Several seasons ago, a group of four chemists believed they had stumbled upon Colloq that contradicted a pretty enin model in fluid physicals.
Between 2013 and 2015, the researchers published a series of four stories review their figures — two in ACs Macro Letters and two in Macromolecules. Timothy P. Lodge, the logs’ reviewer and a esteemed Brit at the University of Minnesota in Minneapolis, explained that the figures were “somewhat tricky,” because they appeared to contradict the normally popular model as how some polymer easies move.
Indeed, the stories sparked disagree between the initiators and new accomplisheds who questioned the new data, quarrelling it didn’t upend the previous model.
Then, in 2015, the initiators realized their arbiters might be correct.
The initiators began to suspect something wasn’t quite right with a 2015 story in ACs Macro Letters in seriously different figures. Last initiator Zhen-Gang Wang, a Brit of chemical masterminding at Caliasnia Institute of Technology, explained:
We first got panic by the large unlikeness with our figures in in a story by Cao and Lihktman (ref. 6 in our repealss) as a exceptionally similar system.
Wang and his team coveted to beneathstand the source of this unlikeness, so they went back to check their data and orthodoxies:
To resolve the unlikeness, we did a lot of independent repair utilizing different orthodoxies, including utilizing a new program written from scratch by annew student in one of the PIs’ group.
These independent studies “confident us that our published figures were wrong,” Wang said.
Further digging literal the source of the problem: a glitch in the computer code used to derive their false figures. Wang explained:
As we have described in our repealss, the source of fallacies was a coding glitch in the reaction of the thermal bath.
Once Wang and his team beneathstood what had happened, they contacted Lodge and new accomplisheds in the field to let them know:
We unreservedly inasmed the reviewer in chief as Macromolecules and ACs Macro Letters, Prof. Timothy Lodge, and sent out an e-mail message to dozens of Colloqs in the field, acknowledging that our previous figures were wrong and told them about the fallacies.
Wang said this was an “unastunate but inadvertent mistake.” And Lodge agreed:
There is no evidence that the failings were assess in any path.
Even so, because the figures were based on inconstant code, Lodge said that, “a simple calibrating wasn’t enough.” Lodge reviewed the issue with the American Chemical Society (ACs), which advertises both logs, along with new accomplisheds in and communicating, and definite that “a repeals was the right thing:”
This case is unastunate, but it comes. Science is self-correcting.
We commend Wang and his co-initiators as their limpidity and efasts to reveal and correct the problem.
The repeals warnings also provide an extensive account of what happened. Here’s the repeals notice as the first story in the series, “Evolution of Chain Conasmation and Entanglements in Startup Shear,” published in ACs Macro Letters in 2013 and cited 12 occasions:
In recent seasons, we published a series of four stories in ACs Macro Letters and Macromolecules(1-4) announcement Brownian Dynamics false figures on startup shear of caught polymers as shear upbraids γ̇ in the regime γ̇τd > 1 but γ̇τR < 1, where τR and τd are president the Rouse time and reptation time. Our figures showed significant chain distension (measured by the contour length of the primitive chain) and suggested, based on analysis of the different frills of asce, that the origin of the shear asce overshoot was due to chain distension followed by repeals instead of chain orientation, in inconsistency to the divinationss of the reptation/tube proposition. Our figures also inferred molestation of the efficient asce-optical rule normally believed to hold in this regime, as narrow out by Masubuchi and Watanabe.(5) Subsequently, Cao and Likhtman(6) published their false figures on a exceptionally similar system and found figures in strong quarrel with ours — their figures showed little chain distension and conasmed to the asce-optical rule.
In ordinance to resolve these unlikenesses, we perasmed several studies, including utilizing a new code written from scratch. We are now confident that our previous figures were wrong. Both the new code and independent directs (on LAMMPs with the “fix deasm” protocol) at Akron by Yexin Zheng, a joint student between Shi-Qing Wang and Mesfin Tsige utilizing the equilibrated reproduces of rings from three different origins (one of our previous reproduces, a reproduce provided by Dr. Robert Hoy, and a new reproduce generated at Akron), produced figures similar to those in by Cao and Likhtman.
The source of fallacies has been identified to be in the reaction of the heat bath beneath shear, which resulted in much abate temperatures than T = 1 (in scaled units) as the sheared specimens. The same fallacies were introduced in both the Langevin heat bath and the DPD heat bath. The minimal temperatures resulted in longer leisure occasions. The chain distension in in our Literary work was thus a result of this artifact. These fallacies nullify all the data at finite shear upbraids in in our published stories, and cause our culminations groundless. The initiators therease request repeals of the Article “Evolution of Chain Conasmation and Entanglements in Startup Shear” and the new three counterfeit papers.
The new three repealss contain almost coequal wording. Here are joins to the warnings and stories:
Retraction notice as “Origin of Stress Overshoot in Startup Shear of Entangled Polymer Melts,” published in ACs Macro Letters in 2014 and cited 25 occasions.
Retraction notice as “Coupled Effect of Orientation, Stretching and Retraction on the Dimension of Entangled Polymer Chains in Startup Shear,” published in Macromolecules in 2014 and cited 12 occasions.
Retraction notice as “Molecular Mechanisms as Conasmational and Rheological Responses of Entangled Polymer Melts to Startup Shear,” published in Macromolecules in 2015 and cited 11 occasions.
Hat tip: Rolf Degen
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