Posts Tagged ‘chemistry’
New Theory on World Trade Center Collapse Blames Explosive Chemical Reaction
Molten aluminum mixing with water could have ultimately brought the towers down
Simensen’s idea, presented at a materials technology conference in San Diego this week, is thus: after the planes impacted the WTC towers, tons of molten aluminum ran down into the floors below the impact sites, mingling with several hundred liters of water from the buildings’ fire sprinkler systems. This mix of aluminum and water is known to cause a chemical reaction that can not only boost temperatures but also put off combustible hydrogen in the process. Basically, it’s a recipe for a really hot explosion.
The official 9/11 report assigns blame for the collapsing towers to the steel structural beams at the building’s core. Basically, it says that these beams became super-heated by the jet fuel inferno created by the impacting aircraft, and that in turn caused the structures to fail.
But Simensen’s explanation is intriguing. It doesn’t dismiss the official report, but simply claims that it doesn’t tell the whole story. He says the aluminum industry has recorded more than 250 water-aluminum explosions since 1980, and that at one point aluminum maker Alcoa did an experiment involving just 44 pounds of molten aluminum and 20 liters of water (along with a small quantity of rust, which exacerbates the reaction). The resulting explosion destroyed the lab and left a 100-foot crater, he says.
That was under controlled conditions, but extrapolate that to the uncontrolled conditions inside the WTC towers just after the attacks. Jet fuselages contain roughly 33 tons aluminum alloy that melts at roughly 1,220 degrees, Simensen says, turning to a water-like liquid at nearly 1,400 degrees. When the aircraft hit, they exploded and were immediately trapped between floors where debris like plaster quickly melted around them, creating a kind of insulated oven that would push temperatures well north of aluminum’s melting point.
That melted aluminum would then have run down to lower floors, where sprinkler systems were pumping water onto the floors. Once mixed, water and aluminum would’ve immediately reacted, boosting temperatures to up to 2,700 degrees and putting off explosive hydrogen. Thus, just as the steel supports were weakening as a result of the spiking temperatures, the hydrogen blasts would’ve been strong enough and hot enough to blow out a section of the building. That confluence of factors could have easily led to the “pancaking” of the floors above that eventually brought the buildings to their horrifying ends.
Knowing next to nothing about aluminum-water reactions, we’re not out to endorse Simensen’s theory. But it does address some loose ends, like the appearance of explosions from inside the buildings as they began their final collapses. The half hour to 45 minutes that such an aluminum meltdown would require also is roughly consistent with the time elapsed between the impacts and the collapses, Simensen says (once again, we’re not endorsing said math, just reporting what he said).
At this point we’ll never really know what happened. All the same, it’s an interesting bit of chemistry to think about.
[]
Scientists Transform Acids Into Bases, Defying Chemistry Rules
If you took more advanced chemistry, you might have learned that bases are substances that can donate electron pairs, and that acids are substances that can accept them. The point is that the two types of chemicals are polar opposites. Until now, according to researchers at the University of California-Riverside, who have successfully .
Specifically, they have made boron compounds behave like phosphorus catalysts, by modifying the number and location of the electrons in boron without altering the atom’s nucleus.
The goal was not just to turn chemical rules upside down, but to that are less toxic and have useful properties. Catalysts are used to facilitate chemical reactions without being consumed or altered in the reaction. Catalysts have to be bases, but phosphorus-based ones are toxic to end products. Boron compounds can be made to act like bases, but they're unstable.
Rei Kinjo and colleagues at UCR stabilized one of these compounds by adding a carbene, which donated some more electrons. The stabilized borylene could then be used as a catalyst.
“It’s almost like changing one atom into another atom,” said , a UCR chemistry professor who co-authored a paper on the new compound.
The new stabilized borylene could be used to produce a suite of new, non-toxic chemical catalysts, which could be used to make new materials and even new pharmaceuticals. The results were published Friday in the journal .
[]
Years After Crash Landing in 2004, NASA’s Genesis Reveals Data About Solar Chemistry
The most recent finding: Earth’s chemistry is quite different from the sun’s. That may sound obvious, but it actually goes against what cosmologists thought. When our solar system formed 4.6 billion years ago, it did so from churning disk of dust and gas. And because everything came from the same stuff, researchers assumed that the inner solar system would have a shared chemistry.
It turns out that’s not entirely the case. According to the researchers still skimming evidence from Genesis’s wreckage, the Earth is enriched with two isotopes of oxygen and one isotope of nitrogen compared with the sun. That shakes up our origin story quite a bit.
To figure all this out, scientists had to invent whole new methods of cleaning the leftovers of Genesis to remove Earthly contamination from the particles captured in space. It wasn’t easy (it took this long), but teams in America and Europe have managed to isolate pristine samples and analyze them, finding that Earth is richer in both oxygen-17 and oxygen-18 than the sun. The nitrogen disparity is even more pronounced: the sun is roughly 40 percent poorer in nitrogen-15 than the Earth.
Now cosmologists have to figure out why. They have some theories, but in the meantime Genesis science continues to slog along slowly. There were 18 measurements researchers planned to analyze from Genesis’s haul before the crash slowed their progress. Seven years later, they’ve checked off about five and are still working on the rest.
[]
Largest DNA-Based Computer Ever Built Can Calculate Square Roots
Researchers at Caltech engineered the most complex biochemical circuit ever created from scratch, according to a new paper published today. The circuit uses DNA instead of electronic transistors to produce the on-off, and-or signals that allow a computer to conduct its calculations.
In a typical computer, transistors let a current of electrons flow in and out. The DNA computer instead uses pieces of short, single-stranded DNA or partially double-stranded DNA placed in a test tube of salt water. The strands stick out like tentacles from the DNA’s double helix, as a news release from Caltech . The DNA molecules collide in the water and bind together, producing and releasing offspring molecules. These act as the signals, like electrons in a traditional chip, and they travel among the DNA “gates,” connecting the circuit.
Pairs of gates can create and-or logic based on the output molecules observed, as Ars Technica explains it. (Check out for a more thorough explanation of how this works.)
The researchers, led by postdoctoral researcher Lulu Qian, can encode whatever DNA sequence they want, so they have full control over how the DNA strands interact.
Their largest computer was a 74-molecule, four-bit circuit that could compute the square root of any number up to 15, rounding down the answer to the nearest whole number. To get the answer, the researchers would monitor the concentration of output molecules in the test tube, using fluorescent tagging.
The process takes a long time, but speed is not the point — using this method, scientists could eventually engineer biochemical pathways that are capable of making decisions. This type of control over chemical reactions could be useful for anything from pharmaceuticals to industrial processes. Imagine DNA-based computer chips embedded in your skin, releasing drugs when the time is right, or a DNA computer that can study the concentration of certain molecules in a blood sample and quickly diagnose a disease.
The circuit can be scaled up to larger DNA computers, the researchers say. They can also be customized by adjusting the types of DNA used or reconfiguring the circuit.
“We want to make better and better biochemical circuits that can do more sophisticated tasks, driving molecular devices to act on their environment,” Qian said in a news release. The computer was described in a paper in today's issue of the journal Science.
[, ]
Hydrocarbons Could Form Deep In the Earth From Methane, Not Animal Remains
Study lends credence to abiogenic petroleum theory, which means there may be more oil in our future than we thought
Scientists at Lawrence Livermore National Laboratory used supercomputers to simulate what would happen to carbon and hydrogen atoms buried 40 to 95 miles beneath the Earth’s crust, where they would be subjected to prodigious pressures and temperatures.
They found at temperatures greater than 2,240 degrees F and pressures 50,000 times greater than those at the Earth’s surface, methane molecules can fuse to form hydrocarbons with multiple carbon atoms. Interactions with metal or carbon sped up the fusion process, the researchers said. These conditions are present about 70 miles down, according to an LLNL .
Methane, CH4, has one carbon and four hydrogen atoms; high hydrocarbons, like propane and butane, have more carbon atoms.
About 99 percent of all the hydrocarbons in oil and natural gas are derived from the compressed, heated remains of ancient living organisms like zooplankton and algae. These critters were buried under layers of sediments five to 10 miles beneath the surface of the Earth.
In the 19th and 20th centuries, some scientists believed hydrocarbons could form from abiogenic (non-biological) processes, too. The existence of methane on several solar system bodies shows hydrocarbons can exist without organic ingredients. But the theory , in part because no one ever found any abiogenic oil deposits.
The LLNL researchers don’t claim to know where such deposits would be, nor did they examine whether or how such deep deposits could ever migrate higher into the mantle where they could be retrieved. But the researchers say abiogenic hydrocarbons are technically possible in some settings like rifts or subduction zones, according to Giulia Galli, a professor at UC-Davis and senior author on the study, which appears in the Proceedings of the National Academy of Sciences.
“We don't say that higher hydrocarbons actually occur under the realistic 'dirty' Earth mantle conditions, but we say that the pressures and temperatures alone are right for it to happen,” she said.
[]
Using Muons as a Disguise, Chemists Fool Helium Into Thinking It’s Hydrogen
The quantum trick helps illustrate how atomic mass can affect chemical reactions
The trickery involves a particle accelerator, a heavy subatomic particle and some knowledge of quantum mechanics.
Donald Fleming of the University of British Columbia in Vancouver and his colleagues took muons produced at Canada’s TRIUMF particle accelerator, and of helium, molecular hydrogen (two hydrogen atoms) and ammonia. Positive muons resulted in muonium, a light version of hydrogen. Negative muons resulted in a heavy version of hydrogen, which has the nucleus of helium but behaves chemically like hydrogen. The latter effect has to do with fooling the electrons.
In the heavy version, the helium atoms captured the muons, which are much heavier than electrons. The negatively charged particles orbited very close to the helium atoms’ nuclei, where they effectively canceled out one of the protons. The other electron is thereby tricked into seeing a nucleus with just one positively charged particle, just like a hydrogen atom. But the nucleus is really 4.1 times heavier than normal. The light and heavy versions of hydrogen differ in size by a factor of 36, according to Fleming’s study, published Friday in the journal Science.
This is useful for studying the quantum effects at work during chemical reactions, according to the study. A single hydrogen atom can form molecular hydrogen by stripping away one of the atoms from a pre-existing H2 hydrogen molecule. This is accomplished at high energies, or through quantum tunneling, whereby an atomic particle doesn’t have to overcome the kinetic energy barrier that keeps it in its place.
Different atomic energies result in different chemical reaction rates, and Fleming et. al wanted to test this with the light muonium and heavy hydrogen. As they expected, the chemical reaction with the disguised helium was the slowest, as . The normal hydrogen's reaction was faster, followed by the light hydrogen. The rates perfectly matched predictions from quantum mechanical calculations led by Fleming's teammate Donald Truhlar of the University of Minnesota in Minneapolis.
The proof-of-theory confirms scientists' ability to predict the energies involved in chemical reactions, and could be useful in studying quantum effects.
[via ]
Can Our DNA Electromagnetically ‘Teleport’ Itself? One Researcher Thinks So
The full details of Montagnier’s experiments are not yet known, as his paper has not yet been accepted for publication. But he and his research partners have made a summary of his findings available. Essentially, they took two test tubes – one containing a fragment of DNA about 100 bases long, another containing pure water – and isolated them in a chamber that muted the earth’s natural electromagnetic field to keep it from muddying the results. The test tubes were housed within a copper coil emanating a weak electromagnetic field.
Several hours later, the contents of both test tubes were put through polymerase chain reactions to identify any remnants of DNA – a process that subjected the contents to enzymes that would make copies of any DNA fragments they found. According to Montagnier, the DNA was recovered from both tubes even though the second should have only contained water.
Montagnier and his team say this suggests DNA emits its own electromagnetic signals that imprint the DNA’s structure on other molecules (like water). Ostensibly this means DNA can project itself from one cell to the next, where copies could be made – something like quantum teleportation of genetic material, a notion that is spooky on multiple levels.
Naturally, there is plenty of skepticism to go around regarding these findings, ranging from outright dismissal to measured doubt. Indeed, it’s a pretty radical notion: DNA replicating itself through “ghost imprints” rather than the usual cellular processes. More details will emerge when the paper is published in a peer-reviewed journal, as it is likely to be. The findings will then have to be repeated in multiple independent studies to be considered valid, something that will take some time. In the meantime, expect these findings to draw equal parts intrigue and skeptical scrutiny.
[ via ]