317 research outputs found
Vapor-induced swelling of supported methacrylic and siloxane polymer films: Determination of interaction parameters
No full textWhite light reflectance spectroscopy is applied to monitor vapor-induced thickness changes of polymer films, supported on suitable silicon substrates. Assuming unidirectional swelling due to the constraining support, the equilibrium volume swelling of four methacrylic polymers and two siloxane-based copolymers upon exposure to various activities of water, methanol, ethanol, and ethyl acetate vapor, at 30°C is evaluated. The deduced sorption isotherms were fitted to the Flory-Huggins equation and interaction parameters, as well as solubility coefficients at infinite solute dilution, were deduced for each binary system. The relative sorption capacity of the different classes of polymers toward the four vapors are in line with the expected solubility interactions between solvent and solute. © 2009 Wiley Periodicals, Inc
Polymer-BaTiO 3 composites: Dielectric constant and vapor sensing properties in chemocapacitor applications
No full textCONFIRMATORY FACTOR ANALYSIS AND ESTIMATOR COMPARISON OF TWO SHORT FORMS OF AN IRRATIONAL AND RATIONAL BELIEFS SCALE Author(s): Joanne Raptis
No full textThe present study examined two abbreviated versions of the Attitudes and Beliefs Scale-2 (ABS-2) to compare their factor structure and ability to achieve model fit to the data. The original scale, a measure of irrational and rational beliefs as defined by REBT theory, was designed with 72 items reflecting irrational and rational beliefs and each involving one of four cognitive processes and one of three content areas. The ABS-2 had been criticized for its length and the inconsistency of findings regarding its factor structure. Two groups of researchers independently created short forms of the ABS-2 using 24 of the original items. One scale used the items with the highest factor loadings, while the other also prioritized maintaining balance across all dimensions. To also explore the effects of using different estimators, the authors ran Confirmatory Factor Analyses (CFAs) for each short form twice, once using the Maximum Likelihood Robust (MLR) estimator and once using Diagonally Weighted Least Squares (DWLS). The sample consisted of over 1500 participants that included university students, psychotherapy outpatients, and individuals in a drug rehabilitation program. Results showed that both scales yielded virtually equal and excellent fit indices when using the DWLS estimator but not when using MLR. The model with the best fit was an eight-factor bifactor model with factors for the irrational and rational cognitive processes and a general factor. Two other models also yielded especially excellent fit, including a two-factor bifactor model for irrationality and rationality as well as a second-order model with items loading on either one of the four irrational cognitive processes and then a second-order irrationality factor or on one of the four rational cognitive processes and a second-order rationality factor. Ultimately, the results suggest that the assessment can provide meaningful subscales for scores of the total, irrationality, rationality, cognitive processes, and content domains. Additionally, the findings highlight the importance of critically considering one’s data and selecting an appropriate estimator as opposed to relying on default settings. Implications for the assessment of irrational and rational beliefs, furthering REBT research, and targeting treatment to client presentation across the three dimensions are discussed
Finitary Čech-de Rham cohomology
No full textThe present paper continues (Mallios & Rapfis, International Journal of Theoretical Physics, 2001, 40, 1885) and studies the curved finitary spacetime sheaves of incidence algebras presented therein from a Čech cohomological perspective. In particular, we entertain the possibility of constructing a nontrivial de Rham complex on these finite dimensional algebra sheaves along the lines of the first author's axiomatic approach to differential geometry via the theory of vector and algebra sheaves (Mallios, Geometry of Vector Sheaves. An Axiomtic Approach to Differential Geometry, Vols. 1-2, Kluwer, Dordrecht, 1998a; Mathematica Japonica (International Plaza), 1998b, 48, 93). The upshot of this study is that important "classical" differential geometric constructions and results usually thought of as being intimately associated with C∞-smooth manifolds carry through, virtually unaltered, to the finitary-algebraic regime with the help of some quite universal, because abstract, ideas taken mainly from sheaf-cohomology as developed in Mallios (1998a,b). At the end of the paper, and due to the fact that the incidence algebras involved have been interpreted as quantum causal sets (Raptis, International Journal of Theoretical Physics, 2000, 39, 1233; Mallios & Rapfis, 2001), we discuss how these ideas may be used in certain aspects of current research on discrete Lorentzian quantum gravity
Vapor sorption in thin supported polymer films studied by white light interferometry
No full textIn the present study, we apply a white light interferometric methodology to study sorption of moisture and methanol vapor in thin films of poly(2-hydroxyethyl methacrylate) [PHEMA] and poly(methyl methacrylate) [PMMA], supported on oxidized silicon wafers. The measured equilibrium thickness expansion of each film, exposed to different activities of the vapor penetrant, is used to determine the sorption isotherm of the system. Results for relatively thick films (100 nm < Lo< 600 nm) are compared with corresponding literature data for bulk, free-standing films, obtained by direct gravimetric methods. Furthermore, PMMA films of thicknesses lower than 100 nm were employed in order to study the effect of the dry film's thickness, and of substrate, on fractional swelling. © 2006 Elsevier Ltd. All rights reserved
A Heuristic Philosophical Discourse on Various Applications of Abstract Differential Geometry in Quantum Gravity Research
No full textIn the present paper, we outline and expound the fundamental and novel qualitative-cum-philosophical premises, principles, ideas, concepts, constructions and results that originate from our ongoing research project of applying the conceptual panoply and the technical machinery of Abstract Differential Geometry (ADG) to various persistently outstanding issues in Quantum Gravity (QG) research. At the end of the paper, we discuss the potential philosophical repercussions of two possible future research routes that the main stream of our applications of ADG to QG may bifurcate towards in view of three independent, but overlapping, research papers that are currently under development.Corrected, updated and slightly expanded Version II of the paper, to replace Version
Functoriality in Finitary Vacuum Einstein Gravity and Free Yang-Mills Theories from an Abstract Differential Geometric Perspective
No full textWe continue ongoing research work on applying the homological algebraic
conceptual and technical machinery of Abstract Differential Geometry towards
formulating a finitary, causal and quantal version of vacuum Einstein
Lorentzian gravity and free Yang-Mills theories.Comment: This is an invited paper contribution to a Special Volume titled
`Physical Geometry: Unravelling the Weave of Quantum Geometry' in memory and
honour of Professor Anastasios Mallios, edited by Dr Elias Zafiris. Extended
latest version includes two Addenda and an Appendix at the bac
Multiplicatively Ordered and Directed Hybrid Jordan-Lie Superalgebra
No full textA new algebra, hitherto not encountered in the usual Lie algebraic varieties or supervarieties, is introduced. The paper explores the rich and novel structure of the algebra, and it compares it on the one hand with the Jordan-Lie Superalgebras studied by Okubo and Kamiya, and on the other, with the four usual Euclidean division rings of the reals (R), the complexes (C), the quaternions (H) and the octonions (O), key algebraic properties of which the algebra is seen to combine, alter, extend and generalise. A potential physical application of the algebra is briefly alluded to at the end.arXiv admin note: substantial text overlap with arXiv:math-ph/011003
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