bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blocked polyisocyanates containing fluorine atoms as crosslinking agents for polyurethane powder coatings
Authors: Pilch‐Pitera Barbara 
Published: November 2011

AbstractUsing alicyclic diisocyanates (HDI, TMDI, IPDI, H12MDI), aliphatic unfluorinated and fluorinated alcohols, dibutyltin dilaurate as well as triethylamine as catalysts, blocked polyisocyanate crosslinkers for powder lacquers were synthesized. The chemical structure of these compounds was characterized by means of IR, 1H‐NMR, 13C‐NMR, and 19F‐NMR spectroscopy. Their molecular weight distribution parameters were determined by gel permeation chromatography. These blocked polyisocyanates were used for the production of powder lacquer compositions and coatings. The three‐dimensional surface topography and surface chemical structure of the resulting powder lacquers were investigated by means of confocal microscope and ATR FT‐IR. The values of surface roughness parameters were calculated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of annealing temperature on phase composition and tensile properties in isotactic poly(1‐butene)
Authors: Chvátalová Lenka , Beníček Lubomír , Berková Kristýna , Čermák Roman , Obadal Martin , Verney Vincent , Commereuc Sophie 
Published: November 2011

AbstractThe influence of annealing temperature on the kinetics of polymorphic changes and mechanical properties within the time in isotactic poly(1‐butene) (PB‐1) has been investigated by wide‐angle X‐ray scattering and tensile testing. Extruded tapes of PB‐1 have been exposed to several annealing temperatures: −22, +5, +22, +40 and +60°C. The evolution of content of Phase I for various annealing temperatures upon time shows predominantly S‐shaped trend. Annealing temperature considerably affects the overall rate of transformation in PB‐1. On the other hand, the resulting mechanical properties are solely controlled by the polymorphic composition. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Microwave dielectric properties of flexible butyl rubber–strontium cerium titanate composites
Authors: Janardhanan Chameswary , Thomas Dhanesh , Subodh Ganesanpotti , Harshan Soumya , Philip Jacob , Sebastian Mailadil T. 
Published: November 2011

AbstractButyl rubber–strontium cerium titanate (BS) composites have been prepared by hot pressing. The tensile tests show that the BS composites are flexible. The dielectric properties of the composites have been investigated at 1 MHz and 5 GHz as a function of ceramic contents. The composite with volume fraction 0.43 of ceramic filler has a dielectric constant (εr) of 11.9 and dielectric loss (tan δ) 1.8 × 10−3 at 5 GHz. The measured values of εr are compared with the effective values calculated using different theoretical models. The thermal conductivity of the composites is found to increase with ceramic contents and reaches a value of 4.5 Wm−1 K−1 for maximum filler loading 0.43 volume fraction. The coefficient of thermal expansion of the composites decreases gradually with filler loading and reaches a minimum value of 30.2 ppm °C−1 at a volume fraction 0.43. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of acrylic copolymer dispersants bearing epoxy groups on rheological and dielectric properties of carbon black‐filled epoxy system
Authors: Son Bui Thanh , Kook Yoonbong , Lee Eun Sung , Bae Jin‐Young 
Published: November 2011

AbstractIn this article, the use of copolymeric dispersants with an acrylic backbone and epoxy side groups for formulating carbon black (CB)‐epoxy composites are described. Six epoxy‐containing acrylic copolymer dispersants were prepared from hexyl methacrylate (HMA), poly(ethylene glycol) ethyl ether methacrylate (PEGMA), and glycidyl methacrylate via a group transfer polymerization technique. The epoxy‐containing acrylic copolymer of the highest concentration of PEGMA showed a desirable passivation effect on CB, and was found to lower the viscosity of the CB‐epoxy paste, leading to the well‐cured composite after heat treatment. The thick composite film prepared by employing the [CB/acrylic dispersant/epoxy] paste was built up on a Cu plate by a screen printing process followed by thermal curing. The dielectric properties of the 3.1 vol % CB‐filled epoxy film showed us high dielectric constant (Dk 4900) and rather low dissipation factor (Df 29%) at 1 MHz. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Controlled grafting of poly(vinyl acetate) onto starch via RAFT polymerization
Authors: Lu Derong , Xiao Congming , Sun Fei 
Published: November 2011

AbstractA structure‐exact starch‐based xanthate agent was prepared and used as chain transfer agent to mediate RAFT polymerization of vinyl acetate, which offered a convenient way to well control the structure and composition of starch‐g‐poly(vinyl acetate). The structures of the intermediate and the polymer were verified with FTIR and 1H‐NMR. Gel permeation chromatography measurement results indicated that the polymerization was performed as expected. It was found that the relationship between number average molecular weight and monomer conversion was linear. The polydispersity index of grafted side‐chain ranged from 1.19 to 1.53 and most of them were around 1.2. There was one more degradation stage appeared on the thermogravimetric analysis profile of starch‐g‐poly(vinyl acetate) than that of starch. TEM observation exhibited that the product was able to self‐assemble into micelles in aqueous solution, which suggested the copolymer was amphiphilic. Both the thermal and amphiphilic properties demonstrated the starch‐g‐poly(vinyl acetate) was successfully synthesized as well. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Convenient synthesis of sulfonamides from amines and p‐toluene sulfonyl chloride mediated by crosslinked poly(4‐vinylpyridine)
Authors: Zarchi Mohammad Ali Karimi , Aslani Mariam 
Published: November 2011

AbstractA general, mild, and convenient method has been developed for the synthesis of various N‐substituted and N, N‐disubstituted sulfonamides, as a class of sulfa drugs, from the corresponding amines and p‐toluene sulfonyl chloride in the presence of readily available crosslinked poly(4‐vinylpyridine) as a catalyst, base or polymeric substrates. The use of polymeric catalyst simplifies routine sulfonylation of amines because it eliminates the traditional purification. The polymer can be removed quantitatively and it can be regenerated and reused for several cycles without losing its activity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
The synergistic effect of aluminum hypophosphide and nanosilica on flame‐retarded ethylene–propylene–diene monomer rubber
Authors: Wang Zongtao , Zhang Xian , Bao Chao , Wang Qunyue , Qin Yong , Tian Xingyou 
Published: November 2011

AbstractThe influence of aluminum hypophosphide (AlHPi) and nanosilica on the flame‐retardant and mechanical property of ethylene–propylene–diene monomer (EPDM) rubber was evaluated by limiting oxygen index, and the value of tensile strength and elongation at break. The results show that the introduction of nanosilica into the EPDM/AlHPi blends can not only further improve the flame‐retardant property but also improve the tensile strength and elongation at break significantly, showing a synergistic effect between AlHPi and nanosilica. The flame‐retardant mechanism was further studied by X‐ray diffraction (XRD), thermogravimetric (TG) analysis, differential scanning calorimetry (DSC), and scanning electron microscope (SEM). The results of XRD and TG–DSC indicate that AlHPi will melt along with oxidation at about 337°C, which is helpful to full contact with nanosilica and to enhance the interaction between them; and will further recrystallize above 540°C, which is benefited to enhance the mechanical strength of char layer. The char morphological study by SEM shows that the char layer for the sample with both AlHPi and nanosilica is strong, more uniform and dense, and the scale of the holes in the char layer is smaller compared with the char layer of samples with AlHPi or nanosilica alone. The TG–DSC results show that the sample with both AlHPi and nanosilica has the weakest weight loss rate and heat release rate, compared with the samples with either of them, which is another evidence of the synergistic flame retardant effect between AlHPi and nanosilica. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Mechanical and structural characterizations of simultaneously aligned and heat treated PAN nanofibers
Authors: Ravandi Seyed Abdolkarim Hosseini , Sadrjahani Mehdi 
Published: November 2011

AbstractA simple and nonconventional electrospinning technique was employed for producing aligned polyacrylonitrile (PAN) nanofibers. A thermal zone was placed between syringe needles and collector in the electrospinning set up to obtain aligned and heat treated nanofibers. Suitable temperatures for heat treat process of PAN nanofibers was determined using differential scanning spectroscopy (DSC) technique. The influence of treatment temperature was investigated on morphology, internal structure and mechanical properties of collected PAN nanofibers. The average fiber diameter measured from SEM images exhibited decreasing trend at higher temperatures. FTIR spectra indicated no considerable difference between chemical structure of untreated and treated PAN nanofibers. Crystallization degree of PAN nanofibers calculated from WAXD patterns showed relatively low change with treatment temperature. Tenacity values of nanofiber bundles increased with increasing temperature while the extension values had an inverse trend. However, the modulus did not show a regular manner, but treated nanofibers had more modulus than untreated ones. The stress and modulus of PAN nanofibers increased to 112.9 MPa and 7.25 GPa at 270°C, respectively. Nanofibers treated at the highest temperature had the largest amount of crystallinity and strength. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Purification and biochemical characterization of glutathione S‐transferases from four field populations of Bactrocera dorsalis (Hendel) (Diptera: Tephritidae)
Authors: Hu Fei , Dou Wei , Wang Jing‐Jing , Jia Fu‐Xian , Wang Jin‐Jun 
Published: November 2011

AbstractGlutathione S‐transferases (GSTs) are a group of detoxification enzymes that catalyze the nucleophilic addition of glutathione to a wide variety of endogenous and xenobiotic compounds. In this study, GSTs were purified from four field populations of Bactrocera dorsalis with different insecticide susceptibilities by glutathione–agarose affinity chromatography. The populations were collected from Dongguan (DG) and Guangzhou (GZ) of the Guangdong Province, Haikou of the Hainan province (HN), and Kunming of the Yunnan province (YN), China. Differences in GST characteristics among the four populations were studied using purified enzyme samples through comparative SDS‐PAGE, kinetic, and inhibition experiments. The specific activities of the purified enzymes were similar, but the purification yield of the GZ population (31.54%) was the lowest. SDS‐PAGE analysis showed only one band at approximately 23 kDa for these four populations. Kinetic analyses showed that the affinities of the purified GSTs from the GZ and YN populations for 1‐chloro‐2.4‐dinitrobenzene (CDNB) were much higher than those of GSTs from the other two populations, whereas the HN population had the highest catalytic capability in terms of Vmax value. The optimum temperature for CDNB conjugation was 37°C and the optimum pH was 7.5 in all four populations. Inhibition kinetics showed that ethacrynic acid, diethyl maleate, tetraethylthiuram disulfide, curcumin, bromosulfalein, and β‐cypermethrin had excellent inhibitory effects on GSTs in the four populations of B. dorsalis, but the low inhibitory effects of malathion and avermectin did not differ between populations. These results suggest that GSTs may have a role in detoxification of β‐cypermethrin in B. dorsalis. © 2011 Wiley Periodicals, Inc.
Robust H2 Filtering for Discrete‐Time Markovian Jump Linear Systems
Authors: Liu Tao , Zhang Hao , Chen Qijun 
Published: November 2011

AbstractThis paper studies the problems of H2 filtering for discrete‐time Markovian jump linear systems with non‐accessible mode information. The objective is to design a less‐conservative mode‐independent H2 filter such that the filtering error system is stochastically stable. To this end, sufficient conditions for the existence of an upper bound of H2 norm are given in terms of linear matrix inequalities. With the introduction of a slack variable, a less‐conservative filter is derived. The proposed robust H2 filter design method is also applicable to cover the cases where the system matrices are subject to polytopic uncertainty, as well as the case where the transition probability matrix is subject to a given polytopic uncertainty. Application of the proposed method to three examples from the literature demonstrates the favorable performance of the proposed solution to existing approaches.
Robust Performance Controller Synthesis Based on Discrete‐Time Noncausal Linear Periodically Time‐Varying Scaling
Authors: Hosoe Yohei , Hagiwara Tomomichi 
Published: November 2011

AbstractThis paper is concerned with the technique called discrete‐time noncausal linear periodically time‐varying (LPTV) scaling for robust stability analysis and synthesis. It is defined through the lifting treatment of discrete‐time systems, and naturally leads to a sort of noncausal operation of signals. In the robust stability analysis of linear time‐invariant (LTI) systems, it has been shown that even static noncausal LPTV scaling induces some frequency‐dependent scaling when it is interpreted in the context of lifting‐free treatment. This paper first discusses in detail different aspects of the effectiveness of noncausal LPTV scaling, with the aim of showing its effectiveness in controller synthesis. More precisely, we study the robust performance controller synthesis problem, where we allow the controllers to be LPTV. As in the LTI robust performance controller synthesis problem, we tackle our problem with an iterative method without guaranteed convergence to a globally optimal controller. Despite such a design procedure, the closed‐loop H∞ performance is expected to improve as the period of the controller is increased, and we discuss how the frequency‐domain properties of noncausal LPTV scaling could contribute to such improvement. We demonstrate with a numerical example that an effective LPTV controller can be designed for a class of uncertainties for which the well‐known μ‐synthesis fails to derive even a robust stabilization controller.
CFD analysis of two‐phase turbulent flow in internal airlift reactors
Authors: Mohajerani Masroor , Mehrvar Mehrab , Ein‐Mozaffari Farhad 
Published: November 2011

AbstractThe hydrodynamic performance of three internal airlift reactor configurations was studied by the Eulerian–Eulerian k–ε model for a two‐phase turbulent flow. Comparative evaluation of different drag and lift force coefficient models in terms of liquid velocity in the riser and downcomer and gas holdup in the riser was highlighted. Drag correlations as a function of Eötvös number performed better results in comparison to the drag expressions related to Reynolds number. However, the drag correlation as a function of both Reynolds and Eötvös numbers fitted well with experimental results for the riser gas holdup and downcomer liquid velocity in configurations I and II. Positive lift coefficients increase the liquid velocity and decrease the riser gas holdup, while opposite results were obtained for negative values. By studying the effects of bubble size and their shape, the smaller bubbles provide a lower liquid velocity and a gas holdup. The effects of bubble‐induced turbulence and other non‐drag closure models such as turbulent dispersion and added mass forces were analysed. The gas velocity and gas holdup distributions, liquid velocity in the riser and downcomer, vectors of velocity magnitude and streamlines for liquid phase, the dynamics of gas holdup distribution and turbulent viscosity at different superficial gas velocities for different reactor configurations were computed. The effects of various geometrical parameters such as the draft tube clearance and the ratio of the riser to the downcomer cross‐sectional area on liquid velocities in the riser and the downcomer, the gas velocity and the gas holdup were explored. © 2011 Canadian Society for Chemical Engineering
Comparative kinetics of transesterification for biodiesel production from palm oil and mustard oil
Authors: Issariyakul Titipong , Dalai Ajay K. 
Published: November 2011

AbstractThe kinetics of palm oil and mustard oil transesterification are compared. Transesterification of palm oil and mustard oil using KOH as a catalyst was performed at various reaction temperatures ranging from 40 to 60°C. The reaction steps are reversible and transesterification is favoured at elevated temperatures. The reaction step of triglyceride to diglyceride is the rate determining step (RDS) that controls kinetics of overall transesterification with activation energies of 30.2 and 26.8 kJ/mol for palm oil and mustard oil transesterification, respectively. It is found that percentage of saturated compounds play a vital role on transesterification kinetics. © 2011 Canadian Society for Chemical Engineering
Multicomponent mass diffusion in porous pellets: Effects of flux models on the pellet level and impacts on the reactor level. Application to methanol synthesis
Authors: Solsvik Jannike , Jakobsen Hugo A. 
Published: November 2011

AbstractA heterogeneous model has been derived for a fixed packed‐bed reactor producing methanol. Several closures for the intra‐particle mass diffusion fluxes; Maxwell–Stefan, Wilke, dusty gas and Wilke–Bosanquet, have been compared on the level of the catalyst pellet and the impacts of the different particle flux closures on the reactor performance are investigated. A preparatory study of the transport phenomena on the pellet level is recommended prior to any large‐scale reactor simulation to determine what are the rate determining transport mechanisms. Hence, if Knudsen diffusion is apparent on the level of the pellet, a combined bulk and Knudsen diffusion model should naturally be used in the reactor simulations as well, because Knudsen diffusion can influence significantly on the reactor conversion. Minor differences are observed between the diffusion flux models on both pellet and reactor level. Hence, for the reactor operation conditions applied in this study, the Wilke model is a good approximation to the rigorous Maxwell–Stefan model, and similarly, the Wilke–Bosanquet model is an appropriate model to use in replacement for the dusty gas model. Moreover, variable pressure and viscous flow can be neglected in the pellet model, as the effect of these contributions are not visible at neither pellet or reactor level. © 2011 Canadian Society for Chemical Engineering
Triorganyl‐ and Diorganyloxozirconium Hydridoborates – Synthesis and Structures
Authors: Knizek Jörg , Nöth Heinrich , Schmidt‐Amelunxen Martin 
Published: November 2011

AbstractThe reactions of Zr(OBu)4 and Zr(OEt)4 with H3B·THF in THF led to HB(OR)2 and B(OR)3, but no zirconium tetrahydroborate [(RO)4–nZr(BH4)n] could be isolated. On the contrary, the reactions of [tBu3CO]4–nZrCln and [tBu3SiO]4–nZrCln with LiBH4 generated the tetrahydroborates [(RO)3Zr(BH4)] and [(RO)2Zr(BH4)2]. These can be used to produce by hydroborate exchange dihydridodiorganyl borates [(RO)4–nZr(H2BC8H14)n] and byproducts. The structures of the new zirconium hydridoborates have been determined by X‐ray crystallography. Compound [(tBu3CO)3Zr(H2BC8H14)] shows site‐disordered dihydroborate units with agostic Zr–H–C interactions, while [(tBu3SiO)2Zr(H2BC8H14)2] is quite symmetric (C2/c). The corresponding tetrahydridoborates possess in most cases μ31‐bonded ZrH3BH groups.
Exploitation of detergent thermodynamics in the direct solubilization of myelin membrane proteins for two‐dimensional gel electrophoresis for proteomic analysis
Authors: Nair Sreepriya , Xavier Tessy , Satheesh Kumar Madathiparambil Kumaran , Saha Sharmistha , Menon Krishnakumar N. 
Published: November 2011

AbstractPerforming 2‐DE of lipid‐rich multilamellar membranes like myelin is a cumbersome task. However, for understanding its molecular organization and changes during diseases, identification of proteins of myelin is essential. Although the 2‐D‐proteomic approach of myelin has been employed to understand the myelin proteome, representation of myelin proteins in its entirety is still a challenge. 2‐DE profiling of myelin proteins is very important for the detection of immuno‐reactivity to myelin proteins from various biological fluids following Western blotting in diseases like multiple sclerosis. Here we developed a novel approach by exploiting the thermodynamic principles behind detergent‐mediated solubilization of myelin membranes without any conventional processing of myelin involving precipitation of myelin proteins. We show that the addition of myelin to ASB‐14‐4 resulted in significant increase in protein representation of myelin in 2‐DE compared with the addition of ASB‐14‐4 to myelin. Moreover, the number and resolution of spots are significantly higher in myelin to ASB‐14‐4 strategy than other strategies of myelin sample processing such as ASB‐14‐4 to myelin or ethanol or acetone or methanol–ammonium acetate precipitation of myelin proteins. In addition, the step involves no precipitation that selective removal of any proteins as a result of precipitation is nil and a qualitative representation of myelin proteins in a 2‐D gel is achieved.
Online enzymatic sequencing of glycans from Trastuzumab by phospholipid‐assisted capillary electrophoresis
Authors: Archer‐Hartmann Stephanie A. , Crihfield Cassandra L. , Holland Lisa A. 
Published: November 2011

AbstractCE separations of glycans taken from the cancer drug, Trastuzumab (Herceptin®), were accomplished using phospholipid additives. Glycans were labeled with 1‐aminopyrene‐3,6,8‐trisulfonic acid and were separated with efficiencies as high as 510 000 theoretical plates in a 60.2 cm 25 μm id fused‐silica capillary. The thermally tunable phospholipid was loaded into the capillary when it possessed a viscosity similar to that of water. The temperature was increased, and the separations were performed when the material exhibited higher viscosity. Enzymes were integrated into the separation with the phospholipid additive. Neuraminidase, β1‐4 galactosidase, and β‐N‐acetylglucosaminidase were injected into the capillary without covalent modification and used for enzyme hydrolysis. Exoglycosidase enzymes cleaved the terminal glycan residues. The glycan sequence could be verified based on enzyme specificity. Neuraminidase was used to determine total glycan content of the low‐abundance glycans containing sialic acid. β1‐4 Galactosidase and β‐N‐acetylglucosaminidase were used sequentially in‐capillary, to determine the structure of the high‐abundance glycans.