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Ghaniyari-Benis S.,Sharif University of Technology | Martin A.,Campus Universitario Of Rabanales | Borja R.,CSIC - Instituto de la Grasa
Process Biochemistry | Year: 2010

A modelling study on the anaerobic digestion process of a synthetic medium-strength wastewater containing molasses as a carbon source was carried out at different influent conditions. The digestion was conducted in a laboratory-scale hybrid anaerobic baffled reactor with three compartments and a working volume of 54L, which operated at mesophilic temperature (35°C). Two different kinetic models (one model was based on completely stirred tank reactors (CSTR) in series and the other an axial diffusion or dispersion model typical of deviations of plug-flow reactors), were assessed and compared to simulate the organic matter removal or fractional conversion. The kinetic constant (k) obtained by using the CSTR in series model was 0.60±0.07h-1, while the kinetic parameter achieved with the dispersion model was 0.67±0.06h-1, the dispersion coefficient (D) being 46. The flow pattern observed in the reactor studied was intermediate between plug-flow and CSTR in series systems, although the plug-flow system was somewhat predominant. The dispersion model allowed for a better fit of the experimental results of fractional conversions with deviations lower than 8% between the experimental and theoretical values. By contrast, the CSTR in series model predicted the behaviour of the reactor somewhat less accurately showing deviations lower than 10% between the experimental and theoretical values of the fractional conversion. © 2010 Elsevier Ltd. Source


Gomez Alvarez E.,CNRS Chemistry Laboratory | Gligorovski S.,CNRS Chemistry Laboratory | Wortham H.,CNRS Chemistry Laboratory | Cases M.V.,Campus Universitario Of Rabanales
Talanta | Year: 2012

A characterisation of a system designed for active sampling of gaseous compounds with Solid Phase Microextraction (SPME) fibres is described. This form of sampling is useful to automate sampling while considerably reducing the sampling times. However, the efficiency of this form of sampling is also prone to be affected by certain undesirable effects such as fibre saturation, competition or displacement effects between analytes, to which particular attention should be paid especially at high flow rates. Yet, the effect of different parameters on the quantitivity of the results has not been evaluated. For this reason, in this study a careful characterisation of the influence of the parameters involved in active sampling SPME has been performed. A versatile experimental set-up has been designed to test the influence of air velocities and fluid regime on the quantitivity and reproducibility of the results. The mathematical model applied to the calculation of physical parameters at the sampling points takes into consideration the inherent characteristics of gases, distinctive from liquids and makes use of easily determined experimental variables as initial/boundary conditions to get the model started. The studies were carried out in the high-volume outdoor environmental chambers, EUPHORE. The sample subjected to study was a mixture of three aldehydes: pentanal, hexanal and heptanal and the determination methodology was O-(2,3,4,5,6- pentafluorobenzyl)-hydroxylamine hydrochloride (PFBHA) on-fibre derivatisation. The present work proves that the determination procedure is quantitative and sensitive, independent from experimental conditions: temperature, relative humidity or ozone levels. With our methodology, the influence on adsorption of three inter-related variables, i.e., air velocity, flow rate and Reynolds numbers can be separated, since a change can be exerted in one of them while keeping the others constant. © 2011 Elsevier B.V. All rights reserved. Source


Napp S.,Autonomous University of Barcelona | Garcia-Bocanegra I.,Campus Universitario Of Rabanales | Pages N.,Autonomous University of Barcelona | Allepuz A.,Autonomous University of Barcelona | And 2 more authors.
Medical and Veterinary Entomology | Year: 2013

The importation of infected hosts and the arrival of windborne infected Culicoides (Diptera: Ceratopogonidae) were considered unlikely mechanisms for bluetongue virus (BTV) incursion into a BTV-free area during the recent BTV serotype 8 (BTV-8) epidemic in northern Europe. Therefore, alternative mechanisms need to be considered. Air, sea and land transport networks continue to expand, and an important consequence of this is vector-borne pathogen importation. One important aspect of bluetongue (BT) epidemiology not yet addressed is the potential movement of infected Culicoides via transport and trade networks. Therefore, a risk assessment model was constructed to assess the probability of a BTV outbreak as a consequence of the introduction of Culicoides via these networks. The model was applied to calculate the risk for a BTV-8 epidemic in Spain in 2007 caused by the introduction of Culicoides from affected northern European countries. The mean weighted annual risk for an outbreak caused by transportation of a single vector from an affected northern European country varied from 1.8 × 10-7 to 3.0 × 10-13, with the highest risks associated with Culicoides imported from Belgium, the Netherlands, Germany and France. For this mechanism to pose a significant risk to BTV-free countries, a large number of vectors would have to be transported. © 2012 The Authors. Medical and Veterinary Entomology © 2012 The Royal Entomological Society. Source


Ghaniyari-Benis S.,Sharif University of Technology | Martin A.,Campus Universitario Of Rabanales | Borja R.,CSIC - Instituto de la Grasa | Martin M.A.,Campus Universitario Of Rabanales | Hedayat N.,University of Tehran
Bioprocess and Biosystems Engineering | Year: 2012

A modelling of the anaerobic digestion process of molasses was conducted in a 70-L multistage anaerobic biofilm reactor or hybrid anaerobic baffled reactor with six compartments at an operating temperature of 26 °C. Five hydraulic retention times (6, 16, 24, 72 and 120 h) were studied at a constant influent COD concentration of 10,000 mg/L. Two different kinetic models (one was based on a dispersion model with first-order kinetics for substrate consumption and the other based on a modification of the Young equation) were evaluated and compared to predict the organic matter removal efficiency or fractional conversion. The first-order kinetic constant obtained with the dispersion model was 0.28 h -1, the Peclet dispersion number being 45, with a mean relative error of 2%. The model based on the Young equation predicted the behaviour of the reactor more accurately showing deviations lower than 10% between the theoretical and experimental values of the fractional conversion, the mean relative error being 0.9% in this case. © 2011 Springer-Verlag. Source


Dez C.M.,Campus Universitario Of Rabanales | Dez C.M.,University of California at Irvine | Trujillo I.,Campus Universitario Of Rabanales | Barrio E.,University of Valencia | And 3 more authors.
Annals of Botany | Year: 2011

Background and AimsGenetic characterization and phylogenetic analysis of the oldest trees could be a powerful tool both for germplasm collection and for understanding the earliest origins of clonally propagated fruit crops. The olive tree (Olea europaea L.) is a suitable model to study the origin of cultivars due to its long lifespan, resulting in the existence of both centennial and millennial trees across the Mediterranean Basin.MethodsThe genetic identity and diversity as well as the phylogenetic relationships among the oldest wild and cultivated olives of southern Spain were evaluated by analysing simple sequence repeat markers. Samples from both the canopy and the roots of each tree were analysed to distinguish which trees were self-rooted and which were grafted. The ancient olives were also put into chronological order to infer the antiquity of traditional olive cultivars.Key ResultsOnly 9·6 out of 104 a priori cultivated ancient genotypes matched current olive cultivars. The percentage of unidentified genotypes was higher among the oldest olives, which could be because they belong to ancient unknown cultivars or because of possible intra-cultivar variability. Comparing the observed patterns of genetic variation made it possible to distinguish which trees were grafted onto putative wild olives.ConclusionsThis study of ancient olives has been fruitful both for germplasm collection and for enlarging our knowledge about olive domestication. The findings suggest that grafting pre-existing wild olives with olive cultivars was linked to the beginnings of olive growing. Additionally, the low number of genotypes identified in current cultivars points out that the ancient olives from southern Spain constitute a priceless reservoir of genetic diversity. © The Author 2011. Source

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