Engineering and Technology Updates

Engineering and Technology Updates

Mumbai Coastal Road: The Coast is Clear

While the world is seeing an unprecedented crisis with the pandemic, Mumbai is seeing a project that was only hitherto imagined. Municipal Corporation of Greater Mumbai (MCGM) is executing it. Today, the 29.80 km Mumbai Coastal Road Project (MCRP) is an under construction access-controlled expressway with a route connecting Princess Street Flyover in South Bombay with Kandivali in the northern suburbs. The completed work includes about 470 metres (m) or 25% of tunnelling work of one tunnel and reclamation of 105 hectares (ha) of the total 111ha. At present, the piling work, casting of piers and girders, construction of the ramp work at Marine Drive and tunnelling work are in progress. The road will extend the coast up to 100 meters inside the sea. Plans are afoot to reclaim 111-hectare area in the Arabian Sea which is 12 times the size of Oval Maidan at Mumbai’s Churchgate. Of the 111-hectare land reclamation required for the project so far, the civic body has completed about 100 hectares. Overall, the project is divided in two parts: Phase 1: The South End – From Princess Street flyover to Worli end of Bandra Worli Sea Link – a stretch of 9.98 km – to be executed by Municipal Corporation of Greater Mumbai – MCGM. Phase 2: The North End – From Bandra end of Bandra Worli Sea Link to Kandivali – to be executed by MSRDC. The 8-lane freeway, with 2-lanes reserved for BRTS corridor, will have 22 entries and exits, two earthquake resistant undersea tunnels of 3.4 km each at Girgaum Chowpaty and Malabar Hill, and 13 cross tunnels to be used for emergency. The entire stretch is expected to be ready by the end of 2023, if all goes well. In its first phase, a 9.98 km section from Princess Street flyover to the Worli end of the Bandra-Worli Sea Link, is expected to be completed by mid-2023. The Coastal Road will be built in two phases. The project will require the reclamation of 415 acres of land from the sea. Mavala, the Tunnel Boring Machine, has completed digging 500 meters of the coastal road tunnel. The TBM, with its diameter of 12.19-meters, is said to be the country’s biggest road tunnel boring machine. It weighs 2,300 tonnes and is 80-meters long. It is digging on an average of 8-10 meters per day and around 20 meters below the ground at the Priyadarshini park site. The country’s first undersea tunnel is a set of twin tunnels one for each carriageway. The length of each is 2.07 km from Priyadarshini park to Chotti Chowpatty at Marine drive, close to the landmark Chowpatty beach at Girgaon. From Malabar Hill to the Sea Link, the Coastal Road will mostly be built on reclaimed land, around 50-70 meters inside the sea. Green zones are developed alongside the freeway on reclaimed land for various public utilities like jogging & cycling tracks and gardens. Walking, jogging and cycling on the promenade will bring a different paradigm of urban comfort. The entire infrastructure shall be a visual delight for Worli. Flexible roads are also being constructed on reclaimed land. The substructure of intertidal area of interchanges are being constructed by Group Pile method followed by construction of Piers and Pier Cap by in situ casting. The pre-cast segments are erected by ground supported staging arrangements and post tensioned. The substructure of marine area of bridge and interchanges are constructed by monopile method followed by construction of piers and pier cap by insitu casting. The pre-cast segments are erected by use of launching girder tailor made for the project and then segments are post tensioned. What the BMC is doing is creating approach roads/dykes to reach the sea wall locations by filling of rocks. The sea wall core layer is being built for a certain length by dumping quarries into the sea by end tipping method. It is also placing rocks of specific sizes using excavators to a specific height of 4 meters above mean sea level.

Source: https://www.constructionweekonline.in/projects-tenders/18912-mumbai-coastal-road-the-coast-is-clear

Running Quantum Software on a Classical Computer

EPFL Professor Giuseppe Carleo and Matija Medvidovic, a graduate student at Columbia University and at the Flatiron Institute in New York, have found a way to execute a complex quantum computing algorithm on traditional computers instead of quantum ones. The specific “quantum software” they are considering is known as Quantum Approximate Optimization Algorithm (QAOA) and is used to solve classical optimization problems in mathematics; it’s essentially a way of picking the best solution to a problem out of a set of possible solutions. “There is a lot of interest in understanding what problems can be solved efficiently by a quantum computer, and QAOA is one of the more prominent candidates,” says Carleo. Ultimately, QAOA is meant to help us on the way to the famed “quantum speedup,” the predicted boost in processing speed that we can achieve with quantum computers instead of conventional ones. Understandably, QAOA has a number of proponents, including Google, who have their sights set on quantum technologies and computing in the near future: in 2019 they created Sycamore, a 53-qubit quantum processor, and used it to run a task it estimated it would take a state-of-the-art classical supercomputer around 10,000 years to complete. Sycamore ran the same task in 200 seconds. “But the barrier of “quantum speedup” is all but rigid and it is being continuously reshaped by new research, also thanks to the progress in the development of more efficient classical algorithms,” says Carleo. In their study, Carleo and Medvidovic address a key open question in the field: can algorithms running on current and near-term quantum computers offer a significant advantage over classical algorithms for tasks of practical interest? “If we are to answer that question, we first need to understand the limits of classical computing in simulating quantum systems,” says Carleo. This is especially important since the current generation of quantum processors operate in a regime where they make errors when running quantum “software,” and can therefore only run algorithms of limited complexity. Using conventional computers, the two researchers developed a method that can approximately simulate the behaviour of a special class of algorithms known as variational quantum algorithms, which are ways of working out the lowest energy state, or “ground state” of a quantum system. QAOA is one important example of such family of quantum algorithms, that researchers believe are among the most promising candidates for “quantum advantage” in near-term quantum computers. The approach is based on the idea that modern machine-learning tools, e.g. the ones used in learning complex games like Go, can also be used to learn and emulate the inner workings of a quantum computer. The key tool for these simulations are Neural Network Quantum States, an artificial neural network that Carleo developed in 2016 with Matthias Troyer, and that was now used for the first time to simulate QAOA. The results are considered the province of quantum computing, and set a new benchmark for the future development of quantum hardware. “Our work shows that the QAOA you can run on current and near-term quantum computers can be simulated, with good accuracy, on a classical computer too,” says Carleo. “However, this does not mean that all useful quantum algorithms that can be run on near-term quantum processors can be emulated classically. In fact, we hope that our approach will serve as a guide to devise new quantum algorithms that are both useful and hard to simulate for classical computers.”

Source: https://www.sciencedaily.com/releases/2021/08/210803121404.htm

Graphene Nano-Inks for Additive Manufacturing of Supercapacitors

Research led by Kansas State University’s Suprem Das, assistant professor of industrial and manufacturing systems engineering, in collaboration with Christopher Sorensen, university distinguished professor of physics, shows potential ways to manufacture graphene-based nano-inks for additive manufacturing of supercapacitors in the form of flexible and printable electronics. As researchers around the world study the potential replacement of batteries by supercapacitors, an energy device that can charge and discharge very fast — within few tens of seconds — the team led by Das has an alternate prediction. The team’s work could be adapted to integrate them to overcome the slow-charging processes of batteries. Furthermore, Das has been developing additive manufacturing of small supercapacitors — called micro-supercapacitors — so that one day they could be used for wafer-scale integration in silicon processing. “Additive manufacturing is fascinating, cost-effective, and has versatile design considerations,” Das said. The team has developed supercapacitors that have been tested for 10,000 cycles of charging and discharging cycles, a number that is promising to evaluate the reliability of these devices, Das said The team is also studying the versatility of these micro-supercapacitors by printing on mechanically flexible surfaces. For this, they used 20-micrometer-hin polyimide — plastic — substrates with high reliability. Das is highly interested in translating emerging materials to devices. Another advantage of Das’ invention is the green aspects of the research that he visualized through constructive discussions with Sorensen. When Das met Sorensen, he realized he could use his expertise in additive manufacturing to transform these materials into useful things; in this case, making tiny energy storage devices. Das is particularly interested in forming this synergistic collaboration with Sorensen because of the energy-efficient, highly scalable and chemical-free nature of the graphene production process and his own group’s graphene ink manufacturing process. Both of these processes are patented/patent-pending technologies and are industrially relevant, Das said. “We make high-quality, multilayer graphene by detonating fuel-rich mixtures of unsaturated hydrocarbons such as acetylene with oxygen in a multi-litre chamber,” Sorensen said. “Our patented method is simple requires very little energy, hence is ecologically benign; requires no toxic chemicals; and has been scaled up to yield high-quality, inexpensive graphene.” Graphene has been recognized as a wonder material with much potential because of its many superlative physical properties Many graphene manufacturing methods have been developed across the globe and graphene has been produced in ton quantities. Technologists, however, are well aware that graphene is not yet in the marketplace because none of these methods have had the right combination of economy, ecology and product quality to allow graphene to fulfil its potential. But both the methods of producing graphene and nano-inks pursued at Kansas State University are on target to address all of these requirements, according to Sorensen and Das.

Source: https://scitechdaily.com/graphene-nano-inks-for-additive-manufacturing-of-supercapacitors

Green Hydrogen: Focus on The Catalyst Surface

Hydrogen produced from renewable energy sources with the help of electric power is deemed a key to the energy transition: It can be used to chemically store wind and solar energy in a CO2-neutral way. Researchers have studied water electrolysis processes on the surface of an iridium oxide catalyst. Using energy from solar modules and wind turbines, water can be split by electrolysis into its constituents hydrogen and oxygen without producing any dangerous emissions. As the availability of energy from renewable sources varies when producing green, i.e. CO2-neutral, hydrogen, it is very important to know the behaviour of the catalysts under high loading and dynamic conditions. “At high currents, strong oxygen bubble evolution can be observed on the anode, which aggravates measurement. It has made it impossible so far to obtain a reliable measurement signal,” says the first author of the study, Dr. Steffen Czioska from KIT’s Institute for Chemical Technology and Polymer Chemistry (ITCP). By combining various techniques, the researchers have now succeeded in fundamentally investigating the surface of the iridium oxide catalyst under dynamic operation conditions. For catalysis, researchers from KIT’s ITCP, the Institute of Catalysis Research and Technology, and the Electrochemical Technologies Group of the Institute for Applied Materials combined X-ray absorption spectroscopy for the highly precise investigation of modifications on the atomic level with other analysis methods. Understanding of the processes on the catalyst surface paves the way to further investigation of catalysts at high electric potentials and will contribute to the development of improved and more efficient catalysts meeting the needs of the energy transition, Czioska points out. Green hydrogen is deemed an environmentally compatible chemical energy storage material and, hence, an important element in the decarbonization of e.g. steel and chemical industries.

Source: https://www.sciencedaily.com/releases/2021/08/210824135333.htm

Say Goodbye to the Dots and Dashes: Enhanced Optical Storage Media

Purdue University innovators have created technology aimed at replacing Morse code with coloured “digital characters” to modernize optical storage. They are confident the advancement will help with the explosion of remote data storage during and after the COVID-19 pandemic. Morse code has been around since the 1830s. The familiar dots and dashes system may seem antiquated given the amount of information needed to be acquired, digitally archived and rapidly accessed every day. But those same basic dots and dashes are still used in many optical media to aid in storage. A new technology developed at Purdue is aimed at modernizing the optical digital storage technology. This advancement allows for more data to be stored and for that data to be read at a quicker rate. Rather than using the traditional dots and dashes as commonly used in these technologies, the Purdue innovators encode information in the angular position of tiny antennas, allowing them to store more data per unit area. “The storage capacity greatly increases because it is only defined by the resolution of the sensor by which you can determine the angular positions of antennas,” said Alexander Kildishev, an associate professor of electrical and computer engineering in Purdue’s College of Engineering. “We map the antenna angles into colours, and the colours are decoded.” Technology has aided in increasing storage space availability in optical digital storage technologies. Not all optical data storage media needs to be laser-writable or rewritable. The majority of CDs, DVDs, and Blu-Ray discs are “stamped” and not recordable at all. This class of optical media is an essential part of disposable cold storage with a rapid access rate, long-lasting shelf life, and excellent archival capabilities. The making of a Blu-Ray disc is based on the pressing process, where the silicon stamper replicates the same dot-and-dashes format the final disc is getting. A thin nickel coating is then added to get a negative stamp. The Blu-Rays, as well as DVDs and CDs, are just mass-produced. This new development not only allows for more information to be stored but also increases the readout rate. Future applications for this technology include security tagging and cryptography. To continue developing these capabilities, the team is looking to partner with interested parties in the industry.

Source: https://scitechdaily.com/say-goodbye-to-the-dots-and-dashes-enhanced-optical-storage-media

Sweat-Proof Electronic “Smart Skin” Takes Reliable Vitals, Even During Workouts

The design could lead to conformable wearable monitors to track skin cancer and other conditions. MIT engineers and researchers in South Korea have developed a sweat-proof “electronic skin” — a conformable, sensor-embedded sticky patch that monitors a person’s health without malfunctioning or peeling away, even when a wearer is perspiring. The patch is patterned with artificial sweat ducts, similar to pores in human skin, that the researchers etched through the material’s ultrathin layers. The pores perforate the patch in a kirigami-like pattern, similar to that of the Japanese paper-cutting art. The design ensures that sweat can escape through the patch, preventing skin irritation and damage to embedded sensors. The kirigami design also helps the patch conform to human skin as it stretches and bends. This flexibility, paired with the material’s ability to withstand sweat, enables it to monitor a person’s health over long periods of time, which has not been possible with previous “e-skin” designs. The results are a step toward long-lasting smart skins that may track daily vitals or the progression skin cancer and other conditions. The researchers tested the e-skin by sticking it to a volunteer’s wrist and forehead for a week. The volunteer wore the tape during sweat-inducing activities, such as running on a treadmill for 30 minutes and consuming a spicy meal, pictured. But the team soon came against a barrier that other e-skin designs have yet to clear: sweat. If an e-skin were to work over the long-term, Kim realized it would have to be permeable to not just vapor but also sweat. For design inspiration, the researchers looked to human sweat pores. They found that the diameter of the average pore measures about 100 microns, and that pores are randomly distributed throughout skin. They ran some initial simulations to see how they might overlay and arrange artificial pores, in a way that would not block actual pores in human skin. They started with a periodic pattern of holes, each about the size of an actual sweat pore. They found that if pores were spaced close together, at a distance smaller than an average pore’s diameter, the pattern as a whole would efficiently permeate sweat. But they also found that if this simple hole pattern were etched through a thin film, the film was not very stretchable, and it broke easily when applied to skin. The researchers found they could increase the strength and flexibility of the hole pattern by cutting thin channels between each hole, creating a pattern of repeating dumbbells, rather than simple holes, that relaxed strain, rather than concentrating it in one place. This pattern, when etched into a material, created a stretchable, kirigami-like effect. Following this rationale, the team fabricated an electronic skin from multiple functional layers, each which they etched with dumbbell-patterned pores. The skin’s layers comprise an ultrathin semiconductor-patterned array of sensors to monitor temperature, hydration, ultraviolet exposure, and mechanical strain. This sensor array is sandwiched between two thin protective films, all of which overlays a sticky polymer adhesive. The researchers tested the e-skin by sticking it to a volunteer’s wrist and forehead. The volunteer wore the tape continuously over a week. Throughout this period, the new e-skin reliably measured his temperature, hydration levels, UV exposure, and pulse, even during sweat-inducing activities, such as running on a treadmill for 30 minutes and consuming a spicy meal. The team’s design also conformed to skin, sticking to the volunteer’s forehead as he was asked to frown repeatedly while sweating profusely, compared with other e-skin designs that lacked sweat permeability, and easily detached from the skin.

Source: https://scitechdaily.com/sweat-proof-electronic-smart-skin-takes-reliable-vitals-even-during-workouts/

New Algorithm Trains Drones to Fly Around Obstacles at High Speeds

New algorithm could enable fast, nimble drones for time-critical operations such as search and rescue. If you follow autonomous drone racing, you likely remember the crashes as much as the wins. In drone racing, teams compete to see which vehicle is better trained to fly fastest through an obstacle course. But the faster drones fly, the more unstable they become, and at high speeds their aerodynamics can be too complicated to predict. Crashes, therefore, are a common and often spectacular occurrence. But if they can be pushed to be faster and more nimble, drones could be put to use in time-critical operations beyond the race course, for instance to search for survivors in a natural disaster. Now, aerospace engineers at MIT have devised an algorithm that helps drones find the fastest route around obstacles without crashing. The new algorithm combines simulations of a drone flying through a virtual obstacle course with data from experiments of a real drone flying through the same course in a physical space. The researchers found that a drone trained with their algorithm flew through a simple obstacle course up to 20 percent faster than a drone trained on conventional planning algorithms. Interestingly, the new algorithm didn’t always keep a drone ahead of its competitor throughout the course. In some cases, it chose to slow a drone down to handle a tricky curve, or save its energy in order to speed up and ultimately overtake its rival. Training drones to fly around obstacles is relatively straightforward if they are meant to fly slowly. That’s because aerodynamics such as drag don’t generally come into play at low speeds, and they can be left out of any modeling of a drone’s behavior. But at high speeds, such effects are far more pronounced, and how the vehicles will handle is much harder to predict. To get an understanding for how high-speed aerodynamics affect drones in flight, researchers have to run many experiments in the lab, setting drones at various speeds and trajectories to see which fly fast without crashing — an expensive, and often crash-inducing training process. Instead, the MIT team developed a high-speed flight-planning algorithm that combines simulations and experiments, in a way that minimizes the number of experiments required to identify fast and safe flight paths. The researchers started with a physics-based flight planning model, which they developed to first simulate how a drone is likely to behave while flying through a virtual obstacle course. They simulated thousands of racing scenarios, each with a different flight path and speed pattern. They then charted whether each scenario was feasible (safe), or infeasible (resulting in a crash). From this chart, they could quickly zero in on a handful of the most promising scenarios, or racing trajectories, to try out in the lab. To demonstrate their new approach, the researchers simulated a drone flying through a simple course with five large, square-shaped obstacles arranged in a staggered configuration. They set up this same configuration in a physical training space, and programmed a drone to fly through the course at speeds and trajectories that they previously picked out from their simulations. They also ran the same course with a drone trained on a more conventional algorithm that does not incorporate experiments into its planning. Overall, the drone trained on the new algorithm “won” every race, completing the course in a shorter time than the conventionally trained drone. In some scenarios, the winning drone finished the course 20 percent faster than its competitor, even though it took a trajectory with a slower start, for instance taking a bit more time to bank around a turn. The researchers plan to fly more experiments, at faster speeds, and through more complex environments, to further improve their algorithm.

Source: https://scitechdaily.com/new-algorithm-trains-drones-to-fly-around-obstacles-at-high-speeds

3D Magnetic Nanonetwork Breakthrough Could Enable New Generation of 3D Storage Technologies

Three dimensional (3D) nano-network promise a new era in modern solid state physics with numerous applications in photonics, bio-medicine, and spintronics. The realization of 3D magnetic nano-architectures could enable ultra-fast and low-energy data storage devices. Due to competing magnetic interactions in these systems magnetic charges or magnetic monopoles can emerge, which can be utilized as mobile, binary information carriers. Researchers at University of Vienna have now designed the first 3D artificial spin ice lattice hosting unbound magnetic charges. The results present a first theoretical demonstration that, in the new lattice, the magnetic monopoles are stable at room temperature and can be steered on-demand by external magnetic fields. Emergent magnetic monopoles are observed in a class of magnetic materials called spin ices. However, the atomic scales and required low temperatures for their stability limit their controllability. This led to the development of 2D artificial spin ice, where the single atomic moments are replaced by magnetic nano-islands arranged on different lattices. The up-scaling allowed the study of emergent magnetic monopoles on more accessible platforms. Reversing the magnetic orientation of specific nano-islands propagates the monopoles one vertex further, leaving a trace behind. This trace, Dirac Strings, necessarily stores energy and bind the monopoles, limiting their mobility. Researchers around Sabri Koraltan and Florian Slanovc, and led by Dieter Suess at the University of Vienna, have now designed a first 3D artificial spin ice lattice that combines the advantages of both atomic- and 2D artificial spin ices. In a cooperation with Nanomagnetism and Magnonics group from University of Vienna, and Theoretical Division of Los Alamos Laboratory, USA, the benefits of the new lattice are studied employing micromagnetic simulations. Here, flat 2D nano-islands are replaced by magnetic rotational ellipsoids, and a high symmetry three-dimensional lattice is used. “Due to the degeneracy of the ground state the tension of the Dirac strings vanish unbinding the magnetic monopoles,” remarks Sabri Koraltan, one of the first-authors of the study. The researchers took the study further to the next step, where in their simulations one magnetic monopole was propagated through the lattice by applying external magnetic fields, demonstrating its application as information carriers in a 3D magnetic nano-network. Sabri Koraltan adds “We make use of the third dimension and high symmetry in the new lattice to unbind the magnetic monopoles, and move them in desired directions, almost like true electrons.” The other first-author Florian Slanovc concludes, “The thermal stability of the monopoles around room temperature and above could lay the foundation for groundbreaking new generation of 3D storage technologies.”

Source: https://scitechdaily.com/3d-magnetic-nanonetwork-breakthrough-could-enable-new-generation-of-3d-storage-technologies

Self-Harvesting Energy to Power Rechargeable Devices, Sensors

Self-harvesting energy from indoor environments proves effective for charging batteries. As more of our devices require recharging of their batteries, researchers are looking to ambient lighting as a potential source of generating small amounts of power for indoor devices. Andrew Shore and Behrang Hamadani, from the National Institute of Standards and Technology, present their findings on the capabilities of indoor solar cells in generating power under an LED. The researchers used one lighting source, a white LED with a color coordinate temperature of 3,000 K and an illuminance of 1,000 lux, akin to normal brightness for indoor lights, to test three different modules — a gallium indium phosphide (GaInP) semiconductor, a gallium arsenide (GaAs) semiconductor, and a silicon (Si) semiconductor. The light source peaked in intensity on the shorter wavelengths of light. “Under these light settings, the GaInP mini module performed with the highest power conversion efficiency, followed by the GaAs mini module, with the Si mini module as the lowest performer,” Shore said. “The GaInP and GaAs modules have a better spectral match with this visible-spectrum LED light source.” Since there is usually plenty of indoor ambient light from different sources, a ceiling light in an office environment would be enough to charge any of the mini modules that were tested, making them all viable as power sources for indoor batteries and sensors. Shore said the GaInP would require the least amount of light and still maintain high efficiency, but not all indoor light sources are LEDs. “Different light sources have different spectra,” he said. “For instance, an incandescent light source has a large portion of its irradiance in the near infrared region. Fluorescent lights have several spikes in intensity at different places in the visible spectrum. LED lights generally have one short, prominent peak around 450 nanometers and another more gradual peak around 600 nm. Each of these light sources will affect the power conversion efficiency of the photovoltaic technology.” Shore said the next step will be testing the mini modules under real-world conditions, like a person turning a light on and off at regular intervals. They hope to operate more than one sensor being powered by a module during that testing.

Source: https://scitechdaily.com/self-harvesting-energy-to-power-rechargeable-devices-sensors

Low-Cost, Inflatable Bionic Hand Gives Amputees Real-Time Tactile Control

For the more than 5 million people in the world who have undergone an upper-limb amputation, prosthetics have come a long way. Beyond traditional mannequin-like appendages, there is a growing number of commercial neuroprosthetics — highly articulated bionic limbs, engineered to sense a user’s residual muscle signals and robotically mimic their intended motions. But this high-tech dexterity comes at a price. Neuroprosthetics can cost tens of thousands of dollars and are built around metal skeletons, with electrical motors that can be heavy and rigid. Now engineers at MIT and Shanghai Jiao Tong University have designed a soft, lightweight, and potentially low-cost neuroprosthetic hand. Amputees who tested the artificial limb performed daily activities, such as zipping a suitcase, pouring a carton of juice, and petting a cat, just as well as — and in some cases better than —those with more rigid neuroprosthetics. The researchers found the prosthetic, designed with a system for tactile feedback, restored some primitive sensation in a volunteer’s residual limb. The new design is also surprisingly durable, quickly recovering after being struck with a hammer or run over with a car. The smart hand is soft and elastic, and weighs about half a pound. The team’s artificial hand is made from soft, stretchy material — in this case, the commercial elastomer EcoFlex. The prosthetic comprises five balloon-like fingers, each embedded with segments of fiber, similar to articulated bones in actual fingers. The bendy digits are connected to a 3-D-printed “palm,” shaped like a human hand. Rather than controlling each finger using mounted electrical motors, as most neuroprosthetics do, the researchers used a simple pneumatic system to precisely inflate fingers and bend them in specific positions. This system, including a small pump and valves, can be worn at the waist, significantly reducing the prosthetic’s weight. Lin developed a computer model to relate a finger’s desired position to the corresponding pressure a pump would have to apply to achieve that position. Using this model, the team developed a controller that directs the pneumatic system to inflate the fingers, in positions that mimic five common grasps, including pinching two and three fingers together, making a balled-up fist, and cupping the palm. The pneumatic system receives signals from EMG sensors — electromyography sensors that measure electrical signals generated by motor neurons to control muscles. The sensors are fitted at the prosthetic’s opening, where it attaches to a user’s limb. In this arrangement, the sensors can pick up signals from a residual limb, such as when an amputee imagines making a fist. The team then used an existing algorithm that “decodes” muscle signals and relates them to common grasp types. They used this algorithm to program the controller for their pneumatic system. When an amputee imagines, for instance, holding a wine glass, the sensors pick up the residual muscle signals, which the controller then translates into corresponding pressures. The pump then applies those pressures to inflate each finger and produce the amputee’s intended grasp. Going a step further in their design, the researchers looked to enable tactile feedback — a feature that is not incorporated in most commercial neuroprosthetics. To do this, they stitched to each fingertip a pressure sensor, which when touched or squeezed produces an electrical signal proportional to the sensed pressure. Each sensor is wired to a specific location on an amputee’s residual limb, so the user can “feel” when the prosthetic’s thumb is pressed, for example, versus the forefinger. To test the inflatable hand, the researchers enlisted two volunteers, each with upper-limb amputations. Once outfitted with the neuroprosthetic, the volunteers learned to use it by repeatedly contracting the muscles in their arm while imagining making five common grasps.

Source: https://scitechdaily.com/low-cost-inflatable-bionic-hand-gives-amputees-real-time-tactile-control/