Corrosion effects on tension stiffening behavior of reinforced concrete

The investigation of corrosion effects on the tensile behavior of reinforced concrete (RC) members is very important in region prone to high corrosion conditions. In this article, an experimental study concerning corrosion effects on tensile behavior of RC members is presented. For this purpose, a comprehensive experimental program including 58 cylindrical reinforced concrete specimens under various levels of corrosion is conducted. Some of the specimens (44) are located in large tub containing water and salt (5% salt solution); an electrical supplier has been utilized for the accelerated corrosion program. Afterwards, the tensile behavior of the specimens was studied by means of the direct tension tests. For each specimen, the tension stiffening curve is plotted, and their behavior at various load levels is investigated. Average crack spacing, loss of cross-section area due to corrosion, the concrete contribution to the tensile response for different strain levels, and maximum bond stress developed at each corrosion level are studied, and their appropriate relationships are proposed. The main parameters considered in this investigation are: degree of corrosion (Cw), reinforcement diameter (d), reinforcement ratio (ρ), clear concrete cover (c), ratio of clear concrete cover to rebar diameter (c/d), and ratio of rebar diameter to reinforcement percentage (d/ρ)

Comparison of four models to predict intrinsic solubility of drugs

The aqueous solubility of drugs/drug candidates (Sw) is one of the crucial physicochemical parameters in drug discovery studies and any computational method to predict the solubility is highly in demand in the pharmaceutical industry. This work is aimed to compare the accuracy of a recently proposed model (logSw=-1.120E-0.599ClogP) composed of two computational descriptors; excess molar refraction (E) and calculated partition coefficient of octanol to water (ClogP) with the accuracies of the Hansch model, general solubility equation and linear solvation energy relationship model. These results showed that the prediction capability of the proposed model is better than those of three famous models and the E is a crucial descriptor for aqueous solubility prediction of drugs and drug-like molecules.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Effect of wind turbine generator model and siting on wind power changes out of large WECS arrays

Methods of reducing the WECS generation change through selection of the wind turbine model for each site, selection of an appropriate siting configuration, and wind array controls are discussed. An analysis of wind generation change from an echelon and a farm for passage of a thunderstorm is presented. Reduction of the wind generation change over ten minutes is shown to reduce the increase in spinning reserve, unloadable generation and load following requirements on unit commitment when significant WECS generation is present and the farm penetration constraint is satisfied. Controls on the blade pitch angle of all wind turbines in an array or a battery control are shown to reduce both the wind generation change out of an array and the effective farm penetration in anticipation of a storm so that the farm penetration constraint may be satisfied

Comparison of four models to predict intrinsic solubility of drugs

The aqueous solubility of drugs/drug candidates (Sw) is one of the crucial physicochemical parameters in drug discovery studies and any computational method to predict the solubility is highly in demand in the pharmaceutical industry. This work is aimed to compare the accuracy of a recently proposed model (logSw=-1.120E-0.599ClogP) composed of two computational descriptors; excess molar refraction (E) and calculated partition coefficient of octanol to water (ClogP) with the accuracies of the Hansch model, general solubility equation and linear solvation energy relationship model. These results showed that the prediction capability of the proposed model is better than those of three famous models and the E is a crucial descriptor for aqueous solubility prediction of drugs and drug-like molecules.Colegio de Farmacéuticos de la Provincia de Buenos Aire

A new approach for nonlinear finite element analysis of reinforced concrete structures with corroded reinforcements

A new approach for nonlinear finite element analysis of corroded reinforcements in reinforced concrete (RC) structures is elaborated in the article. An algorithmic procedure for producing the tension-stiffening curve of RC elements taking into consideration most of effective parameters, e.g.: the rate of steel bar corrosion, bond-slip behavior, concrete cover and amount of reinforcement, is illustrated. This has been established on both experimental and analytical bases. This algorithm is implemented into a nonlinear finite element analysis program. The abilities of the resulted program have been studied by modeling some experimental specimens showing a reasonable agreement between the analytical and experimental findings

Hypoelastic modeling of reinforced concrete walls

This paper presents a new hypoelasticity model which was implemented in a nonlinear finite element formulation to analyze reinforced concrete (RC) structures. The model includes a new hypoelasticity constitutive relationship utilizing the rotation of material axis through successive iterations. The model can account for high nonlinearity of the stress-strain behavior of the concrete in the pre-peak regime, the softening behavior of the concrete in the post-peak regime and the irrecoverable volume dilatation at high levels of compressive load. This research introduces the modified version of the common application orthotropic stress-strain relation developed by Darwin and Pecknold. It is endeavored not to violate the principal of “simplicity” by improvement of the “capability”. The results of analyses of experimental reinforced concrete walls are presented to confirm the abilities of the proposed relationships