Thermal conductivity and dynamic viscosity modeling of Fe2O3/water nanofluid by applying various connectionist approaches

Abstract

Thermal conductivity and dynamic viscosity play key role in heat transfer capacity of nanofluids. In the present study, thermal conductivity and dynamic viscosity of Fe₂O₃/water are modeled by applying various artificial neural network algorithms. The applied algorithms are MLP, GA-RBF, LSSVM, and CHPSO ANFIS algorithms. The data for modeling procedure are extracted from several experimental studies. Obtained results by the different algorithms are compared and it was concluded that the highest R-squared values belonged to GA-RBF algorithm which were equal to 0.9962 and 0.9982 for thermal conductivity ratio and dynamic viscosity, respectively.     

A diagnosis method for identification of the defected cell(s) in the PEM fuel cells

Incorrect controlling of the pressure, temperature, flow rate and humidity levels of reactant gases can inflict severe and sometimes irreversible damages on the PEM fuel cells. Most important damage is leakage between the two sides of cathode and anode that may lead to physical defects in the stack. Usage of neutral gas method only reveals the overall leakage and does not show the exact location of the defected cell in the stack. This research seeks to determine the exact location of the defective cell using a method that is based on the data received from the voltage–time graphs of the stack under hydrogen sudden stop condition when the stacks are operating in the open circuit voltage condition. This method has been used with respect to two fuel cell stacks with different powers in different working conditions. Also the stack voltage drop due to leakage has been considered theoretically.     

Fabrication of Novel Membranes for Biomedical Applications via Halidation of Poly(Methacrylic Acid‐co‐Methyl Methacrylate) and Crosslinking of Complementary Groups by PEG

Fabrication of novel, biocompatible and stimuli‐responsive membranes based on the crosslinking of poly(methacrylic acid‐co‐methyl methacrylate) using polyethylene glycol as a crosslinking agent is accomplished in a two‐stage procedure. Membranes are fabricated by casting and curing of the reactive precursors in different reaction compositions and durations according to a three‐level factorial design‐of‐experiments. The resulting membranes were thoroughly characterized using SEM, FTIR spectroscopy, thermal analysis and swelling experiments. The thermal properties were improved and swelling behavior of the hydrogels assures its stimuli‐responsive nature. MTT‐assay and cytotoxicity evaluations of the fabricated membranes elucidate acceptable biocompatibility profiles.     

Molecular dynamics study for CH4/H2S separation through functionalized nanoporous graphyne membrane

Molecular dynamics simulations were employed to investigate the effect of chemical functionalization and applied pressure on the CH₄/H₂S separation performance using graphyne as a membrane. A pore was created on the graphyne surface and then functionalized with hydroxyl group and fluorine. The number of methane and hydrogen sulfide molecules in the simulated systems was 100 molecules from each of them, which were placed between graphyne and graphene nanosheet as a barrier. The results indicated that nanoporous graphyne can be suitable membrane for gas separation, especially in the absence of applied pressure, which is an acceptable condition for gas separation systems.     

Uncertainty Assessment of the Integrated Hybrid Data Processing Techniques for Short to Long Term Drought Forecasting in Different Climate Regions

Water Resources Management - Accurate prediction of drought indices is a useful method to reduce its undesirable consequences. In this study, the workability of newly integrated hybrid forecasting...     

Corrosion evaluation of Ti–6Al–4V manufactured by electron beam melting in Ringer’s physiological solution: an in vitro study of the passive film

Journal of Applied Electrochemistry - Electrochemical characteristics and semiconducting behavior of additively manufactured electron beam melted (EBM) and wrought (WR) Ti–6Al–4V...     

Difference-based target detection using Mahalanobis distance and spectral angle

Two difference-based target detection methods are proposed in this work. In contrast to many target detectors which only calculate the distance between the testing pixel to the target spectrum, the proposed methods calculate the distance of the testing pixel to both of target and of background spectra. In other words, they utilize the difference between target and background computed distances. The first proposed method uses the Mahalanobis distance and benefits the valuable information contained in the statistics of targets and background. The second proposed method uses the kernel-based spectral angle mapper to benefit the advantages of spectral angle and kernel trick to separate targets from background, especially in non-linear cases. The experiments done on three real hyperspectral images indicate the high detection probability of the proposed methods compared to several target detectors.