Researchers Look to Blizzards for Clues on Improving Efficiency of Wind Turbines
A first-of-its-kind study by researchers at the University of Minnesota (UMN) using snow during a Minnesota blizzard is giving researchers new insight into the airflow around large wind turbines. This research is essential to improving wind energy efficiency, especially in wind farms where airflows from many large wind turbines interact with each other.
The study by researchers at the UMN College of Science and Engineering’s St. Anthony Falls Lab was published yesterday in Nature Communications, a major scientific journal.
Wind energy is one of the fastest-growing renewable energy sources. The U.S. Department of Energy estimates energy losses in wind farms to be as high as 10-20 percent and identifies complex airflows created by the turbines as the major culprit for such losses. As wind turbines have grown to more than 100 meters tall, field research in real-world settings has become more difficult.
“In the lab we use tracer particles to measure airflows of wind turbine models in wind tunnels, but our research was extremely constrained by an inability to measure flows at the large scale,” said Jiarong Hong, a UMN mechanical engineering assistant professor and lead researcher on the study. “Most researchers thought measurements of this kind at the real-world scale were impossible.”
Hong, who grew up in southwest China, had only seen snow a few times growing up. When he moved to Minnesota in 2012, he wondered if snow might be the solution to their dilemma.
“We have everything we needed in Minnesota for this research,” Hong said. “We have a fully-equipped large research wind turbine at the U.S. Department of Energy-funded Eolos Wind Energy Research Center run by the University. We also have snow to serve as the particulates to measure the airflows and committed researchers and engineers to carry out such an unprecedented effort.”
After a number of previous attempts when the snow was poor quality or the instruments malfunctioned in the cold weather, researchers headed to the Eolos 2.5 KW wind turbine in Rosemount, MN, in the early morning hours of a snowstorm on Feb. 22, 2013.
They braved the harsh conditions in the middle of the night to set up a large searchlight with specially designed reflecting optics to generate a gigantic light sheet next to the 130-meter-tall wind turbine for illuminating the snow particles in a 36-meter-wide-by-36-meter-high area. The snow is easier to see in the light at night, much like the average person looks into a streetlight to see how much it is snowing during a snowstorm. Researchers videotaped the snow particles as the wind turbine spun to show airflow patterns. The video (below) was digitized and synchronized with wake flow and load data from the fully instrumented research wind turbine.
Results of the experiment showed that this technique was successful in measuring the turbulence of the airflow structure around the wind turbine. It is a first step in showing significant differences in the patterns of airflows in the field at large scale compared to those measured in the lab.
“These measurements are extremely important in our efforts to improve the efficiency of wind energy that will reduce our reliance on fossil fuels,” said Fotis Sotiropoulos, co-author of the study and director of the University’s St. Anthony Falls Lab and the Eolos Wind Energy Research Center. “Who would have ever thought we’d use a Minnesota blizzard to help fight global warming.”
In addition to Hong and Sotiropoulos, other University of Minnesota researchers who were part of this study include civil engineering assistant professor Michele Guala, mechanical engineering Ph.D. student Mostafa Toloui, civil engineering Ph.D. student Kevin Howard, mechanical engineering student Sean Riley, St. Anthony Falls Lab engineer James Tucker, and former post-doctoral researcher Leonardo Chamorro who is now at the University of Illinois at Urbana-Champaign.
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By Kristen Fischer
It's going to be back-to-school time soon, but will children go into the classrooms?
The American Academy of Pediatrics (AAP) thinks so, but only as long as safety measures are in place.
Keeping Schools Safe<p>What will safer schools look like?</p><p>In a <a href="https://jamanetwork.com/journals/jama/fullarticle/2766822" target="_blank">JAMA article</a> published last month, <a href="https://www.jhsph.edu/faculty/directory/profile/1781/joshua-m-sharfstein" target="_blank">Dr. Joshua Sharfstein</a>, a pediatrician and professor at the Johns Hopkins Bloomberg School of Public Health, outlined suggestions — many of which are similar to AAP's.</p><p>Remote learning protocols must stay in place, especially as some schools stagger home and in-building learning. If another shutdown needs to occur, children will rely on distance learning completely, so it must be easy to switch to, he said.</p><p>He suggested giving parents a daily checklist to document their child's health. Kids should be screened quickly on arrival and be given hygiene supplies. Maintenance staff should use appropriate PPE and have regular cleaning schedules. A notification system should be in place if a case is identified, Sharfstein recommended.</p><p><a href="https://www.albany.edu/rockefeller/faculty/erika-martin" target="_blank">Erika Martin</a>, PhD, an associate professor of public administration and policy at University at Albany, said nutrition assistance and health services should be included. She called for tutoring programs with virtual options as well as technology access.</p>
Supporting Staff<p>Teachers and staff will be affected by safeguarding measures, noted <a href="https://directory.sph.umn.edu/bio/sph-a-z/rachel-widome" target="_blank">Rachel Widome</a>, PhD, an associate professor of epidemiology and community health at University of Minnesota.</p><p>"In order for all of the in-school precautions to work well, we'll be asking a lot of teachers and staff," Widome told Healthline. In addition to their usual workload, they'll now be asked to monitor mask-wearing, ensure children are keeping distance, and be aware of any symptoms.</p><p>Along with Sharfstein, Widome called for an increase in financial support. More employees will likely be required so teachers and staff members can keep up with the added demands.</p>
Should Kids Go Back?<p>While these guidelines may help get some schools to reopen, many people don't think children should go back to school over fears they could contract the disease and spread it to other vulnerable family members like grandparents, infant siblings, or their parents.</p><p>In a <a href="https://pediatrics.aappublications.org/content/early/2020/07/08/peds.2020-004879" target="_blank">Pediatrics</a> commentary, <a href="https://www.md.com/doctor/william-raszka-md" target="_blank">Dr. William V. Raszka, Jr.</a>, an infectious disease specialist at The University of Vermont Medical Center, argued that schools should open because school-aged children are far less important drivers of COVID-19 than adults.</p><p>But he says the risk and benefit is not equal among all students ages 5 to 18.</p><p>"Elementary schools are arguably higher priority for face-to-face schooling, since younger children are at lower risk for infection and transmission, and since parental supervision of younger children's distance learning may be particularly challenging," added Sorensen, who penned a <a href="https://jamanetwork.com/channels/health-forum/fullarticle/2767411" target="_blank">June article in JAMA</a> with reopening tips. "That means middle and high schools are more likely to emphasize distance learning."</p><p>Specific student populations, such as special education students and students with disabilities, would also benefit greatly from more time spent in face-to-face environments, Sorensen said.</p>
What Parents Can Do<p>Parents should ask for and receive frequent updates from schools about plans for the fall. They should also be informed about plans if and when COVID infections are identified, Sharfstein said.</p><p>"I'd like to see parents investing now, during the summer, in doing things that can slow and stop the spread of the virus in their communities," Widome said.</p><p>"Now is a good time for kids to practice wearing masks and get used to them as they may be wearing them for longer stretches if school starts up in person," Widome suggested.</p><p>She recommends parents try different mask designs and materials to see what children are more comfortable wearing.</p><p>"If you are using cloth face coverings, it's good to have extras on hand," Widome added.</p><p>Parents should model healthy behavior at home and while out in public — another thing that could affect how well children adapt to reopening practices, Sorensen said.</p><p>"Children may want to know more about face coverings," added <a href="https://www.linkedin.com/in/leescott/" target="_blank">Lee Scott</a>, chairwoman of the Educational Advisory Board at <a href="https://www.goddardschool.com/" target="_blank">The Goddard School</a>. "Dramatic play, such as creating or wearing a face covering, may help some children adjust to this concept." Schools can also show children photos of what faculty members look like in their masks so the students are familiar with that appearance.</p><p>Johns Hopkins University recently released its eSchool+ Initiative, a slew of resources surrounding education during the pandemic. These include a <a href="https://equityschoolplus.jhu.edu/reopening-checklist/" target="_blank">checklist for administrators</a>, report on <a href="https://equityschoolplus.jhu.edu/ethics-of-reopening/" target="_blank">ethical considerations</a>, and a tracker of <a href="https://equityschoolplus.jhu.edu/reopening-policy-tracker/" target="_blank">state and local reopening plans</a>.</p>
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By Eoin Higgins
Over 300 groups on Monday urged Senate leadership to reject a bill currently under consideration that would incentivize communities to sell off their public water supplies to private companies for pennies on the dollar.
<div id="fea63" class="rm-shortcode" data-rm-shortcode-id="9a6f211c2bc5aedd34837944cb8eeedf"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1281000111481294849" data-partner="rebelmouse"><div style="margin:1em 0">Water in Illinois is overwhelmingly public. Why is Tammy Duckworth sponsoring a bill that aims to change that? https://t.co/1V36Kkd99s</div> — The American Prospect (@The American Prospect)<a href="https://twitter.com/TheProspect/statuses/1281000111481294849">1594249201.0</a></blockquote></div>
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By Alyssa Murdoch, Chrystal Mantyka-Pringle and Sapna Sharma
Summer has finally arrived in the northern reaches of Canada and Alaska, liberating hundreds of thousands of northern stream fish from their wintering habitats.
A Good News Story?<p>On the surface, the <a href="https://doi.org/10.1111/fwb.13569" target="_blank">results from our study</a> appear to provide a "good news" story. Warming temperatures were linked to higher numbers of fish, more species overall and, therefore, potentially more fishing opportunities for northerners.</p><p>Initially, we were surprised to learn that warming was increasing the distribution of cold-adapted fish. We reasoned that modest amounts of warming could lead to benefits such as increased food and winter habitat availability without reaching stressful levels for many species.</p>
Photo of Arctic grayling (left) and Dolly Varden trout (right). Alyssa Murdoch / Lilian Tran / Nunavik Research Centre and Tracey Loewen / Fisheries and Oceans Canada<p>Yet, not all fish species fared equally well. Ecologically unique northern species — those that have evolved in colder, more nutrient-poor environments, such as Arctic grayling and Dolly Varden trout — were showing declines with warming.</p>
Fish Strandings and Buried Eggs<p>Recent news headlines run the gamut for Pacific salmon — from their increased escapades <a href="https://nunatsiaq.com/stories/article/more-pacific-salmon-showing-up-in-western-arctic-waters/" target="_blank">into the Arctic</a> to <a href="https://www.juneauempire.com/news/warm-waters-across-alaska-cause-salmon-die-offs/" target="_blank">massive pre-spawning die-offs</a> in central Alaska. Similarly, results from our study revealed different outcomes for fish depending on local climatic conditions, including Pacific salmon.</p><p>We found that warmer spring and fall temperatures may be helping juvenile salmon by providing a longer and more plentiful growing season, and by supporting early egg development in northern regions that were previously too cold for survival.</p><p>In contrast, salmon declined in regions that were experiencing wetter fall conditions, pointing to an increased risk of flooding and sedimentation that could bury or dislodge incubating eggs.</p>
Headwaters of the Wind River within the largely intact Peel River watershed in northern Canada. Don Reid / Wildlife Conservation Society Canada / Author provided<p>Interestingly, we found that certain climatic combinations, such as warmer summer water temperatures with decreased summer rainfall, were important in determining where Pacific salmon could survive. Summer warming in drier watersheds led to declines, suggesting that lowered streamflows may have increased the risk of fish becoming stranded in subpar habitats that were too warm and crowded.</p>
The Fate of Northern Fisheries<p>The promise of a warmer and more accessible Arctic has attracted mounting interest in new economic opportunities, <a href="https://doi.org/10.1016/j.marpol.2019.103637" target="_blank">including fisheries</a>. As warming rates at higher latitudes are already <a href="https://www.ipcc.ch/sr15/" target="_blank">two to three times global levels</a>, it seems probable that northern biodiversity will experience dramatic shifts in the coming decades.</p><p>Despite the many unknowns surrounding the future of Pacific salmon, many fisheries are currently <a href="https://doi.org/10.1080/03632415.2017.1374251" target="_blank">thriving following warmer and more productive northern oceans</a>, and some <a href="https://doi.org/10.14430/arctic68876" target="_blank">Arctic Indigenous communities are developing new salmon fisheries</a>.</p><p>As warming continues, the commercial salmon fishing industry is poised to expand northwards, but its success will largely depend on extenuating factors such as <a href="https://www.eenews.net/stories/1060023067" target="_blank">changes to marine habitat and food sources</a> and <a href="https://www.yukon-news.com/news/promising-chinook-salmon-run-failed-to-materialize-in-the-yukon-river-panel-hears/" target="_blank">how many fish are caught during the freshwater stages of their journey</a>.</p><p>Even with the potential for increased northern biodiversity, it is important to recognize that some northern communities may be unable to adapt or may <a href="https://thenarwhal.ca/searching-for-the-yukon-rivers-missing-chinook/" target="_blank">lose individual species that are associated with important cultural values</a>.</p>
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By Joni Sweet
If you get a call from a number you don't recognize, don't hit decline — it might be a contact tracer calling to let you know that someone you've been near has tested positive for the coronavirus.
Interviews With Contact Tracers<p>Contact tracing is a public health strategy that involves identifying everyone who may have been in contact with a person who has the coronavirus. Contact tracers collect information and provide guidance to help contain the transmission of disease.</p><p>It's been used during outbreaks of sexually transmitted infections (STIs), Ebola, measles, and now the coronavirus that causes COVID-19.</p><p>It starts when the local department of health gets a report of a confirmed case of the coronavirus in its community and gives that person a call. The contact tracer usually provides information on how to isolate and when to get treatment, then tries to figure out who else the person may have exposed.</p><p>"We ask who they've been in contact with in the 48 hours prior to symptom onset, or 2 days before the date of their positive test if they don't have symptoms," said <a href="https://case.edu/medicine/healthintegration/people/heidi-gullett" target="_blank">Dr. Heidi Gullett</a>, associate director of the Center for Community Health Integration at the Case Western Reserve University School of Medicine and medical director of the Cuyahoga County Board of Health in Ohio.</p>
“You’ve Been Exposed”<p>After the case interview, contact tracers will get to work calling the folks who may have been exposed to the coronavirus by the person who tested positive.</p><p>"We give them recommendations about quarantining or isolating, getting tested, and what to do if they become sick. If they're not already sick, we still want them to self-quarantine so that they don't spread the disease to anyone else if they were to become sick," said Labus.</p><p>Generally, the contact tracer won't ask for additional contacts unless they happen to call someone who is sick or has a confirmed case of the virus. They will help ensure the contact has the resources they need to isolate themselves, if necessary. The contact tracer may continue to stay in touch with that person over the next 14 days.</p><p>"We follow the percentage of people that were contacts, then converted into being actual cases of the virus. It's an important marker to help us understand what kind of transmission happens in our community and how to control the virus," said Gullett.</p>
Why You Should Participate (and What Happens If You Don’t)<p>A <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30457-6/fulltext" target="_blank">Lancet study</a> from June 16, which looked at data from more than 40,000 people, found that COVID-19 transmission could be reduced by 64 percent through isolating those who have the coronavirus, quarantining their household, and contacting the people they may have exposed.</p><p>The combination strategy was significantly more effective than mass random testing or just isolating the sick person and members of their household.</p><p>However, contact tracing is only as effective as people's willingness to participate, and a small number of people who've contracted the coronavirus or were potentially exposed are reluctant to talk.</p><p>"Contact tracers have all been hung up on, cussed at, yelled at," said Gullet.</p><p>The hesitation to talk to contact tracers often stems from concerns over privacy — a serious issue in healthcare.</p>
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