bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation on the oxidation behaviour of gamma titanium aluminides coated with thermal barrier coatings
Authors: Braun R. , Fröhlich M. , Ebach‐Stahl A. , Leyens C. 
Published: July 2008

AbstractIn the present study, the applicability of thermal barrier coatings (TBCs) on γ‐TiAl alloys was investigated. Two alloys with the chemical compositions of Ti‐45Al‐8Nb‐0.2B‐0.15C and Ti‐45Al‐1Cr‐6Nb‐0.4W‐0.2B‐0.5C‐0.2Si were used. Before TBC deposition, the specimens were pre‐oxidised in laboratory air or low partial pressure oxygen atmosphere. Yttria partially stabilised zirconia top coats were then deposited using electron‐beam physical vapour deposition (EB‐PVD). The oxidation behaviour of the γ‐TiAl specimens with TBC was studied by cyclic oxidation testing in air at 850 and 900 °C. Post‐oxidation analysis of the coating systems was performed using scanning electron microscopy with energy‐dispersive X‐ray spectroscopy (EDS). No spallation of the TBC was observed for pre‐oxidised specimens of both alloys when exposed to air at 850 °C for 1100 cycles of 1 h dwell time at high temperature. SEM micrographs of the thermally grown oxide scale revealed outer mixed TiO2/Al2O3 protrusions with a columnar structure. The protrusions contained small particles of zirconia and a low amount of about 0.5 at% zirconium was measured by EDS analysis throughout this outer oxide mixture. The TBCs exhibited excellent adherence on the oxide scale. Intercolumnar gaps and pores in the root area of the TBC were filled with titania and alumina. Below the outer columnar oxide scale, a broad porous zone of predominant titania was observed. The transition region between the oxide scale and substrate consisted of a discontinuous nitride layer intermixed with alumina particles and intermetallic phases rich in niobium formed at the nitride layer/substrate interface. When thermally cycled at 900 °C, the oxide scales on the alloy Ti‐45Al‐8Nb‐0.2B‐0.15C pre‐oxidised in low partial pressure oxygen spalled off after 540 cycles. For the sample with TBC, spallation was observed after 810 cycles. Failure occurred in the thermally grown oxide near the oxide/nitride layer interface. Microstructural examinations revealed again oxide scales with columnar structure beneath the zirconia top coat and good adherence of the TBC on the thermally grown oxides formed at 900 °C.
The role that bond coat depletion of aluminum has on the lifetime of APS‐TBC under oxidizing conditions
Authors: Renusch D. , Schorr M. , Schütze M. 
Published: July 2008

AbstractBond coat oxidation as well as bond coat depletion of Al are still believed to be a major degradation mechanism with respect to the lifetime of thermal barrier coating (TBC) systems. In this study the top coat lifetime is described as being limited by both bond coat depletion of Al and mechanical failure of the top coat. The empirical results are introduced by considering three spallation cases, namely, Al depletion failure, thermal fatigue failure, and thermal aging failure. Al depletion failure occurs when the Al content within the bond coat reaches a critical value. In this paper bond coat depletion of Al is modeled by considering the diffusion of Al into both the thermally grown oxide (TGO) and substrate. The diffusion model results are compared to Al concentration profiles measured with an electron beam microprobe. These measured results are from oxidized air plasma sprayed TBC systems (APS‐TBC) with vacuum plasma sprayed (VPS) bond coats for exposures up to 5000 h in the temperature range of 950–1100 °C. This paper focuses on the Al depletion failure and how it relates to top coat spallation.
Behaviour of NiAl APS‐coatings in chlorine‐containing atmospheres
Authors: Latreche H. , Doublet S. , Tegeder G. , Wolf G. , Masset P. , Weber T. , Schütze M. 
Published: July 2008

AbstractDue to their thermal expansion coefficient being close to those of ferritic steels, NiAl atmospheric plasma spraying (APS)‐coatings have been chosen to be tested in chloridizing atmosphere. A new type of quasi‐stability diagram which couples thermodynamic and kinetic approaches was developed to define the stability domains of the pure metals aluminium and nickel in dynamic chlorine‐ and oxygen‐containing atmospheres. NiAl APS‐coatings (300 µm) with low porosity on steels were applied and tested in an atmosphere containing 0.2 v/o chlorine and 3 ppm oxygen. After 280 h of exposure one quarter of the outer coating was transformed into a protective alumina layer. Much nickel depletion, due to the evaporation of nickel chlorides, was observed.
Parameters governing the reduction of oxide layers on Inconel 617 in impure VHTR He atmosphere
Authors: Chapovaloff J. , Kaczorowski D. , Girardin G. 
Published: July 2008

AbstractThe very high temperature reactor (VHTR) has been selected as among the Generation IV nuclear power system. The coolant, namely helium, has been shown to contain low level of oxidizing as well as carbon‐bearing impurities (such as H2, CO (and CO2), CH4, N2 ranging from a few microbars to hundreds of microbars and water vapour in the microbar range) that can interact with metals at high temperature. In this specific gas phase, there is a competition between the formation of protective oxide scales and deleterious reactions towards carbon. A possible oxide layer reduction could be observed in a particular case detailed in this paper. This destruction of the oxide can imply consequences on the behaviour of the alloy as strong carburization or deep internal oxidation could occur. The influence of the level of impurities was analysed through a parametric approach. The experiments were carried out in a purpose‐designed device that allows the control of low impurity partial pressures.
Oxidation of Cr–C electroplating between 400 and 900 °C in air
Authors: Lee D. B. 
Published: July 2008

AbstractThe high temperature oxidation of Cr–C electroplated on a steel substrate was studied at 400–900 °C in air. Before oxidation, the deposit consisted primarily of C‐supersaturated, amorphous Cr grains. During oxidation, oxygen diffused inward, while Cr and the substrate elements such as Fe diffused outward. Carbon tended to escape, but some of it remained and existed mainly as graphite throughout the oxide layer and the Cr–C electrodeposit. A Cr2O3 oxide layer having dissolved Fe ions formed on the unoxidized, crystalline Cr layer. The Cr–C electrodeposit oxidized approximately parabolically, with a faster oxidation rate than bulk Cr.
Modelling of the long time stability of the fluorine effect in TiAl oxidation
Authors: Zschau H.‐E. , Schütze M. 
Published: July 2008

AbstractRecently the target temperature of components manufactured from γ‐TiAl alloys like turbine blades, turbocharger rotors or automotive valves has been increased to 900 °C. However, there is an insufficient oxidation resistance above 750 °C. One method used to improve the γ‐TiAl oxidation behaviour is the so‐called fluorine microalloying effect. After application of fluorine to the TiAl surface by ion implantation or treatment with diluted HF and oxidation at 900 °C in air a dense alumina layer is formed. However, after the treatments a distinct loss of fluorine was observed during heating and within the first hours of oxidation. In this work, the long time behaviour during isothermal and cyclic oxidation up to 1500 h/900 °C/air was investigated showing a slow fluorine decrease. The alumina layer acts as a diffusion barrier for fluorine, whereas fluorine diffuses into the metal. The diffusion coefficient was calculated. The results fit the theoretical model of the fluorine effect.
Morphology and Melt Crystallization of PCL‐PEG Diblock Copolymers
Authors: Xu Ying , He Yong , Wei Jia , Fan Zhongyong , Li Suming 
Published: July 2008

AbstractROP of PCL was realized in the presence of mPEG with $\overline M _{\rm n}$ = 5 000, using Zn(La)2 as a catalyst. The resulting diblock copolymers with molar ratios of the CL/EO repeat units from 0.2–5.0 were characterized by DSC, WAXD, SEC, and 1H NMR. Melt crystallization was studied and analyzed with the Avrami equation. The spherulite growth rate G was determined at different crystallization temperatures. The G values were found to range between those of mPEG and PCL homopolymers. The morphology of an isothermally crystallized sample with CL/EO = 0.5 was examined. Spherulites with PCL embedded in PEG were observed, in contrast to concentric spherulites reported in the literature.magnified image
Photosensitive High‐Refractive‐Index Poly(acrylic acid)‐graft‐Poly(ethylene glycol methacrylate) Nanocrystalline Titania Hybrid Films
Authors: Su Hung‐Wen , Chen Wen‐Chang 
Published: July 2008

AbstractIn this study, photosensitive high‐refractive‐index poly(acrylic acid)‐graft‐poly(ethylene glycol methacrylate)‐(3‐trimethoxysilyl propyl methacrylate)‐modified titania hybrid materials were synthesized, followed by hydrothermal treatment. Nanocrystalline titania in the hybrid materials, analyzed by high‐resolution transmission electron microscopy (HRTEM), X‐ray diffraction (XRD) and small‐angle X‐ray scattering (SAXS), had domain sizes of around 3–7 nm and had a more‐compact anatase structure at a higher titania content. The prepared optically transparent films had a refractive index in the range of 1.528–1.803 as the titania content increased from 5.6 to 61.9 wt.‐%. A fine pattern with a line width of 20 µm was produced by a direct lithographic process on the hybrid films. The present study demonstrates a novel approach for preparing photosensitive high‐refractive‐index hybrid materials with patternability.magnified image
Groupwise density cannot be much bigger than the unbounded number
Authors: Shelah Saharon 
Published: July 2008

AbstractWe prove that g (the groupwise density number) is smaller or equal to 𝔟+, the successor of the minimal cardinality of an unbounded subset of ωω. This is true even for the version of 𝔤 for groupwise dense ideals. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Measurable groups of low dimension
Authors: Elwes Richard , Ryten Mark 
Published: July 2008

AbstractWe consider low‐dimensional groups and group‐actions that are definable in a supersimple theory of finite rank. We show that any rank 1 unimodular group is (finite‐by‐Abelian)‐by‐finite, and that any 2‐dimensional asymptotic group is soluble‐by‐finite. We obtain a field‐interpretation theorem for certain measurable groups, and give an analysis of minimal normal subgroups and socles in groups definable in a supersimple theory of finite rank where infinity is definable. We prove a primitivity theorem for measurable group actions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On triangular norm based axiomatic extensions of the weak nilpotent minimum logic
Authors: Noguera Carles , Esteva Francesc , Gispert Joan 
Published: July 2008

AbstractIn this paper we carry out an algebraic investigation of the weak nilpotent minimum logic (WNM) and its t‐norm based axiomatic extensions. We consider the algebraic counterpart of WNM, the variety of WNM‐algebras (𝕎ℕ𝕄) and prove that it is locally finite, so all its subvarieties are generated by finite chains. We give criteria to compare varieties generated by finite families of WNM‐chains, in particular varieties generated by standard WNM‐chains, or equivalently t‐norm based axiomatic extensions of WNM, and we study their standard completeness properties. We also characterize the generic WNM‐chains, i. e. those that generate the variety 𝕎ℕ𝕄, and we give finite axiomatizations for some t‐norm based extensions of WNM. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determinant factors of mobile‐based word‐of‐mouth campaign referral among Japanese adolescents
Authors: Okazaki Shintaro 
Published: July 2008

AbstractThis study addresses why Japanese teenagers participate in mobilebased word‐of‐mouth (WOM) campaigns. It is posited that commitment to the promoted brand, relationship with the mobile device, and group–person connectivity act as antecedents of two primary gratifications of the campaign, entertainment value and purposive value, which in turn determine the direction and strength of the attitude–intention–behavior chain. A “real” mobile campaign was used as stimulus. Based on a random sampling method, 22,500 structured questionnaires were sent to young consumers, 13–18 years old, via mobile device. Our data fit the proposed model fairly well, and all hypothesized paths are supported. There are significant differences in the strength of the paths between teenagers who learned of the campaign from non‐WOM sources (i.e., content‐based Web sites and e‐mail magazines) versus WOM sources (pass‐along e‐mail and direct referral). In closing, theoretical and managerial implications are discussed and important limitations are recognized. © 2008 Wiley Periodicals, Inc.
Comparing the perceived value of information and entertainment mobile services
Authors: Pihlström Minna , Brush Gregory J. 
Published: July 2008

AbstractThe importance of perceived value in customer decision making is well known. However, few studies assess empirically the direct effects of various perceived value dimensions on post‐purchase behavior. This article examines differences between information and entertainment mobile content service users in how their value perceptions influence intentions to repurchase, intentions to spread positive word of mouth, and willingness to pay a price premium. The direct effects of four value dimensions are analyzed: monetary, convenience, emotional, and social value. Within this study we also propose and test the antecedent effects of conditional and epistemic value. This approach advances the value literature through increasing our understanding of how individual value dimensions influence post‐purchase behavior and of the role of epistemic and conditional value. Using a sample of 579 mobile service users, results are analyzed with multi‐group structural equation modeling. The findings support use of multidimensional value and loyalty constructs to identify differences between service user groups, and argue for the use of differentiated value‐based marketing strategies for entertainment and information mobile services. © 2008 Wiley Periodicals, Inc.
Gearing up for mobile advertising: A cross‐cultural examination of key factors that drive mobile messages home to consumers
Authors: Choi Yung Kyun , Hwang Jang‐Sun , McMillan Sally J. 
Published: July 2008

AbstractMobile advertising is gearing up for success, but researchers and practitioners need to understand how to measure the effectiveness of this advertising form—particularly the factors that drive mobile messages home in different cultures. This study identifies key measures of effectiveness as well as antecedent variables in the context of 629 Korean and American consumers. Entertainment and credibility were key factors predicting positive attitude and purchase intention among both Koreans and Americans. However, this study found multiple cross‐cultural differences—particularly in informativeness, perceived interactivity, and the value of mobile advertising. Theoretical explanations and practical implications are suggested. © 2008 Wiley Periodicals, Inc.
An examination of factors influencing consumer adoption of short message service (SMS)
Authors: Kim Gil Son , Park Se‐Bum , Oh Jungsuk 
Published: July 2008

AbstractFactors related to consumer adoption of short message service (SMS) are analyzed in this article. Our structural equation model identifies perceived enjoyment (PENJ), perceived monetary value (PMV), perceived usefulness (PU), and perceived ease of use (PEU) as four major factors that directly affect Korean mobile phone users' SMS adoption. We also find that network factor (NET), interface convenience (IC), and context controllability (CC) have significant indirect impacts on consumer adoption of SMS through their respective paths on perceived usefulness (PU) and perceived ease of use (PEU). Our findings demonstrate that SMS must be perceived as enjoyable and pleasant, because consumers' motivation to use enjoyable and pleasant services like SMS enhances their value perceptions of SMS such as perceived usefulness (PU) and perceived ease of use (PEU). The findings also suggest that more convenient and easier‐to‐use system interfaces, greater context controllability across various SMS usage contexts, and greater network externalities can facilitate SMS adoption in the future. © 2008 Wiley Periodicals, Inc.
Understanding the acceptance of mobile SMS advertising among young Chinese consumers
Authors: Zhang Jing , Mao En 
Published: July 2008

AbstractThis study examined the acceptance of SMS advertising, an increasingly popular mobile marketing practice, among young Chinese consumers. A modified technology acceptance model (TAM) was developed to test the intention to use SMS advertising—that is, to read the advertising message and take action as suggested by the message. Data were collected from 262 mobile phone users who were 21–35 years old. The research model was analyzed using structural equation modeling (SEM). Results showed that the two key determinants of TAM, the perceived usefulness and perceived ease of use of SMS advertising messages, predicted the intention to use them. In addition, trust in SMS advertising and subjective norms also contributed to the intention to use. The antecedents and consequents of perceived usefulness and trust were also examined in the SMS advertising context. Overall, the model is well supported. This study represents a novel approach to studying the effectiveness of SMS advertising by applying a model developed in information technology. It also revitalizes the theory of reasoned action in advertising research. The findings have important implications for studying advertising and marketing activities that utilize new media. In addition, practical implications are discussed and directions for future research are suggested. © 2008 Wiley Periodicals, Inc.
Kinetic Investigations on the Polymerization of 2‐Oxazolines Using Pluritriflate Initators
Authors: Luxenhofer Robert , Bezen Manuela , Jordan Rainer 
Published: July 2008

AbstractIn our ongoing efforts to develop poly(2‐oxazoline)s (POx) for biomedical applications, we report on the preparation of defined, star‐like hydrophilic POx. Using pluritriflate initiators, we show, through online kinetic measurements by gas chromatography, that multiple initiating groups are of equal reactivity for the initiation of the polymerization of 2‐oxazolines. The overall polymerization rate increases linearly with the number of initiator functions per molecule. Thus, all initiating moieties are of the same reactivity and all arms grow at the same rate. This is crucial for the establishment of a meaningful structure‐property relationship for polymers of star architectures.magnified image
When electrons meet molecular ions and what happens next: Dissociative recombination from interstellar molecular clouds to internal combustion engines
Authors: Thomas Richard D. 
Published: July 2008

AbstractThe interaction of matter with its environment is the driving force behind the evolution of 99% of the observed matter in the universe. The majority of the visible universe exists in a state of weak ionization, the so called fourth state of matter: plasma. Plasmas are ubiquitous, from those occurring naturally; interstellar molecular clouds, cometary comae, circumstellar shells, to those which are anthropic in origin; flames, combustion engines and fusion reactors. The evolution of these plasmas is driven by the interaction of the plasma constituents, the ions, and the electrons. One of the most important subsets of these reactions is electron–molecular ion recombination. This process is significant for two very important reasons. It is an ionization reducing reaction, removing two ionised species and producing neutral products. Furthermore, these products may themselves be reactive radical species which can then further drive the evolution of the plasma. The rate at which the electron reacts with the ion depends on many parameters, for examples the collision energy, the internal energy of the ion, and the structure of the ion itself. Measuring these properties together with the manner in which the system breaks up is therefore critical if the evolution of the environment is to be understood at all. Several techniques have been developed to study just such reactions to obtain the necessary information on the parameters. In this paper the focus will be on one the most recently developed of these, the Ion Storage Ring, together with the detection tools and techniques used to extract the necessary information from the reaction. © 2008 Wiley Periodicals, Inc., Mass Spec Rev 27: 485–530, 2008
Mass spectrometry‐based proteomics in reproductive medicine
Authors: Kolialexi Aggeliki , Mavrou Ariadni , Spyrou George , Tsangaris George Th. 
Published: July 2008

AbstractThe emergence of powerful mass spectrometry‐based proteomic techniques has added a new dimension to the field of biomedical research. Application of these high throughput methodologies in pregnancy‐related pathology has contributed to the comprehension of the underlying pathophysiologies and the successful identification of relevant protein biomarkers that can potentially change early diagnosis and treatment of several medical conditions related to human pregnancy. Most of the existing research on human reproduction and gestation has focused on follicular fluid, cervical/vaginal fluid, and amniotic fluid. Although proteome technologies in reproductive medicine research are not as yet widely applied, characterization of the proteome of reproductive fluids can be expected to significantly improve maternal healthcare. This article aims to summarize the applications of mass spectrometry based technology on the most important and specific biological fluids related to reproduction and gestation. © 2008 Wiley Periodicals, Inc., Mass Spec Rev 27: 624–634, 2008
Plant proteomics: Concepts, applications, and novel strategies for data interpretation
Authors: Baginsky Sacha 
Published: July 2008

AbstractProteomics is an essential source of information about biological systems because it generates knowledge about the concentrations, interactions, functions, and catalytic activities of proteins, which are the major structural and functional determinants of cells. In the last few years significant technology development has taken place both at the level of data analysis software and mass spectrometry hardware. Conceptual progress in proteomics has made possible the analysis of entire proteomes at previously unprecedented density and accuracy. New concepts have emerged that comprise quantitative analyses of full proteomes, database‐independent protein identification strategies, targeted quantitative proteomics approaches with proteotypic peptides and the systematic analysis of an increasing number of posttranslational modifications at high temporal and spatial resolution. Although plant proteomics is making progress, there are still several analytical challenges that await experimental and conceptual solutions. With this review I will highlight the current status of plant proteomics and put it into the context of the aforementioned conceptual progress in the field, illustrate some of the plant‐specific challenges and present my view on the great opportunities for plant systems biology offered by proteomics. © 2008 Wiley Periodicals, Inc., Mass Spec Rev 28:93–120, 2009