At the chemical level, diamonds are no more than carbon atoms aligned in a precise, three-dimensional (3D) crystal lattice. However, even a seemingly flawless diamond contains defects: spots in that lattice where a carbon atom is missing or has been replaced by something else. Some of these defects are highly desirable; they trap individual electrons…
Engineer’s ‘Metallic Wood’ Has Strength of Titanium and Density of Water
High-performance golf clubs and airplane wings are made out of titanium, which is as strong as steel but about twice as light. These properties depend on the way a metal’s atoms are stacked, but random defects that arise in the manufacturing process mean that these materials are only a fraction as strong as they could…
Engineers 3D Print Smart Objects with ‘Embodied Logic’
Even without a brain or a nervous system, the Venus flytrap appears to make sophisticated decisions about when to snap shut on potential prey, as well as to open when it has accidentally caught something it can’t eat. Researchers at the University of Pennsylvania’s School of Engineering and Applied Science have taken inspiration from these…
Engineers Develop Ultrathin, Ultralight ‘Nanocardboard’
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure Now, a team of Penn Engineers has demonstrated a new material they call “nanocardboard,” an…
To Drop CO2 Emissions, Look to Local Transportation and Housing
Worldwide, the United States is one of the biggest greenhouse gas emitters. The Obama administration began efforts to drop those numbers by increasing vehicle fuel economy standards in 2011 and with its Clean Power Plan proposals in 2015. But even if implemented as planned, which is uncertain given the current Administration’s energy-policy agenda, that two-pronged…
Engineers Develop First Transistors Made Entirely of Nanocrystal ‘Inks’
The transistor is the most fundamental building block of electronics, used to build circuits capable of amplifying electrical signals or switching them between the 0s and 1s at the heart of digital computation. Transistor fabrication is a highly complex process, however, requiring high-temperature, high-vacuum equipment. Now, University of Pennsylvania engineers have shown a new approach…
Researcher Illustrates Impact of Drone Usage in Areas of Conflict
The use of drones has had significant consequences for how governments conduct counter-terrorism operations. But technological limitations mean they are less likely to effect wars between countries, according to a new paper co-authored by Michael C. Horowitz, a political scientist at the University of Pennsylvania. In “The Consequences of Drone Proliferation: Separating Fact from Fiction,”…
Engineers Show How ‘Perfect’ Materials Begin to Fail
Crystalline materials have atoms that are neatly lined up in a repeating pattern. When they break, that failure tends to start at a defect, or a place where the pattern is disrupted. But how do defect-free materials break? Until recently, the question was purely theoretical; making a defect-free material was impossible. Now that nanotechnological advances…
Commonalities in How Different Glassy Materials Fail
Glass is mysterious. It is a broad class of materials that extends well beyond the everyday window pane, but one thing that these disparate glasses seem to have in common is that they have nothing in common when it comes to their internal structures, especially in contrast with highly ordered and patterned crystals. Glassy systems…
Large Scale Graphene Production
Draw a line with a pencil and it’s likely that somewhere along that black smudge is a material that earned two scientists the 2010 Nobel Prize in Physics. The graphite of that pencil tip is simply multiple layers of carbon atoms; where those layers are only one atom thick, it is known as graphene. Read:…
Understanding Graphene’s Electrical Properties on an Atomic Level
Graphene, a material that consists of a lattice of carbon atoms, one atom thick, is widely touted as being the most electrically conductive material ever studied. However, not all graphene is the same. With so few atoms comprising the entirety of the material, the arrangement of each one has an impact on its overall function.…