Flushing pulsed

SAFETY PROFILE Moderately toxic to humans by an unspecified route. Moderately toxic experimentally by intravenous and intraperitoneal routes. Mildly toxic by skin contact. Human systemic effects by ingestion or inhalation flushing, pulse rate decrease, blood pressure lowering, anesthesia, narcosis, headache, di22iness, mental depression, hallucinations, distorted... 

FIGURE 14.10 Transient absorption spectra observed following pulse radiolysis of 1 x 10-4 M ASTA with 1 x 10-5 M LYC in argon flushed benzene. 

Chemisorption measurements (Quantachrome Instruments, ChemBET 3000) were conducted in order to determine the metal (Co) dispersion. Therefore, the nanomaterial catalysts were reduced under a hydrogen flow (10% H2 in Ar) at 633 K for 3 h. The samples were then flushed with helium for another hour at the same temperature in order to remove the weakly adsorbed hydrogen. Chemisorption was carried out by applying a pulse-titration method with carbon monoxide as adsorbing agent at 77 K. The calculation of the dispersion is based on a molar adsorption stoichiometry of CO to Co of 1. 

In such a case,pulse techniques can be conveniently used to examine the reactivity of the adsorbed species as follows. After the catalyst had been reduced by a pure stream at 160°C for 2 hrs, the catalyst bed was flushed by He and then the sream changed to an 2 (12.8%) -He stream. O2 and 0 gases were separa-... 

A 20-year-old man employed in a photographic darkroom suffered attacks of numbness, weakness, vertigo, some nausea, rapid pulse, and flushing of the face after 1 h of work (Parmenter 1926). Two other workers were unaffected. Following improved ventilation in the room, cyanide was measured in several areas of the workroom, including over a sink into which ferrous sulphate and potassium cyanide were routinely disposed. Concentrations of cyanide at that time (with the improved ventilation) ranged from 25 to 75 ppm. 

As noted above for the AEGL-1, chronic occupational exposure of adult males to >10 ppm produced symptoms of headache, weakness, changes in taste and smell, irritation of the throat, vomiting, and effort dyspnea (El Ghawabi et al. 1975 NIOSH 1976 Blanc et al. 1985). For a few individuals, chronic exposures occasionally produced more serious adverse effects, such as fainting and psychotic episodes. There was no evidence that these symptoms occurred after one exposure. A concentration of >25 ppm for 1 h resulted in numbness, weakness, vertigo, nausea, rapid pulse, and flushing of the face (Parmenter 1926). Only one individual was involved, and neither the exposure duration nor the concentration were measured. 

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