Sharif Digital Repository

The high production costs of pure platinum electrodes, considered the gold standard for hydrogen evolution reactions, have made the development of compositionally graded coatings a notable solution. This study focuses on the electrochemical fabrication of compositionally graded Co-Pt coatings using the potential step method, with steps at -900 mV, -645 mV, and -450 mV, each applied for 450 s. To optimize the electrolyte bath, two separate baths containing cobalt (II) sulfamate and hexachloroplatinic acid were examined: one with 0.016 M Co²⁺ and another with 10 mM Pt⁴⁺, in the presence of boric acid and sodium saccharin. The baths underwent electrochemical tests, including LSV, CV, and... 

Today, with the expansion of business relations at international levels, there are many organizations that operate in global supply chains. Activities at such levels face new types of challenges in various fields of "supply chain management" pillars, of which "supplier selection" is one of them. The possibility of unexpected events, the need to comply with environmental protection laws, as well as the need to take into account social considerations, are among the things that have increased by being in larger supply chains, making it challenging to provide the basic resources needed in such chains and forcing their managers to considering considerations other than what they have always... 

Tsunami, like many other natural disasters leaves people a short time for escape. When talking about Tsunami, the escape time is the period it takes for the wave to start moving from the epicenter, change into a giant wave gradually and reach to a cost. In order to minimize damages of this phenomenon, the escaped time has to be estimated without delay. For this purpose the first needed action is modeling the Tsunami waves. Analytical and numerical models and software that are designed based on them do exist. To have an efficient and rapid Tsunami alarming system all of these options are examined in this project. Then having a reliable model quite a few probable scenarios are propounded. The... 

In the present work, the integration of production scheduling and process control in a multi-product CSTR reactor is addressed. In order to reduce the complexity of solving this integrated problem, in the scheduling layer, a reduced closed-loop model, named scale bridging model, based on neural network concept is used. In the control layer, a neural network-based controller is used to achieve control objectives such as tracking, stability and robustness against model uncertainty. In addition, the designed closed loop system is used to obtain offline setpoint-output data set in order to train neural network based scale bridging model. In a comparative study, both simultaneous and sequential... 

When swellable elastomer are surrounded by suitable fluid, they absorb the fluid and swell. This capability is used to design different tools. For example, drug release devises, sensors and actuators, in microfluidic devises such as micro-valves and micro-mixers, and seal devises. Most of these devises are shaped cylindrically. Therefore, have a thorough knowledge about how cylindrical swellable elastomer behavior, give us a good vision about how to design such actuators. In this thesis we have used constitutive equation of such materials and have investigated behavior of cylindrical swellable elastomers analytically and numerically. Analytical investigation is focused of transient behavior... 

Knowledge was traditionally understood as a one-sided foundation for all political action and, consequently, for political power. Since the late nineteenth century, however, it has been argued that political power and action also influence knowledge—and it was even suggested that power is, in fact, the sole factor shaping knowledge. Prominent advocates of this idea, such as Michel Foucault and Friedrich Nietzsche—whose thoughts profoundly influenced Foucault—employed the method of genealogy to examine historical case studies in an attempt to substantiate this claim. Yet, a critical examination of their arguments reveals that genealogy cannot support such a universal assertion. Hence, it is... 

This dissertation accounts hydrodynamic coefficients for the hull form of Dolphine Craft using an Experimental-Numerical method. First, a short preface is mentionded about Dolphine craft and its charcterstics. Then, different methods for determining the hydrodynamic coeeficient are reviewed and the method used in this dissertation is introduced. After that, the selected methods will numerically be modeled. For accurate modeling, virtual labarotory is organizing for performing these tests During modeling, six degree freedom equation including the kinematic and Dynamics of body element are extractred and consequently, they are expressed for the rigid body and control volume of fluid. The...