Show Notes 21 July 2023

Story 1: World’s Largest Nuclear Fusion Rocket Engine Begins Construction

Source: ScienceAlert.com Story by David Nield

Link: https://www.sciencealert.com/worlds-largest-nuclear-fusion-rocket-engine-begins-construction

See video here: https://www.youtube.com/watch?v=EIp60JwMLhI

• Nuclear fusion propulsion technology has the potential to revolutionize space travel in terms of both speeds and fuel usage. The same kinds of reactions that power the Sun could cut the travel time to Mars by half or make a journey to Saturn and its moons take just two years rather than eight.

• It’s incredibly exciting, but not everyone is convinced this is going to work: the tech needs ultra-high temperatures and pressures to function.

• To help prove the viability of the technology, Pulsar Fusion in the UK is building the largest ever fusion rocket engine.  ***watch the video that runs when you access their website!

• The chamber, some 8 meters (26 feet) long, is scheduled to start firing in 2027.

• As you might expect, replicating the Nuclear Fusion reactions that power the Sun and other stars inside a rocket isn’t easy. At the center of nuclear fusion propulsion is an ultra-hot plasma locked inside an electromagnetic field, and scientists are continuing to figure out how to do this in a stable and safe way.

• James Lambert, CFO of Pulsar Fusion notes, “The difficulty is learning how to hold and confine the super-hot plasma within an electromagnetic field. The plasma behaves like a weather system in terms of being incredibly hard to predict using conventional techniques.”

• According to the team at Pulsar Fusion, machine learning could help make this box of wild weather a little [more] easy to map. With this in mind Pulsar Fusion has partnered with Princeton Satellite Systems in the US to use supercomputer algorithms to better predict how the plasma is likely to behave, and how it might be more precisely controlled.

• Side note: Princeton Satellite Systems, Inc. is an aerospace research and development company. They are developing fusion microreactors for space and terrestrial power.

• If scientists are able to get everything functioning as intended, temperatures of several hundred million degrees will be reached in the chamber, making it hotter than the Sun. The surplus energy released could potentially drive rocket speeds of 500,000 miles (804,672 kilometers) per hour.

• The particular type of engine Pulsar Fusion is developing is a Direct Fusion Drive (DFD), in which the charged particles create thrust directly, rather than converting into electricity. It’s more efficient than other options, is powered by atomic isotopes, and doesn’t need a huge fuel payload.

• Side note – Atoms with the same number of protons but different numbers of neutrons are called isotopes.

Story 2: This ‘thermal cloak’ keeps spaces from getting either too hot or cold – The prototype fabric could one day help reduce heating and cooling energy cost

Source: ScienceNews.org Story by Skyler Ware

Link: https://www.sciencenews.org/article/thermal-cloak-material-temperature

• Researchers have created a prototype of a fabric which acts as a “thermal cloak” that keeps the space underneath it from getting too hot or too cold. The cloak does not require an external power source, which could reduce energy consumption associated with heating and cooling.

• In a new study, an engineer at Shanghai Jiao Tong University and colleagues made the cloak using two layers. The outer layer is made of white silica fibers that reflect visible light, coated with hexagonal boron nitride, a ceramic material that reflects ultraviolet light and helps dissipate heat. 

• Together, the silica fibers and boron nitride reflect 96 percent of the sunlight that hits the fabric. 

• At the same time, the outer layer absorbs heat from the surrounding area and emits that energy as infrared light, which also lowers the temperature under the cloak through a process called radiative cooling.

• The researchers tested the cloak material’s durability under several extreme conditions. They baked the fabric at 800° Celsius [1,472° Fahrenheit], just about hot enough to melt table salt. 

• The fabric was also subjected to other extreme tests, including:
  • They exposed it to extreme cold by dunking it in liquid nitrogen, 
  • subjected it to the same amount of vibration as a rocket launch, 
  • doused it in acid 
  • and blasted it with fire from a butane torch — all with virtually no changes to the material’s structure or performance. 

• This extreme durability might lend the material for use in spacecraft or extraterrestrial environments, the team says.

• To test the fabric the researchers built a full-size prototype cloak and tested it on an electric car. On a summer day in Shanghai, the cloak kept the car at about 23° C [73.4° Fahrenheit] — up to 8 degrees C [46.4° Fahrenheit] lower than the outside temperature and 28 degrees C [82.4° Fahrenheit] lower than the inside of an uncloaked car. The cloak also kept the car about 5 degrees C [41° Fahrenheit] warmer than the outside air on a winter night.

Story 3: This High-Tech Paint Could Cool the World

Source: Popular Mechanics Story by Jackie Appel [July 14, 2023]

Link: https://www.msn.com/en-us/weather/topstories/this-high-tech-paint-could-cool-the-world/ar-AA1dSeJM

Link: https://www.purdue.edu/newsroom/releases/2021/Q2/the-whitest-paint-is-here-and-its-the-coolest.-literally..html

• Note, this is a development first reported April 2021, but this past week has captured a lot of media attention – e.g. The Today Show on NBC did a segment on this a few days ago.  —  A team of researchers from Purdue University has developed the whitest paint on Earth, which reflects 98 percent of sunlight back out into space. 

• Reflecting a full 98% of sunlight can really have an impact—according to a press release, it can keep surfaces 8° Fahrenheit cooler than the air during the day, 19° Fahrenheit cooler than the air at night. 

• And, according to the New York Times, it can reduce the air conditioning needs of a building by up to 40 percent if painted on a roof. Reflecting light, keeping cool, and saving energy.

• Thanks to the way it’s engineered, it also won’t blind someone with eye-burning glare. The paint has a very high concentration of barium sulfate, a highly reflective material that is key to the cooling capabilities of this paint. 

• When engineering the paint, researchers incorporated barium sulfate in the form of particles of various sizes that encourage the light to scatter when it hits the surface, meaning it doesn’t just beam right back into your eyes and make it hard to see.

• Could this solve climate warming? Turns out all we may need to stop climate change is 139 billion gallons of super-duper white paint. See: https://www.msn.com/en-us/weather/topstories/turns-out-all-we-may-need-to-stop-climate-change-is-139-billion-gallons-of-super-duper-white-paint/ar-AA1dPrk8

• According to Jeremy Munday, a professor of electrical and computer engineering at the University of California, Davis, who researches clean technology, if a material like Purdue’s paint covered 1-2% of the Earth’s surface, the amount of light being bounced back into space would reduce the amount of heat being absorbed by the planet enough to stabilize global temperatures.

• But just how big is 1-2% of the Earth’s surface? The total surface area of the Earth is right around 197 million square miles (and most of that is water), so the paint would need to cover between approximately 2 million and 4 million square miles. For reference, the total land area of the United States is just over 3.5 million square miles, so we’d need to cover the country in white paint from sea to paint-stained sea.

Story 4: Unraveling connections between the brain and gut – MIT engineers’ new technology can probe the neural circuits that influence hunger, mood, and a variety of diseases.

Source: MIT News Story by Anne Trafton

Link: https://news.mit.edu/2023/unraveling-connections-between-brain-gut-0622

These flexible fibers, which are embedded with sensors and light sources, can be used to manipulate and monitor the connections between the brain and the digestive tract. Credits: Image: Courtesy of the researchers

Duke University postdoc Laura Rupprecht, MIT graduate student Atharva Sahasrabudhe, and MIT postdoc Sirma Orguc in the lab.

• The brain and the digestive tract are in constant communication, relaying signals that help to control feeding and other behaviors. This extensive communication network also influences our mental state and has been implicated in many neurological disorders.

• MIT engineers have designed a new technology for probing those connections. Using fibers embedded with a variety of sensors, as well as light sources for optogenetic stimulation, the researchers have shown that they can control neural circuits connecting the gut and the brain, in mice.

• Time out, what is optogenetic stimulation? Optogenetic stimulation is a genetic technique that enables scientists to activate or inhibit the activity of specific neuron populations using light. Source: https://www.mightexbio.com/optogenetic-stimulation/

• In a new study, the MIT researchers demonstrated that they could induce feelings of fullness or reward-seeking behavior in mice by manipulating cells of the intestine. 

• In future work, they hope to explore some of the correlations that have been observed between digestive health and neurological conditions such as autism and Parkinson’s disease.

• Here’s what one of the researchers had to say, “The exciting thing here is that we now have technology that can drive gut function and behaviors such as feeding. More importantly, we have the ability to start accessing the crosstalk between the gut and the brain with the millisecond precision of optogenetics….” 

• As part of the center’s work, the team set out to probe the signals that pass between the brain and the nervous system of the gut, also called the enteric nervous system. Sensory cells in the gut influence hunger and the feeling of fullness via both the neuronal communication and hormone release.

• Untangling those hormonal and neural effects has been difficult because there hasn’t been a good way to rapidly measure the neuronal signals, which occur within milliseconds.

• Side note – neuronal means relating to a neuron or neurons. And a neuron is a type of cell that receives and sends messages from the body to the brain and back to the body.

• As one of the researchers put it, “To be able to perform gut optogenetics and then measure the effects on brain function and behavior, which requires millisecond precision, we needed a device that didn’t exist. So, we decided to make it.”

• The electronic interface that the researchers designed consists of flexible fibers that can carry out a variety of functions and can be inserted into the organs of interest. To create the fibers the researchers used a technique called thermal drawing, which allowed them to create polymer filaments, about as thin as a human hair, that can be embedded with electrodes and temperature sensors.

• What is thermal drawing? The thermal drawing process consists in slowly inserting and heating a macroscopic polymer preform above its glass transition temperature and pulling it at a fixed speed to produce a continuous and uniform fiber. Source: https://onlinelibrary.wiley.com/doi/full/10.1002/smll.202101392

• The filaments also carry microscale light-emitting devices that can be used to optogenetically stimulate cells, and microfluidic channels that can be used to deliver drugs.

• The fibers are also designed so that they can be controlled wirelessly, using an external control circuit that can be temporarily affixed to the animal during an experiment. 

• Using this interface, the researchers performed a series of experiments to show that they could influence behavior through manipulation of the gut as well as the brain.

• The researchers now plan to use this interface to study neurological conditions that are believed to have a gut-brain connection. For instance, studies have shown that autistic children are far more likely than their peers to be diagnosed with gastrointestinal dysfunction, while anxiety and irritable bowel syndrome share genetic risks.

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