Hot tips are used either for characterizing nanostructures by using Scanning Thermal Microscopes or for local heating to assist data writing. The tip-sample thermal interaction involves conduction at solid-solid contact as well as conduction through the ambient gas and through the water meniscus. We analyze those three heat transfer modes with experimental data and modeling. We conclude that th...

effect of scale on the hydrodynamics of gas-solid fluidized beds was investigated in two fluidized beds of 152 mm and 78 mm in diameter.  air at room temperature was used as the fluidizing gas in the bed of sand particles. the radioactive particle tracking (rpt) technique was employed to obtain the instantaneous positions of the particles at every 20 ms of the experiments. these data were used ...

A simulation scheme is proposed for flowfield and radiation analysis of solid rocket exhaust plumes at high altitude. Several recently developed numerical procedures are used to determine properties of the gas and condensed phase Al2O3 particles, and spectrally resolved plume radiation calculations are performed using a Monte Carlo ray trace model. Simulations are run for a representative plume...

We numerically investigate the interaction between gas-particles flows and shock waves that form during the explosive decompression of underexpanded jets. Simulations are carried out using a validated second-order accurate numerical model for multiphase flows. We quantify theoretically the expected non-equilibrium effects between the gas and the solid phase in terms of the ratio between the par...

Diatomic Hypothesis and Calculation of Condensation Force Author: Zeljko Prebeg Lermanova 12a, 10000 Zagreb, Croatia [email protected] Abstract: The concept of a molecular pair as the base of organization for matter successfully describes the polymerization phenomena. For this reason, a diatomic hypothesis is hereto postulated. According to the diatomic hypothesis, matter is organized in ...

computational fluid dynamics (cfd) simulations of gas-solid flow through a positive low-pressure pneumatic conveyor were performed using eulerian-eulerian framework. pressure drop in pneumatic conveying pipelines, creation and destruction of plugs along the horizontal and vertical pipes, effect of 90° elbows and u-bends on cross-section concentrations, and rope formation and dispersion were num...

Two-interconnected fluidized bed systems are widely used in various processes such as Fisher-Tropsch, hot gas desulfurization, CO2 capture-regeneration with dry sorbent, chemical-looping combustion, sorption enhanced steam methane reforming, chemical-looping hydrogen generation system, and so on. However, most of two-interconnected fluidized beds systems require riser and/or pneumatic transport...

In this work, we develop a self-consistent physical model of bubbles in a gas solid two-phase 1 flow. Using the Peng-Robonson state equation and a detailed specific heat ratio equation of bubbles, 2 we obtain the kinetic equations of the bubbles on the basis of the Ergun equation, thermodynamic 3 equations, and kinetic equations. It is found that the specific heat ratio of bubbles in such syste...

We study surface nanobubbles using molecular dynamics simulation of ternary (gas, liquid, solid) systems of Lennard-Jones fluids. They form for a sufficiently low gas solubility in the liquid, i.e., for a large relative gas concentration. For a strong enough gas-solid attraction, the surface nanobubble is sitting on a gas layer, which forms in between the liquid and the solid. This gas layer is...

The in situ analysis of industrial processes, mostly conducted opaque equipment is difficult. Whereas previously the positron emission technique was successfully applied to study flow and mixing gas–solid liquid–solid systems using radio-active tracer particles, research on imaging a radio- active gas scarce. present paper demonstrates use fully three-dimensional (3D) Positron Emission Tomograp...