The propagation of light through powders differs significantly from the propagation of light in a homogeneous material, since the light scatters off points in its path. Colors of powders are related to the fineness of the powder, when the powder is illuminated with white light. As Fourier transform infrared has become more common, the diffuse reflection method has become widely used. Diffuse reflectance is an excellent sampling tool for powdered materials.

Electrocautery is a safe and effective method of hemostasis during cutaneous surgery. Despite the unquestionable benefits, electrocautery sparks in the surgical field represent a significant fire risk that can be eliminated by clarifying the causation and conditions of their development. Apart from the experimental methods, computer modeling is proven to be an effective approach to improve the performance of electrocautery. This paper is dealing with the design of electrodes to prevent burns during standard procedures. Simulations were carried out by using the COMSOL simulation package for various electrode configurations (cylinder-cylinder, sphere-sphere, sphere-cylinder, and cylinder-sphere) representing shapes of surgical electrodes. The primary goal was to determine the location where sparking starts. The obtained simulation results agree well with the experimental data taken from the literature supporting that the sparking formation is strongly affected by the electrode configuration. It was found that sparking occurs most easily when both electrodes are cylindrical. Also, the sparking mechanism depends on electrical asymmetry that results in undesirable direct current burns. Results presented here can be used to establish practices for the safe use of the electrocautery devices and to prevent injury to patients and staff.

Though a simple daily observation, evaporation of drops is still poorly understood due to the complex nature that involves hydrodynamic effects in the bulk fluids and transport phenomena at the liquid-vapor interface. This paper reports on the evaporation of single component droplets (water, ethanol, acetone, and glycerol) levitated in a single-axis non-resonant levitator. It was observed that the acetone and ethanol evaporated faster than water, although the acetone is the most volatile. The estimated lifetime of acetone is less than 5min, which is much shorter as compared to 56min for ethanol or about 90min for water droplets. On the other hand, glycerol showed no tendency to evaporate. With increasing the evaporation time, the ratio of large and small semi-axis decreases and tends to 1 corresponding to changes in drops shape from oblate ellipsoid to a sphere. Based on the classical D 2 -law, the surface regression rates have been estimated.