Soltani-Jigheh H.,Shahid Madani University of Azarbaijan |
Asadzadeh M.,Islamic Azad University at Zanjan |
Marefat V.,Bonab University
Turkish Journal of Engineering and Environmental Sciences | Year: 2013
Some important engineering characteristics of compacted clay liners can be adversely affected by desiccation cracking, resulting in the loss of effectiveness and integrity of containment systems as a barrier. Recently, there has been interest in using tire chips as an additive material to prevent desiccation cracking. In this study, compaction, shrinkage, and desiccation cracking tests were performed to study the effect of tire chips on suppressing shrinkage and desiccation cracks in clayey soils. The percentages of tire chips used were 10%, 20%, and 30% by weight. The results of shrinkage tests indicate that the percentage of volume change of the specimens decreases with addition of tire chips and its value also is affected by size of the tire chips. The intensity of cracks diminishes in the clay-tire mixtures so that the observed crack reduction in the range of used tire chips content is about 40% to 80%. The optimum tire chips content also is necessary to achieve maximum crack reduction and minimum shrinkage strain, while maintaining acceptable hydraulic conductivity. This study suggests the potential application of waste tires to suppress desiccation cracks encountered in landfill clay liners. © TÜUBIITAK.
Majidabad S.S.,Bonab University |
Shandiz H.T.,Shahrood University of Technology |
Control Engineering and Applied Informatics | Year: 2015
This paper presents two novel fast converging robust controllers for Caputo derivative based fractional-order nonlinear systems. These fractional-order systems are high-relative-degree with model uncertainties and external disturbances. First, a new fractional-order model is derived from the original model based on block transformation strategy. Employing the block transformation technique makes the highrelative- degree systems versatile for sliding mode controllers design. In the second step, two different nonlinear sliding manifolds are proposed to reach a short time convergence. Subsequently, appropriate nonlinear sliding mode control laws are developed to assure the robustness and fast converging behaviors. It is worthy to notify that the mentioned sliding manifolds guarantee the fractional-order system last state convergence, and the other states convergence can be assured by control gains of the block transformation. The stability of closed-loop system for both controllers is achieved by the fractionalorder stability theorems. Finally, two comprehensive numerical simulations are carried out to indicate the superiority and effectiveness of the suggested robust controllers.
Fallah M.,Amirkabir University of Technology |
Bahrami S.H.,Amirkabir University of Technology |
Ranjbar-Mohammadi M.,Bonab University
Journal of Industrial Textiles | Year: 2016
Phytochemicals have been used over the centuries in order to cure various diseases and still do to this day. Phytochemicals are herbal extracts that are also named herbal remedies. Curcumin (CUR), which is a natural polyphenolic compound derived from the roots of the plant Curcuma Longa, has many therapeutic properties. CUR has poor water solubility and instability that has confined its further applications, thus there is need for a carrier to deliver the drug consistently. In this research, the feasibility of using polycaprolactone/gelatin nanofibers as carriers for CUR is examined. Nanofibers are obtained by electrospinning method. The morphology of nanofibers was observed by scanning electron microscopy. Fourier Transform Infrared Spectroscopy and differential scanning calorimetry is used to study the thermal behavior of the nanofibers. Antibacterial tests were conducted against methicillin-resistant staphylococcus aureus (MRSA) and extended spectrum β lactamase (ESBL). These pathogens are very dangerous and versatile pathogens emerging rapidly causing nosocomial infections in hospitals. The nanofibers were 99.9% antibacterial against MRSA and 82.56% against ESBL. The results showed that these nanofibers have potent antibacterial activity against both Gram positive and Gram negative bacteria. As a result, these nanofibers are very promising materials for antibacterial applications. © 2015, © The Author(s) 2015.
Abbasbandy S.,Imam Khomeini International University |
Hashemi M.S.,Imam Khomeini International University |
Hashemi M.S.,Bonab University
Engineering Analysis with Boundary Elements | Year: 2011
In this paper, we consider the Cauchy problem for the Laplace equation by group preserving scheme (GPS) which is an ill-posed problem, because the solution does not depend continuously on the data. For this, the Laplace equation, by using a semi-discretization method namely method of line, is converted to an ODEs system and then obtained ODEs system is considered by GPS. Stability of GPS for ill-posed Laplace equation is shown. The problem numerical results show the efficiency and power of this method. © 2011 Elsevier Ltd. All rights reserved.
Mokhtari H.,Bu - Ali Sina University |
Esmaeili F.,University of Tabriz |
Dabbagh-Yarishah J.,Bonab University
Transactions of the Indian Institute of Metals | Year: 2016
In this study, the effects of electrode clamping force on the fatigue strength of 5083-0 aluminum alloy spot-welded joints have been investigated via experimental and multiaxial fatigue analysis. To do so, three sets of the specimens—with different amounts of the sheet spacing—which have been fabricated using different values of the electrode clamping force, were selected, and then fatigue tests were performed under various cyclic longitudinal load levels. A nonlinear finite element code was used to obtain the stress and strain distribution near the roots of the nuggets as a result of longitudinal applied loads. Fatigue lives of the specimens were estimated with Crossland, Kandil–Brown–Miller, Glinka, Varvani-Farahani, Fatemi–Socie, and Smith–Watson–Topper multiaxial fatigue criteria by means of the local stress and strain distribution obtained from the finite element analysis. It was shown that, the fatigue lives of spot-welded joints were improved by increasing the electrode clamping force. Also, the comparison between experimental results and multiaxial fatigue predictions revealed that among the applied criteria, the Crossland and Glinka approaches had the best accuracy for all types of the specimens. © 2016 The Indian Institute of Metals - IIM