadow of buildings could also experience poor signal strengths. Unless nodes such as small cells are deployed to improve signal penetration to indoor areas, the performance improvement under poor signal conditions is small. … Regardless of what the mobile phone companies will tell you to sell you an upgrade, we are not as 4G ready as they would have you believe.” (PhysOrg)(The Conversation)
 

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