The Lab: research news from UCR and the UC system

Courtesy of Steve Berardi
Courtesy of Steve Berardiele


Breakthrough in Hummingbird Research

It was always thought that the hummingbird’s flight generated a single trail of vortices that helped it fly. A vortex, or mass of whirling air, is created during the hummingbird’s downstroke. The wing movement causes an air pressure difference to develop and this creates flow from the bottom to the top of the wing.

Researchers from UC Riverside have discovered that there are two trails of vortices: one located under each wing per stroke when a hummingbird flies.

Professor Marko Princevac, Dr. Sam Pournazeri, Professor Douglas Altschuler and Paolo Segre are all researchers involved in the experiment. They published a paper for their research online last month in the journal entitled Experiments and Fluids.

The study was initiated because it would allow researchers to observe the effects of different types of wings from different flight speeds. “The conclusions from this study can be a great help in aerospace industry, especially in engineering design of unmanned vehicles used for medical surveillance,” said Pournazeri.

To observe the wing movements of the hummingbird, the team used high speed image sequences of 500 frames per second. The hummingbird flew in a white plume while hoverfeeding, which allowed the team to look at the wing movements from multiple perspectives. They also quantitatively analyzed the flow around the hummingbird using particle image velocimetry (PIV). This allowed the researchers to record the particles surrounding the birds and extract velocity fields.

These films showed the two vortices of downwards airflow under each wing. They also showed that each vortex loop was shed during each upstroke and downstroke. As such, “the hummingbird’s two wings form bilateral vortex loops during each wing stroke, which is advantageous for maneuverability,” according to Science Daily. The loops help the hummingbird overcome its weight and hover.

“This is another step in understanding now to maintain stability of flight.  From engineering perspective flying fast forward is relatively simple, but hovering and transition to hovering from forward flight can easily become unstable,” said Princevac.

FDA approves first bionic eye

The Department of Energy has announced the first ever retinal prosthesis or bionic eye to be approved by FDA. The project was a collaborative effort by UC Santa Cruz and four other universities. The artificial retina is called the Argus II Retinal Prosthesis and may prove to aid those inflicted with a chronic hereditary disease called retinitis pigmentosa. The ailment is characterized by gradual degeneration of the retina, which destroys the rods and cones in the eye.

The ultimate goal was to create a device that helped restore limited vision, specifically one that enabled reading, unaided mobility and facial recognition. “This implant enables patients to detect when lights are on or off, describe an object’s motion, count individual items, and locate objects in their environment,” reads the report on the artificial retina project. The bionic eye was a project built upon the work of Mark Humayun at USC and his breakthrough operation in 2002.

The Argus II project lasted 10 years and took up an investment of $75.2 million. It operates by using a miniature camera mounted in eyeglasses that captures images and wirelessly sends the information to a microprocessor, which is worn on a belt. This microprocessor then converts the data to an electronic signal and transmits it to a receiver on the eye. The pulses travel to the optic nerve and, ultimately, to the brain. The brain then perceives patterns of light and dark spots corresponding to the electrodes stimulated.

Funding for this project was provided by Department of Energy’s Office of Science and researchers from five of the nation’s DOE’s laboratories. The DOE Office of Science worked with private sector company Second Sight under the Cooperative Research and Development Agreement.

How to turn food waste into electricity

A housing development in UC Davis is planning to introduce a new source of renewable energy: a biodigester. UC Davis received federal funding for the project as a part of the Department of Energy’s Community Renewable Energy Development Project.

The biodigester turns organic waste into electricity. The waste is burned and produces biogas that a turbine converts into electricity.

The proposal aims to use food waste from dining halls and campus landscaping residue as raw material for the biodigester. They also want to use animal waste from the school’s animal facilities such as the veterinary college. UC Davis hopes biodigester will eliminate need to send waste to any landfills by 2020.

The campus’ housing development is called the UC Davis West Village and occupies 130 acres. Builders are hoping the student and faculty resident facilities will become “the largest net-zero energy use community in the nation—producing as much energy as it uses,” according the U.S. Department of Energy. To accomplish this, builders are focusing on ultra energy-efficient features, renewable energy from solar panels and potentially the biodigester.”

“So far, we are heading in the right direction in meeting our energy goals,” said Nolan Zail, Senior Vice President of Development for Carmel Partners—the private company developing the new campus residences.

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