Friday, April 28, 2017

NC State and UNC biomedical engineers develop paper pumps

A hydraulic battery pumping fluid through a simple microchannel

Biomedical engineering researchers from North Carolina State University and the University of North Carolina at Chapel Hill have developed inexpensive paper pumps that use capillary action to power portable microfluidic devices, opening the door to a range of biomedical tools. Microfluidic devices manipulate fluids that have a volume of one microliter or less – substantially smaller than a single teardrop. These devices hold promise for use in applications ranging from biomedical diagnostic tools to drug testing technologies.
“One longstanding challenge to the development of portable, real-world microfluidic device technologies has been the need to find a cost-effective way to pump fluids through the device when outside the lab,” says Glenn Walker, co-corresponding author of a journal article on the work and an associate professor in the joint biomedical engineering program at NC State and UNC. “Portability is important because it makes new applications possible, such as diagnostic tools that can be used in the field. Electric pumps, and tubing to connect them, are fine for a laboratory environment, but those aren’t easy to take with you.”
Now Walker and his collaborators have developed a new way to not only pump fluids through microfluidic devices, but to exert substantial control over that flow. They can stop and re-start the flow, control the rate of the flow, and control how long the flow lasts. “And, because our approach is a new twist on an age-old technology, our pumps are extremely cost effective,” Walker says.
The age-old technology he’s referring to is paper. The researchers call their pumping system a hydraulic battery, but it doesn’t involve electricity in any way. Instead, the battery draws its pumping power from capillary action.
If you’ve ever seen a paper towel soak up a spill, you’ve seen capillary action at work. Broadly speaking, capillary action is the tendency of liquids to be drawn into small spaces by surface tension. In the context of the hydraulic battery, it is the tendency of water – and aqueous liquids, such as blood – to be drawn into the pores found in a piece of paper.
“Our system uses pieces of paper 125 microns thick, little more than the width of a single hair,” Walker says. “Capillary action pulls a liquid into the paper. And by changing the shape of the paper, we are able to control how much liquid is pulled through an attached device – and how quickly that happens.” The shape can be changed in two dimensions by simply cutting out the paper. But it can also be manipulated in three dimensions by stacking multiple pumps on top of each other. “By stacking the paper we are able to create more complex flow profiles, depending on the needs for any given application,” Walker says. “And any one of these hydraulic battery pumps costs less than a dime.”
There are other portable means for pumping liquid through a microfluidic device, but Walker feels that the paper pumps his team has developed hold several significant advantages. “Our hydraulic battery is small, lightweight, very inexpensive, easy to connect to a device and disposable,” Walker says. “In addition, our paper pumps could be saved for later evaluation, such as to run secondary, lab-based tests to confirm on-site diagnoses.”
The researchers have filed a patent application on the paper pump technology and are currently looking for industry partners to help bring it to the marketplace. “We’re optimistic that it could make a difference in both public health and advancing fundamental research,” Walker says.
The paper, “Modular pumps as programmable hydraulic batteries for microfluidic devices,” is published in the journal Technology. Lead author of the paper is Brian Cummins, a former postdoctoral researcher in the joint biomedical engineering program. Co-corresponding author of the paper is Frances Ligler, Lampe Distinguished Professor of Biomedical Engineering at NC State and UNC. The paper was co-authored by Rukesh Chinthapatla and Balaji Lenin, both of whom are undergraduates at NC State. The work was done with support from the NC State University Chancellor’s Innovation Fund.

Saturday, April 22, 2017

POWER Engineers works to bring more reliable power to southern Kansas

Construction of new transmission lines and substations by Wheatland Electric Cooperative will allow the delivery of more reliable power to southern Kansas homes and businesses. POWER Engineers (POWER) is providing Wheatland Electric the engineering design and other services to seamlessly coordinate work on two transmission and four substation projects needed to significantly improve system reliability.

The work at Wheatland Electric is being done in conjunction with major transmission upgrades by Mid-Kansas Electric Company in the same area and includes new 138-kilovolt (kV) lines in the areas of Caldwell and Conway Springs. It also includes construction of new substations at Caldwell, Conway Springs, and Rago. A fourth substation at Bluff City will get upgrades to accommodate the new 138-kV line.

“The new 138-kV lines will provide a much more reliable source than the existing lines and will better support present and future power demands,” says Brian Tomlinson, POWER’s project manager for the work at Wheatland Electric. “The new lines, along with Mid-Kansas transmission additions, will give local distribution substations two paths to deliver electricity, providing Wheatland Electric more flexibility for restoring power during an outage, such as during a storm, thereby improving reliability.” The higher voltage lines also allow industry to consider building in areas that previously could not support their needs for electricity.

Besides engineering design, POWER’s services for the projects include support for procuring materials, putting together construction contracts, issuing construction documents to contractors, evaluating bids, recommending contract awards, holding pre-construction meetings, and more. The majority of the power projects are expected to be completed by the end of 2017.

POWER Engineers is a global consulting engineering firm specializing in the delivery of integrated solutions for energy, food and beverage facilities, communications, environmental, and federal markets. POWER Engineers offers complete multidisciplinary engineering and program management services. Founded in 1976, it is an employee-owned company with more than 2,100 employees and over 45 offices throughout the United States and abroad.

Saturday, April 15, 2017

Missouri S&T researchers develop ways to improve machining processes


Fixing flaws introduced during the machining of large components used in the aircraft and heavy equipment industries can be time-consuming for manufacturers and costly if they must scrap the flawed parts after they’ve been fabricated. A new approach developed by researchers at Missouri University of Science and Technology is helping manufacturers eliminate those flaws before the parts are created.

Writing in the February 2017 issue of the Journal of Manufacturing Science and Engineering (JSME), the Missouri S&T researchers describe an approach that can greatly improve the accuracy of five-axis machine tools used to fabricate large parts. Five-axis machine tools are computer-numerically controlled (CNC) machines that can move, cut, or mill a part on five different axes at the same time. This allows manufacturers to create complex contours or curves when creating a large part such as an aircraft wing.

“Five-axis machine tools are known to have 41 basic geometric errors,” says Jennifer Creamer, a Ph.D. student in mechanical engineering at Missouri S&T and the lead author of the JMSE paper. As Dr. Robert Landers, professor of mechanical and aerospace engineering and a co-author of the paper, puts it, “The way you want the machine to move when making a large part is different than the way it actually moves due to inherent geometric errors.” Because of these errors, manufacturers must make adjustments in calibrating their CNC machines.

Several different approaches exist to help compensate for those errors, but none of them provides a complete picture, Creamer says. Manufacturers must combine various methods to get the best sense of a milling problem. The result, she says, is “a piecemeal approach that makes calibration a time-consuming and expensive process." In her research, Creamer set out to find a way to eliminate that piecemeal approach and develop a new model for capturing complicated geometric errors while also automatically generating compensation tables for those errors. A compensation table is a kind of map of errors that can be programmed into a CNC machine to reduce errors.

Flaws in the fabrication of large parts may seem insignificant given the large size of the parts, but they can cause problems. Parts for airplanes, for example, can be 120 feet long, and their size can make holding tight tolerances problematic, Landers says. In Creamer’s research on five-axis machine tools, “She’s trying to hold errors to five thousandths of an inch over 120 feet,” he says.

In collaboration with colleagues at Boeing Research and Technology in St. Louis, where she works as an engineer, Creamer used a laser tracker to quickly measure the motion of all axes over the entire workspace of an industrial five-axis machine. Based on these measurements, she generated a set of compensating tables that could be used to improve the accuracy on a variety of machine tools and related platforms.

Creamer’s paper, titled “Table-Based Volumetric Error Compensation of Large Five-Axis Machine Tools," was originally published online in September 2016 (https://manufacturingscience.asmedigitalcollection.asme.org/article.aspx?articleID=2543543). Co-authors with Creamer are Landers; Dr. Patrick Sammons, who earned his Ph.D. from Missouri S&T in 2016 and is now a postdoctoral researcher at the University of Michigan; Dr. Douglas Bristow, associate professor of mechanical and aerospace engineering at Missouri S&T; Dr. Philip Freeman, senior technical fellow at Boeing; and Samuel Easley, an engineer at Boeing. The research is supported by Missouri S&T, the Boeing Company, and Missouri S&T’s Center for Aerospace Manufacturing Technologies.

Creamer is also supported through a GAANN Fellowship at Missouri S&T. GAANN (Graduate Assistance in Areas of National Need) is a U.S. Department of Education program designed to encourage more graduate-level education in areas of national need.

Friday, April 7, 2017

Thornton Tomasetti acquires Swallow Acoustic Consultants

Thornton Tomasetti, an international engineering firm, has acquired Swallow Acoustic Consultants Limited (SACL), a specialist in acoustics, noise, and vibration control engineering based in Mississauga, Ontario, Canada. The addition of Swallow bolsters Thornton Tomasetti's Structural Engineering and Forensics practices as well as its Canadian presence.

Founded in the early 1990s by John Swallow, SACL offers a broad range of services in acoustics design and forensics and noise and vibration analysis and control. These include architectural acoustics; environmental, industrial and mechanical noise control; acoustic and vibration testing; expert witness testimony; technical writing and standards; construction vibration assessment; and vibration control.

In addition to its Mississauga headquarters, the 13-person firm has an office in Ottawa, Ontario, Canada. John Swallow will become a principal at Thornton Tomasetti, while Ramin Behboudi and Michael Wesolowsky will join as associate principals.

SACL is one of a small number of firms worldwide that designs tuned mass dampers (TMD), a device used to help stabilize buildings against wind sway and other kinds of motion. Its TMD work includes tall buildings and long-span structures such as sports facilities and bridges. SACL's TMD capabilities will dovetail with Thornton Tomasetti's efforts in the field, which includes the development of a fluid harmonic disruptor based on NASA technology.

Starting with Manhattan's LaGuardia School for the Arts in 1988, Thornton Tomasetti has collaborated on many projects with SACL as well as strategic partner Tacet Engineering, whose staff SACL acquired in 2012. These include Chifley Tower in Sydney, Australia; Soldier Field in Chicago, Illinois; Qatar National Convention Centre in Doha; and most recently, T-Mobile Arena in Las Vegas, Nevada, which opened last April. SACL has worked in some 20 countries and has a considerable presence in central and eastern Canada. This will give Thornton Tomasetti a larger footprint in Canada, having opened its first office in the country in Toronto earlier this year.

According to Thomas Scarangello, chairman and CEO of Thornton Tomasetti, "For nearly 30 years, Swallow has been our go-to partner for vibration issues. Through our close collaboration on many diverse projects, we have built a strong working relationship." John Swallow, president and founder of Swallow Acoustic Consultants, adds, "Teaming with Thornton Tomasetti will allow us to serve current and future clients in new and innovative ways. We look forward to sharing our considerable experience in the acoustics, noise, and vibration control fields with Thornton Tomasetti's professionals."

Thornton Tomasetti is involved in engineering design, investigation, and analysis, serving clients worldwide on projects of all sizes and complexity. Through its 10 complementary practices, Thornton Tomasetti addresses the full life cycle of a structure. They have supported clients working in more than 50 countries, with projects that include the tallest buildings and longest spans to the restoration of prized historic properties. Thornton Tomasetti consists of more than 1,200 engineering, architecture, sustainability, and support professionals that collaborate from offices across North America, Asia-Pacific, Europe, Latin America, and the Middle East.