Microscopic Devices That Control Vibrations Could Allow Smaller Mobile Devices
12-12-18
Chiara Daraio, Professor of Mechanical Engineering and Applied Physics, and colleagues have developed phononic devices that include parts that vibrate extremely fast, moving back and forth up to tens of millions of times per second. The devices were developed by creating silicon nitride drums that are just 90 nanometers thick. The drums are arranged into grids, with different grid patterns having different properties. Professor Daraio, along with former Caltech postdoctoral scholar Jinwoong Cha, have shown that arrays of these drums can act as tunable filters for signals of different frequencies and can act like one-way valves for high-frequency waves. [Caltech story]
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Chiara Daraio
MCE
APh
postdocs
Jinwoong Cha
Nailing It: Caltech Engineers Help Show That InSight Lander Probe Can Hammer Itself Into Martian Soil
11-26-18
Professor José Andrade’s research team including Postdoctoral researchers Ivan Vlahinic and Jason Marshall have helped the InSight Mars lander boldly go where no one has gone before: beneath the surface of Mars. InSight is equipped with two main instrument packages: a seismometer for studying how seismic waves (for example, from marsquakes and meteorite impacts) travel through the planet and a "mole" that will burrow into the ground, dragging a tether with temperature sensors behind it to measure how temperatures change with depth on the planet. These instruments will tell scientists about Mars's interior structure (similar to the way an ultrasound lets doctors "see" inside a human body) and also about the heat flow from the planet's interior. When designing the mole the engineers at JPL wanted to be certain that it would be capable of reaching the necessary depth, and so they called on Professor Andrade, an expert on the physics of granular materials. He was able to develop new computer models that helped the JPL team predict the mole's effectiveness in Martian soil. Unless the mole encounters an obstacle, Andrade is confident that it will be successful. [Caltech story]
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MCE
Jose Andrade
postdocs
Ivan Vlahinic
Jason Marshall
Dragonfly Larvae Inspire New Designs for Prosthetic Heart Valves
07-17-18
Professor Mory Gharib and postdoctoral researcher Chris Roh (MS '13, PhD '17) have studied the design and control of the jets that dragonfly larvae use to propel themselves to re-design health values. "The current heart valve design is a one-size-fits-all, where no patient-specific design is considered, and this causes many post-transplant complications," Dr. Roh says. "We believe that an intentionally off-centered opening of the heart valve to more closely match the patient's original blood flow will be an important design parameter that can be adjusted based on each patient's heart morphology." [Caltech story]
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GALCIT
MedE
Morteza Gharib
Chris Roh
postdocs
No Motor, No Battery, No Problem
05-15-18
Chiara Daraio, Professor of Mechanical Engineering and Applied Physics, and colleagues have developed robots capable of self-propulsion without using any motors, servos, or power supply. Instead, these first-of-their-kind devices paddle through water as the material they are constructed from deforms with temperature changes. "Combining simple motions together, we were able to embed programming into the material to carry out a sequence of complex behaviors," says Caltech postdoctoral scholar Osama R. Bilal, who is co-first author of the PNAS paper is titled "Harnessing bistability for directional propulsion of soft, untethered robots." [Caltech story]
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Chiara Daraio
MCE
APh
postdocs
Osama Bilal
Solving Pieces of the Genetic Puzzle
05-09-18
Postdoctoral scholar Nathan Belliveau working in the laboratory of Professor Rob Phillips has applied a method called Sort-Seq to mutate small pieces of noncoding regions in E. coli and determined which regions contain binding sites. Binding sites are the locations where specialized proteins that are involved in transcription—the first step in the process of gene expression—attach to DNA. "Humans have such a wide variety of cells—muscle cells, neurons, photoreceptors, blood cells, to name a few," says Professor Phillips. "They all have the same DNA, so how do they each turn out so differently? The answer lies in the fact that genes can be regulated—turned on or off, dialed up and dialed down—differently in different tissues. Until now, there have been no general principles to help us understand how this regulation was encoded." [Caltech story]
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Rob Phillips
APh
postdocs
Nathan Belliveau
