TOPYDE: A Tool for Physical Database Design

We describe a tool for physical database design based on a combination of theoretical and pragmatic approaches. The tool takes as input a relational schema, the workload defined on the schema, and some additional database characteristics and produces as output a physical schema. For the time being, the tool is tuned towards Ingres

Dynamic consolidation measurements in a well field using fiber bragg grating sensors

Currently available groundwater flow prediction tools and methods are limited by insufficient spatial resolution of subsurface data and the unknown local heterogeneity. In this field study, fiber Bragg grating (FBG) sensors were installed in an extraction well field to investigate its potential to measure groundwater flow velocity. Reference in-situ pore pressure and temperature measurements were used to identify possible sources of FBG responses. FBG strain sensors were able to detect soil consolidation caused by groundwater extraction from 250 m distance. The results show that FBG responses were influenced by interface friction between soil and FBG packaging. FBG packaging slipped in soil and the effect was more pronounced during higher groundwater flow around a nearby well. These FBG fibers could be applied for indirect flow monitoring that does not require any tracer and provide real-time and long-term data during regular operation of extraction wells

Polylectrolyte- versus membrane-coated electrodes for energy production by Capmix salinity exchange methods

La versión final publicada se puede encontrar en: Journal of Power Sources, 302(20): 387-393 (2016). http://dx.doi.org/10.1016/j.jpowsour.2015.10.076In this paper we analyze the energy and power achievable by means of a re- cently proposed salinity gradient technique for energy production. The method, denominated soft electrode or SE, is based on the potential di erence that can be generated between two porous electrodes coated with cationic and anionic polyelectrolytes. It is related to the Capacitive Donnan Potential (CDP) tech- nique, where the electrical potential variations are mostly related to the Donnan potential, of ion-selective membranes in the case of CDP, and of the polyelec- trolyte coating in SE. It is found that although SE is comparable to CDP in terms of energy production, it presents slower rates of voltage change, and lower achieved power. The separate analysis of the response of positively and neg- atively coated electrodes shows that the latter produces most of the voltage rise and also of the response delay. These results, together with electrokinetic techniques, give an idea on how the two types of polyelectrolytes adsorb on the carbon surface and a ect di erently the di usion layer. It is possible to suggest that the SE technique is a promising one, and it may overcome the drawbacks associated to the use of membranes in CDP.MINECO FIS2013-47666-C3-1-RJunta de Andalucía, PE2012-FQM0694European Union 7th Framework Programme (FP7/2007–2013) under agreement No. 25686

Quantification of the Retention and Disassembly of Virus Particles by a PEI-Functionalized Microfiltration Membrane

[Image: see text] Monitoring the performance of polymer-functionalized surfaces that aim at removing and inactivating viruses is typically labor-intensive and time-consuming. This hampers the development and optimization of such surfaces. Here we present experiments of low complexity that can be used to characterize and quantify the antiviral properties of polymer-functionalized surfaces. We showcase our approach on polyethylenimine (PEI)-coated poly(ether sulfone) (PES) microfiltration membranes. We use a fluorescently labeled model virus to quantify both virus removal and inactivation. We directly quantify the log removal of intact viruses by this membrane using single particle counting. Additionally, we exploit the change in photophysical properties upon disassembly of the virus to show that viruses are inactivated by the PEI coating. Although only a small fraction of intact viruses can pass the membrane, a considerable fraction of inactivated, disassembled viruses are found in the filtrate. Fluorescence microscopy experiments show that most of the viruses left behind on the microfiltration membrane are in the inactivated, disassembled state. Combined, our fluorescence microscopy and spectroscopy experiments show that not only does the model virus adsorb to the PEI coating on the membrane but also the interaction with PEI results in the disassembly of the virus capsid

An introduction to superhydrophobicity

This paper is derived from a training session prepared for COST P21. It is intended as an introduction to superhydrophobicity to scientists who may not work in this area of physics or to students. Superhydrophobicity is an effect where roughness and hydrophobicity combine to generate unusually hydrophobic surfaces, causing water to bounce and roll off as if it were mercury and is used by plants and animals to repel water, stay clean and sometimes even to breathe. The effect is also known as The Lotus Effect® and Ultrahydrophobicity. In this paper we introduce many of the theories used, some of the methods used to generate surfaces and then describe some of the implications of the effect

Effect of Solution Composition on the Energy Production by Capacitive Mixing in Membrane-Electrode Assembly

The final edited version of the paper can be found at: http://pubs.acs.org/articlesonrequest/AOR-c9UMxSzGY3eiU5SENNgT The complete citation is: Ahualli, S.; et al. Effect of Solution Composition on the Energy Production by Capacitive Mixing in Membrane-Electrode Assembly. Journal of Physical Chemistry, 118(29): 15590-15599 (2014). DOI:10.1021/jp504461mOpen access in the Journal on May 26, 2015In this work we consider the extent to which the presence of multi-valent ions in solution modifies the equilibrium and dynamics of the energy production in a capacitive cell built with ion-exchange membranes in contact with high surface area electrodes. The cell potential in open circuit (OCV) is controlled by the difference between both membrane potentials, simulated as constant volume charge regions. A theoretical model is elaborated for steady state OCV, first in the case of monovalent solutions, as a reference. This is compared to the results in multi-ionic systems, containing divalent cations in concentrations similar to those in real sea water. It is found that the OCV is reduced by about 25 % (as compared to the results in pure NaCl solutions) due to the presence of the divalent ions, even in low concentrations. Interestingly, this can be related to the “uphill” transport of such ions against their concentration gradients. On the contrary, their effect on the dynamics of the cell potential is negligible in the case of highly charged membranes. The comparison between model predictions and experimental results shows a very satisfactory agreement, and gives clues for the practical application of these recently introduced energy production methods.The research leading to these results received funding from the European Union 7th Framework Programme (FP7/2007-2013) under agreement No. 256868. Further financial support from Junta de Andalucia, Spain (PE2012-FQM 694) is also acknowledged. One of us, M.M.F., received financial support throughan FPU grant from the Universityof Granada

Effect of Ultrasound on Calcium Carbonate Crystallization

Scaling comprises the formation of hard mineral deposits on process or membrane equipment and calcium carbonate is the most common scaling salt. Especially in reverse osmosis (RO) membrane systems, scale formation has always been a serious limitation, causing flux decline, membrane degradation, loss of production and elevated operating costs. In this work a novel concept is proposed for the prediction of scale formation tendency. By enhancing the crystallization (kinetics) locally and monitoring the process itself, scaling can be predicted accurately before it occurs in the bulk solution. This will result in better scaling risk assessment, improving chemical dosage (preventing overdosing) and prevent the necessity of cleaning or membrane replacement. Ultrasound is selected as possible method for crystallization enhancement. Consequently, the topic of this research is the effect of ultrasound on crystallization of calcium carbonate.BiotechnologyApplied Science