Compaction Bands in Sandstone are Permeable
José E. Andrade, Associate Professor of Civil and Mechanical Engineering, and colleagues have analyzed X-ray images of Aztec sandstone and revealed that compaction bands are actually more permeable than earlier models indicated. Their paper provides the first permeability calculations based on actual rock samples taken directly from the field in the Valley of Fire, Nevada. They conclude that these formations are not as impermeable as previously believed, and that therefore their ability to trap fluids—like oil, gas, and CO2—should be measured based on 3D images taken from the field. [Caltech Press Release]
Largest Biochemical Circuit Built Out of Small Synthetic DNA Molecules
Lulu Qian, Senior Postdoctoral Scholar in Bioengineering, and colleagues including Erik Winfree, Professor of Computer Science, Computation and Neural Systems, and Bioengineering, have built the most complex biochemical circuit ever created from scratch made with DNA-based devices in a test tube that are analogous to the electronic transistors on a computer chip."We're trying to borrow the ideas that have had huge success in the electronic world, such as abstract representations of computing operations, programming languages, and compilers, and apply them to the biomolecular world," says Dr. Qian. [Caltech Press Release]
French Republic Knights Professor Ravichandran
G. Ravichandran, John E. Goode, Jr. Professor of Aerospace and Professor of Mechanical Engineering, and Director of the Graduate Aerospace Laboratories (GALCIT) has been selected to receive the Chevalier de l'ordre des Palmes Académiques, which is the Knight grade of the French Republic's Order of Academic Palms. Founded by Napoleon in 1808 to honor educators and scholars, this distinction recognizes eminent personalities who have made significant contributions to the development of French culture, science, and education.
Order of Academic Palms
Converting Heat into Electricity in Space and on Earth - High-Performance Bulk Thermoelectrics
Jeff Snyder, Faculty Associate in Applied Physics and Materials Science, and colleagues have developed a thermoelectric material that might be able to operate off nothing more than the heat of a car's exhaust. "You'll see applications wherever there's a solid-state advantage," Snyder predicts. "One example is the charging system. The electricity to keep your car's battery charged is generated by the alternator, a mechanical device driven by a rubber belt powered by the crankshaft. You've got friction, slippage, strain, internal resistance, wear and tear, and weight, in addition to the mechanical energy extracted to make the electricity. Just replacing that one subsystem with a thermoelectric solution could instantly improve a car's fuel efficiency by 10 percent." [Caltech Press Release]
Stimulating Electrode Array Assists Paraplegic Man to Stand and Move Legs Voluntarily
Joel W. Burdick, Professor of Mechanical Engineering and Bioengineering, and colleagues including Yu-Chong Tai, Professor of Electrical Engineering and Mechanical Engineering, have used a stimulating electrode array to assist a paralyzed man to stand, step on a treadmill with assistance, and, over time, to regain voluntary movements of his limbs. Using a combination of experimentation, computational models of the array and spinal cord, and machine-learning algorithms, Professor Burdick and his colleagues are now trying to optimize the stimulation pattern to achieve the best effects, and to improve the design of the electrode array. Further advances in the technology should lead to better control of the stepping and standing processes.