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.
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 G and R functions. 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