Author Archives: flixt

A peice of history: the oldest known material on Earth

In Australia, on a sheep ranch just 600 Kilometers of Perth, a group of Scientists have just found the oldest known material on Earth.  The zircon crystal is extremely tiny, appearing as a single isolated grain. John Valley, a University of Wisconsin geoscience professor who led the research, used a dating technique called atom probe tomography to accurately date the crystal to an age of 4.4 billion years.

Zircon Crystal (Reuters)

Jack Hills, the region where the crystal was found (earthobservatory.nasa.gov)

In the past, the standard technique for dating materials  was a method called uranium-lead dating.  This method used the radioactive decay of uranium into lead, which one could then use to determine a materials age using half-lives. This would proved extremely useful for zircon dating as their crystalline formation tends to accumulate uranium.

However, some skeptics have argued against the accuracy of the method, as uranium and lead can be known to move around or even escape the zircon crystals through radiation damage. “If there’s a process by where lead can move from one part of the crystal to another place, then the place where lead is concentrated will have an older apparent age and the place from where it moves will have a younger apparent age” Valley said.

Timeline of the history of Earth. For perspective the formation of the earth was at 4.5 billion years while the Jack Hills Zircon was determined to be 4.4 billion years old. (Sydney Morning Herald)

In an attempt to end the debate, John Valley and his group determined the age of the zircon crystals through another technique. The technique, atom probe tomography, is a material analysis technique that gives extensive information about a material such as chemical composition with extreme accuracy.

By using atom probe tomography, the group of researchers managed to examine areas of the crystal with a length as small as 10 nm. At such distances, the effects of uranium-lead movement would be negligible.  As a result of their efforts, Valley and his group have confirmed that the zircon crystal was indeed 4.4 billion years old, hopefully quelling some of the argument.

Link to the Paper:

http://www.nature.com/ngeo/journal/v7/n3/full/ngeo2075.html

 

Felix Tang

Pressure Cooking to Sustainability

If you’re a technology enthusiast, then you’ve certainly noticed the increase of interest towards new technology emphasizing on the use renewable energy and alternative fuel sources.  One such source is Algae, which researchers have managed to use to produce crude oil, a process which normally takes a million years naturally but achievable within minutes in a lab!

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Researchers at the Pacific Northwest National Laboratory have recently published a new study detailing their new process of creating crude oil from a slurry of algae. The new process consists of pouring a mixture of water and algae into a reactor, which is essentially a giant pressure cooker extracting the oil from the algal lipids to produce crude oil in less than an hour. Byproducts of this process include a mixture of water and phosphorus which can be recycled to produce more algae. Previous attempts at producing crude oil from algae required species containing high lipid concentrations and drying them in order to extract the oils within. This process pioneered in the 1970’s was not popular due to its complexity and difficulty to produce.   The new process presents a much more efficient means of procuring  the sought after resource as it decreases the need for additional resources and time.

(source: flickr commons)

So why is the research on algal bio-fuel so exciting that it has even caught the eyes of mainstream media? Well, because of its ease of production, and potential as a source of renewable energy. The production of Algae, or Algaeculture is a growing field within the study of renewable energy. Algae as a species can grow almost anywhere and does not require fertile land to grow; Common algae species can contain up to 50 percent of oil and can be grown within a tank of water. This is efficient as Algae do not require much land to be grown and only require a source of light. Growing Algae can also be Eco-friendly as they are known to capture carbon dioxide and produce oxygen.

Algae Photobioreactor (Source: Wikipedia Commons)

As the technology towards better renewable energy improves we may be able to see an increase in use and production of bio-fuel from algae. Once it is economical to do so, it is predicted that an area the size of new mexico can provide for the entirety of current U.S. petroleum consumption and unlike other potential bio-fuel sources like corn, it won’t need to occupy any fertile land at all!

– Felix Tang –