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Lipoproteins are biochemical compounds containing both proteins and lipids. These particles carry chemicals like cholesterol and triglycerides that are not soluble in aqueous solutions. This paper presents modeling of lipoprotein system using coarse grain molecular dynamics technique and stability analysis of this system in a water solution like blood. A high density lipoprotein (HDL) that consists of two annular monomers is modeled. Also there are lipid bilayers located in center of the rings, so the whole HDL and lipid bilayers are called lipoprotein system. First, all atom model is provided and then coarse-grain model is obtained using MARTINI technique. Modeling of the system in all atom and coarse-grain is performed by VMD and simulation is executed by NAMD. System is simulated for 400ns with time step of 20fs in NPT ensemble. System temperature assumed similar to normal human body temperature. Finally the structure shape and stability of system were considered and results were analyzed.

The major source of energy is fossil fuels, known as hydrocarbon containing C and H as the main elements. The heat generated from combustion of these fuels is used in power generation cycles to generate electricity. Main products of a hydrocarbon combustion reaction are water and carbon dioxide, but due to some reasons such as excessive temperature and inappropriate air-fuel mixing, always some pollutants are formed. One of the major concerns of recent years are NOx pollutants, which is mostly generated in the high temperature combustions. According to the geographical and economic issues, most countries are using coal as fuel and many researches have been conducted about pollutant formation and temperature distribution in coal fired boilers (H. Y. Park, et al,. J. R. Fan, et al, and many others), but in Middle Eastern countries, the dominant fuel for the power generation cycles is natural gas. In this paper, pollutant formation and temperature distribution is numerically studied in a power generation boiler using natural gas as fuel. NOx formation mechanisms are introduced and discussed about the main source of NOx pollutants in this boiler. The natural gas burners are appropriate for non-premixed flame, so the goal of this study is to achieve the desired temperature distribution and minimize NOx pollutants through the variation of inlet angle of fuel and air in the burner. A case study is presented for boiler with 156MW power, equipped with natural gas burners. Numerical simulation is applied for the mentioned system and optimization consideration on pollutant is discussed.

Many theories and mathematical simulations have been proposed concerning urine concentrating mechanism (UCM). The WKM and region approach are the two most valuable methods for compensating the effect of tubule’s architecture in renal medulla. They both have tried to simulate tubule’s confinement within a particular region mathematically in one spatial dimension. In this study, continuity, momentum and species transport equations along with standard expressions for transtubular solutes and water transports on tubule’s membrane were solved numerically in three spatial dimensions which practically is the main significance of our novel approach. Model structure has been chosen as simple as possible to minimize the effect of other factors in tubule’s solute and water exchange. It has been tried to simulate the preferential interaction between tubules by introducing different diffusion coefficients for solutes in the intermediate media in order that changing this physical parameter directly could influence tubule’s confinement with respect to each other. The results have been discussed in detail and then the effect of solute’s diffusivity on UCM has been investigated subsequently. In overall, it has been found out that this simulation can validate the integrity of our proposed approach for further investigation in this field.