Category: Physics

Fresh questions surrounding Rusi Taleyarkhan’s work on bubble fusion, are raised today in an exclusive news report online in the journal Nature.

Purdue University nuclear engineer Taleyarkhan, came to prominence in
2002 when he claimed to have achieved table-top nuclear fusion in collapsing bubbles. If the effect were real, and could be harnessed, it could provide us with effectively unlimited energy at very little cost.

However, several of Taleyarkhan’s colleagues at Purdue have revealed to the journal that their confidence in his work and results has been seriously dented since he arrived in their department in 2004. Faculty members Lefteri Tsoukalas and Tatjana Jevremovic, along with several others who do not wish to be named, say that since Taleyarkhan began working at Purdue, he has removed the equipment with which they were trying to replicate his work, claimed as ‘positive’, experimental runs for which they never saw the raw data, and opposed the publication of their own negative results.

Moreover, UCLA’s Brian Naranjo is submitting a paper to Physical Review Letters that provides an analysis of Taleyarkhan’s recently published data. The conclusions strongly suggests that Taleyarkhan did not detect fusion, but a standard lab source of radioactivity. This latest episode seems certain to burst the bubble, but Nature leaves a caveat in their press release on this subject:

“Bubble fusion is theoretically possible,” the journal says, “but do these latest findings spell the end for this particular line of enquiry?”

Well, perhaps it isn’t their place to actual wield the needle, but on the basis of Naranjo’s study it certainly looks like the bubble has gone pear-shaped to say the least.

A combination of physics and chemistry helped researchers identify the two “new” chemical elements – 113 and 115. The elemental discoveries took place at the Russian nuclear research centre (JNIR) in Dubna in 2003, but ongoing experiments are underway to provide additional evidence.

Heavy elements decay by emitting alpha particles (helium nucleus). American, Russian and Swiss scientists used this decay to prove the existence of elements 115 and its alpha decay product 113. In order to synthesize atoms of element 115 a rotating target disc of americium was bombarded with a calcium beam. Fusion between Americium and calcium produced a detectable quantity of 115 atoms.

However the formation of the atoms was not enough to prove the element’s existence as its atoms only exist for a tenth of a second and are difficult to detect. The radiochemical experiments proved much more successful yielding a provable five times as many atoms.

As expected, element 115 emits an alpha particle to decay to element 113. Four subsequent emissions produce dubnium, element 105. A copper plate was held behind the rotating americium disc to collect all element 115 atoms emitted from the target. The researchers then used liquid chromatography techniques to observe fifteen atoms of dubnium.

The decay pattern of these atoms supported the physics experiments, thus proving the earlier discovery of element 115 and its offspring element 113. All elements below atomic number 113 are already known.

Quite astonishingly a press release today from the Paul Scherrer Institute in Switzerland seemed to imply that these elemental discoveries were recent and that somehow they were down to the PSI. This is, not the case. Dozens of researchers were involved in the discovery, which was reported on Sciencebase and elsewhere in September 2003.

Take a look here for a timeline of elemental discoveries

As Einstein Year draws to a close, CERN celebrates the big man with an epic 12-hour live webcast looking at relativity and beyond. Sciencebase contributor Michael Marshall is helping with the publicity and tells us the webcast offers a unique chance to chat with scientists and find out how a century-old bright idea has changed the world in which we live.

1st December: 12h00-00h00 Central Eur Time

In a guest sciencebase editorial, Dean L Sinclair suggests that neutrons may not exist in the nucleus and goes on to explain how nuclear structure might be explained by an altogether different model that sidesteps problematic forces that have to be invoked by the proton-neutron model of the atomic nucleus. Tell us what you think…

Dr Myriam Sarachik (of City College in New York City) escaped the Holocaust from Belgium to become a prominent physicist and educator.

She will be honoured on 28th February in Paris as the recipient of the L’Oreal-UNESCO’s Women in Science Prize as a laureate.

The selection of five laureates representing five regions of the world, by a jury of world class scientists that includes some Nobel Prize winners, and the award of 15 Fellowships to aspiring young women scientists, has attracted the attention of the scientific community. The prize which has now recognized 91 women from 45 different countries has enabled young women to continue their education and scientific research as they enter the field and has promoted the groundbreaking research of senior women scientists.

Sarachik’s career in experimental condensed matter physics has included work on superconductivity, disordered metallic alloys, metal-insulator transitions, hopping transport in solids, and the behavior of molecular magnets. In particular, she has made seminal contributions to Kondo physics, metal-insulator transitions, and quantum spin dynamics. In her low temperature laboratory, she and her team are pursuing the study of condensed matter properties at low temperatures, with particular focus on two areas: molecular nano-magnets and the novel behavior of two-dimensional electron systems.