Quantification of pathogenic microorganisms and microbial indicators in three wastewater reclamation and managed aquifer recharge facilities in Europe

Managed Aquifer Recharge (MAR) is becoming an attractive option for water storage in water reuse processes as it provides an additional treatment barrier to improve recharged water quality and buffers seasonal variations of water supply and demand. To achieve a better understanding about the level of pathogenic microorganisms and their relation with microbial indicators in these systems, five waterborne pathogens and four microbial indicators were monitored over one year in three European MAR sites operated with reclaimed wastewater. Giardia and Cryptosporidium (oo)cysts were found in 63.2 and 36.7% of the samples respectively. Salmonella spp. and helminth eggs were more rarely detected (16.3% and 12.5% of the samples respectively) and Campylobacter cells were only found in 2% of samples. At the Belgian site advanced tertiary treatment technology prior to soil aquifer treatment (SAT) produced effluent of drinking water quality, with no presence of the analysed pathogens. At the Spanish and Italian sites amelioration of microbiological water quality was observed between the MAR injectant and the recovered water. In particular Giardia levels decreased from 0.24-6.14 cysts/L to 0-0.01 cysts/L and from 0.4-6.2 cysts/L to 0-0.07 cysts/L in the Spanish and Italian sites respectively. Salmonella gene copies and Giardia cysts were however found in the water for final use and/or the recovered groundwater water at the two sites. Significant positive Spearman correlations (p < 0.05, r_s range: 0.45-0.95) were obtained, in all the three sites, between Giardia cysts and the most resistant microbial markers, Clostridium spores and bacteriophages.     

Chain extension and branching of poly(ethylene terephthalate) (PET) with di- and multifunctional epoxy or isocyanate additives: An experimental and modelling study

The effect of two difunctional chain extenders, 1,6-diisocyanatohexane (NCO) and 1,4-butanediol diglycidyl ether (EPOX), in the reactive melt-processing of a post-consumer poly(ethylene terephthalate) (r-PET) was investigated. The torque evolution during processing in a batch mixer and the molecular weight of the chain-extended r-PET, as determined by SEC analysis, were comparatively evaluated. A simple mathematical model proposed here was used to fit the obtained molecular weights. Two polyfunctional chain extenders, poly(phenyl isocyanate-co-formaldehyde) (P-NCO) and a styrene-acrylate copolymer bearing epoxide groups (P-EPOX), were also used and their reactivity was compared with that of the difunctional ones by analysing torque and melt flow rate data. The different reactivity of the two functional groups and the structure of the final polymer (either linear or branched depending on the type of chain extender) affect both crystallization behaviour and tensile properties of the modified r-PET. Fine tuning of the latter properties by suitable chain extender(s) selection and formulation is anticipated.     

Aqueous atmospheric chemistry: formation of 2,4-dinitrophenol upon nitration of 2-nitrophenol and 4-nitrophenol in solution

Field studies have shown that the powerful phytotoxic agent 2,4-dinitrophenol is very likely to form in the atmospheric aqueous phase upon nitration of 2-nitrophenol or 4-nitrophenol. However, until now, the nitration pathway and the relative importance of the two mononitrophenols as sources of 2,4-dinitrophenol were not known. The present study shows that 2,4-dinitrophenol formation from mononitrophenols can take place upon photolysis and photooxidation of nitrite/nitrous acid (NO2-/HONO) and that nitrogen dioxide plays a key role in the process. A possible pathway might be the reaction between light-excited mononitrophenols (both 2- and 4-isomers) and nitrogen dioxide, in the presence of oxygen. As an alternative, nitration might involve *NO3 + *NO2. Possible sources of nitrogen dioxide in the atmospheric aqueous phase are dissolution from the gas phase and oxidation of NO2-. In the latter case, however, it is necessary that NO2- oxidation is faster than the oxidation of mononitrophenols. This would happen, for instance, in the presence of hematite under irradiation. Radiation absorption and scattering by hematite would also inhibit the direct photolysis of nitrophenols. The formation rate and the yield of 2,4-dinitrophenol are slightly higher when starting from 2-nitrophenol than those from 4-nitrophenol, but they are compensated by the higher concentration of 4-nitrophenol in the atmospheric aqueous phase.     

Engineering evolution of the FAST machine

FAST (Fusion Advanced Studies Torus) is a proposal for a Satellite Facility which can contribute the rapid exploitation of ITER and prepare ITER and DEMO regimes of operation, as well as exploit innovative plasma facing component systems for DEMO. FAST is a compact (Ro = 1.82 m, a = 0.64 m, triangularity δ = 0.4) and cost effective machine able to investigate, with integration capability, non linear dynamics effects of alpha particle behaviour in burning plasmas. FAST operates in high performance H-mode (B_T up to 8.5 T; I_P up to 8 MA), as well as in advanced tokamak mode (I_P = 3 MA), and in full non inductive current mode (I_P = 2 MA). Helium gas at 30 K is used for cooling the resistive copper magnets. This allows for a pulse duration up to 170 s at 3 MA/3.5 T. The vacuum vessel (VV), segmented into 20-degree modules, is capable to accommodate a 40 MW RF power system. The machine has been designed to house a 10 MW Negative Neutral Beam Injection (NNBI) system. Tungsten (W) or liquid lithium (L-Li) have been chosen as the divertor plate materials, and argon or neon as the impurities to be injected for mitigating the thermal loads.     

Alkoxide-based precursors for direct drawing of metal oxide micro- and nanofibres

The invention of electrospinning has solved the problem of producing micro- and nanoscaled metal oxide fibres in bulk quantities. However, until now no methods have been available for preparing a single nanofibre of a metal oxide. In this work, the direct drawing method was successfully applied to produce metal oxide (SnO₂, TiO₂, ZrO₂, HfO₂ and CeO₂) fibres with a high aspect ratio (up to 10 000) and a diameter as small as 200 nm. The sol–gel processing includes consumption of precursors obtained from alkoxides by aqueous or non-aqueous polymerization. Shear thinning of the precursors enables pulling a material into a fibre. This rheological behaviour can be explained by sliding of particles owing to external forces. Transmission (propagation) of light along microscaled fibres and their excellent surface morphology suggest that metal oxide nanofibres can be directly drawn from sol precursors for use in integrated photonic systems.     

Dipyridamole stress echocardiography in diagnosis and prognosis of hemodialysis patients with asymptomatic coronary disease

The prevalence of coronary artery disease (CAD) is high in hemodialysis (HD) patients. The aim of the study was to assess the diagnostic and prognostic value of dipyridamole stress echocardiography (DSE) in nondiabetic HD patients without signs or symptoms of CAD. In 51 out of 158 evaluated HD patients (21 females, age 67 [33–85] years, HD duration 38 [9–271] months), resting echocardiography and DSE were performed. Exclusion criteria were known CAD, diabetes mellitus, and pulmonary and oncologic pathologies. Logistic regression analysis was carried out to identify predictors of abnormal DSE response, while Cox regression analysis was performed to determine variables associated with total and cardiovascular mortality, after 43.3 (11–60) months of follow‐up. Seven patients (14%) showed a positive response to DSE (DSE+). In 5/7, CAD was documented by angiography: All of them underwent coronary revascularization. DSE+ patients had significantly smaller body mass index than patients with a negative response (DSE‐): 21.7 ± 1.9 vs. 25.1 ± 3.4 kg/m² (p = 0.018). During follow‐up, 16 (31%) patients died. Older age hazard ratio [HR = 1.07; confidence interval (CI) = 1.01–1.12; p = 0.02] and higher plasma phosphate levels (HR = 10.41; CI = 2.30–47.17; p < 0.01) were predictors of total mortality. Male gender (HR = 22.7; CI = 1.45–354.4; p = 0.03), older age (HR = 1.24; CI = 1.03–1.50; p = 0.02), longer HD duration (HR = 1.13; CI = 1.01–1.26; p = 0.04), and positive response to DSE (HR = 5.82; CI = 1.04–32.65; p = 0.04) were associated with cardiovascular mortality. Ten percent of asymptomatic HD patients had significant CAD, but timely diagnosis did not seem to improve their prognosis. Total survival was associated with age and higher levels of plasma phosphate, while male gender, older age, longer HD duration, and DSE+ were predictors of cardiovascular mortality.     

Fe(lll)-enhanced sonochemical degradation of methylene blue in aqueous solution

The sonochemical degradation rate of Methylene Blue (MB) is markedly increased in the presence of Fe(Ill), a rather inexpensive reagent for the application of sonochemistry to wastewater treatment. The effect of Fe(lll) is due to a sonochemically induced Fenton reaction, where both reactants (Fe(ll) and H2O2) are sonochemically synthesized. Hydroperoxide/superoxide, generated upon sonochemical processes in aerated solution, is a key species involved in both Fe(lll) reduction to Fe(ll) and in the production of H2O2. The Fenton reaction between Fe(ll) and H2O2 then produces hydroxyl radicals, enhancing the degradation of MB. A further enhancement of the degradation of the substrate in the presence of Fe(lll) takes place upon addition of H2O2, which is likely to favor the Fenton process. Interestingly, H2O2 alone, in the absence of Fe(lll), has a very limited effect on the sonochemical degradation rate.     

Molten Carbonate Fuel Cell electrochemistry modelling

A Fuel Cell (FC) is an electrochemical device which produces electric energy in DC. In order to support design control for the electrical system connected to it, it is necessary to work out a suitable representation of the fast dynamics involved. Therefore, in this work, a mathematical model, based on first principles and including both dynamical equations and algebraic relations, is described for electrochemical reactions, with the related formation of potential differences and anion and cation accumulation phenomena, in a Molten Carbonate Fuel Cell (MCFC). The model is formally consistent and it has been validated against experimental results, such as steady-state power and voltage versus current curves.     

Combining time series prediction models using genetic algorithm to autoscaling Web applications hosted in the cloud infrastructure

In a cloud computing environment, companies have the ability to allocate resources according to demand. However, there is a delay that may take minutes between the request for a new resource and it being ready for using. This causes the reactive techniques, which request a new resource only when the system reaches a certain load threshold, to be not suitable for the resource allocation process. To address this problem, it is necessary to predict requests that arrive at the system in the next period of time to allocate the necessary resources, before the system becomes overloaded. There are several time series forecasting models to calculate the workload predictions based on history of monitoring data. However, it is difficult to know which is the best time series forecasting model to be used in each case. The work becomes even more complicated when the user does not have much historical data to be analyzed. Most related work considers only single methods to evaluate the results of the forecast. Other works propose an approach that selects suitable forecasting methods for a given context. But in this case, it is necessary to have a significant amount of data to train the classifier. Moreover, the best solution may not be a specific model, but rather a combination of models. In this paper we propose an adaptive prediction method using genetic algorithms to combine time series forecasting models. Our method does not require a previous phase of training, because it constantly adapts the extent to which the data are coming. To evaluate our proposal, we use three logs extracted from real Web servers. The results show that our proposal often brings the best result and is generic enough to adapt to various types of time series.