This work experimentally investigates the effect of vapour velocity during condensation of a ref rigerant on the outside of a single horizontal enhanced tube with particular reference to the fluid-dynamic mechanisms indu ced by vapour shear stress, surface tension and gravity on the condensate flow. More than 70 experimental runs were done in a transparent test section in order to directly o bs...

A numerical and experimental study is performed on transient natural convection in an insulated rectangular tank. The liquid is suddenly heated by a line source or cooled by a line sink being placed at the center of the free surface to initiate a thermocapillary force. Evaporation or condensation takes place on the free surface. A finite-difference technique is employed to numerically integrate...

We report a novel, scaleable and versatile method for large scale synthesis of tungsten trioxide nanowires and their arrays on a variety of substrates including amorphous quartz, fluorinated tin oxide, etc. The synthesis concept uses the chemical vapor transport of metal oxide vapor phase species onto substrates using air or oxygen flow over hot-filament sources. The hot-filaments were designed...

In recent years, experimental data were published which point to the possibility of the existence of superfluidity in solid helium. To investigate this phenomenon theoretically we employ a hierarchy of equations for reduced density matrices which describes a quantum system that is in thermodynamic equilibrium below the Bose-Einstein condensation point, the hierarchy being obtained earlier by th...

Periodically switching between evaporation and condensation, or "humidity cycling", has potential for controlling the film shape that results from volatile droplets containing a nonvolatile material. It does not require adaptation of material properties nor the introduction of an external field to achieve a change in film shape. It was shown experimentally by Doi and coworkers [Kajiya et al. La...

The paper expresses a mathematical model of homogeneous gas motion with respect to formation processes and the growth condensation nuclei. Since condensed particles are small, research is carried out single velocity model. results obtained have shown that application cylindrical tube leads nonlinear flow effects. responds to: geometrical exposure related transition from conical diverging nozzle

The helicity condensation model has been proposed by Antiochos (2013) to explain the observed smoothness of coronal loops and the observed buildup of magnetic shear at filament channels. The basic hypothesis of the model is that magnetic reconnection in the corona causes the magnetic stress injected by photospheric motions to collect only at those special locations where prominences form. In th...

We perform a quasinormal mode analysis of black-hole configurations in Bose-Einstein condensates (BECs). In this analysis we use the full Bogoliubov dispersion relation, not just the hydrodynamic or geometric approximation. We restrict our attention to one-dimensional flows in BECs with steplike discontinuities. For this case we show that in the hydrodynamic approximation quasinormal modes do n...

Potential condensed clouds of gas in the Galactic halo are examined in the context of the recent models of cooling, fragmenting clouds building up the baryonic mass of the Galaxy. 582 high-velocity clouds (HVCs) are defined as the potential infalling, condensed clouds and the sample’s spatial and velocity distribution are presented. With the majority of the hydrogen in the clouds ionized (∼ 85%...

A review of recent experimental studies of turbulence suppression by mean flows in quasi-two-dimensional fluids is presented. Large-scale mean flows develop during spectral condensation of 2D turbulence as a result of the inverse energy cascade in spatially bounded flow. The spectral energy which is accumulated at the largest scale supports the mean flow which in turn affects turbulence. We sho...