CAI combustion with methanol and ethanol in an air-assisted direct injection SI engine

Copyright © 2009 SAE International. This paper is posted on this site with permission from SAE International. Further use of this paper is not permitted without permission from SAECAI combustion has the potential to be the most clean combustion technology in internal combustion engines and is being intensively researched. Following the previous research on CAI combustion of gasoline fuel, systematic investigation is being carried out on the application of bio-fuels in CAI combustion. As part of an on-going research project, CAI combustion of methanol and ethanol was studied on a single-cylinder direct gasoline engine with an air-assisted injector. The CAI combustion was achieved by trapping part of burnt gas within the cylinder through using short-duration camshafts and early closure of the exhaust valves. During the experiment the engine speed was varied from 1200rpm to 2100rpm and the air/fuel ratio was altered from the stoichiometry to the misfire limit. Their combustion characteristics were obtained by analysing cylinder pressure trace. The experimental results show that both oxygenate fuels, methanol and ethanol, can lead to CAI combustion as well as gasoline fuel. The load of CAI combustion was increased and emissions were lower with the two oxygenate fuels. Methanol was found to have highest output and lowest energy consumption among the three fuels tested. CAI combustion characteristics of the oxygenate fuels were more affected by the amount of burnt residuals trapped than that of gasoline fuel

Experimental sensitivity analysis and control of thermoacoustic systems

In this paper, we report the results of an experimental sensitivity analysis on a thermoacoustic system – an electrically heated Rijke tube. We measure the change of the linear stability characteristics of the system, quantified as shifts in the growth rate and oscillation frequency, that is caused by the introduction of a passive control device. The control device is a mesh, which causes drag in the system. The rate of growth is slow, so the growth rate and frequency can be measured very accurately over many hundreds of cycles in the linear regime with and without control. These measurements agree qualitatively well with the theoretical predictions from adjoint-based methods of Magri & Juniper (J. Fluid Mech., vol. 719, 2013, pp. 183–202). This agreement supports the use of adjoint methods for the development and implementation of control strategies for more complex thermoacoustic systems.This is the author accepted manuscript. The final version is available from Cambridge University Press via http://dx.doi.org/10.1017/jfm.2015.71

Fat content reduction and lipid profile improvement in Portuguese fermented sausages alheira

Due to the current trend to reduce fat consumption, the meat food industry, has been increasing the strategies to produce and commercialize products where the reduction or even elimination of saturated fat is an important goal. This study aimed to test different formulas to reduce the fat content and improve the lipid profile in the Portuguese fermented sausage alheira. Data indicate that the three composition formulas of alheiras tested are not a hypercaloric product and the fatty acid profile could be improved changing the sources of fat and specie of meat, particularly reducing the palmitic and stearic acids and the myristic acid contents and increasing the oleic, linoleic and palmitoleic acid contents. The industry could diversify its offer with two new composition formulas, a pork-free alheira, and oil-free alheira, reducing the fat content and improving the fatty acid profile.The authors are grateful to Bísaro – Salsicharia Tradicional industry and to Laboratory of Carcass and Meat Quality of Agriculture School of Polytechnic Institute of Bragança ‘Cantinho do Alfredo’. The authors are members of the Healthy Meat network, funded by CYTED (ref. 119RT0568).info:eu-repo/semantics/publishedVersio

G protein-coupled receptor 37-like 1 modulates astrocyte glutamate transporters and neuronal NMDA receptors and is neuroprotective in ischemia

We show that the G protein-coupled receptor GPR37-like 1 (GPR37L1) is expressed in most astrocytes and some oligodendrocyte precursors in the mouse central nervous system. This contrasts with GPR37, which is mainly in mature oligodendrocytes. Comparison of wild type and Gpr37l1(-/-) mice showed that loss of GPR37L1 did not affect the input resistance or resting potential of astrocytes or neurons in the hippocampus. However, GPR37L1-mediated signalling inhibited astrocyte glutamate transporters and - surprisingly, given its lack of expression in neurons - reduced neuronal NMDA receptor (NMDAR) activity during prolonged activation of the receptors as occurs in ischemia. This effect on NMDAR signalling was not mediated by a change in the release of D-serine or TNF-α, two astrocyte-derived agents known to modulate NMDAR function. After middle cerebral artery occlusion, Gpr37l1 expression was increased around the lesion. Neuronal death was increased by ∼40% in Gpr37l1(-/-) brain compared to wild type in an in vitro model of ischemia. Thus, GPR37L1 protects neurons during ischemia, presumably by modulating extracellular glutamate concentration and NMDAR activation

Mean-field model of melting in superheated crystals based on a single experimentally measurable order parameter

Melting is one of the most studied phase transitions important for atomic, molecular, colloidal, and protein systems. However, there is currently no microscopic experimentally accessible criteria that can be used to reliably track a system evolution across the transition, while providing insights into melting nucleation and melting front evolution. To address this, we developed a theoretical mean-field framework with the normalised mean-square displacement between particles in neighbouring Voronoi cells serving as the local order parameter, measurable experimentally. We tested the framework in a number of colloidal and in silico particle-resolved experiments against systems with significantly different (Brownian and Newtonian) dynamic regimes and found that it provides excellent description of system evolution across melting point. This new approach suggests a broad scope for application in diverse areas of science from materials through to biology and beyond. Consequently, the results of this work provide a new guidance for nucleation theory of melting and are of broad interest in condensed matter, chemical physics, physical chemistry, materials science, and soft matter

Production of ethanol from winter barley by the EDGE (enhanced dry grind enzymatic) process

<p>Abstract</p> <p>Background</p> <p>US legislation requires the use of advanced biofuels to be made from non-food feedstocks. However, commercialization of lignocellulosic ethanol technology is more complex than expected and is therefore running behind schedule. This is creating a demand for non-food, but more easily converted, starch-based feedstocks other than corn that can fill the gap until the second generation technologies are commercially viable. Winter barley is such a feedstock but its mash has very high viscosity due to its high content of β-glucans. This fact, along with a lower starch content than corn, makes ethanol production at the commercial scale a real challenge.</p> <p>Results</p> <p>A new fermentation process for ethanol production from Thoroughbred, a winter barley variety with a high starch content, was developed. The new process was designated the EDGE (enhanced dry grind enzymatic) process. In this process, in addition to the normal starch-converting enzymes, two accessory enzymes were used to solve the β-glucan problem. First, β-glucanases were used to hydrolyze the β-glucans to oligomeric fractions, thus significantly reducing the viscosity to allow good mixing for the distribution of the yeast and nutrients. Next, β-glucosidase was used to complete the β-glucan hydrolysis and to generate glucose, which was subsequently fermented in order to produce additional ethanol. While β-glucanases have been previously used to improve barley ethanol production by lowering viscosity, this is the first full report on the benefits of adding β-glucosidases to increase the ethanol yield.</p> <p>Conclusions</p> <p>In the EDGE process, 30% of total dry solids could be used to produce 15% v/v ethanol. Under optimum conditions an ethanol yield of 402 L/MT (dry basis) or 2.17 gallons/53 lb bushel of barley with 15% moisture was achieved. The distillers dried grains with solubles (DDGS) co-product had extremely low β-glucan (below 0.2%) making it suitable for use in both ruminant and mono-gastric animal feeds.</p

Grain-size variability of point-bar deposits from a fine-grained dryland river terminus, Southern Altiplano, Bolivia

Point-bar deposits exhibiting fining-upward grain-size trends are widely documented from both modern rivers and ancient preserved successions. However, in some mud-dominated sedimentary systems this common pattern may not occur; rather, alternative coarsening-upward trends can develop. We investigated point-bar deposits in the mud-dominated river terminus (median value (D50) < 55 μm) of the meandering Río Colorado in Bolivia's southern Altiplano, a semi-arid endorheic basin. Grain-size trends were investigated using double random grain-size distribution (GSD) measurements and end-member modelling analyses (EMMA), as well as detailed mineralogical analyses (XRD and LOI). These methods revealed an upward-coarsening trend of point-bar deposits in terms of D50 of GSD and in proportions of coarse sediment for two (C2 and C0) of three chronologically different meandering channels in the river terminus. Those of another abandoned channel (C1) were, by contrast, dominated by a fining-upward trend. The deposits in channel C2 were characterised by a lower content of organic matter and carbonate compared with those of the other two channels. A novel conceptual model for the formation of coarsening-upward point-bar deposits is proposed. The model implies the action of low-frequency, high-magnitude floods during an overall hyper-arid period when sediment supply to the river terminus is dominated by clay and fine silt. A temporal trend toward higher magnitude and longer duration flood events allows for the transport coarser-grained sediments further down system toward the river terminus where deposition occurs on the inner bend of meandering channels. Successive accretion layers within the point-bar deposits record a coarsening upward trend. Results demonstrate how a coarsening-upward succession of point-bar deposits in the muddy river terminus of a semi-arid endorheic basin can contribute to improved understanding of mechanisms of deposition in fine-grained fluvial systems. Our results contribute to an improved understanding of the varied processes and sedimentology of very fine-grained meandering river terminus systems in semi-arid or arid endorheic basins; the results additionally provide insight to enable improved interpretations of rock record examples of pre-vegetation rivers on Earth and other planetary bodies

Imaging Oxygen Distribution in Marine Sediments. The Importance of Bioturbation and Sediment Heterogeneity

The influence of sediment oxygen heterogeneity, due to bioturbation, on diffusive oxygen flux was investigated. Laboratory experiments were carried out with 3 macrobenthic species presenting different bioturbation behaviour patterns:the polychaetes Nereis diversicolor and Nereis virens, both constructing ventilated galleries in the sediment column, and the gastropod Cyclope neritea, a burrowing species which does not build any structure. Oxygen two-dimensional distribution in sediments was quantified by means of the optical planar optode technique. Diffusive oxygen fluxes (mean and integrated) and a variability index were calculated on the captured oxygen images. All species increased sediment oxygen heterogeneity compared to the controls without animals. This was particularly noticeable with the polychaetes because of the construction of more or less complex burrows. Integrated diffusive oxygen flux increased with oxygen heterogeneity due to the production of interface available for solute exchanges between overlying water and sediments. This work shows that sediment heterogeneity is an important feature of the control of oxygen exchanges at the sediment–water interface

Electron-Spin Excitation Coupling in an Electron Doped Copper Oxide Superconductor

High-temperature (high-Tc) superconductivity in the copper oxides arises from electron or hole doping of their antiferromagnetic (AF) insulating parent compounds. The evolution of the AF phase with doping and its spatial coexistence with superconductivity are governed by the nature of charge and spin correlations and provide clues to the mechanism of high-Tc superconductivity. Here we use a combined neutron scattering and scanning tunneling spectroscopy (STS) to study the Tc evolution of electron-doped superconducting Pr0.88LaCe0.12CuO4-delta obtained through the oxygen annealing process. We find that spin excitations detected by neutron scattering have two distinct modes that evolve with Tc in a remarkably similar fashion to the electron tunneling modes in STS. These results demonstrate that antiferromagnetism and superconductivity compete locally and coexist spatially on nanometer length scales, and the dominant electron-boson coupling at low energies originates from the electron-spin excitations.Comment: 30 pages, 12 figures, supplementary information include