Archive for Peking University
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You are browsing the archives of Peking University.
Background image: Molten glass. Credit: Michael Germann; Dreamstime.com.
Peter and I thought it would be fun to share our five favorite posts from 2012. Finding that choosing only five was nigh impossible, I decided to sort my picks into three categories, which instantly grew my budget to 15 stories!
Advances in science and engineering are subject to forces beyond physics, chemistry, and mathematics, such as politics, culture, history, and more.
USPTO issues flurry of new rules to implement ‘America Invents Act’
Archaic US patent rules were thrown out with adoption of the Leahy-Smith America Invents Act. New rules, though, mean changes in the strategy of innovation.
Data drives engineering of ceramics; workshop asks ‘how well?’
Computational approaches to materials engineering are only as good as the data they consume and digest. A DOD-sponsored workshop evaluated the state-of-affairs for electronic access to ceramic property data and the attendant challenges and opportunities.
Science research drives economic growth, but it’s expensive and slow
What role should governments take in investing in basic research, and how does a nation’s R&D investment impact GDP? There is nothing like an election year—in the US and abroad—to draw attention to what governments should spend money on versus what they do spend money on.
Video: Grand challenges in ceramic science—Preliminary findings from workshop
Researchers go bravely where others cannot or dare not. A group of the nation’s top ceramic science researchers convened to tease out the largest scientific challenges that can be addressed with ceramic materials.
Historic January 1987: YBCO superconductors discovered and Super Bowl XXI
This story about the discovery of high-temperature YBCO superconductors shows that research breakthroughs are often the progeny of systematic, well-executed fundamental research… and serendipity.
I’m an unabashed materials geek, and these were some of my favorite super-sciency stories—with the qualification that I mostly write about science that intrigues me, so this is a lot like choosing a favorite child.
Understanding the ‘between’ spaces: Interfacial phases and solid-state sintering
The formation and stability of interfacial phases in the solid state drives properties, so understanding how interfaces form and the thermodynamics driving them is of paramount importance.
Mullite-like mixed oxides may replace platinum for catalyzing diesel pollution
Manganese-oxide compounds with the mullite crystal structure may one day displace platinum as the catalyst agent in automobile catalytic converters.
High-alumina optical fibers get around Brillouin scattering limitations
Ever wonder how data gets to your smart phone or laptop so fast? A group of glass scientists is working on the next generation on optical fibers that will move more data, faster, and with more accuracy.
High critical current density doped pnictide superconductors
Harnessing the promise of high-temperature superconductivity requires a deep understanding of the physics of magnetism and the influences of composition and microstructure. Plus, what’s not to love about the word “pnictide?”
Heat transfer—two new studies look at effects of interface bonding, surface roughness
The digital age is generating some very sophisticated heat transfer challenges. How exactly does heat egress from a surface, and how can the mechanism be engineered?
Useful metrics for comparing new energy storage technologies
Measuring is an essential experimental activity. However, scientists and engineers must continually ask themselves the question, “Am I measuring something meaningful and useful?”
And this last group of five was just fun to write about.
Don’t wait in line for coffee: How to know where the business opportunity is
A reflection on business, opportunity, finding the way, and waiting in line.
Oldest known pottery dates back 20,000 years and may have changed the course of human history
The earliest ceramic engineers designed pots for cooking and brewing, proof that since time immemorial, engineers bring the life of the party. Literally.
Friday fun video—Gravity-defying Slinky
Adulthood does not mean toys become irrelevant. This video shows that scientists never stop learning the lessons that educational toys can teach.
Technical ceramics and art ceramics—only a brain apart
In the world of ceramics, is there a line between art and science? Yes, sort of—and no, not really. The American Ceramic Society serves the professional needs of engineers, scientists, studio artists, and hobbyists.
A castle vacation, poster session included
An October vacation to Germany included a conference at a Bavarian castle and the opportunity to talk shop with some of the best minds in the world working on biomineralization.
Were you counting? Me neither. Did you have a favorite story or topic that we covered? Let us know!
Best wishes for a Happy New Year!
These beautiful ceramic roasters by artist Robbie Lobell continue an ancient tradition of using pottery for cooking. Lobell intends for her roasters to be used, “I make my flameware pots to encourage the ideas of using handmade objects to prepare and present locally grown vegetables, fruits and meats from our gardens, barnyards and nearby farms.” Her fellow potters from 20,000 years ago may have had similar motivations, but changed the course of human history, too. Credit: Robbie Lobell.
Our nation’s annual Independence Day holiday is next Wednesday, and perhaps, like me, you are thinking about holiday get-togethers and what to bring to the neighborhood potluck. Once that is decided, the next question is what container to use.
Apparently, what pot to bring to the potluck is a much older question than previously thought.
A new paper in Science reports on the discovery that ancient pottery found in the Xianrendong Cave, Jiangxi Province in China date back about 20,000 to 19,000 years. This is 2,000 to 3,000 years earlier than other pottery fragments from East Asia and other locations.
The international research team of researchers from Peking University, Boston University, Eberhard Karls University Tübingen and Harvard University used radiocarbon measurements to date fragments of a pot that is estimated to have once been about 20 centimeters tall and 15-25 centimeters wide.
In our modern perspective, we do not think of pottery as an engineered material, but for our cave-dwelling ancestors, it was. The opening sentence of the paper explains.
Pottery making—the manufacture of fired, ceramic container forms—differs considerably from the baked clay figurines or small objects known from the Upper Paleolithic period in its technological demands and in its significance both in subsistence activities, including food storage, processing, and cooking, and in social interactions.
Previously, it had been thought that pottery was an innovation of the agrarian lifestyle, but the authors dispel that notion.
Pottery making introduces a fundamental shift in human dietary history, and Xianrendong demonstrates that hunter-gatherers in East Asia used pottery for some 10,000 years before they became sedentary or began cultivating plants. The age for pottery production at Xianrendong of ~20,000 years ago coincides with the peak period of the last ice age, when there was a decrease in the productivity of regional food resources. When used for cooking, pottery allows energy gains from starch-rich food as well as meat, and scorch and soot marks on sherd exterior surfaces indicate that Xianrendong pottery likely was used for cooking.
The exact function of this ancient pottery is unknown, but the authors speculate that it may have been used to extract marrow and grease, or in ways that later hunter-gatherer societies used pottery, for example, for food preparation and storage and alcohol brewing.
The development of ancient pottery may have been a turning point in the evolution of our modern lifestyles. The article concludes,
Thus, the early invention of pottery may have played a key role in human demographic and social adaptations to climate change in East Asia, leading to sedentism, and eventually to the emergence of wild rice cultivation during the early Holocene.
In a BBC News article, Hebrew University professor, Gideon Shelach, suggests there may have been a social driver, too. “People were gathering together in larger groups and you needed social activities to mitigate against increased tensions,” he said in the article, and “Maybe those potteries were used to brew alcohol.”
Something to think about as you bake your macaroni and cheese casserole and pick up a carton of Sam Adams on your way to the picnic this week.
The paper is “Early Pottery at 20,000 Years Ago in Xianrendong Cave, China,” Wu, et al., Science (doi: 10.1126/science.1218643)
Chinese scientists say they have figured out a way to turn carbon nanotubes into a superabsorbing and reusable sponge for organic materials. They predict their CNT sponge material may be particularly valuable in applications such as oil spills on ocean, lake and river surfaces because the material won’t absorb water. Their work is reported in Advanced Materials.
Led by Peking University’s Anyuan Cao and Tsinghua University’s Dehai Wu, the group writes in the journal that “the sponges have new properties that integrate the merits of fragile aerogels with their high surface area [the lowest density solid material known is an aerogel], and conventional soft materials with their robustness and flexibility.”
Cao and Wu claim that their CNT material is rugged, elastic, lightweight and can absorbing up to 180 times its own weight in organic matter. This compares very favorably with commercial cellulose-, resin-, polymer- or ceramic-based absorbent materials that typically absorb a fraction of that amount and, furthermore, have to go through heat or some other chemically processing to release the oils or solvents they soak up. They say their sponge material can literally release its contents with simple squeezing, allowing the sponge to be reused and the contents recovered.
According to their paper, Cao and Wu’s sponges are basically CNTs 30–50 nanometers in diameter and tens to hundreds of micrometers long. They exploit the nanotubes’s surface affinity for organic materials and hydrophobicity, and the low density allows the sponge material to float easily on water.
The CNTs are formed via chemical vapor deposition and self-assembly. They say the secret is allow the creation of random arrays of long nanotubes. This lets the nanotubes glide by each other, and maintain flexibility and elasticity. They also say the sponge effect works best if they are first primed with a solvent and then squeezed down. Material given this densification treatment (see video below) can be reduced to a pellet size. When put into use, even at the edge of a spill, they report that, “A small densified pellet of sponge can quickly remove a spreading diesel oil film with an area up to 800 times that of the sponge.”
They report some example capacities: 143 times the sponge’s weight for diesel oil and 175 for ethylene glycol.
Cao imagines many other applications. “The nanotube sponges can be used as filters, membranes, or absorbents to remove bacteria or contaminants from liquid or gas. They could also be used as noise-absorption layers in houses, and soldiers might benefit by using these sponges in impact energy absorbing components while adding little weight. Thermally insulated clothing is also possible.”
Here is a video of how the flexible CNT material can be squeezed down: