Sharif Digital Repository

Ni-SiC composite coatings are widely used in industry (equipment high wear resistance coatings, corrosion resistant coatings, ship and boiler coatings, . . . ). Its unique properties in high wear resistance, corrosion resistance and tribological properties, researchers tend to investigate this coating. This study covers Ni-SiC composite coating under pulsed current using a rotating disk electrode to achieve optimal conditions in synthsis process, increaseing hardness and resistance to corrosion in coatings.waats' bath established for electrodeposition in this research. Bath parameters, current parameters and hydrodynamic of solution is examined. Changing of current type from direct current... 

In the past, lead-based solders with homogeneous and isotropic behavior were used in microelectronic packages. But today, due to the environmental concerns of lead, lead-free solders have been developed, which consist of a high weight percentage (more than 90%) of tin. Tin crystal shows significant anisotropic behavior, which leads to an anisotropic joint response in miniature solder joints with a small number of grains. In the first part of this research, using the crystal plasticity model, the anisotropic plastic response of tin grain was extracted from bulk solder stress-strain curve, then it was implemented in Abaqus software using built-in Hill's anisotropic plasticity model to consider... 

Computer Aided Diagnosis (CAD) systems are widely used in different medical tasks. Radiology is a branch of medicine which takes advantage of image processing techniques to help radiologists, analyse complicated radiologic images. Among all kind of medical imagingprocedures, utilization of screening mammographyisgetting very popularin detection of breast abnormalities. A typical CAD system for mammogram analysis uses image enhancement and segmentation as pre-processing phase, and feature extraction and classification for detection phase. In this thesis, we have studied different approaches in each level of image processing required in a mammogram mass classification systems, and introduced a... 

Having adequate information about water and weather condition is critical for many areas of governance, specially in the context of increasing rates of climate change and uncertainty related to different weather conditions. Open water data and data dissemintation decision making in Iran is facing many challenges, while the number of users and variety of services based on these data and information is increasing. Based on the review of the documents in this study, the most problems that have been reported for developed countries in the field of collecting, processing and using these data and information are the technical challenges related to the large volume of raw data and the need for... 

Because of the importance of the issue of poverty, in this study, we introduce and copute aspects & dimensions of multidimensional poverty index. The object of this thesis is studing the trend of changes in Iranian households’ welfare during the years 2005 through 2015 and recognizing the economic and social poor households’ characteristics. There are two methods that are used to computing MPI (Multidimensional Poverty Index). One of them is standard method that is given unique weight to each dimension, the other one is questionnaire method which is asked poverty experts to set proper weight to each dimension. Knowing how poverty index (income & mpi) changes, can help policy makers to... 

In this study formation of a single bubble on fluidized bed distributor is investigated. Digital image processing and pressure sensors are used to analyze bubble characteristics. Effects of density and the size of particles on bubble diameter, formation time, separation and passing velocity was studied in different flow rates of nozzle. Bubble diameter when is separated from nozzle was greater for lower density particles which have the same size. The ratio of diameter formation was approximately equal to inverse of densities ratio. Bubble formation time is decreased by increasing the flow rate of nozzle and the formation time is approached to a specified value. In addition, it was observed... 

The objective of this project is to study the behaviour and performance of an innotative floating offshore platform. Such Platform not only can be used for exploring oil from offshore fields, but for creating artificial islands, where land is in short supply. Due to its specific and, at the same time, simple geometry (symmetric), its fabrication does ont involve much complexity. Studies carried out on this platform include the investigation into its structural behaviour under gravitational (including self weight) and bouyancy forces. Studied cases include a number of platforms with different (geometrical) sizes and under 3 various bouyancy conditions (percentage), namely 1) 50% of the height... 

Fire is one the events which threatens the very existence of every building, residential, office, industrial or else. However, this threat is more serious with regard to buildings with steel structures. Steel, despite its many advantages over other structural materials, such as having high strength to weight ratio, ductility, toughness and resilience, has the disadvantage of rapidly losing its strength at elevated temperatures, i.e. in fire. Therefore, it is the responsibility of the designer to make the serious decision of whether to use steel, concrete, timber, or other materials for the structure of the building to be designed. Observations made during full-scale fire tests as well as... 

Due to unusual response of structures of buildings with irregularity in their architecture to dynamic excitations, to have a comprehensive knowledge of their behavior during earthquakes is of utmost importance. Building irregularities are in general divided into two major categories, namely Irregularity in Plane and Irregularity in Elevation, and one of the forms of the latter is where there is a split in the levels of the building. In this work, through a series of case studies, the effects of P- phenomenon on the behavior of steel split-level building structures were studied. 5, 10 and 15 story buildings with 5 and 6 bays, and level splitting of 30, 60, 90, 120 and 150 cm were studied. All...