Hydrogen production by sorption-enhanced steam reforming of glycerol

Catalytic steam reforming of glycerol for H(2) production has been evaluated experimentally in a continuous flow fixed-bed reactor. The experiments were carried out under atmospheric pressure within a temperature range of 400-700 degrees C. A commercial Ni-based catalyst and a dolomite sorbent were used for the steam reforming reactions and in situ CO(2) removal. The product gases were measured by on-line gas analysers. The results show that H(2) productivity is greatly increased with increasing temperature and the formation of methane by-product becomes negligible above 500 degrees C. The results suggest an optimal temperature of approximately 500 degrees C for the glycerol steam reforming with in situ CO(2) removal using calcined dolomite as the sorbent, at which the CO(2) breakthrough time is longest and the H(2) purity is highest. The shrinking core model and the 1D-diffusion model describe well the CO(2) removal under the conditions of this work

Immunomodulatory Effect of Toll-Like Receptor-3 Ligand Poly I:C on Cortical Spreading Depression

The release of inflammatory mediators following cortical spreading depression (CSD) is suggested to play a role in pathophysiology of CSD-related neurological disorders. Toll-like receptors (TLR) are master regulators of innate immune function and involved in the activation of inflammatory responses in the brain. TLR3 agonist poly I:C exerts anti-inflammatory effect and prevents cell injury in the brain. The aim of the present study was to examine the effect of systemic administration of poly I:C on the release of cytokines (TNF-α, IFN-γ, IL-4, TGF-β1, and GM-CSF) in the brain and spleen, splenic lymphocyte proliferation, expression of GAD65, GABAAα, GABAAβ as well as Hsp70, and production of dark neurons after induction of repetitive CSD in juvenile rats. Poly I:C significantly attenuated CSD-induced production of TNF-α and IFN-γ in the brain as well as TNF-α and IL-4 in the spleen. Poly I:C did not affect enhancement of splenic lymphocyte proliferation after CSD. Administration of poly I:C increased expression of GABAAα, GABAAβ as well as Hsp70 and decreased expression of GAD65 in the entorhinal cortex compared to CSD-treated tissues. In addition, poly I:C significantly prevented production of CSD-induced dark neurons. The data indicate neuroprotective and anti-inflammatory effects of TLR3 activation on CSD-induced neuroinflammation. Targeting TLR3 may provide a novel strategy for developing new treatments for CSD-related neurological disorders. © 2014, Springer Science+Business Media New York

Immunomodulatory Effect of Toll-Like Receptor-3 Ligand Poly I:C on Cortical Spreading Depression

The release of inflammatory mediators following cortical spreading depression (CSD) is suggested to play a role in pathophysiology of CSD-related neurological disorders. Toll-like receptors (TLR) are master regulators of innate immune function and involved in the activation of inflammatory responses in the brain. TLR3 agonist poly I:C exerts anti-inflammatory effect and prevents cell injury in the brain. The aim of the present study was to examine the effect of systemic administration of poly I:C on the release of cytokines (TNF-α, IFN-γ, IL-4, TGF-β1, and GM-CSF) in the brain and spleen, splenic lymphocyte proliferation, expression of GAD65, GABAAα, GABAAβ as well as Hsp70, and production of dark neurons after induction of repetitive CSD in juvenile rats. Poly I:C significantly attenuated CSD-induced production of TNF-α and IFN-γ in the brain as well as TNF-α and IL-4 in the spleen. Poly I:C did not affect enhancement of splenic lymphocyte proliferation after CSD. Administration of poly I:C increased expression of GABAAα, GABAAβ as well as Hsp70 and decreased expression of GAD65 in the entorhinal cortex compared to CSD-treated tissues. In addition, poly I:C significantly prevented production of CSD-induced dark neurons. The data indicate neuroprotective and anti-inflammatory effects of TLR3 activation on CSD-induced neuroinflammation. Targeting TLR3 may provide a novel strategy for developing new treatments for CSD-related neurological disorders. © 2014, Springer Science+Business Media New York

CFD-DEM Analysis of Particle Attrition in a Jet in a Fluidised Bed

In fluidised bed processes, the solids are in vigorous motion and thus inevitably subjected to mechanical stresses due to inter-particle and particle-wall impacts. These stresses lead to a gradual degradation of the particles by surface wear, abrasion and body fragmentation commonly termed attrition. One significant contribution of attrition comes from the air jets of the fluidised bed distributor. Particles are entrained into the air jet, where they get accelerated and impacted onto the fluidised bed particles. The jet induced attrition only affects the part of the bed which is limited by the jet length, where the mode of attrition is largely collisional. The overall jet attrition rate is therefore the result of the combination of the single particle damage and the flux of particles entering into that region. The attrition behaviour of particles in the jet region is analysed by evaluating their propensity of breakage experimentally and by simulating an air-jet in a bed of particles by CFD-DEM. The frequency of collisions and impact velocities are estimated from which the attrition due to a single air-jet is predicted

Electrocoalescence of water droplets in sunflower oil using a novel electrode geometry

Electrocoalescence is an energy-efficient and environmentally-friendly process for breaking water-in-oil emulsions. It has been used extensively in the oil and petroleum industries. However, the current technology requires long residence times, giving rise to bulky vessels for industrial scale operations and making it less attractive for offshore application. It is also highly desirable to develop compact devices for down-the-well use. In this study, the performance of a novel electrode geometry, a ladder-shaped set of electrodes through which the emulsion flows, is assessed for enhancing the electrocoalescence, hence providing the potential for a compact design. The electrodes are formed into a V shape, with the apex pointing towards the direction of flow. This configuration enables nesting a series of electrodes in a compact form. Furthermore, the water-in-oil emulsion flows through the electrodes rather than passing by them, thus maximizing the effect of the electric field for coalescence. The system under study uses dispersed water droplets in sunflower oil, flowing in a narrow rectangular duct through the electrodes, providing essentially a two-dimensional flowing stream. The performance of this design is investigated for different electrical parameters (i.e. electric field intensity, frequency and waveform), fluid physical properties (i.e. conductivity and water content) and residence time. Of the three types of electric field waveform (i.e. half-sinusoidal, square and sawtooth), sawtooth performs best at high conductivities. Experiments reveal the existence of optimal values of electric field intensity, electric field frequency, salt concentration and water concentration, where the coalescence efficiency is maximum for the current design. Numerical simulation of the electrocoalescence process is conducted to assess the influence of various geometric and process parameters on the coalescence mechanisms of the V-shape electrodes. The outcome of this work is potentially useful for optimizing the design of compact and efficient oil–water separators

Comparison of cohesive powder flowability measured by Schulze Shear Cell, Raining Bed Method, Sevilla Powder Tester and new Ball Indentation Method

Poor powder flow leads to many problems during manufacturing and can lead to inaccurate dosing and off-specification products. Powder flowability is commonly assessed under relatively high applied loads using shear cells by characterising the unconfined yield strength at a range of applied loads. For applied stresses below 1 kPa, it becomes increasingly difficult to obtain reliable values of the unconfined yield strength. The bulk cohesion and tensile strength of the powder are then obtained by extrapolating the yield locus to zero and negative loads, respectively. However, the reliability of this approximation for a given material is not known. To overcome this limitation, techniques such as the Raining Bed Method, Sevilla Powder Tester and the newly-developed Ball Indentation Method may be used. In this paper, we report our measurement results of the tensile strength of glass beads, α-lactose monohydrate and various sizes of fluid catalytic cracking powders determined by the Sevilla Powder Tester and Raining Bed Method and compare them with those inferred from the Schulze Shear Cell. The results of the latter are also compared with those of the Ball Indentation Method. The outcome suggests that in the case of shear cell tests, the extrapolation of the yield locus to lower or negative loads is unsafe. The ball indentation method enables the characterisation of highly cohesive powders at very low compressive loads; however extrapolation to negative loads is still not reliable. In contrast, the Sevilla Powder Tester and Raining Bed Methods are able to characterise the tensile strength directly, but high bulk cohesion poses difficulties as the internal bed failure needs to be analysed in order to reliably estimate the tensile strength. These methods provide a better understanding of powder flow behaviour at low stresses, thus enabling a greater control of manufacturing processes

Electrostatic phase separation: a review

The current understanding and developments in the electrostatic phase separation are reviewed. The literature covers predominantly two immiscible and inter-dispersed liquids following the last review on the topic some 15 years. Electrocoalescence kinetics and governing parameters, such as the applied field, liquid properties, drop shape and flow, are considered. The unfavorable effects, such as chain formation and partial coalescence, are discussed in detail. Moreover, the prospects of microfluidics platforms, non-uniform fields, coalescence on the dielectric surfaces to enhance the electrocoalescence rate are also considered. In addition to the electrocoalescence in water-in-oil emulsions the research in oil-in-oil coalescence is also discussed. Finally the studies in electrocoalescer development and commercial devices are also surveyed. The analysis of the literature reveals that the use of pulsed DC and AC electric fields is preferred over constant DC fields for efficient coalescence; but the selection of the optimum field frequency a priori is still not possible and requires further research. Some recent studies have helped to clarify important aspects of the process such as partial coalescence and drop–drop non-coalescence. On the other hand, some key phenomena such as thin film breakup and chain formation are still unclear. Some designs of inline electrocoalescers have recently been proposed; however with limited success: the inadequate knowledge of the underlying physics still prevents this technology from leaving the realm of empiricism and fully developing in one based on rigorous scientific methodology

Electrocoalescence of water drop trains in oil under constant and pulsatile electric fields

This study addresses the effectiveness of constant and pulsed DC fields in promoting coalescence of dispersed water drops in an oil-continuous phase. For this purpose, a train of drops of relatively uniform size is injected into a stream of flowing sunflower oil. This stream is then admitted to a coalescing section, where an electric field is applied between a pair of ladder-shape bare electrodes. The capability of this device to enhance coalescence of droplets in a chain is investigated at different field intensities, frequencies and waveforms. The effect of the initial inter-droplet separation distance on the process performance is also addressed under constant DC fields. The dominant coalescence mechanism is found to be due to dipole–dipole interaction at low field strength, whereas electrophoresis becomes predominant at higher field strength. Experiments reveal the existence of an optimal frequency, where the average droplet size enlargement is maximized, especially at low field strengths. The droplet size at the outlet of the coalescer is also found to be dependent on the field waveform

Injectable gellan gum-based nanoparticles-loaded system for the local delivery of vancomycin in osteomyelitis treatment

Infection spreading in the skeletal system leading to osteomyelitis can be prevented by the prolonged administration of antibiotics in high doses. However systemic antibiotherapy, besides its inconvenience and often low efficacy, provokes numerous side effects. Thus, we formulated a new injectable nanoparticle-loaded system for the local delivery of vancomycin (Vanc) applied in a minimally-invasive way. Vanc was encapsulated in poly(Llactide- co-glycolide) nanoparticles (NPs) by double-emulsification. The size (258 ± 11 nm), polydispersity index (0.240 ± 0.003) and surface potential (-25.9 ± 0.2 mV) of NPs were determined by dynamic light scattering and capillary electrophoresis measurements. They have a spherical morphology and a smooth topography as observed using atomic force microscopy. Vanc loading and encapsulation efficiencies were 8.8 ± 0.1 and 55.2 ± 0.5 %, respectively, based on fluorescence spectroscopy assays. In order to ensure injectability, NPs were suspended in gellan gum and cross-linked with $Ca^{2+}$; also a portion of dissolved antibiotic was added to the system. The resulting system was found to be injectable (extrusion force 11.3 ± 1.1 N), reassembled its structure after breaking as shown by rheology tests and ensured required burst release followed by sustained Vanc delivery. The system was cytocompatible with osteoblast-like MG-63 cells (no significant impact on cells’ viability was detected). Growth of Staphylococcus spp. reference strains and also those isolated from osteomyelitic joints was inhibited in contact with the injectable system. As a result we obtained a biocompatible system displaying ease of application (low extrusion force), self-healing ability after disruption, adjustable drug release and antimicrobial properties