bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heavy Oil and Bitumen Dehydration—A Comparison Between Disc-Stack Centrifuges and Conventional Separation Technology
Authors: Agrell J. , Faucher M. 
Published: December 2007

Summary
Recent technological advances are making the exploitation of heavy crude oil reserves increasingly profitable. This paper compares nozzle-type disc-stack centrifuges to conventional separation technology for dehydration of heavy oil and bitumen.
The nature and composition of heavy oil leads to a number of undesirable properties, such as its tendency to form stable emulsions in the presence of asphaltenes, particles, and other emulsifiers occurring naturally in the oil. This, combined with a high viscosity and a relatively high solids content, makes dehydration a challenging task that introduces new concerns when compared to dehydrating light crude oil.
As the density of the heavy oil increases and approaches that of water, conventional static and gravity-based separation systems become unacceptably large and require excessive heating and chemical addition to produce pipeline-specification oil. Hence, the disc-stack centrifuge is proposed as a compact and efficient solution, enabling breakdown of stable emulsions and removal of dispersed water droplets and solid contaminants from heavy and viscous crudes in both onshore and offshore installations.
A Central Role for Neuronal AMP-Activated Protein Kinase (AMPK) and Mammalian Target of Rapamycin (mTOR) in High-Protein Diet–Induced Weight Loss
Authors: Ropelle Eduardo R. , Pauli José R. , Fernandes Maria Fernanda A. , Rocco Silvana A. , Marin Rodrigo M. , Morari Joseane , Souza Kellen K. , Dias Marília M. , Gomes-Marcondes Maria C. , Gontijo José A.R. , Franchini Kleber G. , Velloso Lício A. , Saad Mario J.A. , Carvalheira José B.C. 
Published: December 2007

OBJECTIVE—A high-protein diet (HPD) is known to promote the reduction of body fat, but the mechanisms underlying this change are unclear. AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) function as majors regulators of cellular metabolism that respond to changes in energy status, and recent data demonstrated that they also play a critical role in systemic energy balance. Here, we sought to determine whether the response of the AMPK and mTOR pathways could contribute to the molecular effects of an HPD.
RESEARCH DESIGN AND METHODS—Western blotting, confocal microscopy, chromatography, light microscopy, and RT-PCR assays were combined to explore the anorexigenic effects of an HPD.
RESULTS—An HPD reduced food intake and induced weight loss in both normal rats and ob/ob mice. The intracerebroventricular administration of leucine reduced food intake, and the magnitude of weight loss and reduction of food intake in a leucine-supplemented diet are similar to that achieved by HPD in normal rats and in ob/ob mice, suggesting that leucine is a major component of the effects of an HPD. Leucine and HPD decrease AMPK and increase mTOR activity in the hypothalamus, leading to inhibition of neuropeptide Y and stimulation of pro-opiomelanocortin expression. Consistent with a cross-regulation between AMPK and mTOR to control food intake, our data show that the activation of these enzymes occurs in the same specific neuronal subtypes.
CONCLUSIONS—These findings provide support for the hypothesis that AMPK and mTOR interact in the hypothalamus to regulate feeding during HPD in a leucine-dependent manner.
Insulin Internalizes GLUT2 in the Enterocytes of Healthy but Not Insulin-Resistant Mice
Authors: Tobin Vanessa , Le Gall Maude , Fioramonti Xavier , Stolarczyk Emilie , Blazquez Alba G. , Klein Christophe , Prigent Magali , Serradas Patricia , Cuif Marie-Hélène , Magnan Christophe , Leturque Armelle , Brot-Laroche Edith 
Published: December 2007

OBJECTIVES—A physiological adaptation to a sugar-rich meal is achieved by increased sugar uptake to match dietary load, resulting from a rapid transient translocation of the fructose/glucose GLUT2 transporter to the brush border membrane (BBM) of enterocytes. The aim of this study was to define the contributors and physiological mechanisms controlling intestinal sugar absorption, focusing on the action of insulin and the contribution of GLUT2-mediated transport.
RESEARCH DESIGN AND METHODS—The studies were performed in the human enterocytic colon carcinoma TC7 subclone (Caco-2/TC7) cells and in vivo during hyperinsulinemic-euglycemic clamp experiments in conscious mice. Chronic high-fructose or high-fat diets were used to induce glucose intolerance and insulin resistance in mice.
RESULTS AND CONCLUSIONS—In Caco-2/TC7 cells, insulin action diminished the transepithelial transfer of sugar and reduced BBM and basolateral membrane (BLM) GLUT2 levels, demonstrating that insulin can target sugar absorption by controlling the membrane localization of GLUT2 in enterocytes. Similarly, in hyperinsulinemic-euglycemic clamp experiments in sensitive mice, insulin abolished GLUT2 (i.e., the cytochalasin B-sensitive component of fructose absorption), decreased BBM GLUT2, and concomitantly increased intracellular GLUT2. Acute insulin treatment before sugar intake prevented the insertion of GLUT2 into the BBM. Insulin resistance in mice provoked a loss of GLUT2 trafficking, and GLUT2 levels remained permanently high in the BBM and low in the BLM. We propose that, in addition to its peripheral effects, insulin inhibits intestinal sugar absorption to prevent excessive blood glucose excursion after a sugar meal. This protective mechanism is lost in the insulin-resistant state induced by high-fat or high-fructose feeding.
Extended Cartographic Interfaces for Open Distributed Processing
Authors: Sykora Peter , Schnabel Olaf , Enescu Ionut Iosifescu , Hurni Lorenz 
Published: December 2007

In recent years, cartographic Web applications have evolved from closed monolithic applications to open distributed systems in which real-time map rendering components and services play an important role. This progress has required new and flexible ways of defining map symbolization. The development of cartographic interfaces needed to describe the desired map output offers the means to extend current symbolization approaches and adapt the portrayal of data to the most demanding requirements in the area of distributed thematic mapping. This article analyses, in the context of open distributed processing, some of the existing cartographic interfaces that can be used for various cartographic applications and services. At the same time, the article offers a look at the most recent research efforts in this area.
‘Cycle to cycle’ optimizing control of simulated moving beds
Authors: Grossmann Cristian , Amanullah Mohammad , Erdem Gültekin , Mazzotti Marco , Morbidelli Massimo , Morari Manfred 
Published: December 2007

AbstractThe novel feature of the presented simulated moving bed (SMB) controller is its capability to make use of the average outlet concentration of the product streams over a cycle as feedback information, i.e., ‘cycle to cycle’ control. Its effectiveness is confirmed experimentally on an eight‐column four‐section laboratory SMB unit, which is used to separate a binary mixture of the nucleosides, uridine and guanosine. The performance of the ‘cycle to cycle’ SMB control scheme is also demonstrated by several SMB simulation runs that are chosen to test the robustness of the controller. Furthermore, the case where measurements have a time delay is presented. The results illustrate that the ‘cycle to cycle’ controller is able to meet the products' purity specifications and operate the process optimally with minimal information about the system regardless of the disturbances that might take place during the operation. © 2007 American Institute of Chemical Engineers AIChE J, 2008
Micrometer‐sized monodispersed silica spheres with advanced adsorption properties
Authors: Chen Y. , Wang Y. J. , Yang L. M. , Luo G. S. 
Published: December 2007

AbstractMicrometer‐sized monodispersed mesoporous silica spheres with adjustable particle diameter and adjustable pore structure were successfully prepared. Drops of a silica sol were injected by a microfluidic device into a heated oil bath where the droplets solidified during sedimentation. Drop size was varied by control of the rates of the oil flow past the silica sol injector. The silica sol was made by prehydrolysis of tetraethyl orthosilicate (TEOS) in an aqueous acidic solution using a triblock copolymer as the template. Acrylamide monomer was added in the sol after prehydrolysis to accelerate the solidification rate of drops in the oil bath. The amount of monomer was used to control the pore sizes in the silica particles. The effect of synthesis conditions on the morphology and pore structure of spheres was investigated. Silica spheres with different surface morphology and internal structure were obtained by changing the composition of sedimentation medium. Pore diameter and pore‐size distribution can be adjusted effectively by controlling the concentration of silica source, acid or polymeric monomer in the aqueous phase. The prepared silica spheres have high‐surface area (>550 m2/g), large pore volume (>1.1 cm3/g) and large amount of macropores. High‐protein adsorption capacity (520mg/g) was achieved in the adsorption experiments of bovine serum albumin (BSA). Pore structure of silica spheres was demonstrated to be a crucial factor to determine the protein adsorption capacity. © 2007 American Institute of Chemical Engineers AIChE J, 2008
Free surface flow in the mixing zone of an annular centrifugal contactor
Authors: Wardle Kent E. , Allen Todd R. , Anderson Mark H. , Swaney Ross E. 
Published: December 2007

AbstractThe annular centrifugal contactor has been developed as the central piece of equipment for advanced liquid–liquid extraction processes for use in recycling spent nuclear fuel. While a sufficient base of experience exists to support successful operation of current contactor technology, a more complete understanding of the fluid flow within the contactor would enable further advancements in design and operation of future units. In particular, an important characteristic of the flow that is not well understood and which significantly complicates computational modeling of the contactor is the complex free surface flow in the annular mixing zone. This study presents the results of time‐dependent, multiphase computational fluid dynamics (CFD) modeling using the volume‐of‐fluid (VOF) interface tracking method to characterize the mixing zone in a model centrifugal contactor. Laser doppler velocimetry (LDV) measurements of the actual flow velocities within the contactor were also performed. The experimental results were compared with simulations using various turbulence modeling schemes. The CFD model predictions using a coarse grid large eddy simulation (LES) method are in good agreement with the experimental measurements and observations. © 2007 American Institute of Chemical Engineers AIChE J, 2008
Structure and electrochemical properties of polyamide and polyaniline
Authors: Ding Shihai , Chao Danming , Zhang Min , Zhang Wanjin 
Published: December 2007

AbstractElectrochemical properties of well‐defined molecular structured polyamide with amine‐capped aniline pentamer in the main chain and conventional polyaniline were investigated and discussed. CV results suggest that the synthesized polyamide shows a relatively complicated redox process than conventional polyaniline during potential cycling. Differences in ESI characterization revealed that the synthesized polyamide exhibits higher electronic conductivity and lower resistance than the conventional polyaniline. The analysis of molecular configuration based upon the quantum chemistry calculation reveal that the difference in electrochemical activity and conductivity should be ascribed to the influence of system energy, skeleton conjugation, and the Fermi energy of the bipolaron model in the polymer molecules. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of interfacially compatibilized PP‐EPDM thermoplastic vulcanizate/graphite nanocomposites: Effects of graphite microstructure upon morphology, electrical conductivity, and melt rheology
Authors: Katbab A. A. , Hrymak A. N. , Kasmadjian K. 
Published: December 2007

AbstractElectrically conductive PP/EPDM dynamically crosslinked thermoplastic vulcanizate (TPV)/expanded graphite (EG) has been successfully prepared via melt compounding of maleic anhydride grafted polypropylene (PP‐g‐MA)/EG masterbatch and a commercially available TPV material. Correlation between graphite microstructure, and electrical conductivity as well as melt rheological behavior has been studied. Natural graphite flake (NGF), graphite intercalated compound (GIC), and exfoliated graphite (EG) have been employed and compared. Scanning electron microscopy (SEM) showed the presence of 100–200 nm nanolayers in the structure of PP‐g/EG masterbatches, whereas thinner platelets (1.5–2.5 nm) were revealed by transmission electron microscopy (TEM). Better dispersion of the graphite nanolayers in the microstructure of TPV/PP‐g‐MA/EG composite was verified, as the 7.3 Å spacing between the aggregated graphite nanolayers could not be observed in the XRD pattern of this material. TPV/PP‐g/EG nanocomposites exhibited much lower conductivity percolation threshold (φc) with increased conductivity to 10−5 S/cm at EG wt % of 10. Higher nonlinear and nonterminal melt rheological characteristics of dynamic elastic modulus (G′) at low frequency region was presented by the TPV/PP‐g/EG nanocomposites, indicating the formation of nanoscopic conducting multiple networks throughout the continuous TPV matrix. Maleated PP was found to be much more effective in separating EG nanolayers which is attributed to the higher interfacial interaction between PP‐g‐MAH and EG, synergized with its multiporous structure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effects of epoxidized sunflower oil on the mechanical and dynamical analysis of the plasticized poly(vinyl chloride)
Authors: Bouchareb Badra , Benaniba Mohamed Tahar 
Published: December 2007

AbstractEpoxidized soybean oil (ESBO), is one of the most commonly used epoxides because of its typical combined roles as a plasticizer and heat stabilizer. In this study, a novel plasticizer of poly(vinyl chloride) (PVC) resins, epoxidized sunflower oil (ESO), was synthesized, and its performance was evaluated. ESO was designed to act as a coplasticizer and a heat stabilizer like ESBO. ESO is used as organic coplasticizer for plasticized PVC containing Ca and Zn stearates as primary stabilizers and stearic acid as lubricant. Di‐(2‐ethylhexyl) phthalate (DEHP), a conventional plasticizer for PVC, was partially replaced by ESO. Mechanical properties (tensile and shore D hardness) were investigated. The performance of ESO to ESB0 (20 g) for comparison, indicated that ESO could be used as secondary plasticizer for PVC in combination with DEHP. All mechanical and dynamical properties of plasticized PVC sheets varied with the oxirane oxygen of the ESO. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of wood fiber size on extrusion foaming of wood fiber/HDPE composites
Authors: Guo G. , Lee Y. H. , Rizvi G. M. , Park C. B. 
Published: December 2007

AbstractFoaming of wood fiber/plastic composites (WPC) with a fine‐celled structure can offer benefits such as improved ductility and impact strength, lowered material cost, and lowered weight, which can enhance their utility in many applications. Although a great deal of attention is now being focused on these composites in the scientific literature, there are still numerous aspects of WPC processing that need elucidation. In this context, this article investigates the effects of wood fiber (WF) size on fine‐celled extrusion foaming of WPC in terms of cell size, cell size distribution, and foam density. The effects of WF size and coupling agent content on the viscosity of WPC are also investigated. The experimental results revealed that the small‐sized WF provides a better cell morphology, a smaller cell size, and a better cell uniformity in WPC foams. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Organomodified kaolin as a reinforcing filler for natural rubber
Authors: Sukumar Rugmini , Menon A. R. R. 
Published: December 2007

AbstractChina clay (kaolin) has been modified with sodium salt of rubber seed oil (SRSO). SRSO was characterized using X‐ray diffraction (XRD), infrared spectroscopy (FTIR), and differential thermal analysis (DTA). XRD of the unmodified and SRSO‐modified kaolins showed an increase in the d‐(001) spacing of kaolin platelets from 7.15 to 14 Å. FTIR spectroscopy indicated possible grafting of the organic moiety of rubber seed oil (RSO) onto the clay surface. DTA of the SRSO‐modified kaolin indicated that the SRSO is more strongly bound in a constraint environment within the lamellae of kaolin. Natural rubber (NR) mix containing 10 phr of SRSO‐modified kaolin was found to cure faster than that of a similar mix containing unmodified kaolin. NR vulcanizates containing SRSO‐modified kaolin showed considerable increase in tensile modulus, tensile strength, and elongation at break indicating its potential as an organomodified nanofiller. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Kenaf fiber/poly(ε‐caprolactone) biocomposite with enhanced crystallization rate and mechanical properties
Authors: Pan Pengju , Zhu Bo , Dong Tungalag , Serizawa Shin , Iji Masatoshi , Inoue Yoshio 
Published: December 2007

AbstractPlant‐derived kenaf fiber (KF)‐reinforced poly(ε‐caprolactone) (PCL) biocomposites were successfully fabricated by the melt mixing technique. The crystallization behavior, morphology, and mechanical and dynamic mechanical properties of PCL/KF composites with various KF weight contents were investigated. The crystallization rate, tensile and storage moduli significantly improved as compared to the virgin polymer. The half times of PCL/KF composite (20 wt % fiber content) in isothermal crystallization at 40°C and 45°C reduced to 31.6% and 42.0% of the neat PCL, respectively. Moreover, the tensile and storage modulus of the composite are improved by 146% and 223%, respectively, by the reinforcement with 30% KF. The morphology evaluated by SEM indicates good dispersion and adhesion between KF and PCL. Overall, these findings reveal that KF can be a potential reinforcement for the biodegradable polymer composites owing to its good ability to improve the mechanical properties as well as crystallization rate. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Ground particle size influence on the swelling of a copolymer of AA/AMPS in water
Authors: Rosa Fátima , Bordado João , Casquilho Miguel 
Published: December 2007

AbstractThe influence of the ground particle size on the swelling behavior of a copolymer of AA/AMPS in water was observed to determine the best size considering water absorbency in view of fastest and highest equilibrium swelling. The copolymer gel, from acrylamide and 2‐acrylamido‐2‐methyl‐propanosulfonic acid and synthesized in the presence of N,N‐methylene‐bis‐acrylamide, was obtained by a radical solution technique, and identified by FTIR spectroscopy. By grinding, various particle diameters were obtained, and then separated by sieves. Studies of dynamic and equilibrium swelling in deionized water at 20°C showed the influence of the particle size on the kinetics of swelling and its equilibrium swelling capacity. A mathematical model for the absorption, including diffusion and relaxation modes, permitted to assess the absorption mechanism, and offered quantitative information about water diffusivity in the copolymer. The fastest swelling was obtained with diameters of 22.5–215 μm. Particle sizes ranging from 67.5 to 355 μm yielded the greatest equilibrium swelling, with mass ratios of about 1100. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Tensile behavior of polypropylene blended with bimodal distribution of styrene‐ethylene‐butadiene‐styrene particle size
Authors: Mae Hiroyuki , Omiya Masaki , Kishimoto Kikuo 
Published: December 2007

AbstractThe objective is to characterize the effects of the bimodal distribution of rubber particles and its blend ratio on the mechanical properties of the thermoplastic polypropylene blended with two different styrene‐ethylene‐butadiene‐styrene triblock copolymer at the intermediate and high strain rates. Tensile tests are conducted at the nominal strain rates from 3 × 10−1 to 102 (1/s). Phase morphology is investigated to estimate the bimodal rubber particle size distribution. In addition, the in situ observation is conducted during uniaxially stretching within transmission electron microscopy step by step to investigate the deformation events depending on the elongation of samples. The elastic modulus increased gradually as the blend ratio of large rubber particle increased. An increase in the rupture strain and the strain energy up to failure was found for the bimodal rubber particle distributed blend system where the blend ratios of small rubber particle and large rubber particle were same. This is because the smaller particles dominant blend systems show the bandlike craze deformation while the localized plastic deformation is taken place in the larger particles dominated blend systems. The synergistic effect of these rubber particles gives rise to a strong increase in the ductility of these bimodal rubber particle distributed polypropylene systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Structure and property characterization of nanograde core‐shell polyurethane/polyacrylate composite emulsion
Authors: Chai Shu Ling , Tan Hui Min 
Published: December 2007

AbstractAnionic aqueous polyurethane dispersion was synthesized through self‐emulsifing method from cycloaliphatic isophorone diisocyanate (IPDI) and dimethylolpropionic acid (DMPA). The carboxyl acid group in DMPA was used to make the polyurethane dispersible. The polyurethane/polyacrylate (PU/PA) composite particles were also prepared by seeded surfactant‐free emulsion polymerization; the cycloaliphatic polyurethane aqueous dispersion was used as seed particles. The structures and properties of the composite emulsion as well as the physical mixture of polyurethane dispersion and polyacrylate emulsion were characterized by FTIR, DSC, dynamic light scattering, TEM, X‐ray photoelectron spectroscopy (ESCA), and electronic tensile machine. The results showed that the synthesized PU/PA composite emulsion was found to form inverted core‐shell structure with polyacrylate as the core and with polyurethane as the shell, and its diameter of particles is in the range of nanograde, the crosslinking reaction was existed in composite emulsion. The intimate molecular mixing of crosslinking polymers are also claims to result in a superior balance of properties compared to physical blends of polyurethane dispersion and acrylate emulsion. The crosslinking mechanism of PU/PA composite emulsion was also discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and physical properties of photopolymer/SiO2 nanocomposite for rapid prototyping system
Authors: Chiu Shih‐Hsuan , Wu Dien‐Chi 
Published: December 2007

AbstractA photopolymer material was applied in liquid rapid prototyping (RP) machine. The prototype fabricated from photopolymer was difficult for storage due to volumetric shrinkage and deformation during curing. The prototype fabricated from photopolymer suffers from the volumetric shrinkage during curing and the continuing deformation for a creeping period after curing. Therefore, we used nano‐SiO2 as a major additive to modify the physical properties of photopolymer. We also added appropriate dispersant to make nanoparticles distribute uniformly in order to reduce the phase separation in composite material. The experimental results showed that photopolymer/SiO2 nanocomposite can improve tensile strength and hardness by about 50% and offers better dimensional stability. Photopolymer/SiO2 nanocomposite can also increase the degradation temperature and shorten manufacturing time for RP processing. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008