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  • Polymer and Materials Science  (4)
  • Monte Carlo simulations  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Critical wetting in the square Ising model with a boundary field (1990)
    Springer
    Journal of statistical physics 61 (1990), S. 161-178 
    Details
    ISSN: 1572-9613
    Keywords: Critical wetting ; Ising model ; Monte Carlo simulations ; finite-size scaling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Ising square lattice with nearest-neighbor exchangeJ〉0 and a free surface at which a boundary magnetic fieldH 1 acts has a second-order wetting transition. We study the surface excess magnetization and the susceptibility ofL×M lattices by Monte Carlo simulation and probe the critical behavior of this wetting transition, applying finite-size scaling methods. For the cases studied, the results are not consistent with the presumably exactly known values of the critical exponents, because the asymptotic critical region has not yet been reached. Implication of our results for critical wetting in three dimensions and for the application of the present model to adsorbed wetting layers at surface steps are briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01013958
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  • 2
    Electronic Resource
    Electronic Resource
    Finite-Size Scaling in the p-State Mean-Field Potts Glass: A Monte Carlo Investigation (1998)
    Springer
    Journal of statistical physics 92 (1998), S. 57-100 
    Details
    ISSN: 1572-9613
    Keywords: Mean-field Potts glass ; orientational glass ; infinite range interactions ; Monte Carlo simulations ; finite-size scaling ; self-averaging ; first-order transition without latent heat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The p-state mean-field Potts glass with bimodal bond distribution (±J) is studied by Monte Carlo simulations, both for p = 3 and p = 6 states, for system sizes from N = 5 to N = 120 spins, considering particularly the finite-size scaling behavior at the exactly known glass transition temperature T c. It is shown that for p = 3 the moments q (k) of the spin-glass order parameter satisfy a simple scaling behavior, $$q^{(k)} \alpha N^{--k/3} \tilde f_k \{ N^{1/3} (1--T/T_c )\} ,{\text{ }}k = 1,2,3,...,\tilde f_k $$ being the appropriate scaling function and T the temperature. Also the specific heat maxima have a similar behavior, $$c_V^{\max } \alpha {\text{ }}const--N^{--1/3} $$ , while moments of the magnetization scale as $$m^{(k)} \alpha N^{--k/2} $$ . The approach of the positions T max of these specific heat maxima to T c as N → ∞ is nonmonotonic. For p = 6 the results are compatible with a first-order transition, q (k) → (q jump)k as N → ∞ but since the order parameter q jump at T c is rather small, a behavior q (k) ∝ N -k/3 as N → ∞ also is compatible with the data. Thus no firm conclusions on the finite-size behavior of the order parameter can be drawn. The specific heat maxima c V max behave qualitatively in the same way as for p = 3, consistent with the prediction that there is no latent heat. A speculative phenomenological discussion of finite-size scaling for such transitions is given. For small N (N ≤15 for p = 3, N ≤ 12 for p = 6) the Monte Carlo data are compared to exact partition function calculations, and excellent agreement is found. We also discuss ratios $$R_x \equiv [(\langle X\rangle _T - [\langle X\rangle _T ]_{{\text{av}}} )^2 ]_{{\text{av}}} /[\langle X\rangle _T ]_{{\text{av}}}^2 $$ , for various quantities X, to test the possible lack of self-averaging at T c.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1023043602398
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  • 3
    Electronic Resource
    Electronic Resource
    Interfacial Profiles Between Coexisting Phases in Thin Films: Cahn—Hilliard Treatment Versus Capillary Waves (1999)
    Springer
    Journal of statistical physics 95 (1999), S. 1045-1068 
    Details
    ISSN: 1572-9613
    Keywords: polymer mixtures ; concentration profiles ; Cahn—Hilliard theory ; capillary wave Hamiltonian ; self-consistent field theory ; Monte Carlo simulations ; wetting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A symmetric binary mixture (A, B) below its critical temperature T c of unmixing is considered in a thin-film geometry confined between two parallel walls, where it is assumed that one wall prefers A and the other wall prefers B. Then an interface between the coexisting unmixed phases is stabilized, which (above the wetting transition temperature) occurs in the center of the film for an average concentration of c=1/2. We consider how the concentration profile c(z) across the thin film depends on the film thickness D. By Monte Carlo simulation of a lattice model for a polymer mixture it is shown that for relatively small D the width of the interface scales like w ∝ D, while for larger D a crossover to a behavior w ∝ $$\sqrt D $$ occurs. This behavior is explained by phenomenological theories: it is shown that the behavior at small D can be understood by a suitable extension of the Cahn—Hilliard “gradient-square”-type theory, while the behavior for large D can be traced back to the behavior of capillary waves exposed to a short-range potential by the walls. Corrections due to fast concentration variations, as they occur in the strong-segregation limit of a polymer mixture, can be accounted for by self-consistent field theory. Subtle problems occur, however, with respect to the proper combination of these theories with the capillary wave approximation, particularly at intermediate values of D.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004510702716
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  • 4
    Electronic Resource
    Electronic Resource
    Ein neues Zeitstandgerät für Kriechversuche bei wechselnden Belastungen und TemperaturenVortrag, gehalten auf der ACHEMA 1973 in Frankfurt/M. (1974)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 5 (1974), S. 205-208 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: A New Instrument for Measuring Creep under Alternating Loading and Temperature Conditions. It is an established fact that plastics are particularly subject to creep, i. e. deformation over a period of time under load. Under practical conditions unchanged load and constant temperature are seldom realized. The deformations associated with changing mechanical loads cannot generally be derived from the results of ordinary creep tests. In order to be able to study creep behaviour of plastics under intermittent load conditions (i. e. a sequence of loading and unloading), a special instrument has been developed at the Austrian Plastics Institute.The period of time as well as the ratio of loading and unloading phase can be programmed within wide ranges. Creep tests at varying temperatures can also be carried out with this instrument.Under intermittent load very significant differentiation of deformation and fracturing behaviour depending on the polymeric structure has been observed. Comparison of results of ordinary creep with those under intermittent loading at constant temperature shows, that in the case of amorphous thermoplastics destruction by stress crazing and fracture is markedly accelerated. On the other hand semicrystalline thermoplastics have excellent resistance against intermittent load.
    Notes: Es ist allgemein bekannt, daß bei Kunststoffen das Kriechen, die zeitliche Zunahme der Deformation unter Last, besonders stark ausgeprägt ist. Der Fall einer kontinuierlich wirkenden Belastung und konstanter Temperatur ist in der Praxis aber häufig nicht gegeben. Die mit wechselnden mechanischen Belastungen verbundenen Deformationen können im allgemeinen nicht aus den Ergebnissen üblicher Kriechversuche abgeleitet werden. Um das Kriechverhalten von Kunststoffen bei intermittierender Belastung (das ist eine Aufeinanderfolge von Belastungs- und Entlastungsschritten) studieren zu können, wurde im Österreichischen Kunststoffinstitut ein spezielles Gerät entwickelt. Die absolute Länge und auch das Verhältnis von Belastungs- zu Entlastungsphase können in weiten Bereichen programmiert werden. Mit dem gleichen Gerät lassen sich auch Kriechversuche bei wechselnden Temperaturen ausführen.Bei intermittierender Beanspruchung wurde eine sehr starke Differenzierung des Verformungs- und Bruchverhaltens in Abhängigkeit von der Struktur des Kunststoffes festgestellt. Der Vergleich der Ergebnisse mit den bei konstanter Belastung erhaltenen zeigt, daß bei amorphen Plastomeren die Zerstörung durch Spannungsrißbildung bzw. Bruch viel früher erfolgt. Dagegen weisen teilkristalline Plastomere eine ganz ausgezeichnete Widerstandsfähigkeit gegen intermittierende Beanspruchung auf.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19740050407
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  • 5
    Electronic Resource
    Electronic Resource
    Monte Carlo simulations of polymer dynamics: Recent advances (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 1-31 
    Details
    ISSN: 0887-6266
    Keywords: Rouse model ; reptation ; glass transition ; Monte Carlo method ; bond fluctuation model ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A brief review is given of applications of Monte Carlo simulations to study the dynamical properties of coarse-grained models of polymer melts, emphasizing the crossover from the Rouse model toward reptation, and the glass transition. The extent to which Monte Carlo algorithms can mimic the actual chain dynamics is critically examined, and the need for the use of coarse-grained rather than fully atomistic models for such simulations is explained. It is shown that various lattice and continuum models yield qualitatively similar results, and the behavior agrees with the findings of corresponding molecular dynamics simulations and experiments, where available. It is argued that these simulations significantly enhance our understanding of the theoretical concepts on the dynamics of dense macromolecular systems. © 1997 John Wiley & Sons, Inc.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Surface effects on polymer blends and block copolymer melts: Theoretical concepts of surface enrichment, surface induced phase separation and ordering (1995)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 46 (1995), S. 204-225 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Surfaces have a profound effect on the structure and related properties of multiphase polymeric materials, such as polymer mixtures and block copolymer mesophases. In particular, phase transitions in the bulk (unmixing, microphase separation, etc.) may be complemented by surface-induced transitions (formation of wetting layers, surface-directed spinodal decomposition, surface-induced ordering). This review gives a brief introduction to the phenomenological theories of such phenomena, emphasizing the simplest approach based on Flory - Huggins - de Gennes free energy functionals and associated Monte Carlo simulations. More sophisticated theories and recent experiments are mentioned briefly.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1995.010460302
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  • 7
    Electronic Resource
    Electronic Resource
    Characterization of materials in research  -  ceramics and polymers, J. J. Burke and V. Weiss, Eds., Syracuse University Press, Syracuse, N. Y., 1975, 566 pp. (1977)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 15 (1977), S. 635-636 
    Details
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1977.130151018
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