Inside Rensselaer
Volume 7, No. 4, March 1, 2013
   

Lemelson Finalists Named

Student innovations in earthquake protection devices for structures; brighter, smarter LEDs; and personalized medicine with implantable sensors are facing off to claim this year’s $30,000 Lemelson-Rensselaer Student Prize.

A public ceremony announcing this year’s winner will be held at 3:30 p.m. on Tuesday, March 5, in the auditorium of the Center for Biotechnology and Interdisciplinary Studies.

This year’s finalists are:
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NAVID ATTARY   MING MA   REBECCA WACHS
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NAVID ATTARY
Doctoral Student, Department of Civil and Environmental Engineering
Faculty Adviser: Michael Symans
“A Revolution in Earthquake Protection Devices: Rotation-Based Mechanical Adaptive Passive Device.”

MING MA
Doctoral Student, Department of
Materials Science and Engineering
Faculty Advisers: E. Fred Schubert and Linda Schadler
“Graded-refractive-index (GRIN) Structures for Brighter and Smarter Light-Emitting Diodes.”

REBECCA WACHS ’13
Department of Biomedical Engineering
Faculty Adviser: Eric Ledet
“Enabling Personalized Medicine Through an Elementary and Robust Implantable Sensor.”

Photos by Kris Qua

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Navid Attary has created a seismic protection device to boost the resiliency of bridges and buildings to earthquakes. His innovation, which uses a new and novel method to dissipate the destructive forces of earthquakes, could help save countless lives and prevent billions of dollars of damage around the world every year.

It is beyond humanity’s ability to prevent earthquakes, but structural and earthquake engineers throughout history have developed strategies for strengthening structures and reducing the damage dealt by earthquakes. For reducing damage, most seismic protection systems used today work by dissipating, or damping, the energy created by quakes. Passive dampers are not unlike shock absorbers in automobiles, and they usually feature a cylinder containing fluid and a piston that drives the fluid through the device. This helps redirect earthquake energy from the frame of the building or bridge to the damping device, which then harmlessly dissipates the energy in the form of heat.

While reliable and long-lived, these passive dampers have limited effectiveness because they cannot adapt to each earthquake’s unique movement patterns. Active dampers are smarter and able to respond to many different types of movement, but these electronic devices are expensive to maintain, and cease to function if power is lost during an earthquake.

Attary’s solution to this problem was to create a new type of seismic protection device that adapts to different types of movement, but requires no electricity and no expensive maintenance. He invented a rotation-based mechanical adaptive passive device, or RB-MAP, which is comprised of a meticulously engineered collection of gears, pre-torqued springs, and damping devices that can be installed underneath a bridge or inside the wall of a building.

Initial testing has shown that Attary’s RB-MAP can reduce the force in structures during earthquakes by up to 60 percent.
Ming Ma has developed a new method to manufacture light-emitting diodes (LEDs) that are brighter, more energy efficient, and have superior technical properties than those on the market today. His innovation holds the promise of hastening the widespread adoption of LEDs and reducing the overall cost, energy consumption, and environmental impact of illuminating our homes and businesses.

Over the past decade, there has been a profound shift in the way we light our homes, offices, and businesses. Conventional incandescent and fluorescent light sources are increasingly being replaced by more energy-efficient, longer-lived, and environmentally friendlier LEDs.

Improving the efficiency of LEDs and introducing new functionalities such as controllable light emission patterns are critical steps to continuing and accelerating their widespread adoption. One major challenge still needing to be solved is improving the low light-extraction efficiency of LEDs—or the percentage of produced light that actually escapes from the LED chip. Currently, most unprocessed LEDs have a light-extraction efficiency of only 25 percent, which means 75 percent of light produced gets trapped within the device itself.

Ma’s solution to this problem was to create an LED with well-structured features on the surface to minimize the amount of light that gets reflected back into the device, and thus boost the amount of light emitted. He invented a process for creating LEDs with many tiny star-shaped pillars on the surface. Each pillar is made up of five nanolayers specifically engineered to help “carry” the light out of the LED material and into the surrounding air.

Ma’s patent-pending technology, called GRIN (graded-refractive-index) LEDs, has demonstrated a light-extraction efficiency of 70 percent, meaning 70 percent of light escaped and only 30 percent was left trapped inside the device—a huge improvement over the 25 percent light-extraction efficiency of most of today’s unprocessed LEDs.
Rebecca Wachs has invented a new implantable sensor with the ability to wirelessly transmit data from the site of a knee replacement, spinal fusion, or other orthopedic surgery. Simple, robust, and inexpensive to make, her sensor holds the promise of advancing personalized medicine by giving doctors an unprecedented wealth of information about how an individual patient is healing.

Researchers have endeavored since the 1960s to extract information from sensors implanted in the body. Nearly all of the solutions, however, have been hampered by the requirement of complex electronics, antennas, frequent modifications to the implant, or the need for external power sources such as batteries. The devices end up being impractical and too expensive. Because of these limitations, surgeons today usually rely on X-rays or MRIs to monitor the progress of their patient’s recovery following an orthopedic procedure. Most diagnoses therefore rely on subjective observation instead of objective data.

Wachs’ patent-pending solution to this challenge was to create a simple, practical sensor to provide rich, objective data on which to make diagnoses about surgery sites. She invented a wireless sensor that needs no battery, no external power, and requires no electronics within the body. Instead, the sensor is powered by an external device, which is also used to capture the sensor data.

Measuring only 4 millimeters in diameter and 500 microns thick, the wireless sensors look like small coils of wire and are attached to commonly used orthopedic musculoskeletal implants such as rods, plates, or prostheses. Once in the body as part of the implant, the sensor can monitor and transmit data about the load, strain, pressure, or temperature of the healing surgery site. The sensor is scalable, tunable, and easy to configure so that it may be incorporated into many different types of implantable orthopedic devices.

This year marks the seventh annual $30,000 Lemelson-Rensselaer Student Prize competition, which is funded through a partnership with the Lemelson-MIT Program. For more information on the ceremony visit, www.eng.rpi.edu/lemelson.

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Inside Rensselaer
Volume 7, Number 4, March 1, 2013
Rensselaer Polytechnic Institute
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