Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, C.P. 04510, México Distrito Federal, México Departamento de Ecología de la Biodiversidad, Estación Regional del Noroeste, Instituto de Ecología, Universidad Nacional Autónoma de...

ÐPhysically conditioned water, made by passage between the poles of a magnet or by injecting a weak electrical signal, is used for the prevention and removal of lime-scale, but also has diverse biological e€ects. In this investigation, we have shown both stimulations and inhibitions of the multiplication of yeast cells, depending on the degree of conditioning. Weakly conditioned water is stimul...

In several process plants the precision of parameter estimates is low because the installed set of instruments do not satisfy the new information requirements for different purposes, from simple data reconciliation to on-line optimization. This paper presents models to perform the upgrading of instrumentation at minimum cost to achieve maximum precision of selected parameters. Alternative equiv...

ÐBiosorption of Cd by biomass of the brown seaweeds Durvillaea, Laminaria, Ecklonia and Homosira presaturated with Ca, Mg or K was coupled with the release of these light ions. The feasibility of biomass pre-treatment to develop a better biosorbent was evaluated by its biosorption performance, the degree of its component leaching (measured by the weight loss and TOC) as well as by the number of...

Constructed wetlands could be components of low-tech systems to treat and reuse wastewater in arid region. A key function of the wetland would be to provide additional N removal. To improve design criteria, a sequential model of nitrogen transformations (organic N! ammonium; ammonium!nitrate; nitrate!nitrogen gas) was successfully calibrated and verified for a wetland in Kingman, Arizona. A seq...

Six upflow anaerobic sludge blanket (UASB) reactors were concurrently operated for 146 d to examine the effects of calcium on the sludge granulation process during start-up. Introduction of Ca at concentrations from 150 to 300mg/l enhanced the biomass accumulation and granulation process. The calcium concentration in the granules was nearly proportional to the calcium concentration in the feed,...

A rigorous foundation is given for the logical formulation of process network synthesis on the basis of the combinatorial axioms of feasible processing networks. © 2000 Elsevier Science Ltd. All rights reserved.