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In this work, the technical and economical feasibility for implementing a hypothetical electrolytic hydrogen production plant, powered by electrical energy generated by alternative renewable power sources, wind and solar, and conventional hydroelectricity, was studied mainly trough the analysis of the wind and solar energy potentials for the northeast of Brazil. The hydrogen produced would be exported to countries which do not presently have significant renewable energy sources, but are willing to introduce those sources in their energy system. Hydrogen production was evaluated to be around 56.26 x [10.sup.6] [m.sup.3] [H.sub.2]/yr at a cost of 10.3 US$/kg. Keywords: Renewable energy; Hydrogen production; Electrolysis; Hydrogen production cost

Duodenal ulcer, a condition in which the wall of the small intestine develops painful, sometimes bleeding lesions, is thought to result from an imbalance between the protective effects of the gastrointestinal mucosa (lining) and the destructive effects of hydrochloric acid produced by the stomach. A standard therapeutic approach to the treatment of duodenal ulcer is the administration of drugs that reduced gastric acid secretion. However, there is controversy over what might be the most effective regimen for administration of acid antisecretory or antacid drugs. Additionally, there has been debate over the effectiveness of over-the-counter (OTC) antacid medications which simply neutralize gastric acid (rather than preventing secretion, as most prescription ulcer medications do). A comparative evaluation of the effectiveness of a widely used antisecretory drug (cimetidine, a blocker of histamine H2 receptors) and an OTC antacid (magaldrate) was carried out in a group of 371 consecutive ulcer patients who were being treated at a Brazilian ulcer clinic. The standard therapeutic dose of cimetidine (800 milligrams) was given once per day to one group of patients, and one of three very-low-dose regimens of OTC antacid was given to the other groups of patients. The healing rates in the patients administered antacid were higher at both four and eight weeks than in the cimetidine group. Healing rates in this study were not affected by age, sex, symptoms at entry, presence or absence of night pain, or coffee consumption. In the cimetidine-treated group, smoking was associated with a slower healing rate, but there was no association between smoking status and healing rate in the antacid groups. (Consumer Summary produced by Reliance Medical Information, Inc.)

Mg-Zn-Zr (ZK) alloys exhibit notably high mechanical strength amongst all magnesium alloy grades. However, due to the formation of low melting point Mg 3 Zn 7 -precipitates, these alloys are susceptible to hot cracking, thus compromising their metallurgical processing. The addition of rare earths to ZK alloys is an alternative to form higher melting point intermetallic compounds, speed up dynamic recrystallization, refine grain size, enhance corrosion resistance and extend the service temperature due to improved creep resistance. This work deals with the effect of Ce-base mischmetal addition on the hot rolling behaviour of as-cast ZK60 alloy. The microstructure investigation conducted using electron microscopy and X-Ray diffraction shows that precipitation of Mg 7 Zn 3 intermetallics occur during hot rolling, whereas no further precipitation is observed for the ZK60-Mm alloys. The fragmentation of the intermetallic compounds occur during hot rolling and finer particles of Mg 7 Zn 3 are observed for the ZK60, whereas Mg 7 Zn 3 and MgZn 2 Ce intermetallics are formed in the alloy modified with mischmetal addition. A higher fraction of dynamically recrystallized grains is observed for the ZK60-Mm in comparison to the ZK60. Continuous recrystallization takes place in ZK60 with the formation of sub-grains near to the intermetallics and the addition of mischmetal promotes the occurrence of discontinuous recrystallization with the nucleation of new grains close to the precipitates. The mechanical strength and, in particular, the ductility of the hot-rolled alloys are notably improved when compared to the same alloys in the as-cast condition. The mechanical strength is, however, higher for the ZK60 alloy. Less solid solution strengthening, softer MgZn 2 Ce intermetallics and more extensive recrystallization contribute to reduce the mechanical strength of ZK60-Mm. Failure in both alloys are initiated at coarse intermetallics and propagate through intermetallic-rich regions. [ABSTRACT FROM AUTHOR]