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Monte-Carlo Method (monte-carlo + method)
Selected AbstractsTechnical basis on structural fire resistance design in building standards law of JapanFIRE AND MATERIALS, Issue 2-4 2004Kazunori Harada Abstract Structural fire resistance design method came into effect due to the revision of Japan's building code (building standards law of Japan) in June 2001. The method includes standard methods to calculate (1) fire exposure to structural elements, (2) temperature rise of steel and RC elements during fire exposure and (3) structural end points such as ultimate steel temperature for buckling of columns, bending failure of beams and so on. This paper discusses the technical basis for design methods especially focused on steel framed buildings. The calculated values by design equations were compared with experimental values in order to examine the redundancies implied. In the final stage, all the redundancies were combined by Monte-Carlo method and first-order moment method (AFORM). Target safety index and corresponding partial safety factors were discussed. Copyright © 2004 John Wiley & Sons, Ltd. [source] Large eddy simulation (2D) of spatially developing mixing layer using vortex-in-cell for flow field and filtered probability density function for scalar fieldINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 1 2006J. K. Wang Abstract A large eddy simulation based on filtered vorticity transport equation has been coupled with filtered probability density function transport equation for scalar field, to predict the velocity and passive scalar fields. The filtered vorticity transport has been formulated using diffusion-velocity method and then solved using the vortex method. The methodology has been tested on a spatially growing mixing layer using the two-dimensional vortex-in-cell method in conjunction with both Smagorinsky and dynamic eddy viscosity subgrid scale models for an anisotropic flow. The transport equation for filtered probability density function is solved using the Lagrangian Monte-Carlo method. The unresolved subgrid scale convective term in filtered density function transport is modelled using the gradient diffusion model. The unresolved subgrid scale mixing term is modelled using the modified Curl model. The effects of subgrid scale models on the vorticity contours, mean streamwise velocity profiles, root-mean-square velocity and vorticity fluctuations profiles and negative cross-stream correlations are discussed. Also the characteristics of the passive scalar, i.e. mean concentration profiles, root-mean-square concentration fluctuations profiles and filtered probability density function are presented and compared with previous experimental and numerical works. The sensitivity of the results to the Schmidt number, constant in mixing frequency and inflow boundary conditions are discussed. Copyright © 2005 John Wiley & Sons, Ltd. [source] Reactor performance with primary/secondary swirl intensity and direction in coal gasification processINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 13 2001Han Chang Cho Abstract In order to evaluate the effect of swirl direction and intensity of primary/secondary stream on pulverized coal gasification performance, a numerical study was conducted. Eulerian and Lagrangian approaches are used for the gas and solid phase, respectively. The computation code was formulated with PSI-cell method, k,, model for turbulence flow, Monte-Carlo method for radiative heat transfer, and eddy dissipation model for gas-phase reaction rate. A one-step two-reaction model is employed for the devolatilization of Kideco coal. Flow and reactor performance are varied by primary/secondary swirl intensity and direction. For weak primary swirl, the WSF region is minimized at the secondary vane angle beginning generation of internal recirculation zone and having peak coal burnout. The flame stability is improved at counterswirl rather than coswirl due to its intense shear. Meanwhile, for strong primary swirl, flow distribution and coal burnout are the reverse trend with those of weak swirl and the flame stability is somewhat enhanced at coswirl rather than counterswirl. To improve coal burnout and flame stability, it is confirmed that the swirl condition be proposed for moving the flame front position toward upstream. Copyright © 2001 John Wiley & Sons, Ltd. [source] Mesoscopic Modelling of Polymer-Based Optoelectronic DevicesPLASMA PROCESSES AND POLYMERS, Issue S1 2007Hélder M. C. Barbosa Abstract Substantial progress has been made in fabricating optoelectronic devices using polymers as an active material. In polymer light emitting diodes (PLEDs), a balanced injection of electrons and holes from the electrodes is fundamental to increase their performance. Using a mesoscopic model based on a generalized Monte-Carlo method, we studied the influence of changing zero-field barrier heights at both electrode,polymer interfaces in the performance of a PLED with an active layer of poly(para -phenylenevinylene) (PPV). Our results show that by controlling the electrodes work functions it is possible to tune the region inside the device where charge recombination preferentially takes place. [source] Conformational Analysis of R207910, a New Drug Candidate for the Treatment of Tuberculosis, by a Combined NMR and Molecular Modeling ApproachCHEMICAL BIOLOGY & DRUG DESIGN, Issue 2 2006Sandrine Gaurrand R207910 is an enantiomeric compound from a new class of antimycobacterial agents, the diarylquinolines [Science; 307:223 (2005)]. As enantiospecific interaction is required for biologic activity, we have undertaken a combined nuclear magnetic resonance and molecular modeling study to gain new insights into its conformation in solution and its absolute configuration. A conformational analysis using a Monte-Carlo method has been performed on each of the four possible stereomers of this compound leading to the identification of their most stable conformation. Additional ab initio calculation was performed with emphasis on the strength of the observed intramolecular hydrogen bond. Simultaneously, a complete structural identification has been carried out by a set of monodimensional and bidimensional 1H- 13C-NMR experiments. Determination of inter-proton distances has been achieved by a series of 1H- 1H ROESY NMR experiments with different mixing times followed by a volume quantification of the correlations peaks. These experimental data were compared with the theoretical distances obtained from the conformational analysis. The remarkable match shows that R207910 adopts one of the low-energy conformations predicted by molecular modeling and belongs to the (RS, SR) couple of diastereoisomers. A posteriori validation of our approach has been performed by X-ray structure determination that concluded for the RS configuration. [source] How should we quantify the performance of KPro's?ACTA OPHTHALMOLOGICA, Issue 2009Purpose To report a method of standardized data collection and reporting and statistical assessment that can be used for all KPro´s available on the market. The database (will be presented) should be , Usable for different types of KPro´s , Easily adaptable to changes in technique , Allow for complete entry of relevant data Methods Visual Acuity data should be reported in different international surgical centres in a standardized manner: Best spectacle corrected VA, unless BCVA only possible with CL (> useful time of wear). A complete entry of all relevant data is possible in this database. The statistical analysis should be agreed upon by all centres. For Survival Time = Retention of KPro > the Kaplan-Meier method For Visual Acuity over the Course of Time > the Monte-Carlo method Results A database will be demonstrated that can be used free of charge by all KPro centres interested. The VISUAL ACUITY BY TIME- INDEX (VAT- Index) will also be presented, whose theoretical basis published in: Journal of Theoretical Medicine, 2002 / 4, 183-190, W. Hitzl and G. Grabner [bdquo]Application of the Monte Carlo Method for the Assessment of Long-term Success in Keratoprosthesis Surgery". Example of its use will be give, based in data, courtesy Barraquer Eye Clinic, Barcelona. Conclusion With the Kaplan-Meier method: + analysis is done quickly, uses all data available, hypotheses tests are available for comparisons and mean and median survival time can be computed - no information about relation between time and best corrected visual acuity and the definition of terminal event is arbitrary to a certain extent. Monte-Carlo method (VAT-index): + Method is based on a so-called non-parametric longitudinal model + Reliabel estimation of relation between time and best corrected visual acuity at any given time point (patient as well as surgeon is basically interested in this relation). + statistically valid analysis and better comparison of different KPro techniques + easy comparison of defined postoperative periods + comparison of different initial clinical findings and diseases possible + long-time follow-up of BCVA - shorter follow-up time as compared with Kaplan-Meier method (e.g. with strict [bdquo]80%data complete" criteria) [source] | ||||||||||