A hydrophobic oil absorbing marshmallow


via +Cheryl Hurkett is this video demon­strat­ing a marshmallow-like mac­ro­por­ous gel that could be used for sep­ar­at­ing oil and water. Like the accom­pa­ny­ing press release says, this is obvi­ously use­ful for mar­ine oil spills, but there are many more applications.


#twt   #chem­istry  

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Rehydroxylation Dating


I referred to this news story as being poten­tially the archae­olo­gical story of the dec­ade on twit­ter. Potentially is a good weasel word, but if Rehydroxylation Dating can be inde­pend­ently veri­fied then it could be a more import­ant form of dat­ing than radiocar­bon dat­ing. The reason it’s so excit­ing is that this method will allow archae­olo­gists to date pot­tery. A couple of warn­ings before I start. I am not a mater­i­als sci­ent­ist so it’s pos­sible that if some­thing seems odd that’s me mess­ing up the descrip­tion. The other is I am not on the research team — I’ve merely emailed some questions.

Saxon Pottery
Late Saxon Pottery, but how late? Photo (cc) Wessex Archaeology.

Pottery and other ceram­ics make up most of the data that you’ll find on an archae­olo­gical site. Unfortunately there hasn’t been an easy way to dir­ectly date it. The most com­mon way is by style. Pot types and tech­no­logy come into and out of fash­ion. Terra sigil­lata, Samian Ware, is par­tic­u­larly good for this as styles turned over rap­idly. However, that no help if all you have is a frag­ment of cruddy Iron Age pot. Another method would be by asso­ci­ation with organic mater­ial. If you find some grain in the same strata, you can date that and by asso­ci­ation when mater­ial was depos­ited in that strata. There are some prob­lems. Radiocarbon will give you a range of dates rather than one date. This range can be quite wide and it’s prone to con­tam­in­a­tion. What would be use­ful would be a way of dat­ing ceram­ics dir­ectly. You can do this with ther­mo­lu­mines­ence, which uses nat­ural radio­activ­ity to give a date, but it’s com­plex and dif­fi­cult so it’s rarely used. A team mainly based at Manchester University have announced that they can date ceramic mater­i­als, such as pot­tery, tile and brick, through a pro­cess called rehyd­roxyla­tion. It seems to be sim­pler than both ther­mo­lu­mines­ence and radiocar­bon dat­ing and much harder to acci­dent­ally con­tam­in­ate. There are some impress­ive addi­tional uses for the method which could make a lot of excav­ated mater­ial a lot more use­ful.
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