bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of polymer fiber stationary phases for liquid chromatography separations: Part I – physical and chemical rationale
Authors: Marcus R. Kenneth 
Published: July 2008

AbstractThe idea of using polymer fibers as stationary phases for LC is not a new one. There are in fact a number of good reasons for which they should be considered. To this point though, they have not produced sufficiently good performance to garner much commercial interest. Presented here are the physical and chemical rationale by which they should show enhanced performance relative to conventional stationary phases. Most notably, the mass transport and hydrodynamic characteristics suggest applications in areas of macromolecule and prep‐scale separations. Additionally, there exists an incredible wealth of polymer surface chemistries and potential derivatization pathways that greatly exceed what is practical on conventional silica supports. The potential for important impact suggests further research into polymer fiber phases.
Evaluation of protein, peptide, and amino acid retention on C5 hydride‐based stationary phases
Authors: Pesek Joseph J. , Matyska Maria T. , Venkat Jayasree Pindi 
Published: July 2008

AbstractA pentyl (C5) stationary phase is synthesized on a hydride surface using both 100 and 300 Å silica particles. The aqueous normal phase properties of these new phases are evaluated using amino acids at high concentrations of ACN in the mobile phase containing 0.1% formic acid. The RP properties of the materials are tested by using peptides and proteins in order to evaluate the effect of pore size on retention. Comparisons of retention as well as efficiencies and peak symmetry with a C18 phase are used to determine the influence of the hydrophobic properties of the bonded material. An evaporative light scattering detector (ELSD) is used in all phases of the study and compared with UV detector for gradient elution of proteins.
Considerations on HILIC and polar organic solvent‐based separations: Use of cyclodextrin and macrocyclic glycopetide stationary phases
Authors: Wang Chunlei , Jiang Chunxia , Armstrong Daniel W. 
Published: July 2008

AbstractThere is a natural tendency in science to prefer straightforward, logical classification systems. The use of mobile phase–stationary phase combinations that do not fit neatly into the standard “normal phase” or “reversed‐phase” categories has been going on for over 50 years. The term “hydrophilic interaction chromatography” (HILIC) is sometimes being used as a general category for these “other” separations. In some cases, it may be appropriate and in others, not. Indeed the mechanistic constrains used to define the method seem to be varying with time. Given the name HILIC, it is assumed that water is not only present in the mobile phase, but also plays an essential role in the retention mechanism. However, there is residual water present in all organic solvents. Regardless, the number of reported separations in this alternative mode has increased tremendously in the last two decades. This is due to the advent of new stationary phases and an emphasis on polar, biologically important molecules. We discuss the relationships between HILIC and other chromatographic modes. We then examine two classes of stationary phases that have played a major role in these separations. These particular stationary phases can be used to provide appreciable mechanistic information as well.
Determination of volatile and non‐volatile products of milk fermentation processes using capillary zone electrophoresis and solid phase microextraction coupled to gas chromatography
Authors: Ligor Magdalena , Jarmalaviciene Reda , Szumski Michal , Maruška Audrius , Buszewski Boguslaw 
Published: July 2008

AbstractThe aim of the investigations was to develop analytical methods for the determination of selected volatile and non‐volatile organic compounds numbering among the final products of milk fermentation. The analyzed compounds were as follows: biacetyl and carboxylic acids (formic, acetic, citric, and lactic). The model yogurt was prepared under controlled conditions in our laboratory by addition of the selected bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus) to the milk sample. The temperature, time, and stirring were controlled during the fermentation process. Factors considered in SPMPE–GC–FID method development included fiber exposure time, salt addition, temperature of extraction, and temperature of desorption. Various SPME fibers, for example with PDMS, CAR/PDMS, PA, and PDMS/DVB coatings, were tested to obtain the highest recovery of the investigated compounds extracted from yogurt samples. Based on these preliminary experiments, qualitative and quantitative analyses for the determination of biacetyl were performed by SPME–GC–FID. Moreover, a capillary zone electrophoresis method was developed for the determination of carboxylic acids in the yogurt samples. The buffer composition as well as deproteinization by acetonitrile were found to have a crucial effect on the analysis.
Separation of inorganic anions on a high capacity porous polymeric monolithic column and application to direct determination of anions in seawater
Authors: Evenhuis Christopher J. , Buchberger Wolfgang , Hilder Emily F. , Flook Kelly J. , Pohl Christopher A. , Nesterenko Pavel N. , Haddad Paul R. 
Published: July 2008

AbstractA commercially available 4.6 mm id×50 mm polymethacrylate‐based monolithic strong anion exchange column (ProSwiftTM SAX‐1S) designed for the separation of proteins has been successfully used to separate small inorganic anions in the presence of a seawater sample matrix. Using a hydroxide eluent with suppressed conductivity detection the ion exchange capacity of this column declined over time; however, using KCl as the eluent, the column performance was stable with a capacity of 530 μequiv. for nitrate. The optimum conditions for the separation of iodate, bromate, nitrite, bromide and nitrate were assessed by constructing van Deemter plots using 1.00 and 0.100 M KCl. Efficiencies of up to 26 700 plates/m were recorded using 1.00 M KCl, at a flow rate of 0.20 mL/min but iodate was not baseline resolved from the void peak. By reducing the concentration of the eluent to 0.100 M, efficiencies of up to 39 900 plates/m could be obtained at 0.35 mL/min. By employing a linear gradient ranging from 0.05 to 1.00 M KCl the ions dissolved in distilled water or a salt water matrix could be baseline separated in less than 3 min at a flow rate of 2.50 mL/min.
Holiday users of the Internet — ease of use, functionality and novelty
Authors: Ryan Chris , Rao Ulhas 
Published: July 2008

AbstractThis study is based upon a sample of 517 international visitors to New Zealand. It suggests that Internet usage is based upon perceived usefulness and ease of system use. Of additional importance is user confidence about system security. Functional issues of purchasing seem to take priority over information search as users become more familiar with web pages. An additional finding is that entertainment needs are arguably better met by other Internet functions than those provided by destination web pages. Novelty on the Net is perhaps sought from specific sources, and not from the Net generally. Implications are discussed for both measurement and marketing. Copyright © 2008 John Wiley & Sons, Ltd.
Carbon stocks in Ethiopian soils in relation to land use and soil management
Authors: Girmay G. , Singh B. R. , Mitiku H. , Borresen T. , Lal R. 
Published: July 2008

AbstractThe effect of soil management and land use change are of interest to the sustainable land management for improving the environment and advancing food security in developing countries. Both anthropogenic changes and natural processes affect agriculture primarily by altering soil quality. This paper reviews and synthesizes the available literatures related to the influence of soil management and land use changes on soil carbon (C) stock in Ethiopia. The review shows that topsoil C stock declines approximately 0–63%, 0–23%, and 17–83% upon land use conversion from forest to crop land, to open grazing, and to plantation, respectively. An increase of 1–3% in soil C stock was observed within 10 years of converting open grazed land to protected enclosures. However, there was a little change in soil C stock below 20 cm depth.There is a large potential of increasing SOC pool with adoption of land restorative measures. Total potential of soil C sequestration with the adoption of restoration measures ranges 0·066–2·2 Tg C y−1 on rain‐fed cropland and 4·2–10·5 Tg C y−1 on rangeland. Given large area and diverse ecological conditions in Ethiopia, research data available in published literature are rather scanty. Therefore, researchable priorities identified in this review are important. Copyright © 2008 John Wiley & Sons, Ltd.
Biomaterials and Biofunctionality in Layered Macromolecular Assemblies
Authors: Ariga Katsuhiko , Hill Jonathan P. , Ji Qingmin 
Published: July 2008

AbstractRecent research in the field of LbL assembly is summarized and categorized as fabrication, sensing, drug release/delivery, and cell technology. Special emphasis is given to topics such as cell‐membrane‐mimic assembly, fabrication of free‐standing biomolecular structures including protein microtubes, detection of DNA adducts and reactive metabolites, DNA hybridization analysis, sensing of toxic and bio‐active chemicals, entrapment of proteins and DNA, biocomponent carriers with barcode encoding, release and delivery of DNA plasmids, multiagent delivery, smart defense capsules and oxidation‐resistant films, vector introduction to cells, patterned cell culturing and microfluidic microreactors, stem cell differentiation, cellular uptake and degradation, and control of cellular apoptosis.magnified image
A software tool for lifetime prediction of thermal barrier coating systems
Authors: Busso E. P. , Evans H. E. , Wright L. , McCartney L. N. , Nunn J. , Osgerby S. 
Published: July 2008

AbstractThermal barrier coatings (TBCs) are widely used to extend the lifetime of key components within gas turbines, and so the ability to predict the lifetime of TBCs is a high priority for gas turbine users. A complete model of TBC failure requires characterisation of the coating system, identification of the main failure mechanisms, quantitative description of stress evolution in the key areas within the coating system and robust failure criteria for each failure mechanism. Thus lifetime prediction invariably requires a massive effort both in terms of determining the appropriate input parameters for the model and in computing the solution.In order to reduce the need for extensive calculation, a software tool has been developed that interpolates the key stresses for each failure mechanism from a matrix of previously calculated values. The matrix of values is generated using a recently developed finite element (FE) model of TBC lifetime of an IN738/MCrAlY/EB‐PVD YSZ system. The stress distribution predicted by this model is dependent on exposure time and temperature as well as the morphology of the bond coat/ceramic interface and requires FE calculation for each specific set of conditions. The software tool interpolates the FE results with respect to time, temperature and a geometric parameter to predict key stresses that drive failure, and coating system lifetime.This paper describes the principles behind the development of the algorithms implemented in the software tool. Validation of the approach is in progress through comparison of predictions with non‐destructive measurements on the coating system.
Waste incineration corrosion processes: Oxidation mechanisms by electrochemical impedance spectroscopy
Authors: Pérez F. J. , Hierro M. P. , Nieto J. 
Published: July 2008

AbstractMolten chloride mixtures are formed in waste incineration plants during waste firing and energy production. These mixtures are responsible for degradation processes like hot corrosion. In order to evaluate the damage of molten salt mixtures in waste incineration environments, the alloys 625 and 617 were exposed beneath a molten KCl‐ZnCl2 mixture at 650 °C in air. The corrosion process was monitored by electrochemical impedance spectroscopy (EIS). An extensive microscopy analysis has been done in order to correlate the electrochemical results, and to establish an electrochemical mechanism for such high temperature corrosion processes.
Protective coatings for very high temperature reactor applications
Authors: Cabet C. , Thieblemont F. , Guerre C. 
Published: July 2008

AbstractThe future very high temperature reactors (VHTR) are nuclear systems that shall operate at a maximum temperature of about 950 °C. Primary circuit materials thus require good creep and corrosion resistance on very long time. Use of high‐strength alloys with protective coatings could significantly improve the service life of high temperature reactor components. However, coating systems are mainly designed for shorter term purposes, often under extremely aggressive atmospheres, that cannot be extrapolated to the VHTR environment. We present our first investigations on the environmental resistance of Alloy 800H coated with two different protective systems under VHTR representative conditions: NiAl(Pt)/EBPVD ZrO2(Y) and NiCrAl(Y)/CVD ZrO2(Y). Isothermal exposures were carried out up to 1000 h at 950 °C in impure helium. This specific atmosphere was shown to induce formation of a surface oxide scale together with carburisation of the bare Alloy 800H. After high temperature exposure to impure helium, the microstructure of the coated specimens has changed due to both thermal ageing and corrosion. Performances of the two coating systems are compared regarding the VHTR application.
Experimental analysis and computer‐based simulation of nitridation of Ni‐base alloys—the effect of a pre‐oxidation treatment
Authors: Trindade V. B. , Krupp U. , Gorr B. , Kaczorowski D. , Girardin G. , Christ H.‐J. 
Published: July 2008

AbstractNickel‐base superalloys are commonly used for high‐temperature applications in power‐generation industry, e.g., gas‐turbine blades or heat exchangers. They are designed to resist high creep loading and severe corrosion attack during operation. Nitridation is one of these corrosion processes, in particular when the alloys need to be exposed to a N2 atmosphere. Based on past assumptions, a dense oxide layer should be an efficient barrier against N2 ingress. But is this really the case? This work is focused on the nitridation behavior of commercial Ni‐base alloys and the influence of a pre‐oxidation treatment. To model the growth of the internal‐nitridation zone, the diffusion processes were solved using the numerical implicit finite‐difference method in combination with the subroutine ChemApp for thermodynamic calculations.
Influence of alloy compositions on the halogen effect in TiAl alloys
Authors: Masset P. J. , Neve S. , Zschau H.‐E. , Schütze M. 
Published: July 2008

AbstractF‐implantation concentration profile simulations were carried out and the influence of the ion fluence, implantation energy as well as the alloy composition were investigated. For alloys with Al contents between 40 and 50 at% the conditions to get the halogen effect were assessed by thermodynamic calculations. According to the thermodynamic predictions the implantation parameters were kept constant in this composition range. The implanted alloys were exposed in laboratory air over 4000 h. With the implantation parameters used (20 keV and 1 × 1017 F/cm2), the halogen effect was found to be efficient over 4000 h. The oxide growth kinetic constants were measured and vary between 1.2 and 2.7 × 10−13 g2/cm4/s.
High‐temperature oxidation of Ti3Al0.7Si0.3C2 compound at 900 and 1000 °C in air
Authors: Lee D. B. , Nguyen T. D. 
Published: July 2008

AbstractThe compound, Ti3Al0.7Si0.3C2, was synthesized by hot pressing a powder mixture of TiCX (x = 0.6), Al and Si. Its oxidation at 900 and 1000 °C in air for up to 50 h resulted in the formation of rutile‐TiO2, α‐Al2O3 and amorphous SiO2. The oxide scales formed consisted of triple layers, viz, an outer TiO2 layer containing Al2O3 particles, an intermediate Al2O3 layer, and an inner mixed layer that was rich in TiO2, but deficient in Al2O3 and SiO2. During oxidation, Ti diffused outwards to form the outer TiO2 layer, and oxygen was transported inwards to form the inner mixed layer. At the same time, carbon was liberated from Ti3Al0.7Si0.3C2. Ti3Al0.7Si0.3C2 oxidized slower than the TiO2‐forming kinetics, but faster than the (α‐Al2O3 or SiO2)‐forming kinetics.
Poisson's Ratio of Monodomain Liquid Crystalline Elastomers
Authors: Ren Wanting , McMullan Philip J. , Griffin Anselm C. 
Published: July 2008

AbstractMonodomains of smectic C liquid crystalline elastomers were prepared by controlled stretching of a polydomain thin film. Specimens were prepared from this film for stress–strain study. A Poisson's ratio of zero was found at small strains for uniaxial stretching perpendicular to the director. For uniaxial strain parallel to the director, Poisson's ratios of approximately 0.4–0.5 were found (by extrapolation) for very small strains. A modulus anisotropy of 8 was found for stretching parallel versus perpendicular to the director.magnified image
On contraction and the modal fragment
Authors: Brünnler Kai , Probst Dieter , Studer Thomas 
Published: July 2008

AbstractWe observe that removing contraction from a standard sequent calculus for first‐order predicate logic preserves completeness for the modal fragment. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bisimulations between generalized Veltman models and Veltman models
Authors: Vuković Mladen 
Published: July 2008

AbstractInterpretability logic is an extension of provability logic. Veltman models and generalized Veltman models are two semantics for interpretability logic. We consider a connection between Veltman semantics and generalized Veltman semantics. We prove that for a complete image‐finite generalized Veltman modelW there is a Veltman model W ′ that is bisimular to W. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Positive Frege and its Scott‐style semantics
Authors: Libert Thierry 
Published: July 2008

AbstractWe show that the untyped λ ‐calculus can be extended with Frege's interpretation of propositional notions, provided we restrict β ‐conversion to positive expressions. The system of illative λ ‐calculus so obtained admits a natural Scott‐style semantics. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A note on the first‐order logic of complete BL‐chains
Authors: Hájek Petr , Montagna Franco 
Published: July 2008

AbstractIn [10] it is claimed that the set of predicate tautologies of all complete BL‐chains and the set of all standard tautologies (i. e., the set of predicate formulas valid in all standard BL‐algebras) coincide. As noticed in [11], this claim is wrong. In this paper we show that a complete BL‐chain B satisfies all standard BL‐tautologies iff for any transfinite sequence (ai: i ∈ I) of elements of B, the condition ∧i ∈ I (a2i ) = (∧i ∈ I ai)2 holds in B. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A model of adoption of digital multimedia broadcasting (DMB) service: Comparisons in Korea, Japan, and Germany
Authors: Kim Kyung Hoon , Ko Eunju , Takahashi Ikuo , Schellhase Ralf , Kim Myung Soo , Lee Chang Han 
Published: July 2008

AbstractRecently launched in a limited number of countries, digital multimedia broadcasting (DMB) is a brand new mobile service that uses the most advanced IT technology. Analyzing data collected from Korea, Japan, and Germany, this study investigates the relationship between attitudes, and their antecedents, toward using a DMB service and the intention of using it. Results of the study indicate that permanent access, entertainment, and social interaction have a positive influence on attitudes toward using DMB, and that those attitudes positively influence consumers' intention to do so, as do self‐efficacy and consumer perceptions of DMB as an innovation. Some differences in consumer behavior toward DMB service were also found among the three countries. From these findings, practical implications are drawn. © 2008 Wiley Periodicals, Inc.
Comparing consumer responses to advertising and non‐advertising mobile communications
Authors: Nasco Suzanne Altobello , Bruner Gordon C. 
Published: July 2008

AbstractWith a variety of mobile content, such as weather, sports, and commercial ads, available for consumers to access on wireless devices, it is important to explore the effect of presentation modalities on consumers' ability to retain the information and on consumers' perception of the content. Three messages were presented on a mobile device to 116 respondents via six presentation modalities that combined text, audio, static pictures, and/or video. Strong content effects were found, such that weather information was perceived as most important, most involving, and most likely to influence future mobile usage. Modality effects influenced recall, with complementary modes (visual and audio) facilitating recall of the commercial ad, but hindered recall of weather information. Implications for marketers, content designers, and mobile service providers are discussed. © 2008 Wiley Periodicals, Inc.
Synthesis and Electrooptic Properties of Poly(2,6‐anthracenevinylene)s
Authors: Xu Jun , Fang Yujie , Ren Peihua , Zhang Haichang , Guo Erqian , Yang Wenjun 
Published: July 2008

AbstractHigh molecular weight poly(9,10‐bis(p‐(2‐ethylhexyloxy)phenyl)‐2,6‐anthracenevinylene) (2,6‐PAV) was synthesized with 2,6‐dimethylanthraquinone as a key intermediate. The as‐synthesized polymer is readily soluble in common organic solvents and can be used for spin‐coating. The as‐synthesized polymer exhibits a broad absorption band ranging from 280 to 520 nm and a bluish green emission band with a peak at 500 nm. The polymer shows good thermal stability, and no distinct glass transition is observed. A simple device with the configuration ITO/PEDOT:PSS/2,6‐PAV/Ba/Al showed a turn‐on voltage of 4.8 V and a maximal brightness of 340 cd · m−2.magnified image
Modeling Studies of the Phase Behavior of Monomer/Polymer/Disk Composites
Authors: Torrens Francisco , Gómez Clara M. , León Luis M. , Abad Concepción , Campos Agustín 
Published: July 2008

AbstractThe model developed by Balazs et al. to explain the phase behavior of polymer/clay composites is extended to monomer/polymer/clay composites, obtaining an expression for the free energy of a monomer/polymer/thin‐disk mixture. By minimizing the free energy and calculating the chemical potentials of the three system components, phase diagrams for the monomer/disk and monomer/polymer/disk mixtures are contructed. Through the evolution and comparison of these diagrams, the effects of nanodisk size, polymer molecular mass and interaction parameters (temperature) on mixture stability and attained morphology are then studied.magnified image
Dynamics of Phase Separation in Polymer Blends Revisited: Morphology, Spinodal, Noise, and Nucleation
Authors: Fiałkowski Marcin , Hołyst Robert 
Published: July 2008

AbstractThe properties of the model B of mesoscopic dynamic with the Flory–Huggins free energy for the homopolymer blend are discussed. We focus on the rescaling of the spatial coordinates in the model and demonstrate that the commonly used rescaling of the spatial coordinates by the function vanishing at the spinodal leads to the unphysical pinning of the domains. The proper rescaling function for the spatial variables which avoids the unphysical pinning of the domain growth at the spinodal is proposed. We discuss in detail the evolution of morphological measures during separation in homopolymer blends and the problem of nucleation close to the spinodal.magnified image