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FE Solution (fe + solution)

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Engineering100%

Selected Abstracts

Characteristic improvement of metal-contaminated sludge using mineralization technology

ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2010
Shao-Hua Hu
Abstract This study focuses on improving crystalline characteristics of metal-contaminated sludge. The mineralization behavior of Cu/Al or Cu/Fe coexisting in solution is surveyed, and the characteristics of residue and suspension settling are discussed in the context of water content of residue and settling/specific filtration resistance of suspensions. Experimental data show that the hydrate of Cu4SO4(OH)6 forms during mineralization of copper sulfate solution when hydroxide ion concentration, reaction time, and temperature are not controlled appropriately. Mineral characteristics of the residue are usually poor when the Cu4SO4(OH)6 forms in Cu/Al or Cu/Fe solution. However, Cu4SO4(OH)6 can be further transformed into CuO with wet oxidation or ferrite method, respectively (i.e., mineralization treatment). Water reduction of the residue is from 96.8% to 72.8% in the Cu/Al case or 95.6% to 66.6% in the Cu/Fe case, and the mineralized residue volume is only 1/10 of the hydrate sediment. This is particularly beneficial for sludge disposal. © 2009 American Institute of Chemical Engineers Environ Prog, 2010 [source]

The one-level functional equation of multi-rate loss systems

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 2 2003
Harro L. Hartmann
Motivated by the discrete multi-rate Kaufmann,Roberts recurrence relations, we derive a functional equation (FE), which covers nonintegral states. This FE implies a unique effective step parameter d, which defines an equivalent one-level recurrence depth, or bit-rate, at each state under progress. This state-dependent depth results from the equality requirement of the multi-rate and the one-level model in the moment-generating function transform domain. By this method it is possible to model d by a few moments of the original multi-rate statistic. In this case we obtain an explicit FE solution covering the entire (global) state space. Next we verify that the resulting state probability density incorporates iteratively enumerated discrete state probabilities, including the state-dependent depth. With a system capacity C the iterations then need time complexities between O(C) and O(C2). In contrast to this each FE state, is performed at a time complexity O(1). By the efficient coverage of the whole state space, fast optimizations of multi-rate networks and multi-resource systems can be improved. Copyright © 2003 AEI. [source]

Further comments on the performances of finite element simulators for the solution of electromagnetic problems involving metamaterials

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2006
Gaia Cevini
Abstract In this paper, we analyze the performances of three-dimensional finite element (FE) simulators in handling electromagnetic scattering problems involving metamaterials. It has already been proved that the performances of the FE method are worse than usual, when metamaterials are considered. In this work, we extend our previous analysis by providing some additional results on the precision of the FE solution and on the performances of the iterative and direct solvers typically used with FE simulators. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48:2524,2529, 2006; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.22008 [source]

Inverse design of directional solidification processes in the presence of a strong external magnetic field

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 11 2001
Rajiv Sampath
Abstract A computational method for the design of directional alloy solidification processes is addressed such that a desired growth velocity ,f under stable growth conditions is achieved. An externally imposed magnetic field is introduced to facilitate the design process and to reduce macrosegregation by the damping of melt flow. The design problem is posed as a functional optimization problem. The unknowns of the design problem are the thermal boundary conditions. The cost functional is taken as the square of the L2 norm of an expression representing the deviation of the freezing interface thermal conditions from the conditions corresponding to local thermodynamic equilibrium. The adjoint method for the inverse design of continuum processes is adopted in this work. A continuum adjoint system is derived to calculate the adjoint temperature, concentration, velocity and electric potential fields such that the gradient of the L2 cost functional can be expressed analytically. The cost functional minimization process is realized by the conjugate gradient method via the FE solutions of the continuum direct, sensitivity and adjoint problems. The developed formulation is demonstrated with an example of designing the boundary thermal fluxes for the directional growth of a germanium melt with dopant impurities in the presence of an externally applied magnetic field. The design is shown to achieve a stable interface growth at a prescribed desired growth rate. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Untersuchung verschiedener Bodenmodelle zur Berechnung von Fundamentplatten im Rahmen von FEM-Lösungen

BAUTECHNIK, Issue 5 2004
Christian Barth Prof. Dr.-Ing.
#Die wirklichkeitsnahe Abbildung von Bauwerk-Boden-Wechselwirkungen in Finite-Elemente-Programmen ist ungeachtet des gegenwärtig hohen Entwicklungsstands der verfügbaren Software eine nicht zu unterschätzende Aufgabe. Einerseits erfordert die richtige Einbindung des Bodenmodells in die FE-Berechnung viele Überlegungen und Kenntnisse, andererseits sind die in der Software implementierten Bodenmodelle aber für den Anwender nicht immer in ihrer gesamten Komplexität durchschaubar. Anhand alltäglicher Aufgabenstellungen werden vier verschiedene häufig verwendete und in FEM-Lösungen implementierte Bodenmodelle unterschiedlicher Softwarehersteller untersucht. Die erzielten Ergebnisse werden gegenübergestellt, und der Versuch einer Bewertung wird vorgenommen. Investigation of different models for the analysis of foundation slabs with reference to FEM solutions. The realistic interaction between a foundation slab and the soil in FE-programs is a formidable and complex task, despite the availability of sophisticated software solutions. On the one hand the incorporation of the slab-soil behaviour into conventional software programs requires considerable experience and thought and, on the other hand, existing software programs are often difficult to understand because of their complexity. Using common design examples four different models, which arc frequently used in FE solutions, are applied in this study. The results are compared and critically examined. [source]