bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and numerical investigation of the precipitation of barium sulfate in a rotating liquid film reactor
Authors: Guo Shengchang , Evans David G. , Li Dianqing , Duan Xue 
Published: June 2009

AbstractPrecipitation of nanosized barium sulfate in a rotating liquid film reactor (RLFR) has been investigated experimentally and through simulations based on the computational fluid dynamics technique including the population balance equation coupled with the Navier–Stokes equations, renormalization group k–ε model equations, and species transport equations. A comparative experiment was carried out involving conventional precipitation in a flask. The structure of the precipitate was identified by powder X‐ray diffraction (PXRD), which showed that the crystals obtained using the RLFR were smaller in size than those obtained in the flask. Transmission electron microscopy (TEM) images demonstrated that the crystals produced by the two different processes had different morphologies. Further detailed experiments involving varying the operating parameters of the RLFR were performed to investigate the effects on crystal size distribution (CSD). Increasing the speed of the rotor in the RLFR in the range 1000–5000 rpm or increasing the rotor‐stator gap in the range 0.1–0.5 mm resulted in a decrease in particle size and narrower particle size distributions. The simulation results suggested that turbulent effects and reaction processes in the effective reactor space were directly related to rotor speed and rotor‐stator gap. The simulated volume weighted mean diameter and CSD of particles of barium sulfate were almost identical to the corresponding experimental results obtained using TEM and laser particle size analyzer. The effects of other parameters such as the Kolmogorov scale and competition between induction time and mixing time are also discussed. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Modeling and simulation of the sequencing batch reactor at a full‐scale municipal wastewater treatment plant
Authors: Ni Bing‐Jie , Xie Wen‐Ming , Liu Shao‐Gen , Yu Han‐Qing , Wang Ying‐Zhe , Gan‐Wang  , Dai Xian‐Liang 
Published: June 2009

AbstractIn this work, we attempted to modify the Activated Sludge Model No.3 and to simulate the performance of a full‐scale sequencing batch reactor (SBR) plant for municipal wastewater treatment. The long‐term dynamic data from the continuous operation of this SBR plant were simulated. The influent wastewater composition was characterized using batch measurements. After incorporating all the relevant processes, the sensitivity of the stoichiometric and kinetic coefficients for the model was thoroughly analyzed prior to the model calibration. The modified model was calibrated and validated with the data from both batch‐ and full‐scale experiments. Model predictions were compared with routine data in terms of chemical oxygen demand, NH4+‐N and mixed liquid volatile suspended solids in the SBR, combined with batch experimental data under different conditions. The model predictions match the experimental results well, demonstrating that the model is appropriate to simulate the performance of a full‐scale wastewater treatment plant even operated under perturbation conditions. © 2009 American Institute of Chemical Engineers AIChE J, 2009
APOE mRNA and protein expression in postmortem brain are modulated by an extended haplotype structure
Authors: Bekris Lynn M. , Galloway Nichole M. , Montine Thomas J. , Schellenberg Gerard D. , Yu Chang‐En 
Published: June 2009

AbstractCurrently the ε4 allele of the apolipoprotein E gene (APOE) is the strongest genetic risk factor for late onset Alzheimer's disease (AD). However, inheritance of the APOE ε4 allele is not necessary or sufficient for the development of AD. Genetic evidence suggests that multiple loci in a 70 kb region surrounding APOE are associated with AD risk. Even though these loci could represent surrogate markers in linkage disequilibrium with APOE ε4 allele, they could also contribute biological effects independent of the APOE ε4 allele. Our previous study identified multiple SNPs upstream from APOE that are associated with cerebrospinal fluid apoE levels, suggesting that a haplotype structure proximal to APOE can influence apoE expression. In this study, we examined apoE expression in human post‐mortem brain (PMB), and constructed chromosome‐phase‐separated haplotypes of the APOE proximal region to evaluate their effect on PMB apoE expression. ApoE protein expression was found to differ among AD brain regions and to differ between AD and control hippocampus. In addition, an extended APOE proximal haplotype structure, spanning from the TOMM40 gene to the APOE promoter, may modulate apoE expression in a brain region‐specific manner and may influence AD disease status. In conclusion, this haplotype–phenotype analysis of apoE expression in PMB suggests that either; (1) the cis‐regulation of APOE expression levels extends far upstream of the APOE promoter or (2) an APOE ε4 allele independent mechanism involving the TOMM40 gene plays a role in the risk of AD. © 2009 Wiley‐Liss, Inc.
Relationship of cranial robusticity to cranial form, geography and climate in Homo sapiens
Authors: Baab Karen L. , Freidline Sarah E. , Wang Steven L. , Hanson Timothy 
Published: June 2009

AbstractVariation in cranial robusticity among modern human populations is widely acknowledged but not well‐understood. While the use of “robust” cranial traits in hominin systematics and phylogeny suggests that these characters are strongly heritable, this hypothesis has not been tested. Alternatively, cranial robusticity may be a response to differences in diet/mastication or it may be an adaptation to cold, harsh environments. This study quantifies the distribution of cranial robusticity in 14 geographically widespread human populations, and correlates this variation with climatic variables, neutral genetic distances, cranial size, and cranial shape. With the exception of the occipital torus region, all traits were positively correlated with each other, suggesting that they should not be treated as individual characters. While males are more robust than females within each of the populations, among the independent variables (cranial shape, size, climate, and neutral genetic distances), only shape is significantly correlated with inter‐population differences in robusticity. Two‐block partial least‐squares analysis was used to explore the relationship between cranial shape (captured by three‐dimensional landmark data) and robusticity across individuals. Weak support was found for the hypothesis that robusticity was related to mastication as the shape associated with greater robusticity was similar to that described for groups that ate harder‐to‐process diets. Specifically, crania with more prognathic faces, expanded glabellar and occipital regions, and (slightly) longer skulls were more robust than those with rounder vaults and more orthognathic faces. However, groups with more mechanically demanding diets (hunter‐gatherers) were not always more robust than groups practicing some form of agriculture. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.
Effect of polyethyleneoxide and sodium chloride over the micellization behavior of sodium dodecyl sulfate
Authors: Baloch Musa Kaleem , Ahmad Farzana , Rauf Abdur , Durrani Gulrez Fatima 
Published: June 2009

AbstractMicellization behavior of sodium dodecyl sulfate (SDS) and its mixture with polyethylene oxide (PEO) are investigated using surface tension and light scattering techniques. The data are presented and interpreted in a novel way, which provides more and reliable information about the interaction of the components. The concentration of SDS corresponding to the initiation of interaction with PEO (T1) and the saturation point (T3) are well identified in this way. It has been observed that the concentration span between T1 and T3 is not much affected by the amount of PEO added. The detail investigation of data concludes that SDS and PEO interactions are in one to one ratio at molecular level and CMC decreases with the addition of salt to the system and the micelles become more compact. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effect of vinyl acetate on aging mechanism of polyacrylate under UV light
Authors: Zhang Weili , Zheng Jing , Huang Guangsu , Li Guangxian 
Published: June 2009

AbstractDiversity of aging behaviors of polyacrylate and poly(vinyl acetate‐acrylate) with the ultraviolet light radiation was studied. The aging degree was evaluated and the mechanism dominated the behaviors was investigated by color aberration, the degree of cross‐linking, molecular weight and its distribution by gel permeation chromatography (GPC), ultraviolet absorption spectroscopy (UV–vis), and fourier transform infrared spectrometer (FTIR). These studies found that although photodegradation mechanism of poly(vinyl acetate‐acrylate) still preserves three main steps of the scission of main chain, formation of double bond and the generation of cross‐linking reaction, introducing structural units of vinyl acetate to polyacrylate cause the rules various. The structural units can aggravate the aging of polyacrylate, through increasing formation of double bonds and generating cross‐linking reaction. However, what is interesting is that the structural units can strikingly restrain main chain from scission. It is significant for modifying the photodegradation behaviors of polyacrylate coatings. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
End pressure corrections in capillary rheometry of concentrated suspensions
Authors: Wang Z. Y. , Joshi S. C. , Lam Y. C. , Chen X. 
Published: June 2009

AbstractThe end effect of a capillary die was investigated on concentrated suspensions with different particle concentrations, using dies with different diameters and at different temperatures. Nonlinearity in the Bagley plots was observed experimentally, and the nonlinearity increased with increasing particle concentration, decreasing temperature, and smaller capillary dies. Calculated end pressures based on the nonlinear Bagley plots were compared with those measured using an orifice die. As the extruded melts tended to stick on the exit wall of the capillary die, measurements by orifice die registered (40–50%) higher losses than those obtained from Bagley corrections. The key factors, which include particle concentration, contraction ratio, temperature, and flow rate, were discussed for their effects on end pressure. A formula was proposed combining the effects of these factors. Good agreement was obtained between the calculated end pressures with predicted results by the proposed formula. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Characterization of random and multiblock copolymers of highly sulfonated poly(arylene ether sulfone) for a proton‐exchange membrane
Authors: Liang Cui , Maruyama Tatsuo , Ohmukai Yoshikage , Sotani Tomohiro , Matsuyama Hideto 
Published: June 2009

AbstractRandom and multiblock copolymers of sulfonated poly(arylene ether sulfone) (SPAES) were synthesized and characterized to compare the differences in the properties of proton‐exchange membranes made with random and multiblock SPAES copolymers. Atomic force microscopy observations and small‐angle X‐ray scattering measurements suggested the presence of nanoscale, clusterlike structures in the multiblock SPAES copolymers but not in the random SPAES copolymers. Proton‐exchange membranes were prepared from random and multiblock copolymers with various ion‐exchange capacities (IECs). The water uptake, proton conductivity, and methanol permeability of the SPAES membranes depended on the IECs of the random and multiblock SPAES copolymers. At the same IEC, the multiblock SPAES copolymers exhibited higher performances with respect to proton conductivity and proton/methanol permeation selectivity than the random SPAES copolymers. The higher performances of the multiblock SPAES copolymers were thought to be due to their clusterlike structure, which was similar to the ionic cluster of a Nafion membrane. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effects of the polymerization and pervaporation operating conditions on the dehydration performance of interfacially polymerized thin‐film composite membranes
Authors: Huang Shu‐Hsien , Jiang George J. , Liaw Der‐Jang , Li Chi‐Lan , Hu Chien‐Chieh , Lee Kueir‐Rarn , Lai Juin‐Yih 
Published: June 2009

AbstractThe disadvantage of dense polyamide membranes when applied in the pervaporation separation process is their low permeation rates. To improve the pervaporation performance, polyamide thin‐film composite membranes were prepared via the interfacial polymerization reaction between ethylenediamine (EDA) and trimesoyl chloride (TMC) on the surface of modified polyacrylonitrile (mPAN) membranes. These composite membranes were applied in the pervaporation separation of alcohol aqueous solutions. On the basis of the best pervaporation performance, the desired polymerization conditions for preparing the polyamide thin‐film composite membranes (EDA–TMC/mPAN) were as follows: (1) the respective concentration and contact time of the EDA aqueous solution were 5 wt % and 30 min and (2) the respective concentration of and immersion time in the TMC organic solution were 1 wt % and 3 min. The polyamide thin‐film composite membranes (EDA–TMC/mPAN) exhibited membrane durability when applied in the pervaporation separation of a 90 wt % isopropyl alcohol aqueous solution at 70°C, which indicated that the polyamide thin film composite (TFC) membranes were suitable for the pervaporation separation process at a high operating temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Thermal degradation analysis of thermoset resins
Authors: Chatterjee Amit 
Published: June 2009

AbstractDynamic mechanical analysis, thermogravimetric analysis, and dielectric analysis (DEA) were conducted for three thermoset resin systems: bismaleimide, epoxy, and vinyl ester. The resin samples were subjected to various degrees of thermal exposure (400, 270, and 330°C for 5–150 min). Dielectric constants were measured along with the thermomechanical properties. The glass‐transition temperature, modulus, and weight loss were important parameters for correlating the material property changes with the heat exposure. A linear relation was determined between the thermomechanical properties and the dielectric properties of the resins under the selected exposure conditions. Therefore, DEA can be introduced as a significant technique for evaluating thermally exposed polymer materials. Interestingly, it is a nondestructive evaluation process. In the future, it could be used for onsite health monitoring of thermally exposed polymer matrix composite structures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Influence of sulfuric acid bath on morphological structure and mechanical properties of poly(p‐phenylene‐1,3,4‐oxadiazole) fibers
Authors: Zhang Zaixing , Ye Guangdou , Li Wentao , Li Ting , Xu Jianjun 
Published: June 2009

AbstractPoly(p‐phenylene‐1,3,4‐oxadiazoles) (p‐PODs) spinning solution was prepared by one‐step polycondensation, and p‐POD fibers were obtained by wet spinning method using dilute sulfuric acid as coagulation bath. The morphology and mechanical properties of p‐POD fibers under different coagulating conditions, such as bath concentration and temperature, were qualitatively and quantitatively studied by microscopes, ultrasonic orientation measurement, WAXD, and other traditional methods. The microscopic observation indicated that the p‐POD fibers were of three‐layer structure which consisted of outer skin, inner skin, and the core. The skin‐core structure and surface feature of the fibers were greatly affected by the coagulating conditions. At the same time, the results of WAXD and ultrasonic orientation measurement demonstrated that the crystallinity and orientation of the fibers also varied with the change of bath conditions. The tests of mechanical properties showed that the tensile strength, elongation at break, and maximum draw ratio of the p‐POD fibers were determined by their solid‐phase structures, which were largely influenced by coagulation conditions. According to the structure analysis and the mechanical tests, the optimal coagulation parameters were chosen to obtain p‐POD fibers with denser and more regular structure and better mechanical properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Transparency and wettability of PVP/PDMS‐IPN synthesized in different organic solvents
Authors: Hillerström Anna , Andersson Martin , Pedersen Jan Skov , Altskär Annika , Langton Maud , van Stam Jan , Kronberg Bengt 
Published: June 2009

AbstractAn interpenetrating polymer network (IPN) combining a hydrophobic polymer (polydimethylsiloxane, PDMS) and a hydrophilic polymer (polyvinylpyrrolidone, PVP) was synthesized in different solvents via a two‐step preparation method. The solvent used during polymerization of the IPN showed a significant impact on the properties of the PVP/PDMS‐IPN. The choice of solvent was affecting both the wettability and transparency of the PVP/PDMS‐IPN. The PVP/PDMS‐IPNs turned hydrophilic in all the solvents used in this study, but the transition from a hydrophobic to a hydrophilic PVP/PDMS‐IPN occurred at lower PVP concentration if a solvent with similar solubility parameter as PVP was chosen. Also, the PVP/PDMS‐IPNs were transparent when the samples were polymerized in a good solvent for PVP. It was concluded that the properties of the PVP/PDMS‐IPN can be tuned by the selection of the solvent used during polymerization. The size of the PVP phase domains in the PVP/PDMS‐IPNs were analyzed with X‐ray scattering techniques (SAXS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC), and the sizes of the domains were found to be smaller than 350 nm. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Adsorption of polyethylene from solution onto starch film surfaces
Authors: Fanta George F. , Salch John H. , Felker Frederick C. , Shogren Randal L. 
Published: June 2009

AbstractWe prepared starch films by jet‐cooking aqueous dispersions of high‐amylose starch and then allowing the jet‐cooked dispersions to air‐dry on Teflon surfaces. When the starch films were immersed in 1% solutions of polyethylene (PE) in 1‐dodecanol, dodecane, and xylene at 120°C and the solutions were allowed to slowly cool, PE precipitated from the solutions and adsorbed onto the starch film surfaces. Fourier transform infrared spectroscopy was used to estimate the micrograms of PE adsorbed per square centimeter of starch film. PE was preferentially adsorbed onto the film side that was in contact with the Teflon surface during drying. The amount of PE adsorbed ranged from about 8 to 45 μg/cm2 and depended upon the solvent used and the final temperature of the cooled solution. Scanning electron microscopy of the starch film surfaces showed discontinuous networks of adsorbed PE on the Teflon side and widely spaced nodules of adsorbed PE on the air side. NMR analysis showed that the PE adsorbed onto the starch surface was more linear and/or had a higher molecular weight than the starting PE. Possible reasons for the selective adsorption of PE onto the Teflon side of the starch film surface are discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Nylon 6 induced morphological developments and electrical conductivity improvements of polypropylene/carbon black composites
Authors: Chen Guangshun , Yang Bo , Guo Shaoyun 
Published: June 2009

AbstractIn this study, a polar conductive filler [carbon black (CB)], a nonpolar polymer [polypropylene (PP)], and a polar polymer [nylon 6 (PA6)] were chosen to fabricate electrically conductive polymer composites by melt blending and compression molding. The morphological developments of these composites were studied. Scanning electron microscopy results showed that in a CB‐filled PP/PA6 (CPA) composite, CB particles were selectively dispersed in PA6 phases and could make the dispersed particles exist as microfiber particles, which could greatly improve the electrical conductivity. The PA6 and CB contents both could affect the morphologies of these composites. The results of electrical resistivity measurements of these composites proved the formation of conductive networks. The resistivity–temperature behaviors of these composites were also studied. For CB‐filled PP (CP) composites, there were apparent positive temperature coefficient (PTC) and negative temperature coefficient (NTC) effects and an unrepeatable resistivity–temperature characteristic. However, for CPA composites, there were no PTC or NTC effects from room temperature to 180°C, and the resistivity–temperature behavior showed a repeatable characteristic; this proved that CB particles were selectively dispersed in the PA6 phase from another point of view. All experimental results indicated that the addition of PA6 to a CP composite could lead to an expected morphological structure and improve the electrical conductivity of the CP composite. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Controlling the deposition of light‐emitting nanofibers/microfibers by the electrospinning of a poly(p‐phenylene vinylene) polyelectrolyte precursor
Authors: Xin Yi , Huang Zonghao , Yang Peipei , Jiang Zijiang , Wang Cheng , Shao Chen 
Published: June 2009

AbstractPoly(p‐phenylene vinylene) (PPV) nanofibers with disordered, helical, and yarn morphologies were controllably prepared by the electrospinning of a cationic polyelectrolyte precursor in an ethanol solution followed by thermal conversion. Through the tuning of the precursor solution properties and processing variables, the factors affecting the morphology of PPV fibers were studied. The diameter of these PPV nanofibers decreased with a decrease in the precursor concentration, and gradual blueshifts and changes in the relative intensity of the vibronic components in photoluminescence spectra were observed. These nanofibers with excellent fluorescent properties are potentially interesting for many applications such as micro‐ and nano‐optoelectronic devices and systems. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and characterization of poly(dimethylamino ethyl methacrylate)–poly(ethylene oxide)–poly(dimethylamino ethyl methacrylate) triblock copolymers
Authors: Tong Dajun , Yao Jia , Wang Qing , Zhai Tao , Li Haoran , Han Shijun 
Published: June 2009

AbstractNovel, monodispersed, and well‐defined ABA triblock copolymers [poly(dimethylamino ethyl methacrylate)–poly(ethylene oxide)–poly(dimethylamino ethyl methacrylate)] were synthesized by oxyanionic polymerization with potassium tert‐butanoxide as the initiator. Gel permeation chromatography and 1H‐NMR analysis showed that the obtained products were the desired copolymers with molecular weights close to calculated values. Because the poly(dimethylamino ethyl methacrylate) block was pH‐ and temperature‐sensitive, the aqueous solution behavior of the polymers was investigated with 1H‐NMR and dynamic light scattering techniques at different pH values and at different temperatures. The micelle morphology was determined with transmission electron microscopy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009