Output-transition optimization through a multi-objective least square procedure

The paper deals with the application of the so-called T-type finite elements [1] to the calculation of the exterior acoustic problems in two dimensions. The method is based on the use of asuitably truncated T-complete set of Trefftz functions over individual subdomains linked by means ofa least square procedure. The vertex singularities and the Sommerfeld radiation condition are readilyincorporated in the trial functions. In order to show the performance of the approach two examples ofcomputations for infinite cylinders (of circular and square cross section) are presented and comparedwith those obtained by means of h-adaptive FE method [2].

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Modelling of Cyclic Plasticity and Viscoplasticity of Directionally Solified DZ125 Superalloy: Part I: Estimating the Parameters of Chaboche Constitutive Equations

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.295-297.854 ◽

2011 ◽

Vol 295-297 ◽

pp. 854-858

Author(s):

Jie Qiong Li ◽

Li Jun Wang

Keyword(s):

Constitutive Model ◽

Test Data ◽

Creep Test ◽

Constitutive Equations ◽

Least Square ◽

Cyclic Plasticity ◽

Initial Material ◽

Material Parameters ◽

Cyclic Relaxation ◽

Least Square Procedure

Cyclic plasticity and viscoplasticity of directionally solified superalloy, DZ125, have been described using the Chaboche uniﬁed constitutive model. A set of initial material parameters has been determined utilizing the monotonic, cyclic, relaxation and creep test data of DZ125 at 980°C, while an optimum set of material parameters has been obtained by means of least-square procedure.

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Adsorption of amyloglucosidase from Aspergillus niger NRRL 3122 using ion exchange resin

Brazilian Archives of Biology and Technology ◽

10.1590/s1516-89132008000500019 ◽

2008 ◽

Vol 51 (5) ◽

pp. 1015-1024 ◽

Cited By ~ 3

Author(s):

Ana Paula Manera ◽

Eliana Setsuko Kamimura ◽

Luciana Machado Brites ◽

Susana Juliano Kalil

Keyword(s):

Aspergillus Niger ◽

Partition Coefficient ◽

Partition Coefficients ◽

Deae Cellulose ◽

Ion Exchange Resin ◽

Least Square ◽

Optimum Conditions ◽

Equilibrium Partition ◽

Equilibrium Partition Coefficient ◽

Least Square Procedure

Amyloglucosidase enzyme was produced by Aspergillus niger NRRL 3122 from solid-state fermentation, using deffated rice bran as substrate. The effects of process parameters (pH, temperature) in the equilibrium partition coefficient for the system amyloglucosidase - resin DEAE-cellulose were investigated, aiming at obtaining the optimum conditions for a subsequent purification process. The highest partition coefficients were obtained using 0.025M Tris-HCl buffer, pH 8.0 and 25ºC. The conditions that supplied the highest partition coefficient were specified, the isotherm that better described the amyloglucosidase process of adsorption obtained. It was observed that the adsorption could be well described by Langmuir equation and the values of Qm and Kd estimated at 133.0 U mL-1 and 15.4 U mL-1, respectively. From the adjustment of the kinetic curves using the fourth-order Runge-Kutta algorithm, the adsorption (k1) and desorption (k2) constants were obtained through optimization by the least square procedure, and the values calculated were 2.4x10-3 mL U-1 min-1 for k1 and 0.037 min-1 for k2 .

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Finite Element Analysis and Multi-Objective Optimization of the Precision Horizontal Machining Center Bed

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.889-890.130 ◽

2014 ◽

Vol 889-890 ◽

pp. 130-134

Author(s):

Xue Yan Li ◽

Wen Tie Niu ◽

Jun Qiang Wang ◽

Ling Jun Xue

Keyword(s):

Response Surface ◽

Response Surface Model ◽

Least Square ◽

Surface Model ◽

Multi Objective Optimization ◽

Element Analysis ◽

Maximum Deformation ◽

Multi Objective ◽

Machining Center ◽

Sample Points

In order to improve dynamic and static performance of the precision horizontal machining center, the method of multi-objective optimization based on the response surface model was applied for optimizing design of the bed structure. The design variables were the layout parameters of the rib plates. Sample points were obtained by the Box-Behnken design experiment, and responses of sample points were analyzed by SAMCEF. The maximum deformation of guide rails and the low-order natural frequency were extracted to fit the response surface model by least square method. The layout parameters of the rib plates were optimized through the application of multi-objective genetic algorithms. Then, relationship between the lightening holes and the performance were analyzed to determine the suitable diameter. The results verify the validity of the optimization method, and the paper provides methodological guidance for optimization of machine tool structural parts.

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