Sharif Digital Repository

Ni-P alloy coatings were electrodeposited using pulse current in a watt type bath in various conditions. The influences of different parameters were investigated and optimized for the highest amount of coating hardness using the Design Of Experiment (DOE) method. The optimized deposition parameters were current density 23.7 A/dm2, duty cycle 75%, frequency equal to 188 Hz, temperature equal to 70ºC and 17.5 gr/l of H3PO3. The DOE prediction of hardness for the optimized coatings was between 700 and 750 the achieved micro-hardness was about 725.8 HV. It was obtained that an increase of the current density will improve micro-hardness, decreases P content and increase deposition rate. Also, the... 

The aim of the present research project has been techno-economical analysis of using a CCHP (Combined Cooling Heating and Power) technology at the building of Sharif Energy Research Institute (SERI). The CCHP at SERI is supposed to supply energy required at the building. Useful energy demand at the building include heating in winter, cooling and air conditioning in summer, lighting and power requirement of electric appliance and equipments. Since there are many technologies that could be utilized as CCHP, an optimal model of energy supply system of the building has been developed in order to identify the most appropriate technology. The application of model has enabled techno logical... 

Nowadays, oil has an important role in our life and most of its role can be seen on the transportation. Discovering and extraction of oil are very important to produce oil and receive it to costumer. When oil is discovered, the oil companies used to drill the ground to extract the oil but they can’t extract all of oil from its reservoir. So, researchers proposed to inject another fluid like water to the oil reservoir to extract oil. Oil is trapped in the porous media which has a lot of pores and some of them have a micro scale size and they contain oil. When water is injected to the reservoir it flows in this pore and interfaces with oil and they create a multiphase flow. The governing... 

In this paper, a hierarchical RVE-based continuum-atomistic multiscale framework is established on the basis of the nonlinear finite element method and molecular dynamics simulation in order to model the geometric and material nonlinearities of deformable solids. In this framework, the coarse scale material properties required for nonlinear finite element method are directly exploited via fine scale atomistic simulation of atomic RVEs designated for each coarse scale integration point and required boundary conditions for atomic RVE simulation are achieved from the coarse scale kinematical response. In order to ensure the kinematical and energetic consistency between the two scales, the... 

Planing hulls have been under rapid development during recent years and their maximum speed has increased significantly thanks to advancements in high power engines and light weight hull construction methods. In the past two decades, the main concern have been hydrodynamic characteristics and stability of the planing hulls in straight-line motion in calm and rough water, and no applied mathematical model is proposed for their dynamic motions in different maneuvers in contrast to displacement hulls. Moreover, control loss at high speeds is very prevalent and in most cases this leads to economy and human losses. The main target of this thesis is to develop and validate a mathematical model to...