bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and antimicrobial activity of metronidazole containing polymer and copolymers
Authors: Kenawy El‐Refaie , Al‐Deyab Salem S. , Omar Shaker Nihal , El‐Sadek Baheya Mohamed , Khattab Abeer H. B. 
Published: March 2009

AbstractHomopolymer and copolymers containing metronidazole (MTZ) drug were synthesized. Acryloyl chloride was reacted with MTZ (drug) to produce monomer containing MTZ, and then the monomer was copolymerized with various amounts of methyl methacrylate. The produced monomer, homopolymer, and copolymers were characterized by elemental analysis, IR, and 1H‐NMR. The antimicrobial activities of the synthesized polymers were tested against Kelpsilic as fungal organisms, and Escherichia coli, Bacillus subitilus, and Pesudomonus areuginosa as bacteria organisms. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
UV–VIS absorption and NIR‐stimulated emission of Nd3+: PVA films
Authors: Adiyodi Amrutha K. , Jyothy P. V. , Unnikrishnan N. V. 
Published: March 2009

AbstractNeodymium‐doped polyvinyl alcohol films were prepared and the optical properties of the films were investigated. By applying Judd–Ofelt theory, the Ω parameters were obtained from the absorption spectrum. Various radiative parameters like transition probability for each level (AJ), total transition probability (AT), branching ratio (βR), radiative lifetime (τrad), and absorption cross‐section (σA) were calculated. The theoretically obtained branching ratio and integrated absorption cross‐section are found to be greater for the transition 4F3/2 → 4I11/2. From the emission spectrum peaked at 1064‐nm stimulated emission cross‐section (σE), the line width (Δλeff) is calculated to be 6.21 × 10−21 cm2 and 41 nm, respectively. Further the variation of the optical gain with the length of the film was studied and the slope efficiency (η = 8.5%) was determined from laser measurements. These results clearly support the potentiality of the Nd3+: polyvinyl alcohol films in realizing optical amplification and stimulated emission. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Crystallization behavior of “wet brush” and “dry brush” blends of PS‐b‐PEO‐b‐PS/h‐PEO
Authors: Luo Chunyan , Han Xia , Gao Ying , Liu Honglai , Hu Ying 
Published: March 2009

AbstractThe crystallization behavior of the blending system consists of homopolymer poly(ethylene oxide) (h‐PEO) with different molecular weights, and polystyrene‐block‐poly (ethylene oxide)‐block‐polystyrene (PS‐b‐PEO‐b‐PS) triblock copolymer has been investigated by DSC measurements. The crystallization of PEO block (b‐PEO) in block copolymer occurs under much lower temperature than that of the h‐PEO in the bulk (ΔT > 65 °C), which is attributed to the homogeneous nucleation crystallization behavior of the b‐PEO microdomains. In both the “dry‐brush” and the “wet brush” blending systems, the homogeneous nucleation crystallization temperature of PS‐b‐PEO‐b‐PS/h‐PEO blends increases due to the increase of the domain size. The heterogeneous nucleation crystallization temperatures of h‐PEO in the wet brush blending systems are higher than that of the corresponding h‐PEO in the bulk. At the same time, the heterogeneous nucleation crystallization temperature of b‐PEO10000 decreases from 43°C to 30°C and 40°C in the h‐PEO600 and h‐PEO2000 blending systems, respectively, because of the stretching of the PEO chains in the wet brush. However, this kind of phenomenon does not happen in the dry brush blending systems. The self‐seeding procedure was used to further ascertain the nucleation mechanism in the crystallization process. As a result, the self‐seeding domains have been confirmed, and the difference between the dry brush and wet brush systems has been observed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Influence of EMAA compatibilizer on the structure and properties of HDPE/hydrotalcite nanocomposites prepared by melt mixing
Authors: Ardanuy M. , Velasco J. I. , Maspoch M. L. , Haurie L. , Fernández A. I. 
Published: March 2009

AbstractHigh‐density polyethylene (HDPE)/hydrotalcite nanocomposites were prepared and characterized with a partially neutralized sodium ionomer of poly(ethylene‐co‐methacrylic acid) (EMAA) as a compatibilizer. Moreover, nanocomposites based on this ionomer were characterized as patterns to analyze the interactions between the hydrotalcite sheets and the methacrylic groups on the ionomer. Hydrotalcite particles were organically modified with sodium dodecyl sulfate ions. Their presence in the interlayer space was confirmed by means of Fourier transform infrared spectroscopy (FTIR) and X‐ray diffraction (XRD). Morphological analysis carried out with XRD and transmission electron microscopy (TEM) revealed the partially exfoliated/intercalated structure achieved in the nanocomposites. The mechanical properties of the HDPE nanocomposites mainly depended on the nature of the polymer matrix. Higher values of the tensile strength and Young's modulus were found in the EMAA nanocomposites. Thermogravimetric analysis (TGA) showed that hydrotalcite particles improved the thermal stability and delayed the onset decomposition temperature of both HDPE and EMAA nanocomposites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Magnesium/Copper Nanocomposite through Digestive Ripening
Authors: Kalidindi Suresh Babu , Jagirdar Balaji R. 
Published: March 2009

AbstractComposing nanocomposites: Co‐digestive ripening of as‐prepared Mg and Cu colloids prepared by the solvated metal atom dispersion method results in a highly monodisperse colloid of Mg/Cu nanocomposite with an average particle size of 3.0±0.5 nm. Annealing of these samples at 300 °C gives the Cu/MgO nanocomposite.magnified image
Bioassembly of three‐dimensional embryonic stem cell‐scaffold complexes using compressed gases
Authors: Xie Yubing , Yang Yong , Kang Xihai , Li Ruth , Volakis Leonithas I. , Zhang Xulang , Lee L. James , Kniss Douglas A. 
Published: March 2009

AbstractTissues are composed of multiple cell types in a well‐organized three‐dimensional (3D) microenvironment. To faithfully mimic the tissue in vivo, tissue‐engineered constructs should have well‐defined 3D chemical and spatial control over cell behavior to recapitulate developmental processes in tissue‐ and organ‐specific differentiation and morphogenesis. It is a challenge to build a 3D complex from two‐dimensional (2D) patterned structures with the presence of cells. In this study, embryonic stem (ES) cells grown on polymeric scaffolds with well‐defined microstructure were constructed into a multilayer cell‐scaffold complex using low pressure carbon dioxide (CO2) and nitrogen (N2). The mouse ES cells in the assembled constructs were viable, retained the ES cell‐specific gene expression of Oct‐4, and maintained the formation of embryoid bodies (EBs). In particular, cell viability was increased from 80% to 90% when CO2 was replaced with N2. The compressed gas‐assisted bioassembly of stem cell‐polymer constructs opens up a new avenue for tissue engineering and cell therapy. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Simultaneous extraction and concentration of penicillin G by hollow fiber renewal liquid membrane
Authors: Ren Zhongqi , Zhang Weidong , Lv Yuanyuan , Li Jing 
Published: March 2009

AbstractIn this article, hollow fiber renewal liquid membrane (HFRLM) technique was used for recovery of penicillin G from aqueous solution. The organic solution of 7 vol % di‐n‐octylamine (DOA) + 30 vol % iso‐octanol + kerosene was used as liquid membrane phase, and Na2CO3 aqueous solution was used as stripping phase. Experiments were performed as a function of carrier concentration in the organic phase, organic/aqueous volume ratio, pH, and initial penicillin G concentration in the feed phase, pH in the stripping phase, flow rates, etc. The results showed that the HFRLM process was stable and could carry out simultaneous extraction and concentration of penicillin G from aqueous solutions. As a carrier facilitated transport process, the addition of DOA in organic phase could greatly enhance the mass transfer rate; and there was a favorable organic/aqueous volume ratio of 1:20 to 1:30 for this system. The mass transfer flux and overall mass transfer coefficient increased with decreasing pH in the feed phase and increasing pH in the stripping phase, because of variation of the mass transfer driving force caused by pH gradient and distribution equilibrium. The flow rate of the shell side had significant influence on the mass transfer performance, whereas the effect of flow rate of lumen side on the mass transfer performance was slight because of the mass transfer intensification of renewal effect in the lumen side. The results indicated that the HFRLM process was a promising method for the recovery of penicillin G from aqueous solutions. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Anatomy of the patent foramen ovale for the interventionalist
Authors: McKenzie Jeff A. , Edwards William D. , Hagler Donald J. 
Published: March 2009

AbstractBackground: Patent foramen ovale (PFO) is an interatrial communication whose management is controversial. Several manufacturers have submitted protocols for Food and Drug Administration (FDA) approval of their PFO closure device. The purpose of this study was to define anatomy relevant to percutaneous PFO closure, validate the clinical observation that most PFOs contain little tissue rim at the aorta, comment on proposed closure guidelines, and to discuss approaches to PFO closure. Methods: From the Mayo Clinic Tissue Registry, five normal hearts with PFO were selected from each sex from the first 10 decades of life (n = 100). Measurements (mm) included PFO length, diameter, and distance from FO‐superior vena cava (SVC) and FO‐aortic annulus (AoAn). Patient age, weight, and height were obtained from autopsy reports, and body surface area (BSA) was calculated. Results: PFO length and diameter increased with age (P = 0.029 and 0.001, respectively), and FO‐SVC and FO‐AoAn increased with BSA (P ≤ 0.0001 and 0.006, respectively). PFO diameter was larger in women than men (P = 0.028). Using current sizing guidelines, 66% (CI = 56–75%) of the 100patients would have been excluded from device closure, and only 31% could have received the smallest (18 mm) device. Conclusions: Our results suggest that the proposed device closure guidelines may result in inappropriate device sizing. In addition to excluding suitable candidates, strict application of the guidelines could also result in incomplete closure or device embolization. Suggestions for modification of the guidelines and options for device closure are discussed. © 2009 Wiley‐Liss, Inc.
Reactions between germanium and platinum in sub/supercritical water
Authors: Nishikawa E. , Wakao N. 
Published: March 2009

AbstractReactions between platinum and germanium in sub/supercritical water were carried out by exposing a platinum plate to an aqueous solution at 20‐40 MPa and 553‐713 K. The surface of the platinum plate was found to be covered with a film of fine crystals of platinum‐germanium compounds, Pt3Ge, Pt3Ge2, Pt2Ge and PtGe, depending upon the pressures and temperatures of the environment.
A study of supported molybdenum catalysts for the reduction of SO2 with CH4: Effect of sulphidation method
Authors: Mulligan David J. , Tam Kawai , Berk Dimitrios 
Published: March 2009

AbstractAn experimental investigation of the effect of sulphidation method of supported molybdenum catalysts used in the reduction of SO2 with Ch4 was carried out. Two sulphidation methods, one using H2S and the other using a mixture of SO2/CH4, are compared. The methods are evalauted with respect to molybdenum retention, extent of molybdenum sulphidation, and catalytic activity. Mo/Al2O3 catalysts sulphided with H2S are superior to those sulphided under SO2 and CH4 reaction conditions. Although complete sulphidation is never achieved in either of the two cases, the higher activity found with H2S‐sulphided catalysts is attributed to a higher degree of molybdenum sulphidation resulting in a higher MoS2 content. The 15% Mo/Al2O3 catalyst sulphided with H2S at 600°C showed the highest activity and had the highest MoS2 content.
Time optimal control of high dimensional systems by iterative dynamic programming
Authors: Bojkov Bojan , Luus Rein 
Published: March 2009

AbstractFor time optimal control, the problem is first transformed into a finite dimensional optimization problem by using time stages of varying lengths to enable accurate switching, and then solved by iterative dynamic programming. In high dimensional systems care is necessary to ensure convergence to the global optimum. Incorporating penalty functions into the performance index and using an adequate number of stages can yield the global optimum. The use of a continuation approach, where the number of stages in an intermediate solution is systematically increased, appears to be more effective. Three linear systems are used to develop and to test the approaches.
Factors affecting the optimal performance of a high‐yield pulping operation
Authors: Broderick G. , Paris J. , Valade J. L. 
Published: March 2009

AbstractProcess models based on data from close to one hundred pilot scale pulping runs are used to investigate strategies for operating a chemimechanical pulp mill. Optimal values for a total of 55 process and pulp quality variables have been calculated by applying a genetic algorithm search to a fuzzy model of the overall system. This model consists of over 90 distinct empirical relationships. Results indicate that pulp quality is maintained at minimal fibre and energy costs when the chemical pretreatment is conducted at moderately low temperature using a high SO2 concentration producing both high sulphonation and high yield simultaneously. Subsequent refining should involve applying at least 65% of the total energy in the primary stage. The pulp quality obtained is comparable to that of a CTMP pulp but with the added benefit of higher freeness.
Pyrolysis of kraft lignin in molten ZNCL2‐KCL media with tetralin vapor addition
Authors: Kudsy M. , Kumazawa H. , Sada E. 
Published: March 2009

AbstractKraft lignin was pyrolyzed in molten salt media of ZnCl2‐KCl mixture with tetralin vapor added in 0.4 and 4 mol% diluted with N2 in the temperature range of 400 to 700°C. The gas chromatographic analyses of pyrolysis products revealed that the yield of H2 was not increased by tetralin vapor addition. This fact implies that the hydrogen radical produced from tetralin is consumed in the formation of phenolic compounds and light liquids but not in the formation of H2. p‐Cresol was the most abundant phenolic compound. The yield of total phenolic compounds with 4 mol% tetralin vapor added was increased by ca. 80% as compared to that in neat pyrolysis of Kraft lignin.
Catalytic conversion of canola oil to fuels and chemicals over various cracking catalysts
Authors: Katikaneni Sai P. R. , Adjaye John D. , Bakhshi Narendra N. 
Published: March 2009

AbstractThe catalytic conversion of canola oil to fuels and chemicals was studied over HZSM‐5, H‐mordenite, H‐Y, silicalite, aluminum‐pillared clay (AL‐PILC) and silica‐alumina catalysts in a fixed bed micro‐reactor. The reactor was operated at atmospheric pressure, a temperature range of 375−500°C and weight hourly space velocity (WHSV) of 1.8 and 3.6 h−1. An organic liquid product (OLP), light hydrocarbon gases and water were the major products. The objective was to maximize the amount of OLP and its hydrocarbon content as well as optimize the selectivity for gas phase olefinic hydrocarbons. In addition, the performance of each catalyst in terms of minimizing the coke formation was examined. Among the six catalysts, HZSM‐5 gave the highest amount of OLP of 63 mass% at 1.8 WHSV and 400°C. The hydrocarbon content of this OLP product was 83.8 mass%. With the exception of silica‐alumina and aluminum‐pillared clay catalysts, the other catalysts gave high concentrations of aromatic hydrocarbons which ranged between 23.1–95.6 mass% of OLP. The gas products consisted mostly C3 and C4 hydrocarbons. Ethylene, propylene and butanes were some of the valuable hydrocarbon gases. The olefin/paraffin ratio of the gas products was highest for AL‐PILC catalysts but it never exceeded unity. The results showed that it was possible to significantly alter the yield and selectivity for the different hydrocarbon products by using different catalysts or changing the catalyst functionality such as acidity, pore size and crystallinity. Reaction pathways based on these results are proposed for the conversion of canola oil
A simplified model of nitric oxide emission from a circulating fluidized bed combustor
Authors: Talukdar J. , Basu P. 
Published: March 2009

AbstractA simplified mathematical model leading to a closed form of solution is developed for estimation of nitric oxide emission from a coal fired circulating fluidized bed (CFB) furnace. The furnace is divided into two sections: a lower section below and an upper section above the secondary air injection level. Reactions in the cyclone and the return leg are neglected. Furnace dimensions, coal feed rate, coal composition and furnace temperature are inputs to the model which was validated against several pilot scale and commercial units. Experimental results from two pilot plants and two commercial power plants agree with model predictions. A sensitivity analysis was carried out using the model to examine the effect of different operating parameters and coal properties on the overall NO emission from the furnace. It was found that excess air and furnace temperature are most important factors influencing the NO emission level. The primary to secondary air ratio influences the NO emission level reasonably. Properties of coal are other factors which affect the NO emission to a large extent. The model, though it invovles some simplification, predicts the overall emission of NO with a level of accuracy accepted in commercial operation.
Propagation of a nonionic surfactant in radial sandstone cores
Authors: Kwok W. , Hayes R. E. , Nasr‐El‐Din H. A. 
Published: March 2009

AbstractThe dynamic adsorption of a nonionic surfactant, Triton X‐100®, on Berea sandstone with radial flow under a variety of injection rates, salinities and pH is examined. Mathematical modelling of the experimental data shows that the most consistent results are obtained using a kinetic hemimicelle model. The aggregation number (hemimicelle size) is independent of flow rate and salinity, but increases with increasing pH. In all cases, the aggregation number is lower under dynamic conditions than under static conditions, which is attributed to the shear force at the surface. The rate constants for adsorption increase with increasing flow rate, which is attributed to a decrease in mass transfer resistance.
A model for simultaneous measurement of gas and solid holdups in a bubble column using ultrasonic method
Authors: Warsito  , Uchida S. , Maezawa A. , Okamura S. 
Published: March 2009

AbstractThe ultrasonic method developed to measure the dispersed phase holdups in dispersion systems is based on the fact that the velocity of ultrasound in the dispersion is different from that in the liquid. The relationships between velocity differences in the term of transmission time differences of ultrasound and gas holdup in a gas‐liquid system and solid holdup in a liquid‐solid system were derived. The holdups became linearly dependent on the time differences, which is in agreement with the experimental data. Based on those relations, a model for simultaneous measurement of gas and solid holdups in three‐phase systems is proposed. The model permits measurement of the dispersed phase holdups by measuring the transmission time of ultrasound transmitted through the dispersions in two frequencies. It allows investigation of local holdups distributions in a bubble column and in a suspended bubble column.
A model for two‐phase turbulent mixing in a jet bubble column
Authors: Mitra‐Majumdar D. , Farouk B. , Shah Y. T. , Wisecarver K. 
Published: March 2009

AbstractMixing behavior of the two phase air‐water turbulent flow in a jet bubble column is examined. The time evolution of the mixing behavior of a liquid tracer in a turbulent air‐water flow within a jet bubble column is predicted using a model based on the fundamental governing equations of fluid motion. The predictions of the model are compared with experimental measurements. Measured residence time distributions (RTD) of the liquid tracer within the cone agree well with the predicted values given by the model. For the range of parameters considered in the study, lack of radial mixing and large axial mixing are evident within the cone of the jet bubble column. Use of fundamental mathematical models for the study of hydrodynamics in a two‐phase conventional bubble column has been reported earlier (Torvik, 1990; Jakobsen et al., 1993). The present paper extends the use of such models to predict the mixing characteristics in a jet bubble column.
Salt effect of CACL2, NH4i and NAI on vapor‐liquid equilibrium of ethanol + water system at 298.15 K
Authors: Yamamoto Hideki , Terano Tamotsu , Yanagisawa Masahiko , Tokunaga Junji 
Published: March 2009

AbstractSalt effect on vapor‐liquid equilibrium for the ethanol + waiter system was measured at 298.15 K using an experimental apparatus based on the static method. The salting‐out effect of CaCl2, NH4I and NaI on the ethanol + water system follows the order of CaCl2 > NaI > NH4I. The observed experimental data were correlated by the use of a semi‐empirical model proposed by Hála (1983) with an accuracy of ± 2.13%. The application of Hála's model was confirmed in the ethanol + water system to be added the salts other than CaCl2 at 298.15 K.
Line tension and wettability effects on reduced gravity nucleate boiling heat transfer
Authors: Alexander K. L. , Li Dongqing 
Published: March 2009

AbstractLine tension has a significant influence on contact angle during boiling at normal gravity, but previous studies conducted at reduced gravity levels have not considered this parameter. Models were developed to study the validity of neglecting line tension and to examine the influence of contact angle on heat transfer in reduced gravity. It was shown that, although line tension may have an effect at normal gravity, line tension effects are insignificant in reduced gravity. A more non‐wetting liquid on a solid surface has significantly increased heat transfer from the surface to a bubble due to a larger departure radius.
Observer based nonlinear quadratic dynamic matrix control for state space and input/output models
Authors: Gattu Gangadhar , Zafiriou Evanghelos 
Published: March 2009

AbstractAn observer based nonlinear Quadratic Dynamic Matrix Control (QDMC) algorithm is developed for use with nonlinear input‐output (I/O) and state space models. It generalizes and extends previously published nonlinear QDMC algorithms. The extension to I/O models is particularly important due to the increased use of neural networks and other types of nonlinear black box models in the chemical industry. Disturbance rejection and offset free tracking is addressed in a general setting utilizing concepts from filtering theory. Various kinds of disturbance models can be incorporated in the formulation. Even though nonlinear models are utilized for model prediction, the on‐line optimization is formulated as a single Quadratic Program, thus preserving the computational advantages of nonlinear QDMC as compared to Model Predictive Control algorithms based on nonlinear programming techniques. The examples illustrate parameter tuning for open‐loop unstable and stable processes and point out both benefits and shortcomings of the algorithm.