Application of Fuzzy c-means algorithm for the estimation of Asphaltene precipitation

One of problematic topics in petroleum engineering is Asphaltene precipitation issue which causes problems such as tubing plugging and formation damage due to temperature, pressure and composition changes so the notability of this issue increases. In the present investigation a novel Fuzzy c-means (FCM) algorithm was developed to predict precipitated asphaltene as function of dilution ratio, carbon number of precipitants and temperature for solving the problem. The results showed that this novel approach has great ability to predict precipitated asphaltene in terms of aforementioned parameters. The coefficients of determination (R²) for training and testing steps are calculated as 0.9828 and 0.9387 respectively. This great degree of accuracy expresses that the predicting algorithm has potential to be utilized as software for prediction of asphaltene behavior.     

Improvement of the oral bioavailability of coenzyme Q10 by emulsification with fats and emulsifiers used in the food industry

Coenzyme Q₁₀ (CoQ₁₀) was emulsified with fats and emulsifiers commonly used in the food industry, and the oral bioavailability of the emulsified product was compared with that of a standard commercial product. Five commonly used fats (olive oil, safflower oil, coconut oil, butter, and cocoa butter), four types of emulsifier (lecithin, monoglycerides, calcium stearoyl-2-lactate (CSL), and diacetyl tartaric acid esters of monoglycerides), and two types of aqueous phase (distilled water with or without 8 g/100 g w/w skim milk) were employed in this study. It was found that CoQ₁₀ was more soluble in coconut and safflower oils than in the other fats. In addition, it was demonstrated that emulsion with coconut oil, skim milk aqueous solution, and CSL produced an optimal formulation. Based on the results, a model emulsified CoQ₁₀ product was prepared. Its oral bioavailability was confirmed to be slightly greater than that of a standard commercial CoQ₁₀ product.     

A parametric study of coupled‐mode flutter for MW‐size wind turbine blades

With the increasing size of offshore wind turbine rotors, the design criteria used for the blades may also evolve. Current offshore technology utilizes three relatively stiff blades in an upwind configuration. With the goal of minimizing the mass, there is an interest in the lightweight rotors that instead utilize two flexible blades oriented downwind. These longer blades are more flexible and thus susceptible to experience flow‐induced instability. Coupled‐mode flutter is one of the destructive aeroelastic instabilities that can occur in flexible structures subjected to aerodynamic loading. Because of variation in one of the system parameters, e.g., flow velocity, structural modes coalesce at a critical flow velocity, and coupled‐flutter occurs. In the present work, a parametric study is conducted in order to study the influence of the natural frequencies in the torsional and flapwise directions on the critical flutter speed for wind turbine blades. Three MW‐size wind turbine blades are studied using a three‐dimensional blade model, which includes coupled flapwise and torsional displacements. The results show that the three blades have very similar behavior as the system parameters vary. It is shown that the first torsional natural frequency and the ratio of the first torsional natural frequency to the first flapwise natural frequency are the most critical parameters affecting the onset of instability. Critical flutter speeds even lower than the blade rated speed can be observed for blades with low torsional natural frequencies. Copyright © 2015 John Wiley & Sons, Ltd.     

Polyaniline grafted chitosan/GO-CNT/Fe3O4 nanocomposite as a superior electrode material for supercapacitor application

Developing appropriate stable electroactive electrode materials for supercapacitor application is the challenging issue, which attracts enormous attention in recent decades. In this regard, Fe₃O₄ nanoparticles are firstly synthesized on chitosan/graphene oxide-multiwall carbon nanotubes (CS/GM/Fe₃O₄). Then, polyaniline (PANI) is grafted on it via in situ chemical polymerization and named as CS/GM/Fe₃O₄/PANI. The as-prepared nanocomposites are characterized by Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectroscopy. The capacitive properties of the electrodes are investigated in a three electrode configuration in 0.5 M Na₂SO₄ electrolyte by various electrochemical techniques. The specific capacitance of CS/GM/Fe₃O₄/PANI electrode is 1513.4 Fg⁻¹ at 4 Ag⁻¹ which is 1.9 times higher than that of CS/GM/Fe₃O₄ (800 Fg⁻¹). Meanwhile, the electrodes exhibit appropriate cycle life along with 99.8% and 93.95% specific capacitance at 100 Ag⁻¹ for chitosan/GO-CNT/Fe₃O₄ and polyaniline grafted chitosan/GO-CNT/Fe₃O₄, respectively.     

Characterization of deep‐fat frying in a wheat flour–water mixture model using a state diagram

BACKGROUND: Crispness is an important characteristic to be controlled in deep‐fat fried products. The physical state of food polymers influences the development of cellular structure and textural qualities of fried food. Glassy state is believed to play an important role in the mechanical properties of low‐moisture food. Therefore, an understanding of the physicochemical phenomena in the development of fried food structure using a state diagram of the frying process is discussed. RESULTS: Wheat flour models containing 400 and 600 g kg^?1 initial moisture content were fried in frying oil at 150 °C for 1–7 min. Thermal properties of wheat flour, structure alteration and textural properties of fried samples were evaluated. The porous structure continuously enlarged when the sample was in the rubbery state. As the frying time was prolonged, the state of the product became glassy due to a decrease in water content, resulting in the ceasing of porous enlargement. Conclusion: The results revealed that physicochemical changes during frying influence the alteration of microstructure and quality of fried food, and the state diagram could be applied to explain the formation of microstructure during the frying process and used as a decision‐making tool to choose the proper conditions to provide desirable qualities in fried food. Copyright © 2007 Society of Chemical Industry     

Characteristics and oil absorption of deep‐fat fried dough prepared from ball‐milled wheat flour

BACKGROUND: High levels of oil in fried products has been recognized as causing health problems. The formation of microstructure during frying is one factor that influences oil absorption. Above the glass transition temperature (T_g), the physical properties of a polymer influences the formation of structure. The ball‐milling process changes the physicochemical properties of wheat flour constituents. The present study investigated the effects of physicochemical changes in wheat flour by the ball‐milling process on structure formation and oil absorption in wheat flour dough model. RESULTS: Dough samples were made from wheat flour that had been ball‐milled for 0 to 10 h and then fried in frying oil at 150 °C for 1–7 min. Thermal properties of wheat flour, structure alteration, and textural properties of fried samples were evaluated. As compared with samples made of non‐milled flour, samples made from milled flour had smaller pores and higher oil absorption. The fracture force of a fried sample prepared from non‐milled flour was lower than that of a sample prepared from milled flour. CONCLUSION: Ball‐milling affected the microstructure formation in fried wheat flour dough, and subsequently oil absorption. The crispness of a sample prepared from non‐milled wheat flour is higher than that of a sample prepared from ball‐milled wheat flour. This may be due not only to a plasticization effect, but may also be dependent on microstructure. Copyright © 2008 Society of Chemical Industry     

Optimal sliding mode control of drug delivery in cancerous tumour chemotherapy considering the obesity effects

Different control strategies have been proposed for drug delivery in chemotherapy during recent years. These control algorithms are designed based on dynamic models of various orders. The order of the model depends on the number of effects considered in the model. In a recent model, the effect of obesity on the tumour progression and optimal control strategy in chemotherapy have been investigated in a fifth‐order state‐space model. However, the optimal controller is open loop and not robust to the common uncertainties of such biological system. Here, the sliding surface is obtained by the optimal trajectory and by considering uncertainties of some parameters, the robust‐sliding control law is formulated in a way to slid on the optimal surface. Then, a sliding mode controller is designed to determine the drug dose rate such that the system follows the optimal desired trajectory. The stability of the control system is proved and the simulation results indicate that three states track the trajectory and the remaining two states satisfy the constraints.Inspec keywords: drug delivery systems, drugs, tumours, cancer, optimal control, open loop systems, controllers, medical control systemsOther keywords: optimal sliding mode control, drug delivery, cancerous tumour chemotherapy, obesity effects, control algorithms, dynamic models, tumour progression, optimal control strategy, fifth‐order state‐space model, open loop, biological system, sliding surface, optimal trajectory, robust‐sliding control law, sliding mode controller, drug dose rate     

A novel MLP-ANN approach to predict solution gas-oil ratio

Abstract

The better understanding and estimation of reservoir fluids properties have straight effects on accuracy of different processes such as simulation, well testing, and material balance calculations, so importance of accurate estimation of PVT properties such as solution gas-oil ratio is obvious. To this end, in the present paper, multilayer perceptron artificial neural network (MLP-ANN) is used as a novel predictive tool to estimate solution gas-oil ratio in terms of temperature, bubble point pressure, oil American Petroleum Institute gravity API, and gas specific gravity. Therefore, a total number of 1,137 experimental solution gas-oil ratios has been gathered from reliable databank for evaluation of model outputs. The different graphical and statistical analyses such as determination of average absolute relative deviation (AARD), the coefficient of determination (R²) and root mean square error (RMSE) were used to evaluate the performance of MLP-ANN algorithm. The comparisons show that MLP-ANN algorithm has great accuracy in prediction of solution gas-oil ratio, so it can be used as a simple tool to predict phase behavior of reservoir fluids.     

Effects of ball‐milling on the glass transition of wheat flour constituents

BACKGROUND: Starch and gluten, the major components of wheat flour, greatly influence the structural characteristics of food products made with wheat flour. The effects of ball‐milling on the change in the semicrystalline structure of starch granules to the amorphous state have been reported. However, the effects of ball‐milling of native wheat flour on physicochemical changes in wheat flour constituents have not been elucidated. Therefore in this study the effects of ball‐milling on the glass transition of wheat flour constituents were investigated. RESULTS: Crude gluten, non‐gluten proteins and separated starch were obtained from wheat flour ball‐milled for 0–10 h, and the glass transition temperature (T_g) of these constituents was evaluated. The T_g of all wheat flour constituents decreased with increasing ball‐milling time. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that changes in band position and intensity did not occur for gluten but did occur for non‐gluten proteins. X‐ray diffraction revealed decreased crystallinity and greater plasticisation by water in separated starch as the ball‐milling time was prolonged. CONCLUSION: The results showed that the ball‐milling process decreased the T_g of wheat flour constituents as a function of milling time. The decrease in T_g was probably due to changes in conformation of protein subunits in gluten and depolymerisation of the non‐gluten protein fraction. The information obtained here about the physical alteration of wheat flour constituents may enhance the ability to successfully use ball‐milled wheat flour in food applications. Copyright © 2008 Society of Chemical Industry     

Characteristics and oil absorption in deep‐fat fried batter prepared from ball‐milled wheat flour

BACKGROUND: The porous structure generated during frying influences oil absorption and textural qualities. The alteration in physical properties of wheat flour is suspected to affect the structure formation. The present study investigated the effect of physicochemical changes in wheat flour by the ball‐milling process on structure formation and consequently oil absorption of a fried wheat flour batter model. RESULTS: Batter models containing 600 g kg^?1 moisture were made of 0–10 h ball‐milled wheat flour and then fried in frying oil at 150 °C for 1–7 min. The samples made of milled flour possess larger pores and exhibit lower oil absorption than sample made of 0 h milled flour. The fracture force of a fried sample prepared from 5 and 10 h milled flour is lower than that of a sample prepared from 0 h milled flour. CONCLUSION: The decrease in glass transition temperature (T_g) and melting temperature (T_m) of milled flour affect the microstructure formation in the fried wheat flour batter. The microstructure is responsible for oil absorption and fracturability in fried food. The samples made of flour of longer ball‐milling time have lower oil absorption and higher crispness. Ball‐milling may be a tool to produce mechanically modified wheat flour which can reduce oil absorption for fried batter. Copyright © 2009 Society of Chemical Industry