Most 3D printing methods currently in use rely either on photo (light)- or thermo (heat)-activated reactions to achieve precise manipulation of polymers. The development of a new platform technology called direct sound printing (DSP), which uses soundwaves to produce new objects, may offer a third option.
The process is described in a paper published in Nature Communications. It shows how focused ultrasound waves can be used to create sonochemical reactions in minuscule cavitation regions — essentially tiny bubbles. Extremes of temperature and pressure lasting trillionths of a second can generate pre-designed complex geometries that cannot be made with existing techniques.
“Ultrasonic frequencies are already being used in destructive procedures like laser ablation of tissues and tumours. We wanted to use them to create something,” says Muthukumaran Packirisamy, a professor and Concordia Research Chair in the Department of Mechanical, Industrial and Aerospace Engineering at the Gina Cody School of Engineering and Computer Science. He is the paper’s corresponding author.
Mohsen Habibi, a research associate at Concordia’s Optical-Bio Microsystems Lab, is the paper’s lead author. His lab colleague and PhD student Shervin Foroughi and former master’s student Vahid Karamzadeh are co-authors.
As the researchers explain, DSP relies on chemical reactions created by fluctuating pressure inside tiny bubbles suspended in a liquid polymer solution.
“We found that if we use a certain type of ultrasound with a certain frequency and power, we can create very local, very focused chemically reactive regions,” Habibi says. “Basically, the bubbles can be used as reactors to drive chemical reactions to transform liquid resin into solids or semi-solids.”
The reactions caused by ultrasound-wave-directed oscillation inside the micro-sized bubbles are intense, though they only last picoseconds. The temperature inside the cavity shoots up to around 15,000 Kelvin and pressure exceeds 1,000 bar (the Earth’s surface pressure at sea level is around one bar). The reaction time is so brief the surrounding material is not affected.
The researchers experimented on a polymer used in additive manufacturing called polydimethylsiloxane (PDMS). They used a transducer to generate an ultrasonic field that passes through the build material’s shell and solidifies the targeted liquid resin and deposits it onto a platform or another previously solidified object. The transducer moves along a predetermined path, eventually creating the desired product pixel by pixel. The microstructure’s parameters can be manipulated by adjusting the duration of the ultrasound wave’s frequency and the viscosity of the material being used.
Versatile and specific
The authors believe that DSP’s versatility will benefit industries that rely on highly specific and delicate equipment. The polymer PDMS, for instance, is widely used in the microfluidics industry, where manufacturers require controlled environments (cleanrooms) and sophisticated lithographic technique to create medical devices and biosensors.
Aerospace engineering and repair can also benefit from DSP, as ultrasound waves penetrate opaque surfaces like metallic shells. This can allow maintenance crews to service parts located deep within an aircraft’s fuselage that would be inaccessible to printing techniques reliant on photoactivated reactions. DSP could even have medical applications for remote in-body printing for humans and other animals.
“We proved that we can print multiple materials, including polymers and ceramics,” Packirisamy says. “We are going to try polymer-metal composites next, and eventually we want to get to printing metal using this method.”
The study received funding from ALIGO INNOVATION, Concordia and the Fonds de recherche du Québec — Nature et technologies (FRQNT).
Facial Recognition—Now for Seals – Hakai Magazine
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Have you ever looked at a seal and thought, Is that the same seal I saw yesterday? Well, there could soon be an app for that based on new seal facial recognition technology. Known as SealNet, this seal face-finding system was developed by a team of undergraduate students from Colgate University in New York.
Taking inspiration from other technology adapted for recognizing primates and bears, Krista Ingram, a biologist at Colgate University, led the students in developing software that uses deep learning and a convolutional neural network to tell one seal face from another. SealNet is tailored to identify the harbor seal, a species with a penchant for posing on coasts in haulouts.
The team had to train their software to identify seal faces. “I give it a photograph, it finds the face, [and] clips it to a standard size,” says Ingram. But then she and her students would manually identify the nose, the mouth, and the center of the eyes.
For the project, team members snapped more than 2,000 pictures of seals around Casco Bay, Maine, during a two-year period. They tested the software using 406 different seals and found that SealNet could correctly identify the seals’ faces 85 percent of the time. The team has since expanded its database to include around 1,500 seal faces. As the number of seals logged in the database goes up, so too should the accuracy of the identification, Ingram says.
As with all tech, however, SealNet is not infallible. The software saw seal faces in other body parts, vegetation, and even rocks. In one case, Ingram and her students did a double take at the uncanny resemblance between a rock and a seal face. “[The rock] did look like a seal face,” Ingram says. “The darker parts were about the same distance as the eyes … so you can understand why the software found a face.” Consequently, she says it’s always best to manually check that seal faces identified by the software belong to a real seal.
Like a weary seal hauling itself onto a beach for an involuntary photo shoot, the question of why this is all necessary raises itself. Ingram believes SealNet could be a useful, noninvasive tool for researchers.
Of the world’s pinnipeds—a group that includes seals, walruses, and sea lions—harbor seals are considered the most widely dispersed. Yet knowledge gaps do exist. Other techniques to track seals, such as tagging and aerial monitoring, have their limitations and can be highly invasive or expensive.
Ingram points to site fidelity as an aspect of seal behavior that SealNet could shed more light on. The team’s trials indicated that some harbor seals return to the same haulout sites year after year. Other seals, however, such as two animals the team nicknamed Clove and Petal, appeared at two different sites together. Increasing scientists’ understanding of how seals move around could strengthen arguments for protecting specific areas, says Anders Galatius, an ecologist at Aarhus University in Denmark who was not involved in the project.
Galatius, who is responsible for monitoring Denmark’s seal populations, says the software “shows a lot of promise.” If the identification rates are improved, it could be paired with another photo identification method that identifies seals by distinctive markings on their pelage, he says.
In the future, after further testing, Ingram hopes to develop an app based on SealNet. The app, she says, could possibly allow citizen scientists to contribute to logging seal faces. The program could also be adapted for other pinnipeds and possibly even for cetaceans.
NASA launches nanosatellite in preparation for lunar 'Gateway' station – Yahoo News Canada
Nasa has launched a tiny CubeSat this week to test and orbit which will soon be used by Gateway, a lunar space station.
It’s all part of the space agency’s plan to put a woman on the moon by 2025.
The Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (Capstone) mission launched from New Zealand on Tuesday.
Jim Reuter, associate administrator for the Space Technology Mission Directorate, said: “Capstone is an example of how working with commercial partners is key for Nasa’s ambitious plans to explore the moon and beyond.
“We’re thrilled with a successful start to the mission and looking forward to what Capstone will do once it arrives at the Moon.”
Read more: Astronomers find closest black hole to Earth
The satellite is currently in low-Earth orbit, and it will take the spacecraft about four months to reach its targeted lunar orbit.
Capstone is attached to Rocket Lab’s Lunar Photon, an interplanetary third stage that will send it on its way to deep space.
Over the next six days, Photon’s engine will periodically ignite to accelerate it beyond low-Earth orbit, where Photon will release the CubeSat on a trajectory to the moon.
Capstone will then use its own propulsion and the sun’s gravity to navigate the rest of the way to the Moon.
The gravity-driven track will dramatically reduce the amount of fuel the CubeSat needs to get to the Moon.
Read more: There might once have been life on the moon
Bradley Cheetham, principal investigator for CAPSTONE and chief executive officer of Advanced Space, “Our team is now preparing for separation and initial acquisition for the spacecraft in six days.
“We have already learned a tremendous amount getting to this point, and we are passionate about the importance of returning humans to the Moon, this time to stay!”
At the moon, Capstone will enter an elongated orbit called a near rectilinear halo orbit, or NRHO.
Once in the NRHO, Capstone will fly within 1,000 miles of the moon’s north pole on its near pass and 43,500 miles from the south pole at its farthest.
It will repeat the cycle every six-and-a-half days and maintain this orbit for at least six months to study dynamics.
“Capstone is a pathfinder in many ways, and it will demonstrate several technology capabilities during its mission timeframe while navigating a never-before-flown orbit around the Moon,” said Elwood Agasid, project manager for Capstone at Nasa’s Ames Research Center in California’s Silicon Valley.
“Capstone is laying a foundation for Artemis, Gateway, and commercial support for future lunar operations.”
It would be the first time people have walked on the moon since the last Apollo moon mission in 1972.
Just 12 people have walked on the moon – all men.
Nasa flew six manned missions to the surface of the moon, beginning with Neil Armstrong and Buzz Aldrin in July 1969, up to Gene Cernan and Jack Schmitt in December 1972.
The mission will use Nasa’s powerful new rocket, the Space Launch System (SLS), and the Orion spacecraft.
Watch: NASA launch paves way for moon orbit station
The year’s biggest and brightest supermoon will appear in July & here’s when you’ll … – Curiocity
Summer is here and with it? Sunshine – and some serious moonshine (of the visible variety, of course). This upcoming month, look up in anticipation of the biggest and brightest event of the year, the July Buck supermoon – which will hover over North America on July 13th.
Appearing 7% larger and lower in the sky, this particular event will be one well worth keeping an eye on when it rises above the horizon.
This will be the closest we’ll get to our celestial neighbour in 2022 (357,418 km) and while North America won’t get to see it when it reaches peak illumination at 2:38 pm ETC., it’ll still look pretty dang impressive after the sunsets.
Not sure when the moon rises in your area? Here’s the earliest that you’ll be able to see the moon in various cities across the continent according to the Farmer’s Almanac.
- Seattle, Washington – 9:50 pm PDT
- Vancouver, British Columbia – 10:02 pm PDT
- Calgary, Alberta – 10:35 pm MST
- Edmonton, Alberta – 10:49 pm MST
- Toronto, Ontario – 9:34 pm MST
- Montreal, Quebec – 9:18 pm MST
Until then, cross your fingers for a clear sky, friends! It’s going to be incredible.
When: Wednesday, July 13th
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