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New Algorithm Helps Autonomous Vehicles Find Themselves, Summer or Winter

06-24-21

Without GPS, autonomous systems get lost easily. Now a new algorithm developed at Caltech allows autonomous systems to recognize where they are simply by looking at the terrain around them—and for the first time, the technology works regardless of seasonal changes to that terrain. The general process, known as visual terrain-relative navigation (VTRN), was first developed in the 1960s. By comparing nearby terrain to high-resolution satellite images, autonomous systems can locate themselves. The problem is that, in order for it to work, the current generation of VTRN requires that the terrain it is looking at closely matches the images in its database. To overcome this challenge, Anthony Fragoso, Lecturer in Aerospace; Staff Scientist, Connor Lee, Graduate student in Aerospace, Austin McCoy, Undergraduate, and Soon-Jo Chung, Bren Professor of Aerospace and Control and Dynamical Systems and research scientist at JPL, turned to deep learning and artificial intelligence (AI) to remove seasonal content that hinders current VTRN systems. [Caltech story]

Tags: research highlights GALCIT MCE CMS Soon-Jo Chung Anthony Fragoso Connor Lee Austin McCoy

Harnessing Sound for Health: A Conversation with Tim Colonius

06-18-21

When a person develops a kidney stone or a gall stone—hard accumulations of minerals and other compounds created by the body—they can experience a great deal of pain and discomfort. Lithotripsy is the practice of breaking gall or kidney stones into small pieces within the body using shockwaves produced by a machine called a lithotripter. A new form of lithotripsy has been under development with the help of Tim Colonius, Frank and Ora Lee Marble Professor of Mechanical Engineering. [Caltech story]

Tags: research highlights MCE Tim Colonius

A Swiss Army Knife for Genomic Data

04-05-21

A good way to find out what a cell is doing—whether it is growing out of control as in cancers, or is under the control of an invading virus, or is simply going about the routine business of a healthy cell—is to look at its gene expression. Lior Pachter, Bren Professor of Computational Biology and Computing and Mathematical Sciences, has developed a complex software tool that enables the processing of large sets of genomic data in about 30 minutes, using the computing power of an average laptop. Like a Swiss Army knife, the tool can be used in myriad ways for different biological needs, and will help ensure the reproducibility of scientific studies. "The interdisciplinarity of our team was crucial to conceiving of and executing this project," says Pachter. "There are people in the lab who are computer scientists, biologists, engineers. Sina Booeshaghi is in the mechanical engineering department and brings the perspective of his design background and engineering." [Caltech story]

Tags: research highlights MCE CMS Lior Pachter Sina Booeshaghi

Untangling the Heat Paradox Along Major Faults

03-12-21

Nadia Lapusta, Lawrence A. Hanson, Jr., Professor of Mechanical Engineering and Geophysics, and graduate student Valère Lambert, seek to explain the size of the forces acting on "mature faults"—long-lived faults along major plate boundaries like the San Andreas Fault in California—in an effort to better understand the physics that drive the major earthquakes that occur along them. Understanding the physics that govern major earthquakes on different types of faults will help generate more accurate forecasts for earthquake threats. "We have a lot of data from large earthquakes along subduction zones, but the last really major earthquakes along the San Andreas were the magnitude-7.9 Fort Tejon quake in 1857 and the magnitude-7.9 San Francisco Earthquake in 1906, both of them before the age of modern seismic networks," Lapusta says. [Nature article] [Caltech story]

Tags: research highlights MCE Nadia Lapusta Valère Lambert

Student-Led Moon Dust Shield Team Named Finalist in NASA Competition

02-16-21

As astronauts walk across the moon, land spacecraft on its surface, drive lunar rovers around, or complete other astronaut tasks, they kick up the dust, and that is a problem because it can cause premature wear on mechanical parts, damage to seals, and may pose a health risk for the people breathing it in. "The sun is shining directly on these particles and giving them an electric charge," says third-year Caltech undergraduate student Luis Pabon. "This causes it to stick to the astronaut's suit or to any sensors or cameras that you put out on the moon." The Caltech team's invention, named Habitat Orientable & Modular Electrodynamic Shield (HOMES), tackles the problem of moon dust entering a potential lunar habitat and wreaking havoc within. [Caltech story]

Tags: research highlights GALCIT MCE Luis Pabon

Titanium Atom That Exists in Two Places at Once in Crystal to Blame for Unusual Phenomenon

12-07-20

Crystals are usually good at conducting heat. By definition, their atomic structure is highly organized, which allows atomic vibrations—heat—to flow through them as a wave. Austin Minnich, Professor of Mechanical Engineering and Applied Physics, has discovered why a perfect crystal is not good at conducting heat, although it seemingly should be. "We have found that quantum mechanical effects can play a huge role in setting the thermal transport properties of materials even under familiar conditions like room temperature," says Austin Minnich. [Caltech story]

Tags: APhMS research highlights MCE KNI Austin Minnich

Robotics Engineers Take on COVID-19

11-18-20

Methods that were originally created to help robots to walk and autonomous cars to drive safely can also help epidemiologists predict the spread of the COVID-19 pandemic. Aaron Ames, Bren Professor of Mechanical and Civil Engineering and Control and Dynamical Systems, and colleagues took these tools and applied them to the development of an epidemiological methodology that accounts for human interventions (like mask mandates and stay-at-home orders). By utilizing the U.S. COVID-19 data from March through May, they were able to predict the infection wave during the summer to high accuracy. "This is the greatest health challenge to face our society in a generation at least. We all need to pitch in and help in any way we can," Ames says. [Caltech story]

Tags: research highlights MCE CMS IST Aaron Ames CDS Andrew Singletary

Lab-Grown Earthquakes Reveal the Frictional Forces Acting Beneath Our Feet

09-03-20

Simulating an earthquake on a miniature scale in a laboratory known unofficially as the "seismological wind tunnel," engineers and seismologists have produced the most comprehensive look to date at the complex physics of friction driving destructive thrust-fault earthquakes. "Simulating earthquakes in a lab lets us observe how these brief and violent events grow and evolve by ‘slowing down' their motion through high-speed photography and optics," says Ares Rosakis, the Theodore von Karman Professor of Aeronautics and Mechanical Engineering. [Caltech story]

Tags: research highlights GALCIT MCE Ares Rosakis

A Pathway to Longer-Lasting Lithium Batteries

08-06-20

The energy density of batteries have been a major challenge for consumer electronics, electric vehicles, and renewable energy sources. Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute, has made a discovery that could lead to lithium-ion batteries that are both safer and more powerful. Findings provide guidance for how lithium-ion batteries, one of the most common kinds of rechargeable batteries, can safely hold up to 50 percent more energy. "Every power-requiring application would benefit from batteries with lithium instead of graphite anodes because they can power so much more," says Greer. "Lithium is lightweight, it doesn't occupy much space, and it's tremendously energy dense." [Caltech story]

Tags: APhMS research highlights MCE Julia Greer KNI

Ari Rosner Develops Tool That Configures Socially-Distanced Students In Classrooms

07-31-20

Mechanical engineering student Ari Rosner, has developed an interactive Excel worksheet powered by advanced algorithms to help schools with social distancing in classrooms. Schools can plug a room’s dimensions and social distancing parameters into the worksheet, and the most efficient configuration of students for a designated classroom would automatically be mapped out. Rosner’s model situates students in rows or in a hexagonal pattern, depending on a room’s shape, in order to safely maximize space. "I cried when I saw how this worked," said Rachael Burton, the development director at a small private school in Brooklyn, New York. "I knew Ari’s mathematical chart could save our lives." [Forbes story]

Tags: research highlights MCE Ari Rosner