the effects and influences of various parameters upon the efficiency and the overall volumetric mass transfer coefficients are important subjects to be studied in most liquid-liquid extraction processes. one of these important parameters is surface active agent (surfactant). in this paper, in order to study the effect of sodium dodecyl sulfate (sds) concentration on the efficiency and the avera...

this paper presents a numerical study of local mass transfer coefficients in a 90° bend using the rng version of k–e model to include the influence of curvature on the turbulent transport. simulations were performed for flow through a 90°, 3-d bend for reynolds numbers of 13500, 90000, and 390000, schmidt numbers of 2.53 and 700 and curvature ratios of 1.5, 2, and 2.5. the differences between t...

this paper modeled heating air of a room through examining free convection in a 3d chamber. the chamber had cold and hot sources with tc and th temperatures, respectively. its other walls were adiabatic. this study aimed at predicting effect of temperature difference, displacement of hot and cold sources and their aspect ratio on flow field, temperature and heat transfer rate. to conduct the st...

in the present paper, an analysis was carried out to investigate effects of radiation on a free convection flow bounded by a vertical surface embedded in a porous medium with constant suction velocity. it was under the influence of uniform magnetic field in the presence of a homogenous chemical reaction and viscous dissipation with constant heat and mass flux. the non-dimensional governing equa...

the effect of a distributed patch mass on the natural frequency of vibration of a laminated rectangular plate with simply supported boundaries is investigated. the third order displacement field of a composite laminated rectangular plate is defined using the two variable refined plate theory. equations of motion of the plate are obtained with the help of calculus of variation. parametric study ...

The main objective of this paper is to examine the effect of nanomaterials on mass transfer coefficient in bubble type absorption of carbon dioxide by experiment. The absorption process is carried out in a bubble column and in room temperature. Mass transfer coefficient, saturated concentration of CO2, and gas holdup are determined in this system. The kinds of nanomaterials, the concentrations ...

in upper brachial plexus (c5-c6 or c5-c6-c7 roots) injuries, restoration of elbow flexion is the first aim. several methods have been used to achieve this goal. among these procedures, oberlin’s method (transfer of part of ulnar nerve to the nerve to biceps muscle) is the newest one. from april 2002 to march 2003 we used this method in 9 cases, 8 males and 1 female, of upper brachial plexus inj...

the purpose of this investigation was directed to propose sensitive, accurate and reproducible methods of analysis that can be applied to determine distigmine bromide (dtb), cyclopentolate hydrochloride (cphc), diaveridine hydrochloride (dvhc) and tetrahydrozoline hydrochloride (thhc) drugs in pure form and pharmaceutical preparations via charge-transfer complex formation with 7,7,8,8-tetracyan...