687 research outputs found

    Effective intraparticle diffusion coefficients of CoCl2 in mesoporous functionalized silica adsorbents

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    The scope of this work is to determine the effective intraparticle diffusion coefficient of CoCl2 over mesoporous functionalized silica. Silica is selected as a carrier of the functionalized groups for its rigid structure which excludes troublesome swelling, often found in polymeric adsorbents. 2-(2-pyridyl)ethyl-functionalized silica is selected as a promising affinity adsorbent for the reversible adsorption of CoCl2. The adsorption kinetics is investigated with the Zero Length Column (ZLC) method. Initially, experiments were performed at different flow rates to eliminate the effect of external mass transfer. The effect of pore size (60 Å and 90 Å), particle size (40⋅10−6 m–1000⋅10−6 m) and initial CoCl2 concentration (1 mol/m3–2.0 mol/m3) on the mass transfer was investigated. A model was developed to determine the pore diffusion coefficient of CoCl2 by fitting the experimental data to the model. The pore diffusion coefficients determined for two different pore sizes of silica are D p (60 Å) =1.95⋅10−10 [m2/s] and D p (90 Å) =5.8⋅10−10 [m2/s]. The particle size and the initial CoCl2 concentration do not have an influence on the value of diffusion coefficient. However, particle size has an influence on the diffusion time constant. In comparison with polymer adsorbents, silica based adsorbents have higher values of diffusion coefficients, as well as a more uniform and stable pore structure

    Phased-array wavelength demultiplexer with flattened wavelength response

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    A four-channel phased-array wavelength demultiplexer with a flattened wavelength response has been realised for the first time in InP/InGaAsP at 1.54 mu m by employing multimode output waveguides. The device has 2 nm channel spacing and a flat response (within 1 dB) of 17 n

    Neural correlates of egocentric and allocentric frames of reference combined with metric and non-metric spatial relations

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    Spatial relations (SRs: coordinate/metric vs categorical/non metric) and frames of reference (FoRs: egocentric/body vs allocentric/external element) represent the building blocks underlying any spatial representation. In the present 7-T fMRI study we have identified for the first time the neural correlates of the spatial representations emerging from the combination of the two dimensions. The direct comparison between the different spatial representations revealed a bilateral fronto-parietal network, mainly right sided, that was more involved in the egocentric categorical representations. A right fronto-parietal circuitry was specialized for egocentric coordinate representations. A bilateral occipital network was more involved in the allocentric categorical representations. Finally, a smaller part of this bilateral network (i.e. Calcarine Sulcus and Lingual Gyrus), along with the right Supramarginal and Inferior Frontal gyri, supported the allocentric coordinate representations. The fact that some areas were more involved in a spatial representation than in others reveals how our brain builds adaptive spatial representations in order to effectively react to specific environmental needs and task demands

    Industrial Process Design for the Production of Aniline by Direct Amination

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    The objective is to design a plant from raw material to product for the production of aniline by direct amination of benzene. The process design is started on a conceptual level and ended on a basic engineering level as well as a techno-economical evaluation. The amination of benzene by hydroxylamine was used as basis. For the production of hydroxylamine four routes are proposed. The most promising route is the chemical reduction of nitric oxide with hydrogen. The process evaluation shows that 27 % of the atomic nitrogen is lost. The atomic carbon efficiency is close to unity. Furthermore, a significant amount of steam can be produced. From an economical perspective, there is still room for improvement because the return of investment is quite low and the payback period is quite high

    Real-world indoor mobility with simulated prosthetic vision:The benefits and feasibility of contour-based scene simplification at different phosphene resolutions

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    Contains fulltext : 246314.pdf (Publisher’s version ) (Open Access)Neuroprosthetic implants are a promising technology for restoring some form of vision in people with visual impairments via electrical neurostimulation in the visual pathway. Although an artificially generated prosthetic percept is relatively limited compared with normal vision, it may provide some elementary perception of the surroundings, re-enabling daily living functionality. For mobility in particular, various studies have investigated the benefits of visual neuroprosthetics in a simulated prosthetic vision paradigm with varying outcomes. The previous literature suggests that scene simplification via image processing, and particularly contour extraction, may potentially improve the mobility performance in a virtual environment. In the current simulation study with sighted participants, we explore both the theoretically attainable benefits of strict scene simplification in an indoor environment by controlling the environmental complexity, as well as the practically achieved improvement with a deep learning-based surface boundary detection implementation compared with traditional edge detection. A simulated electrode resolution of 26 x 26 was found to provide sufficient information for mobility in a simple environment. Our results suggest that, for a lower number of implanted electrodes, the removal of background textures and within-surface gradients may be beneficial in theory. However, the deep learning-based implementation for surface boundary detection did not improve mobility performance in the current study. Furthermore, our findings indicate that, for a greater number of electrodes, the removal of within-surface gradients and background textures may deteriorate, rather than improve, mobility. Therefore, finding a balanced amount of scene simplification requires a careful tradeoff between informativity and interpretability that may depend on the number of implanted electrodes.14 p

    Plasma Apolipoprotein CI and CIII Levels Are Associated With Increased Plasma Triglyceride Levels and Decreased Fat Mass in Men With the Metabolic Syndrome

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    OBJECTIVE—To determine whether, in accordance with observations in mouse models, high concentrations of the lipoprotein lipase inhibitors apolipoprotein (Apo) CI and ApoCIII are associated with increased triglyceride concentrations and decreased fat mass in men with the metabolic syndrome

    Plasma Apolipoprotein CI and CIII Levels Are Associated With Increased Plasma Triglyceride Levels and Decreased Fat Mass in Men With the Metabolic Syndrome

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    OBJECTIVE—To determine whether, in accordance with observations in mouse models, high concentrations of the lipoprotein lipase inhibitors apolipoprotein (Apo) CI and ApoCIII are associated with increased triglyceride concentrations and decreased fat mass in men with the metabolic syndrome

    Trainability of cold induced vasodilatation in fingers and toes

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    Subjects that repeatedly have to expose the extremities to cold may benefit from a high peripheral temperature to maintain dexterity and tissue integrity. Therefore, we investigated if repeated immersions of a hand and a foot in cold water resulted in increased skin temperatures. Nine male and seven female subjects (mean 20.4; SD 2.2 years) immersed their right (trained) hand and foot simultaneously in 8°C water, 30 min daily for 15 days. During the pre and post-test (days 1 and 15, respectively) the left (untrained) hand and foot were immersed as well. Pain, tactile sensitivity and skin temperatures were measured every day. Mean (SD) toe temperature of the trained foot increased from 9.49°C (0.89) to 10.03°C (1.38) (p < 0.05). The trained hand, however, showed a drop in mean finger temperature from 9.28°C (0.54) to 8.91°C (0.44) (p < 0.001) and the number of cold induced vasodilation (CIVD) reactions decreased from 52% during the first test to 24% during the last test. No significant differences occurred in the untrained extremities. Pain diminished over time and tactile sensitivity decreased with skin temperature. The combination of less CIVD responses in the fingers after training, reduced finger skin temperatures in subjects that did show CIVD and the reduced pain and tactile sensitivity over time may lead to an increased risk for finger cold injuries. It is concluded that repeated cold exposure of the fingers does not lead to favorable adaptations, but may instead increase the injury risk
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