Why a hydrogen economy doesnt make sense

first_imgIn a recent study, fuel cell expert Ulf Bossel explains that a hydrogen economy is a wasteful economy. The large amount of energy required to isolate hydrogen from natural compounds (water, natural gas, biomass), package the light gas by compression or liquefaction, transfer the energy carrier to the user, plus the energy lost when it is converted to useful electricity with fuel cells, leaves around 25% for practical use — an unacceptable value to run an economy in a sustainable future. Only niche applications like submarines and spacecraft might use hydrogen. “More energy is needed to isolate hydrogen from natural compounds than can ever be recovered from its use,” Bossel explains to PhysOrg.com. “Therefore, making the new chemical energy carrier form natural gas would not make sense, as it would increase the gas consumption and the emission of CO2. Instead, the dwindling fossil fuel reserves must be replaced by energy from renewable sources.”While scientists from around the world have been piecing together the technology, Bossel has taken a broader look at how realistic the use of hydrogen for carrying energy would be. His overall energy analysis of a hydrogen economy demonstrates that high energy losses inevitably resulting from the laws of physics mean that a hydrogen economy will never make sense. “The advantages of hydrogen praised by journalists (non-toxic, burns to water, abundance of hydrogen in the Universe, etc.) are misleading, because the production of hydrogen depends on the availability of energy and water, both of which are increasingly rare and may become political issues, as much as oil and natural gas are today,” says Bossel.“There is a lot of money in the field now,” he continues. “I think that it was a mistake to start with a ‘Presidential Initiative’ rather with a thorough analysis like this one. Huge sums of money were committed too soon, and now even good scientists prostitute themselves to obtain research money for their students or laboratories—otherwise, they risk being fired. But the laws of physics are eternal and cannot be changed with additional research, venture capital or majority votes.”Even though many scientists, including Bossel, predict that the technology to establish a hydrogen economy is within reach, its implementation will never make economic sense, Bossel argues. “In the market place, hydrogen would have to compete with its own source of energy, i.e. with (“green”) electricity from the grid,” he says. “For this reason, creating a new energy carrier is a no-win solution. We have to solve an energy problem not an energy carrier problem.”A wasteful processIn his study, Bossel analyzes a variety of methods for synthesizing, storing and delivering hydrogen, since no single method has yet proven superior. To start, hydrogen is not naturally occurring, but must be synthesized. Solar power system that works at night a renewable energy game-changer Citation: Why a hydrogen economy doesn’t make sense (2006, December 11) retrieved 18 August 2019 from https://phys.org/news/2006-12-hydrogen-economy-doesnt.html Explore furthercenter_img This chart compares the useful transport energy requirements for a vehicle powered from a hydrogen process (left) vs. electricity (right). Image Credit: Ulf Bossel. “Ultimately, hydrogen has to be made from renewable electricity by electrolysis of water in the beginning,” Bossel explains, “and then its energy content is converted back to electricity with fuel cells when it’s recombined with oxygen to water. Separating hydrogen from water by electrolysis requires massive amounts of electrical energy and substantial amounts of water.” Also, hydrogen is not a source of energy, but only a carrier of energy. As a carrier, it plays a role similar to that of water in a hydraulic heating system or electrons in a copper wire. When delivering hydrogen, whether by truck or pipeline, the energy costs are several times that for established energy carriers like natural gas or gasoline. Even the most efficient fuel cells cannot recover these losses, Bossel found. For comparison, the “wind-to-wheel” efficiency is at least three times greater for electric cars than for hydrogen fuel cell vehicles. Another headache is storage. When storing liquid hydrogen, some gas must be allowed to evaporate for safety reasons—meaning that after two weeks, a car would lose half of its fuel, even when not being driven. Also, Bossel found that the output-input efficiency cannot be much above 30%, while advanced batteries have a cycle efficiency of above 80%. In every situation, Bossel found, the energy input outweighs the energy delivered by a factor of three to four. “About four renewable power plants have to be erected to deliver the output of one plant to stationary or mobile consumers via hydrogen and fuel cells,” he writes. “Three of these plants generate energy to cover the parasitic losses of the hydrogen economy while only one of them is producing useful energy.”This fact, he shows, cannot be changed with improvements in technology. Rather, the one-quarter efficiency is based on necessary processes of a hydrogen economy and the properties of hydrogen itself, e.g. its low density and extremely low boiling point, which increase the energy cost of compression or liquefaction and the investment costs of storage. The alternative: An electron economyEconomically, the wasteful hydrogen process translates to electricity from hydrogen and fuel cells costing at least four times as much as electricity from the grid. In fact, electricity would be much more efficiently used if it were sent directly to the appliances instead. If the original electricity could be directly supplied by wires, as much as 90% could be used in applications.“The two key issues of a secure and sustainable energy future are harvesting energy from renewable sources and finding the highest energy efficiency from source to service,” he says. “Among these possibilities, biomethane [which is already being used to fuel cars in some areas] is an important, but only limited part of the energy equation. Electricity from renewable sources will play the dominant role.”To Bossel, this means focusing on the establishment of an efficient “electron economy.” In an electron economy, most energy would be distributed with highest efficiency by electricity and the shortest route in an existing infrastructure could be taken. The efficiency of an electron economy is not affected by any wasteful conversions from physical to chemical and from chemical to physical energy. In contrast, a hydrogen economy is based on two such conversions (electrolysis and fuel cells or hydrogen engines). “An electron economy can offer the shortest, most efficient and most economical way of transporting the sustainable ‘green’ energy to the consumer,” he says. “With the exception of biomass and some solar or geothermal heat, wind, water, solar, geothermal, heat from waste incineration, etc. become available as electricity. Electricity could provide power for cars, comfortable temperature in buildings, heat, light, communication, etc. “In a sustainable energy future, electricity will become the prime energy carrier. We now have to focus our research on electricity storage, electric cars and the modernization of the existing electricity infrastructure.”Citation: Bossel, Ulf. “Does a Hydrogen Economy Make Sense?” Proceedings of the IEEE. Vol. 94, No. 10, October 2006.By Lisa Zyga, Copyright 2006 Physorg.com 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.last_img read more

Counterintuitive physics may help everyone drive home quicker

first_imgNetwork of the main roads in Boston-Cambridge. Road colors indicate the amount of delay caused in the Nash flow if the road is removed (red indicating the greatest delay, blue indicating no delay). Black dotted roads are those whose removal reduces the travel time, a counterintuitive effect known as Braess’s paradox. Image credit: Hyejin Youn, et al. But if many drivers could change their routes simultaneously, then the effect might be a decrease in everyone’s travel time, and society would come closer to the social optimum rather than languishing in the Nash equilibrium. The scientists found that modifying the network structure can sometimes lead to faster overall travel times, since network changes affect everyone. Surprisingly, they found that closing certain roads can sometimes increase efficiency and allow drivers to travel faster.This counterintuitive result, that adding extra capacity to a network can sometimes reduce its overall efficiency, is called Braess’s paradox. The paradox exists because the Nash equilibrium and the social optimum react in different ways to changes in the network. Specifically, closing a road cannot improve the socially optimal travel time, but it could potentially improve the Nash travel time. This is because individuals seeking their own fastest times may get further away from the social optimum by taking the individually-optimal roads, and closing those roads forces them to take the socially optimal path. In the same way, adding new roads in an attempt to decrease congestion might even create more delay in the Nash equilibrium, but not necessarily decrease congestion in the social optimum strategy.“Braess’s paradox is interesting and counterintuitive,” the authors explained. “It is still controversial to say that closing a road is the best way to deal with a complex traffic network. Instead, we would rather emphasize that opening a new road without careful consideration can worsen the system contrary to the original intention.”The scientists noted that studying traffic flow could not only help planners design better road networks, but could also have applications in other areas of science, such as electronics and economics. For example, physicists know that removing wires in an electric circuit can sometimes counterintuitively increase the conductance, similar to how removing roads can sometimes increase traffic flow. Understanding the agents’ behaviors in a network can also be useful for designing networks such as the Internet and peer-to-peer file sharing, as well as optimizing (or minimizing) flow in many different kinds of networks. “It was surprising and delighting at first: similar principles also emerge in physics without having a direct connection to game theory,” the authors said. More information: Youn, Hyejin; Gastner, Michael T.; and Jeong, Hawoong. “Price of Anarchy in Transportation Networks: Efficiency and Optimality Control.” Physical Review Letters 101, 128701 (2008).Copyright 2008 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Commercial supersonic aircraft could return to the skies 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 furthercenter_img A recent study has investigated just how much time is lost due to individuals opting for strategies that maximize their own personal utility rather than the social optimum, which often aren’t the same. Physicists Hyejin Youn and Hawoong Jeong from the Korea Advanced Institute of Science and Technology in Daejeon, Korea, and computer scientist Michael Gastner from the Santa Fe Institute and the University of New Mexico in the US, call this lost time “the price of anarchy” (POA) that society must pay for the lack of individual coordination. Defined as the ratio of the total travel time of an individual’s optimal route to the total travel time of society’s optimal routes, a high POA means that individuals pursuing the best route for themselves are slowing down the overall traffic flow. When analyzing the traffic in three major cities – Boston, London, and New York City – the researchers found that individuals waste up to 30%, 24%, and 28% of their travel time, respectively, due to choosing a personally optimal route instead of a socially optimal one. The team also calculated the POA for four simulated traffic networks, and found similar results.“People usually believe that inefficiency can be lessened by providing more information,” the scientists told PhysOrg.com. “On the contrary, our model assumes the full information of traffic and shortest paths in a given traffic condition for every player; that is, all the traffic conditions are known to every player. As GPS and computer-modeling-based devices are developed more and more, we believe the drivers follow [an individually optimal] flow more and more.”At the core of the price of anarchy are two related concepts: Waldrop’s principle and the Nash equilibrium. Waldrop’s principle, which is fairly obvious, says that humans approach the problem of finding routes in a network from the self-interested perspective of finding the quickest route for themselves. The second concept, the Nash equilibrium, occurs when an individual cannot choose a better strategy for himself if other individuals keep their strategies unchanged (i.e. an individual can not improve his situation by changing unilaterally). In the traffic situation, say you know which routes the other drivers take, maybe because you’ve tried different routes to find out which is the fastest way to get home from work. After trying different routes, you choose the route that is fastest for yourself. Then you cannot find a faster route as long as the other drivers stick to their same routes (which they do, because they cannot find faster routes, either). Citation: Counterintuitive physics may help everyone drive home quicker (2008, October 2) retrieved 18 August 2019 from https://phys.org/news/2008-10-counterintuitive-physics-home-quicker.html If you’re trying to drive to a destination as quickly as possible, you might think that knowing the traffic conditions would help you choose the quickest route for yourself. Traffic reports and new GPS technologies that provide traffic data are based on this assumption – but scientists have found that knowing this information may do more harm than good.last_img read more

WPA WiFi Encryption Cracked In Sixty Seconds

first_img Citation: WPA Wi-Fi Encryption Cracked In Sixty Seconds (2009, August 28) retrieved 18 August 2019 from https://phys.org/news/2009-08-wpa-wi-fi-encryption-sixty-seconds.html (PhysOrg.com) — Two Japanese computer scientists have developed a way to crack the WPA encryption between wireless routes and devices in 60 seconds. Explore further The Final ‘Final’ Nail in WEP’s Coffin?center_img Using this attack method, hackers can read encrypted data sent between wireless routers and computers. These attacks only work when a router’s wireless security is set for WPA using Temporal Key Integrity Protocol (TKIP) algorithm. About a year ago security researchers explained how WPA could be cracked. The Japanese computer scientists took this theoretical approach and turned it into reality. All this is explained in a paper that was presented at the Joint Workshop on Information Security that was held in Kaohsiung, Taiwan this month. These attacks can be avoided by using the more recent WPA2 or WPA encryption systems that use a stronger algorithm, AES (Advanced Encryption Standard). Wireless routers have a long history of security problems that started back in 1997, when the Wired Equivalent Privacy (WEP) system was first introduced. Two years latter WEP was cracked and rendered useless as an effective security option.WPA with TKIP was meant to be an interim encryption method for Wi-Fi security until a stronger algorithm was developed. Going forward the use of WPA2 should be the standard method for Wi-Fi security. As of March 2006, WPA2 has been certified in wireless router. Going forward users today should use either WPA2 or WPA with AES encryption in their wireless router.Via: TechWatch© 2009 PhysOrg.com 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.last_img read more

Androgenetic species of clam utilizes rare gene capture

first_imgCorbicula fluminea. Image credit: USGS 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. © 2010 PhysOrg.com Citation: Androgenetic species of clam utilizes rare gene capture (2011, May 24) retrieved 18 August 2019 from https://phys.org/news/2011-05-androgenetic-species-clam-rare-gene.html The Corbicula clam is a freshwater species of clams that originated in China and Taiwan but can now be found all over the world. The clams utilize asexual reproduction known as androgensis where the offspring are essentially clones of the male parent. Asexual reproduction lacks genetic recombination and can eventually lead to mutations and possible lineage extinction. This new study reveals that the Corbicula clam may have just found a way to avoid this mutation issue.Hillis and his team looked at the genomes of 19 Corbicula species found throughout the world (both sexual and asexual) and found groups of genes which belonged to one species would show up in another one. This would not occur if the asexual species were strict with their cloning. Hillis found that these clams were essentially using the eggs of other species and occasionally capturing the maternal nuclear DNA in order to replenish the clone’s lineage and avoid lineage mutations.The Corbicula clam is also known for its sudden population increases and has become a pest in many areas of the world. Hillis now plans to look at if there is a connection between the population booms and this rare gene capture event. Explore further More information: Rare gene capture in predominantly androgenetic species, PNAS, Published online before print May 23, 2011, doi: 10.1073/pnas.1106742108AbstractThe long-term persistence of completely asexual species is unexpected. Although asexuality has short-term evolutionary advantages, a lack of genetic recombination leads to the accumulation over time of deleterious mutations. The loss of individual fitness as a result of accumulated deleterious mutations is expected to lead to reduced population fitness and possible lineage extinction. Persistent lineages of asexual, all-female clones (parthenogenetic and gynogenetic species) avoid the negative effects of asexual reproduction through the production of rare males, or otherwise exhibit some degree of genetic recombination. Another form of asexuality, known as androgenesis, results in offspring that are clones of the male parent. Several species of the Asian clam genus Corbicula reproduce via androgenesis. We compared gene trees of mitochondrial and nuclear loci from multiple sexual and androgenetic species across the global distribution of Corbicula to test the hypothesis of long-term clonality of the androgenetic species. Our results indicate that low levels of genetic capture of maternal nuclear DNA from other species occur within otherwise androgenetic lineages of Corbicula. The rare capture of genetic material from other species may allow androgenetic lineages of Corbicula to mitigate the effects of deleterious mutation accumulation and increase potentially adaptive variation. Models comparing the relative advantages and disadvantages of sexual and asexual reproduction should consider the possibility of rare genetic recombination, because such events seem to be nearly ubiquitous among otherwise asexual species. (PhysOrg.com) — In a new study published in the Proceedings of the National Academy of Sciences, biologist David Hillis from the University of Texas shows how the freshwater Corbicula clam utilizes rare gene capture to avoid the accumulation of mutations in their androgenetic lines. Study shows value of sexual reproduction versus asexual reproductionlast_img read more

Almost half of Americans yawn over 4G LTE

first_img TeliaSonera launches first commercial 4G/LTE network Who needs faster wireless networks? Nearly half of US consumers say they don’t. A new survey finds that nearly half of U.S. consumers feel they just do not need 4G LTE. “Colossal power!” “Scorching speed!” “Take your office across the map!” Promotional slogans about 4G LTE devices from carriers and phone vendors about fourth-generation (4G) Long Term Evolution (LTE) networks apparently are not working. The survey from investment firm Piper Jaffray polled 3,000 individuals, results of which were released in a research note this week by analyst Christopher Larsen. A total of 47% of US consumers in the survey felt they have no need for 4G LTE- and only 15 percent of those polled thought 4G LTE is the best network technology.The Piper Jaffray survey also found that consumers are ambivalent about which U.S. carrier has the best 4G LTE network. Among those polled, 51 percent indicated they don’t know who has the best 4G network, or that all 4G networks are the same.Apple released its first 4G LTE device earlier this year with the third-generation iPad. Apple’s next iPhone 5 is expected to also feature 4G LTE connectivity. “This model will almost certainly include 4G LTE wireless capabilities because it would be innovation suicide to not offer it,” said VentureBeat recently. “Top-notch Android phones have been offering 4G data connections since before the iPhone 4S launched.”Interestingly, more enthusiasm according to poll results was shown toward the word iPhone than discussions of connectivity. The poll asked consumers about Apple’s next iPhone, and found that 55 percent of those surveyed said they are considering purchasing it. Of the 55 percent contemplating the iPhone purchase, 44 percent said they would choose Verizon as their carrier; 29 percent said AT&T; 14 percent were for Sprint; and 13 percent for T-Mobile which is not expected to offer the new smartphone.Larsen said that this mixed bag of carrier choice results is good news for them all. Verizon gains from brand recognition, but the fact that so many consumers don’t have an opinion about the different 4G networks means that there’s still time for other carriers to win more consumer attention. The poll’s results generally show competition opportunities for all carriers regarding 4G LTE.The poll also indicates an odd disconnect between a lack of marketing success in sparking 4G LTE awareness in consumers and actual technology advancements. Carriers are busy expanding their networks and providing more 4G LTE coverage; vendors are busy creating buzz about their devices’ 4g LTE features at tradeshows and technology forums.4G LTE delivers mobile network speeds faster than 3G networks. As of Q4 2011, thirty-eight mobile network operators worldwide had launched 4G LTE networks commercially. According to a Reportlinker.com study released this month, governments worldwide have held 4G spectrum auctions or are planning to in coming years, and many Tier 1 mobile operators are building and deploying commercial LTE services. Key drivers are higher data speeds, simplified all-IP networks and the commercial availability of over 200 4G LTE -enabled devices. For consumers, the 4G LTE technology will enable streaming, downloading, and uploading data and playing online games faster than before. With all this activity, nonetheless, the poll results have come as a rude reminder that American consumers are not, at least as of yet, really focused on 4G LTE. Motorola Atrix 4G © 2012 Phys.Orgcenter_img Citation: Almost half of Americans yawn over 4G LTE (2012, August 24) retrieved 18 August 2019 from https://phys.org/news/2012-08-americans-4g-lte.html 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 furtherlast_img read more

MOF speedboat study adds spark to smart autonomous motors

first_img “Autonomous motors of a metal–organic framework powered by reorganization of self-assembled peptides at interfaces” has been published in the journal Nature Materials. The journal presents new research in materials science and engineering. The study authors noted that a variety of microsystems have been developed that harness energy and convert it to mechanical motion, but they have developed “new autonomous biochemical motors by integrating a metal–organic framework (MOF) and self-assembling peptides.”.The team designed a type of molecular motor that is capable of propelling itself across a liquid surface. They used a highly porous MOF device constructed to leak organic peptide molecules out of the slit, which propels the boat. “The MOF is applied as an energy-storing cell that assembles peptides inside nanoscale pores of the coordination framework,” they wrote. The researchers, led by Hiroshi Matsui of Hunter College, filled the pores in an MOF with the peptide diphenylalanine and floated the particles on water. Adding ethylenediaminetetraacetate (EDTA) partially degraded the MOF which allowed the peptide to escape from the pores. “The neat MOF particle is descended immediately to the bottom of the EDTA solution with no transitional and rotational motions and it does not decompose visibly under the microscope in the time frame of this experimental setting,” they wrote.Explaining their work further, Chemistry World, the Royal Society of Chemistry publication, said. “Upon reaching the water, the peptide spontaneously reassembles into a hydrophobic aggregate, reducing the surface tension at that point. The creation of a surface-tension gradient forces the particles to move towards the area with higher surface tension, a phenomenon known as the Marangoni effect.”Scientific efforts to imitate nature’s motile life forms have been part of the quest for autonomous microscopic machines. The study authors said that “This demonstration opens the route towards new applications of MOFs and reconfigurable molecular self-assembly, possibly evolving into a smart autonomous motor capable of mimicking swimming bacteria and, with integrated recognition units, harvesting target chemicals.” The authors are Yasuhiro Ikezoe, Gosuke Washino, Takashi Uemura, Susumu Kitagawa and Hiroshi Matsui. Credit: Kyoto University ‘Seeding’ the next generation of smart materials © 2012 Phys.org (Phys.org)—Research towards self-propelling microscopic machines has a boost in the form of a newly published study by researchers at City University of New York-Hunter College and Kyoto University in Japan. They worked out a ‘molecular motor’ that can move, speedboat-style, across a liquid surface. Journal information: Nature Materialscenter_img Citation: MOF speedboat study adds spark to smart autonomous motors (2012, October 30) retrieved 18 August 2019 from https://phys.org/news/2012-10-mof-speedboat-smart-autonomous-motors.html Explore further More information: www.nature.com/nmat/journal/va … t/full/nmat3461.htmlNature Materials, 2012, DOI: 10.1038/nmat3461 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.last_img read more

Researchers perform first direct measurement of Van der Waals force

first_img Citation: Researchers perform first direct measurement of Van der Waals force (2013, July 8) retrieved 18 August 2019 from https://phys.org/news/2013-07-van-der-waals.html © 2013 Phys.org More information: Direct Measurement of the van der Waals Interaction between Two Rydberg Atoms, Phys. Rev. Lett. 110, 263201 (2013) prl.aps.org/abstract/PRL/v110/i26/e263201AbstractWe report the direct measurement of the van der Waals interaction between two isolated, single Rydberg atoms separated by a controlled distance of a few micrometers. Working in a regime where the single-atom Rabi frequency for excitation to the Rydberg state is comparable to the interaction, we observe partial Rydberg blockade, whereby the time-dependent populations of the various two-atom states exhibit coherent oscillations with several frequencies. Quantitative comparison of the data with a simple model based on the optical Bloch equations allows us to extract the van der Waals energy, and observe its characteristic C6/R6 dependence. The measured C6 coefficients agree well with ab initio calculations, and we observe their dramatic increase with the principal quantum number n of the Rydberg state. (Phys.org) —Researchers working at the French National Center for Scientific Research have for the first time, directly measured the Van der Waals force between two atoms. In their paper published in the journal Physical Review Letters, the team describes how they used lasers to hold two atoms steady and a third laser to measure the Van der Waals force between them. Explore further The weak force between atoms, named after its discoverer Johannes Diderik van der Waals is evident in the behavior of many materials—it’s what keeps most gas molecules together. Scientists have also discovered that it’s also what allows a gecko’s toes to stick to a smooth wall. But, because the weak force is only apparent when atoms are very close together, scientists have until now been unable to measure it directly.In this new effort, the research team chose to use Rydberg atoms as part of their study. Such atoms are large and one of their electrons has a highly charged state. This makes them a good candidate for attempting to measure the Van der Waals force—they have more force between them than most other atom pairs and because of that can be measured at longer distances.They started by firing a pair of lasers at twin Rydberg atoms. Doing so held them steady. Next, they fired a third laser at the two atoms causing them to oscillate at a desired frequency. By measuring the oscillations, the researchers were able to work out mathematically the Van der Waals force between them. More specifically, the researchers measured oscillations between ground and excited states, noting that the distance between the two atoms at the time of measurement was key—too close and the excitation of one of the atoms overwhelmed the other—too far and the force between the atoms became too weak to measure. Using the third laser as optic tweezers allowed for adjusting the distance between the two atoms, which ultimately led to just the right distance for measurement.The team also noted that the technique used for measuring the Van der Waals force also led to the oscillating atoms evolving to a fully coherent state. This means the technique could be used to create quantum logic gates, which might prove useful in creating a quantum computer.center_img First single-molecule measurement of Van Der Waals interactions at metal-organic interface Journal information: Physical Review Letters Mapping out the van der Waals interaction between two atoms. (a) In the experiment of Béguin et al. two atoms are trapped in the foci of two laser beams separated by a distance R. (b) Depending on R, the excitation laser field can couple the ground state |gg of the atomic pair to states containing one atom in the Rydberg state (|gr and |rg, respectively), or to a state with both atoms populating the Rydberg state |rr. The energy of the latter state is strongly shifted because of the van der Waals interaction UvdW between the atoms (see level diagram in the upper left), resulting in a distance-dependent coherent excitation dynamics of the atomic pair system. (c) By analyzing the time evolution of the atom-pair state, Béguin et al. deduce the van der Waals energy shift as a function of interatomic distance for different Rydberg states. Credit: Physics 6, 71 (2013) DOI: 10.1103/Physics.6.71 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.last_img read more

Nanodiamond tech lights new path in medical diagnostics

first_imgCredit: Youris © 2014 Phys.org Earlier this month TechCrunch featured a look at a company that wants to make a difference in finding cancer before it spreads using nanodiamond-based technology. The idea is that nanodiamonds can detect molecular abnormalities at an early stage, and as such could help a patient’s chances for survival. The company is called Bikanta. Founded in 2013, the company is interested in what fluorescent diamonds inside the body can mean to the future of medical diagnostics. The company website said it has developed nanodiamond-based technology; nanodiamonds are superior optical probes with the key beneficial features such as biocompatibility, brightness and signal stability, and cost, the site added. Nanodiamonds are exquisitely sensitive to magnetic fields, said the company, and this sensitivity can be used to reduce background noise more than 100-fold over current methods and to improve visualization deeper into the body. Bikanta said it is also designing novel imaging scanners and microscopes to improve detection capabilities. Citation: Nanodiamond tech lights new path in medical diagnostics (2014, August 11) retrieved 18 August 2019 from https://phys.org/news/2014-08-nanodiamond-tech-path-medical-diagnostics.html Ambika Bumb, PhD, is the CEO. A Georgia Tech graduate, she went on to receive her doctorate from Oxford. She became interested in the challenges confronting cancer research. Is there a better way to find disease as its source? Bumb, said TechCrunch, “discovered that crushing up essentially imperfect diamonds into dust created a fluorescent, reflective light that could highlight any molecular abnormality.” She added in TechCrunch that it was like having “a flashlight inside your body that basically lasts forever.”Her company site notes the diagnostic advantages of nanodiamonds. “Fluorescent nanodiamonds never photobleach or blink. They are tiny fluorescent sources of steady and permanent near infrared light that can be leveraged to detect targets deep in tissue.” In an additional follow-up comment to the TechCrunch article, Bumb explained, “Current optical imaging agents do have the ability to specifically bind and image targets in tissue and in vivo. Where they are technically limited is by signal loss issues (photobleaching, photoblinking). Fluorescent nanodiamonds have permanent and infinitely stable fluorescent signal. They are also imageable deeper into tissue because of a second magnetic sensitivity property that can be manipulated to improve signal-to-noise ratio.”This would not be the first time close attention has been paid to nanodiamonds in the context of cancer detection. European researchers are also interested. An article appeared last year in youris.com, titled “Nanodiamonds: a cancer patient’s best friend?” The article said, “nanometric scale diamond particles could offer a new way to detect cancer far earlier than previously thought. This is precisely the objective of a research project called Dinamo, funded by the EU. Specifically, it aims to develop a non-invasive nanotechnology sensing platform for real-time monitoring of biomolecular processes in living cancer cells.” More information: — www.youris.com/Health/Cancer/N … ientS_Best_Friend.kl— www.bikanta.com/ Explore further Silk coat for diamonds makes sleek new imaging and drug delivery tool 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.last_img read more

Experiment suggests silicon missing element in Earths core

first_img 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. Diagram of the Earth. Credit: Kelvinsong/Wikipeida Earth scientists have concluded that approximately 85 percent of the Earth’s core is made of iron while nickel makes up an additional 10 percent—but the final 5 percent has been a bit of a mystery. In this new effort, the researchers conducted lab experiments that gave results suggesting that the final ingredient is silicon.To figure out which elements exist in the Earth’s core, researchers have been building virtual Earths in labs and then subjecting them to real-life conditions such as heat and pressure. For now, this is the only approach possible because the core is far too deep to dig a hole and send a probe down—it is approximately 3,000 km below the surface and is a relatively small target—about the size of Pluto. Experiments have consisted of building cores containing different materials, subjecting them to heat and pressure and then sending seismic waves through them to compare with real ones sent through the real core. Silicon has been considered as a possibility before due to the ease with which it bonds with metals, but it had not been thoroughly tested. The researchers in Japan heated their iron, nickel and silicon core to 6,000C° and applied pressure 3.6 million times that at the surface of the planet. Seismic analysis indicated the mixture they had created matched that at the real Earth’s core, strongly suggesting they had found the missing element.As the researchers note, understanding the true makeup of our planet, including its core, may help to better understand its history. Learning about the materials that make up the core today offers a way to learn more about what the interior parts of the planet may have been like billions of years ago, such as when the core separated from rockier material around it. The results of the new effort also suggest that oxygen is likely not very abundant in the core, which some in the field have suggested was a real possibility. Researchers offer ‘proof’ that oxygen is the only light element in the Earth’s core More information: MR22A-01: Sound velocity of iron-light element compounds and the chemical structure of the inner core, AGU Fall Meeting 2016, agu.confex.com/agu/fm16/meetin … app.cgi/Paper/153611AbstractThe light elements in the core could constrain the conditions of accretion, subsequent magma ocean, and core formation stages of the Earth. There are several studies for sound velocity measurements of the iron-light elements alloys. However, the measurements are not enough to constrain the light element abundance in the core tightly at present due to inter-laboratory inconsistencies using different methods which are originated from the difficulties to make such measurements under the extreme conditions. We measured the sound velocity of iron alloy compounds at high pressure and temperature relevant to the Earth’s core using double-sided laser heating of a DAC combined with inelastic X-ray scattering at SPring-8.We measured the compressional velocity of hcp-Fe up to 166 GPa and 3000 K, and derived a clear temperature dependence of the Birch’s law for hcp-Fe. We measured the compressional velocity of Fe0.89Si0.11 alloy and Fe3C at high pressure and temperature, and we could not detect temperature dependency in Birch’s law in these compounds. Additionally, we measured the sound velocity of Fe3S, Fe0.83Ni0.09Si0.08 alloy, and FeH at high pressure. Combining our new data set which showed remarkable differences from previous data on the sound velocity, we present a model of the chemical structure of the inner core. The outer core composition was also estimated based on partitioning behaviors of these light elements between solid and liquid iron alloys under the core conditions. Explore furthercenter_img Mystery at the core of the earth © 2017 Phys.org (Phys.org)—A team of researchers from several institutions in Japan has conducted experiments with results that indicate that silicon is likely the missing element in Earth’s core. The group gave a presentation outlining their findings at a recent meeting of the American Geophysical Union. Citation: Experiment suggests silicon missing element in Earth’s core (2017, January 11) retrieved 18 August 2019 from https://phys.org/news/2017-01-silicon-element-earth-core.htmllast_img read more

2000yearold mummy found near Russian reservoir

first_img Museum says mummy was Peruvian girl who lived centuries ago The archaeologists reported that along with the remains, there was a belt with beads and a buckle made of jet, a vase resembling those used by Huns of the period, and a box made of birch wood that held a small mirror. Other assorted ceramic utensils were also found. Initial examination of the mummified remains revealed patches of skin, soft tissue and cloth remnants that appeared to be made of silk.The researchers noted that the area where the grave was found is normally underwater, but this year, the reservoir created by the dam was abnormally low, exposing ground that had been submerged since the 1980s. As the researchers were exploring the exposed land last month, they came upon the tomb.The researchers suggest the clothing and materials in the grave indicate the girl was likely a nomadic Hun—likely one of high regard. She could have been part of the nobility. They also note that the vase contained what appeared to be a funeral meal and that a sack of pine nuts had been placed on her chest. The Huns, the researchers note, lived in parts of what is now modern China and Siberia almost 2000 years ago. They were migratory, and prior studies have shown they tended to mix with local people.The remains and other artifacts have been removed from the gravesite and have been transported to a location suitable for studying them. The researchers report that a lot of work is required to learn more about the girl’s origins and how she came to be mummified. They will also be working to understand how her remains and other artifacts were able to withstand being submerged under the reservoir for over 30 years. Credit: Marina Kilunovskaya A team of researchers from St Petersburg’s Institute of History of Material Culture has found the naturalized remains of a mummy in an ancient gravesite near the Sayano-Shushenskaya Dam in Russia. In speaking with the press, the researchers reported that the remains were those of a mummified young girl lying in a stone gravesite and that they believe she lived almost 2000 years ago. © 2018 Phys.orgcenter_img Explore further 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. Citation: 2000-year-old mummy found near Russian reservoir (2018, June 29) retrieved 18 August 2019 from https://phys.org/news/2018-06-year-old-mummy-russian-reservoir.htmllast_img read more