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In late 2020, Huawei was fighting for its survival as a mobile phone maker.
A few months earlier, the Trump administration had hit the Chinese company with crippling sanctions, cutting it off from global semiconductor supply chains.
The sanctions prevented anyone without a permit from making the chips Huawei designed, and the company was struggling to procure new chips to launch more advanced handsets.
Enlarge (credit: Getty Images)
In the stretch of a few days, two municipal water facilities that serve more than 2 million residents in parts of Pennsylvania and Texas have reported network security breaches that have hamstrung parts of their business or operational processes.
In response to one of the attacks, the Municipal Water Authority of Aliquippa in western Pennsylvania temporarily shut down a pump providing drinking water from the facility’s treatment plant to the townships of Raccoon and Potter, according to reporting by the Beaver Countian. A photo the Water Authority provided to news outlets showed the front panel of a programmable logic controller—a toaster-sized box often abbreviated as PLC that’s used to automate physical processes inside of industrial settings—that displayed an anti-Israeli message. The PLC bore the logo of the manufacturer Unitronics. A sign above it read “Primary PLC.”
The Cybersecurity and Infrastructure Security Administration on Tuesday published an advisory that warned of recent attacks compromising Unitronics PLCs used in Water and Wastewater Systems, which are often abbreviated as WWSes. Although the notice didn’t identify any facilities by name, the account of one hack was almost identical to the one that occurred inside the Aliquippa facility.
Enlarge / Example images generated using Stable Diffusion XL Turbo. (credit: Stable Diffusion XL Turbo / Benj Edwards)
On Tuesday, Stability AI launched Stable Diffusion XL Turbo, an AI image-synthesis model that can rapidly generate imagery based on a written prompt. So rapidly, in fact, that the company is billing it as "real-time" image generation, since it can also quickly transform images from a source, such as a webcam, quickly.
SDXL Turbo's primary innovation lies in its ability to produce image outputs in a single step, a significant reduction from the 20–50 steps required by its predecessor. Stability attributes this leap in efficiency to a technique it calls Adversarial Diffusion Distillation (ADD). ADD uses score distillation, where the model learns from existing image-synthesis models, and adversarial loss, which enhances the model's ability to differentiate between real and generated images, improving the realism of the output.
Stability detailed the model's inner workings in a research paper released Tuesday that focuses on the ADD technique. One of the claimed advantages of SDXL Turbo is its similarity to Generative Adversarial Networks (GANs), especially in producing single-step image outputs.
Glenn Zorpette: Hello and welcome to Fixing the Future, an IEEE Spectrum podcast where we look at concrete solutions to some big problems. I’m your host, Glenn Zorpette, Editorial Director at Spectrum. And before we start, I just want to tell you that you can get the latest coverage from some of Spectrum‘s most important beats - including AI, climate change, and robotics - by signing up for one of our free newsletters. Just go to spectrum.ieee.org/newsletters to subscribe.
Electronic quartz watches arrived on the scene around 1970, and even today, they have advantages over their smartwatch brethren with batteries that last years, not days. But the motor that drives the hour and minute hands of the watch hasn’t really changed since then. Now, French company SilMach is using a new wristwatch to demonstrate its advanced silicon MEMS technology with a new watch movement that’s so efficient you might only need to change the battery about once a decade. Here to talk about that watch and the technology behind it is SilMach’s co-CEO and Chief Sales Officer, Pierre-Francois Louvigne, and also Jean-Baptiste Carnet, the co-CEO and Chief Financial Officer. Pierre Francois and Jean-Baptiste, welcome to the show.
Pierre-Francois Louvigne: Welcome.
Jean-Baptiste Carnet: Thank you for having us.
Louvigne: Thank you.
Zorpette: Glad to have you here. So my first question, the question that popped into my mind when I first read about your remarkable new watch motor is, why make a tiny electric motor now, at this time, for an analog watch? Aren’t smartwatches taking over the wristwatch market now, the Apple Watch, and so on? Aren’t those the thing everyone seems to be buying?
Louvigne: Yeah. Thank you for inviting us in this talk. Thank you very much. What we can say is that in the quartz watch, there is this technology name Lavet motor since more than 50 years. And if you open a classic quartz watch, you will see that there is a motor that is old technology, electromagnetic technology. And we invented at SilMach a new motor based on the most advanced technology and that is fully compatible with electronics.
Zorpette: So you have a particular strategy or a kind of watch in mind that you think will grow in the future?
Louvigne: The point is that this technology is obviously dedicated first to the smartwatch market because this market is ready to use these micromotors.
Zorpette: So you don’t mean the smartwatch that most people think of, which is the Apple Watch, which has no hands at all. I mean, no physical hands. It’s just a display screen. You seem to be referring to what is sometimes called the hybrid smartwatch or the hybrid-connected wristwatch. Is that correct?
Louvigne: Yes, it’s correct. Yes. The objective is to give the opportunity to any watchmaker, including connected watchmakers, that it’s possible now to use a motor to drive hands on a PCB, on the electronic board. And offering this opportunity, we think that those makers can design new watches.
Zorpette: So who are some of the companies that make these hybrid smartwatches?
Louvigne: I think the most advanced company is Withings.
Zorpette: Withings.
Louvigne: Withings. It’s a French brand. And the market that they are targeting with the watch is the health market. And we believe that in this market, the people are willing to have like a classic watch; they can say also vintage look. And if you want to do that, then you need motor to drive the hands.
Zorpette: Physical hands.
Louvigne: Physical hands, yes, correct.
Zorpette: So Withings is a big name in this category, but there are others that are in the category, correct?
Louvigne: Yeah, there is Garmin. Everybody knows Garmin. Fossil also, that is a big player. They are all looking for a part of the market. Garmin is more for sport activity. Fossil is more on fashion design. And Withings is for health.
Zorpette: So for listeners who might not be familiar with it, this is a wristwatch. And when you look at it, it looks like an old-school, a conventional analog wristwatch. However, they often have small electronic screens that show information. And in fact, the watch can also typically connect to your smartphone, so it can gather data from your smartphone. These watches often have accelerometers or blood pressure monitors and so on in them. So they typically have a lot of electronics, because not only do they have these sensors, but they’ve got to have the motors. And if I understand you correctly, your motor is more compact and efficient, which gives you advantages in this space.
Louvigne: Yes, right. One of the big advantages of the motor is that it is very compact. Roughly, you gain 50 percent in volume. Could be footprint, could be height, about 50 percent. So it’s [crosstalk].
Zorpette: 50 percent more room inside the watch case.
Louvigne: Yes, yes, yes. And as you said, effectively in this type of watch, you have a lot of very advanced technology. And now the motor is as advanced as the other function in the watch. That’s the big difference now.
Zorpette: So tell us a little bit about your wristwatch motor. I believe you call it the MEMS box is how you refer to it. What are the advantages that your watch motor has if you are going to integrate it with other electronics on a tiny circuit board that goes inside a wristwatch?
Louvigne: The very big change compared to the current technology, the Lavet one, is that the MEMS box--
Zorpette: So the existing motor is called the Lavet motor—
Louvigne: Yeah, the Lavet motor.
Zorpette: —as you mentioned.
Louvigne: From the name of the inventor, Marius Lavet. He was a French guy in the ‘30s, 1936, exactly. And he invented this technology that is in each of quartz watch today, more than one billion of quartz watch. So this technology is the only one you can use so far, okay? But the motor is not coming from the electronics. So it’s electromagnetic. It’s like a bulky micromotors, and you have to screw the motor on the PCB. Screw it. So you imagine the cost of screwing a motor on a PCB. In our case, the MEMS box is designed to be SMT-compatible.
Zorpette: So you just use surface mount soldering technology to mount it right to the circuit board?
Louvigne: Yes, correct. It’s like any other electronic component. You can handle it and solve it on the PCB as another one.
Zorpette: So Jean-Baptiste, what are some of the advantages now with this motor? What are some of the things that you now have in your watch that you couldn’t have with the old-style Lavet motor?
Carnet: Yes. As Pierre-Francois mentioned, it’s more compact. It’s much thinner. And inside the hybrid smartwatch, people have to imagine that almost half of the space inside the watch is actually dedicated just to the micromotor as it is today. And the little sensors, all the technology, all the know-how of the brands that are developed today, they have to adjust around half of the space already being taken by the micromotor. So it’s by far the biggest part inside of the watch, and making it much more compact, about 50 percent, much thinner, either allows for new designs of watches where you could make much smaller watches. For example, we know that the Garmin watches are pretty bulky. Or you could keep the same design as today, but implement more technology inside of it because you have more space, or make it last longer with a bigger battery, for example, because you freeze quite a lot of space. So that’s a big point. The SMT compatibility is also very interesting because as you get rid of the labor-intensive aspect of assembling a watch, you’re now free to assemble it anywhere you want. You don’t need to maybe go to a country where labor is more affordable. You can imagine assembling it in Europe, assembling it in the US, which is currently not possible. Also, the motor is anti-magnetic, which is interesting because the sensor interactivity can derail the current motor a little bit, or the interaction with magnets inside the woman’s purse, for example. Watchmakers told us, “Oh, that’s a very interesting feature because it’s a problem we have right now.”
Zorpette: How about the energy usage and the precision of the tick marks as it goes around the face of the watch?
Carnet: Yeah. That’s also one aspect of it is, first, the motor is consuming less energy also than current technology. So you can imagine having a longer battery life as well. That’s why the watch we are launching with the technology can offer more than 10 years of battery on a regular battery that you can buy anywhere. And also, as you said, the freedom of movement is an important feature because the motor is pretty much electronics. You can program it, pilot it however you want. You can have it go forward, backward, faster, slower. And what watch enthusiasts are interested about is you can either have it tick, for example, the seconds like a traditional quartz watch, or you can have it make a much more fluid movement, which is somewhat of a holy grail for watch enthusiasts. So that’s things that become possible with our technology that was not with traditional ones. And that’s what watch designers since we unveiled the technology a couple weeks ago, and we will keep on doing it at CES Engineering.
Zorpette: So here’s my own pet peeve about watches. When I was a young man and I did a lot of scuba diving, I actually had a watch that had tiny tritium gas markings, so it glowed all the time. It didn’t need to be charged with a bright light. And I loved this watch because I could read it clearly underwater. Even at night, it was bright enough. And also, at night when I was sleeping, if I woke up in the middle of the night and the watch was on my bedside table, I could see what time it was without having to turn a light on or anything like that. And I know that those watches can be tricky. They go dead after five or six or seven years because the tritium half-life, they’re too dim to read. But I’ve always wondered if it would be possible using perhaps some ultra-efficient light-emitting diode or other technology to recreate that somehow. If you had enough space for a battery and other power supplies, if you had enough room in the case, if you could create these watches, which were popular at one time. If you go back even to World War II, they made watches using radium and so on. It just seemed such a practical thing when I had it, other than the fact that it went dead. But is that more possible now, technologically, with a very tiny and efficient motor?
Louvigne: Yeah, clearly it’s possible. I don’t know if you know some of the watch coming from Timex. They have a specific patent on that. It’s like a luminescent dial that gives you the opportunity to see what time is it even in the dark, fully dark. So yes, it’s possible to combine the technology with other ones providing such a result. Yeah.
Zorpette: So you mentioned Timex. And in fact, that gets me into my next question, which is, have you had interest from any major watchmakers yet in your MEMS box motor?
Louvigne: Yes, we know most of them— we know most of them because those companies, they were looking for the progress we made on the technology. So we have been in contact with them for more than 15 years. So yes, it’s done. The particular partnership we have with Timex was based on the fact that we are a small company. We are about 30 people in France. We are in the good region for watchmaking because it’s the former one. In the past, there was a huge activity in watchmaking industry. So we are in the good region for that. And there is one important partner we have that is a subsidiary of Timex in France. And this company named Fralsen is making all the small parts used in quartz movements. So it was obvious that the— not the compatibility, but the synergy between our very new technology and those classic parts was very interesting. And then we went to the Timex Group and we decided to build a joint venture, so a common company that is based in France, and the name is TiMach. Timex, SilMach, TiMach.
Zorpette: TiMach. Okay. And so in the future, we may be seeing this motor in watches from Timex or other companies.
Louvigne: Yeah. I mean, the objective of the joint venture is to sell the technology all over the world. It’s obviously not specific to Timex. They will use it in their watch. But no, it’s open to the market widely.
Zorpette: So I guess another question that might be on the minds of some of our listeners is, why did it take so long for someone to harness the technology of silicon microelectromechanical systems or silicon MEMS? We mentioned that silicon MEMS technology has been around for decades, 20 or 30 years, as far as I know, but yours is the first to harness it for a wristwatch motor. Was there some challenges that delayed this use?
Louvigne: Yes. Clearly, what we are doing is very unique because there is no other company or even university that made this development, okay? This is very unique because, in fact, we are combining the MEMS technology that is very advanced. You have to go in clean rooms to manufacture the silicon. But as soon as you will finish the silicon parts, you made only a part of the journey development, okay? You have to combine those silicon parts with more classic parts coming from the watchmaking industry. And this is what we do. We call this hybridization, meaning that we connect the silicon with classic micromechanics. And we are the only company that makes that in the world. So we have invented the motor, but we have also invented the technology for the assembly. This is completely new. And we have patents in both sectors. So yeah, you need a lot of time for developing all those steps of the technique.
Zorpette: Well, thank you both very much. Again, I’ve been talking with Pierre-Francois Louvigne and Jean-Baptiste Carnet. They’re both with SilMach, and they have a remarkable silicon MEMS wristwatch motor called the MEMS box. And we’ve heard a lot about the promise and challenges of this watch. For IEEE Spectrum’s Fixing the Future, I’m Glenn Zorpette and I hope you’ll join us next time.
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Security researchers are tracking what they say is the “mass exploitation” of a security vulnerability that makes it possible to take full control of servers running ownCloud, a widely used open-source filesharing server app.
The vulnerability, which carries the maximum severity rating of 10, makes it possible to obtain passwords and cryptographic keys allowing administrative control of a vulnerable server by sending a simple Web request to a static URL, ownCloud officials warned last week. Within four days of the November 21 disclosure, researchers at security firm Greynoise said, they began observing “mass exploitation” in their honeypot servers, which masqueraded as vulnerable ownCloud servers to track attempts to exploit the vulnerability. The number of IP addresses sending the web requests has slowly risen since then. At the time this post went live on Ars, it had reached 13.
“We're seeing hits to the specific endpoint that exposes sensitive information, which would be considered exploitation,” Glenn Thorpe, senior director of security research & detection engineering at Greynoise, said in an interview on Mastodon. “At the moment, we've seen 13 IPs that are hitting our unadvertised sensors, which indicates that they are pretty much spraying it across the internet to see what hits.”
Enlarge / The Ekobot autonomous weeding robot roving around an onion field in Sweden. (credit: Ekobot AB)
Anybody who has pulled weeds in a garden knows that it's a tedious task. Scale it up to farm-sized jobs, and it becomes a nightmare. The most efficient industrial alternative, herbicides, have potentially devastating side effects for people, animals, and the environment. So a Swedish company named Ekobot AB has introduced a wheeled robot that can autonomously recognize and pluck weeds from the ground rapidly using metal fingers.
The four-wheeled Ekobot WEAI robot is battery-powered and can operate 10–12 hours a day on one charge. It weighs 600 kg (about 1322 pounds) and has a top speed of 5 km/h (2.5 mph). It's tuned for weeding fields full of onions, beetroots, carrots, or similar vegetables, and it can cover about 10 hectares (about 24.7 acres) in a day. It navigates using GPS RTK and contains safety sensors and vision systems to prevent it from unintentionally bumping into objects or people.
To pinpoint plants it needs to pluck, the Ekobot uses an AI-powered machine vision system trained to identify weeds as it rolls above the farm field. Once the weeds are within its sights, the robot uses a series of metal fingers to quickly dig up and push weeds out of the dirt. Ekobot claims that in trials, its weed-plucking robot allowed farmers to grow onions with 70 percent fewer pesticides. The weed recognition system is key because it keeps the robot from accidentally digging up crops by mistake.
Each year, IEEE pays tribute to technical professionals whose outstanding contributions have made a lasting impact on technology and the engineering profession for humanity. The IEEE Awards program seeks nominations annually for IEEE’s top awards—Medals and Recognitions—that are given on behalf of the IEEE Board of Directors.
You don’t have to be an IEEE member to receive, nominate, or endorse someone for an award.
Nominations for 2025 Medals and Recognitions will be open from 1 December to 15 June 2024. All nominations must be submitted through the IEEE Awards online portal set up for Medals and Recognitions.
These awards are presented at the annual IEEE Honors Ceremony. The 2024 IEEE Vision, Innovation, and Challenges Summit and Honors Ceremony will be held on 3 May at the Encore Boston Harbor. Planning for the upcoming event is currently underway, and more information will be announced in the coming months.
The IEEE Awards Board has an ongoing initiative to increase diversity among the selection committees and candidates, including their technical discipline, geography, and gender. You can help by nominating a colleague for one of the following awards.
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This is a sponsored article brought to you by LEMO.
About a decade ago, during a business trip to China, British engineer Alan Hudd had a shock. At the end of a visit at a major textile dyeing factory, his customer took him behind the buildings to show a horrific scene: A blood-red river—wastewater from the dye baths leaching into the soil and entering the rivers. “You must find a solution for this!”
It is no coincidence that the customer turned to Hudd. He used to be a rocket scientist for the British Ministry of Defense. He had contributed to the invention of Shell mineral oil, which is still being used in our cars. He had created Xennia Technology as well, whose inkjet technologies revolutionized other highly polluting processes, such as the surface treatment for ceramic tiles. So, the engineer was well- placed to pick up the challenge without a moment’s hesitation: He spent a decade developing an inkjet solution specifically for textiles and even created a new dedicated start-up.
Founded in 2013, Alchemie Technology plans to roll out its technology at scale this year, with a clear and ambitious message: Alchemie’s digital dying technology will change the world.
Meanwhile, the environmental damage discovered by Hudd 10 years ago has become even worse. Unsurprisingly: apart from some occasional optimizations (less chemicals, better waste recycling), processes haven’t changed. Miles of fabrics are immersed in gigantic “washing machines” full of dye and water. Then excess dye is rinsed in a whole series of high-temperature baths. For finishing treatments (anti-perspirant, crease-protection, waterproofing, etc.) a new series of chemical baths and high energy treatment is used.
Alchemie’s machines dye cotton using 95 percent less water and 70 percent less energy. They dye polyester using 95 percent less water and 85 percent less energy. The reduction in quantities of dye and finishing products is also drastic.
There is a massive waste, alerts Alchemie Technology: About 30 tons of water is used to dye a single ton of fabric.
The textile industry innovator mentions other horrendous figures during its presentations to investors and potential customers. The fashion industry is responsible for 10 percent of carbon emissions, textile dyeing alone for 3 percent. If nothing changes, the dyeing industry will continue producing 2.5 gigatons of carbon dioxide by 2050. Dyeing also generates 20 percent of industrial water pollution (the second main cause on a global level).
Without changing anything, the industry itself will be in danger: increasing water shortage may jeopardize its activities and the energy cost explosions further erode its low profit margins. Indeed, many companies disappear—the dyeing industry is, well, dying.
Considering the scope and the long-standing history of the issue, it is quite surprising that no fundamental solutions have been found so far. Alchemie Technology suggests several reasons. For too long, we have turned a blind eye on the massive pollution generated. It has only been for the last few years that pressure can no longer be ignored. There is also the usual resistance to change (resulting costs, giving up processes established for decades, etc.), in addition to uncertainties about the benefits.
Incremental improvements had no chance to trigger real change. An enormous leap forward was necessary, a radical solution. And this is precisely where Alchemie Technology enters with Endeavour and Novara.
Alchemie Technology’s Endeavour, a machine that prints on the fabric, instead of immersing it into baths. Alchemie Technology
Endeavor is similar to a digital printing machine used for producing publications such as CONNECTED. A fabric roll is fed in, whereupon a bar equipped with more than 1400 individually controlled nozzles jets drops of dye at high speed. This “printing” is rather intense, since the drops are much larger than those of a paper printer and there are 1.2 billion drops per linear meter. On the other side of the fabric, vacuum is created to ensure the dye penetrates the entire length of the fabric fibers, without creating any excess dye. Finetuning the process was what took longest for Alchemie.
Unsurprisingly, Alchemie could not possibly test every dye on every fabric. It started with woven cotton and polyester. For the latter, being hydrophobic, the dye is jetting on both sides of the fabric and fixed by infrared light. Using Alchemie’s technology, cotton needs only to be jetted on one side of the fabric for complete penetration and even dyeing on both sides – this was a Eureka discovery for Alchemie.
Novara, the second machine, carries out the finishing treatments. The process is similar: chemicals are jetted on the surface of the fabric.
The quality of the final result is the equivalent of that obtained through classic processes, says Alchemie. As for the efficiency of the process, it has absolutely no equivalent.
As a matter of fact, Alchemie’s liquid application technology circum- vents the central issue of classic dyeing, the immersion into multiple baths. It is a non-contact method of jetting dye onto the surface of fabrics while achieving the same results as traditional methods. Alchemie Technology’s machines have been specifically designed to reduce the water, dyes, chemicals, and energy used to a strict minimum.
The results reported by the start-up are spectacular. These machines dye cotton using 95 percent less water and 70 percent less energy. They dye polyester using 95 percent less water and 85 percent less energy. The reduction in quantities of dye and finishing products is also drastic.
It doesn’t take an expert to guess the environmental impact that such a solution could have on a large scale. With climate protection, we have become used to minute progress, at the best. Here we have a revolution.
The solution also benefits the industry. The specter of water short- age and energy costs would no longer be daunting. Operating costs would decrease, increasing margins.
According to Alchemie, purchasing one or several Endeavours (they will cost about a million pounds — about U.S. $1,24 million — each) would pay off very quickly. The machines would also contribute to improving working environment (modern printers rather than “giant Turkish baths”). Much better for attracting new generations of employees.
Dyers are the main customers of Alchemie, but it has also been working on convincing the sector’s decision-makers — major clothing brands. They could put pressure on their suppliers to embark in this revolution. Due to environmental awareness. Or because they want innovative products. Or for their brand image. Or all of this at the same time.
Alchemie Technology also has joint development projects with several major brands (names not available due to NDA) whose suppliers test the quality, performance, and savings of this new way of dyeing textiles.
However, Alchemie is full of trust, given the massive interest in its solutions. The big fashion brands have set their 2030 objectives for sustainable development, in particular for water and energy consumption as well as carbon emissions. Endeavour and Novara have arrived just in time.
If everything goes well, meeting the demand would be Alchemie’s only concern.
The company plans to deliver about 15 machines this year, about 50 in 2024, 500 in 2025 and to continue its exponential growth. The potential is not unlimited, but there it is: Alchemie estimates its market at about 30,000 machines.
In case of a huge success, its U.K. production capacity will not be sufficient. The start-up is planning to rely on external partners for manufacturing basic elements. R&D and core technology (namely the printing bars) should stay in the U.K.
Alchemie Technology will also open demo centers in the major regions of textile dyeing. The first one in Taiwan (global capital of finishing treatments). Then in Portugal, Turkey, but mainly in Asia: Vietnam, Indonesia, India, Pakistan, Bangladesh...
Will digital dyeing technology change the world? You will soon find out at a fashion boutique close to you.
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A prolific espionage hacking group with ties to China spent over two years looting the corporate network of NXP, the Netherlands-based chipmaker whose silicon powers security-sensitive components found in smartphones, smartcards, and electric vehicles, a news outlet has reported.
The intrusion, by a group tracked under names including "Chimera" and "G0114," lasted from late 2017 to the beginning of 2020, according to Netherlands-based NCR, which cited “several sources” familiar with the incident. During that time, the threat actors periodically accessed employee mailboxes and network drives in search of chip designs and other NXP intellectual property. The breach wasn’t uncovered until Chimera intruders were detected in a separate company network that connected to compromised NXP systems on several occasions. Details of the breach remained a closely guarded secret until now.
NCR cited a report published (and later deleted) by security firm Fox-IT, titled Abusing Cloud Services to Fly Under the Radar. It documented Chimera using cloud services from companies including Microsoft and Dropbox to receive data stolen from the networks of semiconductor makers, including one in Europe that was hit in “early Q4 2017.” Some of the intrusions lasted as long as three years before coming to light. NCR said the unidentified victim was NXP.
Enlarge / Still examples of images animated using Stable Video Diffusion by Stability AI. (credit: Stability AI)
On Tuesday, Stability AI released Stable Video Diffusion, a new free AI research tool that can turn any still image into a short video—with mixed results. It's an open-weights preview of two AI models that use a technique called image-to-video, and it can run locally on a machine with an Nvidia GPU.
Last year, Stability AI made waves with the release of Stable Diffusion, an "open weights" image synthesis model that kick started a wave of open image synthesis and inspired a large community of hobbyists that have built off the technology with their own custom fine-tunings. Now Stability wants to do the same with AI video synthesis, although the tech is still in its infancy.
Right now, Stable Video Diffusion consists of two models: one that can produce image-to-video synthesis at 14 frames of length (called "SVD"), and another that generates 25 frames (called "SVD-XT"). They can operate at varying speeds from 3 to 30 frames per second, and they output short (typically 2-4 second-long) MP4 video clips at 576×1024 resolution.
Enlarge / A blog post from AWS chief evangelist Jeff Barr shows the Workspaces Thin Client setup. (credit: Jeff Barr/Amazon)
Amazon has turned its Fire TV Cube streaming device into a thin client optimized for Amazon Web Services (AWS).
Amazon's Workspaces Thin Client also supports Amazon's Workspaces Web, for accessing virtual desktops from a browser, and AppStream.
The computer is a Fire TV Cube with a new software stack. All the hardware—from the 2GB of LPDDR4x RAM and 16GB of storage, to the Arm processor with 8 cores, including four running at up to 2.2 GHz—remain identical whether buying the device as an Alexa-powered entertainment-streaming device or thin client computer. Both the Fire TV Cube and Workspaces Thin Client run an Android Open Source Project-based Android fork (for now).
Joy Buolamwini‘s AI research was attracting attention years before she received her PhD from the MIT Media Lab in 2022. As a graduate student, she made waves with a 2016 TED talk about algorithmic bias that has received more than 1.6 million views to date. In the talk, Buolamwini, who is Black, showed that standard facial detection systems didn’t recognize her face unless she put on a white mask. During the talk, she also brandished a shield emblazoned with the logo of her new organization, the Algorithmic Justice League, which she said would fight for people harmed by AI systems, people she would later come to call the excoded.
In her new book, Unmasking AI: My Mission to Protect What is Human in a World of Machines, Buolamwini describes her own awakenings to the clear and present dangers of today’s AI. She explains her research on facial recognition systems and the Gender Shades research project, in which she showed that commercial gender classification systems consistently misclassified dark-skinned women. She also narrates her stratospheric rise—in the years since her TED talk, she has presented at the World Economic Forum, testified before Congress, and participated in President Biden’s roundtable on AI.
While the book is an interesting read on a autobiographical level, it also contains useful prompts for AI researchers who are ready to question their assumptions. She reminds engineers that default settings are not neutral, that convenient datasets may be rife with ethical and legal problems, and that benchmarks aren’t always assessing the right things. Via email, she answered IEEE Spectrum‘s questions about how to be a principled AI researcher and how to change the status quo.
One of the most interesting parts of the book for me was your detailed description of how you did the research that became Gender Shades: How you figured out a data collection method that felt ethical to you, struggled with the inherent subjectivity in devising a classification scheme, did the labeling labor yourself, and so on. It seemed to me like the opposite of the Silicon Valley “move fast and break things” ethos. Can you imagine a world in which every AI researcher is so scrupulous? What would it take to get to such a state of affairs?
Joy Buolamwini: When I was earning my academic degrees and learning to code, I did not have examples of ethical data collection. Basically if the data were available online it was there for the taking. It can be difficult to imagine another way of doing things, if you never see an alternative pathway. I do believe there is a world where more AI researchers and practitioners exercise more caution with data collection activities, because of the engineers and researchers who reach out to the Algorithmic Justice League looking for a better way. Change starts with conversation, and we are having important conversations today about data provenance, classification systems, and AI harms that when I started this work in 2016 were often seen as insignificant.
What can engineers do if they’re concerned about algorithmic bias and other issues regarding AI ethics, but they work for a typical big tech company? The kind of place where nobody questions the use of convenient datasets or asks how the data was collected and whether there are problems with consent or bias? Where they’re expected to produce results that measure up against standard benchmarks? Where the choices seem to be: Go along with the status quo or find a new job?
Buolamwini: I cannot stress the importance of documentation. In conducting algorithmic audits and approaching well-known tech companies with the results, one issue that came up time and time again was the lack of internal awareness about the limitations of the AI systems that were being deployed. I do believe adopting tools like datasheets for datasets and model cards for models, approaches that provide an opportunity to see the data used to train AI models and the performance of those AI models in various contexts is an important starting point.
Just as important is also acknowledging the gaps, so AI tools are not presented as working in a universal manner when they are optimized for just a specific context. These approaches can show how robust or not an AI system is. Then the question becomes is the company willing to release a system with the limitations documented or are they willing to go back and make improvements.
It can be helpful to not view AI ethics separately from developing robust and resilient AI systems. If your tool doesn’t work as well on women or people of color, you are at a disadvantage compared to companies who create tools that work well for a variety of demographics. If your AI tools generate harmful stereotypes or hate speech you are at risk for reputational damage that can impede a company’s ability to recruit necessary talent, secure future customers, or gain follow-on investment. If you adopt AI tools that discriminate against protected classes for core areas like hiring, you risk litigation for violating anti-discrimination laws. If AI tools you adopt or create use data that violates copyright protections, you open yourself up to litigation. And with more policy makers looking to regulate AI, companies that ignore issues or algorithmic bias and AI discrimination may end up facing costly penalties that could have been avoided with more forethought.
“It can be difficult to imagine another way of doing things, if you never see an alternative pathway.” —Joy Buolamwini, Algorithmic Justice League
You write that “the choice to stop is a viable and necessary option,” and say that we can reverse course even on AI tools that have already been adopted. Would you like to see a course reversal on today’s tremendously popular generative AI tools, including chatbots like ChatGPT and image generators like Midjourney? Do you think that’s a feasible possibility?
Buolamwini: Facebook (now Meta) deleted a billion faceprints around the time of a US $650 million settlement after they faced allegations of collecting face data to train AI models without the expressed consent of users. Clearview AI stopped offering services in a number of Canadian provinces after investigations into their data collection process were challenged. These actions show that when there is resistance and scrutiny there can be change.
You describe how you welcomed the AI Bill of Rights as an “affirmative vision” for the kinds of protections needed to preserve civil rights in the age of AI. That document was a nonbinding set of guidelines for the federal government as it began to think about AI regulations. Just a few weeks ago, President Biden issued an executive order on AI that followed up on many of the ideas in the Bill of Rights. Are you satisfied with the executive order?
Buolamwini: The EO on AI is a welcomed development as governments take more steps toward preventing harmful uses of AI systems, so more people can benefit from the promise of AI. I commend the EO for centering the values of the AI Bill of Rights including protection from algorithmic discrimination and the need for effective AI systems. Too often AI tools are adopted based on hype without seeing if the systems themselves are fit for purpose.
You’re dismissive of concerns about AI becoming superintelligent and posing an existential risk to our species, and write that “existing AI systems with demonstrated harms are more dangerous than hypothetical ‘sentient’ AI systems because they are real.” I remember a tweet from last June in which you talked about people concerned with existential risk and said that you “see room for strategic cooperation” with them. Do you still feel that way? What might that strategic cooperation look like?
Buolamwini: The “x-risk” I am concerned about, which I talk about in the book, is the x-risk of being excoded—that is, being harmed by AI systems. I am concerned with lethal autonomous weapons and giving AI systems the ability to make kill decisions. I am concerned with the ways in which AI systems can be used to kill people slowly through lack of access to adequate healthcare, housing, and economic opportunity.
I do not think you make change in the world by only talking to people who agree with you. A lot of the work with AJL has been engaging with stakeholders with different viewpoints and ideologies to better understand the incentives and concerns that are driving them. The recent UK AI Safety Summit is an example of a strategic cooperation where a variety of stakeholders convened to explore safeguards that can be put in place on near-term AI risks as well as emerging threats.
As part of the Unmasking AI book tour, Sam Altman and I recently had a conversation on the future of AI where we discussed our varying viewpoints as well as found common ground: Namely that companies cannot be left to govern themselves when it comes to preventing AI harms. I believe these kinds of discussions provide opportunities to go beyond incendiary headlines. When Sam was talking about AI enabling humanity to be better—a frame we see so often with the creation of AI tools—I asked which humans will benefit. What happens when the digital divide becomes an AI chasm? In asking these questions and bringing in marginalized perspectives, my aim is to challenge the entire AI ecosystem to be more robust in our analysis and hence less harmful in the processes we create and systems we deploy.
What’s next for the Algorithmic Justice League?
Buolamwini: AJL will continue to raise public awareness about specific harms that AI systems produce, steps we can put in place to address those harms, and continue to build out our harms reporting platform which serves as an early warning mechanism for emerging AI threats. We will continue to protect what is human in a world of machines by advocating for civil rights, biometric rights, and creative rights as AI continues to evolve. Our latest campaign is around TSA use of facial recognition which you can learn more about via fly.ajl.org.
Think about the state of AI today, encompassing research, commercial activity, public discourse, and regulations. Where are you on a scale of 1 to 10, if 1 is something along the lines of outraged/horrified/depressed and 10 is hopeful?
Buolamwini: I would offer a less quantitative measure and instead offer a poem that better captures my sentiments. I am overall hopeful, because my experiences since my fateful encounter with a white mask and a face tracking system years ago has shown me change is possible.
THE EXCODED
To the Excoded
Resisting and revealing the lie
That we must accept
The surrender of our faces
The harvesting of our data
The plunder of our traces
We celebrate your courage
No Silence
No Consent
You show the path to algorithmic justice require a league
A sisterhood, a neighborhood,
Hallway gatherings
Sharpies and posters
Coalitions Petitions Testimonies, Letters
Research and potlucks
Dancing and music
Everyone playing a role to orchestrate change
To the excoded and freedom fighters around the world
Persisting and prevailing against
algorithms of oppression
automating inequality
through weapons of math destruction
we Stand with you in gratitude
You demonstrate the people have a voice and a choice.
When defiant melodies harmonize to elevate
human life, dignity, and rights.
The victory is ours.
Reference: https://ift.tt/QmPstvr
Many of us have gotten used to being able to dampen unwanted sound, thanks to the noise-cancellation technology found in, for example, Apple’s AirPods Pro earbuds. But this tech gets you only so far: Noise cancellation works just for relatively low frequencies, and the overall hearing protection that earbuds can offer is also relatively limited. Earplugs or over-the-ear defenders are an option, but they block wanted as well as unwanted sounds. There are industrial solutions that pass through sounds in specific frequency ranges, but these are targeted at speech. As a musician who plays loud music, I want a way to protect my hearing and to be able to hear myself, my bandmates, and the audience with high fidelity.
For years, I have been trying to improve my personal audio-monitoring situation without going to the expense of the systems used by professional touring bands, which include custom-molded earpieces. Now, after countless versions of wiring things together, and even designing my own audio mixers, I finally have a DIY solution that works within a reasonable budget. My approach was to adapt an idea used in some pass-through systems, placing ambient microphones on the outside of sound-isolating headphones. I would capture the signal from these external mics at high quality and feed it into the headphones at the desired volume.
Of course, easier said than done. For my first prototype, I bought a set of US $40 ear defenders that had a built-in AM/FM radio, which fed into small speakers in the ear “cans” and extracted the radio electronics to make some space. I then hooked up a chain of breakout boards from my full-time employer, SparkFun Electronics: A $7 ICS-40180 MEMS microphone, a $6 TSH82 op-amp, and an $11 TPA2016D2 class-D amplifier. My initial testing went okay, in that I could hear the sound from the mics when I wore the defenders, but I quickly noticed a problem.
The author needed a properly shielded grounded cable (1) to bring in a signal from the left microphone (2) to the audio codec board (3), which is mounted on a custom circuit board (4) inside the right headphone. Also mounted on the board are the ESP32 microcontroller (5) and a volume control and audio jack (6). James Provost
I’m a drummer. When I played very gently on my drum set, the audio was clear, but as soon as I hit a drum with even moderate force, the pass-through signal became rudely distorted, or clipped. Puzzled, I checked the specs of the microphone. The datasheet indicated it had an acoustic overload point (AOP) of 124 decibels. It seemed like the microphone should be more than capable of handling an acoustic drum set—which, according to my calibrated sound-level meter, was producing a peak of only 115 dB during my hardest-hitting playing.
The microphone’s breakout board applies a gain of 64x, using two stages. My first thought was to reduce this gain. Maybe the clipping was happening at only the first gain stage. Unfortunately, even with this gain eliminated, the clipping remained. I then tested the raw MEMS microphone output by feeding it into some “pro grade” mic preamps. With this setup, I was able to see that the problem wasn’t the amplification stages but that the mics themselves were producing the clipping. Through this test, I learned a valuable lesson: A mic’s listed AOP is the point at which the microphone will produce a 10 percent total harmonic distortion, and so noticeable clipping can actually start to happen well below this level.
I was on the hunt for another cheap small MEMS mic that could handle louder sound sources. I found the Vesper VM2020, with an impressive AOP of 149 dB! I spun up a new breakout board for the VM2020 and was testing it in no time. Initial results were good—the VM2020 did not clip the signal no matter how hard I played! However, due to the middling sensitivity of this microphone (–63 dB), it was necessary to add a lot of gain to the signal. Combined with the microphone’s equally middling signal-to-noise ratio of 50 dB, this resulted in too much hiss in the output for my musical needs. I went on the hunt for yet another microphone. I found the $5 AOM-5035L by PUI Audio, which is an electret condenser type. This microphone had three important specs: high AOP (135 dB), good sensitivity (–35 dB), and a better signal-to-noise ratio of 75 dB.
The WM8960 audio codec translates incoming sound signals—whether they’re analog from the microphones, an audio cable, or digital signals received from the ESP32 microcontroller—into audible sounds that a wearer can hear. The ESP32 also configures the codec board on startup.James Provost
Around the time of finding this microphone, I had just completed another breakout board for SparkFun. It was for the audio codec chip by Wolfson, the $18 WM8960. This board was more suited for this project than my previous choice, the TPA2016D2. The WM8960 has a quieter initial gain stage that’s designed for microphones. However, I now needed a microcontroller to initialize and control the WM8960. I chose the $10 ESP32 because it would allow me to operate the WM8960 and also accept audio via a Bluetooth connection from, say, my phone, and stream it to the WM8960.
I created a motherboard PCB to ensure everything fitted nicely into the right ear can of my hacked ear defenders. On the outside of each can I placed a microphone to provide stereo sound. (A detailed step-by-step guide is available on the SparkFun website.) Soon I was enjoying a clean audio signal with no clipping and no hiss during my drum rehearsals. But in a last wrinkle, I noticed that sometimes there was a small whining noise that would vary in pitch in the left audio channel. This became more pronounced when the batteries were getting low, and if I turned off the ESP32’s Bluetooth, some of the noise would go away. In an attempt to solve this, I first added a separate and dedicated ground connection from the left microphone back to the electronics in the right ear can. This reduced the whine but did not remove it entirely. I finally used a proper shielded microphone cable to connect the microphone to the WM8960. This eliminated the noise completely. Success! I’ve been playing away with protected hearing, and for less than $100 and some bench time, you too can have your very own custom set of Superheadphones!
Reference: https://ift.tt/ex2FGnbIEEE depends on volunteer members for many things, including organizing conferences, coordinating regional and local activities, writing standards, and deciding on IEEE’s future.
But because the organization can be complex, many members don’t know what resources and roles are available to them, and they might need training on how to lead groups. That’s why in 2013, the IEEE Member and Geographic Activities board established its Volunteer Leadership Program. VoLT, an MGA program, provides members with resources and an overview of IEEE, including its culture and mission. The program also offers participants training to help them gain management and leadership skills. Each participant is paired with a mentor to provide guidance, advice, and support.
Program specialist for IEEE’s Volunteer User Experience Stephen Torpie and long-time volunteer and Life Member Marc Apter discuss the benefits of the VoLT program with visitors to the exhibit booth at IEEE Sections Congress.Stephen Torpie
VoLT, which is celebrating its 10th anniversary this year, has grown steadily since its launch. In its first year, the program had 49 applicants and 19 graduates. Now nearly 500 members from all 10 IEEE regions and 165 sections have completed the program. This year the program received 306 applications, and it accepted 70 students to participate in the next six-month session.
“When I first got on the Board of Directors, I didn’t realize all the complexities of the organization, so I thought it would be helpful to provide a broad background for others to help them understand IEEE’s larger objectives,” says Senior Member Loretta Arellano, the mastermind behind VoLT. “The program was developed so that volunteers can quickly learn the IEEE structure and obtain leadership skills unique to a volunteer organization.
“IEEE is such a large organization, and typically members get involved with just one aspect and are never exposed to the rest of IEEE. They don’t realize there are a whole lot of resources and people to help them.”
Before applying to VoLT, members are required to take 10 courses that provide them with a comprehensive introduction to IEEE. The free courses are available on the IEEE Center for Leadership Excellence website.
Along with their application, members must include a reference letter from an IEEE volunteer.
“The VoLT program taught me how expansive IEEE’s network and offerings are,” says Moriah Hargrove Anders, an IEEE graduate student member who participated in the program in 2017. “The knowledge [I gained] has guided the leadership I take back to my section.”
Participants attend 10 to 12 webinars on topics such as soft skills, leadership, and stress management. VoLT also trains them in IEEE Collabratec, IEEE vTools, IEEE Entrepreneurship, and other programs, plus the IEEE Code of Ethics.
“IEEE is such a large organization, and typically members get involved with just one aspect and are never exposed to the rest of IEEE. They don’t realize there are a whole lot of resources and people to help them.” —Loretta Arellano
Program mentors are active IEEE volunteers and have held leadership positions in the organization. Six of the 19 mentors from the program’s first year are still participating in VoLT. Of the 498 graduates, 205 have been a mentor at least once.
VoLT participants complete a team project, in which they identify a problem, a need, an opportunity, or an area of improvement within their local organizational unit or the global IEEE. Then they develop a business plan to address the concern. Each team presents a video highlighting its business plan to VoLT’s mentors, who evaluate the plans and select the three strongest. The three plans are sent to each individual’s IEEE region director and section leader to consider for implementation.
“The VoLT program helped me to reaffirm and expand my knowledge about IEEE,” Lizeth Vega Medina says. The IEEE senior member graduated from the program in 2019. “It also taught me how to manage situations as a volunteer.”
Each year, the program makes improvements based on feedback from students and the MGA board.
To acknowledge its anniversary, VoLT offered an exhibit booth in August at the IEEE Sections Congress in Ottawa. The event, held every three years, brings together IEEE leaders and volunteers from around the world. Recent VoLT graduates presented their team’s project. Videos of the sessions are available on IEEE.tv.
To stay updated on the program and its anniversary celebrations, follow VoLT on Facebook, Instagram, and LinkedIn.
Reference: https://ift.tt/oxDQwqm
It’s a summer night. On the rooftop of a quiet building, a set of panels cools the rooms within and keeps the lights on, removing heat and generating electricity using the coldness of the sky. That cold isn’t in the air around the building—the night is warm. Rather, the panels reach far beyond Earth’s atmosphere to tap the distant cold of deep space.
Sound crazy? Admittedly, this technology isn’t fully available just yet. But we have demonstrated that by directly using power generated by the cold universe, we can chill water to cool buildings by as much as 5 ºC during the day without electricity and light the night without wires or batteries. As the technology improves, we see it enabling solar panels that work at night as well as day, powering remote sensors.
From the time the first humans learned to harness fire, people have manipulated heat to do their bidding. Today, the art of turning heat from burning gas, nuclear fission, Earth’s core, the sun, and other sources into useful energy underpins modern life.
Edmon de Haro
With so much energy available from heat, we’ve ignored another source of power: cold. The coldness of deep space is a thermodynamic resource, and largely untapped. Yes, it’s far away, but distance doesn’t prevent its use, particularly when we consider just how cold the vast empty space of the universe is—approximately 3 kelvins.
We generally aren’t aware of this coldness because things around us, including sunlight and radiation bouncing back to us from the atmosphere, conspire to heat us up. But about a decade ago, our research group at Stanford designed a material that’s remarkably efficient at sending heat out to that reservoir of cold while preventing heating from both the sun and the environment. The material is so efficient, in fact, that it can cool itself below the temperature of its surroundings, even when sitting in direct sunlight.
That was pretty cool—literally. And when heat can spontaneously flow from an object on Earth to the universe, just like water flows from higher ground to the sea, it gives us an opportunity to harvest useful energy from it along the way.
In the case of moving water, a turbine harvests the energy in the flow to generate hydroelectricity. In the case of the flow of heat from Earth to deep space, we’ve got a couple of promising concepts developed, although we’re still trying to figure out the best mechanism.
Before we tell you about those ideas and prototypes, you need to understand the role radiation plays in maintaining Earth’s energy balance.
Radiation is one of three mechanisms for heat transfer. The other two are heat conduction and heat convection. The first arises from atoms vibrating against one another as typically occurs in a solid; the second arises from bulk movements of particles, such as gas molecules in air. Both conduction and convection require a medium through which to move heat. Radiation, in the form of traveling electromagnetic waves, does not require such a medium and can traverse a long distance.
Consider solar radiation, which carries heat from the sun to Earth’s surface. On a sunny day, you can feel your body heat up as it absorbs that sunlight. Earth-based objects radiate heat, too: On a clear night you’ll feel your body cool; some of that cooling is heat radiating into space.
While incoming radiation has become a mainstay for renewable energy in the form of solar energy, outgoing radiation has largely remained untapped for energy generation. That outgoing radiation sends the heat from an object on Earth to outer space, a reservoir with virtually limitless capacity. Removing heat this way can cool that object down tens of degrees below the temperature of its surroundings.
We can exploit the temperature difference by turning it into electricity through thermoelectric power generation. The working principle behind a thermoelectric generator is the Seebeck effect, which describes how a material develops a voltage difference in response to a temperature differential across it. We can manipulate the Seebeck effect in semiconductors by the controlled addition of impurities, or dopants.
Recall that dopants can turn their host semiconductors into either n-type semiconductors, with mobile negatively charged electrons, or p-type semiconductors, with mobile positively charged holes. In either case, when these semiconductors bridge a temperature differential, the electrons or the holes congregate near the colder end. So the n-type develops a positive voltage potential toward the hot side, while the p-type develops a negative voltage potential in the same direction.
A thermoelectric generator (TEG) consists of alternating pairs of n- and p-type semiconductors chained together so that the voltage gained from the positive temperature differential in an n-type adds to the voltage gained from the negative temperature differential in a p-type. By connecting a TEG between a hot reservoir and a cold one, the heat differential is captured as electricity.
With the ambient environment as a hot reservoir, we can use the coldness from deep space to create the cold reservoir.
To do this, we send heat out to space using what we call an emitter, which cools itself to a lower temperature than its surroundings. That’s a phenomenon known as radiative cooling. Then, a thermoelectric generator situated between the cold emitter and the now-hotter ambient surroundings can produce electricity.
The emitter’s job is to radiate the heat out beyond Earth’s atmosphere. But the atmosphere is transparent only to photons of certain wavelengths. Within the mid-infrared range, which is where heat radiation from typical earthbound objects is concentrated, the most applicable atmospheric transmission band is in the 8- to 13-micrometer-wavelength range.
Even some simple emitters send out heat radiation at these wavelengths. For example, if it’s insulated from ambient surroundings, black paint emits enough radiation within that band to cool a surface down by 10 ºC when exposed to the night sky.
In the wavelength range outside 8 to 13 mm, the atmosphere bounces back a substantial amount of radiation. During the daytime, solar radiation comes into the equation. More-advanced emitter designs aim to avoid the incoming radiation from the atmosphere and sunlight by ensuring that they absorb and emit only within the transparency window. The idea of using such a wavelength-selective emitter for radiative cooling dates back to the pioneering work of Claes-Göran Granqvist and collaborators in the 1980s. Just as an engineer designs a radio antenna with a specific shape and size to transmit over a certain wavelength in a certain direction, we can design an emitter using a library of materials, each with a specific shape and size, to adjust the wavelength band and direction for heat radiation. The better we do this, the more heat the emitter ejects into space and the colder the emitter can get.
Glass is a great material for an emitter. Its atomic vibrations couple strongly to radiation around the 10-μm wavelength, forcing the material to emit much of its heat radiation within the transmission window. Just touch a glass window at night and you’ll feel this cooling. Adding a metallic film to help reflect radiation skyward makes the emissions—and the cooling—even more effective. And structures can be specifically designed to strongly reflect the wavelengths of sunlight.
When an emitter radiates heat at a wavelength within the atmospheric transmission window, it cools down, creating a cold reservoir. A thermoelectric generator can then use the ambient air as its hot side and the emitter as its cold side to produce electricity. Chris Philpot
A decade ago, our research group created the first radiative cooling material that works in the daytime, efficiently cooling itself down below the ambient air temperature, even in direct sunlight. It’s constructed from alternating thin films of hafnium oxide (HfO2) and glass sitting on top of a silver reflective layer. By carefully selecting the thicknesses of each layer of film, we were able to make this material reflect solar radiation almost completely while simultaneously sending heat out through the atmospheric transmission window.
Since then, many other research groups have demonstrated various designs for daytime radiative cooling. One group of researchers at the University of Colorado, Boulder, designed an emitter by embedding a polymer film with microscopic glass beads and coating the back of it with a thin layer of silver. The glass beads send heat radiation out from the polymer while the silver coating reflects incoming sunlight.
As for our material, we have already commercialized one application: cooling structures without the use of electricity, thereby reducing or eliminating the need for building air-conditioning. SkyCool Systems, a spin-off from our research group, sells passive cooling panels that can be used as a stand-alone cooling system or as an add-on to existing air-conditioning and refrigeration systems. So far, SkyCool has installed panels at a number of grocery stores across the United States.
In a 2017 proof of concept, replicated in November 2023 [top], the emitter is a black-painted aluminum plate inside an insulation chamber whose plastic cover is transparent to mid-infrared radiation. A thermoelectric generator inserted in the bottom of the chamber uses the emitter as its cold source and the metal stand as its heat source to power an LED. In a later experiment [bottom], a solar cell serves as the emitter. During the daytime, the solar cell generates electricity from sunlight. At the same time, the thermoelectric generator produces extra electricity from the heat flowing between the solar cell and its colder surroundings. At night, the generator produces electricity from the opposite heat flow—between the hotter surroundings and the colder emitter.Photos: Sid Assawaworrarit/Stanford University
Energy harvesting using the cold of the universe is still under development. As our first proof of concept, we made a simple emitter using black paint on an aluminum plate. We enclosed the emitter in a foam box with a cover of transparent polyethylene film; this allowed the emitter to radiate heat into space while insulating it against heat from the surroundings.
We then cut a small hole in the bottom of the foam box and attached an off-the-shelf thermoelectric generator to the emitter (which you’ll recall also acts as a cold sink). For the hot side of our generator, we attached a heat sink that passively collected heat from the immediate surroundings.
To avoid having to contend with sunlight, we tested this setup at night, on the rooftop of Stanford’s David Packard Electrical Engineering Building. It generated 25 milliwatts of power per square meter of our emitter’s surface area and lit up an LED.
Our system resembled a solar panel, so we began to consider the possibilities of combining the two technologies for a device that generates power day and night. Commercial silicon solar cells typically have a top protective layer made of silica glass, which transmits a significant amount of heat radiation at the frequencies needed to traverse the atmosphere. Using that glass as the emitter, with a similar insulation setup as our first demonstration and a thermoelectric generator inserted between the glass and the solar cell, we demonstrated 50 milliwatts per square meter of nighttime electricity generation, without interrupting the photovoltaic’s daytime functioning.
While interesting, a 50 mW/m2 power density is of little practical use; even a suburban grocery store rooftop—say, about 4,000 m2—would yield just 200 watts, about enough to power a small refrigerator. We needed to increase the power density of our energy harvester to make it an attractive option for powering lighting and other low-power electronics at night. So we began testing modifications to our setup in a simulated model, discovering a number of ways to improve our design.
The key is optimizing the size of the thermoelectric generator for a given emitter area. A larger generator produces more power for a given degree of temperature difference between the emitter and the ambient surroundings, but it lowers the temperature difference that the emitter can sustain by permitting more heat to flow between the two. By getting the balance right, we demonstrated a doubling of power density to more than 100 mW/m2, using just the black-paint emitter.
Thermally insulating the emitter from its surroundings to allow it to reach a very cold temperature is also very important. Obviously, much better insulating materials are available than those used in our demo.
Finally, more spectrally selective emitters, like the glass-bead design and the multilayer hafnia design described, cool to much lower temperatures than black paint on aluminum, and therefore increase the power density.
Putting all these optimizations together, we calculated that the maximum achievable power density for this technology is 2.2 W/m2. This power density is a lot lower than what can be generated with solar cells under sunlight. However, when sunlight isn’t readily available, this is pretty good; it’s significantly higher compared to what can be achieved with many other ambient energy-harvesting schemes. For example, it’s orders of magnitude more than the less than 1 mW/m2 that can be harvested from ambient radio waves.
Our approach here hinges on using the emitter to both send out heat radiation to cold space and act as a local cold reservoir. That means we must insulate the emitter to prevent a constant intrusion of heat to maintain the temperature difference.
But what if we didn’t need that local temperature difference to generate electricity? To answer this question, we looked to solar photovoltaics, to determine if there is a cold analog that works with deep space instead of sunlight.
A photovoltaic cell can generate electricity from both the absorption and the emission of heat radiation. When the cell is exposed to heat radiation from a hotter body, a large number of electron-hole pairs form, and the cell develops a positive voltage potential. When the cell is exposed to a colder body, electrons and holes in the cell recombine into outgoing radiation, and the cell develops a negative voltage potential.Chris Philpot
In solar energy harvesting, a photovoltaic cell generates electricity directly from the sun’s radiation, thanks to what happens inside a semiconductor as it absorbs light. Recall that electrons and holes—the charge carriers in a semiconductor—normally exist in a minute quantity in an undoped semiconductor, as a result of thermal excitation at room temperature. But if you bombard the semiconductor with photons having energies greater than the bandgap of the semiconductor, you can generate many more electrons and holes. To separate the photogenerated electrons and holes, selective contacts—those that allow only one type of charge carrier to pass through—are attached to both sides of the semiconductor. A common way to do this is to dope one side of the semiconductor so that it’s p-type, which lets holes pass and blocks electrons, and the other side so that it’s n-type, which lets electrons pass and blocks holes. The result is an accumulation of holes on the p-side and electrons on the n-side, giving the p-side a positive voltage relative to the n-side; electrons flow from the n-side when a load is connected.
This familiar picture of photovoltaic operation assumes a relatively cold photovoltaic cell on Earth bathed in bright radiation coming from a much hotter body like the sun. The cold analogue is a photovoltaic cell on Earth facing the void of space. Here, Earth is hot compared to space, and the temperature difference means that the earthbound photovoltaic cell emits net radiation to space.
In such a case, the electrons and holes in the semiconductor recombine and radiate photons, reversing the process of light absorption. This recombination eats up the population of electrons and holes, pulling holes away from the p-side and electrons away from the n-side. With no incoming radiation to balance the radiative recombination, the depopulation of charges on both ends causes the p-side to develop a negative voltage relative to the n-side. Connect a load and electrons flow from the p-side. The voltage polarity is the opposite of the scenario in which a cold photovoltaic cell absorbs radiation from the hot sun—but it’s still electricity. This phenomenon of a solar cell generating energy when facing a cold object is not surprising; it is implied in the well-known Shockley-Queisser limit, which explains the maximum theoretical efficiency of a solar cell.
More recently, our research group and others studied the possibility of using such a device to harvest electricity from the heat radiation that Earth releases to the universe. We call this “negative” illumination for its net release of radiation, to distinguish it from the “positive” illumination that occurs in a solar cell. Some others call it thermoradiative energy harvesting.
To make negative illumination work for energy harvesting on Earth requires the photovoltaic cell to emit radiation at a wavelength within the atmospheric transmission window. In this window, the electrons and holes can recombine into outgoing radiation. Outside the window, the radiation bouncing back from the atmosphere destroys the process that creates that negative voltage. To hit that transmission window, we have to create the photovoltaic cell from a semiconductor with a tiny bandgap—around 0.09 electron volts—which corresponds to the edge of the transmission window at a wavelength of 13 μm.
That’s indeed possible, though not with silicon. In our first laboratory experiment, we used a mercury cadmium telluride (MCT) photovoltaic cell with a bandgap of around 0.1 eV. We confirmed the negative illumination effect by pointing the MCT cell at a temperature-controlled surface. The setup allowed us to heat up the surface to make it emit more radiation—allowing our MCT cell to operate under positive illumination—and then to cool down the surface, allowing the MCT cell to switch to negative illumination. By changing the temperature of the surface, we were able to observe the transition between positive illumination and negative illumination from the corresponding change in the cell’s voltage output.
We then took our MCT cell out of the lab and pointed it at the night sky to test the effect using the cold universe. We did generate electricity, but at a power density of just 64 nanowatts per square meter, much lower than that of our emitter-based approach.
A couple of things were to blame. First, the bandgap of the MCT cell is just a little too high to be in the ideal transmission window. Second, small bandgap semiconductors suffer greatly from nonradiative processes—that is, electron-hole recombinations that don’t emit radiation. Combined, these reduced the power our cell could deliver.
In an almost perfect world, in which we have discovered the best materials for emitters and negative-illumination photovoltaic cells and solved all our other design problems, we calculate that the maximum power density for the thermoelectric emitter system and the negative illumination approaches is around 5 W/m2. That’s about one-thirtieth what commercial solar cells deliver at peak sunlight or about the same as what a solar cell produces inside a brightly lit office.
In a more realistic scenario, we think we can reach a power density on the order of 1 W/m2. That may not sound like much, but it’s sufficient to power LED lighting and air-quality sensors, and keep smartphone batteries charged. In the long run, it’s perhaps not unreasonable to imagine living in a faraway cabin, off the grid, without batteries, using incoming and outgoing radiation from far beyond Earth’s atmosphere to heat, cool, and generate electricity day and night.
Reference: https://ift.tt/JNQADrcIn 2024, technologies to combat climate change soared above the clouds in electricity-generating kites, traveled the oceans sequestering...
