A Novel Stochastic Approach for Optimization of Diversion System Dimension by Considering Hydrological and Hydraulic Uncertainties

Water Resources Management - This study proposes a new stochastic approach for optimizing diversion system design and its construction schedule by considering different hydrological and hydraulic...     

Prediction of heavy oil viscosity using a radial basis function neural network

Heavy oil and extra heavy oil resources comprise about 75% of petroleum resources. The most important characteristic of heavy oils is their viscosity. Consequently, to extract and prepare these kinds of crude oil for use, great emphasis should be put on viscosity. The present study highlights the application of intelligent model named radial basis function (RBF) network optimized by genetic algorithm for estimation of diluted heavy oil viscosity in presence on kerosene. The input parameters of model were temperature and mass fraction of kerosene. The output of model was viscosity of heavy oil. Genetic algorithm was utilized to optimize the tuning parameters of RBF model. The outcomes of this study showed that the proposed model is accurate in estimation of target data.     

Numerical simulation of heat transfer and fluid flow of molten metal in MMA–St copolymer lost foam casting process

In this study, a computational fluid dynamics (CFD) code was developed to calculate the filling pattern using volume of fluid (VOF) algorithm with donor–acceptor method for free surface simulation. This algorithm has been modified to include the pressure of the gas produced from foam degradation. For this purpose a heat transfer model and 2D foam degradation model were developed. In heat transfer model, radiation and conduction between foam and molten metal; and convection between gas and molten metal were considered. In order to evaluate the results of simulation, a bench scale casting apparatus was assembled and the casting was conducted in a transparent mold. The effect of several parameters such as coating thickness, foam density and vacuum level on the gap temperature, gap pressure and filling speed was studied with the developed software. It was found that the simulated results are in good agreement with experimental results.     

Experimental investigation of effect of palmitic acid as inhibitor on particle size of asphaltenes flocs using imaging techniques

In this article, the effect of one well-known inhibitor namely palmitic acid is investigated on particle size distribution of asphaltenes by imaging techniques. Pure asphaltene is extracted from crude oil to prepare Heptol (n-heptane+toluene) solutions of suspended asphaltenes. Different concentrations of inhibitors are then added to the solution. Afterward, image analysis of microscopic photos is used to determine the particle size distribution of asphaltene flocs in the presence of inhibitors. Average particle size of asphaltene and fractal structure of aggregates are also investigated; results show that the compaction of asphaltenes flocs is correlated with concentration of inhibitor. However, no significant relationship was observed between surface roughness of flocs and inhibitor concentration.     

Enhancement of mechanical and thermal properties of polycaprolactone/chitosan blend by calcium carbonate nanoparticles

This study investigates the effects of calcium carbonate (CaCO(3)) nanoparticles on the mechanical and thermal properties and surface morphology of polycaprolactone (PCL)/chitosan nanocomposites. The nanocomposites of PCL/chitosan/CaCO(3) were prepared using a melt blending technique. Transmission electron microscopy (TEM) results indicate the average size of nanoparticles to be approximately 62 nm. Tensile measurement results show an increase in the tensile modulus with CaCO(3) nanoparticle loading. Tensile strength and elongation at break show gradual improvement with the addition of up to 1 wt% of nano-sized CaCO(3). Decreasing performance of these properties is observed for loading of more than 1 wt% of nano-sized CaCO(3). The thermal stability was best enhanced at 1 wt% of CaCO(3) nanoparticle loading. The fractured surface morphology of the PCL/chitosan blend becomes more stretched and homogeneous in PCL/chitosan/CaCO(3) nanocomposite. TEM micrograph displays good dispersion of CaCO(3) at lower nanoparticle loading within the matrix.     

Numerical simulation of roughness effects on flow and heat transfer in microchannels at slip flow regime

A numerical simulation for studying fluid flow and heat transfer characteristics in microchannels at slip flow regime with consideration of slip and temperature jump is studied. The wall roughness is simulated in two cases with periodically distributed triangular microelements and random shaped micro peaks distributed on the wall surfaces. Various Knudsen numbers have used to investigate the effects of rarefaction. The numerical results have also checked with available theoretical and experimental relations and good agreements has achieved. It has been found that rarefaction has more significant effect on flow field in microchannels with higher relative roughness. The negative influence of roughness on fluid flow and heat transfer found to be the friction factor increment and Nusselt number reduction. In addition high influence of roughness distribution and shape has been shown by a comparison of Poiseuille and Nusselt numbers for tow different cases.     

Improvement of the dyeing and fastness properties of a naphthalimide fluorescent dye using poly(amidoamine) dendrimer

In this study, 4‐amino‐9‐methoxypropylnaphthalimide fluorescent dye (dye 1 ) was reacted with poly(amidoamine) dendrimer G = ?0.5 to prepare a naphthalimide–dendrimer hybrid dye (dye 2 ). The chemical structures of the synthesised dyes were confirmed by elemental analysis, Fourier transform infrared spectroscopy, ¹H nuclear magnetic resonance spectroscopy, and ultraviolet‐visible spectroscopy. The solvatochromism of the dyes was evaluated in various solvents with respect to visible absorption properties, and positive solvatochromism was observed by solvent polarity change from chloroform to ethanol. The dyeing ability of the synthesised dyes was investigated by their application onto nylon fabric, and nylon substrates dyed with dye 2 exhibited marked enhancement both in terms of colour strength and general fastness properties. The results of this study clearly demonstrated the high potential and performance of dye 2 as a novel promising fluorescent dye as compared with dye 1 . Overall, it was inferred that the modification of the naphthalimide fluorescent dye with poly(amidoamine) denderimer could markedly improve the dyeing and fastness properties of the naphthalimide fluorescent dye on nylon fabrics.     

A model for estimation of permeability and free flowing porosity

This work highlights the application of an adaptive neuro-fuzzy inference system (ANFIS) for predictions of NMR log parameters including free flowing porosity (FFP) and permeability by using field log data. The input parameters of model were neutron porosity, sonic transit time, bulk density, and electrical resistivity. The outputs of model were also permeability and FFP values. The ANFIS model was trained by using hybrid method. Results showed that the developed model is effective in prediction of field NMR log data. Outcomes of this study can be used in areas of petroleum engineering where accurate and immediate predictions of logging data are required.