We tested the hypothesis that birds can rapidly change the conductance of water vapor at the skin surface in response to a changing need for evaporative heat loss. Mourning doves (Zenaida macroura) were placed in a two-compartment chamber separating the head from the rest of the body. The rate of cutaneous evaporation was measured in response to dry ventilatory inflow at three ambient temperatu...

A numerical and experimental investigation was conducted to analyze dropwise evaporative cooling of heated surfaces with various wettability characteristics. The surface wettability was tuned by nanostructure modifications. Spray-cooling experiments on these surfaces show that surfaces with better wettability have better heat transfer rate and higher critical heat flux (CHF). Single droplet imp...

Microfluidic devices that reduce evaporative loss during thermal bioreactions such as PCR without microvalves have been developed by relying on the principle of diffusion-limited evaporation. Both theoretical and experimental results demonstrate that the sample evaporative loss can be reduced by more than 20 times using long narrow diffusion channels on both sides of the reaction region. In ord...

[1] During the Marine Stratus/Stratocumulus Experiment, cloud and aerosol microphysics were measured in the eastern Pacific off the coast of northern California on board Department of Energy Gulfstream-1 in July 2005. Three cases with uniform aerosol concentration and minimal drizzle concentration were examined to study cloud microphysical behavior. For these three cases, the average droplet nu...

Sprinkler and Fan Cooling Principles In sprinkler and fan cooling, the sprinklers create droplets that wet the cow’s hair coat to the skin. Fans are then used to force air over the cow’s body (see Figure 1), causing evaporative cooling to take place on the skin and hair coat. Heat from the cow’s body causes the moisture to evaporate. The droplet size must be large enough to wet the skin surface...

A novel method for preparing samples for use in MALDI-TOFMS (matrix-assisted laser desorption ionization time-of-flight mass spectrometry) is described. Seven hydrolysis products derived from nitrogen mustards and CHCA (alpha-cyano-4-hydroxycinnamic acid) were selected as model compounds and the matrix, respectively. A capillary atomizer was used for evaporative and spray deposition of the samp...

Digital microfluidic chips provide a new platform for manipulating chemicals for multi-step chemical synthesis or assays at the microscale. The organic solvents and reagents needed for these applications are often volatile, sensitive to contamination, and wetting, i.e. have contact angles of <90° even on the highly hydrophobic surfaces (e.g., Teflon® or Cytop®) typically used on digital microfl...

  Spreading and coating of nano and micro droplets on solid surfaces is important in a wide variety of applications including plasma spray coating, ink jet printing, DNA synthesis and etc. In spraying processes, most of droplets collide obliquely to the surface. The purpose of this article is to study the distribution of nano and micro droplets spreading when droplets impact at an oblique a...

Although the evaporation mode of sessile droplets is almost universally characterized as either constant contact radius (CCR) or constant contact angle (CCA), here we investigate two alternatives where the contact line speed is either constant or inversely proportional to the droplet radius. We present supporting evidence from our experiments on poly(ethylene oxide) (PEO) polymer solutions and ...

Exact analytical solutions are derived for the Stokes flows within evaporating sessile drops of spherical and cylindrical cap shapes. The results are valid for all contact angles. Solutions are obtained for arbitrary evaporative flux distributions along the free surface as long as the flux is bounded at the contact line. Specific results and computations are presented for evaporation correspond...