H2-selective mixed matrix membranes modeling using ANFIS,PSO-ANFIS,GA-ANFIS

The novel contribution of the current study is to employ adaptive neuro-fuzzy inference system (ANFIS) for evaluation of H₂-selective mixed matrix membranes (MMMs) performance in various operational conditions. Initially, MMMs were prepared by incorporating zeolite 4A nanoparticles into polydimethylsiloxane (PDMS) and applied in gas permeation measurement. The gas permeability of CH₄, CO₂, C₃H₈ and H₂ was used for ANFIS modeling. In this manner, the H₂/gas selectivity as the output of the model was modeled to the variations of feed pressure, nanofiller contents and the kind of gas, which were defined as input (design) variables. The proposed method is based on the improvement of ANFIS with genetic algorithm (GA) and particle swarm optimization (PSO). The PSO and GA were applied to improve the ANFIS performance. To determine the efficiency of PSO-ANFIS, GA-ANFIS and ANFIS models, a statistical analysis was performed. The results revealed that the PSO-ANFIS model yields better prediction in comparison to two other methods so that root mean square error (RMSE) and coefficient of determination (R²) were obtained as 0.0135 and 0.9938, respectively. The RMSE and R² values for GA-ANFIS were 0.0320 and 0.9653, respectively, and for ANFIS model were 0.0256 and 0.9787, respectively.     

Integration of a hybrid fuel cell-battery system to a distribution grid

In order to integrate a proton exchange membrane type (PEM) fuel cell system (FCS) combined with a battery bank to a distribution grid; this paper proposes a local controller based on fuzzy logic. The proposed system provides primary frequency control and local bus voltage support to the local grid. This opposes the passive distributed generation of the present that do not provide auxiliary services, such as back-up power, voltage support and reliability of supply as they operate under constant power factor equal to 1 at all times. During network disturbances, the distributed generations of the present are disconnected until normal operation is reestablished. When the distributed generation penetration is high this may lead to system instability. The microgrid concept is the effective solution for the control and quality improvement of grids with high level of DG penetration. So, the proposed system, also, can be an active controllable microsource of a microgrid in the future that cooperates with other microsources in order to cover the local load demands for active and reactive power either under grid-connected mode or under islanding operating mode. In cases where the distribution grid (working as microgrid) is forced to operate in islanded mode, the hybrid system provides the demanded active and reactive power. The FCS is connected to a weak distribution grid so that the system performance is studied under the worst conditions. The simulation results are obtained using MATLAB software under a severe step load change where the grid is still connected and under islanded operation. In both cases the system presents a good performance.     

An adaptive neural-fuzzy inference system (ANFIS) for detection of bruises on Chinese bayberry (Myrica rubra) based on fractal dimension and RGB intensity color

This paper introduces an adaptive neural-fuzzy inference system (ANFIS) model to detect bruises on Chinese bayberries as a function of fractal dimension (FD) and RGB intensity values. The ANFIS with different types of input membership functions (MFs) was developed. Our results showed that ‘gauss2mf’ MF performs much better than other mentioned MFs for defect inspection. The classification accuracy of the ANFIS with ‘gauss2mf’ MF was 100% and 78.57% for healthy and bruised fruits, respectively, and the total correct classification rate was 90.00%. Therefore, this study indicated the possibility of developing a potentially useful classification tool using the ANFIS technique based on FD and RGB values for detecting bruises of not only Chinese bayberries, but also of other fruits during processing, storage and distribution.     

Fuzzy modeling and simulation for lead removal using micellar-enhanced ultrafiltration (MEUF)

In the present paper, a three factor, three-level response surface design based on Box-Behnken design (BBD) was developed for maximizing lead removal from aqueous solution using micellar-enhanced ultrafiltration (MEUF). Due to extremely complexity and nonlinearity of membrane separation processes, fuzzy logic (FL) models have been driven to simulate MEUF process under a wide range of initial and hydrodynamic conditions. Instead of using mathematical model, fuzzy logic approach provides a simpler and easier approach to describe the relationships between the processing variables and the metal rejection and permeation flux. Statistical values, which quantify the degree of agreement between experimental observations and numerically calculated values, were found greater than 91% for all cases. The results show that predicted values obtained from the fuzzy model were in very good agreement with the reported experimental data.     

商空间下模糊系统性能一致性(鲁棒性)分析

通过模糊商空间(粒度计算)理论和模糊集的结构性定义,讨论了模糊控制系统模糊隶属度函数的变化对系统结构的影响,给出了模糊系统同构的充要条件．由模糊等价关系出发,证明了模糊控制器的鲁棒性问题,从而对于这个人们多年来一直争论的问题,在一定意义上给予了解决．通过MATLAB对实际控制系统的仿真,证实以上观点正确．     

Preparation, characterization and application of bilayer surfactant-stabilized ferrofluids

Fe₃O₄ magnetic nanoparticles (MNPs) were prepared by the coprecipitation of Fe²⁺ and Fe³⁺ using ammonium hydroxide (NH₄OH) as precipitating agent. Transmission electronic microscopy (TEM) showed that the particle-size is around 10 nm. X-ray powder diffraction (XRD) indicated the sole existence of inverse cubic spinel phase of Fe₃O₄. The surface of MNPs was coated with oleate sodium as the primary layer and polyethylene glycol 4000 (PEG-4000) as the secondary layer to improve the stability of water-based ferrofluids (FFs). The dosages of oleate sodium and PEG-4000 were found to have an important effect on increasing the solid content. Gouy magnetic balance showed that the saturation magnetization could be as high as 1.44 × 10⁵ A/m. Laser particle-size analyzer determined the aggregate size in FFs. The Fe₃O₄ MNPs did not change through the preparation of FFs. Differential scanning calorimetry-thermogravimetry (DSC-TG) and Fourier transform infrared spectroscopy (FT-IR) analysis showed existence of two distinct surfactants on the particle surface. The concentrated and diluted FFs were characterized by UV-vis spectrophotometer and excellent stability was found. The rheological measurements indicated that viscosity increased with the increase of solid content and applied magnetic field, but decreased with the increase of temperature. The FFs showed the non-Newtonian behavior of shear-thinning when the solid content was high. The mechanical properties of polyvinylalcohol (PVA) thin film can be greatly improved by adding FFs.