A structured mathematical model of anaerobic conversion of complex organic materials in non-ideally cyclic-batch reactors for biogas production has been developed. The  model is based on multiple-reaction stoichiometry (enzymatic hydrolysis, acidogenesis, acetogenesis and methanogenesis), microbial growth kinetics, conventional material balances in the liquid and gas phases for a cyclic-bat...

A model for the theoretical description of KIRKENDALL voiding is presented based on vacancy diffusion and plastic deformation of spherical voids. We start with a phenomenological explanation of the KIRKENDALL phenomenon and discuss its consequences on microelectronic reliability. After that a constitutive model for void growth is introduced, which, for instances, can be used in order to predict...

A finite element (FE) analysis of a CT25 specimen has been achieved for three configurations of a welded structure : monometallic (base metal), bimetallic (base metal and weld metal) and trimetallic (BM+WM+HAZ). Using the RICE-TRACEY model, a void growth parameter R& has been computed for each case. The evolution of this parameter indicates clearly that the bimetallic specimen is the most h d w...

Laser shock experiments conducted at an energy density of 61 MJ/m revealed void initiation and growth at stress application times of approximately 10 ns. It is shown that void growth cannot be accomplished by vacancy diffusion under these conditions, even taking into account shock heating. An alternative, dislocation-emission-based mechanism, is proposed for void growth. The shear stresses are ...

The fatigue behavior of polyether ether ketone (PEEK) thermoplastic was investigated under uniaxial strain-controlled cyclic loading condition with various mean strains (Rε 1⁄4 0, 0.2, and 0.25). The mean stress responses of PEEK from all mean strain fatigue tests were found to be fully-relaxed. As a result, minimum mean strain effect on fatigue behavior of PEEK was observed. Fractography analy...

Shock wave induced spall fracture is a complex multiscale phenomenon, and it is a challenge to build a constitutive and computational model that can capture the essential features of the spall fracture. In this work, we present a computational micro-mechanics model to simulate spall fracture by using part of the multiscale micro-mechanics theory proposed the Wright and Ramesh (Wright and Ramesh...

A method based on Electrical Capacitance Tomography (ECT) and an improved Least Squares Support Vector Machine (LS-SVM) is proposed for void fraction measurement of oil-gas two-phase flow. In the modeling stage, to solve the two problems in LS-SVM, pruning skills are employed to make LS-SVM sparse and robust; then the Real-Coded Genetic Algorithm is introduced to solve the difficult problem...