Task scheduling,resource provisioning,and load balancing on scientific workflows using parallel SARSA reinforcement learning agents and genetic algorithm

The Journal of Supercomputing - Cloud computing is one of the most popular distributed environments, in which, multiple powerful and heterogeneous resources are used by different user applications....     

Aggregation mechanism of bovine serum albumin based on collision factor by the population balance conservation law

This paper discusses a novel approach for exploring the aggregation mechanism of bovine serum albumin using collision factor. The population balance equation consisting of aggregation term was developed and solved by the moment method. Different experiments were implemented to account for effective parameters on protein aggregation and to measure variations in average size of aggregates formed in a time interval. This was done by taking pictures with a CCD camera on a sterio microscope. The pictures were exported to image processing software to analyze average number and size of aggregates. The collision factor appearing in population balance equation was optimized and declared as a global term.     

A flow rule incorporating the fabric and non-coaxiality in granular materials

Deficiencies of constitutive models in prediction of dilatancy are often attributed to simplifications associated with flow rules such as assumptions of isotropy and coaxiality. It is thus proposed here to develop a comprehensive flow rule for granular materials by including the effect of fabric and without the assumption of coaxiality. A second-order tensor is introduced as a fabric for the distribution of contact normals and contact forces. By using the energy principle in micro-mechanical scale and a suitable dissipation mechanism in granular materials, a stress-dilatancy relation is obtained. Fabric plays a “bridge-like” role in the dilatancy and non-coaxiality. Non-coaxialities between stress-strain-fabric are attributed to the non-coaxiality between stress-fabric and strain-fabric. In this formulation the constants for modeling fabric depend on non-coaxiality of the system rather than the history that determines such a state. Ability of this stress-fabric-dilatancy for modeling the non-coaxiality shows that this relation can predict the behavior of granular materials in the presence of the rotation of principal stress axes.     

Linearization design method in class-F power amplifier using artificial neural network

This paper represents the design of a class-F power amplifier (PA), its artificial neural network (ANN) model and a PA linearization method. The designed PA operates at 1.8 GHz with gain of 12 dB and 1dB output compression point (P1dB) of 36 dBm. The proposed ANN model is used to predict the output power of designed class-F PA as a function of input and DC power. This model utilizes the designed class-F PA as a block, which could be used in a desired linearization circuit. In addition, the power added efficiency (PAE) and the other specifications of a PA, related to power can be predicted using the proposed model. A simple feedforward technique is used to improve the linearity of designed PA. For verification, this linearization method is compared with presented neural network model simulations. The results show the improvement of P1dB from 36 to 41 dBm, which is predicted using the proposed model. Also, the PAE of the final linearized circuit PA is predicted.     

Three-dimensional modeling of system of vibrating spherical balls using discrete element method

The modeling of particulate systems has been an important focus of research worldwide, as these are fairly common in nature, such as rain drops in air, snowfall, and several industrial processes such as chemistry, agriculture, pharmaceutical, powder metallurgy, soil mechanics, casting, cement manufacturing, civil, and etc. In recent years, one of important aspects of the granular material physics in industries is controlling way of the granular flow. One of the best ways of controlling the flow is the use of mechanical vibrations to guide the particles in desirable way. In this paper the effect of horizontal harmonic vibration on the particles flow is theoretically and experimentally investigated. During the base vibration, the spherical particles collide with each other and with the walls as well, causing a global pattern of particle motion which is interpreted as flow. The motion of spherical particles and the interaction forces due to the vibration is obtained numerically via discrete element method (DEM). Finally, the presented numerical model is compared with the experimental one and a good agreement between them is noticed.     

The influence of addition of carbon nanotube and graphene platelets on characteristics of carbon/basalt fiber reinforced intra-ply hybrid composites

In this study, effects of addition of carbon nanotubes (CNTs) and graphene platelets (GPLs) on characteristics of carbon/basalt fiber reinforced intra-ply hybrid composites were investigated. The composites were fabricated using vacuum assisted resin infusion molding (VARIM) method in two types including bare and 0.1, 0.5 wt.% of GPL and CNT nanoparticles filled hybrid composites. Fabricated normal and multiscale composites were cut by water jet and mechanical properties of specimens were examined by tensile, flexural, SBS experiments. Therefore, the modulus of elasticity, flexural modulus, tensile and flexural strength and ILSS of bare and multiscale composites were compared. Thermomechanical properties of fabricated composites were evaluated by dynamic mechanic analyze (DMA), thermogravimetric analyze ( TGA) and thermal conductivity (TC) tests and storage modulus, loss modulus, damping ratio, glass transition temperature, weight loss and derivative weight loss were compared in fabricated normal and multiscale composites. Similarly, modal properties of fabricated composites such as natural frequency and damping factor were obtained by vibrational tests and compared in fabricated composites. According to the results, the addition of carbon-based nanoparticles improved the characteristics of carbon/basalt fiber intra-ply hybrid composites. The response of composites was directly proportional to the addition ratio of the carbon-based nanoparticles.     

Investigation of the corrosion behavior of 304L and 316L stainless steels at high-temperature borated and lithiated water

The effects of temperature and dissolved oxygen on the electrochemical behavior and the oxide film formation of grades 304L and 316L stainless steels at high-temperature borated and lithiated water were investigated by means of potentiodynamic polarization, scanning electron microscopy and X-ray photoelectron spectroscopy. The results revealed that increasing the solution temperature degrades the passivity of the oxide films formed on both grades of steel and shifts their corrosion potential toward more negative potentials. The oxide films formed on the steel samples immersed into the solution containing 20 ppb dissolved oxygen (DO) showed a duplex structure, in which the inner layer was mostly a composition of Cr oxides and the outer layer mainly was a Fe oxide and Ni–Fe spinel. Only a single layer of Cr-rich oxide was observed in the oxide films formed in the solutions with the DO concentrations higher than 20 ppb. Higher amount of Cr in the oxide films formed on the type 316L compared to 304L improves the passivity of the oxide film of this grade of steel and results in a wider passive region in its potentiodynamic polarization curves.     

A simplified method for collapse capacity assessment of moment-resisting frame and shear wall structural systems

A simplified methodology for predicting the median and dispersion of collapse capacity of moment-resisting frame and shear wall structural systems subjected to seismic excitations is proposed. The method is based on nonlinear static (pushover) analysis. Simple mathematical models denoted as “generic structures” are utilized to model moment-resisting frames and shear walls. After examining a wide range of structural parameters of the generic structures, a comprehensive database of collapse fragilities and pushover curves (using ASCE 7-05 lateral load pattern) are generated. Based on the obtained pushover curves, closed-form equations for estimation of median and dispersion of building collapse fragility curves are developed using multivariate regression analysis. Comparing the estimates of the median collapse capacity calculated from the closed-form equations with the actual collapse capacities determined from nonlinear response-history analysis indicates that the simplified methodology is reliable. The effectiveness of this methodology for predicting the median collapse capacity of frame and wall structures is further demonstrated with two case studies of structural systems designed based on current seismic provisions.     

Imidazolium-based Alkylsulfate Ionic Liquids and Removal of Sulfur Content From Model of Gasoline

Two ionic liquids, butyl-methyl-imidazolium octylsulfate, [BMIM][OCSO₄], and ethyl-methyl-imidazolium ethylsulfate, [EMIM][EtSO₄], were demonstrated to be effective for the removal of aromatic sulfur compounds such as benzothiophene and thiophene from model of gasoline. Organic compounds with higher aromatic π-electron density were favorably adsorbed by using ionic liquids. It was shown that the extractive ability of the alkylsulfate IL_s was dominated by the structure and size of cation and anion. The cation and anion structure and size of ionic liquids are important factors affecting the absorption capacity for aromatic compounds. It is found that [BMIM][OCSO₄] has the best effect on the selective removal of sulfur compounds from gasoline. Sulfur extractive selectivity for specified IL followed the order BT>T>3-MT>2-MT.