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Metallic Structures (metallic + structure)
Selected AbstractsMaterials and Corrosion 9/2010MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 9 2010Article first published online: 2 SEP 2010 Cover: Metallic structure of X1NiCrMoCu32-28-7 (UNS N08031, alloy 31, 1.4562) welded with SG-NiCr23Mo16 (FM 59, 2.4607) after 4 weeks in the vapor phase of nitrating acid (mixture of 66 % HNO3, 34 % H2SO4) at 55 °C. No further treatment of the surface was made. Corrosion behavior was investigated at BAM, the Federal Institute for Materials Research and Testing, in order to extend the BAM-List, where the suitability of materials for transport tanks carrying Dangerous Goods is evaluated. More detailed information can be found in: R. Bäßler. M. Weltschev, H. Alves, M. Langer, Corrosion Resistance of Alloy 31 and 59 in Highly Corrosive Dangerous Goods, Proceedings NACE International Corrosion Conference 2010 San Antonio, paper 10340. [source] Materials and Corrosion 8/2010MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 8 2010Article first published online: 2 AUG 2010 Cover: Metallic structure of X1NiCrMoCu32-28-7 (UNS N08031, alloy 31, 1.4562) welded with SG-NiCr23Mo16 (FM 59, 2.4607) after 4 weeks in the vapor phase of nitrating acid (mixture of 66 % HNO3, 34 % H2SO4) at 55 °C. No further treatment of the surface was made. Corrosion behavior was investigated at BAM, the Federal Institute for Materials Research and Testing, in order to extend the BAM-List, where the suitability of materials for transport tanks carrying Dangerous Goods is evaluated. More detailed information can be found in: R. Bäßler. M. Weltschev, H. Alves, M. Langer, Corrosion Resistance of Alloy 31 and 59 in Highly Corrosive Dangerous Goods, Proceedings NACE International Corrosion Conference 2010 San Antonio, paper 10340. [source] Materials and Corrosion 7/2010MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 7 2010Article first published online: 19 JUL 2010 Cover: Metallic structure of X1NiCrMoCu32?28?7 (UNS N08031, alloy 31, 1.4562) welded with SG-NiCr23Mo16 (FM 59, 2.4607) after 4 weeks in the vapor phase of nitrating acid (mixture of 66 % HNO3, 34 % H2SO4) at 55 °C. No further treatment of the surface was made. Corrosion behavior was investigated at BAM, the Federal Institute for Materials Research and Testing, in order to extend the BAM-List, where the suitability of materials for transport tanks carrying Dangerous Goods is evaluated. More detailed information can be found in: R. Bäßler. M. Weltschev, H. Alves, M. Langer, Corrosion Resistance of Alloy 31 and 59 in Highly Corrosive Dangerous Goods, Proceedings NACE International Corrosion Conference 2010 San Antonio, paper 10340. [source] Mitigation of the produced voltages in AC overhead power-lines/pipelines parallelism during power frequency and lightning conditionsEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 4 2005I. A. Metwally Abstract This paper presents a theoretical simulation for a pipeline running in parallel to AC overhead power lines using the ,CONCEPT II' package. This package is based on the method of moment combined with a transmission-line model. A 1,km long, 132,kV, three-phase, double-circuit transmission line, and a 2,km long, 40,cm diameter, 1,m high above-ground pipeline are modelled. Extra shielding wires (ESW) under the phase conductors are investigated. Produced voltages in the pipeline are computed under steady-state power frequency (50,Hz) as well as under direct and indirect lightning strikes to the power line. Different current waveforms are simulated to cover the whole range of those of the anticipated lightning. Under lightning strikes, the voltages across line insulators are computed, too. The results reveal that the ESW give many advantages; namely, (1) reducing the power-frequency electric and magnetic fields at the ground level to meet the regularity limits, (2) improving the shielding effectiveness during lightning strikes by reducing the insulator voltages, (3) mitigating the induced voltages in any metallic structure near the power lines, e.g., pipelines, and (4) using them as optical ground wires for telecommunication purposes, where the probability of lightning strikes to such ESW is much lower than that for the normally used grounding wire(s) at the tower top. Copyright © 2005 John Wiley & Sons, Ltd. [source] Numerical simulation grounding system buried within horizontal multilayer earth in frequency domainINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 1 2007Zhong-Xin Li Abstract A novel mathematical model for accurately calculating the currents flowing along the conductors of grounding system below high voltage a.c. substations and nearby floating metallic structure buried in horizontal multilayer earth model has been developed in this paper. Not only the mutual conductive and capacitive coupling influences of leakage currents, but also mutual inductive coupling influence of network currents flowing along the conductors of grounding system and nearby floating metallic structure in the horizontal multilayer earth model have been considered in this model, and only propagation effect of electromagnetic wave within limited area of the substation has been neglected. The quasi-static complex image method and closed form of Green's function are introduced into this model to accelerate the calculation. The model is then implemented in a computer program, which can be used to calculate currents distribution along the conductors of any configuration of grounding system, and with or without floating metallic structure under some hundreds of kHz frequency harmonic wave. Copyright © 2006 John Wiley & Sons, Ltd. [source] XAFS analysis of corroded metal surfaces with molten salts by conversion-electron-yield methodJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2001Etsuya Yanase We have measured XAFS spectra of metal surfaces corroded with melting salt (NaCl, KCl, and Na2SO4). Steel samples used were S45C, SCM435, SUS310S, and SUS304. We measured the Fe K-edge XAFS spectra for all samples and the Ni K-edge for SUS310S and SUS304 samples before and after the corrosion. The XANES spectra of samples before the corrosion show metallic structure because surface oxide thickness is thinner than probing depth with a conversion yield XAFS method. Each result of these XAFS spectra gives good agreements with the FEFF calculation in the assumption of bcc and/or fcc structure. The Fe K-edge spectra of steel samples except SUS310S after corroded treatment show existence bonding between Fe and another light element although the spectra of SUS310S samples before and after corroded treatment are much the same. Keywords: metal, molten salts, corrosion. [source] Piezoelectric wafer active sensors for in situ ultrasonic-guided wave SHMFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 8 2008L. YU ABSTRACT In situ structural health monitoring aims to perform on-demand interrogation of the structure to determine the presence of service-induced damage and defects using non-destructive evaluation ultrasonic wave methods. Recently emerged piezoelectric wafer active sensors (PWAS) have the potential to significantly improve damage detection and health monitoring. PWAS are low-profile transducers that can be permanently attached onto the structure or inserted in between composite laminates, and can perform structural damage detection in thin-wall structures using guided wave methods (Lamb, Rayleigh, SH, etc.). This paper describes the analytical and experimental work of using PWAS-guided waves for in situ structural damage detection on thin-wall structures. We begin with reviewing the guided wave theory in plate structures and PWAS principles. The mechanisms of Lamb wave excitation and detection using PWAS is presented. Subsequently, we address in turn the use of PWAS to generate Lamb waves for damage (cracks and corrosion) detection in metallic structures. Pulse-echo, pitch-catch, phased array and time reversal methods are illustrated demonstrating that PWAS Lamb-waves techniques are suitable for damage detection and structural health monitoring. The last part of the paper treats analytically and experimentally PWAS excitation and tuning in composite materials. The research results presented in this paper show that in situ SHM methodologies using PWAS transducers hold the promise for more efficient, effective and timely damage detection in thin-wall structures. [source] Tailored Plasmonic Gratings for Enhanced Fluorescence Detection and Microscopic ImagingADVANCED FUNCTIONAL MATERIALS, Issue 4 2010Xiaoqiang Cui Abstract The ability to precisely control the pattern of metallic structures at the micro- and nanoscale for surface plasmon coupling has been demonstrated to be essential for signal enhancement in fields such as fluorescence and surface-enhanced Raman scattering. In the present study, a series of silver coated gratings with tailored duty ratio and depth and a periodical pitch of 400,nm are designed and implemented. The influence of the grating profile on plasmonic properties and the corresponding enhancement factor are investigated by angular scanning measurement of reflectivity and fluorescence intensity and by finite difference time domain simulation. The application of the substrate in the enhanced fluorescence imaging detection of labeled protein is also investigated. This substrate has a wide range of potential applications in areas including biodiagnostics, imaging, sensing, and photovoltaic cells. [source] Finite elements modelling of the long-term behaviour of a full-scale flexible pavement with the shakedown theoryINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 1 2009Cyrille Chazallon Abstract Rutting, due to permanent deformations of unbound materials, is one of the principal damage modes of low-traffic pavements. Flexible pavement design methods remain empirical; they do not take into account the inelastic behaviour of pavement materials and do not predict the rutting under cyclic loading. A simplified method, based on the concept of the shakedown theory developed by Zarka for metallic structures under cyclic loadings, has been used to estimate the permanent deformations of unbound granular materials subjected to traffic loading. Based on repeated load triaxial tests, a general procedure has been developed for the determination of the material parameters of the constitutive model. Finally, the results of a finite elements modelling of the long-term behaviour of a flexible pavement with the simplified method are presented and compared with the results of a full-scale flexible pavement experiment performed by Laboratoire Central des Ponts et Chaussées. Finally, the calculation of the rut depth evolution with time is carried out. Copyright © 2008 John Wiley & Sons, Ltd. [source] A numerical model for flexible pavements rut depth evolution with timeINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 1 2007Fatima Allou Abstract A simplified method has been developed for the finite elements modelling of flexible pavements rut depth evolution with time. This method is based on the shakedown theory established by Zarka for metallic structures. The yield surface of Drucker-Prager and the plastic potential of Von Mises have been used. The simplified method determines straightforwardly the purely elastic state or the elastic shakedown state or the plastic shakedown state. The calibration of the simplified method with two unbound granular materials for roads under repeated loads triaxial tests, is explained. Then, a finite elements modelling of a flexible pavement has been carried out. Calculations of 2D and 3D have been performed and rut depth evolutions with time are shown, which underline the capabilities of the model to take into account the accumulation of plastic strains along the loading cycles. Copyright © 2006 John Wiley & Sons, Ltd. [source] On the design of energy,momentum integration schemes for arbitrary continuum formulations.INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 15 2004Applications to classical, chaotic motion of shells Abstract The construction of energy,momentum methods depends heavily on three kinds of non-linearities: (1) the geometric (non-linearity of the strain,displacement relation), (2) the material (non-linearity of the elastic constitutive law), and (3) the one exhibited in displacement-dependent loading. In previous works, the authors have developed a general method which is valid for any kind of geometric non-linearity. In this paper, we extend the method and combine it with a treatment of material non-linearity as well as that exhibited in force terms. In addition, the dynamical formulation is presented in a general finite element framework where enhanced strains are incorporated as well. The non-linearity of the constitutive law necessitates a new treatment of the enhanced strains in order to retain the energy conservation property. Use is made of the logarithmic strain tensor which allows for a highly non-linear material law, while preserving the advantage of considering non-linear vibrations of classical metallic structures. Various examples and applications to classical and non-classical vibrations and non-linear motion of shells are presented, including (1) chaotic motion of arches, cylinders and caps using a linear constitutive law and (2) large overall motion and non-linear vibration of shells using non-linear constitutive law. Copyright © 2004 John Wiley & Sons, Ltd. [source] A three-dimensional mesh refinement algorithm with low boundary reflections for the finite-difference time-domain simulation of metallic structuresINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 3 2010W. H. P. Pernice Abstract We present a method for including areas of high grid density into a general grid for the finite-difference time-domain method in three dimensions. Reflections occurring at the boundaries separating domains of different grid size are reduced significantly by introducing appropriate interpolation methods for missing boundary points. Several levels of refinement can be included into one calculation using a hierarchical refinement architecture. The algorithm is implemented with an auxiliary differential equation technique that allows for the simulation of metallic structures. We illustrate the performance of the algorithm through the simulation of metal nano-particles included in a coarser grid and by investigating gold optical antennas. Copyright © 2009 John Wiley & Sons, Ltd. [source] Electrosensory avoidance of metal obstacles by the paddlefishJOURNAL OF FISH BIOLOGY, Issue 2 2000C. Gurgens Paddlefish Polyodon spathula detected and avoided obstacles with an exposed metallic surface but not plastic objects. An aluminium obstacle was avoided from significantly greater minimum approach distances than were any of the other obstacles. No significant difference was detected between the plastic and plastic-covered aluminium obstacles, while control values were significantly less than for all obstacle types. Avoidance distances measured at different water conductivities were not significantly different. Fish collided frequently with the plastic and plastic-covered aluminium obstacles, and with the control site, suggesting that these obstacles were not detected by the electrosensory apparatus. The aluminium obstacle was avoided successfully in all test runs. The unambiguous avoidance behaviour elicited by the aluminium obstacle suggests that large metallic structures, such as locks and dams, have the potential to interfere with paddlefish migrations. ©2000 The Fisheries Society of the British Isles [source] | |||||||||||||