Study for the feasibility of fluidized bed membrane reactors: membrane supports reutilization and hydrodynamics at high temperature

Membrane reactors can bring various potential advantages in terms of efficiency and economics for H2 production compared to the benchmark technology based on the Fired Tubular Reforming plant. However, for further implementation at industrial scale still some different aspects should be studied and investigated more in depth, especially those with an important impact on the economics of the process. Membrane costs are still high and can represent up to 15% of the total capital costs in a large scale production plant. A main responsible of these high costs is the high price of the support material (Hastelloy-X). To enhance the success of membrane reactors for hydrogen production, the present work focuses on the study of the reutilization of metallic supported Pd-Ag membrane for high temperature applications, especially by focusing on the reutilization of the support material. In this work, a metallic supported Pd-Ag membrane has been reutilized and tested after continuous operation under high temperatures for more than 1200 h. According to N2 permeance tests done during the characterization of the support for the original membrane and the repaired one, the metallic support might have suffered some sintering during long-term test. Furthermore, part of the ceramic layer of the fresh support membrane remained after the embrittlement, and thus this layer might have become thicker. The repaired membrane has been tested for more than 700 h and lower hydrogen perm-selectivities than in the original membrane are obtained, as well as an expected decrease in permeance. The membrane has also been tested under the influence of different parameters for water gas shift reaction conditions. It has been demonstrated that there is no interaction of the Pd-Ag layer with the Ni/CaAl2O4, thus resulting in a constant permeance in the fluidized bed membrane reactor. However, a catalytic effect of the support material (Inconel) has been observed due to the high CO conversions, besides the effect of the catalyst used. Furthermore, to better understand the behaviour of membrane reactors, especially the fluidized bed membrane reactor concept, better closure equations are needed to describe the fluid-dynamic behaviour of this concept at reacting conditions. In this work, it is aimed to extend a recently fundamental research carried out by Mustafa Taşdemir [1] for fluidized beds at room temperature, who developed a correlation to predict solids movement inside fluidized beds as function of bubble properties using novel optical LED-PIV/DIA techniques. This implies to apply this findings to the recently developed technique to study the hydrodynamic characteristics of fluidized beds at high temperatures, ePIV/DIA. To do so, LED-PIV/DIA and ePIV/DIA techniques are compared at room temperature, resulting in an overestimation of the bubble diameter and an underestimation of the solids hold-up when using the endoscopic technique. It might be related to the larger interrogation area used to treat ePIV/DIA recordings, besides the fact that the endoscope reduces the intensity of the laser hampering the detection of the smallest bubbles and averaging the larger ones. Furthermore, it is located in a corner resulting in a weak illumination at the top and bottom right corners and thus, an underestimation of the solids hold-up is found. The deviations observed between both techniques result in a difficult fitting of theoretical and experimental results at high temperature, hindering the extension of the novel correlation

Coupling Spatial And Time Scales In The Hydrological Modelling Of Mediterranean Regions: WiMMed

Mediterranean catchments usually exhibit strong gradients of both weather variables at different time scales and soil uses, which add complexity to their hydrological modelling, especially in mountainous areas. WiMMed (Water integrated Management model for Mediterranean regions) model was designed to include such variability of scales in an operational suite capable of connecting GIS-based representations of the catchment (soil characteristics and uses, vegetation cover and snow dynamics) with advanced algorithms for simulating the energy and water balance on a physical basis. Widely used throughout the South of Spain, WiMMed efficiently represents the spatial patterns of precipitation, temperature, solar radiation, and evapotranspiration on an hourly basis, the daily evolution of the vegetation cover fraction, and the observed soil use changes over the study period, by means of specific interpolation algorithms and the inclusion of data derived from remote sensing. These high resolution data input to the physical equations of the energy and water balance performed on three series control volumes: canopy, snowpack, and soil, allow for the distributed characterization of water dynamics. Rainfall excess and infiltration and groundwater fluxes are routed towards selected control points along the fluvial network, where the corresponding baseflow, subsurface flow and direct runoff hydrographs that can be routed downstream by means of hydraulic or hydrological equations. WiMMed’s physical basis together with its high resolution multiscale scheme provides managers with an advanced support tool for flood/drought studies, natural regime restitution, short to long term water resource planning, evaluation of changes of soil use, etcetera. This work shows WiMMed capabilities from its use in selected watersheds throughout Andalusia (Spain) performed on the available free-distributed users’ interface designed for technicians and turnkey applications, some of which have been selected as examples

The growth threshold conjecture: a theoretical framework for understanding T-cell tolerance

Adaptive immune responses depend on the capacity of T cells to target specific antigens. As similar antigens can be expressed by pathogens and host cells, the question naturally arises of how can T cells discriminate friends from foes. In this work, we suggest that T cells tolerate cells whose proliferation rates remain below a permitted threshold. Our proposal relies on well-established facts about T-cell dynamics during acute infections: T-cell populations are elastic (they expand and contract) and they display inertia (contraction is delayed relative to antigen removal). By modelling inertia and elasticity, we show that tolerance to slow-growing populations can emerge as a population-scale feature of T cells. This result suggests a theoretical framework to understand immune tolerance that goes beyond the self versus non-self dichotomy.M.A.H. has been partially supported by MINECO grant no. MTM2014-53156. The rest of the authors have not received any particular financial support for this work

Non-destructive methods to estimate physical aging of plywood

This paper studies the relationship between aging, physical changes and the results of non-destructive testing of plywood. 176 pieces of plywood were tested to analyze their actual and estimated density using non-destructive methods (screw withdrawal force and ultrasound wave velocity) during a laboratory aging test. From the results of statistical analysis it can be concluded that there is a strong relationship between the non-destructive measurements carried out, and the decline in the physical properties of the panels due to aging. The authors propose several models to estimate board density. The best results are obtained with ultrasound. A reliable prediction of the degree of deterioration (aging) of board is presented

Integrating Virtual Reality With Activity Management for the Treatment of Fibromyalgia Acceptability and Preliminary Efficacy

Objectives: Cognitive-behavioral therapies (CBT) for fibromyalgia syndrome (FMS) are important interventions in the management of this condition. Empirical evidence reports that although the results are promising, further research is needed to respond more appropriately to these patients. This study focuses on exploring the use of Virtual Reality (VR) as an adjunct to the activity management component. The aim of this study is to present the results of a small-sized randomized controlled trial to test the preliminary efficacy and acceptability of this component. Materials and Methods: The final sample was composed of 61 women diagnosed with FMS according to the American College of Rheumatology. The sample was randomly allocated to 2 conditions: VR treatment and treatment as usual. Results: Participants in the VR condition achieved significant improvements in the primary outcome: disability measured with the FIQ. The improvement was also significant in secondary outcomes, such as perceived quality of life and some of the coping strategies included in the Chronic Pain Coping Inventory: task persistence and exercise. There were no differences in other secondary outcome measures like pain intensity and interference and depression. Participants reported high satisfaction with the VR component. Discussion: The effects were related to the psychological aspects targeted in the treatment. The component was well accepted by FMS patients referred from a public hospital. These findings show that the VR component could be useful in the CBT treatment of FMS and encourage us to continue exploring the use of integrating VR with CBT interventions for the treatment of FMS.The research presented in this paper was funded in part by Fundació La Marató de TV3 (Ajuts de la Marató de TV3 2006), Ministerio de Educación y Ciencia. Spain. PROYECTOS CONSOLIDER-C (SEJ2006-14301/PSIC), Fundació Caixa Castelló-Bancaixa (P11B2009-30), and by Generalitat Valenciana, Redes de Excelencia ISIC (ISIC/2012/012)

Sub-arcsec mid-IR observations of NGC 1614: Nuclear star formation or an intrinsically X-ray weak AGN?

We present new mid-infrared (mid-IR) N-band spectroscopy and Q-band photometry of the local luminous IR galaxy NGC 1614, one of the most extreme nearby starbursts. We analyse the mid-IR properties of the nucleus (central 150 pc) and four regions of the bright circumnuclear (diameter∼600 pc) star-forming (SF) ring of this object. The nucleus differs from the circumnuclear SF ring by having a strong 8–12 μm continuum (low 11.3 μm PAH equivalent width). These characteristics, together with the nuclear X-ray and sub-mm properties, can be explained by an X-ray weak active galactic nucleus (AGN), or by peculiar SF with a short molecular gas depletion time and producing an enhanced radiation field density. In either case, the nuclear luminosity (LIR < 6 × 1043 erg s−1) is only <5 per cent of the total bolometric luminosity of NGC 1614. So this possible AGN does not dominate the energy output in this object. We also compare three star formation rate (SFR) tracers (Pa α, 11.3 μm PAH, and 24 μm emissions) at 150 pc scales in the circumnuclear ring. In general, we find that the SFR is underestimated (overestimated) by a factor of 2–4 (2–3) using the 11.3 μm PAH (24 μm) emission with respect to the extinction corrected Pa α SFR. The former can be explained because we do not include diffuse polycyclic aromatic hydrocarbon (PAH) emission in our measurements, while the latter might indicate that the dust temperature is particularly warmer in the central regions of NGC 1614.We acknowledge support from the Spanish Plan Nacional de Astronomía y Astrofísica through grants AYA2010-21161-C02-01, and AYA2012-32295. AAH and AA acknowledges funding from the Spanish Ministry of Economy and Competitiveness under grants AYA2012-31447 and AYA2012-38491-CO2-02, which are party funded by the FEDER programme.MAPT acknowledges support from the Spanish MICINN through grant AYA2012-38491-C02-02. CRA acknowledges support from a Marie Curie Intra European Fellowship within the 7th European Community Framework Programme (PIEF-GA-2012-327934).Peer Reviewe

Meteomap: Generation Of Meteorological Variables For Distributed Physically-Based Hydrological Modeling

Distributed energy and water balance models require time-series surfaces of the meteorological variables involved in hydrological processes. Most of the hydrological GIS-based models apply simple interpolation techniques to extrapolate the point scale values registered at weather stations at a watershed scale. In mountainous areas, where the monitoring network ineffectively covers the complex terrain heterogeneity, simple geostatistical methods for spatial interpolation are not always representative enough, and algorithms that explicitly or implicitly account for the features creating strong local gradients in the meteorological variables must be applied. Originally developed as a meteorological pre-processing tool for a complete hydrological model (WiMMed), MeteoMap has become an independent software. The individual interpolation algorithms used to approximate the spatial distribution of each meteorological variable were carefully selected taking into account both, the specific variable being mapped, and the common lack of input data from Mediterranean mountainous areas. They include corrections with height for both rainfall and temperature (Herrero et al., 2007), and topographic corrections for solar radiation (Aguilar et al., 2010). MeteoMap is a GIS-based freeware upon registration. Input data include weather station records and topographic data and the output consists of tables and maps of the meteorological variables at hourly, daily, predefined rainfall event duration or annual scales. It offers its own pre and post-processing tools, including video outlook, map printing and the possibility of exporting the maps to images or ASCII ArcGIS formats. This study presents the friendly user interface of the software and shows some case studies with applications to hydrological modeling

Torus and AGN properties of nearby Seyfert galaxies: Results from fitting IR spectral energy distributions and spectroscopy

We used the CLUMPY torus models and a Bayesian approach to fit the infrared spectral energy distributions (SEDs) and ground-based high-angular resolution mid-infrared spectroscopy of 13 nearby Seyfert galaxies. This allowed us to put tight constraints on torus model parameters such as the viewing angle, the radial thickness of the torus Y, the angular size of the cloud distribution sigma_torus, and the average number of clouds along radial equatorial rays N_0. The viewing angle is not the only parameter controlling the classification of a galaxy into a type 1 or a type 2. In principle type 2s could be viewed at any viewing angle as long as there is one cloud along the line of sight. A more relevant quantity for clumpy media is the probability for an AGN photon to escape unabsorbed. In our sample, type 1s have relatively high escape probabilities, while in type 2s, as expected, tend to be low. Our fits also confirmed that the tori of Seyfert galaxies are compact with torus model radii in the range 1-6pc. The scaling of the models to the data also provided the AGN bolometric luminosities, which were found to be in good agreement with estimates from the literature. When we combined our sample of Seyfert galaxies with a sample of PG quasars from the literature to span a range of L_bol(AGN)~10^{43}-10^{47}erg/s, we found plausible evidence of the receding torus. That is, there is a tendency for the torus geometrical covering factor to be lower at high AGN luminosities than at low AGN luminosities. This is because at low AGN luminosities the tori appear to have wider angular sizes and more clouds along radial equatorial rays. We cannot, however rule out the possibility that this is due to contamination by extended dust structures not associated with the dusty torus at low AGN luminosities, since most of these in our sample are hosted in highly inclined galaxies. (Abridged)Comment: Accepted for publication in Ap

Hypothalamic endocannabinoids inversely correlate with the development of diet-induced obesity in male and female mice

The endocannabinoid (eCB) system regulates energy homeostasis and is linked to obesity development. However, the exact dynamic and regulation of eCBs in the hypothalamus during obesity progression remain incompletely described and understood. Our study examined the time course of responses in two hypothalamic eCBs, 2-arachidonoylglycerol (2-AG) and arachidonoylethanolamine (AEA), in male and female mice during diet-induced obesity and explored the association of eCB levels with changes in brown adipose tissue (BAT) thermogenesis and body weight. We fed mice a high-fat diet (HFD), which induced a transient increase (substantial at 7 days) in hypothalamic eCBs, followed by a progressive decrease to basal levels with a long-term HFD. This transient rise at early stages of obesity is considered a physiologic compensatory response to BAT thermogenesis, which is activated by diet surplus. The eCB dynamic was sexually dimorphic: hypothalamic eCBs levels were higher in female mice, who became obese at later time points than males. The hypothalamic eCBs time course positively correlated with thermogenesis activation, but negatively matched body weight, leptinemia, and circulating eCB levels. Increased expression of eCB-synthetizing enzymes accompanied the transient hypothalamic eCB elevation. Icv injection of eCB did not promote BAT thermogenesis; however, administration of thermogenic molecules, such as central leptin or a peripheral β3-adrenoreceptor agonist, induced a significant increase in hypothalamic eCBs, suggesting a directional link from BAT thermogenesis to hypothalamic eCBs. This study contributes to the understanding of hypothalamic regulation of obesity. Keywords: hypothalamus, sexual dimorphism, brown adipose tissu