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961.
The aim of this study was to investigate the potential of using the resistivity and deposition rate data from Crossflow Sampler-Modified Fouling Index Ultrafiltration (CFS-MFIUF) measurements to determine the coupled effects of colloidal fouling and cake enhanced osmotic pressure (CEOP) effect. Cake filtration derived from CFS-MFIUF was combined with a CEOP model to predict the crossflow RO fouling profile under constant flux filtration. The prediction based on resistivity, I′ from CFS-MFIUF measurement alone was found to underestimate the RO fouling for high salinity solutions. However, when incorporating the mass information from the CFS-MFIUF test to account for the CEOP effect, the prediction showed good agreement with the TMP profile of the RO system. The results indicated that the CFS-MFIUF test which includes the CEOP effect is a very promising technique to provide an estimation of the RO colloidal fouling profile. When the changes of cake thickness and porosity throughout the filtration were considered, the predicted TMP profile based on the model clearly indicated a two-stage of fouling profile which agreed well with the experimental data. Additional studies on the effects of cake thickness and porosity on CEOP highlighted the important influence of cake structure on CEOP. 相似文献
962.
963.
Anthony G. Dixon M. Ertan Taskin Michiel NijemeislandE. Hugh Stitt 《Computers & Chemical Engineering》2011,35(7):1171-1185
To develop and validate meshes for computational fluid dynamics (CFD) simulations of transport in fixed beds, a single particle is often used as a test case. We present results for drag coefficient (CD) and heat transfer Nusselt number (Nu) for flow past a sphere, focusing on high flow rates typical of industrial steam reformers (400 < Re < 20,000). Over this range, good predictions of CD were obtained using large eddy simulation (LES) to capture vortex shedding and wake dynamics, with a mesh refined downstream from the sphere. The small time-steps and high cell count required make this too expensive for fixed beds. Nu can be accurately calculated using a Reynolds-averaged Navier-Stokes (RANS) method with shear-stress transport (SST) k-ω closure provided the mesh at the particle surface is fine enough and covers most of the boundary layer. Single sphere simulations of heat transfer are more useful for fixed bed mesh development than drag coefficient calculations. 相似文献
964.
The city of Logan, Utah treats wastewater in 460 acres of facultative lagoons. Naturally growing algae in these lagoons uptake nutrients and remediate the wastewater, but require coagulation and flocculation for separation from wastewater. Cationic corn starch and cationic potato starch with a degree of substitution 1.34 and 0.82, respectively, were synthesized using 3‐methacryloyl amino propyl trimethyl ammonium chloride and tested on Scenedesmus obliquus and lagoon wastewater. The zeta potential of the cationic starches tested over a pH range 5.0–10.0 showed an average of +16.0 and +15.1 mV for cationic corn starch and cationic potato starch, respectively. Total suspended solids removals of 90 and 85% were achieved with cationic corn starch and cationic potato starch, respectively, when tested with S. obliquus. Tests with wastewater showed total suspended solids removals of 80 and 60% for cationic corn starch and cationic potato starch, respectively. Total phosphorus removal values from wastewater were approximately 33, 29, and 42% for cationic corn starch, cationic potato starch, and alum, respectively, for a coagulant/algae ratio of 1.4 (wt/wt). These results indicate that cationic starch has the potential to replace alum for algae harvesting and wastewater treatment making it a suitable alternative to inorganic coagulants and flocculants. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2572–2578, 2013 相似文献
965.
Chiara E. Ghezzi Jelena Rnjak-Kovacina Anthony S. Weiss David L. Kaplan 《Israel journal of chemistry》2013,53(9-10):777-786
New multifunctional, degradable, polymeric biomaterial systems would provide versatile platforms to address cell and tissue needs in both in vitro and in vivo environments. While protein-based composites or alloys are the building blocks of biological organisms, similar systems have not been largely exploited, to date, to generate ad hoc biomaterials able to control and direct biological functions by recapitulating their inherent structural and mechanical complexities. Therefore, we have recently proposed silk tropoelastin material platforms that are able to conjugate a mechanically robust and durable protein, silk, to a highly flexible and biologically active protein, tropoelastin. This review focuses on the elucidation of the interactions between silk and tropoelastin to control the structure of the material its properties, and ultimately functions. In addition, an approach is provided for novel material designs to provide tools to control biological outcomes through surface roughness, elasticity, and net charge for neuronal and mesenchymal stem-cell-based tissue engineering. 相似文献
966.
Anthony C. Comer Cláudio P. Ribeiro Benny D. Freeman Sumod Kalakkunnath Douglass S. Kalika 《Polymer》2013,54(2):891-900
The glass–rubber and sub-glass relaxation characteristics of ortho-functionalized aromatic polyimides and thermally rearranged polymers were investigated by dynamic mechanical and dielectric methods. Soluble polyimides (HAB–6FDA; APAF–ODPA) were synthesized by chemical and thermal imidization and subject to thermal rearrangement at elevated temperature. For the thermal exposure histories investigated, mass loss studies indicated partial conversion of the polyimide precursor, suggesting the formation of TR copolymers containing both benzoxazole units and residual imide segments. Measurement of storage modulus and loss tangent was used to follow the thermal rearrangement process in-situ as reflected in the suppression of the polyimide glass transition as a function of precursor structure, the nature of the ortho functional groups and prior thermal exposure. In addition, changes in the position and intensity of local relaxations detected across the sub-glass temperature range were correlated with the degree of thermal rearrangement in these polymers. 相似文献
967.
Muniyandi Jeyaraj Senthilkumar Varadan Kevin John Pulikotil Anthony Muralidharan Murugan Ashok Raja Sangiliyandi Gurunathan 《Journal of Industrial and Engineering Chemistry》2013,19(4):1299-1303
Here, we describe biosynthesis of silver nanoparticles by reduction of aqueous Ag+ ions with the culture supernatant of Pseudomonas aeruginosa. The morphological, physiological, biochemical and molecular level identification of the strain GS1 resembles P. aeruginosa. The nanoparticles synthesized by P. aeruginosa were characterized by UV–vis spectroscopy, dynamic light scattering (DLS) and scanning electron microscopy (SEM). The size-distribution of nanoparticles was determined using a particle-size analyzer and the average particle-size was found to be 80 nm. The biological activities of the synthesized silver nanoparticles like antimicrobial activity were confirmed against Escherichia coli and Staphylococcus aureus and it have stable anti-coagulant effect. 相似文献
968.
Giacomo Piccinelli Anthony Finkelstein Tommaso Costa 《Information and Software Technology》2003,45(15):1061-1063
The time and costs involved in connecting the IT systems of two companies impact the actual formation of business relationships. A flexible infrastructure for process management is instrumental for rapid and cost-effective B2B integration. One dimension of flexibility that system integrators identify as critical is node-level interaction. In this paper, we discuss the findings of the Nile project on B2B process integration. In particular, we present the methodology defined in Nile for the semi-automatic reconciliation of node-level incompatibilities. 相似文献
969.
Vijay Sivan Shi‐Yang Tang Anthony P. O'Mullane Phred Petersen Nicky Eshtiaghi Kourosh Kalantar‐zadeh Arnan Mitchell 《Advanced functional materials》2013,23(2):144-152
Liquid metal marbles that are droplets of liquid metal encapsulated by micro‐ or nanoparticles are introduced. Droplets of galinstan liquid metal are coated with insulators (including Teflon and silica) and semiconductors (including WO3, TiO2, MoO3, In2O3 and carbon nanotubes) by rolling over a powder bed and also by submerging in colloidal suspensions. It is shown that these marbles can be split and merged, can be suspended on water, and are even stable when moving under the force of gravity and impacting a flat solid surface. Furthermore, the marble coating can operate as an active electronic junction and the nanomaterial coated liquid metal marble can act as a highly sensitive electrochemical based heavy metal ion sensor. This new element thus represents a significant platform for the advancement of research into soft electronics. 相似文献
970.
Colin L. Freeman James A. Dawson Hung‐Ru Chen Liubin Ben John H. Harding Finlay D. Morrison Derek C. Sinclair Anthony R. West 《Advanced functional materials》2013,23(31):3925-3928
The energetics of La‐doping in BaTiO3 are reported for both (electronic) donor‐doping with the creation of Ti3+ cations and ionic doping with the creation of Ti vacancies. The experiments (for samples prepared in air) and simulations demonstrate that ionic doping is the preferred mechanism for all concentrations of La‐doping. The apparent disagreement with electrical conduction of these ionic doped samples is explained by subsequent oxygen‐loss, which leads to the creation of Ti3+ cations. Simulations show that oxygen‐loss is much more favorable in the ionic‐doped system than undoped BaTiO3 due to the unique local structure created around the defect site. These findings resolve the so‐called “donor‐doping” anomaly in BaTiO3 and explain the source of semiconductivity in positive temperature coefficient of resistance (PTCR) BaTiO3 thermistors. 相似文献