How light can vaporize water without the need for heat

Surprising “photomolecular effect” discovered by MIT researchers could affect calculations of climate change and may lead to improved desalination and drying processes.

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

 

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RESEARCHERS AT MIT HAVE DISCOVERED A NEW PHENOMENON: THAT LIGHT CAN CAUSE EVAPORATION OF WATER FROM ITS SURFACE WITHOUT THE NEED FOR HEAT. PICTURED IS A LAB DEVICE DESIGNED TO MEASURE THE “PHOTOMOLECULAR EFFECT,” USING LASER BEAMS.

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CREDIT: BRYCE VICKMARK

It’s the most fundamental of processes — the evaporation of water from the surfaces of oceans and lakes, the burning off of fog in the morning sun, and the drying of briny ponds that leaves solid salt behind. Evaporation is all around us, and humans have been observing it and making use of it for as long as we have existed. 

And yet, it turns out, we’ve been missing a major part of the picture all along.

In a series of painstakingly precise experiments, a team of researchers at MIT has demonstrated that heat isn’t alone in causing water to evaporate. Light, striking the water’s surface where air and water meet, can break water molecules away and float them into the air, causing evaporation in the absence of any source of heat.

The astonishing new discovery could have a wide range of significant implications. It could help explain mysterious measurements over the years of how sunlight affects clouds, and therefore affect calculations of the effects of climate change on cloud cover and precipitation. It could also lead to new ways of designing industrial processes such as solar-powered desalination or drying of materials.

The findings, and the many different lines of evidence that demonstrate the reality of the phenomenon and the details of how it works, are described in the journal PNAS, in a paper by Carl Richard Soderberg Professor of Power Engineering Gang Chen, postdocs Guangxin Lv and Yaodong Tu, and graduate student James Zhang.

The authors say their study suggests that the effect should happen widely in nature— everywhere from clouds to fogs to the surfaces of oceans, soils, and plants — and that it could also lead to new practical applications, including in energy and clean water production. “I think this has a lot of applications,” Chen says. “We’re exploring all these different directions. And of course, it also affects the basic science, like the effects of clouds on climate, because clouds are the most uncertain aspect of climate models.” 

A newfound phenomenon

The new work builds on research reported last year, which described this new “photomolecular effect” but only under very specialized conditions: on the surface of specially prepared hydrogels soaked with water. In the new study, the researchers demonstrate that the hydrogel is not necessary for the process; it occurs at any water surface exposed to light, whether it’s a flat surface like a body of water or a curved surface like a droplet of cloud vapor.

Because the effect was so unexpected, the team worked to prove its existence with as many different lines of evidence as possible. In this study, they report 14 different kinds of tests and measurements they carried out to establish that water was indeed evaporating — that is, molecules of water were being knocked loose from the water’s surface and wafted into the air — due to the light alone, not by heat, which was long assumed to be the only mechanism involved.

One key indicator, which showed up consistently in four different kinds of experiments under different conditions, was that as the water began to evaporate from a test container under visible light, the air temperature measured above the water’s surface cooled down and then leveled off, showing that thermal energy was not the driving force behind the effect.

Other key indicators that showed up included the way the evaporation effect varied depending on the angle of the light, the exact color of the light, and its polarization. None of these varying characteristics should happen because at these wavelengths, water hardly absorbs light at all — and yet the researchers observed them.

The effect is strongest when light hits the water surface at an angle of 45 degrees. It is also strongest with a certain type of polarization, called transverse magnetic polarization. And it peaks in green light — which, oddly, is the color for which water is most transparent and thus interacts the least.

Chen and his co-researchers have proposed a physical mechanism that can explain the angle and polarization dependence of the effect, showing that the photons of light can impart a net force on water molecules at the water surface that is sufficient to knock them loose from the body of water. But they cannot yet account for the color dependence, which they say will require further study.

They have named this the photomolecular effect, by analogy with the photoelectric effect that was discovered by Heinrich Hertz in 1887 and finally explained by Albert Einstein in 1905. That effect was one of the first demonstrations that light also has particle characteristics, which had major implications in physics and led to a wide variety of applications, including LEDs. Just as the photoelectric effect liberates electrons from atoms in a material in response to being hit by a photon of light, the photomolecular effect shows that photons can liberate entire molecules from a liquid surface, the researchers say.

“The finding of evaporation caused by light instead of heat provides new disruptive knowledge of light-water interaction,” says Xiulin Ruan, professor of mechanical engineering at Purdue University, who was not involved in the study. “It could help us gain new understanding of how sunlight interacts with cloud, fog, oceans, and other natural water bodies to affect weather and climate. It has significant potential practical applications such as high-performance water desalination driven by solar energy. This research is among the rare group of truly revolutionary discoveries which are not widely accepted by the community right away but take time, sometimes a long time, to be confirmed.”

Solving a cloud conundrum

The finding may solve an 80-year-old mystery in climate science. Measurements of how clouds absorb sunlight have often shown that they are absorbing more sunlight than conventional physics dictates possible. The additional evaporation caused by this effect could account for the longstanding discrepancy, which has been a subject of dispute since such measurements are difficult to make.

“Those experiments are based on satellite data and flight data,“ Chen explains. “They fly an airplane on top of and below the clouds, and there are also data based on the ocean temperature and radiation balance. And they all conclude that there is more absorption by clouds than theory could calculate. However, due to the complexity of clouds and the difficulties of making such measurements, researchers have been debating whether such discrepancies are real or not. And what we discovered suggests that hey, there’s another mechanism for cloud absorption, which was not accounted for, and this mechanism might explain the discrepancies.”

Chen says he recently spoke about the phenomenon at an American Physical Society conference, and one physicist there who studies clouds and climate said they had never thought about this possibility, which could affect calculations of the complex effects of clouds on climate. The team conducted experiments using LEDs shining on an artificial cloud chamber, and they observed heating of the fog, which was not supposed to happen since water does not absorb in the visible spectrum. “Such heating can be explained based on the photomolecular effect more easily,” he says.

Lv says that of the many lines of evidence, “the flat region in the air-side temperature distribution above hot water will be the easiest for people to reproduce.” That temperature profile “is a signature” that demonstrates the effect clearly, he says.

Zhang adds: “It is quite hard to explain how this kind of flat temperature profile comes about without invoking some other mechanism” beyond the accepted theories of thermal evaporation. “It ties together what a whole lot of people are reporting in their solar desalination devices,” which again show evaporation rates that cannot be explained by the thermal input.

The effect can be substantial. Under the optimum conditions of color, angle, and polarization, Lv says, “the evaporation rate is four times the thermal limit.”

Already, since publication of the first paper, the team has been approached by companies that hope to harness the effect, Chen says, including for evaporating syrup and drying paper in a paper mill. The likeliest first applications will come in the areas of solar desalinization systems or other industrial drying processes, he says. “Drying consumes 20 percent of all industrial energy usage,” he points out.

Because the effect is so new and unexpected, Chen says, “This phenomenon should be very general, and our experiment is really just the beginning.” The experiments needed to demonstrate and quantify the effect are very time-consuming. “There are many variables, from understanding water itself, to extending to other materials, other liquids and even solids,” he says.

The work was partly supported by an MIT Bose Award. 

“We’re exploring all these different directions,” Chen says. “And of course it also affects the basic science, like the effects of clouds on climate, because clouds are the most uncertain aspect of climate models.”

CREDIT

Bryce Vickmark

Written by David L. Chandler, MIT News

Paper: “Photomolecular effect: visible light interaction with air-water interface”

https://www.pnas.org/doi/10.1073/pnas.2320844121

---

JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2320844121 

ARTICLE TITLE

“Photomolecular effect: visible light interaction with air-water interface”

 

Bringing bio-inspired robots to life

Nebraska researcher Eric Markvicka gets NSF CAREER Award to pursue manufacture of novel materials for soft robotics and stretchable electronics

UNIVERSITY OF NEBRASKA-LINCOLN

 

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ERIC MARKVICKA (LEFT), ASSISTANT PROFESSOR OF MECHANICAL AND MATERIALS ENGINEERING, HOLDS A TRAY OF LIQUID METAL SAMPLES WHILE GRADUATE STUDENT ETHAN KRINGS WORKS ON A SAMPLE AT RIGHT. MARKVICKA HAS RECEIVED A CAREER AWARD FROM THE NATIONAL SCIENCE FOUNDATION TO ADVANCE HIS WORK WITH ROOM-TEMPERATURE, NON-TOXIC LIQUID METALS. 

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CREDIT: CRAIG CHANDLER/UNIVERSITY COMMUNICATION AND MARKETING/UNIVERSITY OF NEBRASKA-LINCOLN

Engineers are increasingly eager to develop robots that mimic the behavior of animals and biological organisms, whose adaptability, resilience and efficiency have been refined over millions of years of evolution.

In bringing bio-inspired robots to life, scientists must first create soft matter counterparts that match the softness and functionality of biological tissue. University of Nebraska–Lincoln engineer Eric Markvicka is at the forefront of these efforts. He recently received a five-year, $690,000 grant from the National Science Foundation’s Faculty Early Career Development Program to advance work on a manufacturing approach that would produce a novel class of materials that could propel the fields of soft robotics, stretchable electronics and beyond.

It would be the first manufacturing strategy to yield stable mixtures of liquid metals with a wide range of solid particle additives to achieve enhanced properties — including thermal and electrical conductivity, fluidity and capacity for self-repair — that exceed anything on today’s market.

The composites would be suitable for use in additive manufacturing, commonly known as 3D printing, and would accelerate momentum toward 4D printing, which produces machines that can morph to adapt to different environments.

“At the end of this project, we’ll have a manufacturing strategy for creating diverse liquid metal mixtures that are appropriate for additive manufacturing,” said Markvicka, assistant professor of mechanical and materials engineering. “Such capabilities will enable the engineering of new materials for hybrid 4D additive manufacturing where we can create a number of things, from robotics to machines, that ultimately mimic biological organisms.”

Scientists have long recognized the commercial potential of liquid metals, which offer infinite mechanical failure strain and enhanced thermal and electrical conductivity compared to other elastomers or fluids. They also have the ability to repair themselves, similar to many natural organisms: Markvicka’s previous work shows that electrical circuits formed by liquid metal droplets can reconfigure after damage occurs.

Graduate student Ethan Krings holds a sample of room-temperature, non-toxic liquid metals. 

CREDIT

Craig Chandler/University Communication and Marketing/University of Nebraska-Lincoln

To further enhance these properties, researchers have tried adding solid particles to liquid metals. But these efforts have run up against two major barriers. For one, most liquid metal varieties include gallium, one of the most highly reactive metals on the periodic table. Many additives, such as copper or aluminum, react with gallium in a way that transforms the mixture from a liquid to a solid, compromising the fluidic advantage.

When the additive doesn’t react with gallium, a different problem arises. The solid particles are enveloped in a thin oxide layer created by the liquid metal’s high surface tension. That layer allows the particles to be incorporated into the metal — but in the process, air voids form. These voids expand at higher temperatures, reducing the material’s thermal conductivity.

Markvicka’s strategy takes aim at both problems by adding an intermediate layer, or coating, to the additive particles. This nanoscale layer serves a dual purpose: For particles that would alloy, or mix, with gallium, it acts as a corrosion barrier, thwarting the reaction that would mitigate fluidity. For nonalloying particles, the layer acts as a wetting agent, enabling the material to integrate into the liquid metal without forming air voids.

Markvicka is one of just a handful of researchers nationwide who are exploring the use of coatings in liquid metal mixtures. If successful, the approach would enable engineers to make custom liquid metal mixtures with particular physical, chemical and rheological traits.

“Few have taken this interfacial engineering approach to not only protect the filler, in terms of the corrosion barrier that’s incorporated, but also develop the ability to take particles that don’t reactively wet and incorporate them,” he said.

Markvicka will also advance a new frontier in engineering education by emphasizing not just the technical side of the field, but also the business dimension. This “entrepreneering” approach merges entrepreneurial literacy with research-based education.

“We provide a mix of foundational and specialized technical courses; however, we rarely discuss economic impact or market viability when designing or creating new products,” he said. “In the rapidly changing job market, engineers who understand the entrepreneurial process are better positioned to seize opportunities and succeed in uncertain and complex situations.”

In concert with Nebraska’s Established Program to Stimulate Competitive Research, Markvicka will develop the first mobile science lab on manufacturing, which will integrate concepts from his research and entrepreneurial skills. It will be distributed to middle and high school students across Nebraska. Markvicka will collaborate with middle school teachers to help them incorporate the mobile lab into their classrooms.

On campus, Markvicka will integrate entrepreneering-based modules into traditional engineering courses, ensuring that a broader range of students are exposed to entrepreneurship principles.

“This isn’t just for people who are interested in starting a company or working for a startup,” he said. “These skills are also important for people working in industry. They need to know how you begin to vet and understand if an idea is viable commercially.”

The National Science Foundation’s CAREER award supports pre-tenure faculty who exemplify the role of teacher-scholars through outstanding research, excellent education and the integration of education and research.

Boston cannabis dispensary opens its doors on 4/20, adds to growing industry

Daniel Coates
Sun, April 21, 2024 

On the unofficial holiday of 4/20, another dispensary opened its doors to new customers – part of the booming statewide cannabis industry.

Rebelle on Albany Street in Boston is the first dispensary to open in the South End neighborhood. The company produces its own marijuana products while also selling other brands as well.

Guillermo Erazo, assistant general manager of the store, told Boston 25 that their natural products focus on general wellness.

“We produce our own product,” said Erazo. “We cultivate our own flower. We cultivate our own edibles and concentrates as well too.”

Rebelle is now one of more than a dozen dispensaries across Boston that sell recreational marijuana.

Recreational marijuana was legalized in Massachusetts in 2016. The cannabis control commission reported roughly $1.5 billion in sales in 2023 as the industry grows statewide.

Erazo added, “We have a lot of consumers who came down that are more happy that it’s recreational, that we open up doors for consumers to get it the correct way.”

The growing industry is also opening new doors for local businesses.

Sam Burgess of Bootstrap Compost in Everett held a pop-up at the South End dispensary, saying his company can create a more sustainable marijuana industry.

“We can actually compost green material after the harvesting,” said Burgess. “We can create bioplastics and whatnot for better packaging. So, I think there’s a lot of room for improvement.”

While dozens trickled into the store, Erazo told Boston 25 he hopes cannabis will soon be totally destigmatized.

Citing some benefits, Erazo finished, “Lupis, muscle relaxation, or an increase in appetite too.”

Since retail stores opened in 2018, the cannabis control commission has reported roughly $6 billion in sales

4/20 is the busiest time of year for Florida’s medical marijuana dispensaries

Ivy Nyayieka, Tampa Bay Times
Sat, April 20, 2024



It’s April 20 (or 4/20) — the unofficial holiday celebrating marijuana.

And if history is any indicator, it’s a great day for sales at Florida’s medical pot dispensaries.

In the past two years, Floridians with medical marijuana cards bought more weed during the week of 4/20 than any other week of the year. That’s according to a Times analysis of cannabis dispensary data from the state’s Office of Medical Marijuana Use. (420 is slang for pot smoking; its origins are debated.)

Steve Mazeika, the vice president of communications at Verano, the parent company of cannabis dispensary chain Müv, called April 20 “the cannabis community’s biggest annual holiday.”

Cannabis market research firm BDSA, which is based in Colorado, said in an email that the higher sales are likely due to “the overall hype surrounding the holiday” as well as increased marketing that cannabis dispensaries do around this time of year. It said revenues reached $23.26 million in Florida on April 20 last year.

“Despite being a medical market, the use of cannabis in Florida for relaxation and recreation-adjacent purposes is significant,” said BDSA chief executive officer Roy Bingham.

Florida only allows weed use for those with medical marijuana cards. But voters in November will decide on a proposed constitutional amendment that would allow recreational marijuana for adults in the state.

In 2023, nearly 440 million mg of medical marijuana was dispensed during the week of April 20, a 31% increase compared to 2022, according to state data.

The state saw a 14% growth in the number of medical marijuana patients in that period.

Florida’s not alone. Other states, including Arkansas and Colorado, have in the past reported bumps in medical marijuana sales around April 20, according to news reports.

420 fest draws crowds for cannabis celebration in Chaparral, New Mexico

Corrie Boudreaux
Sun, April 21, 2024 

Several hundred people gathered at an empty lot between two tiny strip malls along County Line Road in Chaparral, New Mexico, for a 420 celebration.

GT 420 Music Fest, organized by James and Christina Perez, owners of GT Dispensary in Chaparral, featured an all-day lineup of bands in English and Spanish and finished with an appearance by California hip-hop rap artist Lil Rob.


Hip-hop and rap artist Lil Rob entertain spectators on Saturday at the GT 420 Music Fest in Chaparral, New Mexico.


Though one myth has it that 420, 4/20 or 4:20 originates from a police code for marijuana, the true story is that a group of teenagers in 1970s California used “4:20” to allude to the time when they would meet after school to smoke. The term spread after it was used on a flyer distributed at a Grateful Dead concert in the early 90s, USA TODAY reported. Now, April 20 is known worldwide as a day to celebrate all things cannabis-related.

The dispensary owners wanted to give back to the community, so they decided to organize the free family-friendly event, they said.

James Perez, organizer of the GT 420 Music Fest in Chaparral, N.M., speaks to the crowd of spectators on April 20, 2024. The free event was organized by James and his wife, Christina Perez, owner of GT Dispensary, because they want to educate the public on the myriad uses of cannabis.

The introduction of New Mexico's cannabis industry to El Paso has facilitated easy access to legal cannabis, and dispensaries consistently attract a significant share of their customers from nearby El Paso.

James Perez uses it for medicinal purposes, but in the past, he had to travel from Chaparral to Las Cruces or Sunland Park to buy it. He and his wife decided to open their own dispensary in 2022 to provide marijuana for their community.

James Perez said that he and his wife want to prove that cannabis is far more useful than the popular stereotype of its recreational use might suggest.

Vintage cars are part of the show as spectators enjoy music, food, and cannabis-themed merchandise at the GT 420 Music Fest in Chaparral, New Mexico, on Saturday, April 20.

“Cannabis is a blessing because it’s medication,” Perez said. “We have customers in wheelchairs, customers with cancer. It can do so much for the body. I’d love for people to see it as medication.”

El Paso law enforcement, however, continues to enforce Texas marijuana laws. Both the city of El Paso and El Paso County have created programs to issue citations for people caught with low-level possession of marijuana. The citations can carry a hefty $500 fine.

Spectators enjoy music, food, and cannabis-themed merchandise at the GT 420 Music Fest in Chaparral, New Mexico.

Hip-hop rap artist Lil Rob performs at the GT 420 Music Fest on Saturday, April 20, in Chaparral, New Mexico.

This article originally appeared on El Paso Times: 420 fest draws crowds for cannabis celebration in New Mexico

Cherokee Street transforms for St. Louis’ annual 420 bash

Liz Dowell
Fri, April 19, 2024 


ST. LOUIS — This weekend marks a special celebration for cannabis enthusiasts. April 20th, known as “420,” has its roots in the 1970s as a term for cannabis consumption. It was coined by a group of school friends who regularly convened at 4:20 to partake in smoking sessions.

Over the years, the term has evolved into a cultural phenomenon, especially as cannabis legalization has taken hold in states like Missouri and its neighboring state, Illinois. As Missouri enters its second year of cannabis legality, St. Louis gears up to commemorate 420 with a series of city-wide events.

The festivities kick off with the Green Light District Festival on April 19th, running from 8 p.m. to 10 p.m. at the Cola Private Lounge on Cherokee Street. The opening act features a comedy show with food available for purchase. On April 20th and 21st, starting at noon, Cherokee Street will transform into a bustling hub of activity with a street crawl parade, vendors, live music, and more.

The mystery of the Des Peres Pickle Jar

Other celebrations in the area:

On 4/20, Steve’s Hotdogs will join the celebration with their Delta-9 THC-infused menu items during an event titled Steve’s 420: All Day Haze, running from 11 a.m. to 11 p.m.


The Loop 420 Street Fest returns for its second year, starting at 11 a.m. and running until 7 p.m. The event promises live music, glass blowing demonstrations, vendor booths, and much more.


The 4:20 STL Festival, held from 11 a.m. to 5 p.m., boasts 30 cannabis vendors, games, live performances, and prizes for the first 100 attendees.


Taking place inside a movie theater, “Sesh at the Cinema” features 420-themed vendors, live entertainment, a smoke box, and giveaways from 1 to 6 p.m.


On April 21st, The Factory will host its 420 celebration, screening “The Big Lebowski” starting at 3:30 p.m. The event will also feature pop-ups from Missouri cannabis companies showcasing their products, along with a costume contest.


For those seeking an outdoor experience, the Lit ‘N’ Lost Cannabash 4/20 will take place at Lost Hill Lake in Saint Clair, MO. Attendees can enjoy games, live music, smoke sessions, vendor booths, and food trucks.




North Country welcomes first 4/20 celebrations at recreational cannabis dispensaries

Can I be fired for smoking weed in off-hours? Grow cannabis at home? California laws to know

Sarah Linn
Sat, April 20, 2024 

Saturday marks a special holiday for fans of cannabis culture.

April 20, known as 4/20, is celebrated by marijuana enthusiasts across the globe.

Although cannabis use is legal in California, there are a number of laws in the Golden State governing how it can be cultivated and consumed.

Here’s a roundup of our latest cannabis-related coverage:

A man takes a picture of one the cannabis plants on display at the first Cannabis Awards and Exhibit at the California State Fair during media day on Wednesday, July 13, 2022. Hector Amezcua/hamezcua@sacbee.com
Can I grow cannabis at home?

Passed by California voters in 2016, the Adult Use of Marijuana Act allows adults 21 and older to legally grow, possess and use cannabis for recreational use.

You can grow up to six plants at your California residence for personal use only.

Plus, those cultivating cannabis at home can’t use volatile solvents — butane or propane — to process it, according to the California Department of Cannabis Control.

Breaking the rules about residential cannabis cultivation can result in a fine or imprisonment.

READ MORE:

Want to grow weed in your California home? Don’t break the law — but follow these tips
Can I get fired for smoking weed in my off-hours?

California Gov. Gavin Newsom signed Assembly Bill 2188 into law in 2022, banning employers from firing, penalizing or creating employment conditions for workers based on cannabis use off the job or away from the workplace.

The law went into effect on Jan. 1.

However, it only applies to some jobs.

READ MORE:

Can I be fired for smoking weed in my off-hours? What new California cannabis law says

Aaron Grove, right, owner of Elk Grove CBD, helps customer Ray Tamayo on Saturday, April 13, 2024. Elk Grove prohibits marijuana dispensaries from operating in the city limits. Lezlie Sterling/lsterling@sacbee.com

Marijuana sales are prohibited in Elk Grove. Would the city ever reconsider?
What’s the difference between edible cannabis and smoking weed?

Smoking marijuana and consuming cannabis-laced edibles can both lift your mood, but there are some key differences between the two.

Smoked or vaped marijuana enters the lungs and is absorbed into the bloodstream, according to cannabis education site Leafly, while edibles are processed in the stomach and liver.

That means edibles feel stronger and the effects will last a lot longer.

Smoking weed and ingesting cannabis also have varying effects on your health.

READ MORE:

Edible cannabis vs smoking weed: How are they different and what are the health effects?

Chandler Hale, a manager at All about Wellness in Sacramento holds some of the cannabis-infused edible gummies and fruit chews Tuesday, March 22, 2022. Hector Amezcua/hamezcua@sacbee.com

Cooking with cannabis? How edibles have changed

Since California legalized the recreational sale and use of cannabis, marijuana-infused food has become more creative and accessible.

Sacramento dispensaries sell everything from cannabis-injused hot sauce and buffalo jerky to weed lollipops, dulce de leche truffle bars and dark chocolate mocha malt balls.

Meanwhile, major beer brands such as Pabst, Lagunitas and Anheuser Busch-InBev offer flavored seltzers that are alcohol-free but include THC.

You can even cook with gourmet food with cannabis, experts say.

READ MORE:

Cooking with cannabis: How marijuana food edibles in Sacramento went to the next level

 

Researchers uncover ways to improve railcar roller bearing safety, strength

by Karl Vogel, University of Nebraska-Lincoln

A blue Brenco railcar axle bearing is shown on a railcar. Each railcar has more

 than 350 bearings to support the load and keep the wheels turning. This railcar

 was photographed in the Omaha, Lincoln and Beatirce Railway yard with 

permission from the railway. 

Credit: Craig Chandler | University Communication and Marketing

When Nebraska Engineering researchers began cooking up new recipes for manufacturing railcar bearing components, they expected there would be a few offerings that wouldn't be as satisfying.

However, rollers for a railroad tapered roller bearing produced using metal powders, a state-of-the-art 3D printing lab, and additive manufacturing processes proved to be just as robust as rollers made using currently conventional techniques.

Joseph Turner, Robert W. Brightfelt Professor of Mechanical Engineering, said the first-ever 3D-printed rollers for railroad bearings exceeded expectations, creating a starting point for expanding the use of this innovative process that could help to make transportation even safer. Their results were compiled into a paper—"Fatigue Performance of Bearing Rollers Manufactured by Laser Powder Bed Fusion"—that was published in Bearing and Transmission Steels Technology.

"We cooked up many different recipes and we printed many rollers," Turner said. "We expected the printed rollers to show failure early on in the tests, but the bottom line is they performed just as well as conventional rollers. Now, we're going to explore other ideas using this work as the foundation."

The team was led by Turner and recent mechanical engineering doctoral graduate Luz Sotelo. It also included former faculty member Michael Sealy, graduate students Cody Pratt, Guru Madireddy and Rakeshkumar Karunakaran, and industry partner Amsted Rail Brenco. The project also received support from the National Science Foundation and the Federal Railroad Administration. Sotelo was an NSF Graduate Fellow.

Turner said the team expected standard fatigue tests simulating the loads—up to 286,000 pounds per railcar over 250,000 miles traveled—would show the metal AM recipe for a printed bearing was in need of tweaking.

However, Turner said, the rollers printed in the College of Engineering's Nebraska Engineering Additive Technology Labs using 8620HC—a high-carbon steel—performed as well as those manufactured using current standard processes.

"Basically, when you look at the two types of rollers side by side, you can't see any difference in the look or their performance," Turner said. "A lot of times (in metal AM), you will have concerns about the porosity or the internal microstructure of the metals in the first printed objects. Our 3D-printed rollers held up to the demands of the loads and distance that are expected from the mass-produced bearings."

Typical railcar bearings have more than 40 rollers, which measure about 2 inches by ¾ of an inch, one bearing for each wheel, and a total of about 350 per railcar. The standard-use bearings, Turner said, are manufactured by cutting long loops of thick, steel wire into the required lengths and then grinding them down to create the tapers needed for optimal performance.

Using 3D printing to produce the rollers proved to be significantly more expensive than the current methods, Turner said. Despite that drawback, he said, the use of 3D printing could in the not-too-distant future find a place in many industries that use these types of bearings.

"You have to explore whether it's even possible before you can begin figuring out when it's cost effective," Turner said. "Setting up a production line that makes the bearings is a huge investment but, maybe, it can work in emergency situations—like a mining company in the outback of Australia has a failure that might otherwise hurt their ability to move their product. If they can 3D print a part and not have to wait for something to be shipped to them."

The next steps, Turner said, might also include looking at possible other ways to make 3D printing more financially sensible in the manufacturing process, such as using more expensive steel powders to create a coating on bearing components made from less expensive metals, to create an overall cheaper and more sturdy bearing with better properties.

"One of the things we in the NEAT Lab have become pretty proficient at is developing these new recipes for alloys," Turner said. "As prices for our ingredients and equipment continue to drop in price, we will be able to try rolling out some new things that could appeal to a lot of fields and industries."

More information: Luz D. Sotelo et al, Fatigue Performance of Bearing Rollers Manufactured by Laser Powder Bed Fusion, Bearing and Transmission Steels Technology (2024). DOI: 10.1520/STP164920220115

Provided by University of Nebraska-Lincoln Scientists propose anti-fatigue preparation for 3D-printed titanium alloy

With inspiration from “Tetris,” MIT researchers develop a better radiation detector

The device, based on simple tetromino shapes, could determine the direction and distance of a radiation source, with fewer detector pixels

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

The spread of radioactive isotopes from the Fukushima Daiichi Nuclear Power Plant in Japan in 2011 and the ongoing threat of a possible release of radiation from the Zaporizhzhia nuclear complex in the Ukrainian war zone have underscored the need for effective and reliable ways of detecting and monitoring radioactive isotopes. Less dramatically, everyday operations of nuclear reactors, mining and processing of uranium into fuel rods, and the disposal of spent nuclear fuel also require monitoring of radioisotope release. 

Now, researchers at MIT and the Lawrence Berkeley National Laboratory (LBNL) have come up with a computational basis for designing very simple, streamlined versions of sensor setups that can pinpoint the direction of a distributed source of radiation. They also demonstrated that by moving that sensor around to get multiple readings, they can pinpoint the physical location of the source. The inspiration for their clever innovation came from a surprising source: the popular computer game “Tetris.”

The team’s findings, which could likely be generalized to detectors for other kinds of radiation, are described in a paper published in Nature Communications, by MIT professors Mingda Li, Lin-Wen Hu, Benoit Forget, and Gordon Kohse; graduate students Ryotaro Okabe and Shangjie Xue; research scientist Jayson Vavrek SM ’16, PhD ’19 at LBNL; and a number of others at MIT and Lawrence Berkeley. 

Radiation is usually detected using semiconductor materials, such as cadmium zinc telluride, that produce an electrical response when struck by high-energy radiation such as gamma rays. But because radiation penetrates so readily through matter, it’s difficult to determine the direction that signal came from with simple counting. Geiger counters, for example, simply provide a click sound when receiving radiation, without resolving the energy or type, so finding a source requires moving around to try to find the maximum sound, similarly to how handheld metal detectors work. The process requires the user to move closer to the source of radiation, which can add risk. 

To provide directional information from a stationary device without getting too close, researchers use an array of detector grids along with another grid called a mask, which imprints a pattern on the array that differs depending on the direction of the source. An algorithm interprets the different timings and intensities of signals received by each separate detector or pixel. This often leads to a complex design of detectors.  

Typical detector arrays for sensing the direction of radiation sources are large and expensive and include at least 100 pixels in a 10 by 10 array. However, the group found that using as few as four pixels arranged in the tetromino shapes of the figures in the “Tetris” game can come close to matching the accuracy of the large, expensive systems. The key is proper computerized reconstruction of the angles of arrival of the rays, based on the times each sensor detects the signal and the relative intensity each one detects, as reconstructed through an AI-guided study of simulated systems.

Of the different configurations of four pixels the researchers tried — square, or S-, J- or T-shaped — they found through repeated experiments that the most precise results were provided by the S-shaped array. This array gave directional readings that were accurate to within about 1 degree, but all three of the irregular shapes performed better than the square. This approach, Li says, “was literally inspired by ‘Tetris.’”

Key to making the system work is placing an insulating material such as a lead sheet between the pixels to increase the contrast between radiation readings coming into the detector from different directions. The lead between the pixels in these simplified arrays serves the same function as the more elaborate shadow masks used in the larger-array systems. Less symmetrical arrangements, the team found, provide more useful information from a small array, explains Okabe, who is the lead author of the work. 

“The merit of using a small detector is in terms of engineering costs,” he says. Not only are the individual detector elements expensive, typically made of cadmium-zinc-telluride, or CZT, but all of the interconnections carrying information from those pixels also become much more complex. “The smaller and simpler the detector is, the better it is in terms of applications,” adds Li. 

While there have been other versions of simplified arrays for radiation detection, many are only effective if the radiation is coming from a single localized source. They can be confused by multiple sources or those that are spread out in space, while the “Tetris”-based version can handle these situations well, adds Xue, co-lead author of the work.

In a single-blind field test at the Berkeley Lab with a real cesium radiation source, led by Vavrek, where the researchers at MIT did not know the ground-truth source location, a test device was performed with high accuracy in finding the direction and distance to the source.  

“Radiation mapping is of utmost importance to the nuclear industry, as it can help rapidly locate sources of radiation and keep everyone safe,” says co-author Forget, an MIT professor of nuclear engineering and head of the Department of Nuclear Science and Engineering.

Vavrek, another co-lead-author, says that while in their study they focused on gamma-ray sources, he believes the computational tools they developed to extract directional information from the limited number of pixels are “much, much more general.” It isn’t restricted to certain wavelengths, it can also be used for neutrons, or even other forms of light, ultraviolet light, adds Hu, a senior scientist at MIT Nuclear Reactor Lab. 

Additional research team members include Ryan Pavlovsky, Victor Negut, Brian Quiter, and Joshua Cates at Lawrence Berkely National Laboratory, and Jiankai Yu, Tongtong Liu, Stephanie Jegelka at MIT. The work was supported by the U.S. Department of Energy.

###

Written by David L. Chandler, MIT News

Paper: “Tetris-inspired detector with neural network for radiation mapping” 

https://www.nature.com/articles/s41467-024-47338-w

 

---

JOURNAL

Nature Communications

DOI

10.1038/s41467-024-47338-w 

ARTICLE TITLE

“Tetris-inspired detector with neural network for radiation mapping”

'Time for Justice in Alabama': Supermajority of Mercedes-Benz Workers File for UAW Vote

"We are standing up for every worker in Alabama," said one employee. "We're going to turn things around with this vote. We're going to end the Alabama discount."


United Auto Workers members are seen at a rally in 2023.
(Photo: Bill Pugliano/Getty Images)

JULIA CONLEY
Apr 05, 2024
COMMON DREAMS

The alleged illegal union-busting that Mercedes-Benz autoworkers in Vance, Alabama accused the car company of in a complaint to the National Labor Relations Board has not weakened the resolve of pro-union employees, a supermajority of whom now support a union election, according to the United Auto Workers.

The union announced Friday that more than 5,000 workers at the company's nonunion plant have filed a petition with the NLRB in favor of an election, with the workers aiming for a vote by early May.

"It's time for change at Mercedes," said the UAW. "It's time for justice in Alabama. It's time for Mercedes workers to stand up. That's why Mercedes workers have filed for their vote to join the UAW, and to win a better life."

The announcement comes weeks after Volkswagen employees in Chattanooga, Tennessee filed for a union election that's expected to be held April 17-19.

Both union votes are the result of aggressive campaigning by the UAW, including union president Shawn Fain, in the wake of a historic "stand-up strike" that pushed the Big Three automakers to agree to new contracts for about 150,000 workers late last year.

After the victory, Fain announced the launch of the largest union organizing drive in U.S. history, aiming to welcome 150,000 workers at nonunion auto plants into the UAW.

Over 10,000 autoworkers in recent months have signed union cards, and the UAW said Friday that employees at more than two dozen facilities are also organizing.

Mercedes' two U.S. plants in Alabama and South Carolina are its only facilities in the world where workers are not represented by a union. Workers in Vance say they want better healthcare, retirement security, safety protocols, and paid sick days.

Jeremy Kimbrell, a measurement machine operator at Mercedes, said the union vote is part of an effort to ensure carmakers no longer view Alabama as a state where workers can be compensated unfairly.

"We are standing up for every worker in Alabama," said Kimbrell. "At Mercedes, at Hyundai, and at hundreds of other companies, Alabama workers have made billions of dollars for executives and shareholders, but we haven't gotten our fair share. We're going to turn things around with this vote. We're going to end the Alabama discount."

Moesha Chandler, an assembly team member, said her job has given her "serious problems with my shoulders and hands."

"We are voting for safer jobs at Mercedes," said Chandler. "When you're still in your 20s and your body is breaking down, that's not right. By winning our union, we'll have the power to make the work safer and more sustainable.

The UAW celebrated the news out of Vance by releasing a video showing a recent rally where Fain encouraged workers to support the union effort.




"You gotta believe you can win, that this job can be better, that your life will be better, and that those things are worth fighting for," Fain told the Mercedes workers. "That's why we stand up."

The growing pro-union movement across the South represents "huge stakes," said Lauren Kaori Gurley, a labor reporter for The Washington Post. The UAW has faced resistance from right-wing politicians across the South for decades as it has attempted to unionize factories.

Alabama Gov. Kay Ivey, a Republican, said Thursday that the UAW's efforts are a "threat from Detroit" that "has no interest in seeing the people of Alabama succeed."

Ivey's comments indicated that the governor "thinks so little of Alabama workers, that we're only good for cheap labor," Kimbrell told AL.com.

SURPRIZE

Biden, Promising Corporate Tax Increases, Has Cut Taxes Overall

Jim Tankersley
Mon, March 25, 2024 

President Joe Biden walks on stage during a visit to the Intel campus in Chandler, Ariz., March 20, 2024. (Tom Brenner/The New York Times)


WASHINGTON — President Joe Biden, amping up a populist pitch in his reelection campaign, has repeatedly said he would raise taxes on the wealthy and corporations to make them pay their “fair share.”

Republicans say Biden has “an unquenchable thirst for taxing the American people.” His Republican opponent in the election, former President Donald Trump, said recently that Biden was “going to give you the greatest, biggest, ugliest tax hike in the history of our country.”

So it might come as a surprise that, in just over three years in office, Biden has cut taxes overall.


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The math is straightforward. An analysis prepared for The New York Times by the Urban-Brookings Tax Policy Center, a Washington think tank that studies fiscal issues, shows that the tax cuts Biden has signed for individuals and corporations are larger than the tax increases he has imposed on big corporations and their shareholders.

The analysis estimates that the tax changes Biden has ushered into law will amount to a net cut of about $600 billion over four years and slightly more than that over a full decade.

“It’s reasonable to conclude from those numbers that the Biden tax policy hasn’t been some kind of radical tax-raising program,” said Benjamin R. Page, a senior fellow at the center and author of the analysis.

The analysis strictly looks at changes to taxes over the course of Biden’s presidency, including some direct benefits to people and businesses that flow through the tax code. It does not measure the effects of inflation or certain regulations, which Republicans sometimes label “tax hikes” since they can raise costs for companies and individuals.

It also does not measure the social or economic benefits of Biden’s spending policies, or of his regulatory efforts meant to help consumers, like cracking down on so-called junk fees and limiting the cost of insulin and other medication.

Instead, the analysis provides a comprehensive look at what Biden has done to the tax code, and how those policies add up.

It is clear by that measure that his record has not matched his own ambitions for taxing the rich and big companies — or Republicans’ attempts to caricature him as a tax-and-spend liberal.

That’s largely because Biden has struggled to pass his most ambitious tax-raising plans. “It’s what can be got through Congress and signed,” Page said. “They were subject to compromise.”

A White House spokesperson, Michael Kikukawa, said in an email that Biden was “proud to have cut taxes for the middle class and working families while cracking down on wealthy tax cheats and making big corporations pay more of their fair share.”

The president’s enacted tax cuts include incentives for companies to manufacture and install solar panels, wind turbines and other technologies meant to reduce fossil fuel emissions, which are a centerpiece of the climate law he signed in 2022. That law also contained tax cuts for people who buy certain low-emission technologies, such as electric vehicles and heat pumps.

Biden gave tax breaks to semiconductor factories as well, as part of a bipartisan advanced manufacturing bill he signed earlier that year.

The president also included temporary tax breaks for individuals and certain businesses in his 2021 economic stimulus bill, the American Rescue Plan. The legislation expanded a tax credit for parents. It provided $1,400 direct checks for low- and middle-income Americans, which were technically advance payments on tax credits.

Biden has partly offset all of his tax cuts with a pair of major new levies. Corporations are now required to pay a tax when they buy back their own stock. Another tax requires large corporations to pay a minimum 15% federal income tax, even if they qualify for deductions that would have made them owe less.

The president has also directed tens of billions of dollars to the IRS to help crack down on high earners and corporations that evade paying the taxes they owe — an effort that will increase federal tax revenues but does not increase tax rates.

But the president has struggled to persuade Congress — including a sufficient number of Democrats, in the two years his party controlled the House and the Senate on his watch — to sign on to a fleet of other proposed tax increases.

Biden’s budget requests have been filled with ideas for taxing high earners and corporations. Those have failed to gain traction on Capitol Hill. His most recent budget includes about $5 trillion of tax increases spread over a decade, including long-standing Democratic plans like raising the corporate income tax rate to 28% from 21%.

Republicans assailed Biden for tax plans they say will cripple the economy. Rep. Jodey Arrington, R-Texas, chair of the Budget Committee, said in a hearing Thursday that Biden believed “in more government and more spending and more taxing as the answers to the problems that our country faces.”

Biden has emphasized his tax proposals in recent weeks, including during his State of the Union address. The president has repeatedly said he would not raise taxes on people earning less than $400,000 a year, while calling on millionaires and billionaires to pay more.

He has also vaunted his tax record, as he did last week in Las Vegas. “In 2020, 55 of the largest Fortune 500 companies made $40 billion in profits,” Biden said. “They paid zero in federal taxes. Not anymore.”

Biden was referring to the corporate minimum tax created by the Inflation Reduction Act, the 2022 law that also included the climate-related tax incentives. The Treasury Department has struggled to implement that tax, which companies faced for the first time last year.

The department does not yet have data on how many corporations will pay the tax for 2023, officials said this week.

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