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  • richardmitnick 2:24 pm on February 18, 2019 Permalink | Reply
    Tags: , Applied Research & Technology, , , Rising Temperatures Reduce Colorado River Flow   

    From Eos: “Rising Temperatures Reduce Colorado River Flow” 

    From AGU
    Eos news bloc

    From Eos

    2.18.19
    Sarah Stanley

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    New research teases out the relative roles of hotter temperatures and declining precipitation in reducing the flow volume of the Colorado River, which feeds Lake Mead, pictured here [and much more]. Credit: John Fleck

    The Colorado River flows through seven U.S. states and northern Mexico, before discharging into the Gulf of California. Along the way, it provides drinking water to millions of people and irrigates thousands of square kilometers of cropland. However, although annual precipitation in the region increased by about 1% in the past century, the volume of water flowing down the river has dropped by over 15%.

    New research by Xiao et al. [Water Resources Research]. examines the causes behind this 100-year decline in natural flow, teasing out the relative contributions of rising temperatures and changes in precipitation. This work builds on a 2017 paper [Water Resources Research] showing that rising temperatures played a significant role in reduced flows during the Millennium Drought between 2000 and 2014.

    Rising temperatures can lower flow by increasing the amount of water lost to evaporation from soil and surface water, boosting the amount of water used by plants, lengthening the growing season, and shrinking snowpacks that contribute to flow via meltwater.

    To investigate the impact of rising temperatures on Colorado River flow over the past century, the authors of the new paper employed the Variable Infiltration Capacity (VIC) hydrologic model. The VIC model enabled them to simulate 100 years of flow at different locations throughout the vast network of tributaries and subbasins that make up the Colorado River system and to tease out the effects of long-term changes in precipitation and temperature throughout the entire Colorado River.

    The researchers found that rising temperatures are responsible for 53% of the long-term decline in the river’s flow, with changing precipitation patterns and other factors accounting for the rest. The sizable effects of rising temperatures are largely due to increased evaporation and water uptake by plants, as well as by sublimation of snowpacks.

    Additional simulations with the VIC model showed that warming drove 54% of the decline in flow seen during the Millennium Drought, which began in 2000 (and is ongoing). Flows also declined because precipitation fell on less productive (i.e., more arid) subbasins rather than on highly productive subbasins near the Continental Divide. This contrasts strongly with an earlier (1950s–1960s) drought of similar severity, which was caused almost entirely by below-normal precipitation over most of the basin.

    The authors note that the situation is complex, given different long-term trends and drought response across the basin, as well as seasonal differences in temperature and precipitation. Still, the new findings support an argument from the 2017 research that as global warming progresses, the relative contribution of rising temperatures to decreased Colorado River flow will increase.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

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  • richardmitnick 2:05 pm on February 18, 2019 Permalink | Reply
    Tags: "Can we trust scientific discoveries made using machine learning?", Applied Research & Technology, , Machine learning (ML) is a branch of statistics and computer science concerned with building computational systems that learn from data rather than following explicit instructions,   

    From Rice University: “Can we trust scientific discoveries made using machine learning?” 

    Rice U bloc

    From Rice University

    February 18, 2019

    Jeff Falk
    713-348-6775
    jfalk@rice.edu

    Jade Boyd
    713-348-6778
    jadeboyd@rice.edu

    Rice U. expert: Key is creating ML systems that question their own predictions.

    Rice University statistician Genevera Allen says scientists must keep questioning the accuracy and reproducibility of scientific discoveries made by machine-learning techniques until researchers develop new computational systems that can critique themselves.

    1
    Genevera Allen (Photo by Tommy LaVergne/Rice University)

    Allen, associate professor of statistics, computer science and electrical and computer engineering at Rice and of pediatrics-neurology at Baylor College of Medicine, will address the topic in both a press briefing and a general session today at the 2019 Annual Meeting of the American Association for the Advancement of Science (AAAS).

    “The question is, ‘Can we really trust the discoveries that are currently being made using machine-learning techniques applied to large data sets?’” Allen said. “The answer in many situations is probably, ‘Not without checking,’ but work is underway on next-generation machine-learning systems that will assess the uncertainty and reproducibility of their predictions.”

    Machine learning (ML) is a branch of statistics and computer science concerned with building computational systems that learn from data rather than following explicit instructions. Allen said much attention in the ML field has focused on developing predictive models that allow ML to make predictions about future data based on its understanding of data it has studied.

    “A lot of these techniques are designed to always make a prediction,” she said. “They never come back with ‘I don’t know,’ or ‘I didn’t discover anything,’ because they aren’t made to.”

    She said uncorroborated data-driven discoveries from recently published ML studies of cancer data are a good example.

    “In precision medicine, it’s important to find groups of patients that have genomically similar profiles so you can develop drug therapies that are targeted to the specific genome for their disease,” Allen said. “People have applied machine learning to genomic data from clinical cohorts to find groups, or clusters, of patients with similar genomic profiles.

    “But there are cases where discoveries aren’t reproducible; the clusters discovered in one study are completely different than the clusters found in another,” she said. “Why? Because most machine-learning techniques today always say, ‘I found a group.’ Sometimes, it would be far more useful if they said, ‘I think some of these are really grouped together, but I’m uncertain about these others.’”

    Allen will discuss uncertainty and reproducibility of ML techniques for data-driven discoveries at a 10 a.m. press briefing today, and she will discuss case studies and research aimed at addressing uncertainty and reproducibility in the 3:30 p.m. general session, “Machine Learning and Statistics: Applications in Genomics and Computer Vision.” Both sessions are at the Marriott Wardman Park Hotel.

    Allen is the founding director of Rice’s Center for Transforming Data to Knowledge (D2K Lab) and a member of the Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital. Her research lies in the areas of modern multivariate analysis, graphical models, statistical machine learning and data integration, with a particular focus on statistical methods that help scientists make sense of “big data” from high-throughput genomics, neuroimaging and other applications. Her previous honors include a National Science Foundation CAREER award, the International Biometric Society’s Young Statistician Showcase award and Forbes ’30 under 30′ in science and health care.

    AAAS is the world’s largest multi-disciplinary science society, and the AAAS Annual Meeting, Feb. 14-17, is the world’s largest general scientific gathering. For more information, visit: https://aaas.org.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    stem

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 9:05 pm on February 17, 2019 Permalink | Reply
    Tags: "The Secret History of Women in Coding", Applied Research & Technology, ,   

    From The New York Times: Women In STEM-“The Secret History of Women in Coding” 

    New York Times

    From The New York Times

    Feb. 13, 2019
    Clive Thompson

    Computer programming once had much better gender balance than it does today. What went wrong?

    1
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    Mary Allen Wilkes with a LINC at M.I.T., where she was a programmer. Credit Joseph C. Towler, Jr.

    As a teenager in Maryland in the 1950s, Mary Allen Wilkes had no plans to become a software pioneer — she dreamed of being a litigator. One day in junior high in 1950, though, her geography teacher surprised her with a comment: “Mary Allen, when you grow up, you should be a computer programmer!” Wilkes had no idea what a programmer was; she wasn’t even sure what a computer was. Relatively few Americans were. The first digital computers had been built barely a decade earlier at universities and in government labs.

    By the time she was graduating from Wellesley College in 1959, she knew her legal ambitions were out of reach. Her mentors all told her the same thing: Don’t even bother applying to law school. “They said: ‘Don’t do it. You may not get in. Or if you get in, you may not get out. And if you get out, you won’t get a job,’ ” she recalls. If she lucked out and got hired, it wouldn’t be to argue cases in front of a judge. More likely, she would be a law librarian, a legal secretary, someone processing trusts and estates.

    But Wilkes remembered her junior high school teacher’s suggestion. In college, she heard that computers were supposed to be the key to the future. She knew that the Massachusetts Institute of Technology had a few of them.


    So on the day of her graduation, she had her parents drive her over to M.I.T. and marched into the school’s employment office. “Do you have any jobs for computer programmers?” she asked. They did, and they hired her.

    It might seem strange now that they were happy to take on a random applicant with absolutely no experience in computer programming. But in those days, almost nobody had any experience writing code. The discipline did not yet really exist; there were vanishingly few college courses in it, and no majors. (Stanford, for example, didn’t create a computer-science department until 1965.) So instead, institutions that needed programmers just used aptitude tests to evaluate applicants’ ability to think logically. Wilkes happened to have some intellectual preparation: As a philosophy major, she had studied symbolic logic, which can involve creating arguments and inferences by stringing together and/or statements in a way that resembles coding.

    Wilkes quickly became a programming whiz. She first worked on the IBM 704, which required her to write in an abstruse “assembly language.”

    7
    An IBM 704 computer, with IBM 727 tape drives and IBM 780 CRT display. (Image courtesy of LLNL.)

    (A typical command might be something like “LXA A, K,” telling the computer to take the number in Location A of its memory and load it into to the “Index Register” K.) Even getting the program into the IBM 704 was a laborious affair. There were no keyboards or screens; Wilkes had to write a program on paper and give it to a typist, who translated each command into holes on a punch card. She would carry boxes of commands to an “operator,” who then fed a stack of such cards into a reader. The computer executed the program and produced results, typed out on a printer.

    Often enough, Wilkes’s code didn’t produce the result she wanted. So she had to pore over her lines of code, trying to deduce her mistake, stepping through each line in her head and envisioning how the machine would execute it — turning her mind, as it were, into the computer. Then she would rewrite the program. The capacity of most computers at the time was quite limited; the IBM 704 could handle only about 4,000 “words” of code in its memory. A good programmer was concise and elegant and never wasted a word. They were poets of bits. “It was like working logic puzzles — big, complicated logic puzzles,” Wilkes says. “I still have a very picky, precise mind, to a fault. I notice pictures that are crooked on the wall.”

    What sort of person possesses that kind of mentality? Back then, it was assumed to be women. They had already played a foundational role in the prehistory of computing: During World War II, women operated some of the first computational machines used for code-breaking at Bletchley Park in Britain.

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    A Colossus Mark 2 computer being operated by Wrens. The slanted control panel on the left was used to set the “pin” (or “cam”) patterns of the Lorenz. The “bedstead” paper tape transport is on the right.

    Develope-Tommy Flowers, assisted by Sidney Broadhurst, William Chandler and for the Mark 2 machines, Allen Coombs
    Manufacturer-Post Office Research Station
    Type-Special-purpose electronic digital programmable computer
    Generation-First-generation computer
    Release date Mk 1: December 1943 Mk 2: 1 June 1944
    Discontinued 1960

    8
    The Lorenz SZ machines had 12 wheels, each with a different number of cams (or “pins”).
    Wheel number 1 2 3 4 5 6 7 8 9 10 11 12
    BP wheel name[13] ψ1 ψ2 ψ3 ψ4 ψ5 μ37 μ61 χ1 χ2 χ3 χ4 χ5
    Number of cams (pins) 43 47 51 53 59 37 61 41 31 29 26 23

    Colossus was a set of computers developed by British codebreakers in the years 1943–1945 to help in the cryptanalysis of the Lorenz cipher. Colossus used thermionic valves (vacuum tubes) to perform Boolean and counting operations. Colossus is thus regarded as the world’s first programmable, electronic, digital computer, although it was programmed by switches and plugs and not by a stored program.

    Colossus was designed by research telephone engineer Tommy Flowers to solve a problem posed by mathematician Max Newman at the Government Code and Cypher School (GC&CS) at Bletchley Park. Alan Turing’s use of probability in cryptanalysis (see Banburismus) contributed to its design. It has sometimes been erroneously stated that Turing designed Colossus to aid the cryptanalysis of the Enigma.Turing’s machine that helped decode Enigma was the electromechanical Bombe, not Colossus.

    In the United States, by 1960, according to government statistics, more than one in four programmers were women. At M.I.T.’s Lincoln Labs in the 1960s, where Wilkes worked, she recalls that most of those the government categorized as “career programmers” were female. It wasn’t high-status work — yet.

    In 1961, Wilkes was assigned to a prominent new project, the creation of the LINC.

    LINC from MIT Lincoln Lab


    Wesley Clark in 1962 at a demonstration of the first Laboratory Instrument Computer, or LINC. Credit MIT Lincoln Laboratory

    As one of the world’s first interactive personal computers, it would be a breakthrough device that could fit in a single office or lab. It would even have its own keyboard and screen, so it could be programmed more quickly, without awkward punch cards or printouts. The designers, who knew they could make the hardware, needed Wilkes to help write the software that would let a user control the computer in real time.

    For two and a half years, she and a team toiled away at flow charts, pondering how the circuitry functioned, how to let people communicate with it. “We worked all these crazy hours; we ate all kinds of terrible food,” she says. There was sexism, yes, especially in the disparity between how men and women were paid and promoted, but Wilkes enjoyed the relative comity that existed among the men and women at Lincoln Labs, the sense of being among intellectual peers. “We were a bunch of nerds,” Wilkes says dryly. “We were a bunch of geeks. We dressed like geeks. I was completely accepted by the men in my group.” When they got an early prototype of the LINC working, it solved a fiendish data-processing problem for a biologist, who was so excited that he danced a happy jig around the machine.

    In late 1964, after Wilkes returned from traveling around the world for a year, she was asked to finish writing the LINC’s operating system. But the lab had been relocated to St. Louis, and she had no desire to move there. Instead, a LINC was shipped to her parents’ house in Baltimore. Looming in the front hall near the foot of the stairs, a tall cabinet of whirring magnetic tapes across from a refrigerator-size box full of circuitry, it was an early glimpse of a sci-fi future: Wilkes was one of the first people on the planet to have a personal computer in her home. (Her father, an Episcopal clergyman, was thrilled. “He bragged about it,” she says. “He would tell anybody who would listen, ‘I bet you don’t have a computer in your living room.’ ”) Before long, LINC users around the world were using her code to program medical analyses and even create a chatbot that interviewed patients about their symptoms.

    But even as Wilkes established herself as a programmer, she still craved a life as a lawyer. “I also really finally got to the point where I said, ‘I don’t think I want to do this for the rest of my life,’ ” she says. Computers were intellectually stimulating but socially isolating. In 1972, she applied and got in to Harvard Law School, and after graduating, she spent the next four decades as a lawyer. “I absolutely loved it,” she says.

    Today Wilkes is retired and lives in Cambridge, Mass. White-haired at 81, she still has the precise mannerisms and the ready, beaming smile that can be seen in photos from the ’60s, when she posed, grinning, beside the LINC. She told me that she occasionally gives talks to young students studying computer science. But the industry they’re heading into is, astonishingly, less populated with women — and by many accounts less welcoming to them — than it was in Wilkes’s day. In 1960, when she started working at M.I.T., the proportion of women in computing and mathematical professions (which are grouped together in federal government data) was 27 percent. It reached 35 percent in 1990. But, in the government’s published figures, that was the peak. The numbers fell after that, and by 2013, women were down to 26 percent — below their share in 1960.

    When Wilkes talks to today’s young coders, they are often shocked to learn that women were among the field’s earliest, towering innovators and once a common sight in corporate America. “Their mouths are agape,” Wilkes says. “They have absolutely no idea.”

    Almost 200 years ago, the first person to be what we would now call a coder was, in fact, a woman: Lady Ada Lovelace.

    4
    Ada Lovelace aka Augusta Ada Byron-1843 or 1850 a rare daguerreotype by Antoine Claudet. Picture taken in his studio probably near Regents Park in London
    Date 2 January 1843
    Source https://blogs.bodleian.ox.ac.uk/adalovelace/2015/10/14/only-known-photographs-of-ada-lovelace-in-bodleian-display/ Reproduction courtesy of Geoffrey Bond.
    Augusta Ada King, Countess of Lovelace (née Byron; 10 December 1815 – 27 November 1852) was an English mathematician and writer, chiefly known for her work on Charles Babbage’s proposed mechanical general-purpose computer, the Analytical Engine [below]. She was the first to recognise that the machine had applications beyond pure calculation, and published the first algorithm intended to be carried out by such a machine. As a result, she is sometimes regarded as the first to recognise the full potential of a “computing machine” and the first computer programmer.

    Analytical Engine was a proposed mechanical general-purpose computer designed by English mathematician and computer pioneer Charles Babbage. It was first described in 1837 as the successor to Babbage’s difference engine

    As a young mathematician in England in 1833, she met Charles Babbage, an inventor who was struggling to design what he called the Analytical Engine, which would be made of metal gears and able to execute if/then commands and store information in memory. Enthralled, Lovelace grasped the enormous potential of a device like this. A computer that could modify its own instructions and memory could be far more than a rote calculator, she realized. To prove it, Lovelace wrote what is often regarded as the first computer program in history, an algorithm with which the Analytical Engine would calculate the Bernoulli sequence of numbers. (She wasn’t shy about her accomplishments: “That brain of mine is something more than merely mortal; as time will show,” she once wrote.) But Babbage never managed to build his computer, and Lovelace, who died of cancer at 36, never saw her code executed.

    Analytical Engine was a proposed mechanical general-purpose computer designed by English mathematician and computer pioneer Charles Babbage. It was first described in 1837 as the successor to Babbage’s difference engine

    When digital computers finally became a practical reality in the 1940s, women were again pioneers in writing software for the machines. At the time, men in the computing industry regarded writing code as a secondary, less interesting task. The real glory lay in making the hardware. Software? “That term hadn’t yet been invented,” says Jennifer S. Light, a professor at M.I.T. who studies the history of science and technology.

    This dynamic was at work in the development of the first programmable digital computer in the United States, the Electronic Numerical Integrator and Computer, or Eniac, during the 1940s.

    3
    Computer operators with an Eniac — the world’s first programmable general-purpose computer. Credit Corbis/Getty Images

    ENIAC progamming. Columbia University

    Funded by the military, the thing was a behemoth, weighing more than 30 tons and including 17,468 vacuum tubes. Merely getting it to work was seen as the heroic, manly engineering feat. In contrast, programming it seemed menial, even secretarial. Women had long been employed in the scut work of doing calculations. In the years leading up to the Eniac, many companies bought huge electronic tabulating machines — quite useful for tallying up payroll, say — from companies like IBM; women frequently worked as the punch-card operators for these overgrown calculators. When the time came to hire technicians to write instructions for the Eniac, it made sense, to the men in charge, to pick an all-female team: Kathleen McNulty, Jean Jennings, Betty Snyder, Marlyn Wescoff, Frances Bilas and Ruth Lichterman. The men would figure out what they wanted Eniac to do; the women “programmed” it to execute the instructions.

    “We could diagnose troubles almost down to the individual vacuum tube,” Jennings later told an interviewer for the IEEE Annals of the History of Computing. Jennings, who grew up as the tomboy daughter of low-income parents near a Missouri community of 104 people, studied math at college. “Since we knew both the application and the machine, we learned to diagnose troubles as well as, if not better than, the engineer.”

    The Eniac women were among the first coders to discover that software never works right the first time — and that a programmer’s main work, really, is to find and fix the bugs. Their innovations included some of software’s core concepts. Betty Snyder realized that if you wanted to debug a program that wasn’t running correctly, it would help to have a “break point,” a moment when you could stop a program midway through its run. To this day, break points are a key part of the debugging process.

    In 1946, Eniac’s creators wanted to show off the computer to a group of leaders in science, technology and the military. They asked Jennings and Snyder to write a program that calculated missile trajectories. After weeks of intense effort, they and their team had a working program, except for one glitch: It was supposed to stop when the missile landed, but for some reason it kept running. The night before the demo, Snyder suddenly intuited the problem. She went to work early the next day, flipped a single switch inside the Eniac and eliminated the bug. “Betty could do more logical reasoning while she was asleep than most people can do awake,” Jennings later said. Nonetheless, the women got little credit for their work. At that first official demonstration to show off Eniac, the male project managers didn’t mention, much less introduce, the women.

    After the war, as coding jobs spread from the military into the private sector, women remained in the coding vanguard, doing some of the highest-profile work.

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    Rear Admiral Grace M. Hopper, 1984

    Grace Brewster Murray Hopper (née Murray; December 9, 1906 – January 1, 1992) was an American computer scientist and United States Navy rear admiral. One of the first programmers of the Harvard Mark I computer, she was a pioneer of computer programming who invented one of the first compiler related tools. She popularized the idea of machine-independent programming languages, which led to the development of COBOL, an early high-level programming language still in use today.

    The pioneering programmer Grace Hopper is frequently credited with creating the first “compiler,” a program that lets users create programming languages that more closely resemble regular written words: A coder could thus write the English-like code, and the compiler would do the hard work of turning it into ones and zeros for the computer. Hopper also developed the “Flowmatic” language for nontechnical businesspeople. Later, she advised the team that created the Cobol language, which became widely used by corporations. Another programmer from the team, Jean E. Sammet, continued to be influential in the language’s development for decades. Fran Allen was so expert in optimizing Fortran, a popular language for performing scientific calculations, that she became the first female IBM fellow.

    NERSC Hopper Cray XE6 supercomputer

    When the number of coding jobs exploded in the ’50s and ’60s as companies began relying on software to process payrolls and crunch data, men had no special advantage in being hired. As Wilkes had discovered, employers simply looked for candidates who were logical, good at math and meticulous. And in this respect, gender stereotypes worked in women’s favor: Some executives argued that women’s traditional expertise at painstaking activities like knitting and weaving manifested precisely this mind-set. (The 1968 book Your Career in Computers stated that people who like “cooking from a cookbook” make good programmers.)

    The field rewarded aptitude: Applicants were often given a test (typically one involving pattern recognition), hired if they passed it and trained on the job, a process that made the field especially receptive to neophytes. “Know Nothing About Computers? Then We’ll Teach You (and Pay You While Doing So),” one British ad promised in 1965. In a 1957 recruiting pitch in the United States, IBM’s brochure titled My Fair Ladies specifically encouraged women to apply for coding jobs.

    Such was the hunger for programming talent that a young black woman named Arlene Gwendolyn Lee [no photo available] could become one of the early female programmers in Canada, despite the open discrimination of the time. Lee was half of a biracial couple to whom no one would rent, so she needed money to buy a house. According to her son, who has described his mother’s experience in a blog post, Lee showed up at a firm after seeing its ad for data processing and systems analytics jobs in a Toronto newspaper sometime in the early 1960s. Lee persuaded the employers, who were all white, to let her take the coding aptitude test. When she placed in the 99th percentile, the supervisors grilled her with questions before hiring her. “I had it easy,” she later told her son. “The computer didn’t care that I was a woman or that I was black. Most women had it much harder.”

    Elsie Shutt learned to code during her college summers while working for the military at the Aberdeen Proving Ground, an Army facility in Maryland.

    8
    Elsie Shutt founded one of the first software businesses in the U.S. in 1958

    In 1953, while taking time off from graduate school, she was hired to code for Raytheon, where the programmer work force “was about 50 percent men and 50 percent women,” she told Janet Abbate, a Virginia Tech historian and author of the 2012 book Recoding Gender. “And it really amazed me that these men were programmers, because I thought it was women’s work!”

    When Shutt had a child in 1957, state law required her to leave her job; the ’50s and ’60s may have been welcoming to full-time female coders, but firms were unwilling to offer part-time work, even to superb coders. So Shutt founded Computations Inc., a consultancy that produced code for corporations. She hired stay-at-home mothers as part-time employees; if they didn’t already know how to code, she trained them. They cared for their kids during the day, then coded at night, renting time on local computers. “What it turned into was a feeling of mission,” Shutt told Abbate, “in providing work for women who were talented and did good work and couldn’t get part-time jobs.” Business Week called the Computations work force the “pregnant programmers” in a 1963 article illustrated with a picture of a baby in a bassinet in a home hallway, with the mother in the background, hard at work writing software. (The article’s title: Mixing Math and Motherhood.)

    By 1967, there were so many female programmers that Cosmopolitan magazine published an article about The Computer Girls, accompanied by pictures of beehived women at work on computers that evoked the control deck of the U.S.S. Enterprise. The story noted that women could make $20,000 a year doing this work (or more than $150,000 in today’s money). It was the rare white-collar occupation in which women could thrive. Nearly every other highly trained professional field admitted few women; even women with math degrees had limited options: teaching high school math or doing rote calculations at insurance firms.

    “Women back then would basically go, ‘Well, if I don’t do programming, what else will I do?’ ” Janet Abbate says. “The situation was very grim for women’s opportunities.”

    If we want to pinpoint a moment when women began to be forced out of programming, we can look at one year: 1984. A decade earlier, a study revealed that the numbers of men and women who expressed an interest in coding as a career were equal. Men were more likely to enroll in computer-science programs, but women’s participation rose steadily and rapidly through the late ’70s until, by the 1983-84 academic year, 37.1 percent of all students graduating with degrees in computer and information sciences were women. In only one decade, their participation rate more than doubled.

    But then things went into reverse. From 1984 onward, the percentage dropped; by the time 2010 rolled around, it had been cut in half. Only 17.6 percent of the students graduating from computer-science and information-science programs were women.

    One reason for this vertiginous decline has to do with a change in how and when kids learned to program. The advent of personal computers in the late ’70s and early ’80s remade the pool of students who pursued computer-science degrees. Before then, pretty much every student who showed up at college had never touched a computer or even been in the room with one. Computers were rare and expensive devices, available for the most part only in research labs or corporate settings. Nearly all students were on equal footing, in other words, and new to programming.

    Once the first generation of personal computers, like the Commodore 64 or the TRS-80, found their way into homes, teenagers were able to play around with them, slowly learning the major concepts of programming in their spare time.

    9
    Commodore 64

    10
    Radio Shack Tandy TRS80

    By the mid-’80s, some college freshmen were showing up for their first class already proficient as programmers. They were remarkably well prepared for and perhaps even a little jaded about what Computer Science 101 might bring. As it turned out, these students were mostly men, as two academics discovered when they looked into the reasons women’s enrollment was so low.

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    Keypunch operators at IBM in Stockholm in the 1930s. Credit IBM

    One researcher was Allan Fisher, then the associate dean of the computer-science school at Carnegie Mellon University. The school established an undergraduate program in computer science in 1988, and after a few years of operation, Fisher noticed that the proportion of women in the major was consistently below 10 percent. In 1994, he hired Jane Margolis, a social scientist who is now a senior researcher in the U.C.L.A. School of Education and Information Studies, to figure out why. Over four years, from 1995 to 1999, she and her colleagues interviewed and tracked roughly 100 undergraduates, male and female, in Carnegie Mellon’s computer-science department; she and Fisher later published the findings in their 2002 book “Unlocking the Clubhouse: Women in Computing.”

    What Margolis discovered was that the first-year students arriving at Carnegie Mellon with substantial experience were almost all male. They had received much more exposure to computers than girls had; for example, boys were more than twice as likely to have been given one as a gift by their parents. And if parents bought a computer for the family, they most often put it in a son’s room, not a daughter’s. Sons also tended to have what amounted to an “internship” relationship with fathers, working through Basic-language manuals with them, receiving encouragement from them; the same wasn’t true for daughters. “That was a very important part of our findings,” Margolis says. Nearly every female student in computer science at Carnegie Mellon told Margolis that her father had worked with her brother — “and they had to fight their way through to get some attention.”

    Their mothers were typically less engaged with computers in the home, they told her. Girls, even the nerdy ones, picked up these cues and seemed to dial back their enthusiasm accordingly. These were pretty familiar roles for boys and girls, historically: Boys were cheered on for playing with construction sets and electronics kits, while girls were steered toward dolls and toy kitchens. It wasn’t terribly surprising to Margolis that a new technology would follow the same pattern as it became widely accepted.

    At school, girls got much the same message: Computers were for boys. Geeky boys who formed computer clubs, at least in part to escape the torments of jock culture, often wound up, whether intentionally or not, reproducing the same exclusionary behavior. (These groups snubbed not only girls but also black and Latino boys.) Such male cliques created “a kind of peer support network,” in Fisher’s words.

    This helped explain why Carnegie Mellon’s first-year classes were starkly divided between the sizable number of men who were already confident in basic programming concepts and the women who were frequently complete neophytes. A cultural schism had emerged. The women started doubting their ability. How would they ever catch up?

    What Margolis heard from students — and from faculty members, too — was that there was a sense in the classroom that if you hadn’t already been coding obsessively for years, you didn’t belong. The “real programmer” was the one who “had a computer-screen tan from being in front of the monitor all the time,” as Margolis puts it. “The idea was, you just have to love being with a computer all the time, and if you don’t do it 24/7, you’re not a ‘real’ programmer.” The truth is, many of the men themselves didn’t fit this monomaniacal stereotype. But there was a double standard: While it was O.K. for the men to want to engage in various other pursuits, women who expressed the same wish felt judged for not being “hard core” enough. By the second year, many of these women, besieged by doubts, began dropping out of the program. (The same was true for the few black and Latino students who also arrived on campus without teenage programming experience.)

    A similar pattern took hold at many other campuses. Patricia Ordóñez, a first-year student at Johns Hopkins University in 1985, enrolled in an Introduction to Minicomputers course. She had been a math whiz in high school but had little experience in coding; when she raised her hand in class at college to ask a question, many of the other students who had spent their teenage years programming — and the professor — made her feel singled out. “I remember one day he looked at me and said, ‘You should already know this by now,’ ” she told me. “I thought, I’m never going to succeed.” She switched majors as a result.

    Yet a student’s decision to stick with or quit the subject did not seem to be correlated with coding talent. Many of the women who dropped out were getting perfectly good grades, Margolis learned. Indeed, some who left had been top students. And the women who did persist and made it to the third year of their program had by then generally caught up to the teenage obsessives. The degree’s coursework was, in other words, a leveling force. Learning Basic as a teenage hobby might lead to lots of fun and useful skills, but the pace of learning at college was so much more intense that by the end of the degree, everyone eventually wound up graduating at roughly the same levels of programming mastery.

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    An E.R.A./Univac 1103 computer in the 1950s.Credit Hum Images/Alamy

    “It turned out that having prior experience is not a great predictor, even of academic success,” Fisher says. Ordóñez’s later experience illustrates exactly this: After changing majors at Johns Hopkins, she later took night classes in coding and eventually got a Ph.D. in computer science in her 30s; today, she’s a professor at the University of Puerto Rico Río Piedras, specializing in data science.

    By the ’80s, the early pioneering work done by female programmers had mostly been forgotten. In contrast, Hollywood was putting out precisely the opposite image: Computers were a male domain. In hit movies like Revenge of the Nerds, Weird Science, Tron, WarGames and others, the computer nerds were nearly always young white men. Video games, a significant gateway activity that led to an interest in computers, were pitched far more often at boys, as research in 1985 by Sara Kiesler [Psychology of Women Quartly], a professor at Carnegie Mellon, found. “In the culture, it became something that guys do and are good at,” says Kiesler, who is also a program manager at the National Science Foundation. “There were all kinds of things signaling that if you don’t have the right genes, you’re not welcome.”

    A 1983 study involving M.I.T. students produced equally bleak accounts. Women who raised their hands in class were often ignored by professors and talked over by other students. They would be told they weren’t aggressive enough; if they challenged other students or contradicted them, they heard comments like “You sure are bitchy today — must be your period.” Behavior in some research groups “sometimes approximates that of the locker room,” the report concluded, with men openly rating how “cute” their female students were. (“Gee, I don’t think it’s fair that the only two girls in the group are in the same office,” one said. “We should share.”) Male students mused about women’s mediocrity: “I really don’t think the woman students around here are as good as the men,” one said.

    By then, as programming enjoyed its first burst of cultural attention, so many students were racing to enroll in computer science that universities ran into a supply problem: They didn’t have enough professors to teach everyone. Some added hurdles, courses that students had to pass before they could be accepted into the computer-science major. Punishing workloads and classes that covered the material at a lightning pace weeded out those who didn’t get it immediately. All this fostered an environment in which the students mostly likely to get through were those who had already been exposed to coding — young men, mostly. “Every time the field has instituted these filters on the front end, that’s had the effect of reducing the participation of women in particular,” says Eric S. Roberts, a longtime professor of computer science, now at Reed College, who first studied this problem and called it the “capacity crisis.”

    When computer-science programs began to expand again in the mid-’90s, coding’s culture was set. Most of the incoming students were men. The interest among women never recovered to the levels reached in the late ’70s and early ’80s. And the women who did show up were often isolated. In a room of 20 students, perhaps five or even fewer might be women.

    In 1991, Ellen Spertus, now a computer scientist at Mills College, published a report on women’s experiences in programming classes. She cataloged a landscape populated by men who snickered about the presumed inferiority of women and by professors who told female students that they were “far too pretty” to be studying electrical engineering; when some men at Carnegie Mellon were asked to stop using pictures of naked women as desktop wallpaper on their computers, they angrily complained that it was censorship of the sort practiced by “the Nazis or the Ayatollah Khomeini.”

    As programming was shutting its doors to women in academia, a similar transformation was taking place in corporate America. The emergence of what would be called “culture fit” was changing the who, and the why, of the hiring process. Managers began picking coders less on the basis of aptitude and more on how well they fit a personality type: the acerbic, aloof male nerd.

    The shift actually began far earlier, back in the late ’60s, when managers recognized that male coders shared a growing tendency to be antisocial isolates, lording their arcane technical expertise over that of their bosses. Programmers were “often egocentric, slightly neurotic,” as Richard Brandon, a well-known computer-industry analyst, put it in an address at a 1968 conference, adding that “the incidence of beards, sandals and other symptoms of rugged individualism or nonconformity are notably greater among this demographic.”

    In addition to testing for logical thinking, as in Mary Allen Wilkes’s day, companies began using personality tests to select specifically for these sorts of caustic loner qualities. “These became very powerful narratives,” says Nathan Ensmenger, a professor of informatics at Indiana University, who has studied [Gender and Computing] this transition. The hunt for that personality type cut women out. Managers might shrug and accept a man who was unkempt, unshaven and surly, but they wouldn’t tolerate a women who behaved the same way. Coding increasingly required late nights, but managers claimed that it was too unsafe to have women working into the wee hours, so they forbid them to stay late with the men.

    At the same time, the old hierarchy of hardware and software became inverted. Software was becoming a critical, and lucrative, sector of corporate America. Employers increasingly hired programmers whom they could envision one day ascending to key managerial roles in programming. And few companies were willing to put a woman in charge of men. “They wanted people who were more aligned with management,” says Marie Hicks, a historian at the Illinois Institute of Technology. “One of the big takeaways is that technical skill does not equate to success.”

    By the 1990s and 2000s, the pursuit of “culture fit” was in full force, particularly at start-ups, which involve a relatively small number of people typically confined to tight quarters for long hours. Founders looked to hire people who were socially and culturally similar to them.

    “It’s all this loosey-goosey ‘culture’ thing,” says Sue Gardner, former head of the Wikimedia Foundation, the nonprofit that hosts Wikipedia and other sites. After her stint there, Gardner decided to study why so few women were employed as coders. In 2014, she surveyed more than 1,400 women in the field and conducted sit-down interviews with scores more. It became clear to her that the occupation’s takeover by men in the ’90s had turned into a self-perpetuating cycle. Because almost everyone in charge was a white or Asian man, that was the model for whom to hire; managers recognized talent only when it walked and talked as they did. For example, many companies have relied on whiteboard challenges when hiring a coder — a prospective employee is asked to write code, often a sorting algorithm, on a whiteboard while the employers watch. This sort of thing bears almost no resemblance to the work coders actually do in their jobs. But whiteboard questions resemble classroom work at Ivy League institutions. It feels familiar to the men doing the hiring, many of whom are only a few years out of college. “What I came to realize,” Gardner says, “is that it’s not that women are excluded. It’s that practically everyone is excluded if you’re not a young white or Asian man who’s single.”

    One coder, Stephanie Hurlburt, was a stereotypical math nerd who had deep experience working on graphics software. “I love C++, the low-level stuff,” she told me, referring to a complex language known for allowing programmers to write very fast-running code, useful in graphics. Hurlburt worked for a series of firms this decade, including Unity (which makes popular software for designing games), and then for Facebook on its Oculus Rift VR headset, grinding away for long hours in the run-up to the release of its first demo. Hurlburt became accustomed to shrugging off negative attention and crude sexism. She heard, including from many authority figures she admired, that women weren’t wired for math. While working as a coder, if she expressed ignorance of any concept, no matter how trivial, male colleagues would disparage her. “I thought you were at a higher math level,” one sniffed.

    In 2016, Hurlburt and a friend, Rich Geldreich, founded a start-up called Binomial, where they created software that helps compress the size of “textures” in graphics-heavy software. Being self-employed, she figured, would mean not having to deal with belittling bosses. But when she and Geldreich went to sell their product, some customers assumed that she was just the marketing person. “I don’t know how you got this product off the ground when you only have one programmer!” she recalls one client telling Geldreich.

    In 2014, an informal analysis by a tech entrepreneur and former academic named Kieran Snyder of 248 corporate performance reviews for tech engineers determined that women were considerably more likely than men to receive reviews with negative feedback; men were far more likely to get reviews that had only constructive feedback, with no negative material. In a 2016 experiment conducted by the tech recruiting firm Speak With a Geek, 5,000 résumés with identical information were submitted to firms. When identifying details were removed from the résumés, 54 percent of the women received interview offers; when gendered names and other biographical information were given, only 5 percent of them did.

    Lurking beneath some of this sexist atmosphere is the phantasm of sociobiology. As this line of thinking goes, women are less suited to coding than men because biology better endows men with the qualities necessary to excel at programming. Many women who work in software face this line of reasoning all the time. Cate Huston, a software engineer at Google from 2011 to 2014, heard it from colleagues there when they pondered why such a low percentage of the company’s programmers were women. Peers would argue that Google hired only the best — that if women weren’t being hired, it was because they didn’t have enough innate logic or grit, she recalls.

    In the summer of 2017, a Google employee named James Damore suggested in an internal email that several qualities more commonly found in women — including higher rates of anxiety — explained why they weren’t thriving in a competitive world of coding; he cited the cognitive neuroscientist Simon Baron-Cohen, who theorizes that the male brain is more likely to be “systemizing,” compared with women’s “empathizing” brains. Google fired Damore, saying it could not employ someone who would argue that his female colleagues were inherently unsuited to the job. But on Google’s internal boards, other male employees backed up Damore, agreeing with his analysis. The assumption that the makeup of the coding work force reflects a pure meritocracy runs deep among many Silicon Valley men; for them, sociobiology offers a way to explain things, particularly for the type who prefers to believe that sexism in the workplace is not a big deal, or even doubts it really exists.

    But if biology were the reason so few women are in coding, it would be impossible to explain why women were so prominent in the early years of American programming, when the work could be, if anything, far harder than today’s programming. It was an uncharted new field, in which you had to do math in binary and hexadecimal formats, and there were no helpful internet forums, no Google to query, for assistance with your bug. It was just your brain in a jar, solving hellish problems.

    If biology limited women’s ability to code, then the ratio of women to men in programming ought to be similar in other countries. It isn’t. In India, roughly 40 percent of the students studying computer science and related fields are women. This is despite even greater barriers to becoming a female coder there; India has such rigid gender roles that female college students often have an 8 p.m. curfew, meaning they can’t work late in the computer lab, as the social scientist Roli Varma learned when she studied them in 2015. The Indian women had one big cultural advantage over their American peers, though: They were far more likely to be encouraged by their parents to go into the field, Varma says. What’s more, the women regarded coding as a safer job because it kept them indoors, lessening their exposure to street-level sexual harassment. It was, in other words, considered normal in India that women would code. The picture has been similar in Malaysia, where in 2001 — precisely when the share of American women in computer science had slid into a trough — women represented 52 percent of the undergraduate computer-science majors and 39 percent of the Ph.D. candidates at the University of Malaya in Kuala Lumpur.

    Today, when midcareer women decide that Silicon Valley’s culture is unlikely to change, many simply leave the industry. When Sue Gardner surveyed those 1,400 women in 2014, they told her the same story: In the early years, as junior coders, they looked past the ambient sexism they encountered. They loved programming and were ambitious and excited by their jobs. But over time, Gardner says, “they get ground down.” As they rose in the ranks, they found few, if any, mentors. Nearly two-thirds either experienced or witnessed harassment, she read in “The Athena Factor” (a 2008 study of women in tech); in Gardner’s survey, one-third reported that their managers were more friendly toward and gave more support to their male co-workers. It’s often assumed that having children is the moment when women are sidelined in tech careers, as in many others, but Gardner discovered that wasn’t often the breaking point for these women. They grew discouraged seeing men with no better or even lesser qualifications get superior opportunities and treatment.

    “What surprised me was that they felt, ‘I did all that work!’ They were angry,” Gardner says. “It wasn’t like they needed a helping hand or needed a little extra coaching. They were mad. They were not leaving because they couldn’t hack it. They were leaving because they were skilled professionals who had skills that were broadly in demand in the marketplace, and they had other options. So they’re like, ‘[expletive] it — I’ll go somewhere where I’m seen as valuable.’ ”

    The result is an industry that is drastically more male than it was decades ago, and far more so than the workplace at large. In 2018, according to data from the Bureau of Labor Statistics, about 26 percent of the workers in “computer and mathematical occupations” were women. The percentages for people of color are similarly low: Black employees were 8.4 percent, Latinos 7.5 percent. (The Census Bureau’s American Community Survey put black coders at only 4.7 percent in 2016.) In the more rarefied world of the top Silicon Valley tech firms, the numbers are even more austere: A 2017 analysis by Recode, a news site that covers the technology industry, revealed that 20 percent of Google’s technical employees were women, while only 1 percent were black and 3 percent were Hispanic. Facebook was nearly identical; the numbers at Twitter were 15 percent, 2 percent and 4 percent, respectively.

    The reversal has been profound. In the early days of coding, women flocked to programming because it offered more opportunity and reward for merit, more than fields like law. Now software has the closed door.

    In the late 1990s, Allan Fisher decided that Carnegie Mellon would try to address the male-female imbalance in its computer-science program. Prompted by Jane Margolis’s findings, Fisher and his colleagues instituted several changes. One was the creation of classes that grouped students by experience: The kids who had been coding since youth would start on one track; the newcomers to coding would have a slightly different curriculum, allowing them more time to catch up. Carnegie Mellon also offered extra tutoring to all students, which was particularly useful for the novice coders. If Fisher could get them to stay through the first and second years, he knew, they would catch up to their peers.

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    Components from four of the earliest electronic computers, held by Patsy Boyce Simmers, Gail Taylor, Millie Beck and Norma Stec, employees at the United States Army’s Ballistics Research Laboratory.Credit Science Source

    They also modified the courses in order to show how code has impacts in the real world, so a new student’s view of programming wouldn’t just be an endless vista of algorithms disconnected from any practical use. Fisher wanted students to glimpse, earlier on, what it was like to make software that works its way into people’s lives. Back in the ’90s, before social media and even before the internet had gone mainstream, the influence that code could have on daily life wasn’t so easy to see.

    Faculty members, too, adopted a different perspective. For years some had tacitly endorsed the idea that the students who came in already knowing code were born to it. Carnegie Mellon “rewarded the obsessive hacker,” Fisher told me. But the faculty now knew that their assumptions weren’t true; they had been confusing previous experience with raw aptitude. They still wanted to encourage those obsessive teenage coders, but they had come to understand that the neophytes were just as likely to bloom rapidly into remarkable talents and deserved as much support. “We had to broaden how faculty sees what a successful student looks like,” he says. The admissions process was adjusted, too; it no longer gave as much preference to students who had been teenage coders.

    No single policy changed things. “There’s really a virtuous cycle,” Fisher says. “If you make the program accommodate people with less experience, then people with less experience come in.” Faculty members became more used to seeing how green coders evolve into accomplished ones, and they learned how to teach that type.

    Carnegie Mellon’s efforts were remarkably successful. Only a few years after these changes, the percentage of women entering its computer-science program boomed, rising to 42 percent from 7 percent; graduation rates for women rose to nearly match those of the men. The school vaulted over the national average. Other schools concerned about the low number of female students began using approaches similar to Fisher’s. In 2006, Harvey Mudd College tinkered with its Introduction to Computer Science course, creating a track specifically for novices, and rebranded it as Creative Problem Solving in Science and Engineering Using Computational Approaches — which, the institution’s president, Maria Klawe, told me, “is actually a better description of what you’re actually doing when you’re coding.” By 2018, 54 percent of Harvey Mudd’s graduates who majored in computer science were women.

    A broader cultural shift has accompanied the schools’ efforts. In the last few years, women’s interest in coding has begun rapidly rising throughout the United States. In 2012, the percentage of female undergraduates who plan to major in computer science began to rise at rates not seen for 35 years [Computing Research News], since the decline in the mid-’80s, according to research by Linda Sax, an education professor at U.C.L.A. There has also been a boomlet of groups and organizations training and encouraging underrepresented cohorts to enter the field, like Black Girls Code and Code Newbie. Coding has come to be seen, in purely economic terms, as a bastion of well-paying and engaging work.

    In an age when Instagram and Snapchat and iPhones are part of the warp and weft of life’s daily fabric, potential coders worry less that the job will be isolated, antisocial and distant from reality. “Women who see themselves as creative or artistic are more likely to pursue computer science today than in the past,” says Sax, who has pored over decades of demographic data about the students in STEM fields. They’re still less likely to go into coding than other fields, but programming is increasingly on their horizon. This shift is abetted by the fact that it’s much easier to learn programming without getting a full degree, through free online coding schools, relatively cheaper “boot camps” or even meetup groups for newcomers — opportunities that have emerged only in the last decade.

    Changing the culture at schools is one thing. Most female veterans of code I’ve spoken to say that what is harder is shifting the culture of the industry at large, particularly the reflexive sexism and racism still deeply ingrained in Silicon Valley. Some, like Sue Gardner, sometimes wonder if it’s even ethical for her to encourage young women to go into tech. She fears they’ll pour out of computer-science programs in increasing numbers, arrive at their first coding job excited and thrive early on, but then gradually get beaten down by industry. “The truth is, we can attract more and different people into the field, but they’re just going to hit that wall in midcareer, unless we change how things happen higher up,” she says.

    On a spring weekend in 2017, more than 700 coders and designers were given 24 hours to dream up and create a new product at a hackathon in New York hosted by TechCrunch, a news site devoted to technology and Silicon Valley. At lunchtime on Sunday, the teams presented their creations to a panel of industry judges, in a blizzard of frantic elevator pitches. There was Instagrammie, a robot system that would automatically recognize the mood of an elderly relative or a person with limited mobility; there was Waste Not, an app to reduce food waste. Most of the contestants were coders who worked at local high-tech firms or computer-science students at nearby universities.

    6
    Despite women’s historical role in the vanguard of computer programing, some female veterans of code wonder if it’s even ethical to encourage young women to go into tech because of the reflexive sexism in the current culture of Silicon Valley.CreditApic/Getty Images

    The winning team, though, was a trio of high school girls from New Jersey: Sowmya Patapati, Akshaya Dinesh and Amulya Balakrishnan. In only 24 hours, they created reVIVE, a virtual-reality app that tests children for signs of A.D.H.D. After the students were handed their winnings onstage — a trophy-size check for $5,000 — they flopped into chairs in a nearby room to recuperate. They had been coding almost nonstop since noon the day before and were bleary with exhaustion.

    “Lots of caffeine,” Balakrishnan, 17, said, laughing. She wore a blue T-shirt that read WHO HACK THE WORLD? GIRLS. The girls told me that they had impressed even themselves by how much they accomplished in 24 hours. “Our app really does streamline the process of detecting A.D.H.D.,” said Dinesh, who was also 17. “It usually takes six to nine months to diagnose, and thousands of dollars! We could do it digitally in a much faster way!”

    They all became interested in coding in high school, each of them with strong encouragement from immigrant parents. Balakrishnan’s parents worked in software and medicine; Dinesh’s parents came to the United States from India in 2000 and worked in information technology. Patapati immigrated from India as an infant with her young mother, who never went to college, and her father, an information-tech worker who was the first in his rural family to go to college.

    Drawn to coding in high school, the young hackers got used to being the lone girl nerds at school, as Dinesh told me.

    “I tried so hard to get other girls interested in computer science, and it was like, the interest levels were just so low,” she says. “When I walked into my first hackathon, it was the most intimidating thing ever. I looked at a room of 80 kids: Five were girls, and I was probably the youngest person there.” But she kept on competing in 25 more hackathons, and her confidence grew. To break the isolation and meet more girls in coding, she attended events by organizations like #BuiltByGirls, which is where, a few days previously, she had met Patapati and Balakrishnan and where they decided to team up. To attend TechCrunch, Patapati, who was 16, and Balakrishnan skipped a junior prom and a friend’s birthday party. “Who needs a party when you can go to a hackathon?” Patapati said.

    Winning TechCrunch as a group of young women of color brought extra attention, not all of it positive. “I’ve gotten a lot of comments like: ‘Oh, you won the hackathon because you’re a girl! You’re a diversity pick,” Balakrishnan said. After the prize was announced online, she recalled later, “there were quite a few engineers who commented, ‘Oh, it was a girl pick; obviously that’s why they won.’ ”

    Nearly two years later, Balakrishnan was taking a gap year to create a heart-monitoring product she invented, and she was in the running for $100,000 to develop it. She was applying to college to study computer science and, in her spare time, competing in a beauty pageant, inspired by Miss USA 2017, Kara McCullough, who was a nuclear scientist. “I realized that I could use pageantry as a platform to show more girls that they could embrace their femininity and be involved in a very technical, male-dominated field,” she says. Dinesh, in her final year at high school, had started an all-female hackathon that now takes place annually in New York. (“The vibe was definitely very different,” she says, more focused on training newcomers.)

    Patapati and Dinesh enrolled at Stanford last fall to study computer science; both are interested deeply in A.I. They’ve noticed the subtle tensions for women in the coding classes. Patapati, who founded a Women in A.I. group with an Apple tech lead, has watched as male colleagues ignore her raised hand in group discussions or repeat something she just said as if it were their idea. “I think sometimes it’s just a bias that people don’t even recognize that they have,” she says. “That’s been really upsetting.”

    Dinesh says “there’s absolutely a difference in confidence levels” between the male and female newcomers. The Stanford curriculum is so intense that even the relative veterans like her are scrambling: When we spoke recently, she had just spent “three all-nighters in a row” on a single project, for which students had to engineer a “print” command from scratch. At 18, she has few illusions about the road ahead. When she went to a blockchain conference, it was a sea of “middle-aged white and Asian men,” she says. “I’m never going to one again,” she adds with a laugh.

    “My dream is to work on autonomous driving at Tesla or Waymo or some company like that. Or if I see that there’s something missing, maybe I’ll start my own company.” She has begun moving in that direction already, having met one venture capitalist via #BuiltByGirls. “So now I know I can start reaching out to her, and I can start reaching out to other people that she might know,” she says.

    Will she look around, 20 years from now, to see that software has returned to its roots, with women everywhere? “I’m not really sure what will happen,” she admits. “But I do think it is absolutely on the upward climb.”

    Correction: Feb. 14, 2019
    An earlier version of this article misidentified the institution Ellen Spertus was affiliated with when she published a 1991 report on women’s experiences in programming classes. Spertus was at M.I.T. when she published the report, not Mills College, where she is currently a professor.

    Correction: Feb. 14, 2019
    An earlier version of this article misstated Akshaya Dinesh’s current age. She is 18, not 19.

    See the full article here .

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  • richardmitnick 8:14 pm on February 15, 2019 Permalink | Reply
    Tags: "Looking Forward to Fusion", Applied Research & Technology, , , MIT Spectrum, Patrick White,   

    From MIT Spectrum: “Looking Forward to Fusion” 

    MIT Widget

    From MIT Spectrum

    Winter 2019

    1
    Patrick White (photographed in the Plasma Science and Fusion Center) is focused on the policy questions that will arise from the new SPARC technology. Photo: Bryce Vickmark

    Technical policy scholar Patrick White joins the SPARC project to ask: what comes after success?

    Controlled fusion power has been a tantalizing prospect for decades, promising a source of endless carbon-free energy for the world. Unfortunately, persistent technical challenges have kept that achievement on an ever-receding horizon. But recent developments in materials science and superconductivity have changed the landscape. The proposed SPARC experiment of MIT’s Plasma Science and Fusion Center (PSFC), in collaboration with the private, MIT alumni-led company Commonwealth Fusion Systems, is poised to use those breakthroughs to build the first fusion device that generates more energy than it consumes, bringing commercial fusion energy within practical reach in the near future.

    MIT SPARC fusion reactor tokamak

    Patrick White, a PhD candidate in the Department of Nuclear Science and Engineering (NSE), is looking ahead to that long-awaited day. His PhD project, funded by the Samuel W. Ing (1953) Memorial Fellowship in the NSE department and PSFC, anticipates the many questions that will follow a successful SPARC project and the development of fusion power.

    “How do you commercialize this technology that no one’s ever built before?” he asks. “It’s an opportunity to start from scratch.” White is focusing on the regulatory structures and safety analysis tools that will be necessary to bring fusion power plants out of the laboratory and onto the national power grid.

    He first became fascinated with nuclear science and technology while studying mechanical engineering at Carnegie Mellon University. “I think it was the fact that you can take a gram of uranium and release the same energy as several tons worth of coal, or that a single nuclear reactor can power a million homes for 60 years,” he remembers. “That absolutely blew me away.” He saw commercial reactor technology up close during an undergraduate summer internship with Westinghouse, and followed that with two summers in Washington, DC, working with the Defense Nuclear Facilities Safety Board.

    When White came to MIT for graduate work, he joined the MIT Energy Initiative’s major interdisciplinary study, The Future of Nuclear Energy in a Carbon-Constrained World, authoring the regulation and licensing section of the final report (which was subsequently released this past September). He began casting about for a PhD topic around the time the SPARC project was announced.

    The goal of SPARC is to demonstrate net energy from a fusion device in seven years—a key technical milestone that could lead to the construction of a commercially viable power plant scaled up to roughly twice SPARC’s diameter. Because the fusion process produces net energy at extreme temperatures no solid material can withstand, fusion researchers use magnetic fields to keep the hot plasma from coming into contact with the device’s chamber. Currently, the team building SPARC is refining the superconducting magnet technology that will be central to its operation. Already familiar with the regulatory and safety framework that’s been developed over decades of commercial fission reactor operation, White immediately began considering the challenges of regulating an entirely new potential technology that hasn’t yet been invented. One concern in the fusion community, he notes, is that “before we even have a final plant design, the regulatory system could make the ultimate device too expensive or too cumbersome to actually operate. So we’ll be looking at existing nuclear and non-nuclear industries, how they think about safety and regulation, and trying to come up with a pathway that makes the most sense for this new technology.”

    His PhD project proposal on the regulation of commercial fusion plants was selected by the PSFC for funding, and he got down to work in fall 2018 under three advisors: Zach Hartwig PhD ’14, the John C. Hardwick Assistant Professor of Nuclear Science and Engineering; assistant professor Koroush Shirvan SM ’10, PhD ’13; and Dennis Whyte, director of PSFC and the Hitachi America Professor of Engineering.

    White’s career plans beyond the fellowship remain flexible: he notes that whether he ends up working with the licensing of advanced fission reactors or in the new world of commercial fusion power will depend on the technology itself, and how SPARC and other experimental projects evolve. Another possibility is bridging the communications gap between the nuclear industry and a public that’s often apprehensive about nuclear technology: “At the end of the day, if people refuse to have it built in their backyard, you’ve got a great device that can’t actually do any good.”

    For now, White’s fellowship is not only laying the groundwork for his own future, but also perhaps the future of what would be one of the greatest technological advances of humankind. He points out that the stakes are higher than simply developing a new energy technology. “If we’re really concerned about climate change and decarbonizing, we need to have every single tool on the table,” he says. “The more tools, the better.”

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    MIT Seal

    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

    MIT Campus

     
  • richardmitnick 4:24 pm on February 15, 2019 Permalink | Reply
    Tags: "Tiny particles can switch back and forth between phases", Applied Research & Technology, Cornell High Energy Synchrotron Source, Inorganic isomerization, Isomerization – the transformation of a molecule into another molecule with the same atoms just in a different arrangement, ,   

    From Cornell Chronicle: “Tiny particles can switch back and forth between phases” 

    Cornell Bloc

    From Cornell Chronicle

    February 14, 2019
    Melanie Lefkowitz

    Three years ago, when Richard Robinson, associate professor of materials science and engineering, was on sabbatical at Hebrew University in Israel, he asked a graduate student to send him some nanoparticles of a specific size.

    “When they got to me, I measured them with the spectrometer and I said, ‘Wait, you sent me the smaller particles instead of the bigger ones.’ And he said, ‘No, I sent you the bigger ones,’” recalls Robinson, of his conversation with his advisee Curtis Williamson, a doctoral student in chemical and biomolecular engineering. “We realized they must have changed while they were in flight. And that unleashed a cascade of questions and experiments that led us to this new finding.”

    They deduced that the particles had transformed during their trip from Ithaca to Jerusalem. This realization led to the discovery of inorganic isomerization, in which inorganic materials are able switch between discrete states almost instantaneously – faster than the speed of sound. The finding bridges the gap between what’s known about phase changes in organic molecules, such as those that make eyesight possible, and in bulk materials, like the transition of graphite into diamonds.

    Their find was surprising because it implied that inorganic materials could transform like organic molecules, said Robinson, co-author of the paper, “Chemically Reversible Isomerization of Inorganic Clusters,” which published Feb. 15 in Science.

    “We found that if you shrink inorganic material small enough, it can easily jump back and forth between two discrete phases, initiated by small amounts of alcohol or moisture on the surface,” Robinson said. “On the flight there must have been moisture in the cargo bin, and the samples switched their phase.”

    Williamson is the paper’s first author. Senior authors are Robinson; Tobias Hanrath, associate professor at the Smith School of Chemical and Biomolecular Engineering; and Uri Banin, professor of chemistry at Hebrew University. Douglas Nevers, Ph.D. ’18, Andrew Nelson, doctoral student in materials science and engineering, and Ido Hadar of Hebrew University also contributed.

    “We bridged the two worlds between big materials that change more slowly, and small, organic materials that can flip back and forth coherently, between two states,” Robinson said. “It’s surprising that we saw an instantaneous transformation from one state to another in an inorganic material, and it’s surprising that it is initiated with a simple surface reaction.”

    Isomerization – the transformation of a molecule into another molecule with the same atoms, just in a different arrangement – is common in nature. Often it’s sparked by the addition of energy, as when light causes a molecule in the retina to switch, enabling vision; or how olive oil, when heated too high, isomerizes into the unhealthy form known as a trans-fat. Bulk materials such as graphite can also change phases, but they require a lot more energy than at the molecular level and the change occurs more gradually, with the change spreading across the substance rather than an instantaneous transformation.

    In the past, larger nanoparticles were found to change phases in a way that was closer to how bulk materials change than to molecules. But when the Cornell team looked at even smaller clusters of atoms at the Cornell High Energy Synchrotron Source (CHESS), they observed the quick change between discrete states for the first time.

    Cornell High Energy Synchrotron Source

    “We now finally see that there’s a new regime where you can coherently flip from one state to another instantaneously,” Hanrath said. “If you make them small enough, the inorganic materials can flip back and forth very easily. It’s a revelation.”

    Robinson said the researchers would not have been able to precisely determine atoms’ positions without CHESS, where they performed total-scattering experiments in which they examined all the X-ray scatterings of the cluster, enabling them to pinpoint the locations of the atoms.

    They were also aided by a new technique they developed to create magic-sized clusters – so-called because they have the “perfect” number of atoms and no more individual atoms can be added, making them extremely stable.

    “We were able to come up with a very pure magic-sized cluster,” Robinson said. “Because of that, when it reacts with the alcohol or water you see a very pure transformation” from one discrete state to another.

    Though further research is needed, possible future applications include using these particles as switches in computing or as sensors, Robinson said. The discovery could also have uses relating to quantum computing or as a seed for the generation of larger nanoparticles.

    The work was supported by the National Science Foundation and made use of the Cornell Center for Materials Research Shared Facilities and CHESS, which both receive funding from the NSF. The researchers also received funding from the European Research Council, Hebrew University and the U.S. Fulbright Scholar Program.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Once called “the first American university” by educational historian Frederick Rudolph, Cornell University represents a distinctive mix of eminent scholarship and democratic ideals. Adding practical subjects to the classics and admitting qualified students regardless of nationality, race, social circumstance, gender, or religion was quite a departure when Cornell was founded in 1865.

    Today’s Cornell reflects this heritage of egalitarian excellence. It is home to the nation’s first colleges devoted to hotel administration, industrial and labor relations, and veterinary medicine. Both a private university and the land-grant institution of New York State, Cornell University is the most educationally diverse member of the Ivy League.

    On the Ithaca campus alone nearly 20,000 students representing every state and 120 countries choose from among 4,000 courses in 11 undergraduate, graduate, and professional schools. Many undergraduates participate in a wide range of interdisciplinary programs, play meaningful roles in original research, and study in Cornell programs in Washington, New York City, and the world over.

     
  • richardmitnick 11:20 am on February 15, 2019 Permalink | Reply
    Tags: "Physicists create a quantum refrigerator that cools with an absence of light", Applied Research & Technology, , , Near-field photonic cooling through control of the chemical potential of photons, , , ,   

    From U Michigan via Science Magazine: “Physicists create a quantum refrigerator that cools with an absence of light” 

    U Michigan bloc

    From University of Michigan

    via

    AAAS
    Science Magazine

    Feb. 14, 2019
    Daniel Garisto

    1
    This new device shows that an LED can cool other tiny objects. Joseph Xu/Michigan Engineering, Communications & Marketing

    For decades, atomic physicists have used laser light to slow atoms zinging around in a gas, cooling them to just above absolute zero to study their weird quantum properties. Now, a team of scientists has managed to similarly cool an object—but with the absence of light rather than its presence. The technique, which has never before been experimentally shown, might someday be used to chill the components in microelectronics.

    In an ordinary laser cooling experiment, physicists shine laser light from opposite directions—up, down, left, right, front, back—on a puff of gas such as rubidium. They tune the lasers precisely, so that if an atom moves toward one of them, it absorbs a photon and gets a gentle push back toward the center. Set it up just right and the light saps away the atoms’ kinetic energy, cooling the gas to a very low temperature.

    But Pramod Reddy, an applied physicist at the University of Michigan in Ann Arbor, wanted to try cooling without the special properties of laser light. He and colleagues started with a widget made of semiconducting material commonly found in video screens—a light-emitting diode (LED). An LED exploits a quantum mechanical effect to turn electrical energy into light. Roughly speaking, the LED acts like a little ramp for electrons. Apply a voltage in the right direction and it pushes electrons up and over the ramp, like kids on skateboards. As electrons fall over the ramp to a lower energy state, they emit photons.

    Crucially for the experiment, the LED emits no light when the voltage is reversed, as the electrons cannot go over the ramp in the opposite direction. In fact, reversing the voltage also suppresses the device’s infrared radiation—the broad spectrum of light (including heat) that you see when you look at a hot object through night vision goggles.

    That effectively makes the device colder—and it means the little thing can work like a microscopic refrigerator, Reddy says. All that’s necessary is to put it close enough to another tiny object, he says. “If you take a hot object and a cold object … you can have a radiative exchange of heat,” Reddy says. To prove that they could use an LED to cool, the scientists placed one just tens of nanometers—the width of a couple hundred atoms—away from a heat-measuring device called a calorimeter. That was close enough to increase the transfer of photons between the two objects, due to a process called quantum tunneling. Essentially, the gap was so small that photons could sometimes hop over it.

    The cooler LED absorbed more photons from the calorimeter than it gave back to it, wicking heat away from the calorimeter and lowering its temperature by a ten-thousandth of a degree Celsius, Reddy and colleagues report this week in Nature. That’s a small change, but given the tiny size of the LED, it equals an energy flux of 6 watts per square meter. For comparison, the sun provides about 1000 watts per square meter. Reddy and his colleagues believe they could someday increase the cooling flux up to that strength by reducing the gap size and siphoning away the heat that builds up in the LED.

    The technique probably won’t replace traditional refrigeration techniques or be able to cool materials below temperatures of about 60 K. But it has the potential to someday be used for cooling microelectronics, according to Shanhui Fan, a theoretical physicist at Stanford University in Palo Alto, California, who was not involved with the work. In earlier work, Fan used computer modeling to predict that an LED could have a sizeable cooling effect if placed nanometers from another object. Now, he said, Reddy and his team have realized that idea experimentally.

    See the full article here .


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    Please support STEM education in your local school system

    Stem Education Coalition

    U MIchigan Campus

    The University of Michigan (U-M, UM, UMich, or U of M), frequently referred to simply as Michigan, is a public research university located in Ann Arbor, Michigan, United States. Originally, founded in 1817 in Detroit as the Catholepistemiad, or University of Michigania, 20 years before the Michigan Territory officially became a state, the University of Michigan is the state’s oldest university. The university moved to Ann Arbor in 1837 onto 40 acres (16 ha) of what is now known as Central Campus. Since its establishment in Ann Arbor, the university campus has expanded to include more than 584 major buildings with a combined area of more than 34 million gross square feet (781 acres or 3.16 km²), and has two satellite campuses located in Flint and Dearborn. The University was one of the founding members of the Association of American Universities.

    Considered one of the foremost research universities in the United States,[7] the university has very high research activity and its comprehensive graduate program offers doctoral degrees in the humanities, social sciences, and STEM fields (Science, Technology, Engineering and Mathematics) as well as professional degrees in business, medicine, law, pharmacy, nursing, social work and dentistry. Michigan’s body of living alumni (as of 2012) comprises more than 500,000. Besides academic life, Michigan’s athletic teams compete in Division I of the NCAA and are collectively known as the Wolverines. They are members of the Big Ten Conference.

     
  • richardmitnick 10:28 am on February 15, 2019 Permalink | Reply
    Tags: , Applied Research & Technology, , Researchers create ultra-lightweight ceramic material that can better withstand extreme temperatures, Ceramics   

    From UCLA Newsroom: “Researchers create ultra-lightweight ceramic material that can better withstand extreme temperatures” 


    From UCLA Newsroom

    February 14, 2019
    Matthew Chin

    UCLA-led team develops highly durable aerogel that could ultimately be an upgrade for insulation on spacecraft.

    1
    The new ceramic aerogel is so lightweight that it can rest on a flower without damaging it. Xiangfeng Duan and Xiang Xu/UCLA

    UCLA researchers and collaborators at eight other research institutions have created an extremely light, very durable ceramic aerogel. The material could be used for applications like insulating spacecraft because it can withstand the intense heat and severe temperature changes that space missions endure.

    Ceramic aerogels have been used to insulate industrial equipment since the 1990s, and they have been used to insulate scientific equipment on NASA’s Mars rover missions. But the new version is much more durable after exposure to extreme heat and repeated temperature spikes, and much lighter. Its unique atomic composition and microscopic structure also make it unusually elastic.

    When it’s heated, the material contracts rather than expanding like other ceramics do. It also contracts perpendicularly to the direction that it’s compressed — imagine pressing a tennis ball on a table and having the center of the ball move inward rather than expanding out — the opposite of how most materials react when compressed. As a result, the material is far more flexible and less brittle than current state-of-the-art ceramic aerogels: It can be compressed to 5 percent of its original volume and fully recover, while other existing aerogels can be compressed to only about 20 percent and then fully recover.

    The research, which was published today in Science, was led by Xiangfeng Duan, a UCLA professor of chemistry and biochemistry; Yu Huang, a UCLA professor of materials science and engineering; and Hui Li of Harbin Institute of Technology, China. The study’s first authors are Xiang Xu, a visiting postdoctoral fellow in chemistry at UCLA from Harbin Institute of Technology; Qiangqiang Zhang of Lanzhou University; and Menglong Hao of UC Berkeley and Southeast University.

    Other members of the research team were from UC Berkeley; Purdue University; Lawrence Berkeley National Laboratory; Hunan University, China; Lanzhou University, China; and King Saud University, Saudi Arabia.

    Despite the fact that more than 99 percent of their volume is air, aerogels are solid and structurally very strong for their weight. They can be made from many types of materials, including ceramics, carbon or metal oxides. Compared with other insulators, ceramic-based aerogels are superior in blocking extreme temperatures, and they have ultralow density and are highly resistant to fire and corrosion — all qualities that lend themselves well to reusable spacecraft.

    But current ceramic aerogels are highly brittle and tend to fracture after repeated exposure to extreme heat and dramatic temperature swings, both of which are common in space travel.

    The new material is made of thin layers of boron nitride, a ceramic, with atoms that are connected in hexagon patterns, like chicken wire.

    In the UCLA-led research, it withstood conditions that would typically fracture other aerogels. It stood up to hundreds of exposures to sudden and extreme temperature spikes when the engineers raised and lowered the temperature in a testing container between minus 198 degrees Celsius and 900 degrees above zero over just a few seconds. In another test, it lost less than 1 percent of its mechanical strength after being stored for one week at 1,400 degrees Celsius.

    “The key to the durability of our new ceramic aerogel is its unique architecture,” Duan said. “Its innate flexibility helps it take the pounding from extreme heat and temperature shocks that would cause other ceramic aerogels to fail.”

    2
    Breath mint-sized samples of the ceramic aerogels developed by a UCLA-led research team. The material is 99 percent air by volume, making it super lightweight. Oszie Tarula/UCLA

    Ordinary ceramic materials usually expand when heated and contract when they are cooled. Over time, those repeated temperature changes can lead those materials to fracture and ultimately fail. The new aerogel was designed to be more durable by doing just the opposite — it contracts rather than expanding when heated.

    In addition, the aerogel’s ability to contract perpendicularly to the direction that it’s being compressed — like the tennis ball example — help it survive repeated and rapid temperature changes. (That property is known as a negative Poisson’s ratio.) It also has interior “walls” that are reinforced with a double-pane structure, which cuts down the material’s weight while increasing its insulating abilities.

    Duan said the process researchers developed to make the new aerogel also could be adapted to make other ultra-lightweight materials.

    “Those materials could be useful for thermal insulation in spacecraft, automobiles or other specialized equipment,” he said. “They could also be useful for thermal energy storage, catalysis or filtration.”

    The research was partly supported by grants from the National Science Foundation.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 1:58 pm on February 14, 2019 Permalink | Reply
    Tags: A design history from the Tevatron's CDF and DZero, Applied Research & Technology, , , Muon tomography   

    From Fermi National Accelerator Lab: “Using Fermilab detector expertise for award-winning project success” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    February 13, 2019
    Ron Lipton

    1
    Fermilab and the Nevada National Security Site designed this award-winning silicon strip detectors to be used for muon tomography. Muon tomography takes advantage of muons’ ability to traverse solid objects to view what’s inside them, much like an X-ray machine. Photo: Ron Lipton

    The recent R&D 100 Award given to the Fermilab and the Nevada National Security Site’s Remote Sensing Laboratory (RSL) is an example of how the depth of experience and infrastructure at the lab can enable an efficient approach to innovative projects. Andrew Green of RSL, who had earned his Ph.D. working on the DZero experiment at the Tevatron, approached me about collaborating on a demonstration of a silicon tracking system that could be used for muon tomography, providing a more compact and maintainable system than the current approach, which uses drift tubes.

    Muon tomography takes advantage of muons’ ability to traverse solid objects to view what’s inside them, much like an X-ray machine. Our group was in a period between large projects when resources were available, and the laboratory agreed to work with RSL. We formed a collaboration where Fermilab provided the mechanical and electrical design and assembly work, and the Remote Sensing Laboratory provided simulation, overall design, analysis software and funding.

    Fermilab has enormous experience in building silicon detectors, starting with fixed-target experiments that demonstrated the technology in the 1980s, through the CDF and DZero vertex detectors, followed by the CMS outer tracker and pixel detectors. Because of this, we were able to quickly put together a design that made efficient use of both people and materials.

    We chose sensors we had “on the shelf” that were rejected by CMS because of production flaws but were adequate for a technology demonstration. These sensors set the scale and characteristics of the planes to be produced. Greg Selberg built some early design prototypes. Bill Cooper, a physicist who led the DZero silicon detector mechanical design, came out of retirement to work part-time to design the planes and associated support structure. A crucial part of the design was the carbon fiber support structure with embedded copper that acts both as a support and a ground plane following a technique pioneered in DZero layer 0. The carbon fiber structure and other support parts were fabricated by Dave Butler, Otto Alvarez and his group in the PPD mechanical shop, based on their long experience of carbon fiber fabrication.

    At that time Paul Rubinov’s group in PPD Electrical Engineering was supporting CMS high-granularity calorimeter (HGCAL) test beam prototypes. They had developed hardware and software to read out HGCAL modules in the test beam with what’s called a SKIROC chip. We chose to use that chip for the muon tomography project to take advantage of the design expertise and software experience in Paul’s group. Paul developed the conceptual design of the system. Cristian Gingu adapted and refined his SKIROC readout firmware for the muon application. Mike Utes designed the readout boards, debugged the overall system, and managed the day-to-day production and testing work. Johnny Green managed parts procurement. Other boards were adapted from parts designed by the University of Minnesota for the HGCAL testing.

    The actual assembly was done at SiDet. Bert Gonzalez, who has been a part of the CDF, DZero, CMS and many other construction projects, provided the precision assembly of the planes. He was able to achieve a precision of 10 microns without the use of specialized jigs or fixtures. Michelle Jonas and Tammy Hawke provided the precision wire bonding of the large area sensors to each other and to the readout board. Vale Glasser and Rich Prokop, summer students from the Community College Internship program, worked during the last two summers to test and analyze data from the assembled devices.

    As you can see, this work was a real team effort. It is a team with levels of experience and capabilities that lead the world. That such people were available is the result of more than 30 years of detector design, assembly and testing at the laboratory. We are fortunate to have people with this level of experience, knowledge and breadth of skill available at Fermilab.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 11:12 am on February 14, 2019 Permalink | Reply
    Tags: Applied Research & Technology, , ESA probing into post-silicon wide bandgap landscape, Gallium nitride, Raising interest in a new range of ‘wide bandgap’ semiconductor materials   

    From European Space Agency: “ESA probing into post-silicon, wide bandgap landscape” 

    ESA Space For Europe Banner

    From European Space Agency

    13 February 2019
    1
    Crystal of gallium nitride

    What comes next after silicon? Some seven decades from the invention of the silicon chip this question is often asked, especially in the space sector: demands for extreme high performance have highlighted silicon’s inherent limitations, raising interest in a new range of ‘wide bandgap’ semiconductor materials.

    A material’s ‘bandgap’ is the space between atomic shell layers that dictates the amount of energy needed to get electrons moving and make that material conductive. But electrons can also be shifted into the conduction band by heat; so, for instance, silicon-based semiconductors become unusable for temperatures from around 180°C and up.

    Wide bandgap materials such as gallium nitride, silicon carbide and diamond can attain much higher operating temperatures, potentially enabling much higher current density designs running at higher voltages. Electrons also move faster through them, delivering faster device speeds. And as an added benefit they are robust against the effects of radiation – a particular issue in space.

    2
    GaN on silicon carbide wafers, produced as part of ESA’s GREAT2 project

    ESA recognised the potential of the wide bandgap realm for space at an early stage, founding the ‘GaN Reliability Enhancement and Technology Transfer Initiative’ (GREAT2) in 2008 for gallium nitride (GaN) microwave devices, at a time when it was used mainly for high-performance LEDs and the lasers of Blu-ray players.

    Leading research institutes were brought together with manufacturers to set up an independent European supply chain to manufacture high-quality GaN radio frequency devices for space applications.

    3
    GaN wafer quality check

    “The promise of these materials makes them highly strategic,” explains Andrew Barnes, heading GREAT2. “We need independent European supply chains because if we were totally dependent on a foreign source that became subject to export restrictions then the whole industrial sector would be compromised, along with our competitiveness.”

    The initial focus of GREAT2 was on GaN-based microwave power transistors and integrated circuits, as building blocks for high-performance solid-state power amplifiers, to bolster the competitiveness of the European telecommunications industry – the single largest and most commercial space sector.

    ESA Biomass mission depiction

    “These same power transistors shall in the near future be offered on the open market after completion of a project funded by ESA’s European Component Initiative, which is the first time we’ve achieved that,” adds Andrew. “Such power transistors are also being investigated for use in the next-decade Galileo Second Generation.

    “At the same time we’re in the process of qualifying some of the foundry processes used on a more systematic basis, following European Cooperation for Space Standardization rules. We’re also seeking to develop additional standards in terms of screening and testing and insertion into space systems – this is essential for wider industrial take-up of the technology, and we’re making steady progress.”

    5
    GaN Single Chip Front End. Natanael Ayllon, ESA payload engineer, showing a prototype transmit/receive module on a single gallium nitride chip.

    GREAT2’s focus has now moved to high voltage power converters and amplifiers for higher frequencies, operating at millimetre wavelength. The Ninth Wide Bandgap Workshop hosted at ESA’s Harwell centre in the UK took stock of the general progress made and looked ahead to the next steps towards the wide bandgap future.

    “This includes improving production quality of GaN ‘epitaxy’ – meaning crystal growth – and moving to higher frequency foundry processes for space ready parts, utilizing 100 nanometre gate lengths or lower for GaN,” explains Andrew. Work is also ongoing to test the space radiation robustness of GaN power transistors for DC-DC convertor applications.

    Diamond Light Source, located at the Harwell Science and Innovation Campus in Oxfordshire U.K.

    ESA ECSAT-The European Centre for Space Applications and Telecommunications (ECSAT) is ESA’s facility in the United Kingdom. It is based at the Harwell Campus in Oxfordshire

    “We’ve also worked to boost their general robustness. We found, for instance, that some of the passive components used on GaN monolithic microwave integrated circuit parts weren’t performing so well in radiation testing as expected, and this came down to the legacy of their design, originally these capacitor designs were based on legacy parts built in gallium arsenide. By tuning design parameters, i.e. adjusting the dielectric layer stack, we have now achieved a big improvement.”

    Other wide bandgap materials such as diamond are also under investigation, in their own right and also as a ‘substrate’ backing material for GaN devices to give improved thermal performance.

    6
    Laser alignment for heavy ion radiation testing of GaN power devices at IMEC by ON Semiconductor. ESA

    Andrew comments: “Diamond has a similar crystalline structure to GaN, and excellent thermal conductivity properties. The University of Bristol presented work done in integrating GaN with diamond. The result is a fivefold increase in heat dissipation, allowing even higher power densities – diamond is a GaN’s best friend.”

    The workshop also peered further into the future, with discussions looking forward to GaN-based optoelectronic devices, diamond-based integrated circuits and electric thrusters and the 3D printing of wide bandgap materials, as a means of revolutionising device manufacturing.

    7
    25mm diameter diamond substrates growing in 100mm chemical vapor deposition reactor. University of Bristol

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

    ESA50 Logo large

     
  • richardmitnick 2:20 pm on February 13, 2019 Permalink | Reply
    Tags: Adults With Autism to Benefit From New Employment Center at Rutgers, Applied Research & Technology, , , Rutgers Center for Adult Autism Services, , The first program of its kind in the country   

    From Rutgers University: “Adults With Autism to Benefit From New Employment Center at Rutgers” 

    Rutgers smaller
    Our Great Seal.

    From Rutgers University

    February 14, 2019
    Megan Schumann
    MEGAN.SCHUMANN@rutgers.edu

    2
    Craig Lillard of Princeton (left) who works at Harvest in the Institute for Food Nutrition and Health as part of the Rutgers Center for Adult Autism Services with mentor Doug Stracquadanio. Courtesy of Rutgers University

    Rutgers Center for Adult Autism Services, the first program of its kind in the country, will more than double in size

    The Rutgers University Board of Governors today approved a proposal by the Graduate School of Applied and Professional Psychology to build a new facility for the Rutgers Center for Adult Autism Services (RCAAS) on Rutgers-New Brunswick’s Douglass campus.

    The two-year-old center, the first of its kind at a higher education institution in the United States, currently provides employment, vocational training and other services to 12 participants who commute from home. The expansion will enable the program to serve up to 30 participants. The project, estimated to cost $9.5 million, will be paid for through philanthropic funds.

    Christopher Manente, executive director of RCAAS, said, “We are committed to serving adults with autism by providing meaningful paid employment, full integration into the Rutgers community and ongoing research and training related to helping adults with autism lead full lives. We serve as a model that can be replicated at colleges and universities, or within small communities across the country.”

    Current participants have paying jobs on campus, five days a week, in food service, horticulture maintenance, university mail services, document and records management, the Rutgers Cinema, computer retail services, and other areas. Participants also benefit from individualized services to help them succeed on the job and maintain their independence in the community.

    The new facility will include a multifunctional gathering space and vocational training space, administrative offices for faculty and clinical staff and support spaces and provide community-based job training, life skills and recreational opportunities.

    Autism and autism spectrum disorder are among the fastest-growing developmental disabilities in the United States. Rutgers-New Brunswick’s Graduate School of Applied and Professional Psychology created the center to address the well-documented shortage of quality services that help adults with autism lead meaningful and productive lives, and to conduct research that can inform the development of other programs for adults with autism.

    The new building will be at the location of the former Corwin Dormitories on Nichol Avenue between Comstock Street and Dudley Road in New Brunswick. Its development will include demolition of the vacant Corwin residential buildings. Groundbreaking is expected later this year.

    Rutgers-New Brunswick is a leader in autism research facilities. The Rutgers University Cell and DNA Repository, containing the world’s largest collection of autism biomaterials, and the Douglass Developmental Disabilities Center, which includes an on-campus K-12 day school for children with autism from across New Jersey, are among many research and educational programs for autism at the university.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    rutgers-campus

    Rutgers, The State University of New Jersey, is a leading national research university and the state’s preeminent, comprehensive public institution of higher education. Rutgers is dedicated to teaching that meets the highest standards of excellence; to conducting research that breaks new ground; and to providing services, solutions, and clinical care that help individuals and the local, national, and global communities where they live.

    Founded in 1766, Rutgers teaches across the full educational spectrum: preschool to precollege; undergraduate to graduate; postdoctoral fellowships to residencies; and continuing education for professional and personal advancement.

    As a ’67 graduate of University college, second in my class, I am proud to be a member of

    Alpha Sigma Lamda, National Honor Society of non-tradional students.

     
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