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
Carbon nanostructures grow under extreme particle bombardment
(Phys.org) —Nanostructures, such as graphene and carbon nanotubes, can develop under far extremer plasma conditions than was previously thought. Plasmas (hot, charged gases) are already widely used to produce ...
Defining the graphene family tree
There has been an intense research interest in all two-dimensional (2D) forms of carbon since Geim and Novoselov's discovery of graphene in 2004. But as the number of such publications rise, so does the ...
'Waviness' explains why carbon nanotube forests have low stiffness
A new study has found that "waviness" in forests of vertically-aligned carbon nanotubes dramatically reduces their stiffness, answering a long-standing question surrounding the tiny structures.
With carbon nanotubes, a path to flexible, low-cost sensors
Researchers at the Technische Universitaet Muenchen (TUM) are showing the way toward low-cost, industrial-scale manufacturing of a new family of electronic devices. A leading example is a gas sensor that ...
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.
Accidental nanoparticle discovery could hail revolution in manufacturing
A nanoparticle shaped like a spiky ball, with magnetic properties, has been uncovered in a new method of synthesising carbon nanotubes by physicists at Queen Mary University of London and the University of ...
Graphene provides efficient electronics cooling
A layer of graphene can reduce the working temperature in hotspots inside a processor by up to 25 percent – which can significantly extend the working life of computers and other electronics. An international ...
Graphene layers dramatically reduce wear and friction on sliding steel surfaces
(Phys.org) —Sometimes, all it takes is an extremely small amount of material to make a big difference. Scientists at Argonne National Laboratory have recently discovered that they could substitute one-atom-thick ...
Study finds fungi, not plant matter, responsible for most carbon sequestration in northern forests
Microbes surviving deep inside oceanic crust
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.
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.
Graphene films—highly resistant to damage—could protect metals in harsh environments
(Phys.org)—A coating so thin it's invisible to the human eye has been shown to make copper nearly 100 times more resistant to corrosion, creating tremendous potential for metal protection even in harsh ...
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 ...