Papers by Keyword: Monte-Carlo

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Authors: L.V. Elnikova
Abstract: We propose the Ising-like model treatment for phase transitions in pseudoquaternary solution of SDS (sodium dodecylsulfate), toluene, butanol (cosurfactant) and brine (NaCl), that was investigated by neutron spin echo spectroscopy [1] by Molle and coworkers. We compare the relaxation time and diffusion coefficient in the different kinds of droplet cellular structures in dependence on the correlation length, evaluated by lattice Monte Carlo technique.
Authors: Xiu Kai Yuan, Zhen Zhou Lu
Abstract: On the basis of Markov chain simulation, an efficient method is presented to analyze reliability sensitivity of structure. In the presented method, Markov chain is employed to draw the samples distributed in the failure region, and these samples are fitted in a form of hyperplane by the weighted regression. By use of the regressed hyperplane, it is convenient to complete the sensitivities of the failure probability with respect to the distribution parameters of basic random variables by the available method. The presented method is applied to some examples to validate its accuracy and efficiency. The obtained results show that the presented reliability sensitivity analysis method is far more efficient than Monte Carlo based method.
Authors: H.Y. Chin, C.C. Ling, S. Fung, C.D. Beling
Authors: Carlos Pascual-Izarra, Aurelia W. Dong, Steven J. Pas, Ben J. Boyd, C.J. Drummond, Anita J. Hill
Abstract: Self-assembled amphiphile systems are utilized in a wide variety of applications including drug delivery and energy storage. Nano-scale physical and chemical interactions govern the packing of self-assembled amphiphilic molecules, resulting in thermodynamically stable phases of defined geometries. Possible phases include micellar, hexagonal, cubic, lamellar and sponge phases. The internal nano-structure of the amphiphile self-assembly materials plays an important role in the properties of these systems and their application. To date small angle x-ray scattering (SAXS) has been the most common technique used to characterise their structure. We explore positron annihilation lifetime spectroscopy (PALS) as an alternative and/or complementary technique for this purpose, using the phytantriol/water system. While PALS is a well established technique for characterising many materials, the coexistence of aqueous and hydrophobic regions in a soft self-assembled amphiphile material poses a challenge to the analysis and interpretation of the results. In order to alleviate these difficulties we developed a computer program for general-purpose PALS data analysis called PAScual. Amongst the most salient features of this new code are the possibility to perform bounded fits and the option of using advanced algorithms to provide a more robust and unbiased fit: on the one hand, it incorporates a global nonlinear optimisation routine based on the Simulated Annealing algorithm and, on the other hand it gives information on the reliability of the results by means of a Markov Chain Monte-Carlo Bayesian Inference method. In this work we present the newly developed PALS data analysis techniques as well as the results for the phytantriol/water system, comparing them with additional data obtained from complementary techniques.
Authors: Jin Peng Wang, Li Kang, Ping Li, Nian Yu Zou
Abstract: In this paper, how to analyses the downlink performance of the cellular system combining with site diversity operation and antenna diversity is introduced first. On the basis of Gaussian approximation of the interference components, the changes of bit error rate (BER) in the given set of channel is expressed in receiving signals. By using the Monte-Carlo numerical method, the local average BER is then calculated through comparing the conditional BER with the given set of channel gains. The outage probability is considered to measure the distribution of the local average BER and the downlink capacity. Computer simulation results are discussed finally.
Authors: Piotr Warczok, Yao Shan, Michael Schober, Harald Leitner, Ernst Kozeschnik
Abstract: Formation of coherent Cu precipitates in supersaturated ferrite (1.5 at.%Cu) at 500°C is simulated using the Monte Carlo method. Bond energies used in the atomistic simulation are calibrated on the mutual solubilities given on the Fe-rich and Cu-rich side of the Fe(bcc)-Cu(bcc) phase diagram. The spatial extension of the precipitate phase is defined on basis of a composition criterion of the nearest neighbor shells. Various definition conditions are examined in terms of resulting particle densities, mean radii and composition of the precipitates, as well as the composition profiles across the precipitate/matrix interface. The predictions of the simulations are compared with the experimental results from atom probe analysis as well as small angle neutron scattering.
Authors: Irina V. Belova, Graeme E. Murch, Nilindu Muthubandara, Andreas Öchsner
Abstract: The presence of atomic oxygen at internal metal-ceramic oxide interfaces significantly affects the physical properties of the interfaces which in turn affects the bulk properties of the material. We address this problem for the case of a constant source of oxygen at the surface and periodic arrangements of ceramic oxide (MgO) inclusions embedded in a metal (Ag) matrix. We simulate the time-dependence of the oxygen concentration into the material using a newly developed lattice Monte Carlo method that takes into account a constant source of diffusant.
Authors: Irina V. Belova, Graeme E. Murch
Authors: Ya Zhang, Jian Zhong Fu, Zi Chen Chen
Abstract: Measurement process has an important impact on the reliability of measurement. The reliability of measurement is weighed by measurement uncertainty. It is very difficult to estimate the uncertainty in the indirect measurements according to the transfer formula given by GUM (Guide to the Expression of Uncertainty in Measurement). Monte Carlo method was proposed to solve the problem of uncertainty estimation and seek suitable measurement process in the indirect measurements. The mathematical relation between the measurand and the direct measures is established firstly. Then Monte Carlo method was adopted to conduct the sampling and synthesis of measurement uncertainty contributors. At last, the measurement method was evaluated and improved according to Procedure for Uncertainty Management, which is given by next generation of GPS (Geometrical Product Specification). Experimental result shows that Monte Carlo Simulation method has a good application foreground in the uncertainty estimation and measurement process design.
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