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. © 2016 Phys.org Calculated electron density (green) and magnetic field strength (yellow-orange-blue) inside a structured plastic target 300 femtoseconds after being irradiated with an intense laser pulse from the left-hand side. The red dots indicate locations where photons with energy greater than 10 MeV were emitted in this simulation. The photons (not shown) exit to the right. Credit: A. V. Arefiev, D. J. Stark, T. Toncian/Univ. of Texas, via Physics Explore further Journal information: Physical Review Letters Plasma research shows promise for future compact accelerators
The soft actuator maintained a flat and unwrinkled form under ambient conditions with relative humidity, while bending in response to increasing/decreasing humidity in the environment, which Cai et al. quantitatively analyzed. They noted excellent actuator performance and controllable bending angles in a variety of humidity levels. The scientists next investigated the electrical actuation of the device by connecting an MXene-cellulose strip to two copper wires. The bending angle almost linearly decreased with increasing electrical power, while the soft actuator only required a low voltage to achieve extreme actuation. Compared to humidity-based actuation, the scientists achieved larger bending angles with electrothermal actuation. The scientists also recorded temperature variation and binding angles of soft actuators using near infrared (NIR) light irradiation. They observed remarkable synergistic actuation motion of the MXene/cellulose composite material, in contrast to poor actuation performance of the individual components. Based on the observed optical absorption, photothermal conversion and electrochemical actuation, Cai et al anticipate the use of these composite smart soft actuators in photo-responsive functions. Cai et al. further investigated the photoinduced mechanical forces of the material under NIR light irradiation on a mechanical analyzer. The actuation process of MXCC/PC was rapid and reversible. The scientists studied the structural changes of the MXCC/PC and MXene/PC actuators under different intensities of illumination using X-ray diffraction (XRD) measurements to show amorphous character of cellulose and PC membrane. They investigated the mechanical behavior using finite element modelling methods (FEM) to further understand the actuation process of the composite material. The modeling results agreed with the experimental outcomes in the study. To demonstrate programmable actuation behavior, the scientists developed a series of sophisticated configurations. Including a double folding U-shaped actuator, trefoil arch-shaped actuator and self-blooming flower where the petals opened and bloomed before NIR irradiation to close rapidly on exposure to NIR. Additionally, the scientists explored a variety of smart devices such as worm-like robots, smart switches, an encryption device as well as IR dynamic display and camouflage to extend the primary concept. Furthermore, Cai et al. constructed a smart switch by patterning cross-shaped MXCC on the PC membrane, which they controlled using wireless NIR light. Based on the principles, the scientists also formed an open electrical circuit to switch on/off a smart watch using NIR light. For data encryption, based on the programmable MXene-cellulose ink, Cai et al. engineered a desired pattern and conveyed the information by local heating using NIR light or electricity. The information was only readable using IR and invisible to the human eye, providing better suited information encryption beyond machine readable barcodes and QR codes. The ability to integrate diverse functionalities into one system to achieve camouflage, display and actuation is important and useful in multiple disciplines. These devices confirmed the possibility of using MXCC/PC membranes to serve multiple functions in smart soft systems including information encryption, camouflage and thermo-responsive behavior. , Science © 2019 Science X Network Explore further Journal information: Science Advances Citation: Bioinspired MXene-based actuators for programmable smart devices (2019, July 18) retrieved 18 August 2019 from https://phys.org/news/2019-07-bioinspired-mxene-based-actuators-programmable-smart.html A variety of environmental stimuli such as humidity, temperature, electricity, light and pH can trigger physical alterations of these materials. But it is presently difficult to enhance the speed of actuation and scale-up shape changes due to poor mechanical and thermal instability that restrict their capabilities. Building a smart actuator that responds to diverse stimuli such as humidity, electricity, heat or light with fast actuation, large-shape deformation, programmable adaptability and robust stability is therefore highly desirable. To build new and improved material properties, the materials scientists must therefore explore previously unidentified combinatorial materials and rationally design device configurations to invent high-performance actuators. The elaborate structure, components, and actuation mechanism of the MXene-cellulose–based actuator. (A) Photograph of a natural leaf. (B) Schematic diagram of a leaf structure. (C) Schematic diagram of the MXCC/PC bilayer-structured actuator, which is composed of MXCC and a PC filter membrane. (D) Actuation mechanism of the MXCC/PC bilayer-structured actuator. Macroscopic and microcosmic (involving H bonds) structure changes of the MXCC/PC bilayer-structured actuator in response to hygroscopic and thermal stimuli simultaneously (both hygroscopic and thermal actuation processes are controlled by electrical and NIR light actuation). Scanning electron microscopy images of the MXCC (E) and the PC filter membrane (F). Contact angle measurement of the MXCC (G) and PC filter membrane (H). (I) Transmission electron microscopy image of the 2D MXene nanosheet (inset: SAED pattern). Credit: Science Advances, doi: 10.1126/sciadv.aaw7956 During photosynthesis, natural leaves with elaborate architectures and functional components can harvest and convert solar energy into chemical fuels that are converted into energy. The biological energy production has provided materials scientists a new bioinspired paradigm to produce many autonomous systems, including light-triggered motion. In a recent report, Guofo Cai and co-workers at the departments of Materials Science and Engineering, Astronautic Science and Mechanics, and Chemical Engineering, developed an unprecedented bilayered actuator base on MXene (Ti3C2Tx)-cellulose composites (MXCC) and polycarbonate (PC) membranes. Programmable soft actuators show the great potential of soft robotics , Advanced Materials Representative programmable motions for the MXCC/PC bilayer-structured actuator. (A) Double folding U-shape actuator. (B) Trefoil arch–shaped actuator. (C) Self-folding box. (D) Self-blooming flower. Green dashed lines in (C) and (D) (left diagram drawing) are the slight creases created on the bottom of the box and flower to make the self-folding box and self-blooming flower work well under NIR irradiation. (Photo credit: Guofa Cai, Nanyang Technological University.) Credit: Science Advances, doi: 10.1126/sciadv.aaw7956 A real-time digital camera video of the MXCC/PC bilayer-structured actuator upon sequential on/off NIR light irradiation. Credit: Science Advances, doi: 10.1126/sciadv.aaw7956 More information: Guofa Cai et al. Leaf-inspired multiresponsive MXene-based actuator for programmable smart devices, Science Advances (2019). DOI: 10.1126/sciadv.aaw7956 M. Ma et al. Bio-Inspired Polymer Composite Actuator and Generator Driven by Water Gradients, Science (2013). DOI: 10.1126/science.1230262 Xili Lu et al. Liquid-Crystalline Dynamic Networks Doped with Gold Nanorods Showing Enhanced Photocontrol of Actuation, Advanced Materials (2018). DOI: 10.1002/adma.201706597 R. H. Baughman. MATERIALS SCIENCE: Playing Nature’s Game with Artificial Muscles, Science (2005). DOI: 10.1126/science.1099010 The new composite materials, rational design and low-cost fabrication introduced in the study, alongside synthetic strategies implemented by the scientists, will make the MXCC/PC membrane systems accessible for broad scientific and engineering fields. In this way, Guofa Cai and co-workers developed and established a new class of multiresponsive materials and devices with unprecedented integration of multiple properties inspired by multifunctional biological structures. The MXCC/PC membrane systems mimicked crucial features of a natural leaf from the microstructure to photosynthetic capabilities, which included energy-harvesting and conversion. The bilayer actuators showed strong features, similar to state-of-the-art multiresponsive actuators. The explored materials and advanced systems can be further developed to establish novel possibilities for revolutionary technologies in the fields of soft robotics, information encryption and IR dynamic display. LEFT: Mechanical performance and motions of the MXCC/PC bilayer-structured actuator caused by NIR light. (A) Typical static force and strain changes of the MXCC- and cellulose-based actuators during one actuation cycle when NIR light illumination was turned on and off (50 mW cm−2). (B) Plot of the static force and strain of the MXCC- and cellulose-based actuators as a function of time for five consecutive NIR light on and off cycles, indicating the reversible, stable, and rapid actuation process. (C) Static force changes of the MXCC-based actuator under different NIR illumination intensities (from 5 to 200 mW cm−2). (D) Bending angle of the MXCC-based actuator under different NIR illumination intensities (from 5 to 200 mW cm−2). RIGHT: Structure change under different NIR illumination intensities and mechanical modeling. (A) XRD patterns of MXCC- and MXene-based actuators under different NIR light illumination intensities (solid lines, MXCC-based actuator; dashed lines, MXene-based actuator). (B) Corresponding d-spacing of the MXCC- and MXene-based actuators under different NIR light illumination intensities. (C) Simulated and experimental results of the MXCC-based actuator. (D) Simulated results of the MXCC-based actuator under NIR light illumination. Credit: Science Advances, doi: 10.1126/sciadv.aaw7956 A real-time digital camera video of smart switch upon sequential on/off NIR light irradiation. Credit: Science Advances, doi: 10.1126/sciadv.aaw7956 MXene (Ti3C2Tx) used in the present work belongs to a new family of liquid-crystalline, two-dimensional (2-D) metal carbides with excellent electrical conductivity, thermal conductivity and photothermal conversion to form multiresponsive and potentially high performance actuators. Only a single example currently exists of the use of MXene as an electrochemical actuator. In the present work, therefore, Cai et al. aimed at using MXene as a multiresponsive soft actuator to explore leaf-inspired, sophisticated architecture for simple actuation, coupled with synergistic functional components. Inspired by the biological architecture and photosynthetic mechanism of a natural leaf, Cai et al. designed an asymmetric, bilayered soft actuator using single-crystal, 2-D MXene nanosheets to harvest electric or light energy for conversion into thermal energy. For this, they used biocompatible, cellulose nanofibers to form the vein skeleton for rapid leaf-like shape changes alongside polycarbonate (PC) filter membranes to form the stomata and epidermis for water insertion and extraction to or from the MXene-cellulose composites (MXCC). The scientists confirmed the increased absorption of water in MXCC due to the presence of cellulose using Fourier Transform Infrared (FTIR) spectra. Using selected area electron diffraction (SAED) patterns, they detected the presence of MXene as a hexagonal structure and single crystallinity without defects at the nanometer scale. The device mimicked the sophisticated architecture of a leaf and showed energy-harvesting and conversion capabilities similar to photosynthesis. The bilayered actuator contained highly desirable features including; multi-responsiveness, low-power actuation, fast actuation speed, large-shape deformation, robust stability and programmable adaptability—well suited for modern soft actuator-based smart systems. Cai et al. believe these adaptive soft systems will be attractive as revolutionary technologies to build soft robots, smart switches, for information encryption, infrared dynamic display, camouflage and temperature regulation. They envision additional uses of the technology to develop human-machine interfaces such as haptics. The study is now published in Science Advances. Materials scientists have studied materials and devices that dynamically change shape, size and electrical/mechanical properties in response to external stimuli for a variety of applications. Such devices have important functions as actuators, artificial muscles, in robotics, as energy generators, sensors and smart curtains. Scientists have devoted substantial efforts to develop smart actuators based on a variety of active materials such as carbon nanotubes and graphene, shape memory polymers, gels, conjugated polymers and liquid crystal elastomers as well as ceramics and alloys. 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.
“It is a pro-corporate budget,” Congress President Sonia Gandhi said when asked about her reaction on it.Slamming the budget as one that promises nothing new, party leaders said the plan to bring a new law on blackmoney meant that the government was not bringing illegal money stashed abroad on which it had made tall promises.”Finance Minister Arun Jaitely is a good lawyer. But he presented the government’s case on Saturday as a very bad lawyer,” remarked Leader of Congress in Lok Sabha Mallikarjun Kharge. Also Read – Need to understand why law graduate’s natural choice is not legal profession: CJIHe charged that the budget was a “repayment by the BJP government to the rich and corporates who had supported them during Lok Sabha polls”.Former Rural Development Minister Jairam Ramesh said the budget was a “dhanwapsi” programme. “You (BJP) had taken in elections. You are paying back,” he charged.The allusion was to the controversial “gharwapasi” programme by saffron parties.Ramesh also said the “budget has (SIMI) in it…Skill India, Make India.” Also Read – Health remains key challenge in India’s development: KovindThe Congress President’s political secretary Ahmed Patel said, “The hype over the budget had created lot of hope but the outcome is disappointing”.”Allocation for Sarvashiksha Abhiyan is cut. Farmers get nothing. Service tax increase hurts the poor and the rich will pay less tax,” Patel said. Holding that the budget lacked any substantial investment in the social sector, Kharge charged that it was “pro-industrialist”, “pro-corporate” and not meant for the poor. “The government got a lot of money because of the fall of prices in crude oil. But you did not use it for the poor for inclusive development. The budget was also made keeping in mind the future state elections in Bihar and West Bengal in mind,” he said.”The budget fills the coffers of the rich and empties that of the poor. It has not launched any new programme and repackaged old schemes with cosmetic changes.”The budget does not give an answer sheet. He has only given a question paper,” Kharge said, adding that Jaitley’s promise for special packages for states raises doubts as they have been announced for states where elections are due.Former Parliamentary Affairs Kamal Nath said the budget does not bring the stimulus that should have come in the country’s economy.”The budget is a great disappointment. It does nothing that stimulates the rural economy or growth or generate employment. It’s a budget that promises setting up committee, commissions.”This is a hollow budget, a budget of event management. There is nothing in this budget which will increase the purchase capacity of the youth. Corporate tax has been reduced, which will only benefit the rich,” he said, adding he will not give more than 2 or 3 out of 10 to Jaitley if the budget is rated like this.All India Congress Committee General Secretary Janardan Dwivedi said the budget is “very ordinary”.”The budget is not special from any point of view. Government talks a lot about poor but nothing has been done in the budget about the poor.Common man will have to pay for service tax and other similar proposals of the government.”Former Union Minister Jyotiraditya Scindia termed the budget as “plain and hollow”.
Kolkata: Three BJP workers were arrested from Gopiballavpur in Jhargram on Sunday on charges of attempting to distribute cash a day ahead of the Panchayat polls. Police claimed that they have found leaflets of the BJP from the arrested persons. Chief Minister Mamata Banerjee has also raised the allegation of distribution of cash and urged people to be alert and to inform the police in case they find anyone distributing money. Police said they were patrolling the area when they received information that some have gathered to distribute cash among people. The police went to the spot and arrested them and collected a few leaflets from them as well. Also Read – Heavy rain hits traffic, flightsIt may be mentioned that on Saturday, the police arrested three people including BJP Jalpaiguri district secretary Shubhankar Ghosh and Alipurduar district leader Raju Ghosh for allegedly possessing Rs 10 lakh cash in Alipurduar. Acting on a tip-off, police conducted a raid in a hotel in Alipurduar and picked up all three of them. The cops have recovered unaccounted cash from them which the leaders claimed to be party funds.
Kolkata: The Kolkata Municipal Corporation (KMC) on Monday collected as many as 13 fish samples from five markets in the city, to check for presence of formalin in them. There have been allegations of presence of formalin in fish imported from Andhra Pradesh.”We have collected 9 surveillance samples and 4 regulatory samples from some leading fish markets. We will conduct tests to find out whether there is presence of formalin. The report is expected to be available in two to three days,” Member, Mayor-in-Council (Health) Atin Ghosh said. Also Read – Naka checking to be stricter to rein in speed demonsIn case of regulatory samples that have been collected by undergoing certain formalities as per rules, the civic body can initiate cases if they find any irregularities in the samples.Among these samples, two have been collected from Manicktala Market, one from Poura Parna Bithika Market- Behala and another from S N Ray Market in Behala. Among the nine surveillance samples, six were collected from Entally Market and three from New Market.Formalin is a preservative that can lead to cancer if consumed over a period of time. The chemical can also cause nausea and other ailments in the short term. Also Read – Sowing activities on track with ample rain in S Bengal districtsIt may be mentioned that more than half the fish consumed in the city is procured from Andhra Pradesh.Officials of the state Fisheries department have been asked to visit wholesale markets across the city from Saturday, to collect samples that will be checked.According to the state Fisheries department stats, the city alone consumes around 235 tonnes of fish every day. Fish from Andhra Pradesh – mostly Rohu and Katla – accounts for around 135 tonnes of the total consumption. Of around 1.73 lakh tonnes of fish that Bengal imports from other states annually, Andhra accounts for around 1 lakh tonnes.The Assam government had already banned sale of fish from Andhra Pradesh, after lab tests detected formalin in some samples.”Banning of fish from Andhra will be difficult for Bengal. If we stop import, the deficit cannot be met by local production,” an official in the state Fisheries departmentsaid.
Kolkata: Shooting for Bengali TV serials resumed this morning in the city, a day after Chief Minister Mamata Banerjee held a meeting with the artistes and producers to end a deadlock over regularization of payment. The impasse between the Artists’ Forum and Welfare Association of Television Producers had stalled shoots for six days, forcing TV channels to air old episodes. Banerjee, after convening a meeting of representatives from both sides, told reporters yesterday that a conciliation committee has been set up with state Youth Affairs Minister Aroop Biswas as the chairman and veteran actor Soumitra Chatterjee as chief adviser to “look into the complaints”. Also Read – Rain batters Kolkata, cripples normal life She also assured the artistes and technicians that the newly formed committee will hold a meeting every month to ensure that they are not deprived of their basic rights. Among those who were present at the meeting at the secretariat yesterday were actor Prosenjit Chatterjee, the working president of the Artists’ Forum, Shrikant Mohta of Shree Venkatesh Films and Nispal Singh of Surinder Films. Talking to PTI today, Arindam Ganguly, the general secretary of Artists’ Forum, said all performers and technicians turned up at the studios for the shoot today as per “call time”. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killed “The conciliation committee’s first meeting will take place in two days’ time and hopefully we will solve all pending issues, including demand for overtime payment, in an amicable manner.” The Artists’ Forum had been demanding salaries by 15th of every month, hourly incentives for toiling over 10 hours and a 14-hour work limit every day. Leena Gangopadhyay, a script writer of TV soaps and one of the members of the conciliation committee, expressed confidence that the differences will be sorted out soon. “Now that the shooting has resumed, we are confident that all problems will be resolved sometime soon,” she said.
Kolkata: Abahan, Abarta and Bisharjan, the three eternal concepts relating to the advent of Goddess Durga with her entourage on earth, her five day stay here and her journey back to her abode, will be depicted interestingly through the lifecycle of a child at three Puja pandals in the city.A child is often considered as the embodiment of God. According to artist Anirban Das, who has come up with the unique idea of showcasing the concept through Durga Puja, said that the invocation of Goddess Durga is very similar to the birth of a child, who is also invoked by his/her parents. Also Read – Rain batters Kolkata, cripples normal lifeAbahan or invocation has become the theme of Dum Dum Tarun Dal, where models of various Gods and nymphs will be kept inside the Puja pandal, who will be celebrating the birth of a child. There will be symbolic representations of children through various depictions of flowers. “Every child is special but we fail to provide conducive atmosphere for a child to grow up. Many of the children are ill-treated in the society. We seek power from Goddess Durga to fight injustice and oppression, so that our world becomes a better place for these children,” Das said. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedHindustan Park Sarbojanin has adopted the theme of Abarta, where life’s journey would be depicted through various models inside the Puja pandal. They’ll show how the children are overburdened with studies and are forced to take part in the so called rat race. “People often force their children to take part in a mad race. We are trying to present how human lives have become complicated. A circus will be set up through various models to show how we all have become mere stage players. There will also be models of clowns. The idol of Goddess Durga will be portrayed on an Ektara, a one-string musical instrument,” Artist Das said. The Ektara is closely associated with the life of a folk artiste who believes in simple living. This very concept had prompted the artist to put Goddess Durga on the backdrop of the instrument. The artist is trying to highlight that taking part in a mad race of earning money does not always bring fortune for the children, Das said. Bisharjan has become the Puja theme for Chetla Agrani this year, where a palatial building will be constructed which will help people understand the futility of existence. A pond will also be created in front of the idol in such a manner that the visitors can see the Goddess’ reflection in it. According to the artist, the pond serves as a symbol where people can shed their sins.
More and more people are gradually viewing social media platforms like Facebook and Twitter and enterprise social media LinkedIn negatively than in the past, an interesting study has revealed.The team from American Consumer Satisfaction Index (ASCI) which tracks opinions of search engines, news outlets, social media sites and other ‘e-businesses’ found that consumers view Facebook, Twitter and LinkedIn more negatively than in years past.Facebook and Twitter saw the largest declines – at nine per cent and eight per cent, respectively. An increase in restless user base on some of the largest social media sites is forcing advertisers and the businesses who run them to put their money elsewhere.The declines are driven in part by the presence of advertising on services that are still regarded as “free”. Consumers have not fully accepted advertising as a necessary cost for online services they have come to expect as free. There is little companies can do to change that perception beyond making sure that those advertisements are relevant and non-disruptive, the report said.Facebook was mired in controversy over “curated” news where it was accused of political bias in its “trending news” section after news broke that stories from politically conservative sources were sidelined. However, the company denied such a bias.Earlier this year, reports said that Twitter irked many users when it tweaked its newsfeed from a chronological system to a new algorithm based system. It has also failed to keep pace with ever-evolving social apps including Snapchat, Imgur and Instagram.“It’s impossible for global brands with massive user bases to like Facebook and Twitter to keep everyone happy,” experts added.