The process of retraction in entangled linear chains after a fast nonlinear stretch was detected from time-resolved but quenched small angle neutron scattering (SANS) experiments on long, well-entangled polyisoprene chains. The statically obtained SANS data cover the relevant time regime for retraction, and they provide a direct, microscopic verification of this nonlinear process as predicted b...

turbulent mixed convection of a nanofluid (water/al2o3, φ=.02) has been studied numerically. two-phase mixture model has been used to investigate the effects of nanoparticles mean diameter on the flow parameters. nanoparticles distribution at the tube cross section shows that the particles are uniformly dispersed. the non-uniformity of the particles distribution occurs in the case of large nano...

Concentric tube manipulators have the diameter of needles and are consequently amenable to delivery into the human body through small ports in an endoscope. When this is done, the surgeon must manipulate both the endoscope and one or more concentric tube robots simultaneously. In this paper we explore a hand-held approach to this user interface challenge, in which the surgeon has direct physica...

in vascular plants, the soil solution is transported from the roots to the leaves through smalldiameter vessels found in the xylem; this transport not only allows the nutrient uptake but also the accumulation of heavy metals in their shoots. by analogy to this phenomenon, the present study aimed at the evaluation of heavy metals transport (pb, cr, as, cd, zn, ni and al) in ph 4 and ph 8 solutio...

in vascular plants, the soil solution is transported from the roots to the leaves through smalldiameter vessels found in the xylem; this transport not only allows the nutrient uptake but also the accumulation of heavy metals in their shoots. by analogy to this phenomenon, the present study aimed at the evaluation of heavy metals transport (pb, cr, as, cd, zn, ni and al) in ph 4 and ph 8 solutio...

A 78-year-old male with multiple previous abdominal operations presented to the emergency department (ED) with abdominal pain and vomiting. Computed tomography (CT) revealed a small bowel obstruction. The emergency physician ordered a nasogastric tube and the nurse placed a 14 French catheter. The nurse encountered resistance upon advancement to just before the target length based on her initia...

Application of nanofluid and coiled tubes are two passive methods for increasing the heat transfer. In the present study, the turbulent flows of water and nanofluid in coiled tubes heat exchanger were numerically studied. CuO-water nanofluid containing 1 vol% copper oxide nanoparticles was used and single-phase approach was considered for nanofluid flow. The effect of different geometrical para...

A graph that contains a spanning tree of diameter at most t clearly admits a tree t-spanner, since a tree t-spanner of a graph G is a sub tree of G such that the distance between pairs of vertices in the tree is at most t times their distance in G. In this paper, graphs that admit a tree t-spanner of diameter at most t + 1 are studied. For t equal to 1 or 2 the problem has been solved. For t = ...

In this paper, hydroforming process of bent tubes in T-shaped die is studied for pulsating and linear pressure paths by the finite element method. Forming Limit Diagrams (FLDs) and thickness distribution curves are used to investigate the effect of pulsating pressure on hydroforming process. In addition, the obtained numerical results are compared with experimental results of hydroforming of st...