Conventional printed circuit board. Penn Theorists to Create Optical Circuit Elements (PhysOrg.com) -- "If you open up almost any electronic gadget, you will see various elements that operating using electric circuitries," Nader Engheta tells PhysOrg.com. "Many of them have different functionalities, such as inductors, capacitors, resistors, transistors, and so forth. These well-known elements have been around for decades. But what if you could bring these concepts to the nanoscale, and what if they could operate with light instead of electricity?" 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: Running electronics using light (2009, October 19) retrieved 18 August 2019 from https://phys.org/news/2009-10-electronics.html Explore further Engheta, a scientist at the University of Pennsylvania, along with Andrea Alů, believe that it is possible to create a nanoscale circuit board that has the potential to be useful in communications. Engheta and Alů describe their concept of an optical nanoscale circuit in Physical Review Letters: "All-Optical Metamaterial Circuit Board at the Nanoscale.""If you go to the nanoscale," Engheta explains, "you would have to conceive of nanoparticles that effectively act like the elements seen in current devices. It would be necessary to create nanoparticles of a specific shape, and made from specific materials, that would allow them to act as capacitors, resistors, and other well-known elements."There are three main advantages of using optical nanoparticle circuit boards, Engheta says. First of all, being able to further miniaturize various communications devices would ensure that technology continues to evolve. “We are moving toward having more and more information compacted into a smaller volume.” The second advantage is that using optical frequencies would provide more bandwidth. Finally, there is a very real possibility that nanoscale circuit boards, properly constructed, would use less energy. “We have to look more into this possibility, but it is quite likely that optical nanoparticle circuit boards would be low energy in nature,” Engheta insists.So far, Engheta and Alů have only used computer simulations to test their ideas related to nanoscale circuit boards. The Engheta group is, however, working toward an experimental realization of their theories with a proof of concept for lumped circuit elements. “What we’ve come up with is compatible with the nanofabrication techniques already in use today,” Engheta says. “We are in the midst of trying to construct some nanowires to serve as our proof of concept for lumped optical circuit elements, and hopefully we’ll see some results in the next six months or so.”One of the biggest challenges to realizing this type of nanoscale circuitry is that it is difficult to form the structures needed at such a small size. “Additionally,” Engheta admits, “we would have to put these structures next to each other in specific patterns. This is doable, using present nanofabrication techniques, but not easy.” The fabrication process would include creating structures out of metamaterials and a process that imitates the electronic circuitry we are more familiar with. “One of our ideas is to cut a groove in the material, one that could contain the light used in the circuit board, to connect nanoparticles together. It would be similar to the way wires connect various elements in electronic devices.”Once a proof of concept is realized for this circuit board, Engheta hopes to take optical nanocommunications to another level. “We are extending our concept to other elements that are non-linear,” he says. “This could allow us to develop switches, opening the door to computation.”More information: Andrea Alů and Nader Engheta, “All Optical Metamaterial Circuit Board at the Nanoscale,” Physical Review Letters (2009). Available online: link.aps.org/doi/10.1103/PhysRevLett.103.143902Copyright 2009 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.
Fuller et al. propose a model for the synthesis of heavy elements in which a rapidly rotating neutron star is swallowed from the inside by a tiny black hole. The centrifugally deformed star, shown in cross-section, sheds considerable mass at its equator as it spins up and angular momentum is transferred outward. Heavy atomic nuclei, including gold and platinum, can form via the r-process in the neutron-rich matter that’s expelled from the imploding star. Credit: APS/Alan Stonebraker, via Physics Citation: New theory suggests heavy elements created when primordial black holes eat neutron stars from within (2017, August 24) retrieved 18 August 2019 from https://phys.org/news/2017-08-theory-heavy-elements-primordial-black.html Space scientists are confident that they have found explanations for the origins of light and medium elements, but are still puzzling over how the heavier elements came to exist. Current theories suggest they most likely emerged during what researchers call an r-process—as in rapid. As part of the process, large numbers of neutrons would come under high densities, resulting in capture by atomic nuclei—clearly, an extreme environment. The most likely candidate for creating such an environment is a supernova, but there seem to be too few of them to account for the amounts of heavy elements that exist. In this new effort, the researchers offer a new idea. They believe it is possible that PBHs occasionally collide with neutron stars, and when that happens, the PBH becomes stuck in the center of the star. Once there, it begins pulling in material from the star's center.PBHs are still just theory, of course. They are believed to have developed shortly after the Big Bang. They are also believed to roam through the galaxies and might be tied to dark matter. In this new theory, if a PBH happened to bump into a neutron star, it would take up residence in its center and commence pulling in neutrons and other material. That would cause the star to spin rapidly, which in turn would fling material from its outermost layer into space. The hurled material, the researchers suggest, would be subjected to an environment that would meet the requirements for an r-process, leading to the creation of heavy metals.The theory assumes a certain number of such collisions could and did occur, and also that at least some small amount of dark matter is made up of black holes, as well. But it also offers a means for gathering real-world evidence that it is correct—by analyzing mysterious bursts of radio waves that could be neutron stars imploding after internal consumption by a PBH. Explore further Primordial black holes may have helped to forge heavy elements Journal information: Physical Review Letters
Journal information: Proceedings of the National Academy of Sciences Three-dimensional shapes fill physical space in a certain way. If you pour marbles into a jar, the marbles will randomly pack within the jar. If you carefully placed every marble, layer-by-layer in the jar such that the marbles in one layer sit within the crevices between marbles on the layer below it, you can pack a few more marbles in the jar than if it was randomly packed. This will give you the highest density packing, or the least amount of space between particles. 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: Close-packing rules may not guide nanoparticle self-assembly after all (2018, January 29) retrieved 18 August 2019 from https://phys.org/news/2018-01-close-packing-nanoparticle-self-assembly.html Explore further Cersonsky et al. found that in all of polyhedral systems that they studied (FCC, SC, and BCC) the packing density was greater than the random close-packing density, which was greater than the minimal density for self-assembly. This result shows that spontaneous order does not occur because of a packing mechanism and that these systems cannot be ordered by packing. In other words, packing rules are not necessarily predictive of the ideal shapes for self-assembly even though the dense packing structure is the most thermodynamically stable structure.This paper looked at nanoparticles that were not confined. According to Greg van Anders, assistant professor of physics and co-author of the paper, "We expected that we would find that colloids would order by packing. Instead, we found that they don't. This is particularly surprising because particles don't pack even when the structures they form are so-called 'close-packed' structures."Usually in materials science, packing rules are used to predict the optimal shape for a nanostructure, but given these results, the question becomes if, and when, packing rules can be used to predict the thermodynamically optimal shape for self-assembly.There is still some correlation between packing shape and optimal particle shape, and therefore, packing shape may be helpful in guiding predictions, but ideal packing shapes should not be the goal in nano-structure assembly. Dr. van Anders points out that this is actually good news for people trying to synthesize polyhedral nanoparticles that self-assemble into nano-structures:"After we found that the mechanism that drives the formation of structure is not packing, we realized that this might mean that perfectly-shaped particles, which pack most densely, but can be technically challenging and expensive to make, might not be the ideal shape for target structures." More information: "Relevance of packing to colloidal self-assembly" Rose K. Cersonsky, Greg van Anders, Paul M. Dodd, and Sharon C. Glotzer, Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1720139115 , On Arxiv: https://arxiv.org/abs/1712.02473 Linus Pauling applied this idea of packing density to ions, and proposed that packing principles lead to the formation of crystal structures. Nature does not like empty space, so particles should pack in the highest density or close-packed formation. In the field of materials science, colloid crystals and nanoparticle superlattices form via self-assembly of small particles in which the particles form a thermodynamically stable structure. The structures nanoparticles form are very often those found in conventional metals: face-centered cubic, simple cubic, and body-centered cubic.The theory is that packing principles guide the self-assembly of colloidal crystals. However, researchers from the University of Michigan have shown that the ordering mechanism for colloid crystals does not cause particles to self-assemble. Instead crystal assembly and packing are correlated, not causal. Furthermore, they show that packing principles may not be the best prediction tool for colloidal crystal shape. Their work appears in The Proceedings of the National Academy of Sciences.In self-assembly, a thermodynamically stable structure is formed. This structure minimizes free energy. For colloids, this frequently happens when entropy is at a maximum. However, when studying the mechanisms that guide self-assembly, researchers look at what happens at extreme conditions. At very high pressures, rather than maximizing entropy, hard particles will maximize density.To investigate the fundamental question of whether packing principles guide self-assembly, Cersonsky, et al. used modeling methods to compare three different density terms. The first is the self-assembly density, which is the lowest density where self-assembly is observed. The second is packing onset density. As the name implies, this is the lowest density where packing behavior is observed. The third term is the random close packing density, which is the maximum density that the system can be found in a disordered state.When looking at mathematical models at very high pressures (i.e., infinite pressure), there should be a boundary at which particles being to pack. The authors tested for this boundary using Maxwell relationships to define packing onset density. If the self-assembly density is found to be approximately equal to the packing onset density, then packing is likely guiding self-assembly. However, if the self-assembly density is less than the packing density, then something other than packing rules guides self-assembly. Furthermore, packing density is compared to the random close-packing density. , arXiv How particles pack in a confined space © 2018 Phys.org Shape Family and Structures. The authors rely on a previously defined parameterization (A) which continuously maps two values, α3 and α4, to convex polyhedra. This parameterization, here known as the ∆423 family, contains the space-filling shapes for (B) FCC, (C) SC and (D) BCC. Credit: Rose Cersonsky et al., arXiv:1712.02473 [cond-mat.soft]
She has been regaling audiences in various parts of the country for quite some time now. Recently, music lovers in the Capital got a chance to listen to the dulcet tones of singer Rini Mukherjee. Rini recently gave an outstanding performance to enthral the audience with her melodious voice at Kamani Auditorium. The cultural event Sur Sangum was organised by Le Rythme in association with Engineers India Limited (EIL) and Pailon Group. The programme was jazzed up with Bharatnatyam by Padmashree Dr Saroja Vaidyanathan’s Ganesa Natyalaya followed by a performance by Rini. Also Read - 'Playing Jojo was emotionally exhausting'There were also iconic Bengali actor Saumitro Chattopadhyay and Bengali band from Kolkata Ebong Amra.Rini started with Devi Vandana and presented the golden melodies of Lata Mangeshkar and Asha Bhonsle along with songs from her own albums. The song Megha Chaye and Achena Akash was indeed impressive and regaled the audience. Rini is expecting to make her debut in Bengali playback singing very soon. During the occasion, the Chairman of Board for reconstruction for Central Public Sector Enterprise and former Revenue Secretary & Member of Parliament, Dr Nitish Sengupta released Swapnanil — Rini’s fourth Bengali music album. Delhi chief minister Sheila Dikshit also sent her a message wishing the album all success. The album is an assortment of modern Bengali songs of different moods with unique composition.
Art Spice Gallery, in alliance with the Turkish Embassy celebrates the culture and tradition of Turkey, on the occasion of Turkey’s National Day using the truly deserving and rewarding medium of art. This stellar show is also supported by luxury lifestyle store, Craft House and Turkish Airlines .Bridging the glorious heritage of both India and Turkey, this show titled - On the Edge of the City - has been conceived by Art Spice gallery to display the beautiful and daunting works of award-winning Turkish artist, Serdar Leblebici. Also Read - 'Playing Jojo was emotionally exhausting'The exhibition will showcase a series of work inspired from a novel, Cemile, which was written by Orhan Kemal (15 September 1914 – 2 June 1970), who has a unique place in the modern Turkish literature with his novels and stories, and read by the artist in 2005. The initial works of the series titled On the Edge of the City involves the years of 2005-2007. Approaching this subject once again in 2010, he painted it with a more colorful attitude compared to the first series. Also Read - Leslie doing new comedy special with NetflixThis novel emphasizes the challenging life struggle in Çukurova during the 1930s in the Turkish Republic established by Atatürk and the power of bonds keeping the individual alive in these challenging conditions.In total, 32 paintings produced by the artist with the technique of oil painting on canvas in different dimensions are exhibited at the exhibition. Each of his masterful works has enshrined within them a dazzling spectrum of emotions that tames even the most frigid of souls. Serdar’s images and portraits both inspire and shock you with their ethereal embodiment of the human spirit and his play of colours not only darkens the shadows, but highlights them as well. This exhibition also has the characteristics of a reverence due to the 100th birth anniversary of Orhan Kemal, who died in 1970.Head over to explore the genius of Serder Leblebici reflected in his engaging and daunting works.WHERE: Art Spice Gallery, Metropolitan Hotel WHEN: 18 to 31 October
Kolkata: The Durga Puja organisers in the city have joined their hands for a noble cause bringing in more than 1,500 people under one umbrella to donate blood. As many as 1,526 people donated blood at the blood donation event organised at Khudiram Anusilan Kendra under the banner of Forum for Durgotsav that presently has 300 puja committees under its aegis. The initiative of the forum assumes significance as blood donation camps across the districts are a few with the summer days setting in and the political personalities getting involved in campaign for Panchayat election. State Power minister Sobhandeb Chattopadhyay, Minister of State for Health Chandrima Bhattacharjee, Minister of state for Tourism Indranil Sen and Bidhannagar MLA Sujit Bose attended the camp. Also Read - Heavy rain hits traffic, flights "We had started a campaign on social media as well as through banners and hoardings for the last few months. Our target was to collect 1,500 units of blood for donation. We are happy that we have surpassed our target with 1,526 people coming forward for the noble cause," said Sandipan Banerjee, vice-president of the Forum. There was a unique gift for all the donors who were handed over VIP passes for 300 pujas of Durga Puja in 2018. There are nine leading blood banks in the city and the districts who will store the blood collected from the camp.
In India, roller technique of painting is not in vogue and rarely is it used as a way of painting at the recognizable level in art market. But some artists still do it and some among them coming are out with a new formula. Purnendu Mandal is one such artist who does painting with roller technique in impressionism form and he gets pat from art fraternity for his style of work as his evolved style of work in impressionism is risky and always demanding. Aesthetic Memories (A journey Through art) 12th Solo art exhibition by Mandal which will be held at the All India Fine Arts andCrafts Society(AIFACS), Gallery No-B, 1, Also Read - 'Playing Jojo was emotionally exhausting'Rafi Marg in the Capital from March 17 to 23.Mandal is not a very senior artist but his paintings catch the eyes of senior artists from India and other countries. Born and brought up in Malda District of West Bengal, Purnendu comes out with a very fine sense of art coupled with his hard work which impresses every one. Studying fine art at Government College of Art and Craft, Kolkata, Purnendu Mandal wandered here and there for gathering the various kind of information which can’t be acquired at a college or school. Also Read - Leslie doing new comedy special with NetflixWhen he found satisfaction from his extensive roaming he started doing painting in a serious manner. Later, in course of time he evolved his own style and method of work which he still follows while doing different kind of paintings on various subjects. Purnendu Mandal is an expert of impressionism form of paintings. His emphasis on impressionism and its vivid norms reveals the relevant aesthetics and the desired standards of glory in each work that is unique in its own way. His impressionism form is not exactly the same form of conventional but gets mould from the artist to give refined impression. His ‘impressionist’ style and outlook is clearly evident in the work through thin yet visible brush strokes, openness of compositions, and emphasis on accurate depiction of light in the changing qualities over a passage of time, normal subject matter and inclusion of movement as an important element of human perception through vivid angles. Where: All India Fine Arts and Crafts Society(AIFACS), Gallery No-B, 1, Rafi Marg When: March 17 to 23
Kolkata: Amid continuing agitation at the tea gardens in north Bengal and an ongoing three-day strike over minimum wage, planters on Thursday appealed to the unions to call off the protest programmes and allow normalcy to be restored. A tripartite meeting was held on Monday in Siliguri where the state Labour Department officials outlined the progress on the issue of minimum wage. The Joint Forum of Trade Unions, an umbrella organisation of trade unions working in the tea sector, however, called the strike after the meeting to negotiate their demands on minimum wage turned out to be inconclusive. According to planters, the tea industry in north Bengal's Dooars and Terai regions have already suffered substantial production losses during the peak season in 2018 due to frequent gate meetings in the first and second week of July. Darjeeling's tea industry, which is in recovery mode after suffering huge losses to the tune of around Rs 500 crore in 2017 due to the 105-day strike, is in "no position to bear any further disruptions". "Therefore, unless normalcy is restored immediately, the production and productivity would decline further," the Consultative Committee of Plantations Association (CCPA) said in a statement. Tea producers also reiterated that the industry in West Bengal is "under severe financial stress" as tea prices over the last many years have remained stagnant and have not kept pace with the rising cost of production. "Unless price realisations and productivity improve, the industry cannot sustainably implement any further enhancement of wage. Moreover, disruptions by way of strikes and gate meetings would aggravate the situation further and make it extremely difficult for the industry to recover on the production front as well as in sustaining the expected quality of Tea made and obligations of payments in future," the statement said. Planters also said it has to be appreciated by all stake holders that the finalisation of minimum wage is only possible after conclusion of the ongoing discussions of the Minimum Wage Advisory Committee and submission of the committee's recommendations to the state government. As many as 11 meetings of the Minimum Wage Advisory Committee have already been held. The next meeting is scheduled to be held on August 20. Tea planters said the government has offered to examine all the pressing issues at the next meeting. Usually, wage agreement for tea workers is executed for a three-year period and the last agreement had expired on March 31, 2017. In fact, West Bengal government proposed an interim hike of Rs 17.50 to increase the remuneration from Rs 132.50 to Rs 150 with effect from January 1, 2018. Unions had protested against the "minuscule hike" in the interim measure. The state also introduced interim payment of compensation on account of savings on the procurement cost of food grains at the rate Rs 9 per day per worker from May 1, 2018.