Although many devices have recently been proposed for pressure regulation and energy harvesting in water distribution and transport networks, very few applications are still documented in the scientific literature. A new in-line Banki turbine with positive outflow pressure and a mobile regulating flap, named Power Recovery System (PRS), was installed and tested in a real water transport network for the regulation of pressure and flow rate. The PRS turbine was directly connected to a 55 kW asynchronous generator with variable rotational velocity, and coupled to an inverter. The start-up tests showed how automatic adjustment of the flap position and the runner velocity variation are able to change the characteristic curve of the PRS according to the flow delivered by the water manager or to the pressure set-point assigned downstream or upstream of the system, maintaining good efficiency values in hydropower production.

MmNi35AI,,Co,,7 has been characterized using electrochemical techniques and x-ray photoelectron spectroscopy. The stability and rapid hydriding and dehydriding kinetics that it exhibits in KOH have been attributed to the properties of a surface film. A hypothetical model of this film has been proposed in which stability results from an inner, dense barrier region that protects the thermodynamically unstable alloy from the electrolyte. Rapid reaction rates are attributed to the high concentrations of metallic cobalt and nickel present in the film. A continuous electron-conducting network composed of these two metals is proposed that allows electron transfer between the bulk intermetallic and the outer regions of the film where solution species participating in the reactions are readily available.Infroduction AB, intermetallic compounds have been recognized as potential negative electrodes for alkaline nickel-metal hydride batteries since Justi et al. described the high hydrogen storage capacity of LaNi5 in KOH in 1970.' Since that time, extensive chemical substitutions and processing modifications have been carried out to improve the stability of LaNi,, and in general, to optimize the resulting AB5 compounds for commerciali.zation.2" One of the more

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The highly oxidizing and acidic environment experienced by the positive plate in telecommunications lead-acid batteries severely limits the choice of positive grid materials. Currently, grids are made from pure lead or lead-based alloys. Although long-lived batteries have been obtained using pure lead grids with complex designs, the need for thick grids coupled with the high density of lead results in batteries with low energy density. Energy density improvements could be achieved if thinner lead grids or thin grids made from less dense materials could be employed. Many approaches t o controlling the corrosion and growth rate of lead-based grids as well as to the use of alternative materials have been reported in the literature. This paper provides an indepth evaluation of the strengths and weaknesses of these approaches based on the characteristics associated with a viable grid material.

This article examines the old and the state-of-the-art in batteries.