An important part of the Fermilab’s Recycler Electron Cooling (REC) project [1] is a recirculation test which is performed using a 5-MV electrostatic accelerator, a Pelletron, with two tubes and a simplified beam line with one 180-degree bend. The main goal of the test is to demonstrate stable operation of a 4.4-MeV, 0.5-A DC electron beam. The paper describes the set-up and the early experimen...

In river meandering, when flow passes through a bend, reduction of flow velocity and rising hydrostatic pressure cause super elevation phenomena at outer side and reduction of water surface at inner-side of the bend. A helical motion results, causing erosion of the outer side of the bend. Installation of submerged vanes on the stream bed can reduce erosion of the outer bank significantly. In th...

A numerical study, using the volume-of-fluid method (VOF), has been made of core-annular flow in a curved pipe. We investigated two cases: core-annular flow in a 90◦ bend and in a 180◦ return bend. To verify our numerical method we first compared our results for a singlephase flow in a 90◦ bend with numerical results and experimental data given in the literature. The agreement was good. Thereaf...

Type II DNA topoisomerases actively reduce the fractions of knotted and catenated circular DNA below thermodynamic equilibrium values. To explain this surprising finding, we designed a model in which topoisomerases introduce a sharp bend in DNA. Because the enzymes have a specific orientation relative to the bend, they act like Maxwell's demon, providing unidirectional strand passage. Quantitat...

A 68-year old male with ischaemic cardiomyopathy who underwent HeartMate II implantation complained of chest discomfort 4 months after the operation. Computed tomography images clearly demonstrated a disconnected outflow graft bend relief (Fig. 1). During reoperation, the bend relief was indeed found to be disconnected and the outflow graft was severely abraded by the sharp metal end of the ben...