The Physics of Gecko Toes

first_imgWhy would anyone want to know the details of physical forces when gecko feet walk on glass?  Here’s why: “The results have obvious implications for the fabrication of dry adhesives and robotic systems inspired by the gecko’s locomotion mechanism.”  A team of scientists from Santa Barbara and China watched gecko toes peel off glass and wrote up their results in PNAS.1  “The extraordinary climbing ability of geckos is considered a remarkable design of nature that is attributed to the fine structure of its toes,” the paper began.  As the abstract describes the physics involved, it’s more complex than one would think:Geckos can run rapidly on walls and ceilings, requiring high friction forces (on walls) and adhesion forces (on ceilings), with typical step intervals of {approx} 20 ms.  The rapid switching between gecko foot attachment and detachment is analyzed theoretically based on a tape model that incorporates the adhesion and friction forces originating from the van der Waals forces between the submicron-sized spatulae and the substrate, which are controlled by the (macroscopic) actions of the gecko toes.  The pulling force of a spatula along its shaft with an angle {theta} between 0 and 90° to the substrate, has a “normal adhesion force” contribution, produced at the spatula-substrate bifurcation zone, and a “lateral friction force” contribution from the part of spatula still in contact with the substrate.  High net friction and adhesion forces on the whole gecko are obtained by rolling down and gripping the toes inward to realize small pulling angles {theta} between the large number of spatulae in contact with the substrate.  To detach, the high adhesion/friction is rapidly reduced to a very low value by rolling the toes upward and backward, which, mediated by the lever function of the setal shaft, peels the spatulae off perpendicularly from the substrates.  By these mechanisms, both the adhesion and friction forces of geckos can be changed over three orders of magnitude, allowing for the swift attachment and detachment during gecko motion.Will this be on the test?1Tian et al, “Adhesion and friction in gecko toe attachment and detachment,” Proceedings of the National Academy of Sciences USA, 10.1073/pnas.0608841103, published online before print December 5, 2006.You probably didn’t realize that geckos were such good physicists.  What’s really cool is thinking about the day we will have gecko boots and can play like Spiderman.(Visited 18 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img read more

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Cape floral heritage site expands

first_img6 July 2015The United Nations Education, Scientific and Cultural Organisation (Unesco) has approved the extension of the Cape Floral Region Protected Areas World Heritage Site.Unesco said on its website on 3 July that the Cape Floral Region was inscribed on to the World Heritage List in 2004. At the time of inscription, the site was made up of eight protected areas comprising about 553 000 hectares.The extension almost doubles the size of the world heritage site to 1 094 742 hectares and includes Table Mountain National Park, Agulhas complex, Langeberg complex, Anysberg Nature Reserve, Swartberg complex, Baviaanskloof complex and the Garden Route complex.Diversity“It is one of the world’s great centres of terrestrial biodiversity,” Unesco says of the Cape Floral Region. “The extended property includes national parks, nature reserves, wilderness areas, state forests and mountain catchment areas.”Compared with the rest of the world, the extended Cape Floral Region is one of the richest in plant life. “It represents less than 0.5% of the area of Africa but is home to nearly 20% of the continent’s flora, with some 69% of the 9 000 identified plant species being endemic to the area,” says the South African government.A country’s pride“South Africa is delighted to add more protected areas to its portfolio of world heritage properties,” said Environmental Affairs Deputy Minister Barbara Thomson.“The country has in the last few years learned a few lessons in management of its world heritage sites and has through its engagement with the committee and the advisory bodies achieved high standards of conservation to levels expected by Unesco.”Having world heritage sites in the country ensures protection of the areas, and it also has potential to boost economic development, create jobs and develop skills.There are eight Unesco world heritage sites in South Africa. Properties inscribed on the cultural list are: the Fossil Hominid Sites of South Africa, Mapungubwe Cultural Landscape, Richtersveld Cultural and Botanical Landscape, and Robben Island. Those on the natural list are: the Cape Floral Region, iSimangaliso Wetland Park, and Vredefort Dome. The Maloti-Drakensberg Park, a transboundary reserve with Lesotho, is on the mixed list.SAinfo reporterlast_img read more

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IIT, IIM students expand scope of their scholarship scheme to Northeast

first_imgA group of students from the Indian Institutes of Technology, the Indian Institutes of Management and the National Institutes of Technology have expanded the scope of their “career-shaping” examination and scholarship to urban centres in the Northeast.The group from these three institutes had started the “one nation, one exam” National Level Common Entrance Examination (NLCEE) for classes 9-12 this year. The first exam on March 31, conducted across 62 centres across India, had 22,000 students.“This time, we have included all tier 2 and tier 3 cities in the northeast as our examination centres for better penetration and opportunity to underprivileged students in geographically-challenged areas. We are also offering an additional scholarship of up to ₹ 60,000 to deserving students besides an opportunity to visit research and development centres such as the Indian Space Research Organisation and the IITs for 3-15 days,” NLCEE’s overall coordinator Ullas M.S., an NIT Karnataka product, told The Hindu.NLCEE was founded by Ravi Nishant who studied in IIT-Guwahati.Mr. Ullas said the group hired interns from different IITs and NITs to work together on the NLCEE project.“For the exam, there is no need for prerequisite preparation as it is not designed to test one’s technical skills in maths or science. It is meant to test one’s aptitude, creativity in problem-solving, and thinking outside the box,” he said.He said that the NLCEE team would conduct the exam in two phases. For the first, examination centres will operate in more than 100 cities in the country. Based on the results, the top 1,000 students would be selected for the second phase and rewarded according to the rank achieved.“In the second phase, we will shortlist 100 children, then provide significant educational exposure to the deserved by offering visits to the ISRO, the IITs, etc. It can make them motivated, get an overall idea about all kinds of educational streams or courses available, and then take the right decision for their further studies. The NLCEE shall pay all the expenses of the children’s living and transportation,” Mr. Ullas said.last_img read more

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10 months agoJuventus clear Higuain to join Chelsea

first_imgJuventus clear Higuain to join Chelseaby Paul Vegas10 months agoSend to a friendShare the loveGonzalo Higuain has requested a transfer to Chelsea.Sportmediaset says the striker has asked Juventus for permission to make the move to Stamford Bridge.The Argentinian striker has flattered to deceive on loan at AC Milan, where he has scored just five Serie A goals in 14 games.The 31-year-old is desperate to reunite with former boss Maurizio Sarri.Higuain banged in 38 goals in 42 matches under the tutelage of Sarri in their only season together at Napoli, before he jumped ship to sign for the Old Lady.And the Italian news outlet also claims that Juve have given the World Cup runner-up the green light for the deal to go ahead. TagsTransfersAbout the authorPaul VegasShare the loveHave your saylast_img read more

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10 months agoChelsea midfielder Loftus-Cheek in tears after back injury

first_imgAbout the authorPaul VegasShare the loveHave your say Chelsea midfielder Loftus-Cheek in tears after back injuryby Paul Vegas10 months agoSend to a friendShare the loveChelsea midfielder Ruben Loftus-Cheek suffered a back injury in their FA Cup win over Nottingham Forest.Two goals from Alvaro Morata saw the Blues book their place in the fourth round but the win was dampened somewhat by Loftus-Cheek’s injury.The 22-year-old was forced to exit the game in tears minutes before half-time after his back trouble flared up at Stamford Bridge.Blues coach Carlo Cudicini said, “We are very sorry for the kid.”It is a pity.It is something that’s affecting him, something we need to look at and resolve. “It has been going on for a while and maybe he might have to stop for a bit to resolve. It is a pity because he is doing very well.” last_img read more

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Bangladesh to host Zimbabwe despite ICC ban

first_imgDhaka: Bangladesh will host Zimbabwe for a tri-nations Twenty20 tournament in September despite the African nation being suspended by the game’s world body, an official of the Bangladesh Cricket Board said Thursday. The International Cricket Council (ICC) suspended Zimbabwe in July over a failure to keep the sport free from government interference, putting the country’s participation in multi-nation events in doubt. “We have been informed by the concerned officials that there is no bar on Zimbabwe playing in bilateral matches.cThey are only suspended from ICC events. This is why we included them in the series,” BCB spokesman Jalal Yunus told AFP. Also Read – Puducherry on top after 8-wkt win over Chandigarh Afghanistan are the third team in the tournament scheduled to be held from September 13 to 24. Bangladesh were originally scheduled to play a bilateral series against Afghanistan in September, but officials said Zimbabwe had been included in the series following a request from the strife-torn country. The tri-series will be preceded by Afghanistan’s maiden Test match against Bangladesh in Chittagong from September 5 to 9. Fixtures: Also Read – Vijender’s next fight on Nov 22, opponent to be announced laterAug 30: Afghanistan arrive in Bangladesh Sept 1-2: Two-day practice match between Afghanistan XI and BCB XI in Chittagong Sept 5-9: First and only Test between Bangladesh and Afghanistan in Chittagong Sept 8: Zimbabwe arrive in Bangladesh Sept 11: T20 practice match between Zimbabwe XI and BCB XI in Fatullah Sept 13: Bangladesh v Zimbabwe tri-nation T20I in Dhaka Sept 14: Afghanistan v Zimbabwe tri-nation T20I in Dhaka Sept 15: Bangladesh v Afghanistan tri-nation T20I in Dhaka Sept 18: Bangladesh v Zimbabwe tri-nation T20I in Chittagong Sept 20: Afghanistan v Zimbabwe tri-nation T20I in Chittagong Sept 21: Bangladesh v Afghanistan tri-nation T20I in Chittagong Sept 24: Final of tri-nation T20I in Dhakalast_img read more

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Podcast Hockeys Modern Dynasty NBA Finals And A Baseball Hacking Scandal

Hot Takedown Video Excerpt: Baseball, Big Data, And Espionage More: Apple Podcasts | ESPN App | RSS | Embed Embed Code Welcome to this week’s episode of Hot Takedown, our podcast where the hot sports takes of the week meet the numbers that prove them right or tear them down. On this week’s show (June 16, 2015), we discuss how LeBron James could win the NBA Finals MVP even if his team loses, whether the Chicago Blackhawks qualify as a dynasty, and the news that the FBI is investigating whether the St. Louis Cardinals hacked data from the Houston Astros. Plus, our Significant Digit of the week, on the second biggest upset in Women’s World Cup history.Stream the episode by clicking the play button, or subscribe using one of the podcast clients we’ve linked to above.Below are some links to what we discuss on this week’s show:Nate Silver says the Blackhawks are a dynasty.The Cardinals are accused of hacking the Astros.Last year, Bloomberg profiled “Ground Control” and Astros General Manager Jeff Luhnow.Neil Paine on how proprietary data is a growing issue in pro sports.Neil Paine on LeBron James possibly going down as the greatest loser ever.Benjamin Morris offers another story about how great James is.Significant Digit: 6 percent. That was Colombia’s win probability going into its game with France, according to our Women’s World Cup predictions. Colombia won 2-0, the second biggest upset in Women’s World Cup history. If you’re a fan of our podcasts, be sure to subscribe on Apple Podcasts and leave a rating/review. That helps spread the word to other listeners. And get in touch by email, on Twitter or in the comments. Tell us what you think, send us hot takes to discuss and tell us why we’re wrong. read more

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