81 research outputs found
New structure for exact solutions of nonlinear time fractional Sharma-Tasso-Olver equation via conformable fractional derivative
In this paper new fractional derivative and direct algebraic method are used to construct exact solutions of the nonlinear time fractional Sharma-Tasso-Olver equation. As a result, three families of exact analytical solutions are obtained. The results reveal that the proposed method is very effective and simple for obtaining approximate solutions of nonlinear fractional partial differential equations
Stability analysis of Hilfer fractional differential systems
In this paper, we present some remarks on the stability of fractional order systems with the Hilfer derivative. Using the Laplace transform, some sufficient conditions on the stability and asymptotic stability of autonomous and non-autonomous fractional differential systems are given. The results are obtained via the properties of Mittag-Leffler
functions and the non-standard Gronwall inequality
Shear strengthening of damaged reinforced concrete beams with hybrid composite plates
This paper aims to evaluate experimentally the potentialities of Hybrid Composite Plates (HCPs) technique for the shear strengthening and repairing of reinforced concrete (RC) beams. HCP is a thin plate of Strain Hardening Cementitious Composite (SHCC) reinforced with Carbon Fiber Reinforced Polymer (CFRP) laminates. For this purpose, an experimental program composed of four Rectangular and five T-cross section beams was executed to assess the strengthening efficiency of HCPs technique. There were two control beams without any type of shear reinforcement, and seven beams strengthened with HCPs. The HCPs were applied to the lateral faces of the beams by using a combination of epoxy adhesive and mechanical anchors. The bolts were applied with a certain torque in order to increase the concrete confinement. To have a better understanding of the shear behavior of SHCC material, Iosipescu shear tests were carried out, and the results were used to derive their fracture mode II parameters.
To further explore the potentialities of the HCPs technique for the shear strengthening, the experimental tests were simulated numerically by a FEM-based computer program considering the material properties obtained experimentally. After demonstration of the good predictive performance of the numerical model, a parametric study was executed to investigate the influence of some parameters on the load carrying capacity of the strengthened beams, namely: i) Use a mortar instead of the SHCC; ii) application of different applied torque level to the mechanical anchors; iii) different bond condition between HCPs and concrete substrate.Clever Reinforcement Iberica for providing the CFRP laminates and epoxy, Sika for the sand and adhesive, Grace for the superplasticizers, Dow Chemical Co. for viscous modifying agents, ENDESA Compostilla power station for the fly ash, and Casais for assisting in the execution of the beams. FCTinfo:eu-repo/semantics/publishedVersio
An experimental study for characterization of size-dependence in microstructures via electrostatic pull-in instability technique
This paper experimentally investigates the size-dependent effective Young's modulus (Eeff) of aluminum (Al) clamped-clamped microbeams using the electrostatic pull-in instability technique. This study presents an experimental characterization of the so-called “length scale parameter” in couple stress theory and surface elasticity. Eeff is retrieved from the measured pull-in voltage, of the clamped-clamped beams with different dimensions, via an electromechanically coupled equation. Measurement results show a strong size dependence of Eeff for the Al beams in small sizes. The Young's modulus increases monotonously as the beams become thinner. The experimental observations are consistent with the published modeling results of the size effects, in which couple stress theory and surface elasticity theory are taken into consideration. The presented experimental method has substantial advantages such as precise adjustable magnitude of the non-contacting force and a lower cost over the other approaches used for characterization of micro-/nanoelectromechanical systems. This simple and reproducible method can be extended for characterization of various materials with different sizes and boundary conditions
Variation Iteration Method for Solving Ethanol and Acetaldehyde Concentrations in a Fixed Bed Laboratory Reactor
In this paper, we investigate the effects of nonlinear behaviour of the dimensionless concentrations of the ethanol and acetaldehyde in a fixed bed laboratory reactor. The work is based on solving the nonlinear differential equation of concentration of the ethanol and acetaldehyde by means of the He’s variational iteration method (VIM). Also, the numerical simulation (4th order Runge – Kutta method) is reported using Matlab software. The analytical solutions are compared with numerical results in order to achieve conclusions based on not only for accuracy and efficiency of the solutions, but also the simplicity of the taken procedures which would have remarkable effects on the time devoted for solving process. The analytical result reported in this work is useful to understand the behaviour of the system. Furthermore, due to the accuracy and convergence of obtained solutions, it is proved that the VIM could be applied through other nonlinear problems even with high nonlinearity
Abundant optical soliton solutions for an integrable (2+1)-dimensional nonlinear conformable Schrödinger system
Abstract The analytical solutions of the integrable generalized ( 2 + 1 ) -dimensional nonlinear conformable Schrodinger (NLCS) system of equations was explored in this paper with the aid of three novel techniques which consist of ( G ′ / G ) -expansion method, generalized Riccati equation mapping method and the Kudryashov method in the conformable sense. We have discovered a new and more general variety of exact traveling wave solutions by using the proposed methods with a variety of soliton solutions of several structures. With several plots illustrating the behavior of dynamic shapes of the solutions, the findings are highly applicable and detailed the physical dynamic of the considered nonlinear system
N-Acetylcysteine Overdose: A Case Report
Background: N-Acetylcysteine (NAC) is a cost-effective antioxidant and very useful treatment for several diseases. Methods: Here we report a rare case of iatrogenic NAC overdose following the mistake in calculation of the loading dose. Results: The patient was 14 years old girl referred to a local hospital due to history of intentional ingesting about 7grams acetaminophen. The physician prescribed her 6 grams NAC as a loading dose but 42grams NAC were infused by mistake. After infusion, the patient showed signs of anaphylactic shock and then transferred to Imam Reza toxicology-unite with weakness, lethargy, extreme fatigue, nausea, and dizziness. NAC overdosing, in a short period of time, led to coagulopathy, reduced platelet count, acute renal failure and metabolic acidosis. After 24 h, the patient died. The Medical forensic examination showed minor lung hemorrhage and presence of little amount of Aluminum phosphide in tissues they did not find no vital organ hemorrhage. It is unclear related to NAC overdose, phosphine intoxication or synergic effects. Conclusion: Massive transfusion of NAC was associated with impairment of coagulation factors, intracranial hypertension, renal failure and metabolic acidosis. Thus, NAC administration should be with caution. The medical history of patients committed suicide are not always accurate and complete evaluation are recommended
Optical soliton solutions of the generalized non-autonomous nonlinear Schrödinger equations by the new Kudryashov's method
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Separation of Oil Pollution Plumes of Groundwater in The Industrial Area of South Tehran
Due to the high volume of oil activities, there is a possibility of groundwater oil pollution, which requires extensive source identification, remediation, management and monitoring. In Rey industrial area, despite widespread oil pollution, the source identification of groundwater oil pollution has not been carried out before the present study, and previous studies were limited to exploration and extraction of petroleum products. The purpose of this study was to determine and separate the sources of oil spills to groundwater in the Rey industrial area. For this purpose, subsurface geology and hydrogeology of the region were studied by digging exploratory wells and data analyzing, and a conceptual model of the region was prepared. Then, all potential sources of pollutants and monitoring wells in the area were sampled and distillation and gas chromatography-mass spectrometry and hydrogeological analyzes were performed. Based on the results of this study, five main contaminated plumes were identified. The research results show that if the contamination is single product, the distillation method is the fastest and cheaper method of identifying and separating the plumes of contamination. When the contamination is a combination of different compounds, the use of gas-mass chromatography analysis and different ratios of the compounds along with hydrogeological analyzes is required. The main leaks in the study area were from the transmission lines of petroleum products buried in the underground, which usually transport petroleum products with high pressure
New classifications of nonlinear Schrödinger model with group velocity dispersion via new extended method
This work investigates the nonlinear Schrödinger equation (NLSE) with group velocity dispersion and second order spatiotemporal dispersion coefficients. The governing model is reduced into the classical nonlinear ordinary differential equation. Extended direct algebraic method (EDAM) is implemented to construct many novel mixed dark, and complex optical solutions. As a result, some important analytical solutions such as travelling mixed dark, and complex travelling wave solutions for the model are extracted.</p
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