Material Changes its Color Depending on How You Look at It

first_imgChrysochroa vittata (left) and Hoplia coerulea (right) possess natural photonic crystal structures which inspired the design of researchers’ iridescent materials. Image credit: Olivier Deparis, et al. “Imagine a graph where the x axis is the degree of complexity of the nano-structure of an iridescent material and the y-axis is the diversity of basic materials which are used to build the nano-structure,” he says. “Natural iridescent materials are mostly characterized by highly complex structures (involving order, disorder, hierachy, etc.) but employ only a few basic materials to realize these complex structures: that’s the fascinating power of nature to evolve from basic structures to the most sophisticated and/or optimized ones during millions years of adaptation to the changing environment. In our graphical representation, natural iridescent materials therefore are confined to a region of high x (complexity) and low y (diversity) values.”On the other hand, Deparis continues, artificial materials are the opposite. “Due to limitations in both industrial fabrication processes and human imagination, artificial photonic materials are often characterized by rather simple structures but often employ a large set of basic materials – think of the doped-semiconductor industry, for example. In our graphical representation, artificial iridescent materials therefore are confined to a region of low x and high y values. Our bio-inspired approach, in which natural structures are used as templates for the design of artificial ones, allows us to target unexplored regions of both high x and high y values, i.e. to come up with new artificial iridescent materials with more complex nano-structures made of basic materials available in a larger chemical composition range.” Using the beetles’ nanometer-scale layers as a template, Deparis and his colleagues designed and fabricated iridescent surfaces out of titanium and silicon oxide layers. There were two variables that determined the iridescent properties: the period of the alternating layers, and the layer thickness ratio (one layer being thicker than the other). The period determined the dominant color (the dominant reflected wavelength) at head-on incidence. The layer thickness ratio largely determined what the scientists call “spectral richness,” which is the extent to which the colors change (or the wavelength shifts) when the viewing angle increases.Based on this understanding, the scientists created iridescent materials that precisely mimick the beetles’ exocuticle coloring. Specifically, C. vittata (the red-to-green beetle) has a layer period of about 200 nanometers, corresponding to its red dominant color. It also has a small layer thickness ratio that causes a fairly large wavelength shift of about 110 nanometers as the viewing angle increases from 20 to 60 degrees. H. coerulea (the blue-to-violet beetle) has a layer period of about 100 nanometers, corresponding to its blue dominant color. Its layer thickness ratio is larger than C. vittata, causing a fairly small wavelength shift of about 20 nanometers over the same viewing angles. “In the case of the present study, this [bio-inspired] approach is exemplified by the fact that we used two materials [titanium and silicon oxide] which were chosen among a large range of available oxides in order to generate very different iridescent aspects by taking advantage of the complexity,” Deparis says. “Here the complexity was introduced by considering the thicknesses of both layers as free and independent parameters, which is not usually the case in the design of standard multilayer Bragg reflectors.”The group also developed a model that can predict the reflectance spectrum of an iridescent material at any viewing angle. By tuning the layer thicknesses, the researchers can now fabricate a wide variety of iridescent materials with vivid, changing colors. Iridescent materials could have uses in various industries on large-scale surfaces, which would be an engineering challenge. Another challenge, the researchers explain, may be the deposition of these multilayer films on different substrates, such as flexible polymer foils or curved objects.“Possible applications of iridescent materials are mainly in art (why not iridescent sculptures!),” says Deparis, “or architecture (glass or metal iridescent panels for decoration), painting (iridescent structural ‘pigments’ in the form of small particles in a solvent), ophtalmic glasses (here, coatings for which the color almost does not change with viewing angle may be interesting, similar to Hoplia coerula).”More information: Deparis, Olivier, Rassart, Marie, Vandenbem, Cédric, Welch, Victoria, Vigneron, Jean Pol, and Lucas, Stéphane. “Structurally tuned iridescent surfaces inspired by nature.” New Journal of Physics 10 (2008) 013032.Copyright 2008 All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of The group of researchers, from the University of Namur in Belgium, has recently fabricated iridescent materials that closely mimic the structure and appearance of two species of Coleoptera beetles. By analyzing the underlying physical mechanisms that cause iridescence, the researchers can predict the colors displayed by specific material structures, and, conversely, determine what kind of structural properties are required to display certain colors. With this understanding, they have created a colorful variety of iridescent materials.“In the context of iridescent materials, the greatest significance of our study is probably the fact that we are discovering new iridescent photonic structures in nature which give us inspiration to synthesize artificial materials whose (nano-) structures are presently out of reach of the human imagination,” lead author Olivier Deparis tells a recent issue of the New Journal of Physics, the scientists explain what causes the vivid colors to change based on viewing angle. The beetles in the study (Chrysochroa vittata and Hoplia coerulea) have layers of materials with different thicknesses. When light waves reflect off the different layers at different depths, the light waves interfere. So when you look at a beetle, the color you see is due to the light’s reflection peak off not just one surface, but many surfaces combined. As your viewing angle increases from head-on to a side view, the reflectance peak shifts to shorter wavelengths. That’s why H. coerulea, for example, appears blue head-on, but violet (shorter wavelengths) from larger viewing angles.Nature’s iridescence is surprisingly diverse. Both beetles – and nearly all animals that exhibit iridescence – use the same bio-material called “chitin“ for achieving a high refractive index, and a combination of air or water for the low refractive index component. Yet, no two species display the same colors. While this great diversity was originally a surprise to scientists, researchers now know that the different layer thicknesses of different species can “tune” the animals’ colors, even if the materials are the same. As Deparis explains, nature’s diversity can offer many benefits for researchers looking to expand the abilities of man-made materials. Citation: Material Changes its Color, Depending on How You Look at It (2008, February 4) retrieved 18 August 2019 from New type of glass inspired by nature is more resistant to impactscenter_img Explore further Looking at the metallic woodboring beetle head-on, the insect appears red. But viewing it from the side, the beetle starts to take on a greenish hue, and then turns completely green at an 80-degree angle. This color-changing feature is called iridescence, and scientists are taking notes from the beetle to design man-made iridescent materials. 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

Sweden wants Norways trash and lots of it

first_img Citation: Sweden wants Norway’s trash (and lots of it) (2012, October 28) retrieved 18 August 2019 from Explore further The numbers are from Eurostat, which said only 1 percent of waste from Swedish households ends up in landfill, in contrast to 38 percent for European countries. In Sweden, some of its waste is either recycled or is composted. Sweden has turned to neighboring countries for their excess waste. Sweden is on an import drive of eight hundred thousand tons of trash from the rest of Europe per year to use in its power plants. Much of the import is coming from Norway. The waste is to satisfy Sweden’s Waste-to-Energy program, with the end goal of converting waste into heat and electricity. Norway is amenable to the agreement as exporting a portion of its trash is more economical than having to burn it. In the plan, toxic waste, ashes remaining from the incineration process, filled with polluting dioxins, will be returned to Norway.While tapping its European neighbors for their garbage might seem unusual, Sweden does not consider itself such an odd duck; rather, as a forward-thinker when it comes to energy efficiencies and the use of waste to supply people’s energy needs. For Sweden, burning garbage in incinerators generates district heating, where heat is distributed by pumping heated water into pipes through residential and commercial buildings. It also provides electricity for homes. Sweden’s strict standards limit emissions from waste incineration and most emissions have fallen considerably because of technical development and better waste sorting. Earlier this year, Catarina Ostlund, a senior advisor for the Swedish Environmental Protection Agency, said that in the future, waste will be valued even more. “Maybe you could sell your waste because there will be a shortage of resources within the world,” Ostlund said.Beyond Norway, Sweden eyes Bulgaria, Romania, Italy and the Baltic countries as possible options for garbage; they are countries that “landfill” a higher percentage of waste than Norway. “I hope that we instead will get the waste from Italy or from Romania or Bulgaria or the Baltic countries because they landfill a lot in these countries. They don’t have any incineration plants or recycling plants, so they need to find a solution for their waste,” she said. Plastic waste: better to burn? More information: … he-nation-10428.html. center_img © 2012 (—Sweden is hungry for trash and has turned to Norway for an offer it would find hard to refuse, no pun intended. Sweden is asking its neighbor for trash. Sweden’s success is Sweden’s problem. Sweden is a model recycler. Thanks to a highly efficient waste management system in Sweden, the vast majority of this household waste can be recovered or reused. As a result, Sweden has run short of garbage. Since it does not produce enough burnable waste for its energy needs, Sweden is suffering a downside to being such an enviable model of recycling. The average in Europe of trash that ends up as waste is 38 percent. Sweden’s is 1 percent. 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

Microsoft sends SkyDrive SDKs and IFTTT tiein to developers

first_img(—Microsoft has announced new tools for developers related to its SkyDrive file-sharing and cloud storage service—namely, SkyDrive SDKs for .NET and Windows Phone 8. SkyDrive is an important integrator for software and hardware coming out of the Microsoft universe; the new developer tools will push SkyDrive further into prominence. A Technology Evangelist for Microsoft, Jim O’Neil, said that the cloud serves up the “connection” experience and within Windows 8 that experience is not “bolted on.” Microsoft sees ‘rebirth’ with new Windows 8 system Citation: Microsoft sends SkyDrive SDKs and IFTTT tie-in to developers (2012, November 19) retrieved 18 August 2019 from More information: … … s-skydrive-sdks.aspx Explore furtherlast_img read more

Field study suggests brain size in ants adheres to specialization hypothesis

first_imgAcacia ants (Pseudomyrmex ferruginea). Credit: Ryan Somma/Wikipedia. Scientists have noticed over the years that organisms that live in colonies tend to have larger brains when the colonies are larger, which has begged the question of whether it’s a colony wide phenomena (brain growth would be due to the need for maintaining social connections) or if it differs by group member specialization (because of a need to learn the skill involved)—the first has led to what is known as the Social Brain hypothesis (SBH), the latter the Task-Specialization hypothesis (TSH). In this latest effort, the researchers looked to find the answer, at least for one species, by traveling to Panama to study acacia ants—they live in the hollows of acacia trees. The ants made good study subjects because the size of their colonies varies. Also, prior research has shown that there are at least two kinds of jobs done by the ants, some workers hang around the base of the tree warding off predators while other workers forage on the leaves of the tree—thus there are two distinct classes of ants in any single colony, unless the colony is small—in that case worker ants are forced to perform both jobs.To find out which hypothesis might apply to the ants, the team ventured to the Parque Natural Metropolitano in Panamá City and studied the activity in 17 different colonies for three months, and also measuring the brains of 34 trunk ants and 29 leaf ants. They found that as the size of the colony increased, the size of the brains of the leaf ants grew as well (most particularly the regions responsible for memory and learning), but the brains of the trunk ants did not. Thus, it was clear that at least for acacia ants, brain size appears to adhere to TSH. © 2015 Citation: Field study suggests brain size in ants adheres to specialization hypothesis (2015, January 7) retrieved 18 August 2019 from (—A small group of researchers working in conjunction with the Smithsonian Tropical Research Institute in Panama has found that for at least one type of ant, the specialization hypothesis appears to apply regarding brain size. In their paper published in Proceedings of the Royal Society B, the team describes their study of various sized ant colonies and ant brains, and what they learned in doing so. More information: Specialization and group size: brain and behavioural correlates of colony size in ants lacking morphological castes, Proceedings of the Royal Society B, Published 7 January 2015. DOI: 10.1098/rspb.2014.2502 ABSTRACTGroup size in both multicellular organisms and animal societies can correlate with the degree of division of labour. For ants, the task specialization hypothesis (TSH) proposes that increased behavioural specialization enabled by larger group size corresponds to anatomical specialization of worker brains. Alternatively, the social brain hypothesis proposes that increased levels of social stimuli in larger colonies lead to enlarged brain regions in all workers, regardless of their task specialization. We tested these hypotheses in acacia ants (Pseudomyrmex spinicola), which exhibit behavioural but not morphological task specialization. In wild colonies, we marked, followed and tested ant workers involved in foraging tasks on the leaves (leaf-ants) and in defensive tasks on the host tree trunk (trunk-ants). Task specialization increased with colony size, especially in defensive tasks. The relationship between colony size and brain region volume was task-dependent, supporting the TSH. Specifically, as colony size increased, the relative size of regions within the mushroom bodies of the brain decreased in trunk-ants but increased in leaf-ants; those regions play important roles in learning and memory. Our findings suggest that workers specialized in defence may have reduced learning abilities relative to leaf-ants; these inferences remain to be tested. In societies with monomorphic workers, brain polymorphism enhanced by group size could be a mechanism by which division of labour is achieved.last_img read more

KMC plans to set up mini pumping stations at four ghats in

first_imgKolkata: The Kolkata Municipal Corporation (KMC) is planning to set up mini pumping stations at four ghats in the city. These mini pumping station with dewatering pumps will send the accumulated water on the road back to the river when there is waterlogging during the monsoon. The four ghats include Nimtala Ghat, Chandpal Ghat, Dilarjung Raod Ghat and Chandpal Ghat (adjacent to Millenium Park). The proposal for setting up these mini pumping stations has already been approved by the board of engineers and sent to Mayor Sovan Chatterjee for his final approval. Also Read – Heavy rain hits traffic, flights”We have witnessed that waterlogging takes places in areas , which are adjacent to the river, during monsoons. This is because the lockgate of the river is closed for more than five hours during high tide and if there is heavy rain, the accumulated water cannot drain into the river. The dewatering pumps will be used to channelise this water back into the river,” a senior official of KMC’s drainage department said.There are presently 18 lockgates connected to the river as well as the Tolly Nullah popularly known as Adi Ganga which is closed two hours prior to the time of high tide and is opened again two hours after the completion Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedof the high tide.”We will first examine the effectiveness of these dewatering pumps and go forward in developing the infrastructure at every points where there are lockgates in the city,” the official said.It may be mentioned that the efforts taken by the KMC’s drainage department has brought about a noticeable improvement in the condition of the city during monsoons. There has been a constant upgrade of technology and setting up of infrastructure for a complete overhaul of the drainage system.Mayor Sovan Chatterjee claims that the situation in Kolkata during monsoons is far better than cities like Mumbai, Delhi, Nagpur, Ahmedabad etc. “Even when there is rainfall above 120 mm, there was accumulation of water in some pockets but water drained out at a very rapid pace,” an official of KMC’s drainage department said.last_img read more

WB govt working on ease of delivering services Sen

first_imgKolkata: After winning laurels from the World Bank on ease of doing business, the West Bengal government was now trying to create ease of delivering services, additional chief secretary, IT and Electronics department, Debashis Sen said on Wednesday. “West Bengal is now among top 10 states in India on ease of doing business as notified by the World Bank. The state is now working on ease of delivering services”, Sen said at the Calcutta Chamber of Commerce here. Also Read – Bose & Gandhi: More similar than apart, says Sugata Bose He said the state government was also laying emphasis on blockchain, artificial intelligence, internet of things and quantum computing as well. “Ease of delivering services will be done using technology with minimal touch points with the government”, Sen said. Methods of government procurement is also going to change in a big way by promoting competition, the additional chief secretary said. West Bengal has also earmarked 200 acres for setting up a silicon valley hub, he said.last_img read more

When Padma Shri danseuse enthralled Delhi

first_imgA performer, educator, choreographer, arts administrator, author and a cultural visionary; when Prathibha Prahlad performs, the viewers are left spell-bounded. Recently, the Padma Shri awardee did the same magic when she dedicated her performance to Lord Krishna at the Stein Auditorium, India Habitat Centre. The first performance was, ‘Vande Vasudevam’, which described the beauty of Vishnu ‘s face and form. The velour of this beautiful God who rides the Garuda, and killed the crocodile who tried to pull in Kariraja – the brave elephant, were depicted by Prahlad in every expression and move. Also Read – Add new books to your shelfThe second performance was ‘Saama Gana’ – this piece with rhythmic interludes elaborates on the birth of Krishna in Kansa’s prison and his father Vasudeva taking him in the middle of the night to Gokula and leaving him at Nanda’s place.The third performance by Prahlad was ‘Kaun Radhika – Darbari Raga /Adi Tala Rukmini’. Krishna’s wife wonders who Radhika was and why Krishna was so enamoured with her. Fourth performance was ‘Mangalam – Jo Mukunda’ – a lilting lullaby putting child Krishna to sleep. On this occasion, Carnatic vocalist and composer Sudha Raghuraman were on vocal, G. Raghuraman was on flute, Tanjavur Kesavan was on Nattuvangam and MV Chandrashekar was on mridangam.last_img read more

Man held by Cyber Crime police for duping of Rs 14L

first_imgKolkata: A person identified as Nepal Mondal of Swarupnagar in North 24-Parganas has been arrested at the Bidhannagar Cyber Crime police station for allegedly duping a person in the name of providing companions for friendship.The complainant identified as Rafiqul Islam of Kaliachak in Malda was duped during the year 2017. On September 12 in 2017, Islam approached the Bidhannagar Cyber Crime police station and stated that he has been duped of Rs 1.4 lakh by some people. He informed he had received some SMS from a bulk SMS service provider’s number stating that they would arrange companions for friendship. It was mentioned in the SMS that the customer will also get the chance to earn good amount of money. Also, a website address was also provided ( Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataIslam contacted on the mobile number given in the SMS. According to Islam, a lady picked up his call and identified herself as Mini. She provided Islam another mobile number on which he used to call. He alleged that after he was convinced about the friendship, the said woman allegedly asked Islam to provide money, unless she will not interact. Initially Islam gave some money to a bank account number, which was given by the woman. But as the process continued in phases, Islam credited Rs 1.4 lakh total in three phases. Later, he realised that he has been duped and approached the police. Also Read – Lightning kills 8, injures 16 in stateAs Islam did not called the woman for quite a few days, the accused persons smelled something fishy and switched off all the mobile phones. Thus, the police was not able to trace them since the complaint was lodged. But, all the mobile numbers were being placed in the tracking system. A few days ago, police officers saw that a mobile handset has been activated. Immediately while searching for the address, sleuths came up with Mondal’s name. On Wednesday, Mondal was arrested from his home in Swarupnagar.last_img read more

How to match right footwear with right outfit this monsoon

first_imgMonsoon is a gloomy time of the year that is generally a threat to all the fashion fun. Matching a right footwear adds to the dilemma. From light material to light shoes and from rich hues to comfortable feet, experts suggest ways to give this monsoon season a fashionable twist.Experts list down ways to look fashionable this monsoon.4Gold foil prints with strapy sandals: Monsoon season calls for light material and pastel shades, and if you add a touch of shimmer with beautiful gold foil prints on your pastel coloured kurtas, you’re effortlessly ready for the monsoon. You can chose from a variety of colours like turquoise, dust pink, teal blue or bright pink. Also Read – Add new books to your shelfAs for your feet, prefer wearing flats or platform heals instead off pencil heel to avoid slipping and other walking discomfort due to mud and puddles during the monsoon season. So pair your gold foil printed kurtis with strappy flat sandals and it would definitely ace up your style game.4Vibrant colours to make gloomy days exciting: you can change the fashion game by bringing in all the vibrant and exciting colours out of the wardrobe. Vibrant colour outfits would instantly add up to your entire look without having to do much accessorising, just team it with your pair of ballerina shoes. Also Read – Over 2 hours screen time daily will make your kids impulsive4Layering especially quilted jackets: Mix and match works wonders and this monsoon calls for some mixing and matching of different colours and prints. Why always go for the boring light shades and dull layering? Put some maroon slim pants with a black indie top and to layer it up some ethnic print quilted jacket for a boho chic vibe even in monsoon. Buy some bright hues to cover your monsoon blues. Team up your outfit with a pair of clogs or a pair of cute flip flop during monsoon which can never go out offashion.last_img read more