Smooth operators Teflon microfluidic chips

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. (PhysOrg.com) — The growing number of research and development efforts focused on microfluidics speaks to the technology’s promise of a potentially broad range of applications, largely in highly-integrated single-chip medical devices. However, the materials currently used to fabricate these labs-on-a-chip and other microfluidic devices have significant limitations, including absorption of small nonpolar and weakly polar molecules, adsorption of biomolecules, and the material’s molecules leaching into the microfluidic channel. The good news is that researchers have overcome these obstacles using microfluidic channels made entirely of Teflon, which supports cellular activity similar to that found in current materials. Moreover, whole-Teflon microchannels have gas permeability levels that permit cells to be cultured in-channel for extended periods of time. Overcoming these two obstacles led to the team’s two key innovations, micropatterning Teflon materials and bonding Teflon chips. “We established a very simple and easy-access method to fabricate three-dimensional Teflon micro- and nanostructures. The Teflon PFA and FEP substrates we used are melt-processable, so they could be hot-embossed using a template – an ideal way is to generate micropatterns in photoresist and then transfer the structure into the mold.”But another problem arose. “Teflon’s melting points of substrates are much higher than those of photoresist. We therefore introduced a specially-treated intermediate thermosetting master to overcome the gap between low-melting-point photoresist master and a high-melting-point replica, allowing us to cast the master at milder temperatures into the replica and then use it at elevated temperatures to mold the patterns into Teflon.”Their method was adapted from traditional soft-lithography, which previously wasn’t applicable to high-melting-point substrates. “Normal PDMS severely leaches gas above 150 °C, creating bubbles that make it impossible to mold micropatterns into Teflon. With our treated PDMS replica, we now can mold any micropatterns that are formed in photoresist by photolithography into thermoplastics (including Teflon) at as high as 350 °C.”The team also designed a very simple and highly efficient method that solved the problems that have been encountered for a long time when bonding Teflon chips. This thermobonding process is based on different thermal expansion factors of Teflon materials (slightly higher than that of stainless steel) and the holding scaffold (stainless steel screw clamps) during bonding. “The bonding pressure is automatically controlled,” Wu explains. “When temperature is raised and the two Teflon plates are not bonded, Teflon expands more than the clamps and so the pressure is high. Once the two plates are bonded, the pressure is automatically released.”Wu is already looking at future innovations and improvements. “We want to develop a smaller on-chip microvalve. The current nanoliter valve is still relatively large, so we’re working on reducing its volume to the picoliter range.” The team is also interested in advances in Teflon itself. “The optical transparency of our current whole-Teflon chip is still lower than that of PDMS and glass chips, so optical detection can be performed only when the optical path length of the Teflon chip is less than 2 mm. If the Teflon materials become as transparent as PDMS or glass, we will have more freedom in designing the microchips. But,” he acknowledges, “this depends on the design of new Teflon materials.”In terms of the new chip’s most promising near-term and future applications, Wu comments that “since the whole-Teflon device is extremely inert and super-clean, it is superior for applications involving corrosive chemicals, strong solvents, high and low temperatures, and pressurized processes. It is antifouling and biocompatible, and therefore well suitable for quantitative and biological analysis. Interestingly, various biological cells can attach and grow well inside the Teflon channels – so it expands the applications of microfluidics to all these areas that were previously difficult. It is particular advantageous when accurate quantitative information is required.”Beyond this Wu sees an even wider range of possibilities. “We also believe that Teflon materials are superior to PDMS for commercial applications of microfluidics due to their outstanding stability and reliability. Teflon could be a next-generation microchip material with very broad use, such as serving as standard equipment for flow reactors, microanalysis and bioassay. Moreover, they can also be used under extreme conditions – for example, on a space shuttle.”Perhaps the ultimate application of Wu’s Teflon microfluidic technology will derive from the intersection of further miniaturization and biocompatibility. “We can mold Teflon pattern down to submicron range and fabricate sealed Teflon channels within the scale of 10 um. Since Teflon materials have outstanding biocompatibility and have long been used for implantations in human body, such as catheters, miniaturized Teflon microfluidic devices might be used for in-vivo diagnostics, drug delivery and flow control.” Citation: Smooth operators: Teflon microfluidic chips (2011, May 17) retrieved 18 August 2019 from https://phys.org/news/2011-05-smooth-teflon-microfluidic-chips.html Explore further Lawsuit filed against Teflon maker DuPont More information: The researchers, led by Prof. Hongkai Wu at Hong Kong University of Science and Technology’s Department of Chemistry, faced a number of obstacles to designing and developing a microfluidic chip that was optimally inert yet suitable to machining. “Currently, there are two major types of materials for microfluidic chips,” Wu explains to PhysOrg.com. “One is inorganic, such as glass and silicon. Unfortunately, fabrication of micropatterns and bonding chips of these materials are difficult and require sophisticated equipment. The other class of materials is plastics, including polydimethylsiloxane (PDMS) – the most widely-used – poly(methyl methacrylate) (PMMA), and polyurethane. Chips in plastics are easier to fabricate than in glass, but they have their own problems,” including the adsorption, absorption and leaching mentioned above, as well as being incompatible with organic solvents, all of which greatly limit their microfluidic chip applications. “For example,” Wu continues, “they will be unsuitable for highly-sensitive analysis because the analyte will be lost by absorption if it’s a small, non/weakly polar molecule or by adsorption on channel walls if it’s a large molecule. For all of these reasons, we chose Teflon, which is well-known for its high degrees of inertness, non-adhesiveness and resistance to solvents.” Moreover, the Teflon compounds Wu used – perfluoroalkoxy (PFA) and fluorinated ethylenepropylene (FEP) – have melting points above 260 °C (one of the highest in thermoplastics) and are optically transparent (although less so than PDMS and glass). At the same time, Teflon had its own challenges. For example, Wu notes, “Teflon’s superior inertness causes two major obstacles: one in micropatterning the material and the other in bonding patterned chips. Prior to our work, there were only several very expensive and complicated lithographic methods using high-energy radiation to effectively micropattern Teflon.”In addition, Wu continues, “tight bonding of Teflon chips is rather difficult. Both bonding temperature and pressure need to be precisely controlled to overcome the problems that come from residue internal stress and plastic flow. “Initially we tried to bond the Teflon channel without pressure (as for bonding glass chips) and with constant pressure (as for bonding PMMA chips),” says Wu, “but neither worked. We needed an effective and convenient method to bond and thereby seal the Teflon channels.” Fig. 1. Molding of Teflon microchannels using PDMS masters. (A, B) Schematics of the preparation of thermally stable PDMS masters and the molding of Teflon channels, respectively. (C-E) SEM images of microfabricated PFA channels (C) for droplet generation that includes a micromixer (D) and a 3-D spout (E). (F) Microchannel with a rounded profile molded from a reflowed positive photoresist (AZ4903) structure. (c) PNAS, doi: 10.1073/pnas.1100356108 Copyright 2011 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. * Whole-Teflon microfluidic chips, PNAS Published online before print May 2, 2011, DOI:10.1073/pnas.1100356108* Department of Chemistry, Hong Kong University of Science and Technologylast_img read more

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Energyharvesting shock absorber that increases fuel efficiency wins RD 100 award

first_img Explore further Citation: Energy-harvesting shock absorber that increases fuel efficiency wins R&D 100 award (2011, July 14) retrieved 18 August 2019 from https://phys.org/news/2011-07-energy-harvesting-absorber-fuel-efficiency-award.html The shock absorber harvests energy from vibrations experienced by a vehicle’s suspension system into electricity that can charge the battery and power vehicle electronics. Image credit: Lei Zuo More information: Prof. Zuo’s handout and R&D 100 awardsvia: Asian American e-Zine An energy-harvesting shock absorber that can be installed in a vehicle’s suspension system to absorb the energy from bumps in the road, convert the energy into electricity, and improve fuel efficiency by 1-8% has recently won the R&D 100 award. Nicknamed the “Oscar of Invention,” the annual award is given out by R&D Magazine to recognize the top 100 innovative technologies introduced during the previous year. Previous winners have included the ATM (1973), liquid crystal display (1980), Nicoderm anti-smoking patch (1992), lab on a chip (1996), and HDTV (1998). © 2010 PhysOrg.com The new shock absorbers were designed by Professor Lei Zuo and graduate students Xiudong Tang and Zachary Brindak at the State University of New York (SUNY) at Stony Brook, with funding from the New York State Energy Research and Development Authority (NYSERDA). The development joins regenerative braking and other techniques that address the vast amount of energy wasted by vehicles. Although transportation accounts for 70% of oil consumption in the US, only 10-16% of the fuel energy is used to drive the car – to overcome road resistance and air drag. The rest is lost due to braking, vibrational energy dissipation, exhaust heat, and other inefficiencies.Zuo’s team developed and patented two different types of shock absorbers: linear and rotational. The new linear shock absorber consists of a small magnetic tube with high flux intensity that slides inside a larger, hollow coil tube. The rotational version employs a compact motion magnification mechanism. Due to bumps and vibrations from normal driving, the sliding tubes or rotating generator can produce an electric voltage. When installed in a medium-sized passenger car traveling at 60 mph, the shock absorber can generate 100-400 watts of energy under normal driving conditions, and up to 1600 watts on particularly rough roads. Trucks, rail cars, and off-road vehicles get a return of 1-10 kilowatts, depending on road quality. The harvested energy is then used to charge the battery and power the vehicle’s electronics, which is typically 250-350 watts with optional electronic systems turned off. This energy reduces the load on the vehicle’s alternator, which usually has a capacity about 500-600 watts. In this way, the harvested energy could increase fuel efficiency by 1-4% in conventional cars and by 8% in hybrid vehicles. As a side benefit, the shock absorber also creates a smoother ride due to the ability to adjust the suspension damping and implement self-powered vibration control. The electricity-generating shock absorber can be retrofitted into today’s vehicles by replacing conventional shock absorbers – in which the vibration energy is wasted as heat – without modification of the vehicle suspension structure. The researchers estimate that the installation cost can be recouped in 3-4 years for typical passenger vehicles, and 1-2 years for trucks.“If just 5% of the 256 million registered vehicles in this country adopt this technology, we will create a market of over six billion dollars,” said Zuo in a press release. “The total energy we can recover per year from the suspensions is more than the amount produced by the Niagara Falls Power Plant.”Zuo added that the shock absorber is not yet commercially available, but the patent is ready for licensing. The researchers recently received a grant from the SUNY Technology Accelerator Fund to speed up commercialization. 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. Vehicle shock absorber recovers energy from bumps in the roadlast_img read more

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3G protocols come up short in privacy say researchers

first_img(Phys.org)—Researchers from the UK and Germany have found that 3G telephony systems pose a security weakness that results in threats to user privacy. The weakness makes it possible for stalkers to trace and identify subscribers. Their paper, “New Privacy Issues in Mobile Telephony: Fix and Verification,” says that 3G systems come up short in preventing unauthorized parties from tracking the physical location of users “We have shown that the protocols are vulnerable to new privacy threats and that these threats lead to attacks that can be mounted in practice at low cost.” 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. The authors, Myrto Arapinis, Loretta Mancini, Eike Ritter, Mark Ryan of University of Birmingham, and Nico Golde, Kevin Redon, Ravishankar Borgaonkar of Ttechnische Universität Berlin and Deutsche Telekom Laboratories, note a security timeline to 3G:When 3G protocols were first introduced in 1999, the possibility of an active attack was remote, partly because of the high cost of the equipment that would have been required and the lack of open source implementations of the protocol stack. The possibility is no longer remote. They said that cheap base stations can be produced by programming USRP (Universal Software Radio Peripheral) boards. “These lower the cost of producing radio devices thanks to software emulation of specialized functions once executed by expensive hardware.”The researchers said that devices’ physical locations could be identified at any time with relative ease, as the attacker does not need to know any keys, or to get involved with “fancy cryptography.” Instead, the weaknesses involve errors in the protocol logic.Encroachments on user privacy could range from personal stalking to worker harassment to other kinds of spy operations, to commercial profiling. The team tested phones on four networks and found they showed vulnerabilities. They tested networks of major operators T-Mobile, O2, SFR, and Vodafone. They showed that these were vulnerable to the researchers’ attacks. The authors propose fixes in the paper that use public key cryptography. “We used formal methods to show that the exposed privacy vulnerabilities could have been detected at design time. We developed and verified lightweight solutions to avoid the privacy vulnerabilities.”They noted that additional costs of using public-key cryptography are small. “The solutions we propose show that privacy friendly measures could be adopted by the next generation of mobile telephony standards.” Citation: 3G protocols come up short in privacy, say researchers (2012, October 11) retrieved 18 August 2019 from https://phys.org/news/2012-10-3g-protocols-short-privacy.html © 2012 Phys.orgcenter_img Experimental Attack Setup. Credit: Nico Golde et al. Briefs: InterDigital, Infineon team up 3G software Explore furtherlast_img read more

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Novel features of helium3 superfluidity discovered with new SQUID detector chip

first_imgPhase Diagram of Helium 3. Credit: ltl.tkk.fi/ The PTB sensor chip is ideal for obtaining low temperature NMR fingerprints of extremely thin helium-3 layers—essentially thin films. In addition to being able to discover new superfluid phenomena, the researchers hope to be able to investigate excitations at the surfaces of the various helium-3 phases known as Majorana fermions. A Majorana particle is a fermion that is its own antiparticle. These particles exist as quasiparticle excitations in superconductors and have recently been the focus of many intense research efforts. Journal information: Science (Phys.org) —In order to study many complex phenomena, physicists seek to isolate them in potential wells or boxes with easily described forms and boundary conditions. These features in turn dictate various behaviors of the system under study like, for example, equilibrium states or resonances. In recent times it has emerged that constraining particles on extremely small scales can result in interesting new behaviors. Artificial atom systems, like quantum dots, can be fine-tuned in this way to specific color or conductivity according to their dimension. In some cases, even the phase of a material can be manipulated. A group of researchers has recently demonstrated the ability to precisely control the phase structure of superfluid helium-3 by manipulating the geometry of the container that holds it, and applying an appropriate magnetic field. Their new paper, recently published in Science, describes how they used an ultra-sensitive SQUID detector to readout the NMR spectra that reveals the phase information. Citation: Novel features of helium-3 superfluidity discovered with new SQUID detector chip (2013, May 22) retrieved 18 August 2019 from https://phys.org/news/2013-05-features-helium-superfluidity-squid-detector.html Superfluidity has also found applications in high-energy physics and theories of quantum gravity, namely superfluid vacuum theory. The ultimate goal here is to develop a model that would unify quantum mechanics with gravity. For now, the researchers have plenty of experiments ahead to keep themselves busy. Improved sensor arrangements are expected to be able to resolve spatial features helium-3 films, which should in turn lead to new discoveries about superfluidity. PTB SQUID sensor chip (3 mm x 3 mm) is manufactured similarly to a computer chip in the semiconductor industry. Credit: PTB More information: Phase Diagram of the Topological Superfluid 3He Confined in a Nanoscale Slab Geometry, Science 17 May 2013: Vol. 340 no. 6134 pp. 841-844 DOI: 10.1126/science.1233621ABSTRACTThe superfluid phases of helium-3 (3He) are predicted to be strongly influenced by mesoscopic confinement. However, mapping out the phase diagram in a confined geometry has been experimentally challenging. We confined a sample of 3He within a nanofluidic cavity of precisely defined geometry, cooled it, and fingerprinted the order parameter using a sensitive nuclear magnetic resonance spectrometer. The measured suppression of the p-wave order parameter arising from surface scattering was consistent with the predictions of quasi-classical theory. Controlled confinement of nanofluidic samples provides a new laboratory for the study of topological superfluids and their surface- and edge-bound excitations. PTB SQUID sensor chip (3 mm x 3 mm) is mounted on a chip carrier. The SQUID chips are manufactured similarly to a computer chip in the semiconductor industry. Credit: Photo: PTB Superfluids: Observation of ‘second sound’ in a quantum gas With two protons, neutrons, and electrons, helium-4 has an overall spin of zero, and is therefore known as a boson. In the form of Bose-Einstein condensate, it shows just a single mode of superconductivity and superfluidity (a fluid that shows no viscosity). In contrast, helium-3 has a spin of plus or minus one half making it a fermion. Having a higher level of broken symmetry, helium-3 can support several varieties of superfluidity, which makes its phase diagram much richer. The simplest phase diagrams are pressure-temperature plots with equilibrium lines to indicate the state. Since helium-3 has nuclear spin of one half, it is affected by a magnetic field. The phase diagram of helium-3 can be extended to a third dimension representing the effect of a magnetic field. The phase boundary is then split between normal and superfluid components.The effect of reducing one of the walls of the container which holds the helium-3 is to change the preferred direction of the orbital angular momentum. When this dimension approaches the size of the Cooper pair coherence length, the superfluid state is suppressed in that direction, along with additional symmetry breaking. (The coherence length is the mean-square radius of a Cooper pair.) The phase of helium-3 can be described by an “order parameter,” which according to the standard Ginzburg-Landau formalism, expresses the free energy of a superconductor. The authors of the new Science paper were able to determine the order parameter from the line shape of the NMR spectra of helium-3. © 2013 Phys.org Explore further Other researchers had conducted similar investigations using NMR, however the signal to noise ration in the readout system limited the conclusions that could be drawn. The NMR also requires a significant magnetic field which complicates the effect of the magnetic field needed for manipulating the phase. Because of the small volumes involved, the magnetic fields used need to be low to prevent additional symmetry breaking. Typically, NMR instruments use a simple pick up coil to read out the LC circuit of the instrument. The new study used a SQUID device manufactured by Physikalish-Technische Bundesanstalt (PTB), which permitted a more sensitive detector to be built. 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

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Nanostructures enhance light trapping for solar fuel generation

first_img Wormlike hematite photoanode breaks the world-record for solar hydrogen production efficiency Illustration of a hematite photoelectrode consisting of a periodic nanobeam-array (red) on a conductive ITO layer (dark blue). The nanobeam structure boosts the absorption of sunlight at the hematite/H2O interface, resulting in more efficient conversion of sunlight into solar fuel. Credit: Soo Jin Kim, et al. ©2014 American Chemical Society (Phys.org) —As the world’s dependence on fossil fuels causes ever-increasing problems, researchers are investigating solar fuels as an alternative energy source. To make solar fuels, sunlight is converted into hydrogen or another type of chemical energy. Compared to energy produced by solar cells, which convert sunlight directly to electricity, solar fuels such as hydrogen have the advantage of being easier to store for later use. Because of the enormous amount of sunlight that reaches Earth, solar fuel generation has the potential to serve as a clean, terawatt-scale global energy source. But in order for this to happen, the photocatalysts that enhance light absorption and light trapping must be improved, both in terms of higher performance and lower cost. In a new study, researchers Soo Jin Kim, et al., at the Geballe Laboratory for Advanced Materials in Stanford, California, have demonstrated that photocatalysts made from iron oxide exhibit substantial performance improvements when they are patterned with nanostructures. Their paper is published in a recent issue of Nano Letters.”I think the most significant advance is that the work will provide valuable guidelines for the design of new, nanostructured photocatalyst materials capable of effectively absorbing light and driving catalytic reactions,” Professor Mark L. Brongersma at Stanford told Phys.org. “Hopefully, it will stimulate more research on photon management for photocatalyst materials. The use of photon managements in solar fuel generation is lagging behind strongly with respect to development of photon management strategies for solar cells.”As the researchers explain, iron oxide in the hematite phase (Fe2O3) is an earth-abundant semiconductor with a bandgap energy of 590 nm, which is considered close to optimal for water splitting and hydrogen production. Because it absorbs photons across a relatively large portion of the solar spectrum, it outperforms other catalyst materials that absorb smaller portions of the solar spectrum. Despite these advantages, hematite has a weakness: it cannot absorb photons near its surface, which results in many of the photoexcited carriers recombining rather than participating in chemical reactions to produce hydrogen. This problem occurs due to a mismatch between hematite’s very short (nanometer scale) carrier diffusion length compared to the absorption depth of light (micrometer scale near the surface). So even though the photons are present, they cannot be effectively used.Previous research has attempted to address this problem by adding metal nanostructures to enhance light absorption in the near-surface region of the photocatalysts. However, this approach suffers from intrinsic optical losses in the metal.In the current study, the researchers have circumvented this problem of optical loss by nanopatterning the hematite photocatalysts themselves. The nanostructures allow the photocatalyst to overcome the detrimental mismatch between the carrier diffusion and photonic absorption length scales, and redistribute the photons to the near-surface region. Nanostructuring’s benefits come from the fact that it allows sunlight to drive optical resonances in the hematite, resulting in an enhancement of both light absorption and light scattering. By engineering the size, shape, spacing, and dielectric environment of the nanostructures, the researchers could optimize and tune the resonant wavelengths across the solar spectrum.This strategy of nanostructuring a photocatalyst could be extended to other photocatalyst materials. As nanopatterning techniques continue to become used more often in many different areas, it is likely that nanostructured arrays can be made inexpensively over large areas.”Next, we are going to employ metamaterials concepts in our photocatalyst materials,” Brongersma said. “We will see where it takes us!” Journal information: Nano Letters Explore furthercenter_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. © 2014 Phys.org. All rights reserved. Citation: Nanostructures enhance light trapping for solar fuel generation (2014, March 24) retrieved 18 August 2019 from https://phys.org/news/2014-03-nanostructures-solar-fuel.html More information: Soo Jin Kim, et al. “Light Trapping for Solar Fuel Generation with Mie Resonances.” Nano Letters. DOI: 10.1021/nl404575elast_img read more

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Passive solar windows heat up in cold weather

first_img The scientists, led by Alexandre Dmitriev at the University of Gothenburg, along with coauthors from universities in Sweden, China, Iran, and the US, have published a paper on the solar thermal surfaces in a recent issue of Nano Letters.”We’ve developed a surprisingly simple, cheap, and effective way to transform regular glass windows into solar-powered heat-screens that could significantly change the thermal balance of living and working spaces, especially if one thinks of the ever increasing amount of huge glass surfaces used in modern architecture,” Dmitriev told Phys.org.The new surfaces are yet another application of nanotechnology, as the main functional components are plasmonic nanoantennas. The tiny antennas are made of nickel-aluminum oxide sandwiches, shaped like nanoellipses, and patterned as an array onto glass. With the help of electron oscillations, or surface plasmons, on the surfaces of these materials, the nanoantennas strongly absorb light, which heats the entire surface.In the new study the researchers demonstrated that, when sunlight shines on the surface, light is absorbed more efficiently from the front side (with the antennas) than the back side (the substrate). This directionality in light absorption makes the surfaces attractive for window applications, as sunlight can be absorbed most efficiently from the outside of the window. In addition, the surfaces are highly transparent, appear colorless, and almost completely preserve the color spectrum of sunlight.As the researchers explain, cold windows have a larger impact on heating a building than might be expected. This is because, when a person sits next to a cold window, the person radiates their body heat toward the window and the window acts like a “heat sink.” To compensate for this loss of heat, the indoor temperature needs to be increased to maintain a comfortable environment. As the new window surface can increase the temperature of the window by several degrees, it has the potential to offer a large energy savings.The researchers expect that the new surface may have other applications beyond windows. The nanoantennas are highly modular, can be “painted” onto any surface or, to preserve the directionality in absorption, can be directly transferred onto virtually any surface. They can also be manufactured out of a wide variety of materials, as well as tuned to absorb light of different wavelengths, which changes their color. “All of these advantages may lead to applications where transparency, directionality, and thermal properties are simultaneously important, with possibilities including radiative cooling, solar-powered thermal isolation, and others,” Dmitriev said. “These antennas might also potentially be coupled to molecular systems that are able to store sunlight as heat and release it on demand.”In the future, the researchers plan to work on achieving even larger temperature increases by enabling the surfaces to absorb ultraviolet and near-infrared radiation, which constitute a significant portion of solar radiation. More information: Gustav Jӧnsson et al. “Solar Transparent Radiators by Optical Nanoantennas.” Nano Letters. DOI: 10.1021/acs.nanolett.7b02962 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. (a) Artistic depiction of a nanoantenna surface. (b) Scanning electron microscope micrograph of the nanoantennas. (c) Photographs of the new surface held against a window. Credit: Jӧnsson et al. ©2017 American Chemical Society © 2017 Phys.org Explore furthercenter_img Journal information: Nano Letters Citation: Passive solar windows heat up in cold weather (2017, October 24) retrieved 18 August 2019 from https://phys.org/news/2017-10-passive-solar-windows-cold-weather.html Researchers have developed a way to transform ordinary windows into solar-powered heaters that use the sun’s energy to increase the window temperature by up to 8 K (nearly 15 °F) in cold weather. The researchers expect that the new solar thermal surfaces will lead to significant energy savings through reduced heating costs. Transparent solar technology represents ‘wave of the future’last_img read more

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Electrically tunable thirdorder nonlinear optical response in graphene

first_imgThe operation bandwidth of gate tunable THG ranged from ~ 1300 nm to 1650 nm, covering the most common spectral range for optical fibre telecommunications at 1550 nm. Such a broad operation bandwidth resulted from the energy distribution of the graphene Dirac fermions. The observation is similar to a parallel investigation published in Nature Nanotechnology to electrically control the THG efficiency (THGE) of graphene, likewise attributed to massless Dirac fermions. Overall, the experimentally observed broadband gate-tunable optical nonlinearities of graphene offer a new approach to build electrically tunable nonlinear optical devices in practice. Existing electronic interconnections (copper cables) for instance, suffer bandwidth loss due to performance restrictions, impeding accelerated information processing required for media streaming, cloud computing and the internet of things (IoT). A growing need exists to regulate light and develop compact, cost-effective, high-performance optical interconnects for higher bandwidth and lower loss. Future research efforts are likely to enhance the observed effects using a variety of approaches including waveguide/fibre integration and optical resonators. In addition, various polaritons and photonic metamaterials can provide localized enhancement and manipulation of optical nonlinearities in 2-D materials to create surface plasmons and tackle the foreseen challenges of nonlinear nanophotonics and nanophysics device development, with advanced optical solutions. The knowledge can be extended to other nonlinear optical processes in graphene, including high-order harmonic generation. The existing technology with traditional bulk crystals has hit a technical limit to realize the envisioned optoelectronic applications, due to their relatively small nonlinear optical susceptibility and the complex and expensive, fabrication and integration methods. The demonstrated nonlinear optical interaction enhancement in 2-D materials should ideally be developed alongside large-scale and high-quality 2-D material production, to enable completely different approaches for electrically tunable nanodevice construction. Such nanodevices may facilitate the proposed advances in metrology, sensing, imaging, quantum technology and telecommunications. Methods to enhance and manipulate nonlinear optical responses in 2D materials: a) photonic crystal cavity, b) microdisk resonator, c) electrically tunable microring resonator, d) plasmonic structure. Red arrows = input photons, blue and green arrows = photons generated at different frequencies. Credit: Nature Photonics, doi: 10.1038/s41566-018-0201-9. Tunable third harmonic generation in graphene paves the way to high-speed optical communications and signal processing 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. , Nature Nanotechnology The research focus on 2-D materials has intensified with its potential to modulate light for superior performance and realize applications that can enhance existing technologies. Graphene, the best known 2-D material, derived from 3-D graphite, constitutes a monolayer of carbon atoms arranged in a 2-D hexagonal lattice, exhibiting strong ultra-wideband light-matter interactions, able to operate at an extremely broad spectral range, suited for next-generation photonics and optoelectronic devices. The unique electronic properties of graphene originate from Dirac cones, features in electronic band structures that host charge carriers of zero effective mass, so-called massless Dirac fermions that occur in 2-D materials. Materials scientists are currently at a stage of experimental infancy to realize many interesting properties of the nonlinear optical responses of graphene, to aid its promise to disrupt existing technology and facilitate wide-ranging applications. Schematic representation of the multiphoton effects in graphene Dirac fermions: the increase of chemical potential |Ef| can successfully switch off one-photon (|Ef| > 1/2ħω0), two-photon (|Ef| > ħω0), and three-photon (|Ef | > 3/2ħω0) interband transitions by Pauli blocking. Two-photon interband transitions contribute to third-order nonlinear optical susceptibility [χ(3)] positively, while one- and three- photon interband transitions contribute negatively. Red arrows indicate the input photons at ω0 frequency and the blue arrows indicate the generated third-harmonic photons at 3ω0 frequency. ħ, reduced Planck constant. Credit: Nature Photonics, doi: 10.1038/s41566-018-0201-9. Citation: Electrically tunable third-order nonlinear optical response in graphene (2018, August 1) retrieved 18 August 2019 from https://phys.org/news/2018-08-electrically-tunable-third-order-nonlinear-optical.html More information: Gate-tunable third-order nonlinear optical response of massless Dirac fermions in graphene www.nature.com/articles/s41566-018-0175-7 Jiang et al, 21 May 2018, Nature Photonics.Electrically tuned nonlinearity www.nature.com/articles/s41566-018-0201-9 Zhipei Sun, 28 June 2018, News & Views, Nature Photonics.Generation of Optical Harmonics journals.aps.org/prl/abstract/ … 03/PhysRevLett.7.118 Franken et al, 15 August 1961, Physics Review Letters.Optical modulators with 2-D layered materials www.nature.com/articles/nphoton.2016.15 Sun et al, 31 March 2016, Review Nature PhotonicsElectrical control of second-harmonic generation in a WSe2 monolayer transistor www.nature.com/articles/nnano.2015.73 Seyler et al, 20 April 2015, Letter, Nature Nanotechnology.Graphene plasmonics: A platform for Strong Light-Matter Interactions cdn-pubs.acs.org/doi/10.1021/nl201771h Koppens et al, 2011, NanoLetter, ACS Publications.Why all the fuss about 2-D semiconductors? www.nature.com/articles/nphoton.2016.53 Andres Castellanos-Gomez, 31 March 2016, Commentary, Nature Photonics.Graphene photonics and optoelectronics www.nature.com/articles/nphoton.2010.186 Bonaccorso et al, September 2010, Review, Nature Photonics.Broadband, electrically tunable third-harmonic generation in graphene www.nature.com/articles/s41565-018-0145-8 Soavi et al, 21 May 2018, Nature nanotechnology.Nonlinear optics in daily life www.osapublishing.org/oe/fullt … 1-25-30532&id=275155 Elsa Garmire 2013, OSA Publishing, Optics Express.High-harmonic generation in graphene enhanced by elliptically polarized light excitation science.sciencemag.org/content/356/6339/736 Yoshikawa et al, 19 May 2017, Science.Micromechanical resonator with dielectric nonlinearity www.nature.com/articles/s41378-018-0013-6 Mateen et al, 02 July 2018, Microsystems and Nanoengineering, Nature. Schematic for gate tuning the chemical potential: the ion-gel gating method was adopted in the study using the field-effect transistor structure with graphene (2D hexagonal lattice) supported by fused silica. The device structure measured the linear and nonlinear optical responses of graphene at room temperature and monitored the chemical potential (Ef) versus the gate voltage (Vg) in situ. Credit: Nature Photonics, doi: 10.1038/s41566-018-0175-7 , Optics Express © 2018 Phys.org , Science The birth of nonlinear optics is credited to an experiment conducted in 1961 by Peter Franken and co-workers with a pulsed ruby laser, in which they observed the nonlinear effect of second-harmonic generation (SHG, frequency doubling) for the first time. Dynamic control of optical nonlinearities remains confined to research laboratories as a spectroscopic tool at present.Now writing in Nature Photonics, Tao Jiang et al. report that nonlinear third-harmonic generation (THG, frequency tripling) can be widely tuned in graphene using an electric gate voltage. This has many potential applications—gate-tunable, nonlinear optical mechanisms of graphene and other 2-D graphene-like materials are desirable to engineer future on-chip photonic and optoelectronic applications with extremely high speed and complementary metal-oxide semiconductor (CMOS) compatibility for device fabrication. Electrically tunable second-harmonic generation was previously reported in other 2-D materials, such as Tungsten diselenide (WSe2) with excitons, although the spectral bandwidth was limited. Experimentally, tuning the input frequencies or the chemical potential (Ef) of graphene can provide detailed information about the third-order nonlinear optical response, thus far suggested in theory.Third-order nonlinear processes are also known as four-wave mixing, as they mix three fields to produce a fourth. The latest results from Jiang et al. originate from the ability to adjust the chemical potential (Ef) of graphene and electrically switch on or off single photon and multiphoton resonant transitions with ion-gel gating (also known as gate-controlled doping), for a given set of input frequencies. The experimental results matched well with theoretical calculations to provide a firm basis to comprehend third-order nonlinear optical processes in graphene and graphene-like Dirac materials. Journal information: Nature Photonics , Naturelast_img read more

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Researchers claim water irrigation efficiency efforts actually cause more water use

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. Journal information: Science New cyberattacks against urban water services possible, warn researchers Explore further More information: Grafton et al. The paradox of irrigation efficiency, Science (2018). DOI: 10.1126/science.aat9314 Citation: Researchers claim water irrigation efficiency efforts actually cause more water use (2018, August 24) retrieved 18 August 2019 from https://phys.org/news/2018-08-irrigation-efficiency-efforts.htmlcenter_img An international team of researchers has found that efforts to make irrigation systems more efficient are actually prompting more water use. In their paper published in the journal Science, the group explains the basis for their argument and offers suggestions about better ways to manage water use. © 2018 Phys.org Credit: CC0 Public Domain In recent years, it has become clear that the world is heading into a water crisis—there does not appear to be enough fresh water available to meet the coming demand. Also, natural aboveground and underground water reservoirs are being depleted with no clear alternatives in sight. In this new effort, the researchers note that one of the biggest uses of water is for growing crops—and many of those crops are grown in places that do not receive enough rainfall for proper growth. That has led to widespread irrigation. But irrigation in places like California’s Central Valley is not sustainable at its current pace—groundwater levels there have been dropping for decades. Noting that they need to take action, governments around the world have paid for research efforts aimed at finding ways to use water more efficiently—and one approach has been methods to make irrigation systems more efficient. These include technology such as drip systems, which offer plants the least amount of water possible to keep them growing.The researchers have been studying the efficiency of such systems, and have found that instead of using less water, they actually use more. They explain that this is because with normal watering systems, such as spraying fields, excess water makes its way back to surface or underground water systems. When using the more efficient methods, however, less water is able to re-enter natural systems, resulting in net losses. The researchers suggest that such efforts have thus far resulted in wasted money as many governments pay farmers to use the more efficient systems.The researchers suggest that such efforts be halted, and that more useful systems be put in place. They also note that comprehensive water measurement systems need to be used to give policymakers a tool for gauging the true results of irrigation efficiency projects.last_img read more

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Taiwan comes calling to Indian buyers

The stylish and sexy Malaika Arora Khan recently flew to the national capital for the Taiwan Excellence campaign 2012. Organised by the Bureau of Foreign Trade, Ministry of Economic Affairs – Taiwan, this campaign was implemented by the Taiwan External Trade Development Council (TAITRA), a non- profit trade promotion organisation.The bollywood star, who is also the brand ambassador of Taiwan Excellence Celebrity Endorser said, ‘It is totally like me, stylish, chic, and sexy and the products are designed for me and my family.’ Speaking about Delhi, especially the feel of the city during the ongoing festive season, she said, ‘What I like about Delhi is the food, weather, roads, the open spaces, and the spirit of festivity among the people.’ Also Read – ‘Playing Jojo was emotionally exhausting’When asked about her role as a producer for Dabang 2, she said : ‘Right now this is what I wanted to do. So I am doing it.’The actress who sizzled in the item number Munni badnam hui in the first Dabang film said of her part in the second franchisee,’ I have a small role in the movie and what is it remains to be seen.’ She further added: ‘Although I would never say I won’t act but dancing has always been my first love.’Endorsing Taiwanese products she said she uses the products herself and also for her family. The campaign  saw an increase in awareness of Taiwanese products in India by 25% this year. Also Read – Leslie doing new comedy special with NetflixSpeaking on the occasion, Wenchyi Ong, representative of Taipei Economic and Cultural Center (TECC), India, government of R.O.C.( Taiwan) said,’We are late in arriving in the Indian market, which has a great long-term potential, but nevertheless we are enthusiastic about Taiwanese products for the emerging market in India.’This year about 32 associate brand companies, joined the Taiwan Excellence Campaign.Taiwan External Trade Development Council (TAITRA), a non-profit trade promotion organisation, is soon bringing Taiwan’s products at the Select City Walk Mall. So check out some Taiwanese products as they will be showcased from the 1 to 5 November. read more

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Evolved minds and art

first_imgPainter Tanish Karmakar’s exhibition To Yearn of an Evolved Mind was on display at AIFACS in the Capital. Showcased from 30 July to 5 August, the exhibition got some glowing reviews from art lovers and critics. A 16 year old, student of class 11, Karmakar played with his observation on human interpretation in his works.  A simple boy of few words, Karmakar has deep insight into his world of dreams.  According to him, ‘If science evolves our life, art should evolve our mind. But again, besides being thought provoking, art also needs to be relaxing, something to energize us while we take on the challenges of life. My paintings are not just mere illustrations to adorn your walls, they, I sincerely hope, are the catalysts to evolve your psyche. This, is my purpose for art.’ Also Read – ‘Playing Jojo was emotionally exhausting’The exhibition was inaugurated by the eminent artist KR Subbana, Vice Chairman, Lalit Kala Akademy. Furthermore, the event was  blessed by the presence of Art Legend Padamshree awardee Ram Sutar. The boy was blessed and encouraged by many well known personalities. Karmakar’s art journey began with his participation in a painting competition at the age of three where he won the first prize. Since then, numerous prizes have followed including ones from the Ministry of Defense and the Ministry of Environment and Forests just to name a few. While attending workshops at NGMA, Bal Bharti his works got widely appreciated. Though he is just a 12th grader, Karmakar wants to give art and its purpose a whole new meaning.last_img read more

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Indiaheavy US firm Cognizants OctDec net rises 12

first_imgIT services major Cognizant on Wednesday said its net profit rose 12 per cent to $362.89 million for the quarter ended December 31, helped by increased traction from consulting, digital and business segments.It had posted net profit of $324.33 million in the year-ago period, the US-based firm said in a statement. A large part of the company’s workforce is based in India. Revenues rose by 16 per cent to $2.74 billion in the October-December quarter of 2014, as against $2.36 billion in the year-ago period. Also Read – I-T issues 17-point checklist to trace unaccounted DeMO cashThe company follows January-December as its fiscal year. Cognizant expects revenues in January-March quarter of 2015 to be at least $2.88 billion. For the entire year, it expects revenues to rise to at least $12.21 billion.The firm expects currency exchange rates to negatively impact its revenues in 2015 by about 2 per cent. Cognizant CEO Francisco D’Souza said, “Despite unfavourable European currency movements during fourth quarter, we finished 2014 with strong revenue performance and believe we are well positioned to continue that momentum into 2015 on strength of integrated consulting, technology, digital and business services capabilities.” Also Read – Lanka launches ambitious tourism programme to woo Indian touristsThe firm added (net) about 11,800 employees, including TriZetto and the year-end headcount was around 211,500. Cognizant President Gordon Coburn said, “Integration of our $2.8 billion acquisition of TriZetto, completed in the fourth quarter, is well underway and we’re excited by the healthcare opportunities we see.” In September last year, Cognizant said it will acquire US-based TriZetto for $2.7 billion in an all cash deal, a move which will help the IT services firm tap the lucrative healthcare IT software and solutions market. “As we crossed 200,000 employee mark, we’ve been able to recruit top talent from around the world and believe we are in a unique position in the market to address a wide range of opportunities fuelled by digital transformations across all of our industry segments, service lines and geographies,” he added. On the outlook, the firm said: “In the first quarter 2015 revenue are expected to be at least $2.88 billion. Full year 2015 revenue are expected to be at least $12.21 billion, up at least 19 per cent compared to 2014.” For the entire 2014, net profit rose by 17 per cent to $1.44 billion compared to $1.23 billion in 2013.last_img read more

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Govt to install reflectors on road dividers to reduce accidents

first_imgKolkata: The state government will install reflectors on road dividers to prevent accidents at night, under the Safe Drive Save Life programme.The step has been taken after it was found that the incidents of drivers hitting the road dividers have gone up both on the city roads and on highways in recent times.The work to install reflectors between Gol Park and Dhakuria has already started. Senior police officers said during night, particularly when it rains heavily, drivers often fail to spot the dividers and hit them. In areas where there are small road dividers, drivers mount them after failing to negotiate lanes. Also Read – Rain batters Kolkata, cripples normal lifeThe reflectors will be seen from more than 50 feet away, even during rainy nights. The officers said because of intense vigil at night and installation of guard walls, the number of road accidents at night has gone down considerably. They hope that the installation of reflectors will be of great help to the drivers.Police all over the state will distribute Safe Drive Save Life stickers free of cost to the drivers to install them on the steering. Chief Minister Mamata Banerjee took the decision after a police car met with a road accident. The police officers said the sticker on the steering will work as a caution to the drivers.The state Transport department has left no stones unturned to reduce the number of road accidents and train drivers to pick up proper driving skills.last_img read more

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Fashion fiesta

first_imgFDCI presented the Amazon India Fashion Week in association with Maybelline Autumn Winter ‘16 at Jawaharlal Nehru Stadium in the national Capital from March 16 to March 20. The opening show of Varun Bahl on Wednesday set the tone for the fashion fiesta.Being one of the most important events in the country’s fashion calendar- Amazon India fashion Week provided a platform to almost hundred designers. There is more to fashion than just what the movie stars wear. Fashion includes clothes, jewellery, accessories like shoes, bags and belts, hairstyles, makeup and most importantly passion. Also Read – ‘Playing Jojo was emotionally exhausting’Friday afternoon saw some exquisite jewellery collection from Sahai Amber Pariddi, Nitya and Vasundhara. Sahai Amber Pariddi displayed their new collection ‘Memoir’, which was inspired by the captivating and mysterious oceans and tried to portray that the sea is the perfect summation of the modern day woman who is strong and dreams big. The elegant accessory pieces had their silhouettes derived from the fluid merging and layering of the different hues of the crashing waves and vibrancy of the eco systems thriving underwater.  Also Read – Leslie doing new comedy special with NetflixThe show stopper of Mine of Design was none other than Sayani Gupta who donned some beautiful pieces of jewellery and walked the ramp with confidence, “I am very comfortable wearing the jewellery, since I don’t realise the weight, even though I’ve a lot of pieces on. I love aquamarine, turquoise and pearls and I can actually wear them (the jewellery pieces) with just a blue jeans and white shirt,” said the actor happily.Nitya’s jewellery collection was called ‘Modern Mughals’, for the young women excelling in their fields. “We have used a lot of acidic bright colours and jewel stones, on gold plated brass. We are so rooted to our culture that I don’t think we’ll ever stop wearing jewellery,” smiled Nitya when asked whether today’s women would like to wear heavy jewellery. Vasundhara Mantri’s collection called ‘Werifesteria’ was all about natural elements of the forest. The collection also had some beautiful shoes with ornamental dragonflies or bugs on them. The display was like a walk in the wilderness with incorporated natural rocks, filigree leaves, twigs, branches, and metal insects, bugs and butterflies in different forms and patterns. Actor Aditi Rao Hydari was the showstopper for designer Shruti Sancheti who showcased her collection titled ‘Constantinople’. “It was seamlessly organised and I loved the fact that Shruti was inspired by Istanbul,” said Aditi Rao Hydari. “The shoes are exquisite and specially made for this collection while the dress can be worn almost anywhere…” added the actor flaunting her beloved attire.The collection ‘Constantinople’ featured ultra luxurious modern cuts with conflicting pattern clashes of fluid paisley, geometric mosaics and rustic clamp dying, forming the core of this line. It was a paradox of conflicting crafts, fabrics and cultural ethos, deeply influenced by the unconventional characteristics of the historic and exotic city. The collection offers natural fibres like finely woven Karnataka silk, chanderi, chambray, wool, teamed with international favourites like felt and denim, to impart a global appeal.Chandrani Siingh Fllora displayed her latest collection ‘Mrityunjay’, a culmination of her personal journey during this time. Symbols of Shiva like the trishul and conch shell were incorporated in the prints and embroidery of the pieces. The collection was dominated by dark blue, bottle green and various shades of yellow as she used hand-woven fabric and experimented with stripes and ombre.Providing an exquisite array of designs rooted in elegance, long, fluid fabrics which are fashioned into pieces of timeless antiquity perfect for women of all cultures and eras were showcased by Sulakshana Monga in her collection ‘Pathless woods’. Reynu Tandon’s collection was a classic combination of fit and unfit, as she defined her USP as her flamboyant perspective of colors, contour and soft intricacy. For the collection, Reynu had handpicked unique items, since it is not easy to re-invent styles that last for decades and the audience got to see a potpourri of versatility through that. She has infused her thread work that connects all the pieces together. The unique silhouettes with balloon puff opulent sleeves were re-introduced in fashion and were combined with classic capes and chic vintage heritage jackets.last_img read more

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State keen to come up with green towns not just buildings

first_imgKolkata: The Bengal government is planning to develop energy efficient towns where buildings would be constructed following certain parameters imposed by the state government thereby reducing the overall consumption of electricity.This comes at a time when the Centre is trying to introduce Energy Conservation Building Code (ECBC) for constructing residential buildings in all the states where the real estate developers will have to keep in mind certain parameters while setting up both commercial and residential buildings. Also Read – Rain batters Kolkata, cripples normal lifeThe Mamata Banerjee government may not implement the ECBC code as proposed by the Centre because it is only meant for the buildings whereas the Bengal government is giving emphasis on the development of an entire green town. It may modify the code to suit the regional needs.It may be mentioned here that the Centre is in the process of preparing ECBC for residential buildings. In case of commercial buildings, the Union Power ministry had already framed certain rules on how the buildings would be constructed keeping in mind the environmental issues. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedState Power minister Sobhandeb Chattopadhyay said instead of constructing a particular energy efficient building, the state government is focusing on the development of an entire town in such a manner so that consumption of electricity is minimal.”Chief Minister Mamata Banerjee is keener on developing towns in such a manner so that they are more energy efficient. The Centre is bringing a new policy where a building will be constructed on the basis of certain parameters. But our government is working on the prospect of creating greener cities. Constructing a particular building by following energy efficient building code will hardly contribute to make a city green. Our Chief Minister is interested in developing an entire green city in the true sense of the term,” Chattopadhyay said. The Bengal government has already undertaken a two pronged approach to cater to the energy demands of its citizens and also ensured the emission of harmful gasses is low in the state. The Mamata Banerjee government is promoting greater use of renewable energy in the state mainly through solar use. Efforts are being made by the state Power department to efficiently use the renewable energy through various innovative policies.”Our government will work towards the development of energy efficient towns instead of constructing a building by implementing the ECBC. A town will be constructed in such a manner where the buildings will not only be eco friendly but other environmental aspects will be kept in mind,” Chattopadhyay said.It was learnt that many other states are yet to decide whether they would implement the ECBC code framed by the Centre while allowing the construction of residential buildings.last_img read more

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Inland Waterways Authority of India forays into PPP

first_imgKolkata: Inland Waterways Authority of India (IWAI) will make its foray into Public Private Partnership (PPP) on Tuesday when it hands over the operation and management of its terminals in Kolkata to M/s Summit Alliance Port East Gateway (India) Pvt Limited (SAPEL) on a supply, operate and maintain (SOM) model. The handing over will be done in the presence of Union Shipping Secretary Gopal Krishna at an event in Kolkata. The terminals GR Jetty-I & BISN and GR Jetty-II of Inland Water Transport (IWT) will be handed over to SAPEL for equipping, operating and managing on a revenue sharing model. The operator will have the right to collect user fees from the users as per the tariff rates notified by IWAI. Also Read – Rain batters Kolkata, cripples normal lifeAccording to IWAI Chairman Pravir Pandey, under the transactional structure worked out by International Finance Corporation (IFC), the operator will undertake the operations and maintenance services at both Kolkata and Patna clusters and invest in cargo handling equipment, container handling equipment and warehousing. The operator will also provide labour, professionals, supervisory and managerial personnel for performance of operations and maintenance services. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedThe proposed project will facilitate a modal shift of up to 55 percent of the potential cargo in the catchment area to IWT mode. The existing potential of anchor cargo is of 56,000 TEUs (to/from catchment area) during the base year and expected to grow upto 2,50,000 TEUs over the next 15 years. The current handling capacity of terminal is 1.6 MT which includes bulk and break — bulk cargo. The contract will be valid for a period of 30 years. M/s SAPEL was awarded the contract in August, 2017 under a revenue sharing arrangement of 61.70 percent to itself and 38.30 percent to IWAI through a global tendering process for this work at Garden Reach Terminal in Kolkata and Gaighat and Kalughat Terminal in Patna. The transportation of trucks on vessels from BISN jetty to Sankrail on the bank and participation of private sector in operation and management of the facilities will improve the operational efficiency of the jetties. The Kolkata terminals will also facilitate domestic bound and EXIM cargo for North Eastern Region and Bangladesh even as it will prove advantageous for shippers plying on the Indo-Bangladesh Protocol Route.last_img read more

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SAILs endeavour to empower india

first_imgThe Indian steel industry believes that there is a need for levying anti-dumping duties on cheap and low quality steel and stainless steel imports, and the government is supporting and safeguarding the domestic industry by introducing duties, which were showcased at the India International Trade Fair, 2016 (IITF).ESSAR Steel and Jindal Stainless Management Services were the part of the Ministry of Steel Pavilion at the 36th edition of India International Trade Fair, 2016 (IITF). The other steel companies which are a part of the pavilion are Ferro Scrap Nigam Limited (FSNL), Hindustan Steelworks Construction Limited (HSCL), Joint Plant Committee (JPC), JSW Steel,   Metal Scrap Trade Corporation Ltd (MSTC), National Mineral Development Corporation (NMDC), Rashtriya Ispat Nigam Limited (RINL), Steel Authority of India Ltd (SAIL) and TATA Steel. Also Read – Add new books to your shelfThe government has supported them and introduced several duties with which it is trying to safeguard the domestic industry. Pricing is one and quality is another aspect of anti-dumping. Supporting the government’s move to curb cheap imports from countries like China and Australia, Steel Authority’s anti-dumping duty is already there on steel and stainless steel. In this way, the government is helping the industry and domestic market.Another great initiative by the ministry of steel was coming up with the idea of a single pavilion for leading public and private steel companies of India. It not only brings the entire industry on a single platform but also helps in saving cost. Steel Authority very artfully showcased how this versatile alloy has become an important part of our society. Everybody is using steel in one way or the other, like in a city, everything from buildings to airports and from metro to roadways, incorporates steel in some manner. As the steel industry is fond of saying, steel is everywhere in our lives.  Also Read – Over 2 hours screen time daily will make your kids impulsiveThe Indian Steel Industry is continuing to buck the global trend of slowdown in steel production by maintaining the growth momentum. The government of India has taken decisions to provide an enabling environment for growth of Indian steel industry, and the government is keeping a constant vigil on external and internal growth drivers, constraints and changes in dynamic world steel market.  With renewed emphasis on infrastructure development and other related sectors, steel is likely to be in demand in the coming years for meeting the requirements of a vibrant and strong Indian economy.last_img read more

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Ensure history is not changed CM

first_imgKolkata: Chief Minister Mamata Banerjee on Monday urged students and researchers to preserve history so that it is not changed due to different political ideologies.”I request students and researchers to make efforts to conserve our history and make sure it is not changed due to any political ideology,” Banerjee said during her address at the Convocation ceremony of Calcutta University here. Indirectly alluding to an atmosphere of divisiveness, she wished that the Lord must throw more light all around so that there is “no narrow-mindedness and all differences between people can be erased”. Also Read – Rain batters Kolkata, cripples normal lifeIt may be mentioned that Banerjee, in recent times, has been very vocal against the BJP accusing them of changing the names of historical places and institutions unilaterally to suit their own political vested interest. She maintained that Calcutta University’s credit lies in imparting education to the common and the poor. “CU is a place of the commoner, by the commoner and for the commoner and you should continue to function in the same pattern,” she added. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedShe hailed Calcutta University for making no demarcation between elite class and middle-class students and said the varsity maintains its old values which are golden ones. “I come here because I feel at home,” she maintained. Banerjee took a dig at Presidency University and Jadavpur University accusing them of narrow mindedness when it comes to extending an invitation to people. “At Calcutta University, you invite everybody at the Convocation — the teachers, students and even the non-teaching staff but I am saddened at the fact that one or two big universities do not do so. When I heard that Presidency University had decided to hold its Convocation at Raj Bhavan, I was so shocked. A student at Jadavpur University had refused to accept Convocation certificate from the Governor. Politics should not come in the way when it comes to honouring people,” she said. The Chief Minister was referring to Presidency University holding its Convocation outside the campus in September in the wake of students’ movement regarding the delay in handover of Hindu Hostel. The Convocation was scheduled to be held at Raj Bhavan, though the venue was changed to Nandan IV at the last moment. No students were invited to attend the programme and the degrees were later handed over to them inside the university. Governor Keshari Nath Tripathi who is the Chancellor of both Jadavpur and Presidency University was seated on the dais when the Chief Minister spoke. Former Bengal Governor Gopal Krishna Gandhi who was conferred D.Litt at the Convocation said freedom of speech and expression should be exercised fearlessly in the country. “Fear is a great evil and is completely inconsistent with democracy and republicanism,” he said. He urged the Chief Minister to play a leading role in upholding the liberty and republicanism of the country. “You have a great role and responsibility to play in keeping the torch of liberty and republicanism alive and may this state be the torch bearer of those great ideals of India’s freedom,” Gandhi added. The recipients of DSC were Dr. Dilip Mahalanobis and Dr. Sukumar Mukherjee while Manoj Pant, Principal Secretary of state Public Health Engineering Department and Land Reforms Commissioner was awarded Ph.D degree at the Convocation.last_img read more

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Women to manage 115 polling stations in North Kolkata

first_imgKolkata: As many as 115 polling stations out of a total of 1,862 in the North Kolkata Parliamentary Constituency, will be managed by women.During a media interaction on Monday, Dibyendu Sarkar, DEO North Kolkata, said that 115 polling stations will be fully run by women poll personnel in the seventh phase of elections scheduled to take place on May 19. There are around 14.76 lakh voters in North Kolkata, out of which 6.47 lakh are women. “There are around 506 locations under the Lok Sabha constituency in North Kolkata, out of which 33 locations will be managed by women. Altogether, there will be as many as 612 polling personnel in 153 polling stations,” Sarkar said. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataThe officials of the Election Commission are conducting camps to make the polling personnel aware about the overall functioning of Electronic Voting Machine (EVM) and Voter verifiable paper audit trail (VVPAT). Various facilities, as specified by the Election Commission of India (ECI), will be put in place in all the polling stations under this constituency. Adequate security deployments will also be made to ensure free and fair elections at each booth. Also Read – Lightning kills 8, injures 16 in stateA newly built training hall with a huge capacity has been thrown open at the DEO’s office in North Kolkata, where various training related programmes would be conducted from time to time. All the polling personnel will be made aware on how to conduct the poll process. The office of the DEO has come up with various innovative initiatives to reach out to the people. The summary revision of the electoral rolls of 2019 has also been initiated to reach out to the voters. Voters are also being encouraged to take part in the demonstration on how to cast their votes in the EVMs and see paper trail in the VVPATs.last_img read more

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Fastacting nasal spray can help treat depression

first_imgAn antidepressant nasal-spray can be a safe and effective way to treat depression in patients who do not respond to existing treatments, a study has found. Being common and treatment resistant, individuals with depression are often unable to relieve their symptoms despite trying anti-depressants, researchers said. According to the study published in the American Journal of Psychiatry, esketamine nasal spray, in conjunction with an oral antidepressant, offers a new fast-acting treatment for people that have not responded to other depression treatments. Also Read – Add new books to your shelf”Not only was adjunctive esketamine therapy effective, the improvement was evident within the first 24 hours,” said Michael Thase from the University of Pennsylvania in the US. “The novel mechanism of action of esketamine, coupled with the rapidity of benefit, underpin just how important this development is for patients with difficult to treat depression,” said Thase. The study was conducted on nearly 200 adults with moderate to severe depression and a history of not responding to at least two antidepressants. Also Read – Over 2 hours screen time daily will make your kids impulsiveParticipants were randomly assigned to one of two groups. One group was switched from their current treatment to esketamine nasal spray – 56 or 84 milligrammes twice weekly – plus a newly initiated antidepressant (duloxetine, escitalopram, sertraline, or extended-release venlafaxine). The other group was switched from their current treatment to a placebo nasal spray in combination with a new antidepressant. The improvement in depression among those in the esketamine group was significantly greater than the placebo group at day 28. Similar improvements were seen at earlier points in time. The therapy was effective and the improvement was evident within the first 24 hours, said Thase. Researchers also pointed out that the esketamine group experienced common side effects like dissociation, nausea, vertigo, dysgeusia (distortion of the sense of taste) and dizziness which, however, resolved after 1.5 hours.last_img read more

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People of the Stone Age Enjoyed a Dinner of Caviar

first_imgMany centuries before caviar became a prized — and pricey — delicacy served at restaurants, something amazingly similar was eaten by Stone Age humans out of their clay pots. That’s what a new study that was published in late 2018 in the journal PLOS One has concluded. The study featured protein analysis of a 6,000-year-old cooking pot, revealing traces of cooked fish roe. The pot was recovered from an archaeological site in Germany.Fragment of Endmesolithic pottery. Photo by 2018 Shevchenko et al. CC BY SA 4.0“For the study, researchers from Germany conducted a protein analysis of charred food remains caked to the shards of an Stone Age clay cooking vessel,” reported Mental Floss. “After isolating roughly 300 proteins and comparing them to that of boiled fresh fish roe and tissue, they were able to the identify the food scraps as carp roe, or eggs.”Prehistoric societies knew how to make full use of natural resources, the study authors pointed out.These groups of humans often lived close to rivers or lake shores. The scientists’ best guess is that these were hunter-gatherers who camped near lakes.Stone Age by Viktor VasnetsovTrying to understand how the Stone Age people used “aquatic resources,” the scientists assembled  “zooarchaeological” materials (shellfish, bones, scales), processing tools, and related art objects like zoomorphic figurines, paintings, and adornments. They also analyzed the DNA recovered from ancient fishbones.According to Smithsonian, the lead author, Anna Shevchenko of the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany, “identified the elements of this prehistoric recipe by conducting protein analysis of charred food traces left on a clay cooking vessel dated to around 4000 B.C.”Common carpProteins on the clay that they analyzed matched those of the common carp (Cyprinus carpio).Specifically, the proteins are common in the fish eggs. Other proteins they looked at suggest that the pot also held fish flesh. The authors say that the long-ago diners may have prepared their delicacy by poaching roe in fish broth or water, using leaves to cover the pot, according to Nature.Fragment of ancient clay cooking pot. Photo by 2018 Shevchenko et al. CC BY SA 4.0The clay shards that they analyzed were recovered from Friesack 4 in Brandenburg, Germany, which is a Stone Age archaeological site that has yielded about 150,000 artifacts for study, including objects made from antlers, wood, and bone, since the date it was discovered in the 1930s.In the same study, the researchers report that they also found remnants of bone-in pork on a vessel recovered from the site.Through such research, scientists have confirmed that some of the foods we think of as modern delicacies have been around for thousands of years, not only fish eggs but also cheese, salad dressing, and bone broth.Electron microscopy of rim and basal foodcrusts from #3258 vessel. Photo by 2018 Shevchenko et al. CC BY SA 4.0This research technique falls under the burgeoning field of proteomics, or the large-scale study of protein sets, according to Smithsonian. Proteomics allows researchers to focus on species- or age-specific proteins, providing a higher level of detail than most archaeological assessments of historical food substances.The scientists said in a statement: “Burnt food particles are often found adhering to vessel shards on archaeological excavations. The analysis of their protein content helps us understand many aspects of prehistoric life.”To analyze a ceramic bowl of burnt food leftovers found at an archaeological site in the state of Brandenburg in Germany, scientists from the Brandenburg State Office for Historic Preservation and the Archaeological Museum (BLDAM) contacted the mass spectrometry experts at the Max Planck Institute for Molecular Cell Biology and Genetics (MPI-CBG) in Dresden.Read another story from us: Unearthing Fast Food Joints and Takeaway Culture in Ancient Rome“The team led by Anna Shevchenko at the MPI-CBG developed a new proteomics analysis that can identify more than 300 proteins and differentiate ancient and contemporary proteins. In this way, the researchers found in the charred remains of prehistoric food the fish roe of a carp,” according to the statement.last_img read more

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