Last month, we brought you news of two retractions in math journals for duplicate publication and apparent guest authorship. Last week, we learned that the lead author of one of those papers, Amir Mahmood, has retracted another paper, this one in *Nonlinear Analysis: Real World Applications*.

According to the retraction notice, the paper was an “accidental duplication of an article that has already been published” in *Communications in Nonlinear Science and Numerical Simulation*.

The papers share two authors: Mahmood, of the department of mathematics at COMSATS Institute of Information Technology and the Abdus Salam School of Mathematical Sciences of GC University, both in Lahore, Pakistan; and N.A. Khan, of the University of Karachi’s math department. Khan was also on one of the two papers we wrote about last month, but not the one Mahmood co-authored. Those two papers’ shared author was M. Jamil.

Mahmood told Retraction Watch by email that the papers are not duplicates, and that the journal editors could not explain to him why they were.

Retraction Watch readers can be the judge. The abstract of the retracted paper:

In this paper, we have determined the exact starting solutions of velocity field and associated shear and normal stresses corresponding to the unsteady flow of a Maxwell fluid, due to torsional oscillations of two infinite coaxial circular cylinders by means of Laplace and Hankel transforms. The fluid is situated at rest in an annular region between the cylinders. Suddenly both cylinders start torsional sine oscillations around their common axis, with different angular frequencies of their oscillations. The starting solutions that have been obtained satisfy the governing equation of motion and all imposed initial and boundary conditions. Furthermore, these solutions, presented as a sum of steady-state and transient solutions, reduce to the similar solutions for Newtonian fluid as the limiting case. They describe the motion of the fluid for some time after its initiation. After that time, when the transients disappear, the unsteady solutions tend to the steady-state solutions which are periodic in time and independent of initial conditions. Finally, numerical results and concluding remarks are given.

The abstract of the original paper:

The velocity field and the associated shear stress corresponding to the torsional oscillatory flow of a generalized Maxwell fluid, between two infinite coaxial circular cylinders, are determined by means of the Laplace and Hankel transforms. Initially, the fluid and cylinders are at rest and after some time both cylinders suddenly begin to oscillate around their common axis with different angular frequencies of their velocities. The solutions that have been obtained are presented under integral and series forms in terms of generalized

GandRfunctions. Moreover, these solutions satisfy the governing differential equation and all imposed initial and boundary conditions. The respective solutions for the motion between the cylinders, when one of them is at rest, can be obtained from our general solutions. Furthermore, the corresponding solutions for the similar flow of ordinary Maxwell fluid are also obtained as limiting cases of our general solutions. At the end, flows corresponding to the ordinary Maxwell and generalized Maxwell fluids are shown and compared graphically by plotting velocity profiles at different values of time and some important results are remarked.

The journal’s three editors have yet to respond to requests for comment.

*Hat tip: Ivan Christov*

The link to the retraction does not work (already!).

I think it would be a good idea if the bibliographic

details of papers discussed on Retraction Watch,

especially retracted papers, were given (volume, date,

etc.).

I have the impression that publishers are trying to

make retractions hard to find. RW could combat this.

Thanks for flagging that, Douglas, we’ll see what we can find out about why that DOI is no longer working. Good point on bibliographic details; we always try to link to at least one version of retracted studies that will give those. But we’ll keep it in mind.

The link, along with a number of other DOIs, have been down recently, all related to the transfer of electronic content from our old Science Direct platform to the new SciVerse Science Direct. It’s just a minor technical problem that is expected to be resolved soon.

Prof. Arnold makes a very important point. In fact, at the bottom of the page for a “Withdrawn Article in Press”, it is stated that

“Withdrawn Articles in Press are only visible to users when following an external link, e.g., an end user following a PubMed or DOI link. Such Withdrawn Articles in Press are not searchable or otherwise available in ScienceDirect.”

So, no one can ever find that article again, unless he/she knew about it before it was withdrawn.