Sharif Digital Repository

In this investigation, cellular structure of a weakly unstable detonation wave in H2/O2/Ar mixture is studied. The detonation is simulated using 2D reactive Euler equations and one step Arrhenius type reaction model developed by Mr. Barkhordari. The numerical technique is the high order Piecewise Parabolic Method on the basis of Godonov method. The numerical fluxes are computed based on a high-order extension of the Godunov's method; the piecewise parabolic method (PPM). The initial cell formation processes and different machanisms involved in cell size changes are studied. This study shows that the form of initial perturbation used to intrigate the instability of detonation is not important... 

Asphaltine particle precipitation may lead to serious problems in petroleum industry; including wellbore transmissibility reduction. One of the proposed remedial methods is to make a use of the microorganisms which are able to consume the heavy hydrocarbon chains.
Hydrophobicity of a cell surface is one of the parameters which greatly affect the microorganism adhesion to water insoluble hydrocarbons, in which results a higher hydrocarbon biodegradation. Consequently as the hydrophobicity of a cell surface increases; the microorganism tendency to bond with the hydrocarbon molecule enhances. The presence of a surface active agent, as an instance a chemical surfactant, will affect the... 

Radio-Frequency Identification (RFID) in many applications, namely supply chain management; access management; tracking commodity, people, and animals; and storage of medical information, to name but a few, be remembered as the most effective method of gathering information. Accordingly, accurate modeling and optimizing of this technology with attention to its daily development in varied applications, has a significant role. In this regard, some issues – that is – reader location, the number of tags that are controlled by a reader, and data communications of readers with central server, to name but a handful, are challenging and there are attemps to optimize the network in terms of cost,... 

Experimental studies of regular cell structure of a weak detonation wave in a gaseous mixture of hydrogen and oxygen diluted with argon have shown that for a constant initial thermodynamic condition, the final cell size differs by repeating the tests. The question is that if these different final cell sizes for a constant initial condition are because of test errors, or the experiments would lead to a domain of solution in the form of different final cell sizes? Therefore, the aim of this study is to investigate, numerically, the evolution process and domain of variation of cellular structure of a weak detonation, and their dependency to unstable wavelengths obtained from linear instability...