Founded when Wisconsin achieved statehood in 1848, UW–Madison is the official state university of Wisconsin, and the flagship campus of the University of Wisconsin System. It was the first public university established in Wisconsin and remains the oldest and largest public university in the state. It became a land-grant institution in 1866. The 933-acre (378 ha) main campus includes four National Historic Landmarks. Madison has been labeled one of the “Public Ivies,” a publicly funded university considered as providing a quality of education comparable to those of the Ivy League.
UW–Madison is organized into 20 schools which enrolled 29,153 undergraduate, 8,710 graduate, and 2,570 professional students and granted 6,040 bachelor’s, 3,328 graduate and professional degrees in 2008. The University employs over 16,000 faculty, staff, and graduate students. Its comprehensive academic program offers 135 undergraduate majors, along with 151 master’s degree programs and 107 doctoral programs.
The UW is categorized as an RU/VH Research University (very high research activity) in the Carnegie Classification of Institutions of Higher Education. In 2010, it had research expenditures of more than 1 billion dollars. In 2008, the University’s R&D expenditures were ranked the third highest in the nation. Wisconsin is a founding member of the Association of American Universities.
University of Wisconsin-Madison research articles from Innovation Toronto
- Benign bacteria block mosquitoes from transmitting Zika, chikungunya viruses – July 2, 2016
- Finding Zika one paper disc at a time in 2 to 3 hours – May 7, 2016
- Experimental Drug Cancels Effect From Key Intellectual Disability Gene in Mice – April 28, 2016
- With simple process, engineers fabricate fastest flexible silicon transistor for flexible electronics – April 21, 2016
- Fish-eyed lens cuts through the dark – April 18, 2016
- World’s thinnest lens to revolutionise cameras – March 12, 2016
- Power walk: Footsteps could charge mobile electronics – February 14, 2016
- Nanosheet growth technique could revolutionize nanomaterial production – February 1, 2016
- A compassionate approach leads to more help and less punishment – December 20, 2015
- Wisconsin Scientists Grow Functional Vocal Cord Tissue in the Lab – November 28, 2015
- UW–Madison engineers reveal record-setting flexible phototransistor – November 1, 2015
- Discovery of a highly efficient catalyst eases way to hydrogen economy – September 15, 2015
- Machine teaching holds the power to illuminate human learning – August 17, 2015
- Nanoscale light-emitting device can emit light as powerfully as an object 10,000 times its size – July 16, 2015
- New nanogenerator harvests power from rolling tires – June 30, 2015
- UW-Madison startup offers antibiotic alternative to animal producers – June 2, 2015
- A new kind of wood chip: collaboration could lead to biodegradable computer chips – May 31, 2015
- Simple sample: Federal grant advances pain-free blood tests from UW startup – April 24, 2015
- Plowing prairies for grains: Biofuel crops replace grasslands nationwide – April 4, 2015
- Infamous study of humanity’s ‘dark side’ may actually show how to keep it at bay – January 12, 2014
- Scientists Get to the Heart of Fool’s Gold as a Solar Material – November 20, 2014
- See-through sensors open new window into the brain – October 21, 2014
- Yogic Breathing Shows Promise in Reducing Symptoms of Post-Traumatic Stress Disorder – September 12, 2014
- Best-ever efficiency points to clean, green gas-diesel engine – July 16, 2014
- With graphene a narrow enough ribbon will transform a conductor into a semiconductor – July 6, 2014
- A discovery is made that could revolutionize the computer and telecommunications industry | topological insulators – May 4, 2014
- The key to easy asthma diagnosis is in the blood – April 16, 2014
- At Long Last: A Concrete That’s Nearly Maintenance-Free – April 10, 2014
- Renewable chemical ready for biofuels scale-up | biofuel
- Mouse studies reveal promising vitamin D-based treatment for MS
- Unprecedented genome editing control in flies promises insight into human development, disease
- New gene repair technique promises advances in regenerative medicine
- New catalyst could cut cost of making hydrogen fuel
- Brain Can Be Trained in Compassion, Study Shows
- Stem cell transplant restores memory, learning in mice
- New bird flu strain seen adapting to mammals, humans
- Major symposium on arsenic contamination in food and water supplies
- Low-cost, 3D printable prosthetic hand
- Printed Photonic Crystal Mirrors Shrink On-Chip Lasers Down to Size
- Scientists Produce Eye Structures from Human Blood-Derived Stem Cells
- Despite Safety Worries, Work on Deadly Flu to Be Released
- Metabolic ‘Breathalyzer’ Reveals Early Signs of Disease
- Flu research and public safety
- Flu research and biological warfare
- Microfabrication Breakthrough Could Set Piezoelectric Material Applications in Motion
- Early Warning Signals Of Change: ‘Tipping Points’ Identified Where Sudden Shifts To New Conditions Occur
- Generating hydrogen fuel from waste energy
- Gasoline-diesel ‘Cocktail’: A Potent Recipe For Cleaner, More Efficient Engines
Flooring can be made from any number of sustainable materials, making it, generally, an eco-friendly feature in homes and businesses alike.
Now, however, flooring could be even more “green,” thanks to an inexpensive, simple method developed by University of Wisconsin–Madison materials engineers that allows them to convert footsteps into usable electricity.
Xudong Wang, an associate professor of materials science and engineering at UW–Madison, his graduate student Chunhua Yao, and their collaborators published details of the advance Sept. 24 in the journal Nano Energy.
The method puts to good use a common waste material: wood pulp. The pulp, which is already a common component of flooring, is partly made of cellulose nanofibers. They’re tiny fibers that, when chemically treated, produce an electrical charge when they come into contact with untreated nanofibers.
When the nanofibers are embedded within flooring, they’re able to produce electricity that can be harnessed to power lights or charge batteries. And because wood pulp is a cheap, abundant and renewable waste product of several industries, flooring that incorporates the new technology could be as affordable as conventional materials.
While there are existing similar materials for harnessing footstep energy, they’re costly, nonrecyclable, and impractical at a large scale.
Wang’s research centers around using vibration to generate electricity. For years, he has been testing different materials in an effort to maximize the merits of a technology called a triboelectric nanogenerator (TENG). Triboelectricity is the same phenomenon that produces static electricity on clothing. Chemically treated cellulose nanofibers are a simple, low-cost and effective alternative for harnessing this broadly existing mechanical energy source, Wang says.
Because wood pulp is cheap, abundant and renewable, flooring that incorporates the new technology could be as affordable as conventional materials.
The UW–Madison team’s advance is the latest in a green energy research field called “roadside energy harvesting” that could, in some settings, rival solar power — and it doesn’t depend on fair weather. Researchers like Wang who study roadside energy harvesting methods see the ground as holding great renewable energy potential well beyond its limited fossil fuel reserves.
“Roadside energy harvesting requires thinking about the places where there is abundant energy we could be harvesting,” Wang says. “We’ve been working a lot on harvesting energy from human activities. One way is to build something to put on people, and another way is to build something that has constant access to people. The ground is the most-used place.”
Heavy traffic floors in hallways and places like stadiums and malls that incorporate the technology could produce significant amounts of energy, Wang says. Each functional portion inside such flooring has two differently charged materials — including the cellulose nanofibers, and would be a millimeter or less thick. The floor could include several layers of the functional unit for higher energy output.
“So once we put these two materials together, electrons move from one to another based on their different electron affinity,” Wang says.
The electron transfer creates a charge imbalance that naturally wants to right itself but as the electrons return, they pass through an external circuit. The energy that process creates is the end result of TENGs.
Roadside energy harvesting could, in some settings, rival solar power — and it doesn’t depend on fair weather.
Wang says the TENG technology could be easily incorporated into all kinds of flooring once it’s ready for the market. Wang is now optimizing the technology, and he hopes to build an educational prototype in a high-profile spot on the UW–Madison campus where he can demonstrate the concept. He already knows it would be cheap and durable.
“Our initial test in our lab shows that it works for millions of cycles without any problem,” Wang says. “We haven’t converted those numbers into year of life for a floor yet, but I think with appropriate design it can definitely outlast the floor itself.”
As solar cells produce a greater proportion of total electric power, a fundamental limitation remains: the dark of night when solar cells go to sleep. Lithium-ion batteries, the commonplace batteries used in everything from hybrid vehicles to laptop computers, are too expensive a solution to use on something as massive as the electric grid.
Song Jin, a professor of chemistry at the University of Wisconsin–Madison, has a better idea: integrating the solar cell with a large-capacity battery. He and his colleagues have made a single device that eliminates the usual intermediate step of making electricity and, instead, transfers the energy directly to the battery’s electrolyte.
Jin chose a “redox flow battery,” or RFB, which stores energy in a tank of liquid electrolyte.
In a report now online in Angewandte Chemie International Edition, Jin, graduate student Wenjie Li, and colleagues at the King Abdullah University of Science and Technology in Saudi Arabia have demonstrated a single device that converts light energy into chemical energy by directly charging the liquid electrolyte.
Discharging the battery to power the electric grid at night could hardly be simpler, Jin says. “We just connect a load to a different set of electrodes, pass the charged electrolyte through the device, and the electricity flows out.”
Solar charging and electrical discharging, he notes, can be repeated for many cycles with little efficiency loss.
Unlike lithium-ion batteries, which store energy in solid electrodes, the RFB stores chemical energy in liquid electrolyte. “The RFB is relatively cheap and you can build a device with as much storage as you need, which is why it is the most promising approach for grid-level electricity storage,” says Jin, who also works on several other aspects of solar energy conversion.
In the new device, standard silicon solar cells are mounted on the reaction chamber and energy converted by the cell immediately charges the water-based electrolyte, which is pumped out to a storage tank.
Redox flow batteries already on the market have been attached to solar cells, “but now we have one device that harvests sunlight to liberate electrical charges and directly changes the oxidation-reduction state of the electrolyte on the surface of the cells,” says Li, the first author of the new study. “We are using a single device to convert solar energy and charge a battery. It’s essentially a solar battery, and we can size the RFB storage tank to store all the energy generated by the solar cells.”
The unified design suggests multiple advantages, Jin says. “The solar cells directly charge the electrolyte, and so we’re doing two things at once, which makes for simplicity, cost reduction and potentially higher efficiency.”
Having proven the concept of an integrated, solar-charged battery, Jin and Li are already working on improvements. One would be to match the solar cell’s voltage to the chemistry of the electrolyte, minimizing losses as energy is converted and stored.
The aqueous electrolyte used in the current study contains organic molecules but no expensive rare metals, which raise costs in many batteries. Jin and Li are also searching for electrolytes with larger voltage differential, which currently limits energy storage capacity.
A system that both creates and stores electricity will be judged by cost, efficiency and energy storage density, Jin says. “It’s not just about the efficiency of converting sunlight into electricity, but also about how much energy you can efficiently store in the device.”
As solar energy use grows, the storage problem becomes more acute. “People say the solar electricity capacity cannot exceed about 20 percent of overall grid capacity, because of supply shortages at night or during cloudy weather,” Jin says. “In some places, further solar installations may have to wait until better storage is available.”
For decades, scientists have tried to harness the unique properties of carbon nanotubes to create high-performance electronics that are faster or consume less power — resulting in longer battery life, faster wireless communication and faster processing speeds for devices like smartphones and laptops.
But a number of challenges have impeded the development of high-performance transistors made of carbon nanotubes, tiny cylinders made of carbon just one atom thick. Consequently, their performance has lagged far behind semiconductors such as silicon and gallium arsenide used in computer chips and personal electronics.
Now, for the first time, University of Wisconsin-Madison materials engineers have created carbon nanotube transistors that outperform state-of-the-art silicon transistors.
Led by Michael Arnold and Padma Gopalan, UW-Madison professors of materials science and engineering, the team’s carbon nanotube transistors achieved current that’s 1.9 times higher than silicon transistors. The researchers reported their advance in a paper published Friday (Sept. 2) in the journal Science Advances.
“This achievement has been a dream of nanotechnology for the last 20 years,” says Arnold. “Making carbon nanotube transistors that are better than silicon transistors is a big milestone. This breakthrough in carbon nanotube transistor performance is a critical advance toward exploiting carbon nanotubes in logic, high-speed communications, and other semiconductor electronics technologies.”
This advance could pave the way for carbon nanotube transistors to replace silicon transistors and continue delivering the performance gains the computer industry relies on and that consumers demand. The new transistors are particularly promising for wireless communications technologies that require a lot of current flowing across a relatively small area.
As some of the best electrical conductors ever discovered, carbon nanotubes have long been recognized as a promising material for next-generation transistors.
Carbon nanotube transistors should be able to perform five times faster or use five times less energy than silicon transistors, according to extrapolations from single nanotube measurements. The nanotube’s ultra-small dimension makes it possible to rapidly change a current signal traveling across it, which could lead to substantial gains in the bandwidth of wireless communications devices.
But researchers have struggled to isolate purely carbon nanotubes, which are crucial, because metallic nanotube impurities act like copper wires and disrupt their semiconducting properties — like a short in an electronic device.
The UW-Madison team used polymers to selectively sort out the semiconducting nanotubes, achieving a solution of ultra-high-purity semiconducting carbon nanotubes.
“We’ve identified specific conditions in which you can get rid of nearly all metallic nanotubes, where we have less than 0.01 percent metallic nanotubes,” says Arnold.
Placement and alignment of the nanotubes is also difficult to control.
To make a good transistor, the nanotubes need to be aligned in just the right order, with just the right spacing, when assembled on a wafer. In 2014, the UW-Madison researchers overcame that challenge when they announced a technique, called “floating evaporative self-assembly,” that gives them this control.
The nanotubes must make good electrical contacts with the metal electrodes of the transistor. Because the polymer the UW-Madison researchers use to isolate the semiconducting nanotubes also acts like an insulating layer between the nanotubes and the electrodes, the team “baked” the nanotube arrays in a vacuum oven to remove the insulating layer. The result: excellent electrical contacts to the nanotubes.
The researchers also developed a treatment that removes residues from the nanotubes after they’re processed in solution.
“In our research, we’ve shown that we can simultaneously overcome all of these challenges of working with nanotubes, and that has allowed us to create these groundbreaking carbon nanotube transistors that surpass silicon and gallium arsenide transistors,” says Arnold.
The researchers benchmarked their carbon nanotube transistor against a silicon transistor of the same size, geometry and leakage current in order to make an apples-to-apples comparison.
They are continuing to work on adapting their device to match the geometry used in silicon transistors, which get smaller with each new generation. Work is also underway to develop high-performance radio frequency amplifiers that may be able to boost a cellphone signal. While the researchers have already scaled their alignment and deposition process to 1 inch by 1 inch wafers, they’re working on scaling the process up for commercial production.
Arnold says it’s exciting to finally reach the point where researchers can exploit the nanotubes to attain performance gains in actual technologies.
“There has been a lot of hype about carbon nanotubes that hasn’t been realized, and that has kind of soured many people’s outlook,” he says. “But we think the hype is deserved. It has just taken decades of work for the materials science to catch up and allow us to effectively harness these materials.”
University of Wisconsin—Madison engineers have created high-performance, micro-scale solar cells that outshine comparable devices in key performance measures. The miniature solar panels could power myriad personal devices — wearable medical sensors, smartwatches, even autofocusing contact lenses.
Large, rooftop photovoltaic arrays generate electricity from charges moving vertically. The new, small cells, described today (Aug. 3, 2016) in the journal Advanced Materials Technologies, capture current from charges moving side-to-side, or laterally. And they generate significantly more energy than other sideways solar systems.
New-generation lateral solar cells promise to be the next big thing for compact devices because arranging electrodes horizontally allows engineers to sidestep a traditional solar cell fabrication process: the arduous task of perfectly aligning multiple layers of the cell’s material atop one another.
“From a fabrication point of view, it is always going to be easier to make side-by-side structures,” says Hongrui Jiang, a UW–Madison professor of electrical and computer engineering and corresponding author on the paper. “Top-down structures need to be made in multiple steps and then aligned, which is very challenging at small scales.”
Lateral solar cells also offer engineers greater flexibility in materials selection.
Top-down photovoltaic cells are made up of two electrodes surrounding a semiconducting material like slices of bread around the meat in a sandwich. When light hits the top slice, charge travels through the filling to the bottom layer and creates electric current.
In the top-down arrangement, one layer needs to do two jobs: It must let in light and transmit charge. Therefore, the material for one electrode in a typical solar cell must be not only highly transparent, but also electrically conductive. And very few substances perform both tasks well.
Instead of building its solar cell sandwich one layer at a time, Jiang’s group created a densely packed, side-by-side array of miniature electrodes on top of transparent glass. The resulting structure — akin to an entire loaf of bread’s worth of solar-cell sandwiches standing up sideways on a clear plate — separates light-harvesting and charge-conducting functions between the two components.
The miniature solar panels could power myriad personal devices — wearable medical sensors, smartwatches, even autofocusing contact lenses.
Generally, synthesizing such sideways sandwiches is no simple matter. Other approaches that rely on complicated internal nanowires or expensive materials called perovskites fall short on multiple measures of solar cell quality.
“We easily beat all of the other lateral structures,” says Jiang.
Existing top-of the-line lateral new-generation solar cells convert merely 1.8 percent of incoming light into useful electricity. Jiang’s group nearly tripled that measure, achieving up to 5.2 percent efficiency.
“In other structures, a lot of volume goes wasted because there are no electrodes or the electrodes are mismatched,” says Jiang. “The technology we developed allows us to make very compact lateral structures that take advantage of the full volume.”
Packing so many electrodes into such a small volume boosted the devices’ “fill factors,” a metric related to the maximum attainable power, voltage and current. The structures realized fill factors up to 0.6 — more than twice the demonstrated maximum for other lateral new-generation solar cells.
Jiang and colleagues are working to make their solar cells even smaller and more efficient by exploring materials that further optimize transparency and conductivity. Ultimately they plan to develop a small-scale, flexible solar cell that could provide power to an electrically tunable contact lens.
The consumer marketplace is flooded with a lively assortment of smart wearable electronics that do everything from monitor vital signs, fitness or sun exposure to play music, charge other electronics or even purify the air around you — all wirelessly.
Now, a team of University of Wisconsin—Madison engineers has created the world’s fastest stretchable, wearable integrated circuits, an advance that could drive the Internet of Things and a much more connected, high-speed wireless world.
Led by Zhenqiang “Jack” Ma, the Lynn H. Matthias Professor in Engineering and Vilas Distinguished Achievement Professor in electrical and computer engineering at UW–Madison, the researchers published details of these powerful, highly efficient integrated circuits today, May 27, 2016, in the journal Advanced Functional Materials.
The advance is a platform for manufacturers seeking to expand the capabilities and applications of wearable electronics — including those with biomedical applications — particularly as they strive to develop devices that take advantage of a new generation of wireless broadband technologies referred to as 5G.
With wavelength sizes between a millimeter and a meter, microwave radio frequencies are electromagnetic waves that use frequencies in the .3 gigahertz to 300 gigahertz range. That falls directly in the 5G range.
Scientists have created the world’s thinnest lens, one two-thousandth the thickness of a human hair, opening the door to flexible computer displays and a revolution in miniature cameras.
Lead researcher Dr Yuerui (Larry) Lu from ANU Research School of Engineering said the discovery hinged on the remarkable potential of the molybdenum disulphide crystal.
“This type of material is the perfect candidate for future flexible displays,” said Dr Lu, leader of Nano-Electro-Mechanical System (NEMS) Laboratory in the ANU Research School of Engineering.
“We will also be able to use arrays of micro lenses to mimic the compound eyes of insects.”
The 6.3-nanometre lens outshines previous ultra-thin flat lenses, made from 50-nanometre thick gold nano-bar arrays, known as a metamaterial.
“Molybdenum disulphide is an amazing crystal,” said Dr Lu
“It survives at high temperatures, is a lubricant, a good semiconductor and can emit photons too.
“The capability of manipulating the flow of light in atomic scale opens an exciting avenue towards unprecedented miniaturisation of optical components and the integration of advanced optical functionalities.”
Molybdenum disulphide is in a class of materials known as chalcogenide glasses that have flexible electronic characteristics that have made them popular for high-technology components.
Dr Lu’s team created their lens from a crystal 6.3-nanometres thick – 9 atomic layers – which they had peeled off a larger piece of molybdenum disulphide with sticky tape.
They then created a 10-micron radius lens, using a focussed ion beam to shave off the layers atom by atom, until they had the dome shape of the lens.
The team discovered that single layers of molybdenum disulphide, 0.7 nanometres thick, had remarkable optical properties, appearing to a light beam to be 50 times thicker, at 38 nanometres. This property, known as optical path length, determines the phase of the light and governs interference and diffraction of light as it propagates.
“At the beginning we couldn’t imagine why molybdenum disulphide had such surprising properties,” said Dr Lu.
Collaborator Assistant Professor Zongfu Yu at the University of Wisconsin, Madison, developed a simulation and showed that light was bouncing back and forth many times inside the high refractive index crystal layers before passing through.
Molybdenum disulphide crystal’s refractive index, the property that quantifies the strength of a material’s effect on light, has a high value of 5.5. For comparison, diamond, whose high refractive index causes its sparkle, is only 2.4, and water’s refractive index is 1.3.
Learn more: World’s thinnest lens to revolutionise cameras