Catalytic oxidation of emissions in combustion systems for forest biomass, using catalysts with TiO2 support

A study was made of the catalytic oxidation of a model mixture of effluents from forest biomass combustion equipment, consisting principally of methane (CH4), naphthalene (C10H8), carbon monoxide (CO) and oxygen-poor air (10% O2, balance N2), in a laboratory reactor, using MeOx/TiO2 catalysts (Me = Fe, Cu or Mn), prepared using incipient wetness impregnation. It was observed that the addition of metal oxides to the TiO2 increases catalytic activity in the combustion of all the contaminants present in the model effluent (CH 4, C10H8 and CO). The catalysts were characterised using the following techniques: SBET, XRD, DTG/DTA and TPD-NH 3; and from these it was observed that the support presented only the anatase phase in all the catalysts, despite having been subjected to temperatures in excess of 1.000 K during combustion. The highest acidity among all the solids tested, measured by TPD-NH3, was obtained for the FeOx/TiO2 catalysts, which were also those which showed the greatest catalytic activity. This high level of activity may be related to the formation of isolated metallic phases; i.e. hematite (Fe2O3), which would be the active phase in the combustion of C10H8 and CH4. On the other hand, with to respect to the 5 % wt. values of Me/TiO2 (Me: Fe, Cu y Mn) catalysts, the CuO/TiO2 catalyst shows greater activity than Fe2O3/TiO2 and MnOx/TiO2 for the oxidation of CO, which would be related to the formation of CuO on the TiO2 surface. The formation of mixed phases between the metals and the TiO2 was not observed. The SBET of the most active catalyst, Fe2O3/TiO2 (where Fe is 5% w/w in value), was not subject to any changes during the reaction

All-Dielectric Rod-Type Metamaterials at Optical Frequencies

Light propagation in all-dielectric rod-type metamaterials is studied theoretically. The electric and magnetic dipole moments of the rods are derived analytically in the long-wavelength limit. The effective permittivity and permeability of a square lattice of rods are calculated by homogenizing the corresponding array of dipoles. The role of dipole resonances in the optical properties of the rod array is interpreted. This structure is found to exhibit a true left-handed behavior, confirming previous experiments [L. Peng \textit{et al.}, Phys. Rev. Lett. \textbf{98}, 157403 (2007)]. A scaling analysis shows that this effect holds at optical frequencies and can be obtained by using rods made, for example, of silicon.Comment: 10 pages, 4 figures. The title has been shortened; Figs. 1, 2 and 3 have been modified; Eq. 4 has been corrected (sign error); A few sentences have been added/rewritte

General unit-disk representation for periodic multilayers

We suggest a geometrical framework to discuss periodic layered structures in the unit disk. The band gaps appear when the point representing the system approaches the unit circle. We show that the trace of the matrix describing the basic period allows for a classification in three families of orbits with quite different properties. The laws of convergence of the iterates to the unit circle can be then considered as universal features of the reflection.Comment: 3 pages, 2 eps-figures. To be published in Optics Letter

Preferential oxidation of CO over Au/CuOx-CeO2 catalyst in microstructured reactors studied through CFD simulations

A computational fluid dynamics (CFD) simulation study of the preferential oxidation of CO (CO-PROX) in microstructured reactors consisting in square and semicircular microchannels coated with anAu/CuOx¿CeO2catalyst is presented. The CO content of the feed stream was set at 1 vol.%. A parametricsensitivity analysis has been performed under isothermal conditions revealing that an optimal reactiontemperature exists that leads to a minimum CO content at the microreactor exit. The influence of thespace velocity, CO2concentration and oxygen-to-CO molar ratio in the feed stream (), catalyst loading,and microchannel characteristic dimension (d) on the microreactor performance has been investigated.Under suitable conditions, the CO concentration can be reduced below 10 ppm at relatively low tem-peratures within the 155¿175¿C range. A negative effect of the increase of d from 0.35 mm to 2.8 mmon the CO removal efficiency has been found and attributed to a more detrimental effect of the masstransport limitations on the oxidation of CO than that of H2. Non-isothermal CFD simulations have beenperformed to investigate the cooling of the CO-PROX reactor with air or a fuel cell anode off gas surrogatein parallel microchannels. Due to the very rapid heat transfer allowed by the microreactor and the stronginfluence of the reaction temperature on the exit CO concentration, a careful control of the coolant flowrate and inlet temperature is required for proper reactor operation. The microreactor behavior is virtuallyisothermal.Peer Reviewe

Impact of the new handling recommendations for hazardous drugs in a hospital pharmacy service

Objective: To describe the actions taken by the Pharmacy Unit in a tertiary hospital in order to adapt to the recommendations established by NIOSH 2014 for handling Hazardous Drugs. Method: A retrospective observational study. A list was prepared including all hazardous drugs according to NIOSH 2014 that were available at the hospital as marketed or foreign drugs, or used in clinical trials, and there was a review of the processes of acquisition, repackaging, preparation, circuits, organizational, dispensing and identification. Results: After the analysis, a report including all needs was prepared and sent to the Hospital Management. Any relevant information about the handling and administration of hazardous drugs was included in the prescription computer program. There were changes in the acquisition process of two drugs, in order to avoid splitting and multi-dose formulations. An alternative or improvement was found for 35 253 of the 75 779 units of hazardous drugs repackaged in one year. The Pharmacy Unit took over the preparation of four non-sterile medications, as well as the preparation of all sterile parenteral medications included in Lists 1 and 2 that were not previously prepared there, as well as one from List 3. Information was also included about the preparation processes of Magistral Formulations that involved hazardous drugs from Lists 2 or 3

Potential of red and white whole grain sorghum flour in gluten-free breadmaking: a study on consumer acceptability.

31st EFFoST

The second flight of the SUNRISE balloon-borne solar observatory: overview of instrument updates, the flight, the data and first results

The SUNRISE balloon-borne solar observatory, consisting of a 1~m aperture telescope that provided a stabilized image to a UV filter imager and an imaging vector polarimeter, carried out its second science flight in June 2013. It provided observations of parts of active regions at high spatial resolution, including the first high-resolution images in the Mg~{\sc ii}~k line. The obtained data are of very high quality, with the best UV images reaching the diffraction limit of the telescope at 3000~\AA\ after Multi-Frame Blind Deconvolution reconstruction accounting for phase-diversity information. Here a brief update is given of the instruments and the data reduction techniques, which includes an inversion of the polarimetric data. Mainly those aspects that evolved compared with the first flight are described. A tabular overview of the observations is given. In addition, an example time series of a part of the emerging active region NOAA AR~11768 observed relatively close to disk centre is described and discussed in some detail. The observations cover the pores in the trailing polarity of the active region, as well as the polarity inversion line where flux emergence was ongoing and a small flare-like brightening occurred in the course of the time series. The pores are found to contain magnetic field strengths ranging up to 2500~G and, while large pores are clearly darker and cooler than the quiet Sun in all layers of the photosphere, the temperature and brightness of small pores approach or even exceed those of the quiet Sun in the upper photosphere.Comment: Accepted for publication in The Astrophysical Journa

Constructal Design of Elliptical Conduits for Cooling of Gas Turbine Blades with External Thermal Barrier Coating

Gas turbines (GTs) are thermal machines used to transform the energy released in combustion with a hydrocarbon into mechanical power, in order to drive a machine or generate thrust in aircraft. The critical issue in the GT design are the parts exposed to extreme mechanical and thermal conditions, e.g., the first row of turbine blades. The GT thermal efficiency is limited by the maximum temperature the blade materials can withstand without softening or creeping. Currently, the maximum operating temperature is above the softening point of the blade material thanks to techniques of ceramic coatings of low thermal conductivity, called Thermal Barrier Coating (TBC), and techniques of blade cooling. The internal cooling of blades involves conduits inside them for air that comes from a bleed in an intermediate compressor stage. The air bleeding is around 3 to 5% of the main GT flow. This air and the heat flow that it receives are not used to generate power, so it is necessary to optimize the cooling techniques in order to control the temperature using the least amount of air and minimum heat flux evacuated, for holding the GT overall efficiency high. The present work studies the internal cooling of Elemental Gas Turbine Blade (EGTB) with a fixed thickness of the TBC and the optimization of the conduit shape and position over a cross section in 2D. The optimization is carried out by exhaustive searching method based on the Constructal Theory. The optimization of the position, size, and aspect ratio of EGTBs was done for two types of standard elliptical conduits of different geometries, uniformly distributed. Two different objective functions are analyzed: minimum maximum temperature on the metal and maximum heat evacuation efficiency. The outcome of this work establishes that the use of elliptical conduits of aspect ratio 2:5 leads to improvement in the thermal performance of cooled blades. As compared with circular conduits of the same area, elliptical conduits allow transfer of a greater amount of heat; with a correct design, they enable a lower maximum temperature on the metal. Besides, the constructal designs obtained in this study for the minimum maximum relative temperature ˜ T max or maximum heat evacuation efficiency ξ were not identical.Este trabajo tiene una enmienda (ver "Documentos relacionados").Facultad de Ingenierí

Effects Of Length, Complexity, And Grammatical Correctness On Stuttering In Spanish-Speaking Preschool Children

Purpose: To explore the effects of utterance length, syntactic complexity, and grammatical correctness on stuttering in the spontaneous speech of young, monolingual Spanish-speaking children. Method: Spontaneous speech samples of 11 monolingual Spanish-speaking children who stuttered, ages 35 to 70 months, were examined. Mean number of syllables, total number of clauses, utterance complexity (i.e., containing no clauses, simple clauses, or subordinate and/or conjoined clauses), and grammatical correctness (i.e., the presence or absence of morphological and syntactical errors) in stuttered and fluent utterances were compared. Results: Findings revealed that stuttered utterances in Spanish tended to be longer and more often grammatically incorrect, and contain more clauses, including more subordinate and/or conjoined clauses. However, when controlling for the interrelatedness of syllable number and clause number and complexity, only utterance length and grammatical incorrectness were significant predictors of stuttering in the spontaneous speech of these Spanish-speaking children. Use of complex utterances did not appear to contribute to the prediction of stuttering when controlling for utterance length. Conclusions: Results from the present study were consistent with many earlier reports of English-speaking children. Both length and grammatical factors appear to affect stuttering in Spanish-speaking children. Grammatical errors, however, served as the greatest predictor of stuttering.Communication Sciences and Disorder

Warfare, Fiscal Capacity, and Performance

We exploit differences in casualties sustained in pre-modern wars to estimate the impact of fiscal capacity on economic performance. In the past, states fought different amounts of external conflicts, of various lengths and magnitudes. To raise the revenues to wage wars, states made fiscal innovations, which persisted and helped to shape current fiscal institutions. Economic historians claim that greater fiscal capacity was the key long-run institutional change brought about by historical conflicts. Using casualties sustained in pre-modern wars to instrument for current fiscal institutions, we estimate substantial impacts of fiscal capacity on GDP per worker. The results are robust to a broad range of specifications, controls, and sub-samples