The hydrodynamics of a co-current down flow bubble column has been investigated with air – water system. A Perspex bubble column of 5cm in diameter and 1.5m height is used as a test contactor using nozzles of 7, 8 and 9 mm diameter for air-water distributing. The column is provided with three electro-resistivity needle probes for bubble detection.
Experimental work is carried out with air flow rates from 0.09 to 0.45 m3/hr and liquid flow rates from 0.65 to 1.1m3/hr in order to study the effects of superficial gas velocity, nozzle diameter and liquid flow rate on the characteristics of hydrodynamic interactions viz. gas hold up, bubble diameter and bubble velocity by using two technical methods, direct height measurements for air-water mixture in the column and resistivity probe techniques.
Gas hold up is found to be progressively increased with increasing superficial gas velocity and with decreasing liquid flow rate. Lower gas hold up is obtained with smaller nozzle diameter. However, gas hold up in two-phase zone is considerably higher than the corresponding value in mixing zone.
The mean bubble velocity is increased with increasing superficial gas velocity, liquid flow rate and nozzle diameter for both mixing and two phase zones. Experimental data are found to be fairly fitted with the Drift Flux model of Zuber and Findly.
The bubble diameter is considerably increased with increasing superficial gas velocity and with decreasing liquid flow rate, whereas it is slightly influenced by nozzle diameter. However, the bubbles in two-phase zone are relatively bigger than those observed in mixing zone. Finally, mathematical correlations have been developed from the experimental data to describe the gas hold up and bubble velocity in the uniform two-phase zone.
The research aims to improve the performance of the Directorate of Maysan water by reconciling the objectives of the employees of the directorate with the objectives of the Directorate itself, as well as to identify the strengths and weaknesses in the performance of the Directorate (Leadership - Individuals - Knowledge - Operations - Financial) and presented to experts and arbitrators of specialized, and the researchers have relied on the case study methodology as a descriptive approach is comprehensive analysis, and draws on more than one approach, method and scientific design, has been interviewed a number of experts in the Directorate Maysan's water Identify the weaknesses and strengths of the Directorate, the research has rea
... Show MoreSurface wettability plays a significant role in determining the function of the wound dressing. They should have hydrophobic surfaces for the adsorption of bacteria and a hydrophilic surface necessary to improve cell attachment for most anchorage-dependent cell types. Furthermore, the Hydrophobicity / Hydrophilicity of the surface can be used to direct cellular processes such as cell initial correlation, adhesion, and migration during wound healing, as a result such surface can change its surface wettability which increases the dressing's usefulness.
In this research, nanomembres were prepared from polycaprolactone and chitosan solution (with different amounts of CS (0.05, 0.1, 0.2, and 0.4) % (w/w)) by the electrospinning m
... Show MoreIn this work, the emission spectra and atomic structure of the aluminum target had been studied theoretically using Cowan code. Cowan code was used to calculate the transitions of electrons between atomic configuration interactions using the mathematical method called (Hartree-Fock). The aluminum target can give a good emission spectrum in the XUV region at 10 nm with oscillator strength of 1.82.
The hydrodynamic properties of laser produced plasma (LPP) were investigated for the purpose of creating a light source working in the EUV region. Such a light source is very important for lithography (semiconductor manufacturing). The improved MEDUSA (Med103) code can calculate the plasma hydrodynamic properties (velocity, electron density,
In this paper, we study the impacts of variable viscosity , heat and mass transfer on magneto hydrodynamic (MHD) peristaltic flow in a asymmetric tapered inclined channel with porous medium . The viscosity is considered as a function of temperature. The slip conditions at the walls were taken into consideration. Small
Reynolds number and the long wavelength approximations were used to simplify the governing equations. A comparison between the two velocities in cases of slip and no-slip was plotted. It was observed that the behavior of the velocity differed in the two applied models for some parameters. Mathematica software was used to estimate the exact solutions of temperature and concentration profiles. The resolution of the equatio
Background: Adenosine mediates homodynamic
changes and resulted in the production of acute renal
failure (ARF) in female Albino-Wister rats, therefore,
adenosine level increases highly in ARF.
Objective: This experiment was designed to
investigate the effect of the adenosine antagonist
aminophylline and the adenosine agonist indomethacin on glycerol-induced ARF.
Method: Glycerol induced ARF was produced by a
single dose (10ml/kg, 50%v/v with distilled water i.m)
in rats, which were restricted to drinking water.
Aminophylline was used in our study in a dose of
25mg/kg, i.p) while the dose of indomethacin was
10mg/kg, i.p), assessment of renal function was done
by measuring blood urea
nitrogen (BUN
The traffic congestion caused by the increase in the number of vehicles in the cities as a result of the increase in the population and the density of construction requires the provision of appropriate infrastructure and the provision of transport systems and logistics services that meet the needs of the population to meet the many challenges now and in the future by introducing various modes of transport , In accordance with integrated plans such as the use of (pedestrian friendly environments, bicycles and their own paths, light rail, metro, express bus, as well as public transport buses and others), through the development of Projects High-level roads, such as the annual and major roads, etc., and integrated with the urban planning of
... Show MoreShallow foundations are usually used for structures with light to moderate loads where the soil underneath can carry them. In some cases, soil strength and/or other properties are not adequate and require improvement using one of the ground improvement techniques. Stone column is one of the common improvement techniques in which a column of stone is installed vertically in clayey soils. Stone columns are usually used to increase soil strength and to accelerate soil consolidation by acting as vertical drains. Many researches have been done to estimate the behavior of the improved soil. However, none of them considered the effect of stone column geometry on the behavior of the circular footing. In this research, finite ele
... Show MoreTheoretical calculations are achieved to study the effect of different deuterium pressures on various characteristics parameters for PF400J plasma focus using an international computer code. Axial and radial velocities, voltage tube, plasma temperatures, and neutron yields at different operating deuterium pressures are computed. Neutron emission has been calculated in the device. The maximum total neutron yield calculated is of the order of and neutrons per shot for entire pressure used. The computed results agree reasonably well with the published neutron yield curves.