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Researchers develop new technology for isolation of software components with lesser computing power

In the coming future, protection of sensitive information such as passwords, credit card numbers will require less computational work. Scientists at Max Planck Institute for Software Systems in Kaiserslautern and Saarbrücken have developed a new technology known as ERIM for isolating software components from one another. With the help of this, sensitive data can be protected from hackers when it is processed in online transactions. This technique has nearly three to five times less computational overhead than the last isolation technology. As a result, it is more suitable for use in online transactions. For this, the researchers were awarded the Internet Defense Prize 2019 by USENIX and Facebook. 

Different types of security technologies such as firewalls help in protecting the computer programs from malicious softwares. Even a small security lapse can lead to hackers accessing the components of a software. It can also go as far as hackers accessing the financial details of the users’ accounts and making credit card transactions with them. As an example, the Heartbleed bug in the OpenSSL encryption software made the usernames and passwords of different online services vulnerable to hackers.

For preventing these attacks, developers can isolate different software components similar to the walls of a fortress preventing access to its central area even if attackers manage to overcome the external obstacles. The current isolation methods often require upto 30 percent more CPU power and many servers running simultaneously which increase the infrastructure costs. Deepak Garg, a leading researcher at Max Planck Institute said that many services do not believe in the justification of the greater costs and hence do not use the isolation methods. He added that their isolation technique uses only five percent more time for computation which makes it attractive to the companies. This is the reason they have been awarded the lucrative 100,000 USD prize by USENIX and Facebook. 

A team led by Deepak Garg and Peter Druschel, director at Max Planck Institute for Software Systems combined a hardware feature which was introduced by Intel in their microprocessors with software for building the isolation method. The new hardware feature is known as MPK or Memory Protection Keys. 

MPK on its own cannot isolate the components as it can still be exploited by clever attackers. MPK was used with another method known as instruction rewriting. Peter Druschel said that the code of a software can be written in such a manner that an attacker cannot exploit the “walls” of the components. This is done keeping the purpose of the software intact. Both these methods can be used to divide the memory of software with very less computational work thus isolating the parts from one another. Remaining isolation technologies access the kernel of the operating system for this purpose thereby using more computational effort. With increase in the pace of software development, the practicality of data protection has to be maintained. This often involves unconventional approaches. 

Researchers have finally created a quantum X-Ray device

Researchers have finally created a quantum X-Ray device

A research team has demonstrated quantum enhancement in a real X-ray machine, thereby achieving the goal of elimination of background noise for precision detection. The relationship between photon pairs on quantum scales can be used to generate sharp, high-resolution images compared to classical optics. This field is called quantum imaging and has huge potential since optical light can be used to show objects that cannot be seen normally like bones and organs. Quantum correlation describes several relationships between photon pairs, among which entanglement is one and it is used in optical quantum imaging.

The technical challenges of generating entangled photons in X-ray wavelength are greater than optical light, so the team used a different approach. They used a method called quantum illumination to minimize background noise. Using parametric down-conversion (PDC), the researchers split a high energy photon into two low energy photons, signal photon, and idler photon. Researchers mentioned that the application of X-Ray PDC as a source of ghost imaging has been demonstrated recently.  In previous publications, the photon statistics were not measured with any experimental evidence to date, which is generated by X-Ray PDC. Similarly, the observations of quantum enhancement sensitivity were not reported at X-ray wavelengths. The work appears in Physical Review X.

The X-Ray PDC was achieved with the help of a diamond crystal. The non-linear structure of crystal splits X-Ray photons into signal and idler beams, each having half the energy of the pump beam. The team scaled up power by using SPring-8 synchrotron in Japan. They shot a 22 KeV beam of X-rays at their crystal, splitting into two beams, carrying the energy of 11 KeV. The signal beam is sent towards the object which has to be imaged. Here, it is a small metal piece with three slits and a detector on the other side. The idler beam is directly sent to another detector so that each beam hits its respective detector at the same place and time.

The researchers then compared the detections. They found 100 correlated photons per point in the image and 10,000 background photons. Researchers could match each idler to the signal and could trace back the photons which came from the beam, thereby eliminating the noise. They later compared the images to the images developed using non-correlated photons. The correlated photons produced a sharper image.

Quantum X-ray imaging could have many uses outside current X-ray technology with a benefit of lower X-ray radiation required for imaging. This means that samples which are easily damaged by X-Rays could be imaged along with the samples with lower temperature requirement. As quantum X-Ray requires particle accelerator, there are no medical applications currently. The researchers say that they have demonstrated the ability to utilize the strong time-energy correlations of photon pairs for quantum-enhanced photodetection. The procedure they have presented possesses great potential for improving the performances of X-ray measurements.

Journal Reference: Physical Review X.

Majority of social media users are happy for their data to be used for research, study reveals

Majority of social media users are happy for their data to be used for research, study reveals

Social media users are generally positive about their personal data being used for research purposes, a study by the University of York has revealed.

Social media platforms have often been used by researchers to gather data on so-called “adverse events” from drugs and medical procedures, with adverse events often being under-reported in studies.

Social media users cited the potential benefit for medical research as the most influential factor for them to consent to their data being used for research.

Concerns

However, the study revealed concerns around regulation and the ethics of using personal data for research purposes.

The qualitative study used interviews, virtual discussions and focus groups to explore views and attitudes towards the use of social media to monitor adverse events.

Some of those taking part had suffered adverse reactions to medicines themselves.

Safety

Lead author Dr Su Golder, NIHR Postdoctoral Research Fellow from the University of York’s Department of Health Sciences said: “We found it interesting that social media users were happy for their data to be used for research, but as researchers it’s important to take into account their concerns and make sure we assure people that their data will be used appropriately and safely.

“It is clear that social media users are in favour of some sort of overarching guidance for all institutions to follow and that further work is required to establish when consent is required for individual’s social media data to be used.”

Dr Golder said researchers were already aware of the huge potential benefits of using social media for research purposes.

Helping researchers

“It could be argued that some health scandals of the past could have been averted or discovered earlier if social media was around then as the adverse effects would probably have been highlighted,” she added.

“Social media has a part to play in helping researchers and our study has revealed that people are willing for it to be used under the right circumstances.

“Our findings will not only help direct future research but will also provide people managing social media websites, universities, ethics boards, pharma companies and policymakers with evidence to inform policy and guidance on the use of social media data for research. “

Robotic thread is designed to slip through the brain’s blood vessels

Robotic thread is designed to slip through the brain’s blood vessels

MIT engineers have developed a magnetically steerable, thread-like robot that can actively glide through narrow, winding pathways, such as the labrynthine vasculature of the brain.

In the future, this robotic thread may be paired with existing endovascular technologies, enabling doctors to remotely guide the robot through a patient’s brain vessels to quickly treat blockages and lesions, such as those that occur in aneurysms and stroke.

“Stroke is the number five cause of death and a leading cause of disability in the United States. If acute stroke can be treated within the first 90 minutes or so, patients’ survival rates could increase significantly,” says Xuanhe Zhao, associate professor of mechanical engineering and of civil and environmental engineering at MIT. “If we could design a device to reverse blood vessel blockage within this ‘golden hour,’ we could potentially avoid permanent brain damage. That’s our hope.”

Zhao and his team, including lead author Yoonho Kim, a graduate student in MIT’s Department of Mechanical Engineering, describe their soft robotic design today in the journal Science Robotics. The paper’s other co-authors are MIT graduate student German Alberto Parada and visiting student Shengduo Liu.

In a tight spot

To clear blood clots in the brain, doctors often perform an endovascular procedure, a minimally invasive surgery in which a surgeon inserts a thin wire through a patient’s main artery, usually in the leg or groin. Guided by a fluoroscope that simultaneously images the blood vessels using X-rays, the surgeon then manually rotates the wire up into the damaged brain vessel. A catheter can then be threaded up along the wire to deliver drugs or clot-retrieval devices to the affected region.

Kim says the procedure can be physically taxing, requiring surgeons, who must be specifically trained in the task, to endure repeated radiation exposure from fluoroscopy.

“It’s a demanding skill, and there are simply not enough surgeons for the patients, especially in suburban or rural areas,” Kim says.

The medical guidewires used in such procedures are passive, meaning they must be manipulated manually, and are typically made from a core of metallic alloys, coated in polymer, a material that Kim says could potentially generate friction and damage vessel linings if the wire were to get temporarily stuck in a particularly tight space.

The team realized that developments in their lab could help improve such endovascular procedures, both in the design of the guidewire and in reducing doctors’ exposure to any associated radiation.

Threading a needle

Over the past few years, the team has built up expertise in both hydrogels — biocompatible materials made mostly of water — and 3-D-printed magnetically-actuated materials that can be designed to crawl, jump, and even catch a ball, simply by following the direction of a magnet.

In this new paper, the researchers combined their work in hydrogels and in magnetic actuation, to produce a magnetically steerable, hydrogel-coated robotic thread, or guidewire, which they were able to make thin enough to magnetically guide through a life-size silicone replica of the brain’s blood vessels.

The core of the robotic thread is made from nickel-titanium alloy, or “nitinol,” a material that is both bendy and springy. Unlike a clothes hanger, which would retain its shape when bent, a nitinol wire would return to its original shape, giving it more flexibility in winding through tight, tortuous vessels. The team coated the wire’s core in a rubbery paste, or ink, which they embedded throughout with magnetic particles.

Finally, they used a chemical process they developed previously, to coat and bond the magnetic covering with hydrogel — a material that does not affect the responsiveness of the underlying magnetic particles and yet provides the wire with a smooth, friction-free, biocompatible surface.

They demonstrated the robotic thread’s precision and activation by using a large magnet, much like the strings of a marionette, to steer the thread through an obstacle course of small rings, reminiscent of a thread working its way through the eye of a needle.

The researchers also tested the thread in a life-size silicone replica of the brain’s major blood vessels, including clots and aneurysms, modeled after the CT scans of an actual patient’s brain. The team filled the silicone vessels with a liquid simulating the viscosity of blood, then manually manipulated a large magnet around the model to steer the robot through the vessels’ winding, narrow paths.

Kim says the robotic thread can be functionalized, meaning that features can be added — for example, to deliver clot-reducing drugs or break up blockages with laser light. To demonstrate the latter, the team replaced the thread’s nitinol core with an optical fiber and found that they could magnetically steer the robot and activate the laser once the robot reached a target region.

When the researchers ran comparisons between the robotic thread coated versus uncoated with hydrogel, they found that the hydrogel gave the thread a much-needed, slippery advantage, allowing it to glide through tighter spaces without getting stuck. In an endovascular surgery, this property would be key to preventing friction and injury to vessel linings as the thread works its way through.

“One of the challenges in surgery has been to be able to navigate through complicated blood vessels in the brain, which has a very small diameter, where commercial catheters can’t reach,” says Kyujin Cho, professor of mechanical engineering at Seoul National University. “This research has shown potential to overcome this challenge and enable surgical procedures in the brain without open surgery.”

And just how can this new robotic thread keep surgeons radiation-free? Kim says that a magnetically steerable guidewire does away with the necessity for surgeons to physically push a wire through a patient’s blood vessels. This means that doctors also wouldn’t have to be in close proximity to a patient, and more importantly, the radiation-generating fluoroscope.

In the near future, he envisions endovascular surgeries that incorporate existing magnetic technologies, such as pairs of large magnets, the directions of which doctors can manipulate from just outside the operating room, away from the fluoroscope imaging the patient’s brain, or even in an entirely different location.

“Existing platforms could apply magnetic field and do the fluoroscopy procedure at the same time to the patient, and the doctor could be in the other room, or even in a different city, controlling the magnetic field with a joystick,” Kim says. “Our hope is to leverage existing technologies to test our robotic thread in vivo in the next step.”

Materials provided by Massachusetts Institute of Technology

Brain Synapse

Researchers develop device which can forget things like our brain

Scientists are trying to emulate the human brain since it is the ultimate computing machine. In this effort, the latest research has resulted in the development of a device which can also “forget” memories much like our brains. 

It is known as a second-order memristor. It mimics the synapse of a human brain in such a manner where it stores information but then loses it slowly when it is not accessed for a long time period. The device currently does not have a practical use but this could be a stepping stone to a unique kind of neurocomputer which can perform the same functions that a human brain does. The work appears in ACS Applied Materials and Interfaces

In an analogue neurocomputer, neurons and synapses can be replicated by the on-chip electronic components. This could help in amplifying computational speeds as well as decreasing the energy requirements of the computer. 

Presently the analogue neurocomputers are not feasible as researchers need to figure out how synaptic plasticity can be also implemented in electronics. This is the technique in which the active brain synapses become strong while the inactive ones get weak resulting in fading away of memories. 

Previously, memristors were produced by nanosized conductive bridges which decayed with the passing of time similar to how we forget some incidents. 

Anastasia Chouprik, a physicist from the Moscow Institute of Physics and Technology(MIPT), Russia said that in the first order memristor, the problem is that the device changes its behaviour with the passage of time resulting in its breakdown. The synaptic plasticity has been implemented in a robust manner this time which sustained the change in the state of the system for 100 billion times. 

A ferroelectric material, hafnium oxide was used along with electric polarisation which changes in response to an electric field. It is already used by Intel for manufacturing microchips. So it would be easier to introduce the memristors.

Researchers faced challenges in finding the proper thickness for the ferroelectric material. They found four nanometres to be the ideal thickness as a nanometre more or less would make it unsuitable for application. 

The forgetfulness is implemented through an imperfection as a result of which microprocessors based on hafnium are difficult to develop. The imperfection is the defect present at the interface between hafnium oxide and silicon which results in the decrease in the memristor conductivity. 

There is a long way to go as these memory cells have to be made more reliable and suitable enough to be integrated into flexible electronics. Another physicist, Vitalii Mikheev said that they would be studying the relation between several mechanisms through changing the memristor. There might be mechanisms other than ferroelectric effect which have to be studied.

Journal Reference: ACS Applied Materials and Interfaces

Google reveals security flaws in iOS resulted hacking of users personal data

“Security flaws in ios lead to hacking of users personal data”, says Google

Google security researchers said that they have detected several malicious websites which when visited would hack into the iPhone of the visitor without any alert. This is possible by the exploitation of a number of security flaws in the software which were previously not disclosed. 

Google’s Project Zero said that these harmful websites were visited several thousands of times per week by visitors who had no idea of what was going on. Ian Beer, Project Zero’s security researcher said that for the device to be exploited it was enough to visit the malicious website which would then install a monitoring implant if it was successful. The hacking of the iPhones continued for a minimum period of two years.  

Five unique exploit chains were detected that involved a total of twelve separate security flaws. Seven of these flaws involved Safari which is the default browser on iPhones. An attacker managed to get root access( the highest access level) to the iPhone with the help of the other five exploit chains. As a result, all the features could be accessed by the attackers including those which were not accessed even by the users. This helped them in installing applications or other malware in their devices with no knowledge of the users. 

According to an analysis of Google, the personal photos, messages of the users along with their live location could be stolen due to these vulnerabilities. It would also provide access to the saved passwords in the devices. iOS versions 10 to 12 were affected by these vulnerabilities.

They were privately disclosed by Google to Apple in the month of February where it was provided only a week for fixing the flaws and roll out the updates to the users. Since the security flaws were of such a severe nature, very less time period was provided to the developers. After six days, Apple rolled out security patches for iOS 12.1.4 for iPhone 5s, iPad Air and other later models. 

Beer said that it might be possible there are other hacking campaigns which are currently operating. Apple has a good reputation in handling security-related issues. It also increased the bug bounty payment to a maximum of a million dollars if security researchers can detect the flaws which allow the intruders to get root-level access to the device without any interaction from the user side. Under Apple’s new bounty rules — set to go into effect later this year — Google would’ve been eligible for several million dollars in bounties. 

RFID Chip

Researchers develop stickers similar to skin for monitoring health

Some health devices are on the edge of merging smoothly with our skin as wearable technology grows ever tinier and more sensitive. A flexible digital sticker has been developed by the Researchers at Stanford University that can track a person’s pulse, respiration and muscle activity simultaneously. The work appears in the Nature Electronics journal. 

Bodynet which is the explanation of the working of this novel device asserts that the delicate and lightweight sensors fuse easily with the skin, stretching and bending gradually with each motion, heartbeat or breath. These accurate wireless measurements are then transported from the sticker to a close-by flexible receiver which is cropped somewhere onto a person’s clothing. The device has only been experimented on one individual so far and the receiver of this device is still a bit clumsy and requires further development.

The researchers have planned to improve their model even after 3 years of work in the near future. They expect the device to be used for tracking sleep disorders and heart conditions in real-time by the physicians.

The chemical engineer Zhenan Bao said that they think that in the future they can develop a full-body skin-sensor array device that can assemble physiological information without intervening with a person’s normal behavior.

There is a long way to go, researchers are moving rapidly on wearable technologies. Recently, researchers worldwide have been building new methods to hold medical devices onto the skin or implant medical sensors in the tattoo ink. Recent reports on wearable devices predict that as the industry prospers, the market could rise from US$8.9 billion in 2018 to US$29.9 billion by 2023.

The new design from Stanford uses a magnificent new wireless system including an antenna made from metallic ink, screen-printed onto a rubber sticker that can bend and stretch like human skin, unlike the sensors that stick on the skin. The electric current flowing through this metallic ink is varied as it goes through the motions giving precise measurements of a person’s physicality. The very close contact motion with the skin in the flexible antennae can disturb the radio waves sent to the receiver.

The team of researchers had to develop a novel type of wireless communication based on radiofrequency identification (RFID) that would enable the antennae to transmit strong and reliable signals to the receiver without being stretched and contracted to fix this issue. The key-card generates an access code when placed near a receiver and then sends back to the receiver for access allowing for the battery-free key card to steal a little of the reader’s energy.

The authors concluded that in spite of the system with Bodynet stickers becoming insensitive to strain-induced antenna disruptions, it can still maintain full functionality even when subjected to 50 % strain. Moreover, they added that the device can potentially be used for real-time physiological and clinical findings in a modern personal health monitoring system by continuously analyzing critical human signals (pulse, respiration and body movement).

The researchers are planning to integrate sweat, temperature and other sensors into their sticker and also reducing the receiver’s size so it can one day be woven into clothing.

Journal Reference: Nature Electronics journal. 

MIT engineers build advanced microprocessor out of carbon nanotubes

MIT engineers build advanced microprocessor out of carbon nanotubes

After years of tackling numerous design and manufacturing challenges, MIT researchers have built a modern microprocessor from carbon nanotube transistors, which are widely seen as a faster, greener alternative to their traditional silicon counterparts.

The microprocessor, described today in the journal Nature, can be built using traditional silicon-chip fabrication processes, representing a major step toward making carbon nanotube microprocessors more practical.

Silicon transistors — critical microprocessor components that switch between 1 and 0 bits to carry out computations — have carried the computer industry for decades. As predicted by Moore’s Law, industry has been able to shrink down and cram more transistors onto chips every couple of years to help carry out increasingly complex computations. But experts now foresee a time when silicon transistors will stop shrinking, and become increasingly inefficient.

Making carbon nanotube field-effect transistors (CNFET) has become a major goal for building next-generation computers. Research indicates CNFETs have properties that promise around 10 times the energy efficiency and far greater speeds compared to silicon. But when fabricated at scale, the transistors often come with many defects that affect performance, so they remain impractical.

The MIT researchers have invented new techniques to dramatically limit defects and enable full functional control in fabricating CNFETs, using processes in traditional silicon chip foundries. They demonstrated a 16-bit microprocessor with more than 14,000 CNFETs that performs the same tasks as commercial microprocessors. The Nature paper describes the microprocessor design and includes more than 70 pages detailing the manufacturing methodology.

The microprocessor is based on the RISC-V open-source chip architecture that has a set of instructions that a microprocessor can execute. The researchers’ microprocessor was able to execute the full set of instructions accurately. It also executed a modified version of the classic “Hello, World!” program, printing out, “Hello, World! I am RV16XNano, made from CNTs.”

“This is by far the most advanced chip made from any emerging nanotechnology that is promising for high-performance and energy-efficient computing,” says co-author Max M. Shulaker, the Emanuel E Landsman Career Development Assistant Professor of Electrical Engineering and Computer Science (EECS) and a member of the Microsystems Technology Laboratories. “There are limits to silicon. If we want to continue to have gains in computing, carbon nanotubes represent one of the most promising ways to overcome those limits. [The paper] completely re-invents how we build chips with carbon nanotubes.”

Joining Shulaker on the paper are: first author and postdoc Gage Hills, graduate students Christian Lau, Andrew Wright, Mindy D. Bishop, Tathagata Srimani, Pritpal Kanhaiya, Rebecca Ho, and Aya Amer, all of EECS; Arvind, the Johnson Professor of Computer Science and Engineering and a researcher in the Computer Science and Artificial Intelligence Laboratory; Anantha Chandrakasan, the dean of the School of Engineering and the Vannevar Bush Professor of Electrical Engineering and Computer Science; and Samuel Fuller, Yosi Stein, and Denis Murphy, all of Analog Devices.

Fighting the “bane” of CNFETs

The microprocessor builds on a previous iteration designed by Shulaker and other researchers six years ago that had only 178 CNFETs and ran on a single bit of data. Since then, Shulaker and his MIT colleagues have tackled three specific challenges in producing the devices: material defects, manufacturing defects, and functional issues. Hills did the bulk of the microprocessor design, while Lau handled most of the manufacturing.

For years, the defects intrinsic to carbon nanotubes have been a “bane of the field,” Shulaker says. Ideally, CNFETs need semiconducting properties to switch their conductivity on an off, corresponding to the bits 1 and 0. But unavoidably, a small portion of carbon nanotubes will be metallic, and will slow or stop the transistor from switching. To be robust to those failures, advanced circuits will need carbon nanotubes at around 99.999999 percent purity, which is virtually impossible to produce today.

The researchers came up with a technique called DREAM (an acronym for “designing resiliency against metallic CNTs”), which positions metallic CNFETs in a way that they won’t disrupt computing. In doing so, they relaxed that stringent purity requirement by around four orders of magnitude — or 10,000 times — meaning they only need carbon nanotubes at about 99.99 percent purity, which is currently possible.

Designing circuits basically requires a library of different logic gates attached to transistors that can be combined to, say, create adders and multipliers — like combining letters in the alphabet to create words. The researchers realized that the metallic carbon nanotubes impacted different pairings of these gates differently. A single metallic carbon nanotube in gate A, for instance, may break the connection between A and B. But several metallic carbon nanotubes in gates B may not impact any of its connections.

In chip design, there are many ways to implement code onto a circuit. The researchers ran simulations to find all the different gate combinations that would be robust and wouldn’t be robust to any metallic carbon nanotubes. They then customized a chip-design program to automatically learn the combinations least likely to be affected by metallic carbon nanotubes. When designing a new chip, the program will only utilize the robust combinations and ignore the vulnerable combinations.

“The ‘DREAM’ pun is very much intended, because it’s the dream solution,” Shulaker says. “This allows us to buy carbon nanotubes off the shelf, drop them onto a wafer, and just build our circuit like normal, without doing anything else special.”

Exfoliating and tuning

CNFET fabrication starts with depositing carbon nanotubes in a solution onto a wafer with predesigned transistor architectures. However, some carbon nanotubes inevitably stick randomly together to form big bundles — like strands of spaghetti formed into little balls — that form big particle contamination on the chip.

To cleanse that contamination, the researchers created RINSE (for “removal of incubated nanotubes through selective exfoliation”). The wafer gets pretreated with an agent that promotes carbon nanotube adhesion. Then, the wafer is coated with a certain polymer and dipped in a special solvent. That washes away the polymer, which only carries away the big bundles, while the single carbon nanotubes remain stuck to the wafer. The technique leads to about a 250-times reduction in particle density on the chip compared to similar methods.

Lastly, the researchers tackled common functional issues with CNFETs. Binary computing requires two types of transistors: “N” types, which turn on with a 1 bit and off with a 0 bit, and “P” types, which do the opposite. Traditionally, making the two types out of carbon nanotubes has been challenging, often yielding transistors that vary in performance. For this solution, the researchers developed a technique called MIXED (for “metal interface engineering crossed with electrostatic doping”), which precisely tunes transistors for function and optimization.

In this technique, they attach certain metals to each transistor — platinum or titanium — which allows them to fix that transistor as P or N. Then, they coat the CNFETs in an oxide compound through atomic-layer deposition, which allows them to tune the transistors’ characteristics for specific applications. Servers, for instance, often require transistors that act very fast but use up energy and power. Wearables and medical implants, on the other hand, may use slower, low-power transistors.

The main goal is to get the chips out into the real world. To that end, the researchers have now started implementing their manufacturing techniques into a silicon chip foundry through a program by Defense Advanced Research Projects Agency, which supported the research. Although no one can say when chips made entirely from carbon nanotubes will hit the shelves, Shulaker says it could be fewer than five years. “We think it’s no longer a question of if, but when,” he says.

After years of tackling numerous design and manufacturing challenges, MIT researchers have built a modern microprocessor from carbon nanotube transistors, which are widely seen as a faster, greener alternative to their traditional silicon counterparts.

The microprocessor, described today in the journal Nature, can be built using traditional silicon-chip fabrication processes, representing a major step toward making carbon nanotube microprocessors more practical.

Silicon transistors — critical microprocessor components that switch between 1 and 0 bits to carry out computations — have carried the computer industry for decades. As predicted by Moore’s Law, industry has been able to shrink down and cram more transistors onto chips every couple of years to help carry out increasingly complex computations. But experts now foresee a time when silicon transistors will stop shrinking, and become increasingly inefficient.

Making carbon nanotube field-effect transistors (CNFET) has become a major goal for building next-generation computers. Research indicates CNFETs have properties that promise around 10 times the energy efficiency and far greater speeds compared to silicon. But when fabricated at scale, the transistors often come with many defects that affect performance, so they remain impractical.

The MIT researchers have invented new techniques to dramatically limit defects and enable full functional control in fabricating CNFETs, using processes in traditional silicon chip foundries. They demonstrated a 16-bit microprocessor with more than 14,000 CNFETs that performs the same tasks as commercial microprocessors. The Nature paper describes the microprocessor design and includes more than 70 pages detailing the manufacturing methodology.

The microprocessor is based on the RISC-V open-source chip architecture that has a set of instructions that a microprocessor can execute. The researchers’ microprocessor was able to execute the full set of instructions accurately. It also executed a modified version of the classic “Hello, World!” program, printing out, “Hello, World! I am RV16XNano, made from CNTs.”

“This is by far the most advanced chip made from any emerging nanotechnology that is promising for high-performance and energy-efficient computing,” says co-author Max M. Shulaker, the Emanuel E Landsman Career Development Assistant Professor of Electrical Engineering and Computer Science (EECS) and a member of the Microsystems Technology Laboratories. “There are limits to silicon. If we want to continue to have gains in computing, carbon nanotubes represent one of the most promising ways to overcome those limits. [The paper] completely re-invents how we build chips with carbon nanotubes.”

Joining Shulaker on the paper are: first author and postdoc Gage Hills, graduate students Christian Lau, Andrew Wright, Mindy D. Bishop, Tathagata Srimani, Pritpal Kanhaiya, Rebecca Ho, and Aya Amer, all of EECS; Arvind, the Johnson Professor of Computer Science and Engineering and a researcher in the Computer Science and Artificial Intelligence Laboratory; Anantha Chandrakasan, the dean of the School of Engineering and the Vannevar Bush Professor of Electrical Engineering and Computer Science; and Samuel Fuller, Yosi Stein, and Denis Murphy, all of Analog Devices.

Fighting the “bane” of CNFETs

The microprocessor builds on a previous iteration designed by Shulaker and other researchers six years ago that had only 178 CNFETs and ran on a single bit of data. Since then, Shulaker and his MIT colleagues have tackled three specific challenges in producing the devices: material defects, manufacturing defects, and functional issues. Hills did the bulk of the microprocessor design, while Lau handled most of the manufacturing.

For years, the defects intrinsic to carbon nanotubes have been a “bane of the field,” Shulaker says. Ideally, CNFETs need semiconducting properties to switch their conductivity on an off, corresponding to the bits 1 and 0. But unavoidably, a small portion of carbon nanotubes will be metallic, and will slow or stop the transistor from switching. To be robust to those failures, advanced circuits will need carbon nanotubes at around 99.999999 percent purity, which is virtually impossible to produce today.

The researchers came up with a technique called DREAM (an acronym for “designing resiliency against metallic CNTs”), which positions metallic CNFETs in a way that they won’t disrupt computing. In doing so, they relaxed that stringent purity requirement by around four orders of magnitude — or 10,000 times — meaning they only need carbon nanotubes at about 99.99 percent purity, which is currently possible.

Designing circuits basically requires a library of different logic gates attached to transistors that can be combined to, say, create adders and multipliers — like combining letters in the alphabet to create words. The researchers realized that the metallic carbon nanotubes impacted different pairings of these gates differently. A single metallic carbon nanotube in gate A, for instance, may break the connection between A and B. But several metallic carbon nanotubes in gates B may not impact any of its connections.

In chip design, there are many ways to implement code onto a circuit. The researchers ran simulations to find all the different gate combinations that would be robust and wouldn’t be robust to any metallic carbon nanotubes. They then customized a chip-design program to automatically learn the combinations least likely to be affected by metallic carbon nanotubes. When designing a new chip, the program will only utilize the robust combinations and ignore the vulnerable combinations.

“The ‘DREAM’ pun is very much intended, because it’s the dream solution,” Shulaker says. “This allows us to buy carbon nanotubes off the shelf, drop them onto a wafer, and just build our circuit like normal, without doing anything else special.”

Exfoliating and tuning

CNFET fabrication starts with depositing carbon nanotubes in a solution onto a wafer with predesigned transistor architectures. However, some carbon nanotubes inevitably stick randomly together to form big bundles — like strands of spaghetti formed into little balls — that form big particle contamination on the chip.

To cleanse that contamination, the researchers created RINSE (for “removal of incubated nanotubes through selective exfoliation”). The wafer gets pretreated with an agent that promotes carbon nanotube adhesion. Then, the wafer is coated with a certain polymer and dipped in a special solvent. That washes away the polymer, which only carries away the big bundles, while the single carbon nanotubes remain stuck to the wafer. The technique leads to about a 250-times reduction in particle density on the chip compared to similar methods.

Lastly, the researchers tackled common functional issues with CNFETs. Binary computing requires two types of transistors: “N” types, which turn on with a 1 bit and off with a 0 bit, and “P” types, which do the opposite. Traditionally, making the two types out of carbon nanotubes has been challenging, often yielding transistors that vary in performance. For this solution, the researchers developed a technique called MIXED (for “metal interface engineering crossed with electrostatic doping”), which precisely tunes transistors for function and optimization.

In this technique, they attach certain metals to each transistor — platinum or titanium — which allows them to fix that transistor as P or N. Then, they coat the CNFETs in an oxide compound through atomic-layer deposition, which allows them to tune the transistors’ characteristics for specific applications. Servers, for instance, often require transistors that act very fast but use up energy and power. Wearables and medical implants, on the other hand, may use slower, low-power transistors.

The main goal is to get the chips out into the real world. To that end, the researchers have now started implementing their manufacturing techniques into a silicon chip foundry through a program by Defense Advanced Research Projects Agency, which supported the research. Although no one can say when chips made entirely from carbon nanotubes will hit the shelves, Shulaker says it could be fewer than five years. “We think it’s no longer a question of if, but when,” he says.

Materials provided by Massachusetts Institute of Technology

Boeing X 37B

Spaceplane of US Air Force spends the longest time in orbit around Earth

The Boeing X-37B of US Air Force is a spaceplane which broke the record for the most amount of time in the orbit around Earth but it is unknown when the uncrewed plane is expected to land or what is it doing there because of the classified details about the X-37B mission.

The fifth mission of the X-37B, named the (OTV-5) Orbital Test Vehicle will have spent 719 days in the orbit, 11 days less than completing 2 years around the Earth. The previous record was for 717 days, 20 hours and 42 minutes which was achieved by OTV-4 a few years before.

The Air Force describes X-37B Orbital test Vehicle (OTV) as an experimental test program for demonstration of technologies which are suitable and reusable for the unmanned space platform for US Air Force. There are two main objectives of X-37B. The first is the reusable space technologies and the second consists of performing experiments that can be returned and examined back on Earth.

Upon receiving the commands, the OTV re-enters the atmosphere autonomously and lands on the runway. This is the first vehicle since the NASA Shuttle Orbiter to return back to Earth for inspection and analysis of the experiments however it can stay much longer in space, more than 270 days to be precise. Technologies which are currently tested are thermal protection systems, developed forms of guidance, reentry and landing, navigation and control, avionics, high-temperature structures and seals, reusable insulation, lightweight electromechanical flight systems, hi-tech propulsion systems, advanced materials and autonomous orbital flight.

It looks similar to space shuttles which were highly exciting during the 80s and 90s, but unfortunately, the space shuttle program has been abandoned, with the vehicles being placed in the museums.

The X-37B has completed 4 missions including the usage of Atlas 5 rocket however the most recent mission has been the launch of the SpaceX Falcon 9 rocket on September 7, 2017. Currently, no one knows what is going on in the experiments or what is the end goal and with things like a rise in fascism and disastrous Amazon fires and the way humans are destroying our own planet there is hope that the Air Force is developing some kind of human escape plan. Even the tardigrades have become a multiplanetary species so we can hope humans can achieve something similar. Every launch of the X-37B has taken place at Cape Canaveral in Florida, though some have landed at Vandenberg Air Force Base in California.

Researchers develop practical method for measuring quantum entanglement

Scientists come up with practical method for measurement of quantum entanglement

A team of scientists from Rochester Institute of Technology have created a new method for measuring the quantum entanglement (physical phenomenon that occurs when pairs or groups of particles are generated, interact, or share spatial proximity) that has significant consequences for building the future generation of technology in fields such as computer science, impersonation, safe communication and other areas. The new method for measuring entanglement(complexity) has been summarised by the scientists in a recently published article by Nature Communications journal.

An extraordinary interrelationship was observed in the measurements when two quantum particles like photons, electrons or atom become entangled even if the particles were apart from each other by a large distance. This special quality which can only be described by Quantum Mechanics is the backbone of the various technologies.

Gregory Howland, Assistant Professor and a member of Future Photon Initiative of Rochester Institute of Technology said that Quantum entanglement is a useful resource for performing important activities like quantum computing or secure communication. Also, he said that two people who possess entangled quantum particles can produce an unbreakable key to send messages back and forth to one another in such a way that in case if any third person or party intercepts the message, it will not be possible for them to decipher or decode the message according to laws of physics.

End-user needs to estimate the amount of quantum entanglement present within a given system as quantum technologies have become more sophisticated and complex with every passing day. The new method involving spatially entangled photon pairs needs million-times lesser measurements than the previous methods.

The measurement method has the additional advantage of never over-estimating the amount of entanglement which is present in a system as this method is based on the information theory which studies some of the key factors related to information such as quantification, storage and communication. It has been very crucial for milestone achievements such as compact disc invention, creation of the Internet, Voyager missions.

Howland said that this turns out to be vital because it is not that we are told that we have more of the resource then we actually have and this factor is mainly important for stuff like secure communication to avoid any unwanted interception of a message.

Journal Reference: Nature Communications journal