Predicting the Splash of a Drop Impacting a Thin Liquid Film.

An experimental study is carried out to investigate droplet-film interactions when a drop impinges on a thin stagnant film of the same liquid. The impacting drop causes either liquid deposition or splash, consisting of prompt generation of secondary drops or a delayed process. By varying the drop diameter and impact velocity, measurements are made to characterize the phenomena using five different liquids that are chosen to cover a wide range of liquid properties (viscosity and surface tension).

Acoustic droplet vaporization-mediated dissolved oxygen scavenging in blood-mimicking fluids, plasma, and blood.

Acoustic droplet vaporization (ADV) has been shown to reduce the partial pressure of oxygen (PO) in a fluid. The goals of this study were three-fold: 1) to determine the ADV pressure amplitude threshold in fluids that had physiologically relevant values for surface tension, protein concentration, and viscosity; 2) to assess whether these parameters and fluid mixing affect ADV-mediated PO reduction; and 3) to assess the feasibility of ADV-mediated PO reduction in plasma and whole blood. In vitro ADV experiments were conducted using perfluoropentane droplets (number density: 5 × 10 ± 0.

Surfactant-induced modification of low weber number droplet impact dynamics.

The effect of surfactant molecular mass transport on the normal impact and spreading of a droplet of its aqueous solution on dry horizontal substrates is investigated experimentally for a range of Weber numbers (20-100). The postimpact dynamics of film spreading and its recoil behavior are captured using high-speed real-time digital imaging. Hydrophilic (glass) and hydrophobic (Teflon) substrates were used with water and aqueous solutions of three different surfactants of varying diffusion rates and ionic characteristics: SDS (anionic), CTAB (cationic), and Triton X-100 (nonionic).

Analgesia for the reduction of Colles fracture. A comparison of hematoma block and intravenous sedation.

Objective: An alternative to general anesthesia was tested against conventional sedation by a double-blind, randomized clinical trial in reduction of Colles fracture.

Settings: A large teaching hospital where cases of Colles fracture are not different from those seen in district hospitals.

Patients: Sixty-six out of 80 consecutive cases with this fracture were selected from March to August 1990 on the basis of: 1) informed consent; 2) no contraindication to any method of analgesia; 3) no analgesic during the past 8 hours; 4) injury duration less than 96 hours; 5) no mental, auditory, or visual impairment; and 6) no associated injury.