Month: August 2018

New Findings May Lead to Sea Change in Desalination Technology

Colin Poitras – UConn Communications, UConn Today

desalination plant
Desalination plant. (Getty Images)

More than 300 million people around the world rely on desalinated water for part or all of their daily needs — a demand that will only grow with larger populations and improved standards of living.

Accessing the oceans for drinking water, however, requires desalination technologies that are complicated and expensive.

In the current issue of Science, researchers at the University of Connecticut offer a new approach to manufacturing a key facet of the process — the membranes integral to desalination. Using an additive manufacturing approach that employs electrospraying, UConn scientists were able to create ultra-thin, ultra-smooth polyamide membranes that are less prone to fouling and may require less power to move water through them.

The most commonly used technology for desalination is reverse osmosis, a process in which seawater is forced through a membrane capable of removing salts and many other molecule contaminants.  Conventional approaches to making reverse osmosis membranes have not changed in nearly 40 years.

“Today’s membranes for reverse osmosis are not made in a way that allows their properties to be controlled,” says Jeffrey McCutcheon, study author and UConn School of Engineering’s Al Geib Professor of Environmental Engineering Research and Education. “Our approach uses an ‘additive’ technique that allows for control of a membrane’s fundamental properties such as thickness and roughness, which is currently impossible using conventional methods.”

While the use of reverse osmosis continues to rise around the world, many of its drawbacks, which include high energy consumption and a propensity for membranes to foul, continue to plague the industry.

reverse osmosis
Illustration depicting the process of reverse osmosis. (iStock/Getty Images Plus)

The traditional approach to making these membranes is known as interfacial polymerization. This method relies on a self-terminating reaction between an aqueous phase amine and an organic phase acid chloride monomer.  The resulting polyamide films — exceedingly thin, highly selective, and permeable to water — became the gold standard membrane for reverse osmosis.

However, as the field has advanced, the need to better control this reaction to allow for membranes of varying thickness and roughness to optimize water flow and reduce fouling has become more pressing.

UConn’s method provides a superior level of control over the thickness and roughness of the polyamide membrane, says McCutcheon.

Typical polyamide membranes have a thickness between 100 and 200 nanometers (nm) that cannot be controlled. UConn’s electrospray method allows for the controlled creation of membranes as thin as 15 nm and the capacity to control membrane thickness in 4 nm increments, a level of specificity not seen before in this area.  Likewise, typical RO membranes have a roughness of over 80 nm.  UConn researchers were able to create membranes with roughness as low as 2 nm.

“Our printing approach to making polyamide membranes has the additional benefit of being scalable,” McCutcheon says. “Much like electrospinning has seen dramatic improvements in roll-to-roll processing, electrospraying can be scaled with relative ease.”

The authors also say this type of manufacturing could save on chemical consumption as traditional chemical baths are not needed as part of the membrane fabrication process.

“In the lab, we use 95 percent less chemical volume making membranes by printing when compared to conventional interfacial polymerization,” says McCutcheon. “These benefits would be magnified in large-scale membrane manufacturing and make the process more ‘green’ than it has been for the past 40 years.”

This innovative new approach is not limited to desalination and could lead to better membranes for other separation processes, says McCutcheon, who also serves as the executive director of the Fraunhofer USA Center for Energy Innovation at UConn, which develops new applied membrane technologies. “In fact, we hope that this method will enable new materials to be considered for a myriad of membrane separation processes, perhaps in processes where those materials were not, or could not, be used before.”

In addition to McCutcheon, the study authors included Maqsud Chowdhury, a recent Ph.D. graduate in chemical engineering, and the paper’s lead author; James Steffes, a current Ph.D. student, and Bryan Huey, professor of materials science and engineering.

The team has filed a patent application for the technology and is currently working with UConn’s Technology Commercialization Services to explore commercialization options. The team also received an award from the UConn SPARK Technology Commercialization Fund.

The research was supported by a grant from the U.S. Environmental Protection Agency #RD834872, The General Electric Graduate Fellowship for Innovation, the National Science Foundation DMR:MRI Award # 1726862, and the University of Connecticut Academic Plan funding program, and the Department of Chemical and Biomolecular Engineering and Center for Environmental Sciences and Engineering.

‘Smart’ Machine Components Alert Users to Damage and Wear

Colin Poitras – UConn Communications

UTRC 3-D printing
UConn and UTRC scientists are using advanced additive manufacturing to create novel wear sensors that can be embedded into machine parts. (Peter Morenus/UConn Photo)

Scientists at the United Technologies Research Center and UConn are using advanced additive manufacturing technology to create ‘smart’ machine components that alert users when they are damaged or worn.

The researchers also applied a variation of the technology to create polymer-bonded magnets with intricate geometries and arbitrary shapes, opening up new possibilities for manufacturing and product design.

The key to both innovations is the use of an advanced form of 3D printing called direct write technology. Unlike conventional additive manufacturing, which uses lasers to fuse layers of fine metal powder into a solid object, direct write technology uses semisolid metal ‘ink’ that is extruded from a nozzle. The viscosity of the metal ink looks like toothpaste being squeezed from a tube.

This process allowed the UConn-UTRC scientists to create fine lines of conductive silver filament that can be embedded into 3D printed machine components while they are being made. The lines, which are capable of conducting electric current, act as wear sensors that can detect damage to the part.

Here’s how they work. Parallel lines of silver filament, each coupled with a tiny 3D-printed resistor, are embedded into a component. The interconnected lines form an electrical circuit when voltage is applied. As lines are embedded deeper and deeper into a component from the surface, each new line and resistor are assigned an increasingly higher voltage value. Any damage to the component, such as wear or abrasion caused by friction from moving parts, would cut into one or more of the lines, breaking the circuit at that stage. The more lines that are broken, the greater the damage. Real time voltage readings allow engineers to assess potential damage and wear to a component without having to take an entire machine apart.

To get a better idea of how these micro sensors might be used, imagine them being embedded in the ceramic coating of a jet engine turbine fan blade. These blades are subjected to tremendous physical forces and heat. A microscopic crack in the protective coating could potentially be catastrophic to the blade’s performance, yet invisible to the naked eye. With the embedded sensors, mechanics would be alerted to any blade damage promptly so it can be addressed.

UTRC 3-D printing
Sameh Dardona, center, principal research engineer and associate director, United Technologies Research Center, with Anson Ma, associate professor of chemical and biomolecular engineering, right, and Alan Shen, a Ph.D. student, look at a prototype wear sensor at the UTC Research Center in East Hartford on June 18, 2018. (Peter Morenus/UConn Photo)

“This changes the way we look at manufacturing,” says Sameh Dardona, associate director of research and innovation at UTRC, which serves as the innovation engine for United Technologies Corp. “We can now integrate functions into components to make them more intelligent. These sensors can detect any kind of wear, even corrosion, and report that information to the end user. This helps us improve performance, avoid failures, and save costs.”

The UConn-UTRC team was able to embed sensor lines that were just 15 microns wide and 50 microns apart. That’s much thinner than an average human hair, which is about 100 microns. This allows detection of very minute damage. Developing such a precise sensor isn’t easy. UConn associate professor of chemical and biomolecular engineering Anson Ma and a Ph.D. student from Ma’s Complex Fluids Laboratory, Alan Shen, measured and optimized the flow properties of the silver-infused ink so that micron-sized lines could be reliably deposited without clogging the nozzle or causing substantial spreading after deposition.

UTRC’s Dardona has applied for a patent for the embedded wear sensor technology.

UTRC 3-D printing
A 3D-printed magnet created using direct write technology at the UTC Research Center. (Peter Morenus/UConn Photo)

The scientists also used direct write technology to create novel components that have magnetic coatings or magnetic material embedded inside them. These polymer-bonded magnets are capable of conforming to any variety of shape, and eliminate the need for separate housings in machines requiring magnetic parts.

“This opens up a lot of exciting opportunities,” says Ma. “Imagine magnets that can take on different shapes and fit seamlessly between other functional components. Also, the resultant magnetic field that is created may be further manipulated and optimized by changing the shape of the magnets.”

The magnet fabrication method developed by UConn and UTRC significantly improves upon existing manufacturing practices in other ways too. Current methods for creating custom 3D-printed magnets rely on high-temperature curing, which unfortunately reduces a material’s magnetic properties as a result. The scientists at UConn and UTRC found a way around that problem by using low-temperature UV light to cure the magnets, similar to how a dentist uses UV light to harden a filling. The resultant magnets exhibited significantly better performance than magnets created by other additive manufacturing methods.

Magnets have a wide range of industrial applications, from creating electric currents in alternators to tracking the position or speed of moving parts as high-grade sensors. Embedding magnetic material directly into components could lead to new product designs that are more aerodynamic, lighter, and efficient, Dardona says.

“These kinds of collaborations allow us to help companies like UTC develop new technologies that we know they are going to take to the next level,” says Ma. “It’s also very rewarding for our students. Students involved in these projects are fully integrated into the research team. It’s not only great from a workforce development perspective; it also gives students a chance to work closely with professional engineers in a beautiful facility like UTRC.”

More detailed information about fabrication of the wear sensors can be found in an article in Additive Manufacturing. Details about the direct write production of polymer-bonded magnets can be found in an article in the Journal of Magnetism and Magnetic Materials. Two UTRC engineers, Dustin Caldwell and Callum Bailey, also contributed to the research.

The research was made possible with financial support from United Technologies Research Center and Connecticut Space Grant Consortium.

3D Printing: How Does It Work?

By: Vanessa Wojtusiak

3d printing

(WTNH) — 3D printing has become a controversial topic after lawmakers have uncovered a new reality: the ability to print guns using these printers at home. Guns created through this process have been called “ghost guns” and the plastic or metal guns are untraceable.

Professor Ranier Hebert, who is the Head of the University of Connecticut’s Additive Manufacturing Innovation Center, spoke with News 8 about the process of creating 3D print-outs of objects. The fields that the technology is most used in is for manufacturing as well as medical, however, the design industry has also used printing for jewelry.

UConn’s new Innovation Partnership Building has partnered with Connecticut technology companies including EversourceUTCPratt & Whitney and more to innovate and collaborate in the community and learn about new technologies.

This state-of-the-art building stores a variety of equipment, including 3D printers, which have been primarily used for manufacturing. Two types of printers are used to learn and create; plastic printers as well as metal printers. These particular printers range in price – plastic one located at UConn is a few thousand dollars while the more sophisticated metal printers can run upwards of millions of dollars. Consumers, however, can purchase basic plastic printers for about the same cost as a traditional paper printer.

Related Content: Push to Permanently Ban 3D Printed Guns After Federal Judge Blocks Release

Professor Hebert informed us that all someone would need is an object blueprint, which is a digital file plugged in through a USB device into the printer. Materials are then needed in the form or liquid or powder to melt down and create layers which are stacked to create the three-dimensional object. Some items can take only several hours to print, while larger pieces can take days.

Watch News 8’s Facebook Live conversation and see a demo showcasing the difference between a plastic printer and a metal printer at the UConn Innovation Partnership Building.