Fujitsu Introduces First 4Channel HDMI Connector Ports

first_imgFujitsu LTD – Embedded FRAM w/4-Channel HMDI Ports This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Fujitsu Introduces First 4-Channel HDMI Connector Ports (2007, November 14) retrieved 18 August 2019 from https://phys.org/news/2007-11-fujitsu-channel-hdmi-connector-ports.html In a blink of an eye Fujitsu has solved the costly problem of having to have separate memory on each of the HDMI ports. Fujitsu has produced the first embedded FRAM for digital TV that allows simultaneous use of a 4-Channel HDMI connector ports. The HDMI connector ports are used for running DVD recorders, camcorders, video gaming consoles, that store high resolution data and are read by audio visual devices when used with digital televisions. In use the new Fujitsu LSI in digital TVs allows high-speed factory programming of Expanded Display Identification display data. This breakthrough provides a cost saving in the overall production by reducing the number of the parts and reducing mounting space. In practice the evolution in HDMI, a digital multi-media interface has created high-quality video and audio output. The HDMI connector when used allows devices that create output to read the display data, like the display resolution and then automatically adjusts their output to produce the best display. The memory function for display devices which need four EPROM cells can now be handled by one cell. The key specifications are a memory capacity of 256-byte. The interface is DDC 4-Channel. The package is TSSOP 16-pin. The key savings besides parts and space is the reduced labor costs involved in the factory programming process. In turn this will potentially reduce the costs of producing digital televisions. Fujitsu is a leader in the field of IT and communication solutions headquartered in Tokyo, Japan with offices around the world. Fujitsu plans to demonstrate and show the innovation named MB85RF402 at the Embedded Technology Trade Show on November 14-17, 2007 in Yokohama, Japan. It is currently available for sample shipments and has a million unit per month sales target. Fujitsu has introduced the world´s first embedded FRAM for digital TVs that allow simultaneous use of a 4-Channel HDMI connector ports. The innovation will reduce the number of pars, mounting space and programming labor costs. It is expected to reduce the costs of digital TVs. New HDMI Chip Enables High Definition Display of Standard Definition Video Content and Digital Photos on HDTV Explore furtherlast_img read more

Crystals take a chill pill A thermomechanical theory of lowtemperature melting

first_img Copyright 2012 Phys.org 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. (Phys.org) — Virtual melting is a phase transition phenomenon associated with solid-solid phase transformation and relaxation of nonhydrostatic stresses and other effects in HMX explosives, as well as with crystal-crystal and crystal-amorphous phase transformation under high pressure. Since its initial formulation by Iowa State University Professor Valery I. Levitas and coworkers, virtual melting has been estimated to occur at 100 – 1000 °K below the material’s equilibrium melt temperature. Recently, however, Levitas and University of Texas Associate Professor Ramon Ravelo proposed a new deformation mechanism on which melting can occur at temperatures 4000 °K lower than the equilibrium melt temperature in materials subjected to high deviatoric stresses (where stress components vary by direction, and which control the degree of body distortion) in a shock wave. In addition, they’ve developed a novel thermomechanical theory of melting that predicts extremely large reduction in melting temperature. 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. Their next step, Levitas explains, was determining material parameters for a developed theory and application it to the specific melting process: While thermodynamic theory is quite universal and is applicable to any material, for some materials and loading conditions reduction in melting temperature can be small and for others very large. “This study was done through our synergistic collaboration: Ramon gave me parameters determined from his atomistic simulations for loading of copper and aluminum in several directions. “I then made thermodynamic predictions of the reduction in melting temperature for these specific materials.”There were also significant challenges in confirming virtual melting by large-scale molecular dynamics simulations. “Thermodynamic theory predicted how much melting temperature can be reduced due to uniaxial versus hydrostatic loading” Levitas explains. “For very high pressure this reduction was drastic: about 10,000 °K. The thermodynamic approach has important advantages in that it’s universal – for example, it’s not limited to specific materials and atomic structure. However, thermodynamics never says that some process will occur, but only that it can occur – that it’s thermodynamically admissible.”In contrast, Levitas notes, molecular dynamics simulations are performed for a specific material and atomic structure and interaction, but they reproduce all actual physical processes. “It may happen that while melting is possible from the thermodynamic point of view, it does not occur due to kinetic reasons or because other processes – such as dislocation plasticity or twinning – more rapidly release elastic stresses. Thus, one of the challenges in molecular dynamics simulations was to conceptually prove the existence of the virtual melting, which was done for the first time. Another challenge was to prove that the observed disordered state is indeed melt rather than an amorphous solid. Next, we had to investigate which parameters promote the melting, how actual melting temperature depends on them, and identify the lowest melting temperature.” Addressing these challenges required a range of insights, innovations and techniques. “I believe that the main insights and innovations were in our development of a combined thermodynamic and molecular dynamics approach, as well as in the proof of virtual melting existing in a shock wave several thousand degrees Kelvin below the melting temperature,” Levitas says. “Also, our results further support the idea that the virtual melting is a general phenomenon with various realizations.” While they previously suggested virtual melting as the mechanism of crystal-crystal phase transformation, amorphization and sublimation, here the scientists found that it also can serve as a mechanism of plastic deformation. “Lastly, since the thermodynamic features of the virtual melting here and in previous papers on phase transformations are quite similar, our first molecular dynamics confirmation of the virtual melting indirectly supports the plausibility of the virtual melting as an intermediate stage for phase transformations.”Levitas outlines how their findings impact nuclear explosions, meteorite impacts, and planned experiments in large laser facilities. “Virtual melting can compete with traditional mechanisms of plastic flow only at very high strain rates. Such conditions can be satisfied during nuclear explosions and meteorite impacts, which is why our results may be utilized for simulation of these phenomena.” Introducing new and completely unexpected deformation mechanisms, he adds, may also lead to essential progress in their understanding and predictive modeling.“The importance of such high strain rate regimes,” Levitas continues, “is supported by the fact that several laboratories around the world are now developing corresponding facilities for their experimental studies – and our results may find experimental confirmation in such studies. Finally,” Levitas notes, “due to the complexity of interpreting experimental results under such extreme conditions, it’s always good to have an idea about which phenomena could be found – and our virtual melting process is one of them.’Levitas also describes other areas of research and technology that might benefit from their findings. “In the current paper, virtual melting was conceptually confirmed by molecular dynamics simulations for the most unexpected case of metals, like copper and aluminum.” In these metals, traditional plasticity is very pronounced, which is why extremely high strain rates are required to activate an alternative mechanism like virtual melting. Since thermodynamic consideration is quite generic, this mechanism is expected in many other materials. “For materials with suppressed plasticity – for example, ceramics, high-strength alloys, or complex organic compounds – much lower strain rates may be required,” Levitas points out. “Then the virtual melting may play part in more traditional high-strain rate fields, like penetration of the projectile in a target in armor ceramic, propagation of shock waves, behavior of explosive materials, and deformation in shear bands.”Regarding next steps in their research, notes Levitas, “We plan to extend our thermodynamic approach for arbitrary 3D loading – in particular for deformation under high pressure and shear strains. It can also be extended for amorphization and sublimation, which can be considered as mechanisms of stress relaxation. Applying a phase field approach to the phenomena discussed is another important task. Finally,” Levitas concludes, “in molecular dynamic simulations we’ll study polycrystalline metals and materials with suppressed plasticity.” Explore further Spatial configuration can spark deja vu, psychology study reveals More information: Virtual melting as a new mechanism of stress relaxation under high strain rate loading, PNAS August 14, 2012 vol. 109 no. 33 13204-13207, doi:10.1073/pnas.1203285109 Levitas and Ravelo began their investigation when Levitas gave a talk on virtual melting in 2005 at Los Alamos National Laboratory, and there met Ravelo. “Ramon was very critical and asked a lot of questions,” Levitas recounts to Phys.org. “He noted that in atomistic simulations of shock wave propagation in defect-free crystals, it had been observed that disordering occurred at the shock front at temperatures much below the melt temperature at the corresponding shock pressure along some directions – but along others, melting occurred at or above the melting temperature.” Moreover, Levitas adds, it was common wisdom at the time that amorphization occurs due to the high stresses generated at the shock front. “This led us to ask, is the pre-melting observed in atomistic simulations due to mechanical instabilities, such as strain-induced amorphization, which are not related to melting? Or it is indeed virtual melting? Which loading parameters control the melting? What is the lowest temperature at which melting can occur? These were tough questions,” Levitas acknowledges, “and we then started our collaboration, which after seven years has resulted in the current paper.”Levitas relates the main challenges they faced. “I needed to develop a thermodynamic theory of melting under uniaxial straining typical for shock waves.” At the time, known theories for melting under nonhydrostatic conditions – that is, when loading is different in different directions – considered thermodynamic equilibrium to be between melt and nonhydrostatically stressed solid. Reduction in melting temperature due to nonhydrostatic stresses was estimated to be just 1 °K. “This definitely did not sound promising,” Levitas continues. “In contrast, melting in our case represents a deformation process and thermodynamic theory for processes was not developed. I did my best to develop a general formal theory and apply it to the specific processes, which Ramon observed in molecular dynamics simulations. “Since Ramon and I have different backgrounds and consider phenomena from completely different positions, one of the most challenging problems was to understand each other and to make our concepts consistent. A few times I misunderstood how Ramon verbally describes results of atomistic simulations, and developed a theory for the wrong scenarios. For example,” Levitas illustrates, “one time I used wrong the video player to play his movie with atomistic simulations and mistakenly observed that melting occurs at the surface of the sample only. I found this very exciting and developed a theory for this scenario, since it sounds reasonable that if uniaxially loaded sample melts along all the surfaces, it would become hydrostatically loaded and further melting would be impossible.” (A) Atomic configuration of Cu slab shocked to a pressure of 160 GPa (red atoms are solid, blue are liquid); (B and C) pressure and temperature profiles, respectively, along the shock direction. The temperature is normalized by the equilibrium melt temperature TmðpÞ at the corresponding shock pressure along the profile. Copyright © PNAS, doi:10.1073/pnas.1203285109 Citation: Crystals take a chill pill: A thermomechanical theory of low-temperature melting (2012, August 21) retrieved 18 August 2019 from https://phys.org/news/2012-08-crystals-chill-pill-thermomechanical-theory.html Journal information: Proceedings of the National Academy of Scienceslast_img read more

Scientists work out way to use pulsars to provide self navigation to

first_img(Phys.org) —A trio of German space scientists has worked out a way to use pulsars as navigation aids for space vehicles traveling in the solar system. As they describe in their paper uploaded to the preprint server arXiv, the method relies on reading information from at least three pulsars to triangulate location information. Artist’s impression of Rosetta, if it navigated in deep space using pulsar signals. The characteristic time signatures of pulsars are used as natural navigation beacons to determine the position and velocity of the spacecraft. Credit: arXiv:1305.4842 [astro-ph.HE] More information: Autonomous Spacecraft Navigation With Pulsars, arXiv:1305.4842 [astro-ph.HE] arxiv.org/abs/1305.4842AbstractAn external reference system suitable for deep space navigation can be defined by fast spinning and strongly magnetized neutron stars, called pulsars. Their beamed periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location, the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. The unique properties of pulsars make clear already today that such a navigation system will have its application in future astronautics. In this paper we describe the basic principle of spacecraft navigation using pulsars and report on the current development status of this novel technology.via ArxivBlog Journal information: arXiv Citation: Scientists work out way to use pulsars to provide self navigation to spacecraft in solar system (2013, May 24) retrieved 18 August 2019 from https://phys.org/news/2013-05-scientists-pulsars-spacecraft-solar.html The current method of navigation for spacecraft is to send radio waves back to Earth—scientists can calculate its distance by noting how long the radio waves take to reach them. Unfortunately, that doesn’t help to figure out its angular position. Generally, that’s not a problem, however, because of the vast distances between objects in the solar system—it’s likely to become more of an issue in the future, though, as space travel becomes more common. What’s needed, scientists say, is a way for spacecraft to keep tabs on their position without assistance from Earth. That’s what the team in Germany has done, using pulsars as guides.Pulsars are strongly magnetized neutron stars that spin very rapidly. Because they spin, they appear to blink or pulse, hence their name. Scientists have suggested over the years that it might be possible to use them as navigational aids, but until recently, the equipment necessary to read and interpret such signals has been far too bulky to put aboard a space craft. Also, limited knowledge about pulsars has constrained their usefulness. The team from Germany says progress in both areas has now been made to such an extent that it should be possible to put such equipment aboard a space probe capable of keeping track of its position to within 5km.Pulsars emit two kinds of signals that can be useful, radiation or x-rays. Both are emitted in cycles so precisely timed that they are comparable to atomic clocks. The researchers estimate a space vehicle reading pulsar radiation signals with 21 cm waves, for example, would require an antenna 150 square meters—that’s still too big for practical purpose. For that reason, the team suggests a better approach would be to listen for x-rays. Optics have progressed to the point, they say, that a mirror on a space vehicle capable of hearing and interpreting them would weigh just 25 kilograms, small enough for actual use. That would be good enough, they claim, to allow a spacecraft to triangulate its position to within 5km.center_img Dead stars could be the future of spacecraft navigation © 2013 Phys.org 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.last_img read more

Pentanuclear iron catalyst oxidizes water

first_imgCredit: Masaya Okamura et al. (Phys.org)—Plants are able to convert sunlight into energy through photosynthesis. There is much interest in designing a system that mimics the photosynthetic process as an environmentally friendly way to produce energy from sunlight. One of the key reactions in photosynthesis is oxidizing water so that it breaks apart into its components, molecular oxygen (O2) and protons (H+). This reaction is catalyzed by photosystem II. Explore further Research into a synthetic alternative to photosystem II has yielded catalysts that, while helpful, are not as practical for industrial use. The ideal catalyst would be cheap, robust, and reusable. Several researchers from various institutions in Japan have developed a pentanuclear iron catalyst that has many of these features. This catalyst has a turnover frequency of 1,900 s-1. Its five electrochemically active sites give it redox flexibility. Its adjacent active sites promote O-O bond formation and, thus, low activation energy. Their work appears in Nature.When water is oxidized it produces O2, H+ and four electrons. In nature, including in photosystem II, whenever multiple electrons are involved in a redox process, it is better to have a catalyst that has multiple redox sites, or redox flexibility. In designing a pentanuclear iron catalyst, the authors thought it would have sufficient flexibility to promote electron exchange.A catalyst serves to lower the energy in the rate determining step. It is thought that the rate determining step in the oxidation of water is the formation of O-O bond. Masaya Okamura, et al. therefore included in their design a way to promote O-O bond formation. Indeed, quantum chemical studies demonstrated that when two oxygens bind to two of the core iron atoms, a transition state forms that results in the evolution of oxygen gas.Their pentanuclear complex is [FeII4FeIII(μ3-O)(μ-L)6]3+ where LH is 3,5-bis(2-pyridyl)pyrazole. Two iron atoms are coordinated to six atoms within the ligand structure while the three iron atoms within the core are coordinated to five atoms within the ligand stucture. Two of these core iron atoms are the active sites for the O-O bond formation.Electrochemical studies confirmed that the catalyst undergoes five sequentially occurring reversible one-electron redox reactions in which FeII converts to FeIII. Addition of water showed evidence of oxygen evolution which was then quantified using controlled potential electrolysis in a two-compartment cell separated by an anion-exchange membrane. Gas chromatography measured the amount of O2. The catalyst demonstrated a Faradaic efficiency of 96% based on a four electron process and proved to be highly stable.Electrochemical studies evidence a four-step one-electron oxidation cycle. Quantum chemical calculations of the system using density functional theory demonstrate a low energy barrier for the catalytic mechanism. Turnover frequency (TOF) was determined using the results of electrochemical measurements. The obtained TOF value was 1,900 s-1, which is 1,000 times greater than other reported iron-based catalysts.This experiment demonstrates an effective design for a catalyst that promotes the oxidation of water. However, before this catalyst can be truly practical at a larger scale, additional studies will need to work out how to lower the large overpotential (greater than 0.5 V) and change the medium from acetonitrile/water to purely water. More information: Masaya Okamura et al. A pentanuclear iron catalyst designed for water oxidation, Nature (2016). DOI: 10.1038/nature16529AbstractAlthough the oxidation of water is efficiently catalysed by the oxygen-evolving complex in photosystem II, it remains one of the main bottlenecks when aiming for synthetic chemical fuel production powered by sunlight or electricity. Consequently, the development of active and stable water oxidation catalysts is crucial, with heterogeneous systems considered more suitable for practical use and their homogeneous counterparts more suitable for targeted, molecular-level design guided by mechanistic understanding. Research into the mechanism of water oxidation has resulted in a range of synthetic molecular catalysts, yet there remains much interest in systems that use abundant, inexpensive and environmentally benign metals such as iron (the most abundant transition metal in the Earth’s crust and found in natural and synthetic oxidation catalysts). Water oxidation catalysts based on mononuclear iron complexes have been explored, but they often deactivate rapidly and exhibit relatively low activities. Here we report a pentanuclear iron complex that efficiently and robustly catalyses water oxidation with a turnover frequency of 1,900 per second, which is about three orders of magnitude larger than that of other iron-based catalysts. Electrochemical analysis confirms the redox flexibility of the system, characterized by six different oxidation states between FeII5 and FeIII5; the FeIII5 state is active for oxidizing water. Quantum chemistry calculations indicate that the presence of adjacent active sites facilitates O–O bond formation with a reaction barrier of less than ten kilocalories per mole. Although the need for a high overpotential and the inability to operate in water-rich solutions limit the practicality of the present system, our findings clearly indicate that efficient water oxidation catalysts based on iron complexes can be created by ensuring that the system has redox flexibility and contains adjacent water-activation sites. Citation: Pentanuclear iron catalyst oxidizes water (2016, February 24) retrieved 18 August 2019 from https://phys.org/news/2016-02-pentanuclear-iron-catalyst-oxidizes.htmlcenter_img Sophisticated enzyme-mimic enables efficient hydrogen production © 2016 Phys.org Journal information: Nature 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

Hydrogel 3D printing and patterning liquids with the capacitor edge effect PLEEC

first_img Journal information: Science Advances Hydrogels are three-dimensional (3-D) polymer networks that can retain large quantities of water in their swollen states for wide applications in bioengineering and materials sciences. Advanced hydrogel fabrication techniques are in development to meet user-specified requirements with substantial constraints placed on the physical and chemical properties of hydrogel precursors and printed structures. In a recent study, Jikun Wang and co-workers at the State Key Lab for Strength and Vibration of Mechanical Structures, Department of Engineering Mechanics, in China, proposed a new method of patterning liquids with the capacitor edge effect (PLEEC). The results are now published in Science Advances. In the present work, Wang et al. proposed PLEEC (patterning liquids with the capacitor edge effect) to pattern liquids with different physical and chemical properties. The method can be applied to a variety of crosslinking mechanisms among multiple materials. The scientists used a capacitor that was asymmetric in design to allow the construction of a real 3-D object than mere 2-D patterns built within two electrodes. Based on the new method, Wang et al. built the 3-D printing system, to provide proof-of-concept printed hydrogel structures including a hydrogel scaffold, hydrogel composite and hydrogel ionic devices in the study. Explore further Printed hydrogel structures using the PLEEC system. (A) Scaffold-structured hydrogel lattice. (B and C) PAAm and PNIPAM hydrogel composites. When the polymerized hydrogel composite is placed in hot water, the PNIPAM hydrogel tends to shrink so that fingers roll up. (D) Stretchable LED belt. LEDs work well when the belt is stretched to double its length and suffers 100 loading cycles. (E) Soft display device. Each LED can be lit independently. Photo credit: Jikun Wang, Xi’an Jiaotong University. Credit: Science Advances, doi: 10.1126/sciadv.aau8769 The PLEEC panel proposed in the study contained five layers, where the top layer (Teflon film) acted as a hydrophobic, insulating cover to separate the liquid from the upper electrode. When the scientists applied an electric field, the edge effect generated an electrostatic force that trapped the liquid atop the hydrophobic layer. Using the principle, the scientists designed liquid patterns with different shapes and sizes. For instance, the trapped blue ink formed patterns of an Angry Bird and the letters XJTU. In addition, the scientists used an array of line pixels to control and trap liquid independently. Furthermore, in an array of 10 x 10 pixels, the scientists were able to form a variety of liquid patterns such as lines, squares and musical notes. With further developed circuit control technology, additional complex liquid patterns could be designed and controlled using PLEEC. In this way, Wang et al. proposed a new PLEEC panel design to generate complex liquid patterns and transferred the concept to build a 3-D printing system as demonstrated. The technology has several advantages and offers significant versatility compared to the existing methods of hydrogel 3-D printing. As a proof-of-concept, they used a wide variety of hydrogels with varying physical or chemical properties in the system and showed the possibility of using materials with varying viscosity, either bonded physically or chemically to construct structures of interest. Multiple hydrogel materials could also be easily patterned to form a variety of soft and hard, to active and passive hydrogel composites. They assembled the ionically conductive hydrogels in a single-step curing process for ease, demonstrating excellent integrity and bonding properties. The researchers aim to improve the precision of the technique in the future and optimize the 3-D printing PLEEC setup to streamline rapid prototyping. The optimized method will enable dynamic applications in tissue engineering such as artificial tissues, soft metamaterials in materials science, soft electronics and soft robotics. Researchers develop a hydrogel for enhanced cell encapsulation and delivery More information: Jikun Wang et al. Hydrogel 3D printing with the capacitor edge effect, Science Advances (2019). DOI: 10.1126/sciadv.aau8769David J. Beebe et al. Functional hydrogel structures for autonomous flow control inside microfluidic channels, Nature (2002). DOI: 10.1038/35007047 A. Sidorenko et al. Reversible Switching of Hydrogel-Actuated Nanostructures into Complex Micropatterns, Science (2007). DOI: 10.1126/science.1135516 Wang et al. polymerized the 2-D hydrogel precursor patterns and stacked them layer-by-layer to form a 3-D structure thereafter. In the experimental setup, the liquids flowed across the designed electrodes to form liquid patterns trapped by the electric field. A transparent curing platform then approached the liquid pattern to polymerize it in the plane of printing using UV light. The scientists determined the printing speed of the PLEEC method by deducing the time of liquid patterning, which was in the order of 101s and the time of polymerization in the order of 102 s, comparable to the DLP technique. Based on the PLEEC process, Wang et al. designed a complete PLEEC 3-D printing system with seven parts: a mechanical module, PLEEC panel, solution-adding unit, a curing platform, curing unit, power supply and a control module. The scientists used the solution adding holes in the setup to squeeze the hydrogel solutions onto the PLEEC panel and a UV lamp in the curing unit to complete the in-house printing system. They regulated the power supply using the control unit to provide a low voltage for mechanical movement of the module and higher voltage—as high as 3000 V at 1 kHz to the PLEEC panel. In turn, Wang et al. operated the control module using a central computer to send instructions to all units. Using the in-house printing system, the scientists then designed a hydrogel composite containing different percentages of PAAm and PNIPAM solutions, which they polymerized in the shape of a human hand, followed by triggered thermoresponsive behavior to form the finger gestures of “GOOD” and “OK.” The scientists also used the same experimental setup to engineer stretchable LED belts and soft display devices, where each LED in the system could be independently lit. Principle of PLEEC. An asymmetric capacitor is separated by a dielectric layer. Credit: Science Advances, doi: 10.1126/sciadv.aau8769 Using the new patterning method, Wang et al. accomplished a resolution of 100 µm, while also allowing them to establish a complete 3-D printing system that combined patterning and stacking processes. The technique can be applied to a wide variety of hydrogels to overcome existing limits. In the work, the scientists demonstrated printed hydrogel structures including a hydrogel scaffold, a thermoresponsive hydrogel composite and an ionic high-integrity hydrogel display device. The proposed technique can offer rapid prototyping hydrogel devices with multiple compositions and complex geometries. Additive manufacture or 3-D printing is an effective tool to engineer highly structured, interconnected and porous architectures compared to conventional methods of casting, photomasking and electrospinning. Researchers have previously used 3-D printing to create highly porous hydrogel scaffolds for cell cultures, as biomimetic microchips to study disease, build artificial heterogeneous tissues in regenerative medicine and as biocompatible organs with high geometric precision. 3-D hydrogels are also used to build conductive composites for soft robotics. In particular, computer-aided design (CAD) in 3-D printing is suited to build highly programmed and user-specified hydrogel structures for applications in tissue engineering. Previously established methods for hydrogel printing conventionally include digital projection lithography (DLP), stereolithography (SLA) and direct ink writing (DIW). However, such methods are limited to patterning with photopolymerizable hydrogel precursors only. Similarly, in the DIW-printing method, hydrogel precursors are water-like and difficult to deposit unless their viscosity is increased with nanoclays, affecting the processing technique. Electric fields are another technique that have been used to control liquids via electrowetting, dielectrophoresis and lithography induced self-assembly. Although the techniques can control single droplets between electrodes for applications in cell culture, patterned wettability, microfluidics and patterning electronics, electric fields can only manipulate a single droplet at a time. As a result, the technique lacks massive-scale control of liquid droplets, with difficulty of their use in 3-D printing. Left: Hydrogel 3D printing process with PLEEC. (A and B) Patterning process. When liquids flow over the designed electrode, the liquid patterns are trapped by the electric field. (C) Polymerization process. The curing platform moves down to contact the liquid pattern, and the hydrogel solution is polymerized by UV light. (D) Resetting process. The curing platform moves upward together with the newly formed hydrogel layer. Right: Hydrogel 3D printing system with PLEEC. (A) System schematic. The system consists of seven parts: a mechanical module, a PLEEC panel, a solution-adding unit, a curing platform, a curing unit, a power supply, and a control module. (B) The in-house printing system. Photo credit: Jikun Wang, Xi’an Jiaotong University. Credit: Science Advances, doi: 10.1126/sciadv.aau8769 © 2019 Science X Network (A) Liquid patterns of four representative hydrogel precursors with different chemical and physical properties and polymerization into hydrogel via different polymerization methods. (B) Liquid patterns of four functional materials: temperature sensitive, biocompatible, ionically conductive, and molding materials. Photo credit: Jikun Wang, Xi’an Jiaotong University. Credit: Science Advances, doi: 10.1126/sciadv.aau8769 , Nature As a proof-of-concept the scientists trapped four hydrogel precursors using an electric field, to form diverse structures. For example, Wang et al. trapped 2-acrylamido-2-methylpropanesulfonic acid (AMPS) solution to form a yellow circle, which then polymerized into the PAMPS hydrogel on exposure to UV light. They then similarly trapped the acrylamide solution (AAm) to form a red square, which then polymerized into the PAAm hydrogel by heat. The two hydrogel precursors (AMPS and AAm) were water-like and difficult to control via any other technique to begin with. Wang et al. also formed a blue cross using the alginate solution, which then polymerized into a brittle alginate hydrogel via ion exchange, followed by a green triangle formed using the alginate/AAm solution, which polymerized into an alginate/AAm tough hydrogel by heat and ion exchange. Apart from hydrogel precursors, Wang et al. were able to trap functional materials similarly using the electric field to form yellow wavy lines using N-isopropyl acrylamide solution, polymerized into temperature-sensitive PNIPAM hydrogels. They then formed a red heart using a polyethylene glycol diacrylate solution (PEGDA) widely used in bioengineering applications, followed by the blue flash formed with trapped ionic liquid that was ionically conductive and non-volatile suited for stretchable ionic conductors. A green infinity loop shape resulted from trapped photosensitive resin widely used in 3-D printing. The scientists thus demonstrated how PLEEC could trap a wide variety of hydrogel solutions for large-scale liquid manipulation and hydrogel 3-D printing. The electric field was able to trap a line of water at 100 µm resolution, very close to that observed with DLP and SLA. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Hydrogel 3-D printing and patterning liquids with the capacitor edge effect (PLEEC) (2019, April 1) retrieved 18 August 2019 from https://phys.org/news/2019-03-hydrogel-d-patterning-liquids-capacitor.html , Science (A) Asymmetric capacitors with different shapes. The lower electrodes have double the widths of the upper electrodes. When the voltage is on, the liquid is trapped within the patterned region of the lower electrodes. (B) Liquid pattern in the shape of an angry bird. (C) Liquid pattern of four letters “X,” “J,” “T,” and “U.” (D) Liquid patterns of nine natural numbers by independently controlling line pixels. (E) Changeable liquid patterns in the same PLEEC panel by independently controlling 10 × 10 pixels. Photo credit: Jikun Wang, Xi’an Jiaotong University. Credit: Science Advances, doi: 10.1126/sciadv.aau8769last_img read more

Nothing to say on reintroduction of JU entrance tests Guv

first_imgKolkata: West Bengal Governor K N Tripathi today said he had “nothing to say” about the decision of Jadavpur University to reintroduce entrance tests in the Arts faculty, and said the varsity’s executive council was within its rights to lay down admission norms. “The admission committee has been formed by the EC, it has laid down certain norms to conduct admission tests (to six humanities streams). The tests will now be conducted as per the stipulated norms… I have nothing to say in this matter,” Tripathi, who is also the Chancellor of JU, said. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killed Tripathi was asked to comment about the decision of the EC to reintroduce admission tests to the six humanities subjects in undergraduate courses – English, Comparative Literature, Bengali, History, Political Science and Philosophy. On JU Vice-Chancellor Suranjan Das’s statement that he would ask Tripathi to relieve him and Pro-VC Pradip Ghosh of their responsibilities, the Governor said, “Let him (VC) come. I will take appropriate measure after talking to him and taking a view of the whole situation.” Also Read – Naihati: 10 councillors return to TMC from BJP Entrance tests to the six arts subjects will be held on different dates from July 21 to July 25. Students would be admitted based on the 50:50 formula – equal weightage on marks obtained in admission tests and in board examination, a decision which had originally been taken at the June 27 EC meeting and subsequently scrapped, before been reintroduced. JU Registrar Chiranjib Bhattacharya has said no external experts will be involved in the admission process, which will be conducted by faculty members.last_img read more

Another bridge collapses in Bengal none injured

first_imgKolkata: Within a month of the Majerhat bridge collapse here in West Bengal, that claimed three lives, an under construction bridge in South 24 Parganas collapsed on Monday, police said. “Part of the under construction bridge over Kalnagini river in Kawkdeep area collapsed at around 10 a.m. No one has been injured in the incident,” a state police officer said. “The reason of the collapse is yet to be ascertained. Senior officials have reached the spot,” he added. A portion of the Majerhat bridge in south Kolkata collapsed on September 4, killing three and injuring at least 19 others. Another canal bridge collapsed in Darjeeling district’s Siliguri on September 7, injuring a truck driver.last_img

Brain plays key role in gauging errors

first_imgThe key element in our decision-making that serves to both gauging errors and revising our approach is confidence, suggested a new study. The study, published in the journal Proceedings of the National Academy of Sciences, offers insights into the hierarchical nature of how we make choices over extended periods of time, ranging from medical diagnoses and treatment to the strategies we use to invest our money. “Overall, we found that the brain uses confidence to gauge errors and revise decision strategy. Specifically, the confidence in our initial assessments influences how we revisit them,” said Roozbeh Kiani, Assistant Professor, New York University. Also Read – ‘Playing Jojo was emotionally exhausting’“What is challenging about comprehending, why we make certain choices over long periods is to determine the true causes of the outcomes of our decisions,” explains Braden Purcell, researcher, New York University. To do so, the researchers devised an experiment in which subjects judged the net motion direction of multiple dots on a computer screen. The subjects’ judgments were recorded by gauging their eye movement toward one of several targets on the screen. Researchers discovered that when confident about motion direction, subjects attributed negative feedbacks to a change in the environment and quickly explored new targets.  Also Read – Leslie doing new comedy special with NetflixWhen the subjects were less confident, they counted negative feedbacks as partial evidence for an environment change but withheld exploring a new target until the sum of evidence which is confidence on error trials – reached a threshold, revealed the study. According to the researchers, optimal decision-makers should adjust the threshold for switching strategy based on the volatility of the environment.  They showed that subjects were quicker to explore new targets when changes in the environment happened more frequently.last_img read more

High on Creativity

first_imgThe seventh season of Winter/Festive edition of India Runway Week commenced at Thyagraj Stadium last Friday and continued till Sunday. The show opened with the designs of international Designer Bibi Russell under the name of “Rajasthali”. Day one was high on creativity, where experienced designers ruled the ramp.Bollywood Diva Soha Ali Khan walked the ramp for Designer Shweta Sarda who presented the glory of womanhood through her designs while Mugdha Godse and Mandana Karimi also walked the ramp for Designer Satomi by Rakam and Studio AV. Also Read – Add new books to your shelfThe second day of India Runway week Season 7 in association with Big Boy Toyz started  with college students doing the  ramp walk in  the designs of the students from Appejay Design Institute. Fashion designer Yoshita Yadav launched her bridal collection ‘Oudh’ under the label Yoshita Couture at India Runway Week on September 17. Bollywood actor Esha Gupta walked the ramp as the showstopper dressed in a beautiful Yoshita Yadav creation. The collection ‘Oudh’ was presented for the first time and consisted of pre bridal dresses apt for ceremonies like the sangeet, mehendi, and reception of an Indian wedding.  Also Read – Over 2 hours screen time daily will make your kids impulsiveThe bridal collection was inspired by the ethereal style legacy of Lucknow, as the name ‘Oudh’ suggests, the design of the collection took its inspiration from the architecture of the most flourishing and the richest period of the Awadhi history. It aims to revive the continuum of cultural legacy patronized by the Nawabs and the elite of Lucknow.Day 3 started with the show of five designers-  Shilpa Chourasia, Sana Khan, Var-Shi by Varun and Vidushi, Preatz by PreethiFazel, Abitie by Megha Mahendru.  Veteran Actress Sharmila Tagore walked ramp for Rohini Gugnani. She dazzled the show with the grace and dignity showcasing the splendid and grand Avadh era in her designs. Gugnani’s latest collection was an interesting play of concepts derived from the cities of Kanpur, Lucknow, Faizabad which redefined the glory of Avadh period in present time. Ethnicity is kept unscathed, mingling it with contemporary designs to make the collection fit for modern bride and Groom. “I am very humbled that Sharmila Tagore agreed to be the face of the collection as no one could else could have better presented the Nawabi elegance and style” says Rohini.The Grand finale of India Runway Week was by Designers Riddhi and Siddhi with their collection ‘English Country Gardens’.  The collection conjures up contemplative thoughts of romance and lazy summer days. The colour story has a diverse range of hues from onion pinks, peaches,off-whites, pale blue and brown. The silhouettes are long, fluid and layered for women and sharp yet easygoing for men.last_img read more

WB govt shifts Pak inmates to highsecurity cells

first_imgKolkata: The West Bengal government has shifted 14 Pakistani prisoners, lodged in two correctional homes here, to separate barracks and “high-security” cells, amid soaring tension between India and its western neighbour, a senior official said. The state government’s move comes days after a 50-year-old Pakistani convict was allegedly killed by fellow inmates in Rajasthan’s Jaipur Central jail. “Strict instructions have been issued to separate Pakistani inmates from others following the incident in Rajasthan jail. They have been shifted to high-security cells, where heavyweight prisoners, such as those arrested for American Center attack and Maoists have been staying,” the official of West Bengal Correctional Services said. Also Read – Bose & Gandhi: More similar than apart, says Sugata Bose A three-layered cordon has been set up for the security of the 14 prisoners, he said. “Most of these prisoners share a good rapport with their fellow inmates, but we cannot take risk in the wake of the Pulwama attack,” the official told PTI on Wednesday. Of the 14 inmates, four are lodged at Presidency Correctional Home in the city and the other 10 at Dum Dum Central Correctional Home, he said. “Some were jailed for flouting visa norms, while a few were waiting to be taken to other correctional homes. There are also others who were imprisoned for their involvement in criminal activities,” the state government official said. Along with the chief head warden, the head warders are keeping an eye on the cells, he said. “The Pakistani inmates will not be allowed to move out of the sensitive zones for now. Our officers are keeping a close watch on these cells round the clock,” he added.last_img read more