bluuebunny/crossref_metadata_2025_split huggingface dataset:
Corrosion behavior of titania films coated by liquid‐phase deposition on AISI304 stainless steel substrates
Authors: Cai Yongwei , Liu Mingyan 
Published: June 2011

AbstractFouling deposition and localized corrosion on the heat‐transfer surfaces of the stainless steel equipments often simultaneously exist, which can introduce additional thermal resistance to heat‐transfer and damage heat‐transfer surfaces. It is a good anticorrosion way to coat a barrier layer of certain materials on the metal surface. In this article, the TiO2 coatings with nanoscale thicknesses were obtained by liquid‐phase deposition method on the substrates of AISI304 stainless steel (ASS). The coating thickness, surface roughness, surface morphology, crystal phase, and chemical element were characterized with the film thickness measuring instrument, roughmeter, atomic force microscopy, field emission scanning electron microscopy, X‐ray diffraction, and energy‐dispersive X‐ray spectroscopy analyzer, respectively. Corrosion behavior of the TiO2 coatings was evaluated by potentiodynamic polarization, cyclic voltammograms scanning, and electrochemical impedance spectroscopy tests with the mixed corrosion solution composed of 3.5 wt. % NaCl and 0.05 M NaOH. It is shown that the TiO2 coating is composed of the nanoparticles with smooth, crack‐free, dense, and uniform surface topography; the roughness of coating surface increases slightly compared with that of the polished ASS substrate. The anatase‐phase TiO2 coatings are obtained when sintering temperature being varied from 573.15 to 923.15 K and exhibit better anticorrosion behavior compared with ASS surfaces. The corrosion current density decreases and the polarization resistance increases with the increase of the coating thickness. The corrosion resistance of the TiO2 coatings deteriorates with the increase of the corrosion time. The capacitance and the resistance of the corrosion product layer between the interface of the ASS substrate and the TiO2 coating are found after the corrosion time of 240 h. A corrosion model was introduced, and a possible new explanation on the anticorrosion mechanisms of the TiO2 coating was also analyzed. The corrosion mechanism of the TiO2 coating might comply with the multistage corrosion process. © 2011 American Institute of Chemical Engineers AIChE J, 58: 1907–1920, 2012
Demography of squirrel monkeys (Saimiri sciureus) in captive environments and its effect on population growth
Authors: Zimbler‐DeLorenzo Heather S. , Dobson F. Stephen 
Published: June 2011

AbstractUnderstanding which life‐history variables have the greatest influence on population growth rate has great ecological and conservation importance. Applying models of population regulation and demographic mechanisms can aid management and conservation of both wild and captive populations. By comparisons of sensitivity, elasticity, and life‐table response analyses, we identified demographic processes that were most likely to produce changes in population size (via prospective analyses) and the traits that actually influenced population changes (via retrospective analyses) among sexes, zoological facilities, and generations of captive squirrel monkey populations (Saimiri sciureus). Variation in life‐history traits occurs within each group analyzed. Those traits that vary the most include age at maturity, age at last reproduction, and fertility. Zoos with increasing population growth rates maintain earlier ages of maturity, later ages of last reproduction, high rates of juvenile and adult survival, and most importantly greater fertility, reflecting shorter inter‐birth intervals. Using prospective analyses, juvenile and adult survivals were predicted to be demographic traits with the greatest effect on population growth. Surprisingly, and despite predictions, retrospective analyses revealed that fertility was the life‐history characteristic trait that contributed the most to changes in population size. Am. J. Primatol. 73:1041–1050, 2011. © 2011 Wiley‐Liss, Inc.
Synthesis and characterization of poly(urethane‐ether)s from calcium salt of p‐hydroxybenzoic acid
Authors: Nair Priya A. , Ramesh P. 
Published: June 2011

AbstractThe synthesis and characterization of calcium‐containing poly(urethane‐ether)s, having ionic links in the main chain, is reported. Calcium salt of p‐hydroxybenzoic acid (HBA‐Ca) was prepared from p‐hydroxybenzoic acid (HBA) and used as the chain extender in the preparation of calcium‐containing poly(urethane‐ether)s. Poly(urethane‐ether)s, having two different compositions, were prepared by varying the mole ratios of poly(tetramethylene glycol), hexamethylene diisocyanate, and HBA‐Ca. The synthesized poly(urethane‐ether)s were characterized by infrared spectroscopy, thermogravimetric analysis, and dynamic mechanical analysis. The presence of calcium in the polymer chain was confirmed by energy‐dispersive X‐ray analysis. The inherent viscosity of metal‐containing polymers decreased with the increase in the metal content of the polymer. The introduction of metal into the polymer lowers the thermal stability of the polymers as indicated by the decreased initial decomposition temperature. The glass transition temperature (Tg) and the storage modulus of the metal‐containing polymers increase with the increase in metal content presumably due to the formation of physical crosslink's in the polymer. From the mechanical studies of the polymer, it was observed that the metal‐containing polymers exhibit high tensile strength and modulus. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
The effect of clay type and of clay–masterbatch product in the preparation of polypropylene/clay nanocomposites
Authors: Rodríguez‐Llamazares Saddys , Rivas Bernabé L. , Pérez Mónica , Perrin‐Sarazin Florence , Maldonado Alvaro , Venegas Carola 
Published: June 2011

AbstractClay containing polypropylene (PP) nanocomposites were prepared by direct melt mixing in a twin screw extruder using different types of organo‐modified montmorillonite (Cloisite 15 and Cloisite 20) and two masterbatch products, one based on pre‐exfoliated clays (Nanofil SE 3000) and another one based on clay–polyolefin resin (Nanomax‐PP). Maleic anhydride‐grafted polypropylene (PP‐g‐MA) was used as a coupling agent to improve the dispersability of organo‐modified clays. The effect of clay type and clay–masterbatch product on the clay exfoliation and nanocomposite properties was investigated. The effect of PP‐g‐MA concentration was also considered. Composite morphologies were characterized by X‐ray diffraction (XRD), field emission gun scanning electron microscopy (FEG‐SEM), and transmission electron microscopy (TEM). The degree of dispersion of organo‐modified clay increased with the PP‐g‐MA content. The thermal and mechanical properties were not affected by organo‐modified clay type, although the masterbatch products did have a significant influence on thermal and mechanical properties of nanocomposites. Intercalation/exfoliation was not achieved in the Nanofil SE 3000 composite. This masterbatch product has intercalants, whose initial decomposition temperature is lower than the processing temperature (T ∼ 180°C), indicating that their stability decreased during the process. The Nanomax‐PP composite showed higher thermal and flexural properties than pure PP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Structure characterization of cold drawn high density polyethylene thin film
Authors: Fouda I. M. , El‐Tonsy M. M. , Seisa E. A. , Felfel R. M. 
Published: June 2011

AbstractThis work throws light to study the changes of optical birefringence for cold drawn high density polyethylene (HDPE) thin film at different stresses. A stress–strain device connected to a scattering optical system was used to investigate the dynamical behavior of opto‐mechanical properties at room temperature (27°C ± 1°C). Some structural parameters, optical and mechanical orientation factors, f(θ), f2(θ), f4(θ), f6(θ), Fav, P2(θ), P4(θ), fc, and fm, were calculated. Also, the distribution segments at an angle (θ), the number of random links per chain (N1), the number of chains per unit volume (Nc), and the average work per chain W′ were calculated. The average value of the maximum birefringence was evaluated. The obtained studies demonstrate changes to the molecular orientation functions and evaluated micro structural parameters as a result of the applied cold‐drawing process on (HDPE) thin film. Relationships between the calculated parameters and draw ratios were presented for illustration. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Greatly improved adsorption of N‐methylated modified macroporous cross‐linked polyacrylamide toward tannin from aqueous solution
Authors: Xu Mancai , Hu Liping , Huang Jianhan , Huang Kelong 
Published: June 2011

AbstractMacroporous cross‐linked poly(N‐methylacrylamide) (PMAM) was prepared and the adsorption behaviors of PMAM toward tannin from aqueous solution was studied in comparison with polyacrylamide (PAM). The swollen property indicated that PMAM had a higher hydrophobicity than PAM while the adsorption showed that PMAM had a greatly improved adsorption toward tannin. The adsorption data could be fitted well by Freundlich model and the values of the thermodynamic parameters of PMAM toward tannin were more negative than PAM. The multiple hydrogen bonding and hydrophobic interaction between PAM/PMAM and tannin were shown to be responsible for the adsorption, whereas a stronger hydrogen bonding and a higher hydrophobicity of PMAM had a contribution to the greatly improved adsorption of PMAM toward tannin. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Heavy metals removal from solution by polyaniline/palygorskite composite
Authors: Kong Yong , Wei Jingxuan , Wang Zhiliang , Sun Tao , Yao Chao , Chen Zhidong 
Published: June 2011

AbstractBatch adsorption experiments were carried out to remove heavy metal ions such as Cu (II), Ni (II), Cd (II), and Cr (VI) from single‐metal solutions using a polyaniline/palygorskite (PP) composite. Different parameters affecting the adsorption capacity such as contact time and pH of the solution have been investigated. The structural characteristics of the PP composite were studied in this work. Atomic absorption spectroscopy was used for the measurement of heavy metal contents, and the adsorption capacity (qe) calculated were 114 mg Cu (II) g−1, 84 mg Ni (II) g−1, 56 mg Cd (II) g−1, and 198 mg Cr (VI) g−1 under optimal conditions. The removal of the metal ions from solutions was assigned to chelation, ionic exchange, and electrostatic attraction. Data from this study proved that the novel organic/inorganic composite presents great potential in the recovery and elimination of noble or heavy metal ions from industrial wastewater. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Effect of silica modification on the chemical interactions in NBR‐based composites
Authors: Lopez Juan F. , Perez Leon D. , Lopez Betty L. 
Published: June 2011

AbstractFillers are modified with the purpose of increasing their interactions with polymer matrices; however it is necessary to determine the impact that those modifications have on the composite performance and morphology. In this work, the strength of the chemical interactions between silica with different chemical characteristics and acrylonitrile butadiene rubber (NBR) is studied by infrared spectroscopy measuring the increase of C≡N fundamental vibration frequency and by density functional theory (DFT) and ab initio methods. The results from the chemical interactions were compared with the morphology and thermal behavior of composites based on those components. Good agreement between the molecular parameters estimated theoretically and the shifting of the absorption frequency due to C≡N stretching was observed. Morphological studies revealed that the steric hindrance exerted by modifier moieties on silica surface favors the filler dispersion. Functional groups on the surface strongly interacting with NBR play an important role in the compatibility of immiscible blends of NBR copolymers studied in this work. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Isoconversional and thermal methods of kinetic analysis of 2,4‐dihydroxybenzophenone copolymer resin
Authors: Gurnule Wasudeo B. , Butoliya S. S. 
Published: June 2011

AbstractA copolymer (2,4‐DHBPOF) synthesized by the condensation of 2,4‐dihydroxybenzophenone and oxamide with formaldehyde in the presence of acid catalyst with varying the molar proportions of the reacting monomer. Composition of the copolymer has been determined by elemental analysis. The copolymer has been characterized by UV–visible, FTIR, and 1H NMR spectroscopy. The morphology of synthesized copolymer was studied by scanning electron microscopy (SEM). The activation energy (Ea) and thermal stability calculated by using Sharp‐Wentworth, Freeman–Carroll, and Freidman's method. Thermogravimetric analysis (TGA) data were analyzed to estimate the characteristic thermal parameters. Freeman–Carroll and Sharp Wentworth methods have been used to calculate activation energy and thermal stability. The activation energy (Ea) calculated by using the Sharp‐Wentworth has been found to be in good agreement with that calculated by Freeman–Carroll method. Thermodynamic parameters such as free energy change (ΔF), entropy change (ΔS), apparent entropy change (S*), and frequency factor (Z) have also been evaluated based on the data of Freeman–Carroll method. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Injectable thermosensitive hydrogels for intra‐articular delivery of methotrexate
Authors: Miao Bolong , Song Cunxian , Ma Guilei 
Published: June 2011

AbstractIntra‐articular drug delivery is the preferred approach for targeting pharmacologic treatment directly at the joints to reduce undesirable side effects associated with systemic drug delivery. In this study, a controlled delivery system of methotrexate (MTX) based on injectable thermosensitive poly(ε‐caprolactone)‐poly(ethylene glycol)‐poly(ε‐caprolactone) (PCL‐PEG‐PCL, PEP) hydrogels was developed for the intra‐articular drug delivery. The thermosensitive PEP copolymers were prepared by ring‐opening polymerization. The synthesized PEP copolymers were characterized for their structure, composition, and the sol‐to‐gel transition. The in vitro MTX release from the PEP hydrogels was studied. MTX plasma concentration following intra‐articular injection into healthy rats was determined by HPLC. Biocompatibility was confirmed by histology analysis after the intra‐articular injection. The synthesized PEP copolymers aqueous solutions formed in situ gel rapidly after the injection. PEP hydrogels showed the ability to control the release of incorporated MTX. Following intra‐articular injection, the PEP hydrogels decreased the clearance rate of MTX in the joint cavity. The maximum plasma concentrations of MTX in rats injected with free MTX were threefold higher than that of the groups injected with MTX hydrogels. These results suggest that the intra‐articular delivery of the PEP hydrogels may be a viable strategy for the controlled release of drugs for treating arthritis diseases. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effects of processing route on morphology and mechanical behavior of polypropylene in equal channel angular extrusion
Authors: Wang Tinglan , Tang Songchao , Chen Jianding 
Published: June 2011

AbstractChanges of morphology and mechanical behavior of isotactic polypropylene (iPP) due to equal channel angular extrusion (ECAE) were investigated. The iPP specimens were processed for up to two passes in the same direction (route A), with the specimens rotate 180°around loading axis after the previous pass (route C). The macroscopic observation showed that high level of shear strain is introduced in iPP extruded twice in route A. Reflected optical microscopy revealed that the original spherulites are elongated into ellipsoidal shape along the shear direction in route A, and the recovery of the spherulitic shape occurred in iPP extruded in route C. X‐ray diffraction results and the dynamic mechanical analysis showed that the crystalline and amorphous phase are prone to orientation more favorably via route A than route C. The increase of the dynamic storage modulus (E′) indicated that iPP becomes stiffer than other samples when extruded twice in route A. Izod impact testing results demonstrated that the ECAE‐deformed spherulites influence the crack propagation direction. The impact strength of iPP is greatly improved to 490.5 J/m after processed twice in route A, 10 times of that of un‐deformed reference sample. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Improvement of the Cytotoxicity and Tumor Selectivity of Glycyrrhetinic Acid by Derivatization with Bifunctional Aminoacids
Authors: Csuk René , Schwarz Stefan , Kluge Ralph , Ströhl Dieter 
Published: June 2011

AbstractGlycyrrhetinic acid (GA) is a major ingredient of the dried extract of licorice roots; its antitumor activity is low compared to other members of the triterpenoic family. For example, oleanolic acid, betulin or betulinic acid are more cytotoxic with a pronounced activity for tumor cells. GA, however, is easily to earn, cheap and shows apoptotic effects on tumor cells – like the other triterpenoic acids. These facts bring GA and derivatives in the focus of our scientific interest. Here we tried to improve the poor cytotoxicity of GA by simple derivatization. Thus, we selected various glutamyl and aspartyl substituents for the synthesis of C(3) esters of GA methyl ester. A short (3‐5 steps) synthesis was elaborated that allowed to access more effective compounds. One compound, methyl 3β 3‐(O‐benzyl‐L‐glutamyl)‐11‐oxo‐olean‐12‐en‐30‐oate (5), having a glutamyl substituent with a benzyl protected side chain showed up to 67‐fold higher cytoxicity and an up to 140‐fold better selectivity towards tumor cells than parent GA. All compounds were evaluated by a sulforhodamine B assay as well as by a trypan blue test and extra acridine orange/ethidium bromide tests for apoptosis.
Synthesis, Structure, and Reactivity of Hydridoiridium Complexes Bearing a Pincer‐Type PSiP Ligand
Authors: Fang Hongyun , Choe Yoong‐Kee , Li Yonghua , Shimada Shigeru 
Published: June 2011

AbstractA series of iridium tetrahydride complexes [Ir(H)4(PSiP‐R)] bearing a tridentate pincer‐type bis(phosphino)silyl ligand ([{2‐(R2P)C6H4}2MeSi]−, PSiP‐R, R=Cy, iPr, or tBu) were synthesized by the reduction of [IrCl(H)(PSiP‐R)] with Me4N⋅BH4 under argon. The same reaction under a nitrogen atmosphere afforded a rare example of thermally stable iridium(III)–dinitrogen complexes, [Ir(H)2(N2)(PSiP‐R)]. Two isomeric dinitrogen complexes were produced, in which the PSiP ligand coordinated to the iridium center in meridional and facial orientations, respectively. Attempted substitution of the dinitrogen ligand in [Ir(H)2(N2)(PSiP‐Cy)] with PMe3 required heating at 150 °C to give the expected [Ir(H)2(PMe3)(PSiP‐Cy)] and a trigonal bipyramidal iridium(I)–dinitrogen complex, [Ir(N2)(PMe3)(PSiP‐Cy)]. The reaction of [Ir(H)4(PSiP‐Cy)] with three equivalents of 2‐norbornene (nbe) in benzene afforded [IrI(nbe)(PSiP‐Cy)] in a high yield, while a similar reaction of [Ir(H)4(PSiP‐R)] with an excess of 3,3‐dimethylbutene (tbe) in benzene gave the CH bond activation product, [IrIII(H)(Ph)(PSiP‐R)], in high yield. The oxidative addition of benzene is reversible; heating [IrIII(H)(Ph)(PSiP‐Cy)] in the presence of PPh3 in benzene resulted in reductive elimination of benzene, coordination of PPh3, and activation of the CH bond of one aromatic ring in PPh3. [IrIII(H)(Ph)(PSiP‐R)] catalyzed a direct borylation reaction of the benzene CH bond with bis(pinacolato)diboron. Molecular structures of most of the new complexes in this study were determined by a single‐crystal X‐ray analysis.
The new IRSOL solar telescope control system
Authors: Küveler G. , Dao V.D. , Ramelli R. 
Published: June 2011

AbstractWe would like to present a new control system for the solar telescope now in operation at the Swiss institute, Istituto Ricerche Solari Locarno (IRSOL). The control software is multi‐client capable, and optionally uses the primary image of the sun projected on a position sensor or the axis encoder for guiding. The hardware and software consist of three completely separate levels, which communicate with each other via ASCII commands. We shall describe the general principles implemented in the course of the development. We consider it important that this text is also applicable to other astronomical device controls. Therefore we explain our specific solution next to general principles (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Alleviation of catastrophic quenching in solar dynamo model with nonlocal alpha‐effect
Authors: Kitchatinov L.L. , Olemskoy S.V. 
Published: June 2011

AbstractThe nonlocal alpha‐effect of Babcock‐Leighton type is not prone to the catastrophic quenching due to conservation of magnetic helicity. This is shown with a dynamo model, which jointly applies the nonlocal alpha‐effect, the diamagnetic pumping, and dynamical equation for the magnetic alpha‐effect. The same model shows catastrophic quenching when the alpha‐effect is changed to its local formulation. The nonlocal model shows a preferred excitation of magnetic fields of dipolar symmetry, which oscillate with a period of about ten years and have a toroidal‐to‐polar fields ratio of about a thousand (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Speckle observations with PISCO in Merate: X. Astrometric measurements of visual binaries in 2009
Authors: Scardia M. , Prieur J.‐L. , Pansecchi L. , Argyle R.W. , Sala M. 
Published: June 2011

AbstractWe present relative astrometric measurements of visual binaries, made in 2009 with the speckle camera PISCO at the 102 cm Zeiss telescope of Brera Astronomical Observatory, in Merate. Our observing list contains orbital couples as well as binaries whose motion is still uncertain. We obtained 345 new measurements of 259 objects, with angular separations in the range 0.″18–4.″6, and an average accuracy of 0.″011. The mean error on the position angles is 0.°6. Most of the position angles were determined without the usual 180° ambiguity with the application of triple‐correlation techniques and/or by inspection of the long integration files. We have found a possible new close component for ADS 2377, which would be a new quadruple star system. We also present new revised orbits for ADS 8035, 9982, 11484, and MLR 198, partly derived from those observations, and infer estimated values for the masses of those systems that are compatible with the spectral types (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Water in star‐forming regions with Herschel
Authors: Kristensen L.E. , van Dishoeck E.F. 
Published: June 2011

AbstractThe Herschel Space Observatory is well suited to address several important questions in star‐ and planet formation, as is evident from its first year of operation. This paper focuses on observations of water, a key molecule in the physics and chemistry of star‐formation. In the WISH Key Program, a comprehensive set of water lines is being obtained with the HIFI and PACS instruments toward a large sample of well‐characterized protostars, covering a wide range of luminosities and evolutionary stages. Lines of H2O, CO and their isotopologues, as well as chemically related hydrides, [O I] and [C II] are observed. Together, the data determine the abundance of water in cold and warm gas, reveal the entire CO ladder up to 4000 K above ground, elucidate the physical processes responsible for the warm gas (passive heating, UV or X‐ray‐heating, shocks), quantify the main cooling agents, and probe dynamical processes associated with forming stars and planets (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)