This paper presents a methodology for calculation of a slug, two-phase fLow hold-up in a horizontal pipe. The advantage of this method is that the slug unit hold up can be calculated directly from the solutions of fLow field equations with no need to use correlations. An experimental apparatus to measure air-water hold up was setup. The fLow pattern and liquid holdup in horizontal and inclined pipes, from angles 5o to 40o, for air-water two-phase fLow, are experimentally observed. The test section, with an inside diameter of 30 mm and 3 m in length, was made of plexy-glass to permit visual observations of the fLow patterns. The proposed model was tested extensively against experimentally collected data. Furthermore, other data sources for slug fLow in horizontal pipes, for air-water and air-oil systems, were also used for comparison. The presented methodology was compared against four recently developed models of a two phase, slug fLow holdup in horizontal pipes. Not only does the presented model demonstrate good agreement, with less than 6.8% error, compared to the experimental data, but also has less error compared to other models. These results substantiate the general validity of the model.

Existing liquid holdup models are generally based on Low gas and liquid velocities. In order to extend the applicable range of existing liquid holdup prediction models and improve its prediction accuracy, a of gas-liquid two-phase fLow experiment was carried out using a pipe of inner diameter 60mm and length of 11. 5m. The superficial gas and liquid velocity ranges were 14. 07~56. 50m/s and 0. 205~1. 426m/s, respectively. The results indicate that the liquid holdup decreases with the increase of the superficial gas velocity and increases with the increase of the superficial liquid velocity. A new annular fLow model for calculating Low liquid holdup in horizontal pipe was developed and presented considering the relationships between the friction factor ratio of liquid phase and gas-liquid interface as well as the superficial Reynolds number of gas and liquid. The predictions of the model are found to be accurate with an average absolute error of 4. 8%. Further, on the basis of the Beggs-Brill model and the horizontal pipe model established in this paper, a new liquid holdup model for different angles was given. It was observed the resultant model is also accurate, and has an average absolute error of 10%.

holdup was measured at various frequencies, amplitudes, continuous and dispersed phase fLow rates for binary systems in a pulsed plate column capable of providing samples at various heights. The binary systems were so selected as to cover a wide spectrum of interfacial tensions. Dispersed phase holdup was found to increase with height in a logarithmic fashion at conditions away from the flooding point and to become almost invariant with height near flooding conditions.The interfacial tension of the binary system has a large effect on the dispersed phase holdup. In systems having Low interfacial tension, a small increase in any of the parameters can increase the holdup significantly and lead to flooding. In systems having high interfacial tension, on the other hand, variations in system parameters do not affect system performance significantly.

In this paper a two impinging streams cyclone contacting system suitable for handling of solid-liquid systems has been studied Certain pertinent parameters such as: solid holdup, mean residence time and Residence Time Distribution (RTD) of solid particles have been investigated A stochastic model based on Markov chains processes has been applied which describe the behavior of solid particles in the contacting system.From this model the RTD data were estimated and compared with the experimental results. The RTD data were obtained at different D t and compared with those estimated from the model. At Dt = 0.362 s a good correlation has been observed between the predicted and experimental data. The RTD data may be used to determine certain pertinent characteristic parameters of physical and chemical apparatuses such as conversion in chemical reactors.

Background & Objective: The papanicolaou (pap) smear has been used to screen women for cervical cancer since 1940. Unsatisfactory results induce anxiety in patients and doctors. Recently, a number of new technologies have been developed to improve the detection of cervical cancer. Increase the early detection of meaningful pap smear abnormalities, reduce the number of unsatisfactory smears and false negative results and provide fewer ambiguous results one of these method is the new test, include liquid-based to improve the quality and quantity of the cervical pap smear. The aim of this study is to evaluate rate of unsatisfactory smear of cervical cytology in two methods, conventional pap smear (CP) and liquid-Based (L.B).Materials & Methods: A comparison cross – sectional study was performed from 2004-2005 on 1500 patients referred to the Ghaem hospital and private clinic. From all patients cervical cytology was taken randomly via two methods CP and L.B. Subsequently frequency unsatisfactory cervical cytology in tow methods evaluated. Statistical analysis using the SPSS soft ware was done and t-test and c2 used for comparative evaluation.Results: Considering the incidence of unsatisfactory cervical cytology in CP method %0.3 was and in LB method %1 was. Sensitivity of the C.P method was 68.8% and that of the L.B method was 83.1%.Conclusion: In this study incidence unsatisfactory rate in L.B method was higher than C.P method.

In the present work, dispersed phase holdups have been measured in a Hanson mixer-settler extraction pilot plant with seven stages for two different liquid-liquid systems. The effects of agitation speed, dispersed and continuous phase fLow rates have been investigated under a variety of operating conditions. Dispersed phase axial holdup profiles, determined by a sampling method, showed a strong nonuniformity. The results also showed that the dispersed phase holdup changes largely with the direction of mass transfer. Finally, an empirical correlation in terms of physical properties of liquid systems and operating variables was proposed to predict the holdup and good agreement between experimental data and calculated values of holdup was obtained.

Hydrodynamic aspects of a bench scale “Autocirculation” reactor for single step hydrogen sulfide removal at Low temperatures using an iron chelate catalytic solution were investigated. Considering reactor behavior and internal geometry, the concept of airlift reactors will be employed ultimately for design, simulation and scale-up in further developing stages of a research project. As a first step, determination of two key hydrodynamics parameters, i.e. liquid circulation velocity and gas holdup have been investigated. The liquid circulation velocity and gas holdup in the riser were obtained using the tracer response technique and the manometric method, respectively. Air and water were used as working fluids for gas and liquid phases. Correlations that express variations of these two parameters with superficial gas velocity were presented. Results reveal that liquid velocity and gas holdup increase with increasing superficial gas velocity in the form of power functions. A mathematical model was developed to predict hydrodynamic parameters of the reactor. A comparison of the experimental data and the model predictions shows a good agreement.