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Solid Fraction (solid + fraction)
Selected AbstractsRelationship between thermal conductivity and water content of soils using numerical modellingEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 3 2003P. Cosenza Summary There is no simple and general relationship between the thermal conductivity of a soil, ,, and its volumetric water content, ,, because the porosity, n, and the thermal conductivity of the solid fraction, ,s, play a major part. Experimental data including measurements of all the variables are scarce. Using a numerical modelling approach, we have shown that the microscopic arrangement of water influences the relation between , and ,. Simulated values for n ranging from 0.4 to 0.6, ,s ranging from 2 to 5 W m,1 K,1 and , from 0.1 to 0.4 can be fitted by a simple linear formula that takes into account n, ,s and ,. The results given by this formula and by the quadratic parallel (QP) model widely used in physical property studies are in satisfactory agreement with published data both for saturated rocks and for unsaturated soils. Consequently, the linear formula and the QP model can be used as practical and efficient tools to investigate the effects of water content and porosity on the thermal conductivity of the soil and hence to optimize the design of thermal in situ techniques for monitoring water content. [source] Region-specific assessment of greenhouse gas mitigation with different manure management strategies in four agroecological zonesGLOBAL CHANGE BIOLOGY, Issue 12 2009SVEN G. SOMMER Abstract Livestock farming systems are major sources of trace gases contributing to emissions of the greenhouse gases (GHG) nitrous oxide (N2O) and methane (CH4), i.e. N2O accounts for 10% and CH4 for 30% of the anthropogenic contributions to net global warming. This paper presents scenario assessments of whole-system effects of technologies for reducing GHG emissions from livestock model farms using slurry-based manure management. Changes in housing and storage practice, mechanical separation, and incineration of the solid fraction derived from separation were evaluated in scenarios for Sweden, Denmark, France, and Italy. The results demonstrated that changes in manure management can induce significant changes in CH4 and N2O emissions and carbon sequestration, and that the effect of introducing environmental technologies may vary significantly with livestock farming practice and interact with climatic conditions. Shortening the in-house manure storage time reduced GHG emissions by 0,40%. The largest GHG reductions of 49 to, in one case, 82% were obtained with a combination of slurry separation and incineration, the latter process contributing to a positive GHG balance of the system by substituting fossil fuels. The amount and composition of volatile solids (VS) and nitrogen pools were main drivers in the calculations performed, and requirements to improve the assessment of VS composition and turnover during storage and in the field were identified. Nevertheless, the results clearly showed that GHG emission estimates will be unrealistic, if the assumed manure management or climatic conditions do not properly represent a given country or region. The results also showed that the mitigation potential of specific manure management strategies and technologies varied depending on current management and climatic conditions. [source] Solidification of binary aqueous solution cooled from aboveHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 1 2010Shigeo Kimura Abstract Freezing and melting phenomena are important in many different fields, including crystal growth, casting, metallurgy, geophysics, and oceanography. Solidification of a multi-component solution is the one often observed in nature. In order to investigate basic features of the freezing processes of binary systems, we conducted a series of laboratory experiments in a rectangular box cooled from above using aqueous NaNO3 solution. During the freezing, the solid phase always grows into many needle-like crystals called the mushy layer. We measured the growth of the mushy layer thickness, the solid fraction, the temperature, and the concentration distributions. The average solid fraction is found to increase with time in the mushy layer. This causes a slow descent of the released solute in the mushy layer and its eventual fall into the liquid region below because of gravity. We propose a one-dimensional model to explain the horizontally-averaged mushy layer growth. In the model, the estimate of a heat flux at the mushy-liquid interface due to natural convection is found essential for a correct prediction. The proposed theory predicts well the growth of the mushy-layer and the average solid fraction, once the convective heat flux is properly given. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20278 [source] Robust Airlike Superhydrophobic SurfacesADVANCED MATERIALS, Issue 5 2010Jiann Shieh A two-tier nanostructure comprising a 20-nm-diameter "nanograss" on 100-nm-diameter nanopillars exhibits robust and near-perfect superhydrophobicity, that is, water contact angles close to 180° and sliding angles close to 0°. Although the solid fraction was very low (,0.02%), this surface could support a drop of water under a pressure of 234,Pa. [source] Effect of pressure and temperature on cluster and particle heat transfer in a pressurized circulating fluidized bedINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 14 2001B. V. Reddy Abstract The present work reports the influence of pressure and bed temperature on particle-to-wall heat transfer in a pressurized circulating fluidized bed (PCFB). The particle convection heat transfer plays a dominant role in determining the bed-to-wall heat transfer coefficient. So far, no information is reported on the effect of pressure and bed temperature on particle-to-wall heat transfer in a PCFB in the published literature. The present investigation reports some information in this direction. The effect of system pressure and bed temperature are investigated to study their influence on cluster and particle heat transfer. The particle convection heat transfer coefficient increases with system pressure and bed temperature due to higher cluster thermal conductivity. The increase in particle concentration (suspension density) results in greater cluster solid fraction and also the particle concentration near the wall is enhanced. This results in higher cluster and particle convection heat transfer between the bed and the wall. Higher particle convection heat transfer coefficient results in enhanced heat transfer between the bed and the wall. The results will also help to understand the bed-to-wall heat transfer mechanism in a better way in a PCFB. Copyright © 2001 John Wiley & Sons, Ltd. [source] Polymer flocculation of calcite: Experimental results from turbulent pipe flowAICHE JOURNAL, Issue 4 2006Alex R. Heath Abstract The kinetics of aggregation/breakage of calcite particles flocculated with a high-molecular-weight polymer flocculant has been studied in turbulent pipe flow. The mean flocculation residence time was varied by changing the length of pipe between the flocculant injection point and the in-stream particle-sizing probe (Lasentec FBRM). A variety of pipe sizes and flow rates were used to produce a range of mean fluid shear rates. The mean shear rate was calculated from the pressure drop along the pipe reactor, as measured by manometer, and was found to vary markedly as a function of both the solid fraction and aggregate size. Increased fluid shear increased the initial mixing and aggregation rates, but ultimately lead to a reduced final aggregate size due to increased aggregate breakage. Several other process variables were also studied, with the aggregate size increased with flocculant dosage and primary particle size, but reduced at higher solid fraction. © 2005 American Institute of Chemical Engineers AIChE J, 2006 [source] Modeling of transmitted X-ray intensity variation with sample thickness and solid fraction in glycine compactsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2003Wenjin Cao Abstract The previous paper in this series introduced an X-ray diffraction quantitation method for the polymorphic content in tablets made of pure components. Before the method could be transferred, further studies were required to explain the commonly observed X-ray intensity variation in analyzing compacts. The literature typically attributes the variation to partial amorphization under compression and/or to preferred orientation, without much viable explanation or compelling evidence. In this study, changes in intensity in compacts analyzed in transmission geometry were found to be primarily a function of sample thickness and solid fraction. A theoretical model was developed to describe the X-ray powder diffraction (XRPD) intensity as a function of solid fraction, mass absorption coefficient, and thickness. The model was tested on two sets of glycine compacts: one with varying thickness at constant solid fraction, and the other with various solid fractions at a given thickness. The results show that the model predicts the XRPD intensity at any given sample thickness and solid fraction. With this model, the intensity variation of compacts made under different compression conditions can be normalized, making the method transferable to various tablet geometries and facilitating the analysis over expected ranges of formulation and process variation. © 2003 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 92:2345,2353, 2003 [source] Measurements of local flow structures of conical spouted beds by optical fibre probesTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2009Zhiguo Wang Abstract A new calibration set-up was designed and assembled, and a comprehensive sensitivity analysis was conducted to investigate factors that may affect the calibration of the effective distance of an optical fibre particle velocity probe. It is shown that the glass window has the most significant impact on the calibration result. The optical fibre probe was then applied to measure local particle velocities and solid fractions inside a half and a full circular conical spouted bed. It is found that the overall particle velocity profiles, as well as the shapes of the spout and fountain are quite similar in both columns. Un nouveau réglage d'étalonnage a été conçu et assemblé, et une analyse de sensibilité complète a été effectuée afin d'investiguer les facteurs risquant d'avoir un impact sur l'étalonnage de la distance réelle d'une sonde à fibres optiques de la vitesse des particules. Il a été démontré que la fenêtre de vitre a l'impact le plus important sur les résultats de l'étalonnage. La sonde à fibres optiques a par la suite été utilisée pour mesurer les vitesses locales des particules et des fractions de solide à l'intérieur d'un demi et d'un plein lit jaillissant conique circulaire. Il est démontré que l'ensemble des profils de vitesse des particules, ainsi que la forme du bec et de la fontaine sont très semblables dans les deux colonnes. [source] Particle-scale simulation of the flow and heat transfer behaviors in fluidized bed with immersed tubeAICHE JOURNAL, Issue 12 2009Yongzhi Zhao Abstract A kind of new modified computational fluid dynamics-discrete element method (CFD-DEM) method was founded by combining CFD based on unstructured mesh and DEM. The turbulent dense gas,solid two phase flow and the heat transfer in the equipment with complex geometry can be simulated by the programs based on the new method when the k-, turbulence model and the multiway coupling heat transfer model among particles, walls and gas were employed. The new CFD-DEM coupling method that combining k-, turbulence model and heat transfer model, was employed to simulate the flow and the heat transfer behaviors in the fluidized bed with an immersed tube. The microscale mechanism of heat transfer in the fluidized bed was explored by the simulation results and the critical factors that influence the heat transfer between the tube and the bed were discussed. The profiles of average solids fraction and heat transfer coefficient between gas-tube and particle-tube around the tube were obtained and the influences of fluidization parameters such as gas velocity and particle diameter on the transfer coefficient were explored by simulations. The computational results agree well with the experiment, which shows that the new CFD-DEM method is feasible and accurate for the simulation of complex gas,solid flow with heat transfer. And this will improve the farther simulation study of the gas,solid two phase flow with chemical reactions in the fluidized bed. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Exploiting the intracellular compartmentalization characteristics of the S. cerevisiae host cell for enhancing primary purification of lipid-envelope virus-like particlesBIOTECHNOLOGY PROGRESS, Issue 1 2010Gaik Sui Kee Abstract This article demonstrates how the intracellular compartmentalization of the S. cerevisiae host cell can be exploited to impart selectivity during the primary purification of lipid-envelope virus-like particles (VLPs). The hepatitis B surface antigen (HBsAg) was used as the VLP model in this study. Expressed HBsAg remain localized on the endoplasmic reticulum and the recovery process involves treating cell homogenate with a detergent for HBsAg liberation. In our proposed strategy, a centrifugation step is introduced immediately following cell disruption but prior to the addition of detergent to allow the elimination of bulk cytosolic contaminants in the supernatant, achieving ,70% reduction of contaminating yeast proteins, lipids, and nucleic acids. Recovery and subsequent treatment of the solids fraction with detergent then releases the HBsAg into a significantly enriched product stream with a yield of ,80%. The selectivity of this approach is further enhanced by operating under moderate homogenization pressure conditions (,400 bar). Observed improvements in the recovery of active HBsAg and reduction of contaminating host lipids were attributed to the low-shear conditions experienced by the HBsAg product and reduced cell fragmentation, which led to lower coextraction of lipids during the detergent step. As a result of the cleaner process stream, the level of product capture during the loading stage of a downstream hydrophobic interaction chromatography stage increased by two-fold leading to a concomitant increase in the chromatography step yield. The lower level of exposure to contaminants is also expected to improve column integrity and lifespan. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] | ||||||||||||||||