New Material Emits Near-Infrared Light For Weeks

Researchers have created a material that can absorb one minute of sunlight and release that energy through near-infrared light for 360 hours, or over two weeks. It can also be charged by indoor lighting. The light it releases is invisible to the human eye, but can be seen with the right equipment. More from PhysOrg:

The material can be fabricated into nanoparticles that bind to cancer cells, for example, and doctors could visualize the location of small metastases that otherwise might go undetected. For military and law enforcement use, the material can be fashioned into ceramic discs that serve as a source of illumination that only those wearing night vision goggles can see. Similarly, the material can be turned into a powder and mixed into a paint whose luminescence is only visible to a select few…

In a process that Pan likens to perfecting a recipe, he and postdoctoral researcher Feng Liu and doctoral student Yi-Ying Lu spent three years developing the material. Initial versions emitted light for minutes, but through modifications to the chemical ingredients and the preparation—just the right amounts of sintering temperature and time—they were able to increase the afterglow from minutes to days and, ultimately, weeks.

“Even now, we don’t think we’ve found the best compound,” Pan said. “We will continuously tune the parameters so that we may find a much better one.”

The researchers spent an additional year testing the material—indoors and out, as well as on sunny days, cloudy days and rainy days—to prove its versatility. They placed it in freshwater, saltwater and even a corrosive bleach solution for three months and found no decrease in performance.

In addition to exploring biomedical applications, Pan’s team aims to use it to collect, store and convert solar energy. “This material has an extraordinary ability to capture and store energy,” Pan said, “so this means that it is a good candidate for making solar cells significantly more efficient.”

Very cool. It sounds like the kind of thing very clever people will find very clever things to do with. 

This material is phosphorescent, which basically means that it emits light like this: photons of light (ex. from the sun) hit electrons in the material. The electrons absorb that energy (generally one electron can absorb one photon) and as a result orbit farther from their atom’s nucleus, better resisting the positive pull of the protons. Eventually the electrons drop back to a less-energetic state that’s closer to the nucleus, and in the process emit their energy back as a photon. This photon is less energetic than the one they first absorbed, so where the sun’s photon was in the visible light range, the emitted photon is, at least in this case, in the near-infrared range.

If all of this happens in one rapid step then it’s called fluorescence, but if the energized electrons take a detour and take a while to emit a photon, it’s called phosphorescence. This is also what happens in fluorescent lightbulbs: electricity causes mercury in the bulbs to emit ultraviolet light, which is more energetic than visible light. This light is absorbed by fluorescent material in the bulbs, then emitted as visible light. In contrast, incandescent lightbulbs emit light because the filament wire inside is heated to a high temperature, causing it to glow. 

Yes, there are awesome things happening in your lightbulbs. Thanks science! Keep in mind though that mercury is toxic, so remember to take your CFLs to the appropriate recycling center instead of trashing them.

The World’s Lightest Material

Via PhysOrg: Researchers have created a material that’s about 100 times as light as styrofoam. 99.99% of it is composed of air, and the other 0.01% is composed very, very carefully.

“The trick is to fabricate a lattice of interconnected hollow tubes with a wall thickness 1,000 times thinner than a human hair,” said lead author Dr. Tobias Schaedler of HRL.

The material’s architecture allows unprecedented mechanical behavior for a metal, including complete recovery from compression exceeding 50 percent strain and extraordinarily high energy absorption.

“Materials actually get stronger as the dimensions are reduced to the nanoscale,” explained UCI mechanical and aerospace engineer Lorenzo Valdevit, UCI’s principal investigator on the project. “Combine this with the possibility of tailoring the architecture of the micro-lattice and you have a unique cellular material.”

Developed for the Defense Advanced Research Projects Agency, the novel material could be used for battery electrodes and acoustic, vibration or shock energy absorption.

This is very interesting. I’m curious about the ratio of lightness to energy absorption (which they pin at “extraordinarily high”) – simplistically, how proportionally strong is it? If you could make armour that weighed as much as a shirt but absorbed a bullet impact, well, that’d be just dandy. However, it seems like future experiments and applications would be limited by the difficulty of creating this material – mass-producing objects with specific features on the nanometre scale is not yet an easy task. The cost, of course, goes without saying. 

So what does that mean? What does it always mean? We wait and see! In 10 years I’ll want my Macbook 99.99% Air. 

The Race to the Next Heaviest Element

There was news recently about some of the heaviest elements getting their new names. How did scientists discover those elements before anyone else? The University of Oslo has an interesting article on the current race to create elements 119 and 120 for the first time (the heaviest element produced to date is 118, temporarily named ununoctium). 

This kind of science is incredibly high pressure; it’s basically all or nothing. If you’ve spent long years of hard work trying to create this element but someone else beats you to it, your work is basically down the toilet. All research is sort of like this, but some types in particular are after one very specific end goal that only one team will get credit for. 

So what do they have to do to win?

The race to create element 119 started two weeks ago when the nuclear physics facility at Oak Ridge National Laboratory in the USA produced 20 mg of the extremely radioactive substance, Berkelium. Berkelium, which must be created artificially in very special nuclear reactors, is heavier than Uranium and extremely difficult to produce in pure concentrations.

Each of the teams of scientists received 10 mg.

In order to create element 119, they will bombard a metal plate laced with Berkelium atoms with a beam of Titanium atoms. The Berkelium has to be used quickly before it disappears. Berkelium is a perishable substance. It has a half-life of 320 days; i.e. half of the Berkelium will have decayed into some other substance after 320 days…

The goal is to induce a Titanium atom to fuse together with a Berkelium atom.

Titanium has an atomic number of 22. Berkelium has an atomic number of 97. Together, these two atoms have a total of 119 protons; i.e. exactly the right number to create an atom of element 119…

“When the atoms collide with each other on rare occasions, they are usually merely shattered or partly destroyed in the collision.

“However, less than once a month, we will get a complete atom. The probability of doing so is lower than the chance of winning the jackpot in Lotto. The problem is that you will have to detect this one atom on a metal plate where more than 100,000 superfluous events are occurring each second.” …

The only way to do this is to measure the radioactive radiation at the moment when the atom decays.

“This means that we cannot detect the atom by measurement until it is gone. Not before that!” …

The surest way to detect the atom is to examine all of its “daughters” when it decays.
Such a chain of fissions may progress in five to eight steps. The scientists can only be certain that they have found the new element when the chain of reactions occurs in a particular way.

Damn. It sounds really difficult, although I’m glad it’s a simple enough idea for us laypeople to follow. Smash atom 97 and atom 22 together to make atom 119. This begs the question, of course, of why they’d pick this combination and not the other 50+ possible two-atom combos. I’m guessing that’s where the complications that we wouldn’t understand come in, so we’ll have to be happy with what we see here. 

Three New Elements Named

If you remember your periodic table (and why wouldn’t you?), you may remember some oddly named elements at the highest numbers – ununnilium, unununium, and ununbium, for example. These were placeholder names simply describing their atomic number, but now they’ve finally got names of their own. 

From LiveScience:

The periodic table of elements just got a bit heftier today (Nov. 4), as the names of three new elements were approved by the General Assembly of the International Union of Pure and Applied Physics.

Elements 110, 111 and 112 have been named darmstadtium (Ds), roentgenium (Rg) and copernicium (Cn).

Temporarily called ununbium, copernicium, the new element 112, was named for Polish astronomer Nicolaus Copernicus (1473-1543), who first suggested that the Earth revolves around the sun, not the other way around, and starting the “Copernican Revolution.” In a statement released in July 2009, Sigurd Hofmann, head of the discovery team at GSI Helmholtz Centre for Heavy Ion Research in Germany, said they named the element after Copernicus “to honor an outstanding scientist, who changed our view of the world.”

… Element number 111, officially renamed roentgenium by the General Assembly, was originally discovered in 1994 when a team at GSI created three atoms of the element, about a month after their discovery of darmstadtium, on Dec. 8…

Roentgenium was named after German physicist Wilhelm Conrad Roentgen (1845 – 1923), ridding itself of its temporary name unununium, Roentgen was the first to produce and detect X-rays, on Nov. 8 1895. He won the Nobel Prize in physics in 1901 for the work.

Darmstadtium, the new element 110, which took the temporary name ununnilium, was first synthesized on Nov. 9, 1994, at the GSI facility near the city of Darmstadt…

None of these exist in nature; they can only be created, with great difficulty of course, in a lab, and they’re so large that they quickly come apart into smaller elements. Thanks to these names the periodic table got a little less weird, but we still have ununtrium, ununquadium, ununpentium, ununhexium, ununseptium and ununoctium in need of names. Newtonium, anyone? Maybe some Canadium? No?

Complex Organic Compounds in Space

Researchers have discovered that stars are capable of creating more complex organic compounds than previously thought possible. This ties in pretty nicely with the previous post, since it’s thought that asteroids may have brought organic compounds to Earth and played a role in the origin of life. 

From PhysOrg (but check out Space.com for a less succinct but better article):

The researchers investigated an unsolved phenomenon: a set of infrared emissions detected in stars, interstellar space, and galaxies. These spectral signatures are known as “Unidentified Infrared Emission features”. For over two decades, the most commonly accepted theory on the origin of these signatures has been that they come from simple organic molecules made of carbon and hydrogen atoms, called polycyclic aromatic hydrocarbon (PAH) molecules. From observations taken by the Infrared Space Observatory and the Spitzer Space Telescope, Kwok and Zhang showed that the astronomical spectra have features that cannot be explained by PAH molecules. Instead, the team proposes that the substances generating these infrared emissions have chemical structures that are much more complex. By analyzing spectra of star dust formed in exploding stars called novae, they show that stars are making these complex organic compounds on extremely short time scales of weeks.

Not only are stars producing this complex organic matter, they are also ejecting it into the general interstellar space, the region between stars. The work supports an earlier idea proposed by Kwok that old stars are molecular factories capable of manufacturing organic compounds. “Our work has shown that stars have no problem making complex organic compounds under near-vacuum conditions,” says Kwok. “Theoretically, this is impossible, but observationally we can see it happening.”

I like how this can be seen as an astronomy, physics, chemistry or evolutionary biology discovery, depending on your focus. It may really be all of them. The idea of stars creating (relatively) complex organic compounds is pretty crazy, and will definitely fuel the idea that life probably developed elsewhere in the universe as well as here.

To be clear, the compounds they’re talking about are not anything on the scale of proteins or genetic material, but simpler molecules than those are enough to form a membrane, which is a prerequisite to life as we know it (since you need an “inside” of a living thing and an outside). There’s a manned mission to an asteroid coming up in the near future; maybe we’ll find something totally unexpected?

2011 Nobel Prize Recap

It’s that time! Time to go over this year’s science Nobel Prize winners. Keep in mind that a maximum of 3 people are awarded a prize, whereas there can be a large number of other contributing individuals who aren’t recognized. Science is generally and increasingly a very collaborative business.

Nobel Prize in Physiology or Medicine: Bruce Beutler, Jules Hoffman and Ralph Steinman, for their discoveries about the immune system. The first two discovered the Toll system, an integral part of the innate immune system (which I discussed earlier). Without the Toll protein or its receptor, “organisms are extremely vulnerable to infection.” Ralph Steinman, who sadly passed away a few days before receiving the prize, discovered the important role of a type of cell called dendritic cells in transmitting information between the innate immune system and the adaptive immune system, allowing it to “remember” invaders.

Nobel Prize in Physics: Adam Riess, Brian Schmidt and Saul Perlmutter, for discovering that the expansion of the universe was speeding up. This was a huge revolution in our understanding of the universe; until then, it was assumed that the expansion of the universe was slowing due to the force of gravity. To explain it, a mysterious “dark energy” was hypothesized to be working against the force of gravity, I guess in line with the nomenclature of “dark matter” to explain the mysterious source of gravity in the universe not attributable to regular matter. 

Interestingly, just a few days ago another possible explanation to replace dark energy was published, called “dark flow“. It posits that the movement of our own galaxy is skewing our measurements of the rest of the universe’s acceleration, and that the accelerating expansion is actually illusory. It doesn’t seem to be as strong of an explanation as dark energy yet, but maybe it will be eventually. 

Nobel Prize in Chemistry: Daniel Schechtman, for the discovery of quasicrystals, “materials that have ordered but not periodic structures”. He found that molecules could be organized in ways previously thought impossible, and there was a ton of resistance against his discoveries that he had to painfully overcome; notably, he won the award individually, since it seems like no one else would touch his research. You should read this Physics World article on it, it’s pretty interesting. 

Well! There we have it, for this year. Apparently every year there’s controversy about the Nobel Prizes; about the 3-person cap on awards, about the outdated categories… I actually was surprised at the categories myself. Science has changed a lot in the last 116 years; the most prominent awards in science should try to keep up.

“Diamonds are for everything”

I was a bit skeptical at first about this article from Chemistry World, broadly about the uses of diamonds. Why do I care about diamonds? It’s actually pretty cool though; it explains in just the right amount of detail a wide variety of modern and emerging applications of diamonds, from making better solar panels, to single-photon lasers, to stable windows for missions to Venus.

I don’t want to summarize all these summaries of applications, since I think they’re already written pretty succinctly and well, so go check out the article if you want some insight into emerging technology in quite a variety of fields.

With diamonds getting easier to create in a lab, I wonder what the diamond market and culture will look like in 50 years? Many a young fiancé may be in better luck than our generation.

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