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    Versatile ‘nanocrystal gel’ could enable advances in energy, defense and telecommunications

    New applications in energy, defense and telecommunications could receive a boost after a team from The University of Texas at Austin created a new type of “nanocrystal gel” — a gel composed of tiny nanocrystals each 10,000 times smaller than the width of a human hair that are linked together into an organized network.
    The crux of the team’s discovery is that this new material is easily tunable. That is, it can be switched between two different states by changing the temperature. This means the material can work as an optical filter, absorbing different frequencies of light depending on whether it’s in a gelled state or not. So, it could be used, for example, on the outside of buildings to control heating or cooling dynamically. This type of optical filter also has applications for defense, particularly for thermal camouflage.
    The gels can be customized for these wide-ranging applications because both the nanocrystals and the molecular linkers that connect them into networks are designer components. Nanocrystals can be chemically tuned to be useful for routing communications through fiber optic networks or keep the temperature of space craft steady on remote planetary bodies. Linkers can be designed to cause gels to switch based on ambient temperature or detection of environmental toxins.
    “You could shift the apparent heat signature of an object by changing the infrared properties of its skin,” said Delia Milliron, professor and chair of the McKetta Department of Chemical Engineering in the Cockrell School of Engineering. “It could also be useful for telecommunications which all use infrared wavelengths.”
    The new research is published in the recent issue of the journal Science Advances.
    The team, led by graduate students Jiho Kang and Stephanie Valenzuela, did this work through the university’s Center for Dynamics and Control of Materials, a National Science Foundation Materials Research Science and Engineering Center that brings together engineers and scientists from across campus to collaborate on materials science research.
    The lab experiments allowed the team to see the material change back and forth between its two states of gel and not-gel (that is, free-floating nanocrystals suspended in liquid) that they triggered by specific temperature changes.
    Supercomputer simulations done at UT’s Texas Advanced Computing Center helped them to understand what was happening in the gel at the microscopic level when heat was applied. Based on theories of chemistry and physics, the simulations revealed the types of chemical bonds that hold the nanocrystals together in a network, and how those bonds break when hit with heat, causing the gel to break down.
    This is the second unique nanocrystal gel created by this team, and they continue to pursue advances in this arena. Kang is currently working to create a nanocrystal gel that can change between four states, making it even more versatile and useful. That gel would be a blend of two different types of nanocrystals, each able to switch between states in response to chemical signals or temperature changes. Such tunable nanocrystal gels are called “programmable” materials.
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    Materials provided by University of Texas at Austin. Note: Content may be edited for style and length. More

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    Core memory weavers and Navajo women made the Apollo missions possible

    The historic Apollo moon missions are often associated with high-visibility test flights, dazzling launches and spectacular feats of engineering. But intricate, challenging handiwork — comparable to weaving — was just as essential to putting men on the moon. Beyond Neil Armstrong, Buzz Aldrin and a handful of other names that we remember were hundreds of thousands of men and women who contributed to Apollo over a decade. Among them: the Navajo women who assembled state-of-the-art integrated circuits for the Apollo Guidance Computer and the women employees of Raytheon who wove the computer’s core memory.

    In 1962, when President John F. Kennedy declared that putting Americans on the moon should be the top priority for NASA, computers were large mainframes; they occupied entire rooms. And so one of the most daunting yet crucial challenges was developing a highly stable, reliable and portable computer to control and navigate the spacecraft.

    NASA chose to use cutting-edge integrated circuits in the Apollo Guidance Computer. These commercial circuits had been introduced only recently. Also known as microchips, they were revolutionizing electronics and computing, contributing to the gradual miniaturization of computers from mainframes to today’s smartphones. NASA sourced the circuits from the original Silicon Valley start-up, Fairchild Semiconductor. Fairchild was also leading the way in the practice known as outsourcing; the company opened a factory in Hong Kong in the early 1960s, which by 1966 employed 5,000 people, compared with Fairchild’s 3,000 California employees.

    At the same time, Fairchild sought low-cost labor within the United States. Lured by tax incentives and the promise of a labor force with almost no other employment options, Fairchild opened a plant in Shiprock, N.M., within the Navajo reservation, in 1965. The Fairchild factory operated until 1975 and employed more than 1,000 individuals at its peak, most of them Navajo women manufacturing integrated circuits.

    It was challenging work. Electrical components had to be placed on tiny chips made of a semiconductor such as silicon and connected by wires in precise locations, creating complex and varying patterns of lines and geometric shapes. The Navajo women’s work “was performed using a microscope and required painstaking attention to detail, excellent eyesight, high standards of quality and intense focus,” writes digital media scholar Lisa Nakamura.

    A brochure commemorating the dedication of Fairchild Semiconductor’s plant in Shiprock, N.M., included this Fairchild 9040 integrated circuit.Courtesy of the Computer History Museum

    In a brochure commemorating the dedication of the Shiprock plant, Fairchild directly compared the assembly of integrated circuits with what the company portrayed as the traditional, feminine, Indigenous craft of rug-weaving. The Shiprock brochure juxtaposed a photo of a microchip with one of a geometric-patterned rug, and another of a woman weaving such a rug. That portrayal, Nakamura argues, reinforced racial and gender stereotypes. The work was dismissed as “women’s work,” depriving the Navajo women of appropriate recognition and commensurate compensation.  Journalists and Fairchild employees also “depict[ed] electronics manufacture as a high-tech version of blanket weaving performed by willing and skillful Indigenous women,” Nakamura notes, yet “the women who performed this labor did so for the same reason that women have performed factory labor for centuries — to survive.”

    Far from the Shiprock desert, outside of Boston, women employees at Raytheon assembled the Apollo Guidance Computer’s core memory with a process that in this case directly mimicked weaving. Again, the moon missions demanded a stable and compact way of storing Apollo’s computing instructions. Core memory used metal wires threaded through tiny doughnut-shaped ferrite rings, or “cores,” to represent 1s and 0s. All of this core memory was woven by hand, with women sitting on opposite sides of a panel passing a wire-threaded needle back and forth to create a particular pattern. (In some cases, a woman worked alone, passing the needle through the panel to herself.)

    Women employees of Raytheon assembled core memory for the Apollo Guidance Computer by threading metal wires through rings. (This unnamed woman was described as a “space age needleworker” in a Raytheon press kit.)Courtesy of the collection of David Meerman Scott, Raytheon public relations

    Apollo engineers referred to this process of building memory as the “LOL,” or “Little Old Ladies,” method. Yet this work was so mission critical that it was tested and inspected multiple times. Mary Lou Rogers, who worked on Apollo, recalled, “[Each component] had to be looked at by three of four people before it was stamped off. We had a group of inspectors come in for the federal government to check our work all the time.”

    The core memory was also known as rope memory, and those who supervised its development were “rope mothers.” We know a great deal about one rope mother — Margaret Hamilton. She has been recognized with the Presidential Medal of Freedom, among other awards, and is now remembered as the woman who oversaw most of the Apollo software. But her efforts were unrecognized by many at the time. Hamilton recalled, “At the beginning, nobody thought software was that big a deal. But then they began to realize how much they were relying on it…. Astronauts‘ lives were at stake. Our software needed to be ultrareliable and it needed to be able to detect an error and recover from it at any time during the mission. And it all had to fit on the hardware.” Yet, little is known about the thousands of others who performed this mission-critical work of weaving integrated circuits and core memory.

    Margaret Hamilton is known for overseeing the development of the Apollo software. Draper Laboratory, restored by Adam Cuerden/Wikimedia Commons

    At the time, Fairchild’s representation of the Navajo women’s work as a feminine craft differentiated it from the high-status and masculine work of engineering. As Nakamura has written, the work “came to be understood as affective labor, or a ‘labor of love.’” Similarly, the work performed at Raytheon was described by Eldon Hall, who led the Apollo Guidance Computer’s hardware design, as “tender loving care.” Journalists and even a Raytheon manager presented this work as requiring no thinking and no skill.

    Recently, the communications scholar Samantha Shorey, engineer Daniela Rosner, technologist Brock Craft and quilt artist Helen Remick firmly overturned the notion that weaving core memory was a “no-brainer” with their Making Core Memory project. In nine workshops, they invited participants to weave core memory “patches” using metal matrices, beads and conductive threads, showcasing the deep focus and meticulous attention to detail required. The patches were then assembled in an electronic quilt that played aloud accounts from 1960s Apollo engineers and Raytheon managers. The Making Core Memory collaboration challenged the dichotomy of masculine, high-status, well-paid science and engineering cognitive labor versus feminine, low-status, low-paid, manual labor.

    A 1975 NASA report that summarized the Apollo missions spoke glowingly of the Apollo computing systems — but mentioned none of the Navajo or Raytheon women. “The performance of the computer was flawless,” the report declared. “Perhaps the most significant accomplishment during Apollo pertaining to guidance, navigation, and control was the demonstration of the versatility and adaptability of the computer software.”

    That computer, and that software, relied on the skilled, technical, embodied expertise and labor of thousands of women, including women of color. They were indubitably women of science, and their untold stories call us to reconsider who does science, and what counts as scientific expertise.  More

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    Forget handheld virtual reality controllers: a smile, frown or clench will suffice

    Our face can unlock a smartphone, provide access to a secure building and speed up passport control at airports, verifying our identity for numerous purposes.
    An international team of researchers from Australia, New Zealand and India has taken facial recognition technology to the next level, using a person’s expression to manipulate objects in a virtual reality setting without the use of a handheld controller or touchpad.
    In a world first study led by the University of Queensland, human computer interaction experts used neural processing techniques to capture a person’s smile, frown and clenched jaw and used each expression to trigger specific actions in virtual reality environments.
    One of the researchers involved in the experiment, University of South Australia’s Professor Mark Billinghurst, says the system has been designed to recognise different facial expressions via an EEG headset.
    “A smile was used to trigger the ‘move’ command; a frown for the ‘stop’ command and a clench for the ‘action’ command, in place of a handheld controller performing these actions,” says Prof Billinghurst.
    “Essentially we are capturing common facial expressions such as anger, happiness and surprise and implementing them in a virtual reality environment.”
    The researchers designed three virtual environments — happy, neutral and scary — and measured each person’s cognitive and physiological state while they were immersed in each scenario. More

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    CROPSR: A new tool to accelerate genetic discoveries

    Commercially viable biofuel crops are vital to reducing greenhouse gas emissions, and a new tool developed by the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI) should accelerate their development — as well as genetic editing advances overall.
    The genomes of crops are tailored by generations of breeding to optimize specific traits, and until recently breeders were limited to selection on naturally occurring diversity. CRISPR/Cas9 gene-editing technology can change this, but the software tools necessary for designing and evaluating CRISPR experiments have so far been based on the needs of editing in mammalian genomes, which don’t share the same characteristics as complex crop genomes.
    Enter CROPSR, the first open-source software tool for genome-wide design and evaluation of guide RNA (gRNA) sequences for CRISPR experiments, created by scientists at CABBI, a Department of Energy-funded Bioenergy Research Center (BRC). The genome-wide approach significantly shortens the time required to design a CRISPR experiment, reducing the challenge of working with crops and accelerating gRNA sequence design, evaluation, and validation, according to the study published in BMC Bioinformatics.
    “CROPSR provides the scientific community with new methods and a new workflow for performing CRISPR/Cas9 knockout experiments,” said CROPSR developer Hans Müller Paul, a molecular biologist and Ph.D. student with co-author Matthew Hudson, Professor of Crop Sciences at the University of Illinois Urbana-Champaign. “We hope that the new software will accelerate discovery and reduce the number of failed experiments.”
    To better meet the needs of crop geneticists, the team built software that lifts restrictions imposed by other packages on design and evaluation of gRNA sequences, the guides used to locate targeted genetic material. Team members also developed a new machine learning model that would not avoid guides for repetitive genomic regions often found in plants, a problem with existing tools. The CROPSR scoring model provided much more accurate predictions, even in non-crop genomes, the authors said.
    “The goal was to incorporate features to make life easier for the scientist,” Müller Paul said. More

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    Vortex microscope sees more than ever before

    Understanding the nitty gritty of how molecules interact with each other in the real, messy, dynamic environment of a living body is a challenge that must be overcome in order to understand a host of diseases, such as Alzheimer’s.
    Until now, researchers could capture the motion of a single molecule, and they could capture its rotation — how it tumbles as it bumps into surrounding molecules — but only by compromising 3D resolution.
    Now, the lab of Matthew Lew, assistant professor of electrical and systems engineering at the McKelvey School of Engineering at Washington University in St. Louis, has developed an imaging method that provides an unprecedented look at a molecule as it spins and rolls through liquid, providing the most comprehensive picture yet of molecular dynamics collected using optical microscopes.
    The research was published in a special issue of the Journal of Physical Chemistry B. The Feb. 17, 2022, Festschrift is dedicated to Nobel laureate William E. (W.E.) Moerner, an imaging pioneer, Washington University alumnus and mentor to more than 100 students over the years, including Lew.
    Moerner was the first person to observe optical signatures of a single molecule; previously, researchers weren’t sure it was even possible to measure such signals.
    Now Lew’s lab is the first to be able to visualize the orientation and direction of a molecule’s rotational movement — how it spins and wobbles — while it’s in a liquid system. More

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    Measuring the tempo of Utah's red rock towers

    You won’t see them move no matter how closely you watch.
    You won’t hear their vibrations, even with your ear pressed to the cool sandstone.
    But new research shows that the red rock towers found in Southern Utah and throughout the Colorado Plateau are in constant motion, vibrating with their own signature rhythms as unique as their dramatic profiles against the depth of the blue desert sky.
    University of Utah researchers know well how rock towers and arches shimmy, twist and sway in response to far-off earthquakes, wind and even ocean waves. Their latest research compiles a first-of-its-kind dataset to show that the dynamic properties, i.e. the frequencies at which the rocks vibrate and the ways they deform during that vibration, can be largely predicted using the same mathematics that describe how beams in built structures resonate.
    Knowing these properties is crucial to understanding the seismic stability of a rock tower and its susceptibility to hazardous vibrations. But it’s tough to get the needed data, partly because getting to the base of the towers often requires traveling through treacherous terrain — and then someone has to climb them to place a seismometer at the top.
    With the help of experienced climbers, though, University of Utah researchers have now measured the dynamic properties of 14 rock towers and fins in Utah, creating a unique dataset with a variety of heights and tower shapes. More

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    Chaining atoms together yields quantum storage

    Engineers at Caltech have developed an approach for quantum storage could help pave the way for the development of large-scale optical quantum networks.
    The new system relies on nuclear spins — the angular momentum of an atom’s nucleus — oscillating collectively as a spin wave. This collective oscillation effectively chains up several atoms to store information.
    The work, which is described in a paper published on February 16 in the journal Nature, utilizes a quantum bit (or qubit) made from an ion of ytterbium (Yb), a rare earth element also used in lasers. The team, led by Andrei Faraon (BS ’04), professor of applied physics and electrical engineering, embedded the ion in a transparent crystal of yttrium orthovanadate (YVO4) and manipulated its quantum states via a combination of optical and microwave fields. The team then used the Yb qubit to control the nuclear spin states of multiple surrounding vanadium atoms in the crystal.
    “Based on our previous work, single ytterbium ions were known to be excellent candidates for optical quantum networks, but we needed to link them with additional atoms. We demonstrate that in this work,” says Faraon, the co-corresponding author of the Nature paper.
    The device was fabricated at the Kavli Nanoscience Institute at Caltech, and then tested at very low temperatures in Faraon’s lab.
    A new technique to utilize entangled nuclear spins as a quantum memory was inspired by methods used in nuclear magnetic resonance (NMR). More