A Northwestern Univ. study by an economist and a chemist reports that when fuel prices drove residents of São Paulo, Brazil, to mostly switch from ethanol to gasoline in their flexible-fuel vehicles, local ozone levels dropped 20%. At the same time, nitric oxide and carbon monoxide concentrations tended to go up.
One strategy for addressing the world’s energy crisis is to stop wasting so much energy when producing and using it, which can happen in coal-fired power plants or transportation. Nearly two-thirds of energy input is lost as waste heat. Now Northwestern Univ. scientists have discovered a surprising material that is the best in the world at converting waste heat to useful electricity.
Materials scientists have long known that introducing defects into 3-D materials can improve their mechanical and electronic properties. Now a new Northwestern Univ. study finds how defects affect 2-D crystalline structures, and the results hold information for designing new materials.
Researchers at Argonne National Laboratory in collaboration with scientists at Northwestern Univ. are the first to grow graphene on silver which, until now, posed a major challenge to many in the field. Part of the issue has to do with the properties of silver, the other involves the process by which graphene is grown.
Cars inch forward slowly in traffic jams, but molecules, when jammed up, can move extremely fast. New research by Northwestern Univ. researchers finds that water molecules traveling through tiny carbon nanotube pipes do not flow continuously but rather intermittently, like stop-and-go traffic, with unexpected results.
Sometimes solving a problem doesn’t require a high-tech solution. Sometimes, you have to look no farther than your desktop. Three students from Northwestern Univ.’s McCormick School of Engineering have proven that pencils and regular office paper can be used to create functional devices that can measure strain and detect hazardous chemical vapors.
Computational work conducted at Northwestern Univ. has led to a new mathematical theory for understanding the global spread of epidemics. The resulting insights could not only help identify an outbreak’s origin but could also significantly improve the ability to forecast the global pathways through which a disease might spread.
Nature builds flawless diamonds, sapphires and other gems. Now a Northwestern Univ. research team is the first to build near-perfect single crystals out of nanoparticles and DNA, using the same structure favored by nature. The research group developed the “recipe” for using nanomaterials as atoms, DNA as bonds and a little heat to form tiny crystals. This single-crystal recipe builds on superlattice techniques.
Researchers have made inroads into tackling a bacterium that plagues hospitals and is highly resistant to most antibiotics. They determined the 3-D structure and likely function of a new protein in this common bacterium that attacks those with compromised immune systems.
Northwestern Univ. and Argonne National Laboratory scientists have recently overcome problems with growing graphene on chemically inert substrates, demonstrating the first growth of graphene on a single-crystal silver substrate. Their method could advance graphene-based optical devices and enable the interfacing of graphene with other two-dimensional materials.
Fluid jets are all around us: from inkjet printing, to the “Old Faithful” geyser in Yellowstone National Park, to cosmological jets several thousand light years long. A team of researchers has recently verified the classical Landau-Squire theory in the tiniest submerged jet. The diameter of their jets were in the range of 20 to 150 nm, which is the length of just a few hundred water molecules lined up in a row.
As electronics approach the atomic scale, researchers are increasingly successful at developing atomically thin, virtually 2-D materials that could usher in the next generation of computing. Integrating these materials to create necessary circuits, however, has remained a challenge. Northwestern Univ. researchers have now taken a significant step toward fabricating complex nanoscale electronics.
Terahertz radiation is gaining attention due to its many applications. Traditional methods of generating terahertz radiation, however, usually involve large and expensive instruments, some of which also require cryogenic cooling. A compact terahertz source operating at room temperature with high power has been a dream device in the terahertz community for decades. A team from Northwestern Univ. has now brought this dream closer to reality.
A team from the Univ. of Illinois at Urbana-Champaign and Northwestern Univ. has devised a novel nuclear magnetic resonance imaging (MRI) technique that delivers a roughly 10-nm spatial resolution. This represents a significant advance in MRI sensitivity as modern MRI techniques yield spatial resolutions on the millimeter length scale, with the highest-resolution experimental instruments giving spatial resolution of a few micrometers.
A simple kitchen sink experiment helped Northwestern Univ. researchers discover that green tea leaves not only can be used to steep a good cup of tea, but they make an excellent antibacterial coating, too. And so can red wine, dark chocolate and cacao beans, they found. It's the powerful and healthful polyphenols at work in a new way.
Polymer, or plastic, solar cells contain Earth-abundant and environmentally benign materials, can be made flexible and lightweight, and can be fabricated using roll-to-roll technologies. But the cells’ power-conversion efficiency has been limited. A Northwestern Univ. research reports the design and synthesis of new polymer semiconductors a plastic solar cells with fill factors of 80%. This number is close to that of silicon solar cells.
How do fish swim? It is a simple question, but there is no simple answer. Researchers at Northwestern Univ. have revealed some of the mechanical properties that allow fish to perform their complex movements. Their findings could provide insights in evolutionary biology and lead to an understanding of the neural control of movement and development of bio-inspired underwater vehicles.
Picture two light beams intersecting one another in space. When the beams touch one another, does the light bend? Reflect? Combine into a single beam? The answer, of course, is the light beams do nothing; they simply continue on their path. But in certain crystalline materials and with a powerful enough laser, it is possible to make photons interact with one another and take on a special set of characteristics.
Northwestern University researchers have recently developed a graphene-based ink that is highly conductive and tolerant to bending, and they have used it to inkjet-print graphene patterns that could be used for extremely detailed, conductive electrodes. The resulting patterns are 250 times more conductive than previous attempts to print graphene-based electronic patterns and could be a step toward low-cost, foldable electronics.
An international team of scientists using a new X-ray method recorded the internal structure and cell movement inside a living frog embryo in greater detail than ever before. This result showcases a new method to advance biological research and the search for new treatments for genetic diseases.
Bacteria on a surface wander around and often organize into highly resilient communities known as biofilms. It turns out that they organize in a rich-get-richer pattern similar to the distribution of wealth in the U.S. economy, according to a new study.
A team of scientists in the United States has combine three different imaging methods to produce 3D images and videos of a tiny platinum nanoparticle at atomic resolution that reveal new details of defects in nanomaterials that have not been seen before. Prior to this work, scientists only had flat, two-dimensional images with which to view the arrangement of atoms.
President Obama in this year's State of the Union address talked about the future of energy and mentioned "self-healing power grids"—a grid that is able to keep itself stable and self-recover even in severe weather. But as the national power-grid network becomes larger and more complex achieving reliability across the network is increasingly difficult. Scientists have now identified conditions and properties that power companies can consider using to keep power generators in the desired synchronized state and help make a self-healing power grid a reality.
Northwestern University's Chad A. Mirkin, a leading nanotechnology researcher, has developed a completely new set of building blocks that is based on nanoparticles and DNA. Using these tools, which Mirkin presented at the American Association for the Advancement of Science annual meeting in Boston on Feb. 17, scientists will be able to build—from the bottom up, just as nature does—new and useful structures from artificial atoms.
Researchers at Northwestern University have now developed a new design for organic solar cells that could lead to more efficient, less expensive solar power. Instead of attempting to increase efficiency by altering the thickness of the solar cell's polymer layer—a tactic that has preciously garnered mixed results—the researchers sought to design the geometric pattern of the scattering layer to maximize the amount of time light remained trapped within the cell.