© 2010 PhysOrg.com Citation: Giant sculptured Mayan head found (2010, January 27) retrieved 18 August 2019 from https://phys.org/news/2010-01-giant-sculptured-mayan.html Rare early Mayan portrait is found Archaeologists from the Polytechnic University of Valencia and the University of Valencia in Spain recently found the sculpture in the Chilonché ruins in the jungle-covered Petén region. The team are experts in stuccoed artifacts and their restoration and conservation. They have dated the giant head to the early Classical period of 300-600 AD, which is considerably older than other artifacts found at the site, and means the site is older than thought previously. The find is in excellent condition and some of its original colors have been preserved.One of the archaeology team, Professor Gaspar Muñoz Cosme, said the find was “spectacular” and the sculpture could be linked to Mayan mythology, and possibly represents an imaginary being such as a Mayan god, or an underworld figure. He said the discovery provides important scientific data that helps us understand the architecture of the Mayans of the time. The team hopes to find similar heads at the site, since the Mayans often built and arranged multiple items symmetrically.The Petén region is close to well-known Mayan cities such as Tikal and Nakum. It contains dozens of Mayan ruins, but the site at Chilonché has not been excavated to a great extent, largely because the thick jungle region is home to poachers, looters looking for artifacts to sell on the black market, and drug smugglers carrying cocaine to nearby Mexico. The giant head was found inside one of the tunnels built by looters at the site. As soon as the find was located, the archaeologists contacted Guatemalan authorities to ensure security around the site was tightened because of the significance of the find.The giant figurehead sculpture is similar to other sculptured heads found at Uaxactun, where they decorated a solar observatory. In the Classical period from 300 to 900 AD the Mayans built vast cities and towering pyramids in an extensive area of Central America from Mexico through Honduras, El Salvador, Guatemala and Belize. The reasons for the collapse of the Mayan civilization in the last century or so of the Classical period remain a mystery, but may have been linked to deforestation and resulting climate change and extended droughts and crop failures. Maya mask at the National Museum of Anthropology in Mexico City. Image: Wolfgang Sauber, via Wikipedia. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore further (PhysOrg.com) — A decorated Mayan head measuring three meters (10 feet) at the base and sculptured out of stucco has been unearthed in northern Guatemala, near the border with Mexico. The sculpture had been buried for centuries under the thick jungle, and its presence may suggest the site could have been part of a Mayan city.
First demonstration of new laser-driven accelerator technology To find out a team of researchers from the California Institute of Technology set up a laser that pulses very quickly for a very short period of time, exciting the electrons on the target, while at the same time also striking a photo cathode to create an electron pulse. As they describe in their report paper published in Science, the team has found that by timing the laser pulse, they can then effectively cause an interaction between the generated electrons and those in the electric field. And in so doing, they found that in some cases the introduction of the electrons caused an increase in energy, while at other times it caused a decrease.The reason for the increase or decrease has to do with the moment in time that the electrons enter the electric field. If the electron arrives just ahead of an electric wave, it can in essence ride that wave causing an overall increase in energy, whereas if it lands in a trough, it causes a loss, as energy is dissipated due to electrons colliding. In many respects the phenomenon seen here is very similar to what has been found in recent research with tsunamis. If a tsunami wave comes ashore at the same moment that a natural wave is also coming ashore, the result is a much bigger wave than if the tsunami wave arrives when a trough is heading ashore.The reason this is all exciting is because it means that it might be possible to change the way such things as solar arrays are used to collect energy, or how much heat is generated by computer chips. Also, as the team points out, it’s important because the underlying technology itself is a breakthrough of sorts in capturing high-speed events with very high precision which could help researchers in many fields, not just electronics. Explore further (PhysOrg.com) — Scientists have known for quite some time that when light strikes objects, electrons are excited causing a tiny bit of oscillation to occur that results in the creation of an electric field. They also know that the amount of oscillation differs between different types of materials; electrons in metals such as gold and silver, for example, tend to oscillate more than do electrons in other materials. But what hasn’t been well understood is what happens with electron oscillations in metals that are smaller than the wavelengths of light that are striking it. Citation: Researchers build a probe capable of capturing the motion of electrons in a nanoparticle (2012, January 6) retrieved 18 August 2019 from https://phys.org/news/2012-01-probe-capable-capturing-motion-electrons.html © 2011 PhysOrg.com Journal information: Science More information: Subparticle Ultrafast Spectrum Imaging in 4D Electron Microscopy, Science 6 January 2012: Vol. 335 no. 6064 pp. 59-64. DOI: 10.1126/science.1213504ABSTRACTSingle-particle imaging of structures has become a powerful methodology in nanoscience and molecular and cell biology. We report the development of subparticle imaging with space, time, and energy resolutions of nanometers, femtoseconds, and millielectron volts, respectively. By using scanning electron probes across optically excited nanoparticles and interfaces, we simultaneously constructed energy-time and space-time maps. Spectrum images were then obtained for the nanoscale dielectric fields, with the energy resolution set by the photon rather than the electron, as demonstrated here with two examples (silver nanoparticles and the metallic copper–vacuum interface). This development thus combines the high spatial resolution of electron microscopy with the high energy resolution of optical techniques and ultrafast temporal response, opening the door to various applications in elemental analysis as well as mapping of interfaces and plasmonics.PERSPECTIVE: Plasmonic Modes Revealed, Science 6 January 2012: Vol. 335 no. 6064 pp. 47-48. DOI: 10.1126/science.1215588AbstractWhen nanostructures made of metals such as gold and silver are illuminated with visible light, plasmonic modes can be excited that cause conduction electrons to oscillate. This motion creates a pattern of electric fields, extending both within and outside the structure, that can be tuned by changing the particle size and shape to efficiently couple light to electronic processes. Practical applications of this coupling include improved harvesting of light for photovoltaics (1) and enhanced sensitivity for sensors based on light-emitting messenger molecules (2). Although there is well-developed theoretical understanding of how photons interact with nanostructures that are much smaller than their wavelength, we have few methods for measuring electric fields nearby and within nanoscale structures during photonic excitation. On page 59 of this issue, Yurtsever et al. (3) report using time-resolved electron energy gain/loss spectroscopy in an electron microscope to obtain spatially resolved maps of electric fields that result when nanoscale metal objects are illuminated by incident photons. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Explore further A Virginia-based company, Kaprica Security, is set to introduce a smartphone scanner in the form of, all things, a charger. Skorpion, as the charger is named, will provide relatively easy protection because the device will scan for malware while the phone is powering up. The setup is no more complicated than plugging in Skorpion and plugging the phone into the charger. In doing so, Skorpion will scan for malware, viruses and malicious rootkits, The process consists of three basic parts, quick scan, deep scan, and a report of the results via the company’s web interface.The company has a slogan of “Being secure is as easy as charging your phone.” The product differentiation lies in the fact that it is physically separate from your smartphone, to raise the level of protection. The user gets to inspect the phone without having to rely on the phone for malware detection. Apps for catching malware may not succeed in identify the types that sit silently without the user aware that anything unusual is going on. With Skorpion, if malicious behavior is identified, the charger lights up with a red LED alert while its green light means no problems have been found. The company’s web interface identifies and reports on any malicious content and how “clean” the mobile device is. The interface keeps up with stats guides on what actions to take if the phone is compromised. Scan results can be shared with the user’s company IT department.According to a report in MIT Technology Review, Kaprica’s Skorpion will be co-branded with Belkin and will sell this year or early 2014. The charger will sell to enterprise customers for about $65. Customers paying monthly subscription fees of $3 to $4 will receive added features. Kaprica CEO Doug Britton was formerly a manager at Lockheed and focused on cyber-security research. Citation: Phone charger can place user on malware alert (2013, October 6) retrieved 18 August 2019 from https://phys.org/news/2013-10-charger-user-malware.html Credit: Kaprica Security Georgia Tech uncovers iOS security weaknesses More information: www.kapricasecurity.com/ (Phys.org) —More smartphones, more smartphone apps, and more busy smartphone users downloading apps have become attractive magnets for malware agents. A new category has grown up, not just general malware software but “mobile malware” and it continues to grow. Users have their own headaches when victimized and so do businesses. A sobering example of mobile malware surfaced this year at the Black Hat security event in August, where a Georgia Institute of Technology team showed how iPhones could be compromised with a charger, performing actions such as adding apps on the device without the user’s permission. Interestingly, if that put a whammy into people’s emotional feelings about phone chargers as a necessary evil, they may soon find themselves switching views in seeing chargers as a saving grace. © 2013 Phys.org This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
More information: Jérôme Crassous et al. Pressure-Dependent Friction on Granular Slopes Close to Avalanche, Physical Review Letters (2017). DOI: 10.1103/PhysRevLett.119.058003 A small team of researchers affiliated with several institutions in France has discovered why medium-sized ants have more trouble climbing out of sand pits than larger or smaller ants. In their paper published in the journal Physical Review Letters, the researchers describe experiments involving glass beads and metal disks and what they learned. Credit: CC0 Public Domain Explore further Antlions (also known as doodlebugs or lacewings) are insects that very strongly resemble dragonflies. They are known mostly for the predatory skills of their larvae, which look like small beetles—the larvae create sandpits by digging and pushing sand around. The pits take the shape of a bowl, which helps the larvae capture prey, usually ants. The ants walk into the pit, but are prevented by backsliding sand material from climbing back out. Eventually, they fall to the bottom of the pit, where the larvae wait for them.Intrigued by the antlion larvae and its pit, the researchers wondered about the specific factors that led to some ants becoming stuck in the pit while others escaped. Prior research had shown that the walls of the antlion pits were poised at a point just prior to an avalanche, which would, of course, make it more difficult for an ant to climb out. Any movement it made would cause tiny avalanches, preventing it from ascending the wall.To learn more, the researchers created artificial pits out of glass beads and mimicked ant activity by using metal disks covered with cardboard. They ran multiple tests to learn more about the conditions that led to the disks sliding into the bottom of the pit. The tests consisted of changing factors in the pit such as bead and disk size to assess the impact each had on disk friction and sliding.In looking at their results, the researchers found that the main factor leading to a disk sliding down into the pit was its mass—those that were very light did not dislodge beads, thus there were no small avalanches. Those that were large, on the other hand, hand enough mass to push some of the beads ahead of them as they began to slide, creating a dam of sorts, which caused the sliding to cease.The team then compared what they had found to the results of a prior study that involved learning which sorts of ants made it out of pits and which did not. That team had also found that it was medium-sized ants that wound up at the bottom of the pit. Trap-jaw ants jump with their jaws to escape the antlion’s den This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. © 2017 Phys.org Citation: Lab experiments show why medium-sized ants can’t crawl out of antlion larvae pits (2017, August 16) retrieved 18 August 2019 from https://phys.org/news/2017-08-lab-medium-sized-ants-antlion-larvae.html Journal information: Physical Review Letters
More information: Xin Ning et al. Mechanically active materials in three-dimensional mesostructures, Science Advances (2018). DOI: 10.1126/sciadv.aat8313 Diverse microarchitectures with integrated PZT microactuators. A) Bridge structure formed with two PZT microactuators. B) Fly structure with a pair of actuators on the wings. C) Tilted pyramid truss structure with three actuators. D) Four-leg table structure with an actuator on each leg. The accompanying contour plots show representative FEA modeling of the maximum principal strain in the electrodes and PZT microactuators. Credit: Science Advances, doi: 10.1126/sciadv.aat8313. © 2018 Phys.org In the study, the authors designed and assembled the 3-D mechanical mesostructures beginning with formation of 2-D precursor structures. The method integrated multiple functional materials via processes in microfabrication and transfer printing. The system comprised a photodefinable epoxy framework with patterned thin films of Pb(Zr0.52Ti0.48)O3 (PZT) as mechanical actuators and gold (Au) as electrodes and electrical interconnectors. Layers of polyimide (PI) encapsulated the system except in selected areas. These areas bonded the 3-D structure to the underlying elastomeric structure as contact sites for electrical probing. The authors used a mechanically guided process of compressive buckling to transform the 2-D precursor into a final 3-D architecture by releasing the pre-strain in the underlying elastomeric substrate. The optical and SEM images detailed the position of five independent PZT actuators; one at the center and four on the supporting legs. Microelectromechanical systems (MEMS) have expansive applications in biotechnology and advanced engineering with growing interest in materials science and engineering due to their potential in emerging systems. Existing techniques have enabled applications in cell mechanobiology, high-precision mass sensing, microfluidics and in energy harvesting. Projected technical implications broadly include constructing precision-sensing MEMS, tissue scaffolds that mimic the principles of mechanobiology, and energy-harvesting applications that can operate on supported broad bandwidths. At present, devices (microsensors and MEMS) are fabricated using manufacturing methods of the semiconductor industry—specifically, two-dimensional (2-D) lithographic etching—with mechanical and electric components in planar configuration. Extending the 2-D MEMS to the third dimension can allow broader applications and is an active area of ongoing research. Dynamic actuation is critically important in the design and development of bioMEMS, modulators and radiofrequency switches. Thin-film piezoelectric materials presently form the basis of actuators to produce fast switching at small driving voltages, in compact/lightweight configurations. The present focus in microscale mechanical engineering is to transfer such piezoelectric components into complex 3-D frameworks. In a recent study, Xin Ning and co-workers introduced strategies for the guided assembly and integration of heterogeneous materials to form complex 3-D microscale mechanical frameworks. The work combined multiple, independent piezoelectric thin-film actuators for vibratory excitation and precise control. To enable geometric transformation from 2-D to 3-D, the approach combined transfer printing as a scheme for materials integration, alongside structural buckling. The resulting designs on planar or curvilinear surfaces ranged from simple, symmetric layouts to complex hierarchical configurations. Experimental and computational studies systematically revealed underlying characteristics and capability of selectively exciting targeted vibrational modes that can simultaneously measure the viscosity and density of fluids. This offers significant potential for applications in biomedical engineering. Now published in Science Advances, the results serve as a foundation for an unusual class of mechanically active 3-D mesostructures with broad scope for advanced applications. The scientists used cutting-edge methods in transfer printing to integrate ultrathin piezoelectric films and ductile metals into polymer layers that were lithographically patterned into 2-D geometries. Controlled mechanical buckling transformed the 2-D multifunctional material structures into well-defined 3-D architectures. The 3-D mechanical responses were first modeled with finite element analysis (FEA) to select structural topologies and actuator locations to engineer controlled dynamics with displacements and distributions. 3-D printing the next generation of batteries Assembly of 3D active mesostructures via structural buckling. Credit: Science Advances, doi: 10.1126/sciadv.aat8313. The quantitative FEA conducted in the study served as a measure to optimize the locations of the PZT and metal layers, ensuring architectural integrity during compressive buckling. The predicted 3-D configuration agreed with the experimental observation. The schemes developed in the study to fabricate active mesostructures provided access to diverse classes of unique 3-D microscale architectures. Variations to the complex geometry layouts enabled the formation of unique 3-D microscale architectures. The microarchitectures included complex geometries resembling insects with wings and four legs, asymmetric 3-D geometries illustrated with a pyramid truss and a table structure. Each of these geometries were computed by FEA that excellently matched the experimental observation, demonstrating precision of the microfabrication process. Vibrational modes of the 3D geometries excited by strategically placed PZT microactuators. Credit: Science Advances, doi: 10.1126/sciadv.aat8313. Integrating 3D devices onto biomedical devices. A) A cardiovascular stent with three mesostructures corresponding to the tubes 1,2 and 3. B) the device can deform with the stent indicating robust adhesion suited for in vivo hemodynamic measurements. Credit: Science Advances, doi: 10.1126/sciadv.aat8313. The strategic 3-D designs created in the study introduced two qualitatively different and well-separated resonant modes to the mesostructures. Such resonant frequencies were able to decouple the sensitivities of viscosity and density of a fluid as two separate measurable quantities. The 3-D mesostructures optimized in the study were able to separately measure the viscosity and density of a variety of Newtonian fluids. This contrasted with conventional 2-D resonators that were sensitive to both viscosity and density parameters in a coupled manner, unable to precisely differentiate the two parameters therefore. Usually, to accurately measure high-frequency vibrations and quality factors in highly viscous fluids, sophisticated experimental apparatus such as doppler vibrometers or precisely calibrated strain sensors are used with their accompanying challenges, the 3-D mesostructures present a simpler method with high precision. Collective measurement capabilities of the 3-D structures indicated their broad utility to investigate complex fluids in healthcare and industry. Such 3-D structures can be integrated onto the surfaces of medical devices as inbuilt sensors due to their compliance. For instance, the authors recommend the integration of mesostructures on a cardiovascular stent (a device used to facilitate unconstructed blood flow in patients with atherosclerotic/deformed arteries) to precisely measure hemodynamics in the stent environment. Explore further The vibratory behavior of 3-D mesostructures excited by PZT microactuators were observed for all geometries designed in the study. The PZT microactuators were placed strategically in regions of interest on the 3-D geometries to control dynamic behavior and resonant modes. A representative 3D mesostructure with five independent PZT microactuators. A) Schematic illustration of the 2D architecture of the system. B) Illustration of the system in 3D after assembly by controlled biaxial compressive buckling. C) The expanded view of the layout. D) Optical images of the 3D architecture. E) Scanning electron microscopy (SEM) images of the top and perspective structure. The false color highlights the electrodes (gold) and microactuators (blue). F) Results of the finite element modeling with color representations showing the magnitude of strain. Credit: Science Advances, doi: 10.1126/sciadv.aat8313. Citation: Engineering 3-D mesostructures with mechanically active materials (2018, September 28) retrieved 18 August 2019 from https://phys.org/news/2018-09-d-mesostructures-mechanically-materials.html The capacity to integrate functional, high-performance piezoelectric materials into complex 3-D architectures for unusual classes of materials with active, high-precision and programmable function were demonstrated. The ubiquity of the materials integrated in the study can facilitate the development of 3-D MEMS and related technologies for advanced sensing applications within multidisciplinary fields. Journal information: Science Advances This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Kolkata: A rally was organized outside Tollygunge Metro station today to protest against an alleged moral policing incident inside a train compartment.According to the media reports, a man hugging his female friend raised eyebrows in a metro coach on Monday evening. A few people objected to the alleged intimacy, following which an argument ensued between the two sides.The mob then allegedly heckled the couple, pushed them out of the train and beat them up, the reports said. Also Read – Heavy rain hits traffic, flightsYouths gathered in large numbers outside Tollygunge Metro station this morning with placards and posters bearing slogans – “Hok alingan (let’s hug)”.”We are here to protest against the moral policing incident in metro. Our city is known as the city of joy and love. We have never witnessed such incidents before. It is completely shameful,” said a student of a renowned college in the city.Kolkata is known for its liberal mindset and it has no place for moral policing, he added. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedAnother student, who was part of the team that organised the demonstration, said they would offer free hugs inside the metro compartments today in protest against the incident.”A man and a woman hugging each other is no crime. It is a sign of affection, not perversion,” she said Indrani Banerjee, the spokesperson of the Metro Rail, said yesterday that appropriate action would be taken in the matter if the victims came forward with a complaint.The Metro Rail did not support moral policing of any kind, she had said.Photographs of the alleged assault have gone viral on the social media, sparking an outrage by authors, artists as well as common people.
Delhites recently got a glimpse of the gala spring festivities happening in Germany as the Indo-German Chamber of Commerce (IGCC) organised the third edition of German Springfest. The one day spring extravaganza was filled with food, fun and frolic activities for kids and adults.The German Springfest had an interesting array of products to showcase and people were seen splurging on clothes, jewellery, cosmetics, stationery, childrens’ products, home and garden accessories. There was a multi-cuisine food fiesta where people were seen relishing different delicacies. Also Read – ‘Playing Jojo was emotionally exhausting’Kids had a great time with lots of fun filled activities, art and craft workshops and segway rides. They were also enchanted by a juggling clown and were delighted to hear stories by the Kabuliwala in both German and Hindi. A live band performance in the evening added to the fun quotient with the guests dancing to its beats.The Indo-German Chamber of Commerce (IGCC) is renowned for the some of the biggest festivities happening year after year which includes the Oktoberfest and the German Christmas Market. “The ultimate aim of these fests is to make Delhites aware of the German Culture and also make the huge expat community in Delhi feel at home. We hope to be able to achieve both our aims with more and more events every year”, said Guido Christ, Deputy Director General, Indo-German Chamberof Commerce.
The trailer was released during the telecast of the India-Bangladesh match at the Cricket World Cup, after much buzz.Directed by Anurag Kashyap, the movie is set in the 1960s and is a large screen adaptation of Gyan Prakash’s Mumbai Fables. The story is about a man with big dreams and the extent he is willing to go to be successful. In the trailer, Ranbir is introduced as a street-fighter named Johnny Balraj with a curly mop of hair, embroiled in a cage-fight in soiled clothes with hands wrapped in bandages.On the other hand, Anushka Sharma, his love interest in the film, is Rosie, the star singer of a nightclub. The surprise package of the film’s trailer is filmmaker Karan Johar, who will be seen in as Kaizad Khambatta, a negative character.