An experimental study has been carried out of the two phase counter-current gas-liquid flow in a packed bed column operated in the proximity of the flooding point under periodic variations of inlet velocity of gas or liquid. Additional experiments have been focused on evaluating axial dispersion characteristics in the proximity of the flooding line in both liquid and gas phase using inert trace...

The mass transfer performance of a pulsed disc and doughnut column for extraction of samarium and gadolinium from aqueous nitrate solution with D2EHPA was investigated. The effects of operating parameters such as pulsation intensity, continuous and dispersed phase velocities on column performance were investigated. The axial dispersion model was used to obtain the overall mass transfer coef...

Models were developed for prediction and interpretation of the observed steady-state axial dissolved oxygen concentration profiles in tall airlift bioreactors. The observed concentration profiles were non-linear because of a combination of hydrodynamic and mass transport factors. The profiles were influenced mainly by the liquid-phase axial dispersion coefficient, the volumetric overall gas–liq...

The metabolic function of synovial fluid is important to understand normal and abnormal synovial joint motion, especially if one seeks some leading causes of the degenerative joint disease. The concentration of hyaluronic acid molecules and other high molecular weight substances in the synovial fluid may be responsible to disperse the nutrients into the cartilage. The theoretical study of the c...

In this paper an observability analysis is performed for an axial dispersion tubular bioreactor that involves one nonlinear growth reaction. The process is described by a semilinear parabolic Partial Differential Equation (PDE). More precisely, the analysis is performed on a tangent linearized model, that is described by a linear PDE with a spatial-dependent coefficient. It is reported that the...

We investigated the axial dispersive effect of the upper airway structure (comprising mouth cavity, oropharynx, and trachea) on a traversing aerosol bolus. This was done by means of aerosol bolus experiments on a hollow cast of a realistic upper airway model (UAM) and three-dimensional computational fluid dynamics (CFD) simulations in the same UAM geometry. The experiments showed that 50-ml bol...

In this paper, a new structure is provided for the dispersion compensating photonic crystal fibers in order to broaden the chromatic dispersion and increase the dispersion compensating capability in a wide wavelength range. In the structure, putting a combination of circular holes and a star structure in the inner core clad causes the dispersion coefficient profile to be broadened, and addition...

design models of multi- stage, axial flow compressor are developed for gas turbine engines. axial flow compressor is one of the most important parts of gas turbine units. therefore, its design and performance prediction are very important. one-dimensional modeling is a simple, fast and accurate method for performance prediction of any type of compressors with different geometries. in this appro...