Steffen Arnrich | PubMed Health

PubMed2006

Simultaneous adsorption at the liquid/solid and liquid/gas interfaces.

Physical adsorption from binary or higher-order liquid mixtures on solids is often accompanied by adsorption phenomena at the liquid/gas interface. As long as the adsorption effects are comparable, both interfaces have to be included in the respective thermodynamic equations. A purely phenomenological thermodynamic description in terms of excess quantities is given of the simultaneous adsorption from multicomponent liquid mixtures at the liquid/solid and liquid/gas interfaces. In order to illustrate the thermodynamic procedure, the individual and simultaneous adsorption excess isotherms of three binary liquid mixtures at the liquid/Teflon and liquid/vapor interfaces are calculated from experimental surface-tension and contact-angle data taken from the literature. Special attention is focused on the estimation of error in calculated adsorption isotherms. A line of approach is given to find the confidence limits of adsorption isotherms that cover the entire mole fraction scale. The isotherms as well as their confidence limits are presented and discussed.

Journal Article↗

PubMedDate not supplied

[Death by a cleaning pig--an unusual accident at work].

A worker was killed operating on a natural gas pipeline. At a receiver station the man intended to pick up two so called cleaning pigs, each weighing about 150 kg, diameter 0.5 m. For this purpose the gas pressure in the pig trap was let off by a valve, manometer controlled. According to an eyewitness's statement, the receiver pressure was equal to outside air pressure before the accident. The victim stood right in front of the flap of the receiver when he began to unfix the screws of the flap. Whilst working, the flap snapped out driven by the two cleaning pigs. The man and the devices were flung through a wire-netting fence and dropped down on a nearby field at a distance of 27, 29 and 38 m, respectively, from the receiver. The man died on the scene of the accident. The forensic autopsy ordered by the prosecution revealed signs of massive blunt trauma on the head, thorax and abdomen. In the criminological and forensic reconstruction of the accident the external injuries of the victim were found to be consistent with the front surface of the cleaning pig flung out first. It was determined that the second pig had got stuck in the receiver and that gas pressure had built up behind the pigs due to a leaky valve. As a consequence the pigs were expelled at a velocity of approximately 220 km/h causing a pattern of injury comparable to that of a fall from a great height.

Accidents, Occupational↗