A numerical model that simulates airway closure by liquid bridging during expiration has been developed. The effects of both surfactant and time-varying geometry have been included; the model determines the liquid layer flow resulting from a surface tension (Rayleigh) instability, and the computation traces the film's development to closure, yielding pressure, velocity, surface shape, and surfa...

in order to compare effect of magnetic field and frigate surfactant to enhance the efficacy of iodosulfuron-methyl-sodium plus mesosulfuron-methyl (chevalier) to control wild oat, a greenhouse experiment of dose-response was conducted. treatments were 0, 3, 6, 12, 18 and 24 doses g a.i. ha-1 of chevalier (i) without treatment, (ii) with frigate % 0.1 v/v, (iii) with magnetic field, and (iv) fri...

Transport of colloids with transient wetting fronts represents an important mechanism of contaminant migration in the vadose zone. The work presented here used steady-state saturated and transient unsaturated flow columns to evaluate the transport of a fluorescent latex microsphere (980 nm in diameter) with capillary wetting fronts of different solution surface tensions and ionic strengths. The...

A linear analysis, employing the lubrication approximation, is presented for the leveling history of a thin layer of Newtonian liquid. When the surface tension is taken to be constant, the classic result of Orchard is reproduced. As expected, the presence of surfactant, with resulting surface-tension-gradient forces, slows the rate of leveling of an initial train of periodic ripples. For very w...

High liquid entry pressure (LEP) is one of the desired characteristics of a membrane distillation (MD) membrane. Maintaining LEP above operating feed pressure conditions is critical to prevent permeate quality worsening by saline feed liquid passage through the membrane. Air gap membrane distillation experiments under controlled salinity and temperature operating conditions indicate that in add...

Damselfly larvae, important predators and prey in many freshwater communities, may be particularly sensitive to hypoxia because their caudal lamellae (external gills) are frequently lost. In this study, we address how lost lamellae interact with low oxygen to affect respiration and behavior of the widespread North American damselfly Ischnura posita. Results showed no effect of lost lamellae on ...

This paper studies the evolution mechanism of surface rippling in polymer nanofibers under axial stretching. This rippling phenomenon has been detected in as-electrospun polyacrylonitrile in recent single-fiber tension tests, and in electrospun polyimide nanofibers after imidization. We herein propose a one-dimensional nonlinear elastic model that takes into account the combined effect of surfa...

We present a simulation of the liquid-vapor interface of argon with explicit inclusion of the three-body interactions. The three-body contributions to the surface tension are calculated using the Kirkwood-Buff approach. Monte Carlo calculations of the long-range corrections to the three-body contribution are calculated from the radial distribution function g((2))(z1, cos θ12, r12). Whereas the ...

A series of novel dissymmetric gemini cationics surfactants was synthesized by three-step reactions. The dissymmetric gemini surfactants contain a dodecanoic acid dimethylethylamine ester as the constant cationic part on one side of the hydroxypropyl center and a similar other cationic part, but with a different acid length (from octanoic to palmitic), on the other side. The critical micelle co...

The interaction between turbulence and surface tension is studied through direct numerical simulation of a canonical multiphase flow. An initially flat interface is inserted into a triply periodic box of decaying homogeneous isotropic turbulence, simulated for a variety of turbulent Reynolds and Weber numbers on mesh sizes of 512 and 1024. Unity density and viscosity ratios are used in order to...