Radiocarbon dating (sometimes simply known as carbon dating) is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 (C) to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" (BP), "Present" being defined as 1950. Such raw ages can be calibrated to give calendar dates. One of the most frequent uses of radiocarbon dating is to estimate the age of organic remains from archaeological sites. When plants fix atmospheric carbon dioxide (CO2) into organic material during photosynthesis they incorporate a quantity of C that approximately matches the level of this isotope in the atmosphere (a small difference occurs because of isotope fractionation, but this is corrected after laboratory analysis). After plants die or they are consumed by other organisms (for example, by humans or other animals) the C fraction of this organic material declines at a fixed exponential rate due to the radioactive decay of C. Comparing the remaining C fraction of a sample to that expected from atmospheric C allows the age of the sample to be
Aligned carbon nanotube / graphene sandwiches
By in situ nitrogen doping and structural hybridization of carbon nanotubes (CNTs) and graphene via a two-step chemical vapor deposition (CVD), scientists have fabricated nitrogen-doped aligned carbon nanotube/graphene (N-ACNT/G) ...
Distinctive body type aids long life and predation
Jellyfish (Cnidarian medusa) have unique body plans that violate a universal law of biology and facilitate their longevity and their propensity to form blooms, according to an international study involving UWA scientists.
New NIST tests explore safety of nanotubes in modern plastics over time
(Phys.org) —Who cares about old plastic? Researchers at the National Institute of Standards and Technology (NIST) do, so that you won't have to years down the road, when today's plastic concoctions start to break down and ...
Turning plastic bags into high-tech materials
University of Adelaide researchers have developed a process for turning waste plastic bags into a high-tech nanomaterial.
Research shows graphene nanopores can be controlled
(Phys.org)—Engineers at the University of Texas at Dallas have used advanced techniques to make the material graphene small enough to read DNA.
New technique controls graphite to graphene transition
(Phys.org) -- University of Arkansas physicists have found a way to systematically study and control the transition of graphite, the lead found in pencils, to graphene, one of the strongest, lightest and most ...
Researchers studying nanotube toxicity develop method for finding them in soils
(Phys.org)—Carbon nanotubes (CNTs) could pave the way for remarkable technology, from improved computer chips, flexible computer screens or body armor, to health applications such as bone healing and cancer treatments.
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