MONITORING OF CORROSION UNDER CATHODIC PROTECTION CONDITIONS UTILIZING COUPLED MULTIELECTRODE SENSORS
Real-time corrosion monitoring for carbon steel materials in simulated seawater under cathodic protection conditions was conducted, utilizing coupled multielectrode sensors. It was demonstrated that the coupled multielectrode sensor is an effective real-time tool for monitoring the effectiveness of cathodic protection and for measurement of the threshold value of the protection potential for specific equipment.
MEASUREMENT OF CORROSION IN SATURATED SOLUTIONS UNDER SALT DEPOSITS USING COUPLED MULTIELECTRODE ARRAY SENSORS
The corrosion rates of type 1010 carbon steel, and types 304 and 316 stainless steels in saturated solutions under salt deposits were measured using coupled multielectrode sensors. The measurements were carried out in the presence of the following salts: KCl, NaCl, NaNO3, MgCl2, NiCl2, FeCl3, FeCl2, CuCl2, and an NaCl+NaNO3 mixture. The results indicate that the corrosiveness of the salts increased in the following order: KCl ~ NaCl ~ NaNO3 ~ NaCl+NaNO3 ~ MgCl2 < NiCl2 < FeCl3 < FeCl2 < CuCl2 for carbon steel, and KCl ~ NaCl ~ MgCl2 ~ NiCl2 ~ NaCl+NaNO3 < FeCl3 ~ FeCl2 ~ CuCl2 for type 304 stainless steel. Some inhibition of corrosion of type 316 stainless steel by NaNO3 was observed in a mixture of NaCl+NaNO3, but not in pure NaNO3 solution.
Influence of inducers and inhibitors on the metabolism in vitro and neurochemical effects in vivo of MDMA.
(S)-(+)- and (R)-(-)-3,4-methylenedioxymethamphetamine (MDMA) were metabolized in vitro by rat liver microsomes via N-demethylation to 3,4-methylenedioxyamphetamine (MDA). Whereas no difference was found in the biotransformation of the two enantiomers in the male rat or in the phenobarbital (PB) treated animals of either sex, more than twice as much MDA was formed from (S)-(+)- than from (R)-(-)-MDMA in the untreated female rat. Although 3-methylcholanthrene (3MC) pretreated rat liver microsomes were less active than those from the untreated rats of the same sex, they formed more MDA from (+)- than from (-)-MDMA. The enantioselective metabolism thus appears to be associated with the relative abundance of individual cytochrome P-450 isozymes. (S)-(+)- and (R)-(-)-MDMA.HCl (20 mg/kg) were about equipotent in depleting serotonin (5-HT) levels in the frontal cortex at 3 hrs and 1 wk following oral administration to female rats. Pretreatment of rats with SKF-525A attenuated and that with PB enhanced the 5-HT depleting potential of either isomer at 3 hrs. The 5-HT depleting potency of (+)-MDMA was significantly greater than that of its (-)-antipode at 3 hr in PB pretreated, but not in SKF-525A pretreated animals. The results suggest that the neurochemical effects of MDMA are caused by the formation of an active metabolite in vivo, and since both enantiomers were N-demethylated in vitro to approximately the same extent by PB pretreated rat liver microsomes, the active metabolite may be other than MDA.