On the Averaging of Equations of Change for Mass,Species Mass,Momentum and Energy – One-Dimensional Pipe Flows

The single-phase and multiphase Eulerian equations of change are derived by applying a suitable averaging procedure to the local instantaneous equations of change. In the present work, the local instantaneous equations of change for mass, species mass, momentum and energy are gross-scale averaged over the cross-sectional area. In particular, the internal energy equation is achieved by subtracting the kinetic energy equation from the total energy balance. Thus, two paths are to our disposal for deriving the cross-sectional averaged internal energy balance: (i) the averaged kinetic energy equation is subtracted from the averaged total energy equation, or (ii) the local instantaneous kinetic energy equation is subtracted from the local instantaneous energy equation and the resulting equation is averaged. The resulting Euler equations of change for internal energy are not identical for these two approaches. Approach (ii) is recommended because of its simplicity.     

BETaaS: A Platform for Development and Execution of Machine-to-Machine Applications in the Internet of Things

Wireless Personal Communications - The integration of everyday objects into the Internet represents the foundation of the forthcoming Internet of Things (IoT). Smart objects will be the building...     

Analysis of chiral amino acids in conventional and transgenic maize

In this work, a new chiral micellar electrokinetic chromatography with laser-induced fluorescence detection (chiral-MEKC-LIF) method is proposed to identify and quantify D- and L-amino acids in three lines of transgenic maize and their corresponding nontransgenic parental lines grown under identical conditions. The optimized procedure includes amino acids extraction, derivatization with FITC and chiral-MEKC-LIF separation in a background electrolyte composed of 100 mM sodium tetraborate, 80 mM SDS, and 20 mM beta-CD at pH 10.0. The D- and L-forms of Arg, Ser, Ala, Glu, and Asp, corresponding to the majority amino acids usually found in maize, are separated in less than 25 min with efficiencies up to 890,000 plates/m and high sensitivity (i.e., LODs as low as 160 nM were obtained for D-Arg for a signal-to-noise ratio of three), allowing the detection of 1% D-Arg in the presence of 99% of its opposite enantiomer. Using this method, different D-amino acids are detected in all investigated maize samples providing the reproducible quantification of the D-enantiomeric excess (% d-aa) for each amino acid calculated as % D-aa = 100D-aa/(D-aa + L-aa). Thus, significant differences were observed among the % d-aa values for the different conventional varieties (Aristis, Tietar, and PR33P66 maize) as could be expected from their natural variability. More interestingly, comparing each conventional maize with its corresponding transgenic line, very similar % D-aa values were obtained for one of the studied maize couples (Tietar vs Tietar-Bt) what could be presented as a new proof of their substantial equivalence. However, significant differences in the % d-aa values were observed for the other lines of maize studied. It is concluded that enantioselective procedures can open new perspectives in the study of transgenic organisms in order to corroborate (or not) the equivalence with their conventional counterparts.     

Application of liquid chromatography/quadrupole-linear Ion trap mass spectrometry and time-of-flight mass spectrometry to the determination of pharmaceuticals and related contaminants in wastewater

This paper describes an enhanced liquid chromatography-mass spectrometry (LC-MS) strategy for the analysis of a selected group of 56 organic pollutants in wastewater. This group comprises 38 pharmaceuticals and 10 of their most frequent metabolites, 6 pesticides, and 2 disinfectants. The LC-MS methodology applied is based in the use of a hybrid triple-quadrupole linear ion trap mass spectrometer (QTRAP) in combination with time-of-flight mass spectrometry (TOF-MS). The join application of both techniques provided very good results in terms of accurate quantification and unequivocal confirmation. Quantification was performed by LC-QTRAP-MS operating under selected reaction monitoring (SRM) mode in both positive and negative electrospray ionization. Unequivocal identification was provided by the acquisition of three SRM transitions per compound in most of the cases and by LC-TOF-MS analysis, which allows obtaining accurate mass measurements of the identified compounds with errors lower than 2 ppm. Additionally, the use of TOF-MS permits retrospective analysis, since the full spectrum is recorded at all times with a high sensitivity. Thus, review of recorded chromatograms looking for new compounds or transformation products suspected to be present in the samples is feasible allowing one to increase the scope of the method along the monitoring program. The analytical performance of the quantitative LC-QTRAP-MS method was evaluated in effluent wastewater samples. Linearity of response over 3 orders of magnitude was demonstrated for most compounds (R(2) > 0.99). Method limits of detection were between 0.04 and 50 ng L(-1). Finally, the methodology was successfully applied to a monitoring study intended to characterize wastewater effluents of six sewage treatment plants in Spain. The presence of most of compounds was detected at concentrations ranging from 9 ng L(-1) (atrazine) to 15 microg L(-1) (paraxanthine).     

Ultra-widely tunable long-period holey-fiber grating by the use of mechanical pressure

We report an ultra-widely tunable long-period holey-fiber grating, which combines the wide-range single-mode behavior and transverse strain sensitivity of the holey fibers with the advantages of mechanically induced long-period fiber gratings. We obtain a versatile widely tunable long-period holey-fiber grating with attractive transmission spectral characteristics for optical communications, fiber-based amplifiers, and lasers. The mechanically induced long-period holey-fiber grating shows a continuous tuning range over 500 nm, more than 12 dB depth notches with less than 0.75 dB out-of-band losses, and bandwidth control from 10 to 40 nm.     

Remote monitoring of multi-gas mixtures by passive standoff Fourier transform infrared radiometry

The passive remote monitoring of multi-gas mixtures was experimentally investigated using Fourier transform infrared (FT-IR) radiometry. The spectral radiance data were collected using a dual-port radiometrically balanced interferometer for a variety of multi-gas plumes at a standoff distance of 60 m. Two basic sets of mixtures were studied. The first set corresponded to mixtures consisting of three gases with no overlapping spectral bands (C(2)H(2), C(2)H(4), and R14). The second set corresponded to mixtures of three gases having significant spectral overlap (C(2)H(4), R114, and R134a). For each mixture the flow rates of individual constituents were adjusted to yield specific constituent optical-density (CL) ratios. These ratios were compared to the optical-density ratios retrieved from the measured infrared radiance spectra. Results of this study indicated that for both sets of multi-gas mixtures the optical-density ratios retrieved by the passive remote monitoring technique were in good agreement with those derived from the release flow rates, provided that a simple correction scheme was introduced to compensate for the limited accuracy of the fast radiance model implemented in the monitoring algorithm.     

Monte Carlo neutron doses estimations inside a PET cyclotron vault room

Neutron organ equivalent doses, effective doses and dose equivalents received inside a positron emission tomography vault room in a maximum credible accident have been estimated with the Monte Carlo code MCNPX. While an operator was inside the vault room of a Cyclone 18/9 IBA cyclotron, this was producing (18)F with 30 muA proton current in the target and the operator had to activate a stopped emergency device placed on the wall. MC simulation of the cyclotron vault were carried out to estimate the organ and tissue equivalent doses in a mathematical male mannequin simulating the operator facing the wall on which the emergency device is placed. Doses were calculated at two emergency devices for each one of the two targets of the cyclotron, which were able to produce (18)F. The maximum effective dose in the mannequin was 6.70 Sv/h and the maximum organ equivalent dose was 18.47 Sv/h in spleen.     

A comparative study of the adsorption of humic acid, fulvic acid and phenol onto Bacillus subtilis and activated sludge

The adsorption of humic acid and fulvic acid onto Bacillus subtilis cells and activated sludge biomass was studied as a function of pH and incubation time. The adsorption of humic and fulvic acids was strongly pH-dependent and followed the same trend on both surfaces, increasing in a sigmoidal way with decreasing pH over the 2-10 pH range. This behaviour is explained in terms of hydrophobic interactions between the uncharged biomass and the uncharged humic and fulvic acids. In contrast, the adsorption of phenol onto B. subtilis cells and activated sludge biomass showed in both cases an optimum pH at around 7.0. This optimum value may be interpreted in terms of a combination of hydrophobic interactions and hydrogen bonds between undissociated phenol and polar groups on the cell walls. Kinetic studies on the adsorption of humic acid, fulvic acid and phenol onto B. subtilis cells and sludge biomass pointed to a rapid uptake of the substances, with an equilibrium time of about 30 min. In all cases, the kinetic curves were acceptably fitted by non-linear regression to an exponential function, suggesting a first-order kinetic phenomenon. The specific adsorption values collected at optimum pH revealed that with the materials used in this work both B. subtilis and activated sludge follow the same adsorption trend: humic>fulvic>phenol. The lower adsorption of fulvic acid as compared with humic acid may be explained in terms of its lower hydrophobicity rather than its lower molecular size. On comparing the specific adsorption values of activated sludge versus B. subtilis, similar but lower figures were found for the three organic compounds studied. This similar behaviour suggests that both types of biomass base their adsorption capacity on the general characteristics of the bacterial cell wall, and the lower adsorption by the sludge would be due to a lower specific area due to clustering of the cells. This is remarkable, since sludge is a heterogeneous and cheap material in comparison with cultured bacterial cells.     

EVA Nanocomposites Elaborated with Bentonite Organo‐Modified by Wet and Semi‐Wet Methods

EVA copolymer/organoclay nanocomposites were prepared using melt‐compounding. Organoclays were obtained using wet and semi‐wet modification methods. These methods enable us to obtain organoclays with adequate modifier incorporation, but organoclays with a homogeneous and narrow agglomeration size distribution were obtained only with the wet method. TS and EB were higher for nanocomposites obtained with organoclays prepared using the wet method. Analysis of Limiting Oxygen Index, UL94 test and Cone Calorimeter test showed that the retardant properties of nanocomposites were also influenced by the kind of modifiers and the modification method.

     

Indicators of European public research in hydrogen and fuel cells—An input–output analysis

A prerequisite of any coordinated research activity is a comparison of the current status of research in the countries in question and a means to monitor the progress in particular sectors. Analysis of indicators of research in different countries allows comparison of the research undertaken. This paper compares input and output indicators of public research in hydrogen and fuel cells (H&FC) both within Europe and between Europe and the US, Japan and China. Overall the combined public H&FC research budget for the EU25 countries, associated states and accession countries was €276M$€276\mathrm{M}$ in 2005, slightly higher than in the US, but lower than in Japan. An analysis of research outputs indicates that European competitive advantage is being lost to China and the US. Greater and more effective research coordination as well as more targeted allocation of research funds are proposed as potential solutions.