Sharif Digital Repository

In this paper, we studied the behavior of liquid sheet and jet injection into a low-speed crossflow. Characteristics of primary breakup in a liquid sheet and jet are investigated for circular and rectangular orifices. Effect of dimensionless numbers on primary breakup regimes including jet trajectory, length, height, breakup, and spray characteristics are surveyed by the shadowgraphy technique at ambient pressure and temperature. Tests were performed in the range of 0.8–16.57 for the Weber number, 5–250 for the momentum flux ratio, and 380–1850 for the Reynolds number. This comprehensive study on rectangular jets in crossflow leads to introduce the transition regions of the primary... 

Here, we experimentally investigated the effects of skewness and velocity difference of two Newtonian colliding jets on the formation of a special oscillating liquid sheet pattern with periodic fragmentation, called fishbone, for four liquid sheet regimes known as the triple chain, double chain, close rim, and open rim. We expressed the ranges of the skewness and the velocity difference, where the fishbone pattern was formed for every four regimes. The formation of this special pattern was attributed to the instability of the liquid rim in the past studies. We qualitatively studied the upward and downward directions of the rims branched from the liquid sheet. Besides, the size variations of... 

Ionic liquids are a significant type of organic salts with attractive and superior physicochemical features for employing in a number of chemical processes. Ionic liquids include one large and asymmetric cationic or anionic functional group. The properties of cationic functional group are almost similar and it is main motivation of this study. In the present investigation, we extended various semi-empirical correlations to predict some temperature-based properties of ionic liquids mixture (IL-mixture). These properties are density, viscosity, surface tension and bubble point pressure. In the case of IL-mixture density, modified Rackett equation and Taylor equation with three scenarios,... 

In this study, the prediction of excess molar volume of ionic liquid + solvent binary system is described using modified two-parameter and three-parameter cubic equation of state (CEoS). The studied binary systems are consisted of 41 ionic liquids, 40 solvents and 5293 data point in the wide temperature range (278.15–353.15 K), ionic liquid mole fraction (0.0036–0.9920) and atmospheric pressure i.e. P = 1 bar. At the first step, the volume-translated parameter (c) was obtained based on three linear, distance function and exponential-type temperature-dependent cases and using experimental pure density. After that, and due to easy-to-use of c-parameter, various formula was presented based on... 

Background: Studying the kinematics of the ACL deficient (ACLD) knees, during different physiological activities and muscle contraction patterns, can improve our understanding of the joint's altered biomechanics due to ACL deficiency as well as the efficacy and safety of the rehabilitations exercises. Methods: Twenty-five male volunteers, including 11 normal and 14 unilateral ACLD subjects, participated in this study. The kinematics of the injured knees of the ACLD subjects was compared with their intact knees and the healthy group during passive flexion and isometric leg press with the knees flexed from full extension to 45° flexion, with 15° intervals. An accurate registration algorithm... 

STUDY DESIGN.: An experimental design to investigate activation patterns of trunk muscles during multidirectional exertions. OBJECTIVES.: To evaluate trunk muscle activation patterns in varying directions and moment magnitudes during an isometric task, and to investigate the effects of angle and level of isometric exertion on the electromyography (EMG) variability of trunk muscles in upright posture. SUMMARY OF BACKGROUND DATA.: Few studies have investigated trunk muscle activation patterns in multidirectional exertions with different moment magnitudes. METHODS.: A total of 12 asymptomatic male subjects were participated in the study. The EMG activity of 10 selected trunk muscles was... 

The corrosion behavior of different grades of commercial aluminum such as AA1040, AA5083, AA6060 and AA7075 in ZnO-containing 4 M NaOH has been determined by using open circuit potential-time measurements (OCP), galvanostatic and potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results of scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX) reveal that ZnO produces the inhibition effect by the formation of a zinc-containing deposit layer on the surface of aluminum electrodes. Although the influence of zincating on the performance of aluminum alloys and considering the amount of alloying elements such as zinc, magnesium and...