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5th International Conference on engineering Computational Technology, ECT 2006

作者： Bugeda, G. Ródenas, J.J. Pahl, E. Oñate, E. Universitary School of Industrial Technical Engineering of Barcelona EUETIB-UPC Spain Research Center on Vehicles Technology Department of Mechanical and Materials Engineering Polytechnic University of Valencia Spain International Center for Numerical Methods in Engineering CIMNE-UPC Barcelona Spain

ISBN: (纸本)1905088094

The use of evolutionary methods in structural shape optimization requires the structural analysis of an important number of different designs, this making the computational cost of the analysis of each design a critical issue. Each design must be analyzed at a minimum computational cost but ensuring a minimum quality of the results using adapted meshes. Nevertheless, with meshes, obtained from traditional adaptive remeshing strategies, each design is analyzed more than once causing a high computational cost. This work presents a strategy to generate an adapted mesh for each design without the necessity of a full adaptive remeshing procedure for each design. It is based on the use of sensitivity analysis of all magnitudes related with adaptive remeshing (location of nodes, error estimation, ...) with respect to the design variables. The sensitivity analysis is performed only once over a reference geometry and then used to project the results to all other designs to be analyzed. An appropriate adapted mesh is thus generated for each new design in one shot, greatly reducing the computational cost compared with standard strategies. © 2006 Civil-Comp Press.

关键词： Sensitivity analysis

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Classification of power quality considering voltage sags occurred in feeders

Classification of power quality considering voltage sags occ...

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5th International Joint Conference on Computational Intelligence, IJCCI 2013

作者： Góes, Anderson Roges Teixeira Steiner, Maria Teresinha Arns Neto, Pedro José Steiner Graduate Programs in Numerical Methods in Engineering Federal University of Paraná Centro Politécnico CP: 19081 CEP: 81531-990 Curitiba PR Brazil Graduate Program in Industrial and Systems Engineering Pontifical Catholic University of Paraná Rua Imaculada Conceição 1155 Prado Velho CEP: 80.215-901 Curitiba PR Brazil Numerical Methods in Engineering and Industrial Engineering Federal University of Paraná Centro Politécnico CP: 1908 CEP: 81531-990 Curitiba PR Brazil Graduate Programs in Business Administration Federal University of Paraná Av. Pref. Lothario Meissner 632 CEP: 80210-170 Curitiba PR Brazil

ISBN: (纸本)9789898565778

In this paper we propose a methodology to classify Power Quality for feeders, based on sags and by the use of KDD technique, establishing a quality level printed in labels. To support the methodology, it was applied to feeders on a substation located in Curitiba, Paraná, Brazil, based on attributes such as sag length, duration and frequency (number of occurrences on a given period of time). In the search for feeders quality classification, on the Data Mining stage, the main stage on KDD process, three different techniques were used in a comparatively way for pattern recognition: Artificial Neural Networks, Support Vector Machines an Genetic Algorithms. Those techniques presented acceptable results in classification feeders with no possible classification using a simplified method based on maximum number of sags. Thus, by printing the label with information and Quality level, utilities companies can get better organized for mitigation procedures, by establishing clear targets.

关键词： Pattern recognition

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Secondary motion in turbulent flows over superhydrophobic surfaces 8

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8th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2013

作者： Hasegawa, Yosuke Tuerk, Sebastian Stroh, Alexander Daschiel, Getraud Frohnapfel, Bettina Institute of Industrial Science University of Tokyo Komaba 4-6-1 Meguro-ku Tokyo153-8505 Japan Graduate School of Computational Engineering Numerical Methods in Mechanical Engineering Technical University of Darmstadt Dolivostr. 15 Darmstadt64293 Germany Institute of Fluid Mechanics Karlsruhe Institute of Technology Kaiserstr. 10 Karlsruhe76131 Germany

ISBN: (纸本)9780000000002

We investigate the effects of superhydrophobic surface carrying streamwise micro grooves on the flow dynamics and the resultant gain in the flow rate in a fully developed turbulent channel flow under a constant pressure gradient. The superhydrophobic surface is modeled as a flat boundary with alternating no-slip and slip conditions, and a series of direct numerical simulations is performed with systematically changing the spanwise periodicity of the streamwise grooves. It is observed that the alternating no-slip and slip boundary conditions cause a spanwise inhomogeneity of the Reynolds shear stress near the superhydrophobic surface, and consequently generate Prandtl's second kind of secondary flow characterized by coherent streamwise vortices. Accordingly, the instantaneous turbulent flow is decomposed into the spatial-mean, coherent and random components. The detailed turbulent statistics of the three components are obtained and the effect of the secondary flow on the resultant drag reduction is discussed.

关键词： Secondary flow

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Towards the Optimization of Advanced Oxidation Processes Using Machine Learning Modelling: The DIGIT4WATER Project

Towards the Optimization of Advanced Oxidation Processes Usi...

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International Conference on Wider-Uptake of Water Resource Recovery from Wastewater Treatment, ICWRR 2024

作者： Vicente, D.J. Pascacio, P. Salazar, F. Rodríguez-Chueca, J. Polo, M.I. Oller, I. CIMNE - International Centre for Numerical Methods in Engineering Madrid Spain Barcelona08034 Spain Department of Industrial Chemical & Environmental Engineering Escuela Técnica Superior de Ingenieros Industriales Universidad Politécnica de Madrid C/José Gutiérrez Abascal 2 Madrid28006 Spain CIEMAT- Plataforma Solar de Almería Ctra. De Senés S/N Tabernas Almería04200 Spain CIESOL Joint Centre of the University of Almería-CIEMAT Almería04120 Spain

ISBN: (纸本)9783031633522

The use of Machine Learning (ML) based methodologies is becoming an increasingly widespread technique for predicting the efficiency of Advanced Oxidation Processes (AOP) in wastewater treatment and regeneration. However, most studies focus predominantly on one or several organic compounds, without including contaminants of emerging concern. In addition, the outcomes are still far from being applicable to practical scenarios. To fill this gap, we are developing the DIGIT4WATER project, with the main objective of generating ML models to predict degradation levels of various pollutants, many of which are of particular importance concerning current legislation. To this end, a large and comprehensive database is being generated, which includes AOPs and photo-chemical processes based on UV-C or direct solar radiation. The project is aimed at building innovative digital tools for compliance with the new European regulation (EU 2020/741) governing water reuse in agriculture. This paper presents the current results, focusing on the proposed methodological framework, together with the next steps that will be carried out in the final phase of the project. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

关键词： Wastewater treatment

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Asymptotic Dynamics of High Dynamic Range Stratified Turbulence

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Physical Review Letters 2019年第19期122卷 194504-194504页

作者： G. D. Portwood S. M. de Bruyn Kops C. P. Caulfield Department of Mechanical and Industrial Engineering University of Massachusetts Amherst Massachusetts 01003 USA Continuum Models and Numerical Methods (XCP-4) X-Computational Physics Division Los Alamos National Laboratory Los Alamos New Mexico 87545 USA BP Institute University of Cambridge Cambridge CB3 0EZ United Kingdom Department of Applied Mathematics and Theoretical Physics University of Cambridge Cambridge CB3 0WA United Kingdom

Direct numerical simulations of homogeneous sheared and stably stratified turbulence are considered to probe the asymptotic high dynamic range regime suggested by Gargett et al. J. Fluid Mech. 144, 231 (1984) and Shih et al. J. Fluid Mech. 525, 193 (1999). We consider statistically stationary configurations of the flow that span three decades in dynamic range defined by the separation between the Ozmidov length scale LO=ε/N3 and the Kolmogorov length scale LK=(ν3/ε)1/4, up to Reb≡(LO/LK)4/3=ε/(νN2)∼O(1000), where ε is the mean turbulent kinetic energy dissipation rate, ν is the kinematic viscosity, and N is the buoyancy frequency. We isolate the effects of Reb, particularly on irreversible mixing, from the effects of other flow parameters of stratified and sheared turbulence. Specifically, we evaluate the influence of dynamic range independent of initial conditions. We present evidence that the flow approaches an asymptotic state for Reb⪆300, characterized both by an asymptotic partitioning between the potential and kinetic energies and by the approach of components of the dissipation rate to their expected values under the assumption of isotropy. As Reb increases above 100, there is a slight decrease in the turbulent flux coefficient Γ=χ/ε, where χ is the dissipation rate of buoyancy variance, but, for this flow, there is no evidence of the commonly suggested Γ∝Reb−1/2 dependence when 100≤Reb≤1000.

关键词： Shear flows Stratified geophysical flows Turbulence

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SAMPLE UNCERTAINTY IN FLOOD LEVEE DESIGN: BAYESIAN VERSUS NON‐BAYESIAN methods

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JAWRA Journal of the American Water Resources Association 1975年第3期11卷 425-436页

作者： Duckstein, L. Bogárdi, I. Szidarovszky, F. Davis, D.R. Department of Systems & Industrial Engineering and Hydrology Water Resources University of Arizona Tucson Arizona 85721 United States Water Resources Center Budapest Alkotmány u 29 Hungary Department of Numerical Methods Eötvös University Budapest Muzéum krt 6–8 Hungary

ABSTRACT: Bayesian and non‐Bayesian flood levee design methods that account for the uncertainty due to limited record length are compared using a case study. The first method, Bayesian decision theory (BDT), imbeds the uncertainty in the parameters of the yearly peak stage into a loss function. The optimum design of the flood levee, called Bayes design, corresponds to the minimum expected loss, called Bayes risk. The second method, induced safety algorithm (ISA), computes a margin of safety to be added to either an existing levee or a levee designed by classical benefit‐cost analysis. The design decision is shown to fluctuate as different record lengths are considered. For short record lengths, BDT, which takes small sample bias into account, appears to yield a more conservative design than ISA. On the other hand, ISA, which is simple to implement, seems to be preferable to BDT for longer record lengths. Copyright © 1975, Wiley Blackwell. All rights reserved

关键词： Bayesian decision theory Bayesian methods benefit‐risk analysis economic analysis factor of safety flood control hydraulic structures hydrology levees probability theory sample uncertainty water resources.

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PARALLEL AND DISTRIBUTED TLM COMPUTATION WITH SIGNAL-PROCESSING FOR ELECTROMAGNETIC-FIELD MODELING

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INTERNATIONAL JOURNAL OF numerical MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS 1995年第3-4期8卷 169-185页

作者： SO, PPM ESWARAPPA, C HOEFER, WJR NSERC/MPR Teltech Research Chair in RF Engineering Department of Electrical and Computer Engineering University of Victoria Victoria British Columbia V8W 3P6 Canada Poman So received his B.Sc. degree in computer science and physics from the University of Toronto Toronto Onatario Canada in 1985. He obtained his B.A. Sc. and M.A.Sc. degrees in electrical engineering (summa cum laude) from the University of Ottawa Ottawa Ontario Canada in 1987 and 1989 respectively. Mr So was a research engineer in the University of Ottawa from January 1989 to October 1991 his research interests included CAD techniques of microwave circuits and numerical methods for electromagnetic wave modelling. He specialized in the development of electromagnetic engineering CAD software and successfully implemented a number of electromagnetic wave simulators based on the two-dimensional and three-dimensional transmission-line matrix methods. From August 1990 to February 1991 he accompanied Professor W. J. R. Hoefer to Rome Italy and Sophia Antiopolas France. During that time he implemented a parallel version of the 3D-TLM simulator for the CM-2 Connection Machine using C-Star and X Windows Library. He is a research engineer and a Ph.D. student at the University of Victoria Victoria British Columbia Canada. He ported the 2D- and 3D-TLM simulators to DECmpp 1200 massively parallel computer using MPL C and C++. He also combined OSA90/hope a commercially available microwave CAD program with a 2D-TLM simulation module for geometry optimization using the Datapipe technique of OSA90/hope. Recently he has developed a distributed client-server computing technique for the TLM method this technique could accelerate the TLM simulation by more than an order of magnitude. Channabasappa Eswarappa received the M.Tech. degree in electrical engineering from the Indian Institute of Technology Kanpur India in 1983 and Ph. D. degree from the University of Ottawa Canada in 1990. He worked as an Assistant Executive Engineer and later as

This paper describes the implementation of transmission-line matrix (TLM) method algorithms on a massively parallel computer (DECmpp 12000), the technique of distributed computing in the UNIX environment, and the combination of TLM analysis with Prony's method as well as with autoregressive moving average (ARMA) digital signal processing for electromagnetic field modelling. By combining these advanced computation techniques, typical electromagnetic field modelling of microwave structures by TLM analysis can be accelerated by a few orders of magnitude.

关键词： Mathematical models

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Reservoir sedimentation under uncertainty: Analytic approach versus simulation

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Hydrological Sciences Bulletin 1977年第4期22卷 545-553页

作者： Bogardi, Istvan Duckstein, Lucien Szidarovszky, Ferenc Martin, Istvan Water Resources Centre Budapest H-1054 Alkotmany u. 29 Hungary Departments of Systems and Industrial Engineering and Hydrology and Water Resources University of Arizona Tucson AZ 85721 United States Department of Numerical Methods Eotvos University Budapest VIII H-1088 Muzeum krt. 6-8 Hungary School of Renewable Natural Resources University of Arizona Tucson AZ 85721 United States

Two methods are presented of estimating accumulated sediment yield stemming from erosion in a semiarid climate during a given time span, and the methods are compared from the viewpoint of the economic consequences evaluated within a Bayesian framework. The design of reservoirs requires the estimation of the random sediment volume Z accumulated over the lifetime of the project. An analytic and a simulation method are used to estimate the density function of Z and to calculate an economically optimal sediment storage space D*. A case study in Arizona, USA, is used to illustrate the methodology for the typical situation when only rainfall records are available. Both methods prove to be superior to the traditional procedure leaning on mean values. For the example considered, the two methods yield commensurate results. It appears that, in a semiarid basin, the effect of parameter uncertainty on both Z and D* may be considerably higher than that of natural uncertainty. © 1977 Taylor & Francis Group, LLC.

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Experimental investigation of surfactant-enhanced dissolution of residual NAPL in saturated soil

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GROUND WATER MONITORING AND REMEDIATION 1997年第4期17卷 89-98页

作者： Chevalier, LR Masten, SJ Wallace, RB Wiggert, DC Dr. Susan J. Mastenis an associate professor of environmental engineering in the Department of Civil and Environmental Engineering at Michigan State University (East Lansing MI 48824–1326 517/353-8539). She received a B.S. in biochemistry from Fairleigh Dickinson University an M.S.E. in environmental engineering from West Virginia University and a Ph.D. in environmental engineering from Harvard University. Prior to locating at MSU Dr. Masten conducted research at EAWAG-ETH Zurich Switzerland at the University of Melbourne Melbourne Australia and at the R.S. Kerr U.S. EPA Laboratory in Ada Oklahoma. Her research is focused on using chemical oxidation processes to remediate ground water and soils that are contaminated with organic chemicals. She also has extensive experience in the area of analytical chemistry. Professor David C. Wiggert'scurrent research interests in the area of environmental fluid mechanics are associated with ground water remediation. He is involved in experimental testing field studies and modeling of bioremediation of contaminants in ground water and in the application of innovative techniques to enhance the delivery of chemicals microbes and nutrients into contaminated soils to enhance in situ remediation. Recently completed projects dealt with the formation and performance of frozen containment barriers and the natural remediation properties of an industrial ground water recharge pond. Past research includes analysis of ground water flow in relation to water quality improvement and hydrologic and water quality studies of small watersheds. He is also actively researching fluid transients associated with free-surface flows and with pipeline systems specific topics include fluid-structure interaction and uncertainty analysis. Professor Roger B. Wallace'sresearch involves the mechanics of fluids in porous media. Current research focuses on contaminant transport and remediation in ground water systems including the role of nonaqueous phase liquids such as gasoline. This includes ex

Nonaqueous phase liquid (NAPL) is a longterm source of ground water contamination as the pollutant slowly partitions into the air and water phases. The objective of this work was to study the efficacy of aqueous surfactant solution to enhance the dissolution of a residual NAPL below the capillary fringe, hence reducing the time needed for aquifer restoration. An analytical technique was developed to measure the concentration of NAPL in a nonionic surfactant. Soil column experiments simulated conditions in the saturated soil where a NAPL may become trapped as a discontinuous immobile phase. Experimental results indicate that dissolution was a rate-limited process, approaching equilibrium concentrations after 24 hours. The relative permeability of the aqueous phase initially decreased as surfactant was injected, but increased over time as the saturation of residual NAPL was reduced through mass transfer into the surfactant-enhanced aqueous phase. These findings suggest that enhancing the aqueous phase with a nonionic surfactant may significantly enhance the in situ recovery or residual NAPL.

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Interactive analysis of propagation in optical fibers

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Computer Applications in engineering Education 1993年第3期1卷 197-197页

作者： Aicklen, G.H. Tamil, L.S. Erik Jonsson School of Engineering and Computer Science and Center for Applied Optics The University of Texas at Dallas Richardson 75080 Prior to returning to graduate study in 1987 Mr. Aicklen had industrial experience with the Defense Systems and Electronics Group at Texas Instruments in Dallas. In 1985 he left Texas Instruments to pursue a private venture. In 1987 he joined the staff of The University of Texas at Dallas as a research associate in the Erik Jonsson School of Engineering and Computer Science. Mr. Aicklen's research interests include fiber optics nonlinear guided wave optics integrated optical devices and numerical methods in optics. Dr. Tamil is a member of Sigma Xi Optical Society of America Electromagnetics Academy and is a elected member of Commission B and D of the International Union of Radio Science.

We have developed a set of computer codes that compute the propagation constants and field patterns for the propagating modes of cylindrical optical fibers. From a simple set of finite difference equations, solutions of the scalar Helmholtz wave-equation may be computed across a range of normalized frequencies to generate curves describing the dispersion characteristics of the fiber. Accurate cutoff frequencies for any mode can also be computed. We designed the computer codes around α-index profiles since these profiles have been extensively covered in the literature, but our system also supports arbitrary profiles within the limits of the “small index gradient” and “weakly guiding” approximations. The computer codes are accurate and fast. They may be used interactively to explore dispersion in optical fibers and the effects of finite cladding width on dispersion.

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