News Article | April 17, 2017
A team of astronomers says they’ve caught wind of an atmosphere around a super-Earth known as GJ 1132b, just 39 light-years away. The findings, described in the Astronomical Journal, mark another step on the road to determining whether alien worlds near and far might be capable of hosting life. “It’s a great proof of concept that we can observe atmospheres on these small, rocky planets even from the ground,” said Laura Schaefer, a planetary scientist at Arizona State University who was not involved in the paper. “That’s really exciting and that means that we’ll be able to do it with more planets down the line as we find more planets of this size.” The planet, Gliese 1132b, was first spotted in 2015 orbiting a small, dim M dwarf (a type of red dwarf) star about one-quarter of the Sun’s radius. At the time, the discovery excited scientists even though — with a surface temperature of about 620 degrees Fahrenheit — the planet wasn’t considered habitable. “Receiving 19 times more stellar radiation than the Earth, the planet is too hot to be habitable but is cool enough to support a substantial atmosphere,” the authors of the 2015 study in Nature wrote. Because the host star was so close by, they added, “existing and upcoming telescopes will be able to observe the composition and dynamics of the planetary atmosphere.” Astronomers often try to find exoplanets using the transit method: They wait for a planet to cross in front of its star and measure how much starlight is blocked. It’s much easier to pick out gas giants akin to Jupiter than it is to pick out small, rocky planets because oversized gas giants cause more dramatic dips in the amount of starlight. Those few other exoplanets whose atmospheres have been studied are gas-giant planets or very large super-Earths, with something like eight times our planet’s mass. But because GJ 1132b is so close, and because its star is so small, the rocky planet blocks proportionally more light, making it easier to study. Gliese 1132b is interesting not just because it’s the first low-mass super-Earth to have a detectable atmosphere. It’s near Earth, putting it in the sights of existing telescopes; and it was also thought to be about 1.2 times the Earth’s radius, making it very close in size — and potentially composition — to our planetary home. For this paper, a team of European astronomers used the 2.2-meter ESO/MPG telescope in Chile to track nine of the planet’s transits in front of its star. They studied the starlight in seven different bands of light across optical and infrared wavelengths. As a planet passes in front of the star, it blocks a certain amount of starlight across all seven bands. But the small amount of starlight that passes through the atmosphere will be selectively filtered: Certain chemicals in the atmosphere will absorb (and thus, block) certain wavelengths while allowing others to pass straight through. The missing wavelengths can tell scientists which atoms and molecules are present. The astronomers found that, based on the amount of light blocked, the silhouetted planet has a radius about 1.4 times that of Earth, making it a little bigger than previously thought. GJ 1132b also appears larger in one of the infrared wavelength bands than it does in the rest — signaling the presence of an atmosphere that is transparent to some wavelengths but opaque to others. The researchers then modeled different scenarios, finding that the atmosphere could potentially be rich in water and methane. If that’s true, then it means the planet could have a steamy atmosphere and perhaps a magma ocean, said Schaefer, who cautioned that many more follow-up observations need to be done to ensure the vapor-filled atmosphere really is there. “It’s not confirmed that it’s water,” she pointed out. “So it’s very exciting but we definitely need more data on it.” Because M dwarfs are so abundant throughout the galaxy, and habitable-zone planets circling them are easier to find, many scientists think these dim stars may offer one of the best chances for finding a life-friendly world. But these red dwarfs are also thought to be much more active than main-sequence stars like the sun — with flares, eruptions and other activity that could blow a planet’s atmosphere away. Keep in mind, Gliese 1132b circles its star so closely that its “year” lasts just 1.6 Earth days. So if the planet does turn out to have an atmosphere in spite of that proximity, it would be good news for astronomers — because it would mean that M dwarfs are more stable places for habitable planets than thought. For now, researchers are somewhat limited in what they can probe with existing ground and space telescopes. But with the launch of NASA’s Transiting Exoplanet Survey Satellite (TESS) later this year and the James Webb Space Telescope in 2018, researchers may soon be able to find more interesting nearby targets and then probe their atmospheric composition with precision. Follow @aminawrite on Twitter for more science news and "like" Los Angeles Times Science & Health on Facebook. Why would beetles want to look, act and smell like army ants? To eat them, of course New view of dinosaurs could radically reshape their family tree Ancient relative of crabs, shrimps and lobsters is named in honor of David Attenborough
News Article | May 1, 2017
Noting how, "The search for life in the Universe has been transformed from speculation to a data-driven science," speakers like Stanford physicist Peter Michelson offered detailed plans for finding life on exoplanets. Over the course of two days on April 20-21, dozens of scientists attending the Breakthrough Discuss Conference contemplated options for exploring planets in other star systems. These option included using a new generation of powerful telescopes for long distance observations, as well as advancing a first-of-its-kind technology to visit other star systems—all within the next generation. What these strategies had in common was a focus on observing habitable zone planets in our local stellar neighborhood. In this neighborhood alone, within 30 light-years or so of our solar system, astrobiologists have already identified several Earth-like exoplanets and dozens of systems that may harbor Earth-like worlds. These exoplanets, identified by the effect they have on their parent star, are rocky and roughly the same size and density as Earth. They orbit their stars at a distance that would allow liquid water to exist on the surface. There is, however, at least one major difference between our planet and these potentially-habitable exoplanets. That is, they aren't circling stars like our sun. On the spectrum of stars, our sun is what's know as a yellow dwarf. It's bright, and not terribly large compared to the largest stars in our galaxy. Yet, even middling stars like our Sun aren't all that common. Our local stellar neighborhood -— and probably in the Universe as a whole -— is filled with many more low-mass stars. There are 20 yellow dwarf stars like our sun nearby and 250 M-dwarfs, a variety of star so small and dim that, despite their abundance, can't be seen with the naked eye. Over the last three-to-four years, every single low-mass star we've studied appears to have at least one planet. Usually, they have more than one. "How common are planets orbiting low-mass stars? Very common indeed," explained Courtney Dressing, an astronomer at UC Berkeley to the assembled group. "For a typical M-Dwarf, there tends to be 2.5 planets. One-in-four of the stars has a planet the same size and temperature as Earth in the habitable zone." Dressing's point was that given the number of M-dwarfs in the local region, there should be at least 60 potentially Earth-like planets in habitable zones within 32 or so light-years from here, and perhaps many more. To date, most of our exoplanet data comes from the Kepler spacecraft. The Kepler spacecraft has focused its search for planets on large M-dwarf stars. In the near future, when the small and medium-sized M-dwarfs are studied, we may discover that closer to one-in-three stars have an Earth-like planet in the habitable zone. Apart from just being more abundant, studying the potentially-habitable exoplanets around these low mass stars comes with other advantages. These exoplanets have tight orbits around their stars because the habitable zones are close in, giving scientists opportunities to view their transits every few weeks. It is during these transits, when the exoplanets pass in front of their stars, that we have the best opportunity to study their atmospheres for signs of life. Many conference attendees, including Mercedes López-Morales from the Harvard Center for Astrophysics, explained how we will be surveying the atmospheres of the closest habitable zone planets for signs of life dwelling on the surface or in an ocean. "We're going to look for oxygen," she said. Because the rise of oxygen in Earth's atmosphere corresponded with the appearance of life, we frequently use that particular molecule as a marker for the presence of life elsewhere. Also, oxygen likes to interact with other chemicals. If we discover a planet where oxygen is still hanging around in the atmosphere, something, possibly life, is actively making it. So, the search for life will focus on elements and molecules like hydrogen, oxygen, and methane. However, as López-Morales explained, there is a downside to this approach. "A planet's atmosphere is only 1 percent the size of the planet. The size of the signal is tiny. You need to collect at least one trillion photons to be very certain that you are truly looking at oxygen." The good news is that a new generation of telescopes designed for planetary exploration and astrobiology will be coming online to help us gather those photons. Around this time next year, the Transiting Exoplanet Survey Satellite (TESS) will be readying for launch. During its two-year mission, TESS will survey 200,000 stars, including the brighter ones in our local systems. The Giant Magellan Telescope (GMT) in Chile, slated to be operational by 2022, will have a resolving power 10 times greater than the Hubble Space Telescope. The GMT will feature a device called the G-CLEF spectrograph, which will be able to see molecules like oxygen in far-off planetary atmospheres. Finally, when the Extremely Large Telescope (ELT) opens in 2024, it will have more light-gathering-power than of Earth's current 8 to 10 meter telescopes combined. Astrobiologists are counting on these large telescopes coming online between now and 2024 to identify the prime candidates to look for oxygen and life in our stellar neighborhood. Even as we anticipate a treasure trove of atmospheric data from these missions, scientists are discovering species that live quite happily without oxygen, light, and other features that we used to believe were required for life. These discoveries highlight how atmospheric bio-signatures like oxygen are an imperfect, if tantalizing, way to look for life from afar. The question then becomes: Could there be there another way to look for extraterrestrial life beyond studying exoplanet atmospheres? Ideally, to definitively identify life on other worlds, we would visit nearby planets like Proxima b, only 4 light-years away, either in person or with a spacecraft. This is the goal of the Breakthrough's Starshot initiative. Announced a little more than a year ago, Starshot's goal, according to its founder, is to "literally reach the stars in our lifetimes." The plan to accomplish this feat involves launching a fleet of very small spacecraft. Starshot will then accelerate those craft to as close to lightspeed as possible. By aiming high-powered lasers at these gram-sized cameras in space we may be able to cut down the time, cost, and weight required to gain an up- close look at planets around other stars. "The goal is to fly a probe very close to a planet and figure out if it has life," said Avi Loeb, a physicist at the Harvard Smithsonian Center for Astrophysics. "What is the color of the planet? Is it green? Does it have vegetation? Is it blue, are there oceans? Or is it desert-like?" At the conference, NASA engineer Ruslan Belikov premiered simulations of what an exoplanet might look like from Starshot's point of view. Even if the craft were moving at 90 percent the speed of light, the onboard cameras should still be able to pick up signs of large oceans, clouds, and land masses that an exoplanet might have. The hope is that someday, by combining laser acceleration of these very small craft with cameras and other sensors, we might finally be able to take a firsthand look at habitable-zone-planets circling nearby stars, and in doing, perhaps definitively find life elsewhere in the Universe. Combining data from our new generation of very large telescopes with atmospheric observations of nearby exoplanets around M-dwarfs may help us choose the best targets for small Starshot craft flyby. "We are going to be the generation that is remembered for finding exoplanets. That's a fact," said López-Morales. "Are we going to be also the generation that will be remembered as the first ones who found life on those planets?" That, indeed, would be the breakthrough of a lifetime. Explore further: The space weather forecast for Proxima Centauri B
News Article | April 25, 2017
HUNT VALLEY, Md.--(BUSINESS WIRE)--TESSCO Technologies Incorporated (Nasdaq: TESS), a consultative provider of the end-to-end wireless solutions to deploy network and connectivity systems, will report financial results for its fiscal fourth quarter ended March 26, 2017 after the market closes on Monday, May 8, 2017. Management will host a conference call to discuss these results the following day, May 9, at 8:30 a.m. ET. To participate in the conference call, please call 855-319-5921 (domestic
Deng Y.-S.,Beijing Jiaotong University |
Xia H.,Beijing Jiaotong University |
Zenda Y.,TESS Co. |
Inoue H.,TESS Co. |
Qi L.,TESS Co.
Gongcheng Lixue/Engineering Mechanics | Year: 2011
Ladder track is a new type of vibration-reduction track system that has been applied to several urban railways in China. A series of experiments were carried out on the ladder track installed on the trial section of an elevated bridge on the Beijing Metro Line 5. The vibration transmission behaviours of the track were tested in the lab. The track irregularities were measured and the dynamic responses were measured of rails, sleepers and bridge deck when the train running on the ladder track and the common non-ballasted slab track. The data were analyzed in the time domain and the frequency domain. The experimental results show that: compared with common non-ballasted track, the ladder track has good vibration reduction characteristics.
Sogabe M.,Structure Mechanics Laboratory |
Asanuma K.,TESS Co. |
Nakamura T.,Track Structures and Geotechnology Laboratory |
Kataoka H.,Track Structures and Geotechnology Laboratory |
And 2 more authors.
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2013
Research has been carried out on the safety of ballasted track with a view to minimizing damage during earthquakes. There remains however a lack of insight into the dynamic behavior of ballasted track itself during earthquakes. Consequently the authors of this paper first carried out static analyses to evaluate stability of straight track resistance to buckling when using continuous welded rails. Secondly the authors carried out dynamic analyses of ballasted track behavior laid directly on the ground or on a structure, under earthquake conditions, based on parameters such as lateral peak resistance of ballast and scale of earthquake, inter alia.
Handa and Tess Co. | Date: 2014-02-26
A three-wheel pedal-style wheelchair which includes a roller at a side, close to the ground, of the wheelchair, wherein the roller prevents the wheelchair from turning over, a steering wheel arranged at a side of the wheelchair, and two front wheels respectively arranged at two opposite sides of the wheelchair, wherein the two front wheels comprises a driving wheel led to rotate forward or backward by a user stepping and a loose wheel, wherein when the wheelchair turns to a direction in a small radius, the steering wheel is considerably rotated to a direction and the driving wheel is rotated forward, wherein when the wheelchair turns to another direction, the steering wheel is considerably rotated to a direction and the driving wheel is rotated backward. Accordingly, the wheelchair is easily controlled to have a small turn, like whirling in one spot, to move and to turn safely.
Xia H.,Beijing Jiaotong University |
Xia H.,Catholic University of Leuven |
Deng Y.,Beijing Jiaotong University |
Deng Y.,Catholic University of Leuven |
And 6 more authors.
Structural Engineering and Mechanics | Year: 2013
As a new type of vibration reduction, the ladder track system has been successfully used in engineering. In this paper, a numerical model of the train-track-viaduct system is established to study the dynamic responses of an elevated bridge with ladder track. The system is composed of a vehicle submodel, a track submodel and a bridge submodel, with the measured track irregularities as the system self-excitation. The whole time histories of a train running through an elevated bridge with 3×27m continuous PC box girders are simulated. The dynamic responses of the bridge such as deflections, lateral and vertical accelerations, and the vehicle responses such as derailment factors, offload factors and car-body accelerations are calculated. The calculated results are partly validated through the comparison with the experimental data. Compared to the common slab track, adapting the ladder sleeper can effectively reduce the accelerations of the bridge girder, and also reduce the car-body accelerations and offload factors of the train vehicle. © 2013 Techno-Press, Ltd.
PubMed | Tohoku University and TESS Co.
Type: | Journal: Journal of medical engineering | Year: 2016
Clinical studies on application of functional electrical stimulation (FES) to motor rehabilitation have been increasing. However, muscle fatigue appears early in the course of repetitive movement production training by FES. Although M-wave variables were suggested to be reliable indices of muscle fatigue in long lasting constant electrical stimulation under the isometric condition, the ability of M-wave needs more studies under intermittent stimulation condition, because the intervals between electrical stimulations help recovery of muscle activation level. In this paper, M-waves elicited by double pulses were examined in muscle fatigue evaluation during repetitive movements considering rehabilitation training with surface electrical stimulation. M-waves were measured under the two conditions of repetitive stimulation: knee extension force production under the isometric condition and the dynamic movement condition by knee joint angle control. Amplitude of M-wave elicited by the 2nd pulse of a double pulse decreased during muscle fatigue in both measurement conditions, while the change in M-waves elicited by single pulses in a stimulation burst was not relevant to muscle fatigue in repeated activation with stimulation interval of 1 s. Fatigue index obtained from M-waves elicited by 2nd pulses was suggested to provide good estimation of muscle fatigue during repetitive movements with FES.