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As we can know, a new technique that can change plastic's molecular structure to help it cast off heat is a promising step in that direction. Advanced plastics could usher in lighter, cheaper, more energy-efficient product components, including those used in vehicles, LEDs and computers -- if only they were better at dissipating heat. Developed by a team of University of Michigan researchers in materials science and mechanical engineering and detailed in a new study published in Sciene Advances, the process is inexpensive and scalable. The concept can likely be adapted to a variety of other plastics. In preliminary tests, it made a polymer about as thermally conductive as glass -- still far less so than metals or ceramics, but six times better at dissipating heat than the same polymer without the treatment."Plastics are replacing metals and ceramics in many places, but they're such poor heat conductors that nobody even considers them for applications that require heat to be dissipated efficiently," said Jinsang Kim, U-M materials science and engineering professor. "We're working to change that by applying thermal engineering to plastics in a way that hasn't been done before." The process is a major departure from previous approaches, which have focused on adding metallic or ceramic fillers to plastics. This has met with limited success; a large amount of fillers must be added, which is expensive and can change the properties of the plastic in undesirable ways. Instead, the new technique uses a process that engineers the structure of the material itself. Plastics are made of long chains of molecules that are tightly coiled and tangled like a bowl of spaghetti. As heat travels through the material, it must travel along and between these chains -- an arduous, roundabout journey that impedes its progress. The team -- which also includes U-M associate professor of mechanical engineering Kevin Pipe, mechanical engineering graduate researcher Chen Li and materials science and engineering graduate student Apoorv Shanker -- used a chemical process to expand and straighten the molecule chains. This gave heat energy a more direct route through the material. To accomplish this, they started with a typical polymer, or plastic. They first dissolved the polymer in water, then added electrolytes to the solution to raise its pH, making it alkaline. The individual links in the polymer chain -- called monomers -- take on a negative charge, which causes them to repel each other. As they spread apart, they unfurl the chain's tight coils. Finally, the water and polymer solution is sprayed onto plates using a common industrial process called spin casting, which reconstitutes it into a solid plastic film. The uncoiled molecule chains within the plastic make it easier for heat to travel through it. The team also found that the process has a secondary benefit -- it stiffens the polymer chains and helps them pack together more tightly, making them even more thermally conductive. "Polymer molecules conduct heat by vibrating, and a stiffer molecule chain can vibrate more easily," Shanker said. "Think of a tightly stretched guitar string compared to a loosely coiled piece of twine. The guitar string will vibrate when plucked, the twine won't. Polymer molecule chains behave in a similar way." Pipe says that the work can have important consequences because of the large number of polymer applications in which temperature is important. "Researchers have long studied ways to modify the molecular structure of polymers to engineer their mechanical, optical or electronic properties, but very few studies have examined molecular design approaches to engineer their thermal properties," Pipe said. "While heat flow in materials is often a complex process, even small improvements in the thermal conductivities of polymers can have a large technological impact." The team is now looking at making composites that combine the new technique with several other heat dissipating strategies to further increase thermal conductivity. They're also working to apply the concept to other types of polymers beyond those used in this research. A commercial product is likely several years away. "We're looking at using organic solvents to apply this technique to non- water soluble polymers," Li said. "But we believe that the concept of using electrolytes to thermally engineer polymers is a versatile idea that will apply across many other materials." Ref.KY59-GW5BTF50K00KY59-LMR040-0700-40F8-20100EW

Printed organic photodetectors and large-area image sensors company, Isorg, has announced that its first large-sized high-resolution (500dpi) flexible plastic fingerprint sensor, co-developed with FlexEnable, won the 2017 Best of Sensors Expo – Silver Applications Award. The high-resolution, ultra-thin, 500dpi flexible image sensor (sensitive from visible to near infrared) offers system integrators advantages in performance and compactness. Its ability to conform to three-dimensional shapes sets it apart from conventional image sensors. The device provides dual detection: fingerprinting as well as vein matching. Due to its large-area sensing and high-resolution image quality, the device is highly suited to biometric applications from fingerprint scanners and smartcards to mobile phones, where accuracy and robustness as well as cost-competiveness are key. Several biometric solution providers have sampled the flexible image sensor, verifying its readiness for deployment in products and compliance with FBI Image Quality Standards (IQS). “Isorg is very honoured to have received an international award for our groundbreaking high-resolution flexible image sensor technology whilst attending the most important global trade event dedicated to sensor innovations,” said Emmanuel Guerineau, General Manager and CFO at Isorg. “We are delighted to have collaborated with FlexEnable to produce the world’s first printed electronics image sensor that overcomes the limitations of traditional sensors. Biometric solution providers will be able to take advantage of the key differentiating factors that our technology brings, such as customised formats in large and small sizes, and easy integration. We see these opening up new opportunities across multiple applications.” Isorg is planning to launch high-volume production of the flexible image sensor at its new plant in Limoges, France, in order to support its large-scale commercialisation in the global biometrics market. The global biometrics hardware market is expected to grow from $3.9bn (approximately £2.99bn) in 2016 to $6.2bn (approximately £4.76bn) by 2021, according to the Yole Développement report on ‘Sensors for Biometry and Recognition 2016′. Central to the 500dpi flexible image sensor is an Organic Photodiode (OPD), a printed structure developed by Isorg that converts light into current – responsible for capturing the fingerprint. Isorg also developed the readout electronics, the forensics quality processing software and the optics to enable seamless integration in products. FlexEnable, a specialist in developing and industrialising flexible organic electronics, developed the Organic TFT backplane technology, an alternative to amorphous silicon. This partnership between the two companies began in Q4 2013. “We are delighted that the large area flexible fingerprint sensor we developed with Isorg has been recognised with such a prestigious award. Thanks to being thin, light and glass-free, the sensor can be conformed to almost any surface to enable new form factors and use cases not possible with conventional fingerprint sensors,” said Paul Cain, Strategy Director at FlexEnable. Designed on a large area (3x3.2”; 7.62x8.13cm) plastic substrate, the flexible image sensor is ultra-thin (300µ), therefore remarkably lightweight, compact and highly resistant to shock. Sensors Expo and Conference, held in San Jose, California, is the largest gathering of engineers and engineering professionals involved in sensors and sensing-related technologies. For over 30 years, it has welcomed more than 6,400 professionals from across the US and over 40 countries to explore today’s sensor technologies and find the solutions to tomorrow’s sensing challenges. The Best of Sensors Expo Awards are announced in conjunction with Sensors Online, a leading resource and authority on sensing, communication and control. The awards are designed to spotlight the advances in both innovations and real-world applications of sensors. Ref.NOIL2SM1300A-GDCMT9V022IA7ATCMT9V011

The simplest semiconductor component, the diode, has an astonishing number of applications that are enabled by a number of practical and unique types of diodes that are vital in modern electronics.Now let's get start to learn about diodes.   Applications of Diodes While only two pin semiconductor devices, there are a number of applications of diodes that are vital in modern electronics. Diodes are known for only allowing current to move in one direction through the component.   This lets a diode acts as a one-way valve, keeping signals where they need to be or routing them around components. While diodes only let current move in one direction, each type of diode acts differently, making a number of useful applications for diodes.   Some of the typical applications of diodes include:   ·  Rectifying a voltage, such as turning AC into DC voltages ·  Isolating signals from a supply ·  Voltage Reference ·  Controlling the size of a signal ·  Mixing signals ·  Detection signals ·  Lighting ·Lasers diodes   Power Conversion One significant application of diodes is to convert AC power to DC power. A single diode or four diodes can be used to transform 110V household power to DC by forming a half-way (single diodes) or a full-wave (four diodes) rectifier. A diode does this by allowing only half of the AC waveform to travel through it. When this voltage pulse is used to charge a capacitor, the output voltage appears to be a steady DC voltage with a small voltage ripple.   Using a full wave rectifier makes this process even more efficient by routing the AC pulses so both the positive and negative halves of the input sine wave are seen as only positive pulses, effectively doubling the frequency of the input pulses to the capacitor which helps keep it charged and deliver a more stable voltage. Diodes and capacitors can also be used to create a number of types of voltage multipliers to take a small AC voltage and multiply it to create very high voltage outputs. Both AC and DC outputs are possible using the right configuration of capacitors and diodes.   Demodulation of Signals The most common use for diodes is to remove the negative component of an AC signal so it can be worked with easier with electronics. Since the negative portion of an AC waveform is usually identical to the positive half, very little information is effectively lost in this process. Signal demodulation is commonly used in radios as part of the filtering system to help extract the radio signal from the carrier wave.   Over-Voltage Protections Diodes also function well as protection devices for sensitive electronic components. When used as voltage protection devices, the diodes are non-conducting under normal operating conditions but immediately short any high voltage spike to ground where it cannot harm an integrated circuit. Specialized diodes called transient voltage suppressors are designed specifically for over-voltage protection and can handle very large power spikes for short time periods, typical characteristics of a voltage spike or electric shock, which would normally damage components and shorten the life of an electronic product.   Current Steering The basic application of diodes is to steer current and make sure it only flows in the proper direction. One area where the current steering capability of diodes is used to good effect is in switching from power from a power supply to running from a battery. When a device is plugged in and charging, for example, a cell phone or uninterruptible power supply, the device should be drawing power only from the external power supply and not the battery and while the device is plugged in the battery should be drawing power and recharging. As soon as the power source is removed, the battery should power the device so no interruption in noticed by the user.   Ref. MN3306 MURB1520 SBG1030L-T-F

The US Department of Energy (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab) has detailed a living laboratory test of solid-state lighting (SSL) and controls on a 40,000-ft2 floor in a New York commercial office building. Berkeley Lab worked with the Building Energy Exchange (BEEx) on the LED lighting project that also included comprehensive light and occupancy sensors along with connected window shade controls. Berkeley Lab believes the work will speed market adoption of smart lighting and the BEEx will use the work to further its educational mission, serving lighting designers and specifiers that are working on commercial spaces.Lately, much of our coverage about smart lighting and the Internet of Things (IoT) has been focused on what lighting-based connectivity can offer in supporting new applications and services such as indoor positioning, security, asset tracking, and more. For example, Acuity Brands said earlier this year that it has deployed indoor positioning technology in 20 million ft2 of retail space. The IoT hype can make it easy to forget that networked control of lighting and shades confined to a space such as an office floor can deliver tremendous benefits in energy used.Still, roadblocks to more smart lighting installations remain. “Context matters when it comes to figuring out where the market barriers are with respect to contractors, facility managers, and office workers — isolated tests in a laboratory environment are often not enough,” said Eleanor Lee. “Reducing stakeholders’ uncertainty about performance and occupant response in a real-world setting can be critical to accelerating market adoption.” Lee is the Berkeley Lab scientist that led the New York project intended to document the benefits of smart lighting in a working office space — thus the characterization as a living lab. Berkeley Lab and BEEx collaborated on an office smart lighting trial in New York City that combined SSL with sensors and window shade controls. Indeed, the project team monitored energy usage and other characteristics of the office space for a full year before the retrofit to SSL and controls took place. BEEx acted as the local manager of the project.As the nearby photo illustrates, the retrofit replaced fluorescent T5 lighting with dimmable LED fixtures delivering direct and indirect lighting. The floor-to-ceiling windows received automated shades. And connected sensors spread throughout the mostly-open space can detect localized light levels and occupancy.The test further considered thermal elements of the space given that the ubiquitous windows and daylight can heat a space. The test included the use of linear slot diffusers along the top of the windows that can mitigate rising temperatures. And underfloor air distribution (UFAD) diffusers were used to improve airflow and allow for localized control. Thermal imaging was used to document acceptable temperatures throughout the retrofitted space.The smart lighting project sought to balance the benefits of natural light with visual and thermal comfort and provide workers with enjoyable views when possible. Shades had to be lowered at times to mitigate glare but could be opened at other times, both reducing the need for artificial lighting and fully revealing views for the office.The study focused on the 40-ft perimeter zone of the office floor. Compared to the measured baseline, the electricity required for lighting dropped 79% over the course of six months in which BEEx has monitored the installation. Peak electrical demand dropped 74%.The study did not measure energy dedicated to powering the HVAC (heating, ventilation, and air conditioning) system in the space. But the researchers did estimate the impact on HVAC energy and also projected the measured data to suggest an entire building retrofit would have delivered savings of $730,000 per year. Based on installation cost of $3–$10 per square foot, an entire building project would pay back in 3–12 years.BEEx will take the results of the project to help the lighting community with tools and other resources. “Using everything we learned on this project,  we've developed a series of tools that will really help the engaged design professional or building owner make better decisions about lighting system upgrades, and avoid the common pitfalls on the road to a high-performance office space,” said Yetsuh Frank, BEEx managing director of strategy and programs.The Berkeley Lab has not been as involved in the SSL sector as has the DOE Pacific Northwest National Laboratory (PNNL). PNNL has been behind many of the DOE Caliper and Gateway projects. We have covered many of those reports such as a recent Gateway report on four common indoor lighting applications.Still, the Berkeley Lab is adding to the DOE’s SSL initiative. About a year back we reported on a Berkeley project involving solar-powered LED lighting outdoors where the researchers said such lighting could create 2 million jobs in developing regions. Ref.591-2201-013F591-2001-013F 

(Integrated microscale flow batteries could power and cool future three-dimensional chip stacks.). Tightly packed electronic components generate a lot of heat. Tiny redox flow batteries will beneath supplying energy also dissipating the heat they produce. Researchers at ETH Zurich and IBM Research Zurich have built a tiny redox flow battery. This means that future computer chip stacks – in which individual chips are stacked like pancakes to save space and energy – could be supplied with electrical power and cooled at the same time by such integrated flow batteries. In a flow battery, an electrochemical reaction is used to produce electricity out of two liquid electrolytes, which are pumped to the battery cell from outside via a closed electrolyte loop. The chips are effectively operated with a liquid fuel and produce their own electricity. As the scientists use two liquids that are known to be suitable both as flow-battery electrolytes and as a medium to also effect cooling, excess heat can also be dissipated from the chip stack via the same circuit. The battery is only around 1.5 millimetres thick. The idea would be to assemble chip stacks layer by layer: a computer chip, then a thin battery micro-cell that supplies the chip with electricity and cools it, followed by the next computer chip and so on. Record-high outputPrevious flow batteries (see box) are usually large scale and used mainly in stationary energy storage applications, for instance in combination with wind farms and solar power plants, where they temporarily store the energy produced there so it can be used at a later time. These are the first scientists to build such a small flow battery so as to combine energy supply and cooling. The output of the new micro-battery also reaches a record-high in terms of its size: 1.4 watts per square centimetre of battery surface. Even if you subtract the power required to pump the liquid electrolytes to the battery, the resulting net power density is still 1 watt per square centimetre. In an experiment, the electrolyte liquids are actually able to cool a chip. They are even able to dissipate heat amounts many times over what the battery generates as electrical energy (which is converted into heat while the chip is in operation). Channel system optimised with 3D printingThe most serious challenge in constructing the new micro-flow batteries was to build them in such a way that they are supplied with electrolytes as efficiently as possible while at the same time keeping the pumping power as low as possible. It was important to find the ideal compromise. The electrochemical reactions in the battery occur in two thin and porous electrode layers that are separated by a membrane. The scientists used 3D-printing technology to build a polymer channel system to press the electrolyte liquid into the porous electrode layer as efficiently as possible. The most suitable of the various designs tested proved to be one made of wedge-shaped convergent channels. Interesting for large systems, tooThe scientists have now provided an initial proof-of-concept for the construction of a small flow battery. Although the power density of the new micro-flow battery is very high, the electricity produced is still not entirely sufficient to operate a computer chip. In order for the flow battery to be used in a chip stack, it must be further optimised by industry partners. The new approach is also interesting for other applications: in lasers, for example, which have to be supplied with energy and cooled; or for solar cells, where the electricity produced could be stored directly in the battery cell and used later when needed. The system could also keep the operating temperature of the solar cell at the ideal level. In addition, large flow batteries could also be improved with the optimised approach of forcing the electrolyte liquids through the porous electrodes. Ref.ML-2020/H1CNLC-RD1217P

Engineers at the University of Maryland have invented an entirely new kind of battery. It is bio-compatible because it produces the same kind of ion-based electrical energy used by humans and other living things.In our bodies, flowing ions (sodium, potassium and other electrolytes) are the electrical signals that power the brain and control the rhythm of the heart, the movement of muscles, and much more. In traditional batteries, the electrical energy, or current, flows in form of moving electrons. This current of electrons out of the battery is generated within the battery by moving positive ions from one end (electrode) of a battery to the other. The new UMD battery does the opposite. It moves electrons around in the device to deliver energy that is a flow of ions. This is the first time that an ionic current-generating battery has been invented. "My intention is for ionic systems to interface with human systems," said Liangbing Hu, the head of the group that developed that battery. Hu is a professor of materials science at the University of Maryland, College Park. He is also a member of the University of Maryland Energy Research Center and a principal investigator of the Nanostructures for Electrical Energy Storage Energy Frontier Research Center, sponsored by the Department of Energy, which funded the study. "So I came up with the reverse design of a battery," Hu said. "In a typical battery, electrons flow through wires to interface electronics, and ions flow through the battery separator. In our reverse design, a traditional battery is electronically shorted (that means electrons are flowing through the metal wires). Then ions have to flow through the outside ionic cables. In this case, the ions in the ionic cable -- here, grass fibers -- can interface with living systems." The work of Hu and his colleagues was published in the July 24 issue of Nature Communications. "Potential applications might include the development of the next generation of devices to micro-manipulate neuronal activities and interactions that can prevent and/or treat such medical problems as Alzheimer's disease and depression," said group member Jianhua Zhang, PhD, a staff scientist at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health in Bethesda, Md. "The battery could be used to develop medical devices for the disabled, or for more efficient drug and gene delivery tools in both research and clinical settings, as a way to more precisely treat cancers and other medical diseases, said Zhang, who performed biological experiments to test that the new battery successfully transmitted current to living cells.. "Looking far ahead on the scientific horizon, one hopes also that this invention may help to establish the possibility of direct machine and human communication," he said. Bio-compatible, bio-material batteries Because living cells work on ionic current and existing batteries provide an electronic current, scientists have previously tried to figure out how to create biocompatibility between these two by patching an electronic current into an ionic current. The problem with this approach is that electronic current needs to reach a certain voltage to jump the gap between electronic systems and ionic systems. However, in living systems ionic currents flow at a very low voltage. Thus, with an electronic-to-ionic patch the induced current would be too high to run, say, a brain or a muscle. This problem could be eliminated by using ionic current batteries, which could be run at any voltage. The new UMD battery also has another unusual feature -- it uses grass to store its energy. To make the battery, the team soaked blades of Kentucky bluegrass in lithium salt solution. The channels that once moved nutrients up and down the grass blade were ideal conduits to hold the solution. The demonstration battery the research team created looks like two glass tubes with a blade of grass inside, each connected by a thin metal wire at the top. The wire is where the electrons flow through to move from one end of the battery to the other as the stored energy slowly discharges. At the other end of each glass tube is a metal tip through which the ionic current flows. The researchers proved that the ionic current is flowing by touching the ends of the battery to either end of a lithium-soaked cotton string, with a dot of blue-dyed copper ions in the middle. Caught up in the ionic current, the copper moved along the string toward the negatively charged pole, just as the researchers predicted. "The microchannels in the grass can hold the salt solution, making them a stable ionic conductor," said Chengwei Wang, first author of the paper and a graduate student in the Materials Science and Engineering department at the University of Maryland in College Park. However, the team plans to diversify the types of ionic current electron batteries they can produce. "We are developing multiple ionic conductors with cellulose, hydrogels and polymers," said Wang. This is not the first time UMD scientists have tested natural materials in new uses. Hu and his team previously have been studying cellulose and plant materials for electronic batteries, creating a battery and a supercapacitor out of wood and a battery from a leaf. They also have created transparent wood as a potentially more energy-efficient replacement for glass windows. Creative Work Ping Liu, an associate professor in nanoengineering at the University of California, San Diego, who was not involved with the study, said: "The work is very creative and its main value is in delivering ionic flow to bio systems without posing other dangers to them. Eventually, the impact of the work really resides in whether smaller and more biocompatible junction materials can be found that then interface with cells and organisms more directly and efficiently." Source:University of Maryland Ref.ML-621S/ZTNMS412FE-FL26E