Scientific debate around Cheonan findings heats up
:Two experts say the explosive aluminum oxide discovered was really Gibbsite, a clay substance
By Lee Yong-inn
Posted on : Jul.2,2010 12:31 KST
The “scientific debate” surrounding the results of the joint civilian-military investigation team has heated up, as refutations and counter points have emerged from several scientists who have raised issues with the findings. In particular, scientists have voiced the opinion that the results of analysis of explosive residue found on the ship, raised as one of the pieces of “decisive evidence” of a torpedo attack, is similar to a substance that appears in simple clay.
University of Virginia Physics Professor Lee Seung-heon and Dr. Yang Panseok, head of analysis at the University of Manitoba’s department of geological sciences, said in a report recently sent to Hankyoreh 21 that the energy spectroscopy graph announced on May 20 as an explosive substance was not droplets of aluminum oxide, an explosive substance, but Gibbsite, a clay substance that naturally occurs due to weathering. Gibbsite could come from sediment soil from the seas in front of Baengnyeong Island, and it is commonly extracted in its natural state and used as fire-retardant material in vessels like the Cheonan.
In analyzing an energy spectroscopy graph, it is possible to identify a substance though the ratio of its elements. The joint investigation team determined the substance was aluminum oxide, with an aluminum-oxygen ratio of 0.92 for the residue found on the Cheonan hull and 0.9 on the fragments of the torpedo. The two scientists, however, said the results of simulations at the U.S. National Institute of Standards and Technology (NIST) resulted in an aluminum-oxygen ratio of 0.23 for aluminum oxide, and that the result presented by the investigation team was closer to Gibbsite at 0.85.
In response to criticism that the substance had too much oxygen for aluminum, the investigation team said in a meeting with representatives of the press on June 29 that the sample of the substance absorbed into the hull was about 40 percent water, which includes oxygen.
Professor Lee, a joint researcher, said that energy spectroscopy tests are performed in a vacuum, so there could be no moisture in the test. He said the moisture the investigation team referred to was just the hydrogen and oxygen that exists in Gibbsite, mistakenly identified by the team.
A senior-level researcher with a civilian research facility that handles sample analysis said Thursday that a spectroscopy test measures the frequency of electrons as they collide and are emitted after a sample has been zapped with an electron gun. He explained that only if the sample is in a vacuum could electrons reach it. The researcher said the sample is dried beforehand, and even if it is not, all the moisture would leave during the process of creating a vacuum.
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Requested Security Council Cheonan measures weaken considerably
: Instead of sanctions against North Korea, the proposed statement now denounces “those responsible”
By Kwon Tae-ho
Posted on : Jul.2,2010 12:27 KST
'Contrary to the Lee Myung-bak administration’s initial expectations, the U.N. Security Council measures on the Cheonan sinking currently being pursued by the administration are known to be at a rather muted level.'
'In the early stages, the Lee Myung-bak administration primarily used the phrase “a resolution for sanctions against North Korea” in referring to UNSC measures in response to the Cheonan sinking. Currently, however, it is having a difficult time inserting a passage in the president’s statement specifying that North Korea bears responsibility for the sinking of the Cheonan. The government official said that the draft adopted by the UNSC would be at the level of the statement from the G-8 summit held in Canada.'
'However, due to objections from Russia, the G-8 summit did not specify that “those responsible” referred to “North Korea.” The UNSC, however, includes China, which is not part of the G-8 summit. In terms of scope, the UNSC draft is expected to fall short of the G-8 summit statement.'
'Meanwhile, North Korea sent a letter to the UNSC on Tuesday stating the need for a joint North Korean-South Korean investigation to determine the facts of the Cheonan’s sinking. While this was not a significant departure from its previous request to send a review team, it does indicate a relative step forward. The U.S. expressed its opposition, saying that no further investigation of the Cheonan sinking was necessary.'