Saturation exponent determination by using genetic algorithm in carbonate reservoirs: A case study in Sarvak Formation

Well logging analysis has been recognized as the best way to characterize reservoir properties, especially water saturation. Archie equation is known as the best method to estimate water saturation from well logging data. Determination of Archie parameters is an incessant challenge in advanced reservoir engineering because of its complex intrinsic. Measurement of Archie parameters in core laboratory has a high sensitive, expensive and time consuming procedure, that causes the excluding of core analysis to be impossible for the entire depth of reservoir zone. Although some empirical and mathematical models have been introduced to measure cementation factor, without the need of coring, there is not exist a reliable method to estimate saturation exponent in similar way.Genetic algorithm is excelled than other meta-heuristic global search methods, which could be used in solving engineering problems. In this study, a genetic algorithm based strategy has been developed to develop a model to estimate saturation exponent from a core of drilled well in Sarvak Formation at Marun Oil Field in Iran. This model has been validated with laboratory measurements of saturation exponent with the accuracy (R²) of 0.91 and the miscalculation (MSE) of 0.23.     

Surface Modification of Press Dies Used in a Powder Metallurgical Production Process

Cold compaction in a press die and subsequent sintering of diamond particles, homogeneously distributed in a metallic powder as matrix, is one of the most economic ways for the production of diamond composites, used widely for cutting very hard materials like stone and glass. Owing to the very high hardness of diamonds, the wear of the press die is considerably high and because of a short life time, press tools must be substituted regularly. Recently, through plasma nitriding process and deposition of thin solid films, the wear resistance of the press dies has been significantly increased. This work aims at the investigation of the influence of roughness, friction coefficient, and hardness of the inner surface of various dies, which have been modified in different ways, on the physical properties of the compacted diamond segments. It was evidenced that improving the mechanical and tribological properties of the die surface leads to an increase of the hardness and density of the diamond composites produced.     

Mechanisms of Natural Extracts of Andrographis paniculata That Target Lipid-Dependent Cancer Pathways: A View from the Signaling Pathway

Andrographis paniculata is a local medicinal plant that is widely cultivated in Malaysia. It is comprised of numerous bioactive compounds that can be isolated using water, ethanol or methanol. Among these compounds, andrographolide has been found to be the major compound and it exhibits varieties of pharmacological activities, including anti-cancer properties, particularly in the lipid-dependent cancer pathway. Lipids act as crucial membrane-building elements, fuel for energy-demanding activities, signaling molecules, and regulators of several cellular functions. Studies have shown that alterations in lipid composition assist cancer cells in changing microenvironments. Thus, compounds that target the lipid pathway might serve as potential anti-cancer therapeutic agents. The purpose of this review is to provide an overview of the medicinal chemistry and pharmacology of A. paniculata and its active compounds in terms of anti-cancer activity, primary mechanism of action, and cellular targets, particularly in the lipid-dependent cancer pathway.     

HamDroid: permission-based harmful android anti-malware detection using neural networks

Neural Computing and Applications - Android platforms are a popular target for attackers, while many users around the world are victims of Android malwares threatening their private information....     

Development of nanosilica-based catalyst for syngas production via CO2 reforming of CH4: A review

The alarming global warming issue has sparked interest in researchers to mitigate greenhouse gas emissions via CO₂ reforming of CH₄ (CRM). Regrettably, the main drawback of CRM is catalyst deactivation because of coking and metal sintering. Therefore, exceptional resistance towards coking and sintering is crucial to formulate viable CRM catalysts. This article reviewed the latest development of nanosilica-based catalysts (mesoporous nanosilica, dendritic fibrous nanosilica, green nanosilica, and core@shell nanosilica) for CRM application. The physicochemical properties of nanosilica supports could be modulated by synthesis methods to improve their resistance towards coking and sintering. Furthermore, this review compiled the influence of catalytic properties of nanosilica supported catalysts, such as active metal dispersion, crystallite size, acid-basic properties, oxygen mobility, reducibility, porosity, and morphology on CRM. To conclude, nanosilica supports with strong metal-support interaction, homogeneous metal dispersion, appropriate crystallite size, and moderate acidity/basicity, exhibited satisfactory catalytic activity, thermal stability, and resistance towards coking and sintering. The fundamental study and depth understanding on this catalysis field is of worth in configuring robust catalysts for future industrial applications success of CRM reaction with superb activity and carbon resistance for CRM.     

Effects of compositional variations on CO2 foam under miscible conditions

Foam can mitigate the associated problems with the gas injection by reducing the mobility of the injected gas. The presence of an immiscible oleic phase can adversely affect the foam stability. Nevertheless, under miscible conditions gas and oil mix in different proportions forming a phase with a varying composition at the proximity of the displacement front. Therefore, it is important to understand how the compositional variations of the front affect the foam behavior. In this study through several core‐flood experiments under miscible condition, three different regimes were identified based on the effects of the mixed‐phase composition on CO₂ foam‐flow behavior: In Regime 1 the apparent viscosity of the in‐situ fluid was the highest and increased with increasing x_CO2. In Regime 2 the apparent viscosity increased with decreasing x_CO2. In Regime 3 the apparent viscosity of the fluid remained relatively low and insensitive to the value of x_CO2. © 2017 American Institute of Chemical Engineers AIChE J, 64: 758–764, 2018     

Pd‐Ag/α‐Al2O3 Catalyst Deactivation in Acetylene Selective Hydrogenation Process

The selective hydrogenation of acetylene to ethylene over Pd‐Ag/α‐Al₂O₃ catalysts prepared by different impregnation/reduction methods was studied. The best catalytic performance was achieved with the sample prepared by sequential impregnation. A kinetic model based on first order in acetylene and 0.5th order in hydrogen for the main reaction and second‐order independent decay law for catalyst deactivation was used to fit the conversion time data and to obtain quantitative assessment of catalyst performances. Fair fits were observed from which the reaction and deactivation rate constants were evaluated. Coke deposition amounts showed a good correlation with catalyst deactivation rate constants, indicating that coke formation should be the main cause of catalyst deactivation.     

A new handoff management system for heterogeneous wireless access networks

In heterogeneous wireless access networks, each mobile terminal may frequently need to change its base station (BS); this change is called a ‘handoff’. BSs have static parameters, which are related to their radio access technologies (RATs); however, they also contain dynamic parameters such as load and signal quality. Therefore, the problem of handoff decision includes two subproblems of RAT selection and BS selection. In this paper, first a ‘heterogeneous handoff management system’ for gathering all different required parameters is proposed. Second, a RAT Selection algorithm based on analytic hierarchy process and a BS Selection algorithm based on data envelopment analysis are designed. Finally, by means of ‘weight restriction’ technique, we develop a method for studying the impact of RAT Selection parameters on the performance of the network. Simulation results indicate that RAT Selection parameters have significant impact on the bandwidth utilization, energy consumption and the whole satisfaction of the users in heterogeneous wireless access networks.Copyright © 2012 John Wiley & Sons, Ltd.