Most materials are capable of being only one thing at a time, but a team of engineers and physicists at the University of Wisconsin–Madison have now created an entirely new material in which completely contradictory properties can coexist. The compound is a polar metal. "Polar metals should not be possible," says Chang-Beom Eom, the professor of materials science and engineering (pictured here). Undeterred by the laws of the universe, Eom and his team created a compound that is a scientific oxymoron. Through a new synthesis approach supported by computational modeling, the group made a crystal with multiple personalities: part polar, part metallic. Metals conduct electricity because electrons flow freely throughout them. Polar materials, by contrast, impede the free flow of electrons and work as electrical insulators. The team needed to find something that can demonstrate both insulating and conducting properties. First, they separated the polar and metallic parts of the crystal. Some electrons gave rise to the metallic nature, moving within the material to conduct electricity. Other electrons contributed to the polar properties. However, because the natural molecular structure of the material is symmetrical, even after separating the two components, the material as a whole would not act polar. Equal and opposite arrangements of electrons canceled each other out. To overcome this obstacle, the researchers synthesized the substance with slightly off-kilter atoms, which threw off the internal symmetry enough to make the material polar. "The initial calculations that the theory suggested did not show the polar nature so we experimentally tested the materials, then went back and improved the models," says Eom. "We looped between theory and experiments, but most importantly, we actually created the material, demonstrated its polar and metallic properties, and developed an understanding of how this is happening." Ultimately, the polar metal was made by painstakingly growing thin films of material one atom at a time. Crucially, the substance was grown on top of a supporting lattice with a slightly offset molecular organization. Tightly clamping the growing film to this support skewed the internal arrangement of the material, stabilizing its internal geometry in the asymmetrical orientation necessary to maintain polarity. Synthesizing and characterizing this first-of-its-kind material required patience and precision. Researchers counted every atom deposited on the surface, as the substance slowly grew one layer at a time. They then used multiple complex optical and electronic and structural measurements to determine its properties. Their approach is an attempt to accelerate the discovery of multifunctional materials with unusual coexisting properties, paving the way to devices with the ability to perform simultaneous electrical, magnetic and optical functions. "This has been a complex effort, and theoretical and experimental contributions from all collaboration members has been essential. The project would not succeed otherwise," says Eom. This work was supported by the National Science Foundation under the Designed Materials to Revolutionize and Engineer our Future program, the U.S. Department of Energy Office of Basic Energy Sciences, and the Army Research Office. Eom's team blends theorists and experimentalists, including UW-Madison physics Professor Mark Rzchowski and James Rondinelli of Northwestern University, Venkatraman Gopalan of Penn State, Xiaoqing Pan of University of California, Irvine, Craig Fennie of Cornell University and Hua Zhou, Phillip Ryan, Yongseong Choi and Jong-Woo Kim of Argonne National Laboratory.
The idea that we can learn about possible extraterrestrial (ETI) communication systems by studying non-human communications on Earth is similar to the astrobiological idea that one might learn more about exobiology by studying the extremes of life on Earth. Such study was taken up by Dr. Brenda McCowan of University of California, at Davis, Dr. Laurance R. Doyle of the SETI Institute, and their PhD student at the time, the now Dr. Sean F. Hanser. Early work was also helped on by Dr. Jon M. Jenkins also of the SETI Institute at the time. To begin this study, we selected terrestrial species that are socially complex, but largely depend on acoustic signaling to communicate – that is, bottlenose dolphins and humpback whales. We also included squirrel monkeys. The tools we chose to apply were signal classification methods (largely the K-means cluster 60-point contour) and the broad mathematics of Information Theory discovered by Dr. Claude Shannon of Bell Laboratory in the late 1940s. Originally developed to ascertain the amount of information going through telephone lines, we applied it to quantify the amount of information, in bits, that was being communicated between captive, adult bottlenose dolphins. A linguistic relationship known as "Zipf's Law" appears to be a necessary but not sufficient condition for complex communications. In this relationship, the (base ten logarithm) of the frequency of occurrence of the various signal types (assumed to be sufficiently sampled so it can represent a probability) is plotted in logarithmic rank order, and a complex communication system will always give a -1 slope for the distribution of the signals types (letters, words, or phonemes). Although Zipf's Law applies to many systems, a communication system that is not coded must have this distribution to have the potential for complex relationships between the signals. In human languages we would call this "syntax" in the sense of rules of spelling and grammar. We discovered that adult bottlenose dolphins obey this Zipf's Law relationship so that there could exist "syntax" within their communication system. Why would such syntax exist? For one thing, this syntax enables the recovery of errors in the transmission, which definitely has survival value. A human example might be the recovery of missing letters in a poorly copied manuscript by the use of spelling rules. We also found that bottlenose dolphin communication follows a Zipf's Law distribution of signals. On the other hand, human babies do not follow a Zipf's Law distribution to their signals and, interestingly, baby bottlenose dolphins also do not follow a Zipf's Law distribution, rather they follow the same distribution that human babies follow. In other words, baby bottlenose dolphins "babble" their whistle language. By the time they are 2 years old, they have acquired the -1 slope adult language and start to whistle like adults. We have also applied Zipf's Law to stellar sources such as pulsars, and their signals do not obey Zipf's Law. We have then gone on to apply Shannon Information Entropy to humpback whales, and we discovered that they have enough "syntax" to recover mutual communications that have lost up to 40% of their signal content (in this case due to boat noise). This defines their language as intelligent communication, one that has many "rules" interconnecting the signals of various types, thereby maximizing error recovery. Thus, looking upward, this gives us a very simple first tool (of several more we have developed) that can be used to distinguish a set of signals that may be received from an extraterrestrial source as to whether it is a message of a complex communication system or not. For an ETI signal, we would be measuring the degree of communication complexity. Such algorithms may be used to broaden the search for extraterrestrial intelligence (SETI) by supplying mathematical tools of information theory, tested upon terrestrial non-human communication systems, to examine the message content with a sort-of "intelligence filter," whereas, to date, only the narrow-band carrier signal has been examined. Explore further: Dolphins, aliens, and the search for intelligent life
News Article | June 16, 2016
They’re small but terrible. A new set of sophisticated mini-robots can run, climb, fly and even serve in search-and-rescue efforts. Size is key in today’s fast-paced, emergency-ridden world: mini-robots are much cheaper to make than the big boys and can be better deployed in risky situations than their larger counterparts, which could be hampered by limited mobility. Researchers from the Biomimetic Millisystems Lab of University of California, Berkeley — funded by the National Robotics Initiative of the National Science Foundation (NSF) — developed small micro-bots that reportedly cost just $10 to $100 and can operate on a one-time use, disposable rescue missions. “The lab works closely with biologists to develop models of function which can be tested on engineered and natural systems,” the UC Berkeley lab said on its website. “[Our] current research is centered on all-terrain crawling using nanostructured adhesives and bioinspired flight.” Inverse has provided a rundown of these mini-robots, three of which were launched in May, and with two taking off from 2015 designs. This mini-robot is 10 centimeters (3.9 inches) in length and can jump 2 meters (6.6 feet) high via its springboard legs akin to roaches’. After landing, its wings expand to get it back up and move along to its target location. This high-tech crawler can independently adjust its jumping prowess and speed in order to situate itself on top of or over different kinds of surfaces. Here, the dynamic duo of two six-legged millirobots crosses complex terrains. One gets its front legs up over a given step, while the other clings to the first robot through a string and then push it over the hump. The first robot serves as an anchor for its companion to pull itself up. This tiny machine can fold ribbon, thus origami, from a 2D plane into a 3D object — hardly impressive if one thinks about it, but proves useful when one considers that the ribbons could transform into the robots’ replacement parts and serve as a self-healing, self-repair mechanism someday. Think The Terminator. At just 54 grams (1.9 ounces) this mini-robot speeds along and lays claim to being the fastest of its kind considering its size. Take note of the insect-like legs — and make sure to not miss the cute little bugger. This autonomous robot with flapping wings takes off with the help of a separate roach robot. It boasts of “energy advantages over rotary and fixed wing fliers,” potentially allowing systems this small to carry heavier burdens. The researchers will coordinate with California Task Force 3 Urban Search and Rescue to find people stuck in collapsed buildings, according to the NSF. The mini-robots can also help detect sulfide leaks in oil refineries as well as assist in the event of a massive earthquake. The team is also paying attention to how easily the robots can be manufactured, although challenges like maneuvering effectively through small holes and obstacles remain present. © 2016 Tech Times, All rights reserved. Do not reproduce without permission.
Pion-Tonachini L.,of University of California |
Hsu S.-H.,Neural Inc. |
Makeig S.,INC of UCSD |
Jung T.-P.,SCCN INC |
Cauwenberghs G.,INC of UCSD
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS | Year: 2015
The Electroencephalogram (EEG) is a noninvasive functional brain activity recording method that shows promise for becoming a 3-D cortical imaging modality with high temporal resolution. Currently, most of the tools developed for EEG analysis focus mainly on offline processing. This study introduces and demonstrates the Real-time EEG Source-mapping Toolbox (REST), an extension to the widely distributed EEGLAB environment. REST allows blind source separation of EEG data in real-time using Online Recursive Independent Component Analysis (ORICA), plus near real-time localization of separated sources. Two source localization methods are available to fit equivalent current dipoles or estimate spatial source distributions of selected sources. Selected measures of raw EEG data or component activations (e.g. time series of the data, spectral changes over time, equivalent current dipoles, etc.) can be visualized in near real-time. Finally, this study demonstrates the accuracy and functionality of REST with data from two experiments and discusses some relevant applications. © 2015 IEEE.