From The Whiting School of Engineering
At
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Jill Rosen
jrosen@jhu.edu
Office 443-997-9906
Cell 443-547-8805
From left, Michael Chacon, Madison Morrison, Andrew Palacio, and Leen Alfaoury
Image credit: Will Kirk / Johns Hopkins University
Patent-pending design by Johns Hopkins undergrads could be available in stores within two years.
Hearing is Be-leafing: Students Invent Quieter Leaf Blower
Video credit: Aubrey Morse / Johns Hopkins University
The challenge before Johns Hopkins University engineering students: Take a leaf blower, but make it quiet. Make it work as powerfully as ever, but do not allow it to emit the ear-piercing caterwaul that has gotten leaf blowers banned in some communities and cursed in many others.
Shocking their sponsors, their advisers, and even themselves a little, the students did it.
Their improved leaf blower drops the overall noise level by nearly 40% while almost entirely erasing the most obnoxious frequencies. The design is patent-pending and Stanley Black & Decker expects to be selling them in two years.
“We spent many hours on this project, just going through the various versions of it, just constantly iterating and improving and so for that to finally pay off, this was really, really rewarding,” said team member Michael Chacon, who like the rest of the four-member team is a senior majoring in mechanical engineering. “We are stoked and super, super proud.”
The team started working last September. They hoped to improve an electric or battery-powered leaf blower, which is already much quieter than the notorious gas-powered ones, where the sound can carry over an average suburban block.
They spent months figuring out the leaf blower piece by piece, analyzing all of its the noises and why it made them. They then spent many more months spit-balling possible improvements, refining some ideas, killing even more.
“The sound that comes out of this leaf blower is very complicated and it contains a lot of different frequencies,” said team member Andrew Palacio. “A lot of different notes on a piano would be a good analogy.”
They workshopped more than 40 versions of the solution they finally settled on: an attachment that cuts the machine’s noise almost like a silencer on a gun or a muffler on a car.
“Our product takes in a full blow of air and separates it,” said team member Leen Alfaoury. “Some of that air comes out as it is, and part of it comes out shifted. The combination of these two sections of the air makes the blower less noisy.”
Adds Chacon: “It ultimately dampens the sound as it leaves, but it keeps all that force, which is the beauty of it.”
Their design cuts the most shrill and annoying frequencies by about 12 decibels, which all but removes them, making them 94% quieter. The team reduced the overall leaf blower noise by about two decibels, making the machine sound 37% quieter.
So it’s a quieter machine, and what people can hear will sound more pleasant.
Image credit: Will Kirk / Johns Hopkins University
“It’s the difference between hearing a high-pitched whistle and hearing what you might think of as wind noise,” said team member Madison Morrison.
Alfaoury thinks the best way to describe it is “muffled.”
“It’s suppressed, if that makes sense,” she said. “Like the noise is deeper. It is not screechy. There’s no high pitch sound that is like really annoying to hear.”
Team adviser Stephen Belkoff puts it bluntly: “It’s still a leaf blower but it’s not nearly as annoying as it was before they got involved.”
The design wowed Stanley Black & Decker officials, who can’t wait to start manufacturing and selling the new tools.
“It’s not just some cool theoretical thing that will sit on a shelf and never be heard from again—this is ready to be mass manufactured,” said Nate Greene, senior product manager at Stanley Black & Decker, who graduated from Johns Hopkins in 2017 with an engineering degree. “This is a really rare and dramatic level of success.”
The student team expects their solution could be adapted to quiet other similarly loud appliances like vacuums and hairdryers.
See the full article here .
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The G.W.C. Whiting School of Engineering is a division of The Johns Hopkins University located in the university’s Homewood campus in Baltimore, Maryland.
Engineering at Johns Hopkins was originally created in 1913 as an educational program that included exposure to liberal arts and scientific inquiry. In 1919, the engineering department became a separate school, known as the School of Engineering. By 1937, over 1,000 students had graduated with engineering degrees. By 1946 the school had six departments.
In 1961, the School of Engineering changed its name to the School of Engineering Sciences and, in 1966, merged with the Faculty of Philosophy to become part of the School of Arts and Sciences. In 1979, the engineering programs were organized into a separate academic division that was named the G.W.C. Whiting School of Engineering. The school’s named benefactor is George William Carlyle Whiting, co-founder of The Whiting-Turner Contracting Company.
Several departments at the school have been nationally and historically recognized. The Johns Hopkins Department of Biomedical Engineering is recognized as the top-ranked program in the nation. The Department of Geography and Environmental Engineering has consistently ranked as one of the top 5 programs nationally by U.S. News & World Report in recent years.
The Department of Mechanical Engineering is well known for its fundamental and historic contributions, especially in the fields of mechanics and fluid dynamics. Although it has always been a very small department, an uncharacteristically large number of highly acclaimed scholars have been associated with it over the years. These include Clifford Truesdell, Owen Martin Philips, Jerald Ericksen, James Bell, Stanley Corrsin, Robert Kraichnan, John L. Lumley, Leslie Kovasznay, Walter Noll, K. R. Sreenivasan, Hugh Dryden, Shiyi Chen, Andrea Prosperetti, Fazle Hussain, Harry Swinney, Stephen H. Davis, Gregory L. Eyink, Charles Meneveau, Joseph Katz (professor), Lauren Marie Gardner, Gretar Tryggvason and Mohamed Gad-el-Hak. Many of the landmark papers in the field of fluid mechanics (turbulence in particular) were written using data from the Corrsin Wind Tunnel Laboratory. The wind tunnel is still in operation today. The department was also home to the school of rational mechanics. It was recently ranked as one of the top 5 departments in the nation for research activity by the National Research Council (the department was ranked 13th by the generic U.S. News & World Report rankings), and is still considered one of the main centers of fundamental research in fluid dynamics and solid mechanics.
Johns Hopkins University opened in 1876, with the inauguration of its first president, Daniel Coit Gilman. “What are we aiming at?” Gilman asked in his installation address. “The encouragement of research … and the advancement of individual scholars, who by their excellence will advance the sciences they pursue, and the society where they dwell.”
The mission laid out by Gilman remains the university’s mission today, summed up in a simple but powerful restatement of Gilman’s own words: “Knowledge for the world.”
What Gilman created was a research university, dedicated to advancing both students’ knowledge and the state of human knowledge through research and scholarship. Gilman believed that teaching and research are interdependent, that success in one depends on success in the other. A modern university, he believed, must do both well. The realization of Gilman’s philosophy at Johns Hopkins, and at other institutions that later attracted Johns Hopkins-trained scholars, revolutionized higher education in America, leading to the research university system as it exists today.
The Johns Hopkins University is a private research university in Baltimore, Maryland. Founded in 1876, the university was named for its first benefactor, the American entrepreneur and philanthropist Johns Hopkins. His $7 million bequest (approximately $147.5 million in today’s currency)—of which half financed the establishment of the Johns Hopkins Hospital—was the largest philanthropic gift in the history of the United States up to that time. Daniel Coit Gilman, who was inaugurated as the institution’s first president on February 22, 1876, led the university to revolutionize higher education in the U.S. by integrating teaching and research. Adopting the concept of a graduate school from Germany’s historic Ruprecht Karl University of Heidelberg, [Ruprecht-Karls-Universität Heidelberg] (DE), Johns Hopkins University is considered the first research university in the United States. Over the course of several decades, the university has led all U.S. universities in annual research and development expenditures. The university has graduate campuses in Italy, China, and Washington, D.C., in addition to its main campus in Baltimore.
Johns Hopkins is organized into 10 divisions on campuses in Maryland and Washington, D.C., with international centers in Italy and China. The two undergraduate divisions, the Zanvyl Krieger School of Arts and Sciences and the Whiting School of Engineering, are located on the Homewood campus in Baltimore’s Charles Village neighborhood. The medical school, nursing school, and Bloomberg School of Public Health, and Johns Hopkins Children’s Center are located on the Medical Institutions campus in East Baltimore. The university also consists of the Peabody Institute, Applied Physics Laboratory, Paul H. Nitze School of Advanced International Studies, School of Education, Carey Business School, and various other facilities.
Johns Hopkins was a founding member of the American Association of Universities. Nobel laureates and Fields Medalists have been affiliated with Johns Hopkins. Founded in 1883, the Blue Jays men’s lacrosse team has captured national titles.
Research
The opportunity to participate in important research is one of the distinguishing characteristics of Hopkins’ undergraduate education. About 80 percent of undergraduates perform independent research, often alongside top researchers. Johns Hopkins has members of the Institute of Medicine, The Howard Hughes Medical Institute Investigators, The National Academy of Engineering, and The National Academy of Sciences. Nobel Prize winners have been affiliated with the university as alumni, faculty members or researchers.
The Johns Hopkins University is among the most cited institutions in the world ranking No. 3 globally [after Harvard University and The MPG Society (DE)] in the number of total citations published in Thomson Reuters-indexed journals over 22 fields in America.
Johns Hopkins received research grants from The National Aeronautics and Space Administration, as a leading recipient of NASA research and development funding. Totals include grants and expenditures of JHU’s Applied Physics Laboratory in Laurel, Maryland.
The Johns Hopkins University also offers the “Center for Talented Youth” program—a nonprofit organization dedicated to identifying and developing the talents of the most promising K-12 grade students worldwide. As part of the Johns Hopkins University, the “Center for Talented Youth” or CTY helps fulfill the university’s mission of preparing students to make significant future contributions to the world. The Johns Hopkins Digital Media Center (DMC) is a multimedia lab space as well as an equipment, technology and knowledge resource for students interested in exploring creative uses of emerging media and use of technology.
In 2013, the Bloomberg Distinguished Professorships program was established by a $250 million gift from Michael Bloomberg. This program enables the university to recruit fifty researchers from around the world to joint appointments throughout the nine divisions and research centers. For The American Academy of Arts and Sciences each professor must be a leader in interdisciplinary research and be active in undergraduate education. Directed by Vice Provost for Research, there are Bloomberg Distinguished Professors at the university, including Nobel Laureates, fellows of the American Association for the Advancement of Science, members of the American Academy of Arts and Sciences, and members of the National Academies.