The American Chemical Society (ACS) has produced a video titled, “How that ‘old book smell’ could save priceless artifacts” according to their Sept. 6, 2016 news release on EurekAlert,
Odor-detecting devices like Breathalyzers have been used for years to determine blood-alcohol levels in drunk drivers. Now, researchers are using a similar method to sniff out the rate of decay in historic art and artifacts. By tracking the chemicals in “old book smell” and similar odors, conservators can react quickly to preserve priceless art and artifacts at the first signs of decay. In this Speaking of Chemistry, Sarah Everts explains how cultural-heritage science uses the chemistry of odors to save books, vintage jewelry and even early Legos. …
Here’s the video,
Heritage Smells, the UK project mentioned in the video, is now completed but it was hosted by the University of Strathclyde and more project information can be found here.
Physicists at the University of Kansas have fabricated an innovative substance from two different atomic sheets that interlock much like Lego toy bricks. The researchers said the new material — made of a layer of graphene and a layer of tungsten disulfide — could be used in solar cells and flexible electronics. …
Hsin-Ying Chiu, assistant professor of physics and astronomy, and graduate student Matt Bellus fabricated the new material using “layer-by-layer assembly” as a versatile bottom-up nanofabrication technique. Then, Jiaqi He, a visiting student from China, and Nardeep Kumar, a graduate student who now has moved to Intel Corp., investigated how electrons move between the two layers through ultrafast laser spectroscopy in KU’s Ultrafast Laser Lab, supervised by Hui Zhao, associate professor of physics and astronomy.
“To build artificial materials with synergistic functionality has been a long journey of discovery,” Chiu said. “A new class of materials, made of the layered materials, has attracted extensive attention ever since the rapid development of graphene technology. One of the most promising aspects of this research is the potential to devise next-generation materials via atomic layer-level control over its electronic structure.”
According to the researchers, the approach is to design synergistic materials by combining two single-atom thick sheets, for example, acting as a photovoltaic cell as well as a light-emitting diode, converting energy between electricity and radiation. However, combining layers of atomically thin material is a thorny task that has flummoxed researchers for years.
“A big challenge of this approach is that, most materials don’t connect together because of their different atomic arrangements at the interface — the arrangement of the atoms cannot follow the two different sets of rules at the same time,” Chiu said. “This is like playing with Legos of different sizes made by different manufacturers. As a consequence, new materials can only be made from materials with very similar atomic arrangements, which often have similar properties, too. Even then, arrangement of atoms at the interface is irregular, which often results in poor qualities.”
Layered materials such as those developed by the KU researchers provide a solution for this problem. Unlike conventional materials formed by atoms that are strongly bound in all directions, the new material features two layers where each atomic sheet is composed of atoms bound strongly with their neighbors — but the two atomic sheets are themselves only weakly linked to each other by the so-called van der Waals force, the same attractive phenomenon between molecules that allows geckos to stick to walls and ceilings.
“There exist about 100 different types of layered crystals — graphite is a well-known example,” Bellus said. “Because of the weak interlayer connection, one can choose any two types of atomic sheets and put one on top of the other without any problem. It’s like playing Legos with a flat bottom. There is no restriction. This approach can potentially product a large number of new materials with combined novel properties and transform the material science.”
Chiu and Bellus created the new carbon and tungsten disulfide material with the aim of developing novel materials for efficient solar cells. The single sheet of carbon atoms, known as graphene, excels at moving electrons around, while a single-layer of tungsten disulfide atoms is good at absorbing sunlight and converting it to electricity. By combining the two, this innovative material can potentially perform both tasks well.
The team used scotch tape to lift a single layer of tungsten disulfide atoms from a crystal and apply it to a silicon substrate. Next, they used the same procedure to remove a single layer of carbon atoms from a graphite crystal. With a microscope, they precisely laid the graphene on top of the tungsten disulfide layer. To remove any glue between the two atomic layers that are unintentionally introduced during the process, the material was heated at about 500 degrees Fahrenheit for a half-hour. This allowed the force between the two layers to squeeze out the glue, resulting in a sample of two atomically thin layers with a clean interface.
Doctoral students He and Kumar tested the new material in KU’s Ultrafast Laser Lab. The researchers used a laser pulse to excite the tungsten disulfide layer.
“We found that nearly 100 percent of the electrons that absorbed the energy from the laser pulse move from tungsten disulfide to graphene within one picosecond, or one-millionth of one-millionth second,” Zhao said. “This proves that the new material indeed combines the good properties of each component layer.”
The research groups led by Chiu and Zhao are trying to apply this Lego approach to other materials. For example, by combining two materials that absorb light of different colors, they can make materials that react to diverse parts of the solar spectrum.
This post has been almost two years in the making, which seems laughable when considering that the story starts in 100 BCE (before the common era).
Picture ancient Greece and a Roman sailing ship holding an object we know as an Antikythera, named after the Greek island near where the ship was wrecked and where it lay undiscovered until 1900. From the Dec.10, 2010 posting by GrrlScientist on the Guardian science blogs,
Two years ago [2008], a paper was published in Nature describing the function of the oldest known scientific computer, a device built in Greece around 100 BCE. Recovered in 1901 from a shipwreck near the island of Antikythera, this mechanism had been lost and unknown for 2000 years. It took one century for scientists to understand its purpose: it is an astronomical clock that determines the positions of celestial bodies with extraordinary precision. In 2010, a fully-functional replica was constructed out of Lego.
Here’s the video mentioned by Grrl Scientist,
As noted in the video, it is a replica that requires twice as many gears as the original to make the same calculations. It seems we still haven’t quite caught up with the past.
Bob Yirka’s April 4, 2011 article for phys.org describes some of the research involved in decoding the mechanism,
If modern research is correct, the device worked by hand cranking a main dial to display a chosen date, causing the wheels and gears inside to display (via tabs on separate dials) the position of the sun, moon, and the five known planets at that time, for that date; a mechanical and technical feat that would not be seen again until the fourteenth century in Europe with precision clocks.
…
Now James Evans and his colleagues at the University of Puget Sound in Washington State, have shown that instead of trying to use the same kind of gear mechanism to account for the elliptical path the Earth takes around the sun, and subsequent apparent changes in speed, the inventor of the device may have taken a different tack, and that was to stretch or distort the zodiac on the dial face to change the width of the spaces on the face to make up for the slightly different amount of time that is represented as the hand moves around the face.
In a paper published in the Journal for the History of Astronomy, Evans describes how he and his team were able to examine x-rays taken of the corroded machine (69 then later 88 degrees of the circle) and discovered that the two circles that were used to represent the Zodiac and Egyptian calendar respectively, did indeed differ just enough to account for what appeared to be the irregular movement during different parts of the year.
Though not all experts agree on the findings, this new evidence does appear to suggest that an attempt was made by the early inventor to take into account the elliptical nature of the Earth orbiting the sun, no small thing.
Jenny Winder’s June 11, 2012 article for Universe Today and republished on phys.org provides more details about the gears and the theories behind the device,
The device is made of bronze and contains 30 gears though it may have had as many as 72 originally. Each gear was meticulously hand cut with between 15 and 223 triangular teeth, which were the key to discovering the mechanism’s various functions. It was based on theories of astronomy and mathematics developed by Greek astronomers who may have drawn from earlier Babylonian astronomical theories and its construction could be attributed to the astronomer Hipparchus or, more likely, Archimedes the famous Greek mathematician, physicist, engineer, inventor and astronomer. … [emphases mine]
I’ve highlighted the verbs which suggest they’re still conjecturing as to where the theories and knowledge to develop this ancient computer came from. Yirka’s article mentions that some folks believe that the Antikythera may be the result of alien visitations, along with the more academic guesses about the Babylonians and the Greeks.
I strongly recommend reading the articles and chasing down more videos about the Antikythera on Youtube as the story is fascinating and given the plethora of material (including a book and website by Jo Marchant, Decoding the Heavens), I don’t seem to be alone in my fascination.
There seems to be a race to get our clothes electrified so we can become portable recharging devices. From the news item on Azonano,
In research that gives literal meaning to the term “power suit,” University of California, Berkeley, engineers have created energy-scavenging nanofibers that could one day be woven into clothing and textiles.
These nano-sized generators have “piezoelectric” properties that allow them to convert into electricity the energy created through mechanical stress, stretches and twists.
“This technology could eventually lead to wearable ‘smart clothes’ that can power hand-held electronics through ordinary body movements,” said Liwei Lin, UC Berkeley professor of mechanical engineering and head of the international research team that developed the fiber nanogenerators.
This announcement is on the heels of a similar announcement (noted in my posting of Jan.22.10 here) from researchers at the University of Stanford in California.
Meanwhile, scientists at the University of Calgary are playing with construction toys (they use the lego metaphor, which seems quite popular right now). From the news release on the University of Calgary website (thanks to Azonano where I first found notice of the item),
While many of us enjoyed constructing little houses out of toy bricks, this task is much more difficult if the bricks are elementary particles. It is even harder if these are particles of light—photons—which can only exist while flying at an incredible speed and vanish if they touch anything.
Yet a team at the University of Calgary has accomplished exactly that. By manipulating a mysterious quantum property of light known as entanglement, they are able to mount up to two photons on top of one another to construct a variety of quantum states of light—that is, build two-story quantum toy houses of any style and architecture.
The research has just (yesterday, Feb.14.10) been published in Nature Photonics. You can read the abstract (here after you scroll down) but the rest of the article is behind a paywall.
I found something rather odd this morning about Raymor Industries. It’s a Canadian nanotechnology company (their products are based on single-walled carbon nanotubes) traded on the TSX that is currently experiencing difficulty with, at least some, shareholders. From the item on PRNewsWire,
RAYMOR INDUSTRIES INC. (TSX Venture RAR, RAYRF) is a leading Canadian developer of high technology and a producer of advanced materials and nanomaterials for high value-added applications. Raymor holds the exclusive rights to more than 20 patents throughout the world, with other patents pending. Shareholders have formed a group to fight to protect our shareholder rights and prevent the current board of directors from delisting and the eliminating the common shares of the corporation. The group is called The Raymor Investors Special Action Group. The group is sending out this communication to get the attention of the 8000 shareholders and advise them that an appeal to the recent January 27, 2010 court ruling has been launched and is underway. A strong and reasonable chance exists that the appeal can be won.
If you’re curious about the company and its products, you can read more here at their website, although they offer no additional information about the contretemps.