Drag reduction has become a serious issue in recent years in terms of energy conservation and environmental protection. Among diverse approaches for drag reduction, superhydrophobic surfaces have been mainly researched due to their high drag reducing efficiency. However, due to limited lifetime of plastron (i.e., air pockets) on superhydrophobic surfaces in underwater, the instability of dewett...

Oxygen consumption (VO2) during surface swimming and total body drag were investigated in the North American mink, Mustela vision Schreber. Over the range of 0.13-0.70 ms-1, VO2 increased curvilinearly with speed for minks swimming against a current in a water flume. Similarly, body drag of a mink carcass increased non-linearly with speed and was described by the equation, Drag = 1.24 velocity....

This paper focusses on the prediction of one of the main mechanisms of acoustic attenuation, the dynamic drag impedance, of a bundle of fibres typical of lightweight fibrous porous materials. The methodology uses geometrical properties derived from microscopy, and is based on the assumption that the interaction between the shear stress fields of neighbouring fibres may be neglected in the predi...

In Taylor-Couette flow the total energy dissipation rate and therefore the drag can be determined by measuring the torque on the system. We do so for Reynolds numbers between Re=7 x 10(4) and Re=10(6) after having injected (i) small bubbles (R=1 mm) up to a volume concentration of alpha=5% and (ii) buoyant particles (rhop/rhol=0.14) of comparable volume concentration. In case (i) we observe a c...

Abstract We calculate the drag force on a heavy quark hit by a shock wave, thus generalizing the strongly coupled AdS/CFT heavy quark drag calculations to both hot and cold nuclear matter. The derivation employs the trailing string configuration, similar to that used in the literature for a quark moving through a thermal medium, though in the shock metric the string profile is described by a mu...

This paper describes an experiment to investigate if the addition of non-speech sounds to the drag and drop operation would increase usability. There are several problems with drag and drop that can result in the user not dropping a source icon over the target correctly. These occur because the source can visually obscure the target making it hard to see if the target is highlighted. Structured...

The diagrammatic linear response formalism for the Coulomb drag in two{layer systems is developed. This technique can be used to treat both elastic disorder and intralayer interaction eeects. In the absence of intralayer electron{electron correlations we reproduce earlier results, obtained using the kinetic equation and the memory{function formalism. In addition we calculate weak{localization c...

Enhancing the aerodynamic efficiency of commercial vehicles is gaining increasing importance as it helps to reduce both overall fuel consumption as well as emissions. This paper investigates the advantages offered by a novel fuel-saving device for such vehicles. This device uses a moving surface to impart additional kinetic energy to flow near the roof surface. The additional momentum in the fl...

It is a new challenge to provide priority-based delivery in low duty-cycled sensor networks where there are not always-awake communication paths and the wireless links are very time-varying and unreliable. In this paper, we propose a Dynamic Routing Algorithm for priority Guarantee(called DRAG) in low duty-cycled sensor networks. Both schemes of dynamic forwarding decision making and priority-b...

We show theoretically that the Coulomb drag rate between two parallel quasi-two-dimensional electron gases is substantially enhanced by the coupled acoustic and optic plasmon modes of the system at temperatures T ∼ 0.2TF (where TF is the Fermi temperature) for experimentally relevant parameters. The acoustic mode causes a sharp upturn in the scaled drag rate as a function of temperature at T ≈ ...