bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, characterization, and properties of amphiphilic block copolymer of acrylamide‐styrene by self‐emulsifying microemulsion method
Authors: Ge Zhen , Luo Yunjun 
Published: June 2009

AbstractThe copolymerization system of acrylamide (AM) and styrene (St) was acquired by using amphiphilic block copolymer PAM‐b‐PSt with lower molecular weight as polymeric surfactant, and then the microemulsion phase diagram was drawn. The appropriate copolymerization systems were chosen in the phase diagram, and higher molecular weight amphiphilic block copolymers PAM‐b‐PSt were prepared by self‐emulsifying microemulsion method. The chemical composition and structure of the products were analyzed by FTIR, 1H‐NMR, 13C‐NMR, GPC, and UV; the block structure of products was characterized by DSC, and the hydrophobic association property of the products was studied by the fluorescence probe and rotating viscosity measurement. The results showed that O/W microemulsion was also acquired by using the polymeric surfactant; 3 g polymeric surfactant was only used to disperse 0.25 g St into aqueous solution, which showed higher emulsifying efficiency. At the same time, the use of self‐emulsifying microemulsion copolymerizing system can avoid back treatment of small molecular surfactant and the purified block polymer was prepared in one step; the prepared copolymers have good hydrophobic association properties and their aqueous solution showed evident viscosity increment. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Studies on synthesis of modified epoxidized novolac resin from renewable resource material for application in surface coating
Authors: Yadav Ranjana , Awasthi Poonam , Srivastava Deepak 
Published: June 2009

AbstractFive blend samples of cardanol‐based epoxidized novolac resin containing varying concentrations of carboxyl‐terminated poly(butadiene‐co‐acrylonitrile) (CTBN) ranging between 0 and 25 wt % with an interval of 5 wt % were prepared. The epoxidized novolac resin (ECF) was synthesized from the epoxidation of cardanol‐based novolac‐type phenolic resin (CF) with molar excess of epichlorohydrin (i.e., about 10 mol at 120°C in basic medium). The CF resin was synthesized with a molar ratio of 1 : 0.5 of CF using dicarboxylic acid catalyst such as succinic acid at 120°C for 5 h. The pure epoxy and its blend were cured with stoichiometric amounts of polyamine curing agent. The formation of various products during the synthesis of cardanol‐based novolac resin, epoxidized novolac resin, and blending of epoxidized novolac resin with CTBN have been studied by Fourier transform infrared (FTIR) spectroscopic analysis. Further, a reaction mechanism for the step‐growth reaction was proposed on the basis of the results of FTIR analysis. Also, the structures of CF and ECF were proposed on the basis of the results of nuclear magnetic resonance and MALDI‐TOF mass spectroscopic analysis along with gel permeation chromatographic (GPC) analysis. GPC analysis resulted in Mn of 670 gmol−1. The blend sample having 15 wt % CTBN concentration showed minimum cure time, whereas the presence of CTBN in blend systems showed marginal change in the values of ΔH. A clear‐cut two‐step mass loss in dynamic thermogravimetric trace of unmodified and CTBN‐modified systems was observed. Thermal stability of the blend sample containing 15 wt % CTBN into the pure epoxy resin was the highest among all other prepared systems. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Formation of a bicontinuous structure membrane of polyvinylidene fluoride in diphenyl carbonate diluent via thermally induced phase separation
Authors: Lin Yakai , Tang Yuanhui , Ma Hengyu , Yang Jian , Tian Ye , Ma Wenzhong , Wang Xiaolin 
Published: June 2009

AbstractDiphenyl carbonate was used as a diluent to prepare microporous polyvinylidene fluoride (PVDF) membrane via thermally induced phase‐separation method. The liquid–liquid phase‐separation phenomenon was found in PVDF/diphenyl carbonate system during the thermally induced phase‐separation process. The monotectic point of this system appeared at a high polymer concentration approximately 56 wt %. This suggested that PVDF membrane with a bicontinuous or cellular structure could be obtained when the PVDF concentration was less than this point value. The effects of polymer concentration and quenching temperature on the membrane structure, porosity, and tensile strength were also investigated. The results showed that low polymer concentration and high quenching temperature led to a large pore size membrane. The tensile strength of the membrane increased with increase in the polymer concentration, but the porosity of the membrane decreased. On condition that the PVDF concentration was higher than 60 wt %, only polymer crystallization occurred and a typical compact spherulitic structure was obtained. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Properties of cotton fabrics treated by protease and its multienzyme combinations
Authors: Kalantzi Styliani , Mamma Diomi , Kalogeris Emmanuel , Kekos Dimitris 
Published: June 2009

AbstractA commercial serine‐type protease preparation (Alcalase) was examined as a scouring agent for cotton fabrics. Application of the enzyme induced moderate changes in the composition of fibers that were mainly associated with the removal of protein and waxes. The relationship between the compositional modifications and structural transformations, which were reflected in the crystallinity index of the bioscoured cotton fibers, was demonstrated. The protease‐treated textiles displayed superior whiteness and outstanding compressional resilience but exhibited a poor hydrophilicity and dyeing capacity. One‐step scouring at neutral conditions, where proteolytic activity was supported by multienzyme combinations, could generate textiles with sufficient water absorbency and advanced performance. The implementation of the appropriate scouring conditions (concentration and combination of enzymes) could form fabrics with the desired physicochemical and micromechanical properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis of novel poly(ether ketone diphenyl ketone ether ketone ketone)s by electrophilic Friedel–Crafts solution polycondensation
Authors: Cai Mingzhong , Xi Qin , Ding Nengwen , Song Cai‐Sheng 
Published: June 2009

Abstract4,4′‐Bis(4‐phenoxybenzoyl)diphenyl was prepared by the Friedel–Crafts reaction of 4‐bromobenzoyl chloride and diphenyl followed by condensation with potassium phenoxide. Novel aromatic poly(ether ketone diphenyl ketone ether ketone ketone)s were obtained by the electrophilic Friedel–Crafts solution copolycondensation of 4,4′‐bis(4‐phenoxybenzoyl)diphenyl with a mixture of isophthaloyl chloride and terephthaloyl chloride over a wide range of isophthaloyl chloride/terephthaloyl chloride molar ratios in the presence of anhydrous aluminum chloride and N‐methylpyrrolidone in 1,2‐dichloroethane. The influence of the reaction conditions on the preparation of the copolymers was examined. The copolymers were characterized with different physicochemical techniques. Because of the incorporation of diphenyl, the resulting copolymers exhibited outstanding thermal stability. The glass‐transition temperatures were above 174°C, the melting temperatures were above 342°C, and the 5% weight loss temperatures were above 544°C in nitrogen. All these copolymers were semicrystalline and insoluble in organic solvents. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Studies on the electrospun submicron fibers of SIS and its mechanical properties
Authors: Feng Shu‐Qin , Shen Xin‐Yuan , Fu Zhong‐Yu , Ji Ya‐Li 
Published: June 2009

AbstractThe submicron fibers were prepared via electrospinning the styrene–isoprene–styrene (SIS) triblock copolymer from a pure solvent of tetrahydrofuran (THF) and a mixed solvent of THF and N, N‐dimethylformamide (DMF). The addition of DMF to THF resulted in a beneficial effect on the fiber formation and the electrospinnability. The obtained results revealed that the fibers were only formed in a narrow solution concentration range of 8–15 wt %; the morphology, diameter, structure, and mechanical performance of as‐spun fibers from PS and SIS solutions were affected by the composition weight ratio and the solution properties; and those from the solution at the intermediate concentration of 10 wt % exhibited a maximum tensile strength and strain at break. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis of poly(methyl methacrylate) via reverse atom transfer radical polymerization catalyzed by FeCl3/lactic acid
Authors: Zhou Wenying , Chen Hou , Liang Ying , Yu Mengmeng , Chen Lichun 
Published: June 2009

AbstractReverse atom transfer radical polymerization (RATRP) of methyl methacrylate (MMA) with azobisisobutyronitrile (AIBN)/FeCl3/lactic acid as initiating system was successfully carried out in N,N‐dimethylformamide (DMF) for the first time. Kinetics as well as molecular weight distribution data indicated towards the controlled nature of polymerization. The polymerization not only showed the best control of molecular weight and its distribution but also provided a rather rapid reaction rate with the molar ratio of [MMA]:[AIBN]:[FeCl3]:[lactic acid] = 300 : 1 : 1 : 2. The polymerization rate increased with increasing the polymerization temperature. The apparent activation energy was calculated to be 47.90 kJ/mol. The rate of polymerization in DMF was faster than that in acetonitrile, cyclohexanone, toluene, and xylene. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Modulating the mechanical properties of poly(diol citrates) via the incorporation of a second type of crosslink network
Authors: Zhao Haichao , Ameer Guillermo A. 
Published: June 2009

AbstractNovel citric acid‐based polyesters were synthesized by condensation of citric acid, 1,8‐octanediol, and unsaturated monomers such as glycerol 1,3‐diglycerolate diacrylate and bis(hydroxypropylfumarate). Under the synthesis conditions used, the crosslinked elastomeric network exhibited a wide range of mechanical properties. The mechanical properties of acrylated elastomers ranged from 7.4 to 75.9 MPa for Young's modulus, 2.8 to 15.7 MPa for ultimate tensile stress, and 86 to 133% for elongation at break. The mechanical properties of fumarate‐containing elastomers ranged from 16.4 to 38.3 MPa for Young's modulus, 5.5 to 10.2 MPa for ultimate tensile stress, and 218 to 260% for elongation at break, which depended on the content of 1‐vinyl‐2‐pyrrolidinone. Addition of a secondary crosslink network is a viable method to increase the range of mechanical properties of citric acid‐based biodegradable elastomers. The glass transition temperature (Tg) of the elastomers is between −12.7 and −1.6°C, confirming that all the elastomers are in a rubbery state at room temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effect of nanofillers on carboxymethyl cellulose/hydroxyethyl cellulose hydrogels
Authors: Dai Qizhou , Kadla John F. 
Published: June 2009

AbstractThe effect of hydrophilic nanoparticles (oxidized cellulose nanocrystals (CNC) and montmorillonite nanoclay) on the properties of a sodium carboxymethylcellulose (CMC)/hydroxyethylcellulose (HEC) hydrogel system was investigated. Visually, the CNC reinforced cellulosic hydrogel‐composites were transparent over all CNC loadings, whereas those reinforced with organoclay were opaque even at low clay loadings despite the nanoparticles being well dispersed. Incorporation of CNC into the cellulosic hydrogels led to an increase in the compressive modulus of CNC‐hydrogel composites, but a corresponding decrease in the swelling ratio. However, the addition of CNCs enabled a reduction in the amount of cross‐linker required to obtain a given compressive modulus and swelling behavior. It was observed that the surface charge density of the CNCs had no significant effect on the compression modulus or swelling behavior of the CMC/HEC hydrogel composites. By contrast, the organoclay reinforced CMC/HEC hydrogels did not show any trend in compression modulus or swelling ratio with organoclay content. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Tracing a major Roman road in the area of ancient Helike by resistivity tomography
Authors: Tsokas G. N. , Tsourlos P. I. , Stampolidis A. , Katsonopoulou D. , Soter S. 
Published: June 2009

AbstractIn his journey through Achaea in the second century AD, Pausanias mentioned the destroyed Classical site of Helike on the sea and noted that its ruins were still visible underwater near the southwest shore of the Corinthian Gulf. In 2001, the Helike Project excavators discovered on the coastal plain of Helike southeast of Aigion the first ruins of Classical buildings, buried under lagoon sediments 3 m deep. They also found segments of a major Roman road oriented NW–SE and buried 1–1.50 m deep under the contemporary surface. Pausanias referred to the main road through the Helike plain, which he followed during his visit. According to his description, he saw the submerged ruins of Helike toward the sea north of the Roman road. Tracing the exact location of the road would, therefore, help to locate the lost city. We employed resistivity tomography to explore the areas between trenches where the road had been unearthed and also to investigate its possible extension beyond those locations. Since 2004, resistivity studies performed by grids or single profiles have been carried out at 11 locations. As a result, the ancient road was detected for a length of about 2 km. It was also imaged either in two‐dimensional or three‐dimensional contexts at all the locations where it was detected. Copyright © 2009 John Wiley & Sons, Ltd.
From the air to beneath the soil – revealing and mapping great war trenches at Ploegsteert (Comines‐Warneton), Belgium
Authors: Masters P. , Stichelbaut B. 
Published: June 2009

AbstractRecent military battlefield sites are often recorded by accident during geophysical investigations researching into earlier archaeological landscapes. The First World War (Great War) perhaps left its traces like no other war before or since in Europe. For the first time, a large area, some 16 ha in extent, has been surveyed over a modern conflict landscape. The authors have attempted to combine two remote sensing techniques: analysis of contemporary Great War aerial photographs and geophysical prospection techniques. The combination of two different approaches leads to a more comprehensive understanding of the Great War battlefield and an understanding of the value of remote sensing in this new area of applied research. Copyright © 2009 John Wiley & Sons, Ltd.
Expression and regulation of the bile acid transporter, OSTα‐OSTβ in rat and human intestine and liver
Authors: Khan Ansar A. , Chow Edwin C. Y. , Porte Robert J. , Pang K. Sandy , Groothuis Geny M. M. 
Published: June 2009

AbstractThe regulation of the OSTα and OSTβ expression was studied in the rat jejunum, ileum, colon and liver and in human ileum and liver by ligands for the farnesoid X receptor (FXR), pregnane X receptor (PXR), vitamin D receptor (VDR) and glucocorticoid receptor (GR) using precision cut tissue slices. The gradient of protein and mRNA expression in segments of the intestine for rOSTα and rOSTβ paralleled that of rASBT. OSTα and OSTβ mRNA expression, quantified by qRT‐PCR, in rat jejunum, ileum, colon and liver, and in human ileum and liver was positively regulated by FXR and GR ligands. In contrast, the VDR ligand, 1,25(OH)2D3 decreased the expression of rOSTα‐rOSTβ in rat intestine, but had no effect on human ileum, and rat and human liver slices. Lithocholic acid (LCA) decreased the expression of rOSTα and rOSTβ in rat ileum but induced OSTα‐OSTβ expression in rat liver slices, and human ileum and liver slices. The PXR ligand, pregnenolone‐16α carbonitrile (PCN) had no effect. This study suggest that, apart from FXR ligands, the OSTα and OSTβ genes are also regulated by VDR and GR ligands and not by PXR ligands. This study show that VDR ligands exerted different effects on OSTα‐OSTβ in the rat and human intestine and liver compared with other nuclear receptors, FXR, PXR, and GR, pointing to species‐ and organ‐specific differences in the regulation of OSTα‐OSTβ genes. Copyright © 2009 John Wiley & Sons, Ltd.
Transport characteristics of candesartan in human intestinal Caco‐2 cell line
Authors: Zhou Lingjie , Chen Xiaoping , Gu Yuanqing , Liang Jianying 
Published: June 2009

AbstractThe intestinal absorptive characteristics and the efflux mechanisms of candesartan (CDS), a novel angiotensin II type 1 receptor blocker, were investigated. The Caco‐2 cells were used as models of the intestinal mucosa to assess uptake and transport of CDS. The determination of CDS was performed by HPLC‐Flu. In the Caco‐2 cells, the uptake and absorptive transport of CDS were pH‐independent (in the pH range 6.0–8.0). Passive membrane diffusion dominates the absorptive transport behavior of CDS across Caco‐2 cells, while secretory transport was a concentration‐dependent and saturable process. In the presence of cyclosporin A and verapamil, potent inhibitors of P‐glycoprotein (P‐gp), the Pratio decreased from 3.8 to 2.3 and 1.8, respectively, and permeation of apical to basolateral was enhanced. Overall, the current study suggests that efflux transporters are capable of mediating the absorption and secretion of CDS, and they may play significant roles in limiting the oral absorption of CDS. Copyright © 2009 John Wiley & Sons, Ltd.
The relation between the specific absorption rate and electromagnetic field intensity for heterogeneous exposure conditions at mobile communications frequencies
Authors: Neubauer Georg , Preiner Patrick , Cecil Stefan , Mitrevski Niki , Gonter Johannes , Garn Heinrich 
Published: June 2009

AbstractThe relation between the incident electromagnetic field strength and both the whole‐body and the local specific absorption rate (SAR) was investigated for typical heterogeneous exposure scenarios for frequencies relevant for mobile communication. The results were compared to results from plane wave exposure. Heterogeneous exposure arises from multiple path propagation of the electromagnetic waves to the location of interest. It is shown that plane wave exposure does not represent worst‐case exposure conditions. When the electric field strength arising at plane wave exposure is compared to the electric field strength averaged over the volume of the human body occurring during multipath exposure, 12% of all heterogeneous cases examined represent worse exposure conditions than plane wave exposure for whole‐body exposure at 946 MHz, 15% at 1840 MHz, and 22% at 2140 MHz. The deviation between plane wave and heterogeneous whole‐body SAR ranges from −54% to 54%. For partial‐body SAR averaged over 10 g of tissue, a range from −93% to 209% was found when comparing multiple wave exposure to single incoming plane waves. The investigations performed using the Visible Human as phantom showed that the basic restrictions are met as long as the reference levels are not exceeded. However, this must not be necessarily the case when different phantoms are used to perform similar investigations because recent studies demonstrated that reference levels might not be conservative when phantoms of children are used. Therefore, the results of this work indicate the need to extend the investigations to numerical simulations with additional human phantoms representing parts of the human population having different anatomy and morphology compared to the phantom used within the frame of this project. This also applies to phantoms of children. Bioelectromagnetics 30:651–662, 2009. © 2009 Wiley‐Liss, Inc.
Zum Querkraftwiderstand bei Leichtbetonbalken ohne Querkraftbewehrung
Authors: Basche Holger D. , Keller Christina 
Published: June 2009

AbstractIn diesem Beitrag wird über Biegeschubversuche mit Leichtbetonbalken ohne Querkraftbewehrung berichtet, die ein ausgeprägtes Nachbruchverhalten aufwiesen. Die Versuchsergebnisse der Leichtbetonbalken werfen die Frage auf, ob die Querkraftbemessung in der neuen DIN 1045‐1 in der Lage ist, hoch spröde Betone wie ALWAC (All Lightweight Aggregate Concrete) hinreichend sicher zu erfassen. In diesem Zusammenhang wird näher auf den Maßstabseffekt eingegangen.Es wurde ein Modell für das Tragverhalten von Biegeschubbalken nach Auftreten des Biegeschubrisses entwickelt, das auf der Kinematik von miteinander verbundenen Festkörpern anstelle von Fachwerkstäben beruht. Ein Ansatz der Tragkapazität im Nachbruchbereich für die Praxis wird nicht empfohlen.Shear Strength of Lightweight Concrete without Shear ReinforcementThis paper presents results of shear beam tests with lightweight concrete and without shear reinforcement exhibiting a distinct post peak behavior. The shear test results raise the question whether the shear design in DIN 1045‐1 can also cover very brittle concrete types as ALWAC (All Lightweight Aggregate Concrete) with a sufficient safety level. The size effect in shear beams is discussed.A model for the load bearing behavior after formation of the inclined crack based on the kinematics of a set of rigid bodies is developed. A consideration of the additional load capacity in the post peak range in design formulas is not recommended.
Versuche zur Ermüdungsfestigkeit alter Betonstähle
Authors: Fehlmann Patrick , Vogel Thomas 
Published: June 2009

AbstractDie Frage der Ermüdungssicherheit hat im Zusammenhang mit der Überprüfung bestehender Stahlbetonbauwerke, insbesondere Brücken, an Aktualität gewonnen. Während auf der Einwirkungsseite die Anzahl der Lastwechsel und die Lasten, die die Brücke im Laufe ihres Lebens erfahren hat, von Bedeutung sind, sind es auf der Widerstandsseite die Genauigkeit des Tragwerkmodells und die Materialkennwerte. Mit Letzteren befasst sich dieser Aufsatz. Der wichtigste Parameter auf der Widerstandsseite ist die Ermüdungsfestigkeit des Betonstahls. Mittels Dauerschwingversuchen wurde die Ermüdungsfestigkeit von vier Betonstahlsorten ermittelt. Zwei Sorten stammen von abgebrochenen Brücken aus den 1950er Jahren; zwei weitere sind kürzlich produzierte Sorten von Ring‐ und Stabmaterial der Betonstahlsorte B 500 B. Das Ziel der Versuche bestand darin, festzustellen, ob das Alter einer Stahlbetonkonstruktion einen Einfluss auf die Ermüdungsfestigkeit des Betonstahls hat. Im Aufsatz werden die Problematik beim Nachweis der Ermüdungssicherheit bestehender Brücken kurz geschildert, die Versuche beschrieben und deren Resultate diskutiert.Fatigue Tests with Old Reinforcing SteelsRecently, fatigue safety has become an issue with respect to surveying the condition of existing structures, in particular bridges. While questions considering traffic loads and frequencies dominate the calculations of the appropriate load scenarios, the accuracy of the structural model and material properties play a vital role for the calculation of the resistance. This article deals with the latter. The most important parameter on the resistance side is the fatigue strength of the reinforcement. Therefore, fatigue strength of four brands of reinforcing steel was determined in fatigue tests. Two brands of reinforcement bars could be gathered during demolition work of two bridges which were built in the 1950ies. Another two brands of new reinforcing steel B 500 B, a rod‐steel and a steel from the roll, were tested. The aim of the tests was to prove whether age and environment of the built‐in reinforcement bars affect their fatigue resistance or not. The article briefly describes the difficulties with verifying the fatigue safety of existing bridges while the main part deals with the experimental work and the discussion of the test results.