bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solid state properties of thin films of new copoly(azomethine‐sulfone)s
Authors: Marin Luminita , Timpu Daniel , Cozan Vasile , Rusu Gheorghe I. , Airinei Anton 
Published: December 2010

AbstractA series of four copoly(azomethine‐sulfone)s have been synthesized and extensively characterized. The chemical design has been thought to obtain semiconducting properties and thermotropic behavior matching the processing of the materials from the ordered melted state, suitable for the spontaneous alignment of molecules in the active layer on a substrate. Prototypes of thin films based on this series of polymers have been electrically and structurally characterized. It was found that the respective polymers show typical semiconducting properties. The thermal properties with particular reference to their mesomorphic state were checked by using differential scanning calorimetry, polarized light microscopy, and thermogravimetric analysis techniques. Morphological characterization was realized by atomic force microscopy and X‐ray diffraction measurements. Some correlations between electrical properties and packing closeness were established. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Mechanical properties of reinforced polyvinyl chloride composites: Effect of filler form and content
Authors: Ashori Alireza , Kiani Hojatollah , Mozaffari S. Ahmad 
Published: December 2010

AbstractIn this study, to understand how cellulosic materials characteristics influence the mechanical properties of polyvinyl chloride (PVC) composites, we first studied the effect of different types (wood flour and pulp fiber) and contents on selected mechanical properties of uncompatibilized wood plastic composites. We then compared the properties of hybrid composites to those of composites reinforced with wood flour or fiber, individually. PVC as polymer matrix and cellulosic materials were compounded by twin‐screw extrusion and test specimens were prepared by injection molding. All tested properties vary significantly with filler form or content. With the addition of wood flour, the tensile strength moderately increases, but with the addition of hybrid filler and pulp fiber, it increases significantly. Notched impact strength increased with increasing particle size. Pulp fiber resulted in higher strength at the 40 wt % level compared with the strength properties of wood flour composites. The higher aspect ratio of the fiber had significant effect on the mechanical properties. Increasing filler load improves the strength of the composite up to a load of 40 wt %, further increase in the filler loading (>40 wt %) results in a decrease in properties, due to the to filler agglomerates. Incorporation of 25% weight fraction of wood pulp fiber in hybrid composites gave the highest values of composite properties. The mechanical properties of hybrid composites are found to be much higher than that composites filled with wood flour. Finally, results showed that the hybrid composites had the maximum improvement in selected mechanical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Thermal properties of epoxidized natural rubber‐based polymer blends
Authors: Chan C. H. , Sulaiman S. F. , Kammer H. W. , Sim L. H. , Harun M. K. 
Published: December 2010

AbstractThermal properties and morphologies of different thermoplastic polymers blended with an elastomer are discussed. Poly(ethylene terephthalate) (PET), poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) with 12%mole of hydroxyvalerate content (PHBV) and poly(ethylene oxide) (PEO) were blended with epoxidized natural rubber (ENR). These blends turn out to be immiscible. Degree of crystallinity after isothermal crystallization and equilibrium melting point of the crystallizable constituents stay constant to a good approximation in blends with ENR. Exponential decay of rate of crystallization could be observed for both neat polymers and blends. Morphology formation was observed under condition of constant rate of crystallization, which is concomitantly related to different distances to equilibrium. It turns out that morphology development in the blends reflects both aspects. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Nanostructures generated from photopolymerization of poly(ethylene glycol) diacrylate templated from hexagonal lyotropic liquid crystals
Authors: Zhang Juan , Xie Zongli , Hua She Feng , Hoang Manh , Hill Anita J. , Min Gao Wei , Kong Ling Xue 
Published: December 2010

AbstractThe use of lyotropic liquid crystals (LLC) as a template to form periodic nanostructures in polymer materials is a promising technology. In this study, cross‐linked poly(ethylene glycol) diacrylate nanostructured materials were prepared by photopolymerization in LLC hexagonal phases. Polarized light microscopy and small‐angle powder X‐ray diffraction were used to understand the original LLC order retention on photopolymerization, and scanning electron microscope was used to investigate the morphology under different purifying solvents and drying conditions. A Quantachrome Autosorb 1 system was used to study the pore size distribution of samples. It was found that the LLC hexagonal structure was retained to a great extent after photopolymerization. The formation of nanostructures was affected by purifying solvent and drying condition. The nanostructure synthesized from LLC with favorably aligned nanopores will find increasing applications in gas and water filtration, biology, and health science. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Ion‐imprinted PHEMA based monolith for the removal of Fe3+ ions from aqueous solutions
Authors: Özkara Serpil , Andaç Müge , Karakoç Veyis , Say Rıdvan , Denizli Adil 
Published: December 2010

AbstractMolecular recognition based Fe3+ imprinted monolith was prepared for selective removal of Fe3+ ions from aqueous solutions. The precomplexation was achieved by the coordination of Fe3+ ions with N‐methacryloyl‐(L)‐cysteine methyl ester (MAC) to form the complex monomer (MAC‐Fe3+). The polymerization step was then carried out in the presence of MAC‐Fe3+ complex and hydroxyethyl methacrylate (HEMA) monomer by bulk polymerization to constitude a Fe3+‐imprinted polymer (PHEMAC‐Fe3+). The specific surface area of PHEMAC‐Fe3+ monolith was found to be 35.2 m2/g, with a swelling ratio of 60.2% after the template was removed from the monolith by 0.1M EDTA solution. The maximum adsorption capacity of PHEMAC‐Fe3+ monolith for Fe3+ ion was 0.76 mg/g. The adsorption behavior of the monolith has been successfully described by the Langmuir isotherm. It was determined that the relative selectivity of PHEMAC‐Fe3+ monolith was 59.7 and 37.0 times greater than that of the nonimprinted PHEMAC monolith as compared with the Cd2+ and Ni2+ ions, respectively. The PHEMAC‐Fe3+ monolith was recovered and reused many times without any significant decrease in its adsorption capacity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Mechanical performance of hybrid rice straw/sea weed polypropylene composites
Authors: Hassan M. Masudul , Mueller Marco , Tartakowska Diana J. , Wagner Manfred H. 
Published: December 2010

AbstractRice straw (Rs)/polypropylene (PP) composites were prepared in the different ratio of 5 : 95, 10 : 90, 15 : 85, 20 : 80, 25 : 75, and 30 : 70 (Rs wt % : PP wt %) by an injection molding process. This work investigated the tensile strength (TS), bending strength (BS), and impact strength (IS) of the composites. From the results, it is observed that Rs20 : PP80 mixture composite showed better performance with mechanical properties (TS = 26.2 MPa, BS = 58 N/mm2, and IS = 1.7 KJ/mm2) among the composites prepared. Two hybrid composites were also fabricated using 20% Rs, 10% seaweed with 70% PP and 20% Rs, 30% seaweed with 70% PP. In between the two hybrid composites, superior mechanical behavior showed by the hybrid composite in ratio of Rs20 : Sw10 : PP70 with enhanced results such as TS = 28 MPa, BS = 68 N/mm2, and IS = 2.5 KJ/mm2. Water uptake, simulating weathering, and soil degradation test of different composites were also performed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Influence of flexible oligo(tetrafluoroethene) segment on the sorption and diffusion of carbon dioxide in poly(amide‐imide) membranes
Authors: Chen Yu , Huang Shu Ping , Liu Qing Lin , Broadwell Ian , Zhu Ai Mei 
Published: December 2010

AbstractMolecular simulations have been used to study the sorption and diffusion properties of carbon dioxide in a series of poly (amide‐imide) (PAI) membranes containing oligo(tetrafluoroethene) segment with various numbers (n = 0, 1, 2, 3, and 4) of tetrafluoroethene units. The solubility and self‐diffusion coefficients were computed by the Grand Canonical Monte Carlo (GCMC) method and molecular dynamics (MD) simulations respectively. It was found that increasing the fluorine content of the polymer membrane reduced the associated glass transition temperature (Tg) and led to an increase in diffusion coefficient of carbon dioxide. Results indicate that penetrant molecule's diffusion coefficient is strongly dependent on chain mobility. It is also noticed that the radial distribution functions (RDFs) are inconsistent with the d‐spacings of PAIs calculated form X‐ray data. This is also thought to be tied to the number of degrees of freedom of the chain. Finally, this study gives a useful insight into how PAIs with high fluorine content can be tailored with a high permeability to carbon dioxide. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Familiarity with Latin and Greek anatomical terms and course performance in undergraduates
Authors: Pampush James D. , Petto Andrew J. 
Published: December 2010

AbstractCommonly used technical anatomy and physiology (A&P) terms are predominantly rooted in Latin and Greek vocabulary, so it is commonly inferred that a solid grounding in Latin and Greek roots of medical terminology will improve student learning in anatomy and related disciplines. This study examines the association of etymological knowledge of A&P terms and A&P course performance among 446 undergraduates in their first semester of the study of human gross anatomy and physiology, with a more detailed analysis of the characteristics of 52 students who filled out surveys about their prior knowledge and experiences related to medicine or anatomy. In both data sets, there was only a weak positive correlation between the performance on a quiz of Latin and Greek medical terms and the students' performance on regular assignments. The presumption that familiarity with Latin and Greek word roots has a strong influence on successful learning of anatomy is not supported by these data. Future research should address whether or not there are particular skills associated with using etymological knowledge in improving A&P course performance. Anat Sci Educ. © 2010 American Association of Anatomists.
Adaptive rejection of disturbances having two sinusoidal components with close and unknown frequencies
Authors: Guo Xiuyan , Bodson Marc 
Published: December 2010

AbstractThe paper considers the problem of rejecting disturbances with two sinusoidal components in the case where the frequencies are unknown and closely spaced. A natural approach consists of cancelling the components using two separate adaptive algorithms combined in a single scheme. However, experiments in active noise control applications have shown that convergence using such an approach could be very slow. The alternative approach of this paper consists of representing the disturbance signal as a single sinusoid with time‐varying magnitude and phase. The theoretical basis and the limitations of this representation are first discussed. Then, an adaptive disturbance rejection algorithm is proposed and the resulting nonlinear system is analyzed using some approximations. Active noise control experiments demonstrate that the proposed algorithm has better convergence properties than an algorithm designed to cancel the two frequency components separately. In some cases, however, the cost is a small residual error on the output signal.Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Oscillating Bromate Oxidative Reactions
Authors: Zhabotinsky A. M. 
Published: December 2010

AbstractIn this contribution a survey of the recent data on oscillating bromate oxidative reactions is given. The main part of the paper deals with the reaction mechanism. The simplest hypothesis on the mechanism of these reactions can be outlined: all the dynamic features of the system are defined by the kinetics of the reaction (1)magnified imageprovides only a linear feedback.
Action Potentials in Lipid Bilayers
Authors: Müller Paul 
Published: December 2010

AbstractThe construction of a molecular mechanism capable of generating action potentials in lipid bilayers is described. — A protein called EIM obtained from enterobacter cloacae, forms cation selective channels which can be opened and closed by the membrane potential. In sphingomyelin‐tocopherol membranes the membrane conductance changes over 3 — 4 orders of magnitude between —60 and + 25 mV. In an ionic concentration gradient the membranes generate a cationic resting potential of up to 70 mV. This potential acts as an applied potential and closes most of the channels. When protamine is added to a membrane containing EIM, the channels become anion selective
What Can we Learn about Dissipative Structures by Model Reactions
Authors: Schlögl F. 
Published: December 2010

AbstractSome questions will be listed which could be answered by the use of simple reaction models, developed in recent years and showing typical phenomena of nonlinear thermodynamics like chemical instabilities, bifurcations, and nonequilibrium phase transitions. A comparison will be made of different forms of descriptions. These are a deterministic theory and stochastic theories based on the use of Langevin forces or of a master equation. The role of certain general stochastic measures as thermodynamic quantities will be discussed. An outlook on possible extensions to limit cycle models will be given.
Periodische Bildung von cycli‐AMP‐Signalen und Chemotaxis von Dictyostelium‐Zellen
Authors: Gerisch GüNther 
Published: December 2010

AbstractExperimental data on oscillations in aggregating cells of the microorganism Dictyostelium discoideum have recently been reviewed by Gerisch et al. (1979). A mathematical analysis based on these data has been published by Sperb (1979).In summary, cells of Dictyostelium discoideum are able to release cyclic AMP periodically and to respond to the same factor by chemotactic orientation. The oscillations of cAMP generation are based on activity changes of adenylate cyclase. Cyclic AMP receptors on the cell surface are functionally coupled to the oscillating system as evidenced by phase shifts that were induced by small pulses of extracellular cAMP. As an important element of the oscillating system the signal processing from cell surface receptors to the adenylate cyclase has been investigated. This pathway exhibits adaptation resulting in the suppression of responses to constant, elevated concentrations of cAMP. The adequate signal input for adenylate cyclase activation is therefore a change of the extracellular cAMP concentration with time.Oscillations in the absence of detectable changes of intra‐ or extracellular cAMP concentrations raise the question if there is a network in D. discoideum cells that undergoes oscillations without being coupled to adenylate cyclase. Cyclic GMP concentrations oscillate with a slight phase difference in advance of c‐AMP, suggesting that the two nucleotide cyclases are independently activated. Rise of extracellular calcium concentrations exert an inhibitory effect on the intracellular accumulation of both cGMP and cAMP.
Thermokinetic Oscillations in Propane Oxidation
Authors: Lignola P. G. , Caprio V. , Insola A. , Mondini G. 
Published: December 2010

AbstractA continuous stirred tank reactor (CSTR) has been adopted for the gas phase oxidation of hydrocarbons. This experimental technique permits the existence of oscillatory phenomena to be revealed. Hard excitations, periodic ignitions, purely periodic and damped cool flames, and complex oscillatory events can be observed. In this work the parametric dependence on temperature and residence time of the observed behaviour is established for the system propane‐oxygen. Regions of existence of each phenomenon are thus defined in the residence time‐
Models of Chemical Reaction Systems with Exactly Evaluable Limit Cycle Oscillations and their Bifurcation Behaviour
Authors: Escher C. 
Published: December 2010

AbstractModels of open chemical reaction systems with two variables x,y and with elliptic limit cycles in concentration space are investigated. Thereby isothermal and homogeneous conditions and the validity of mass‐action kinetics are assumed. Though we restrict ourselves to quadratic rate equations a lot of systems with this behaviour is found; all based on the trimolecular reaction A + 2X → 3X. Both globally stable and only locally stable limit cycles are possible. The time dependence of the variables on the cycle is exactly evaluated for all these systems. By means of simple examples both Hopf bifurcation and other types of transition of the limit cycle are studied analytically. Finally the qualitatively different properties of these transitions are pointed out in a table.
Spatial Dissipative Structures in Yeast Extracts
Authors: Boiteux Arnold , Hess Benno 
Published: December 2010

AbstractBy means of high resolving UV‐photographic techniques the conditions for the occurrance of dynamic spatial structures in glycolyzing yeast extracts are reported. The methods allow to record the phenomena of excitability, signal transmission, propagation and interference of waves, as well as the development and transformation of spatial temporal patterns. The glycolyzing yeast extract is the first biochemical system in homogeneous phase which has been shown to exhibit not only temporal but also spatial structures. Our results are discussed in terms of the theory of dissipative space structures.
Ansatz zur Beurteilung von chloridbelasteten Stahlbetonbauwerken mit Bewertung der Restlebensdauer
Authors: Wendner Roman , Strauss Alfred , Guggenberger Theodor , Bergmeister Konrad , Teplý Bretislav 
Published: December 2010

AbstractDie Sicherstellung eines ausreichenden Zuverlässigkeitsniveaus im Rahmen der Erhaltung von Bauwerken und insbesondere Betonbrücken, welche durch Verkehrs‐ und Umwelteinflüsse einer kontinuierlichen Verschlechterung im Laufe ihrer Lebenszeit unterliegen, ist in der Regel eine komplexe und teure Aufgabenstellung. Besonders in Regionen mit Streusalzeinsatz in der Winterzeit beeinflusst die Chloridbelastung sowohl den Entwurf als auch die Erhaltung der Bauwerke durch ihren Einfluss auf die Dauerhaftigkeit wesentlich. In diesem Beitrag wird eine Bewertungsstrategie für die durch die Chloridbelastung hervorgerufene Zustandsverschlechterung von Betonstrukturen und deren Auswirkung auf das Sicherheitsniveau sowie die verbliebene Lebenszeit an einem Fallbeispiel vorgestellt. Hierbei werden die Entnahme von Proben, deren Untersuchung, die inverse Analyse des Eindringverhaltens und infolge die Prognose der Chloridkonzentration im Bauteil, die Vorhersage der Korrosionsentwicklung über die Zeit und schließlich die Bestimmung des gegenwärtigen und zukünftigen Zuverlässigkeitsniveaus unter Beachtung der normativ festgelegten Grenzzustände für Tragfähigkeit und Gebrauchstauglichkeit behandelt. Schlussendlich werden unterschiedliche Erhaltungsstrategien in Bezug auf die zu erwartenden Lebenszykluskosten verglichen.Approach for the Assessment of Concrete Structures Subjected to Chloride Induced DeteriorationThe maintenance of an adequate safety level of concrete bridges under their gradual degradation due to traffic and environmental actions during service life is an expensive, problematic and questionable task. Chloride ion ingress is an important aspect of durability design and maintenance, especially in regions where winter salt application for traffic safety is common, e. g. for highways. A feasible approach for the assessment of chloride induced deterioration and its consequences on the safety level, remaining service life and thus maintenance planning will be presented by a case study. Steps include the extraction of samples, laboratory test, inverse analysis and prognosis of chloride ingress, prediction of likely corrosion propagation over time and determination of the current and future safety level with regard to code based service limit states and ultimate limit states. Finally different maintenance strategies are compared with respect to the total life cycle costs.
Evaluation on factors influencing the heterotrophic growth on the soluble microbial products of autotrophs
Authors: Ni Bing‐Jie , Zeng Raymond J. , Fang Fang , Xie Wen‐Ming , Xu Juan , Sheng Guo‐Ping , Sun Yu‐Jiao , Yu Han‐Qing 
Published: December 2010

AbstractIn this work, the heterotrophic growth on the microbial products of autotrophs and the effecting factors were evaluated with both experimental and modeling approaches. Fluorescence in situ hybridization (FISH) analysis illustrated that ammonia oxidizers (AOB), nitrite oxidizers (NOB), and heterotrophs accounted for about 65%, 20%, and 15% of the total bacteria, respectively. The mathematical evaluation of experimental data reported in literature indicated that heterotrophic growth in nitrifying biofilm (30–50%) and granules (30%) was significantly higher than that of nitrifying sludge (15%). It was found that low influent ammonium resulted in a lower availability of soluble microbial products (SMP) and a slower heterotrophic growth, but high ammonium (>150 mg N L−1) feeding would lead to purely AOB dominated sludge with high biomass‐associated products contained effluent, although the absolute heterotrophic growth increased. Meanwhile, the total active biomass concentration increased gradually with the increasing solids retention time, whereas the factions of active AOB, NOB, and heterotrophs varied a lot at different solids retention times. This work could be useful for better understanding of the autotrophic wastewater treatment systems. Biotechnol. Bioeng. 2011; 108:804–812. © 2010 Wiley Periodicals, Inc.