Influence Of Non-ideal Effects Research Articles

Modeling and Simulation of a Photosynthetic Solar Cell

Abstract. Solar energy’s potential as a clean, abundant, and economical energy source can be effectively exploited if it is converted to electricity. Photosynthetic solar cells (PSCs) convert sunlight to electricity by using plant cells via photosynthesis and respiration. These processes can be interrupted to provide a path of lesser resistance for the transfer of protons and electrons in a proton exchange membrane fuel cell system. PSCs require no organic fuel, no active feeding system, and produce carbon-neutral power both day and night. In this article, the mechanisms of photosynthesis that generate electrons and protons in the anode chamber are described and modeled. In addition, the concentrations of various species in the anode and cathode chambers, including plant cells, sugars, reducing agents, and catalysts, are modeled as a function of time and used to simulate the electric potential across the fuel cell. The resulting flow of electrons through the external circuit is described. The influence of non-ideal effects is described and modeled, such as the resistance to the motion of protons, reactants, and products through the electrolyte, which contributes to a voltage drop across the cell. The activation energy required for the chemical reactions also contributes to voltage drop. These dynamics are modeled using differential equations for each species. This model can be used to predict the dynamics of a PSC system under various conditions. Keywords: Cell power, Cell voltage, Microbial fuel cell, Modeling, Photosynthetic solar cell, Solar energy.

Modeling Gas Permeation by Linking Nonideal Effects

Conventional models for simulating gas-separation processes often neglect nonideal effects such as concentration polarization, the Joule-Thomson Effect, pressure losses, and real gas behavior. This study presents a comprehensive model which accounts for such nonideal effects and can be applied in commercial process simulations. A model of a hollow-fiber gas permeation module was programmed in Aspen Custom Modeler. In general, pure gas measurements at a single feed pressure were sufficient to predict the mixed gas behavior of the module. The influence of nonideal effects on the module efficiency was investigated in two case studies addressing the separation of CO2/propane and CO2/methane gas mixtures. For the first case, the curves of CO2 concentration versus module length were congruent for both ideal and realistic scenarios. The divergence of the curves in the second case was attributed to the influence of cummulating nonideal effects. The simulations are in agreement with the new data obtained for these...

Simulated moving bed chromatography under linear conditions

The authors review their recent contributions to the theory of Simulated Moving Bed (SMB) chromatography. SMB is an implementation of preparative chromatography which is attracting much interest in the pharmaceutical industry, especially (but not only) for the purification of enantiomers. This process is more complex than those conventionally used for preparative applications. Its operation under linear conditions is illustrated using the numerical solutions derived from different simple models (ideal, equilibrium-dispersive). The influence of nonideal effects (e.g., dispersion and mass transfer resistances), of section subdivision into several columns are discussed. The importance of the differences between the flow rates in the different sections of the SMB is also illustrated. Experimental results are well explained by theoretical considerations.

Compressible Convection with Ionization. I. Stability, Flow Asymmetries, and Energy Transport

The influence of nonideal effects associated with ionization upon the dynamics and thermodynamics of compressible convection is studied. Linear and finite-amplitude analyses and fully nonlinear two-dimensional simulations of a plane-parallel layer of single-atomic-level hydrogen fluid are undertaken. Ionization significantly influences both the global transport properties and the local dynamics of convective flows by modifying the particle number density, specific heat, and internal energy content of the fluid. Strong temperature fluctuations and corresponding buoyancy forces develop locally in the fluid wherever rapid changes in ionization state occur. These can result in narrow regions of intense vertical flow

Ion temperature effect on the propagation of ion acoustic solitary waves in a relativistic magnetoplasma

Using the reductive perturbation technique the author has derived the Korteweg-de Vries (KdV) equation for ion acoustic waves, in the presence of weak relativistic effects and warm ions, in a magnetized plasma. The influence of nonideal effects on the amplitude and width of the ion acoustic solitary waves is also discussed. The results are depicted in the figures. It is shown that the simultaneous presence of ion streaming and magnetic field stops the tendency of soliton breaking.