Sharif Digital Repository

For the sake of decrease in energy and force of earthquake, seismic isolators are used. Regular seismic isolators are too heavy and damaged by chemical materials, therefore in this research a new approach is used that steel shim plates replaced by carbon and polyamide fibers. The aim of this research is to obtain the dynamic and mechanical properties of carbon and polyamide fiber reinforced isolators in comparison with steel reinforced isolators. In this approach, firstly some specimens have been designed and manufactured, then compresional and cyclic shear tests were carried out on them. All three type isolators are cylindrical and have identical diameter and height. The steel, carbon fiber... 

It has been about a decade that cosmological datas have shown the universe is accelerating. To describe this acceleration, cosmologosts use cosmological constant as the easiest way to describe,or the modified gravity models or smooth dark energy models as other ways. In this thesis we solved a specific structure formation problem, density contrast, for linear structures, in two different methods. the first method was LCDM model and the second method was a specific f (R) gravity model. We shpwed that these two solutions are about the same.
 

In the modern world of software engineering, software evaluation has earned a special position. The presence of consultation companies in evaluating the software will confirm this specialty. Web technology, as a new trend in computer science, has attracted the attention of many researchers and practitioners. As known nowadays, most of the software solutions are Web-based. Such software is technically called Web application. The methods of evaluating Web application include the use of traditional metrics in software engineering. The intelligence of the Web in computer science has been the core of much research.
This study is intended to use intelligence, as one of the new features of the... 

A survey on the methods of detecting a human body inside surrounding captured images of a machine, optimizing one of these methods and finding an injured person in a captured picture is our target. Using neural networks for better detection and making RBFN network, make it possible to use high altitude captured pictures with lower resolution and light changes. Modifying RBFN to MRBFN network for an optimized processing with effect of living signs seems to be an applicable approach. These methods can extended from detecting an injured person in a captured picture, to analyze the medical images like detecting a special pattern in MRI picture. Of course it’s a start for many future... 

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... 

Mesoscopic hydrodynamic equations are solved employing a VOF based method to investigate the equilibrium shape of nanodroplets positioned over various topographic geometries of the supporting substrate for three-dimensional systems. By taking into account liquid-liquid and liquid-solid interactions a complex distribution for inter-molecular forces over the substrates (the disjoining pressure) is observed. In this research we show that motion of nanodroplets not only caused by contact angle difference in drplets two sides, but also depend on disjoining pressure parameters.Geometries with increasing complexities, from wedges to three dimensional edges and wedges, were explored with the main... 

Observations made after previous earthquakes have shown the crucial role of irregularities in initiating damage in buildings with irregularity, either in Plan or in Elevation. Since in existing Building Codes, there is no provision for the distribution of the Equivalent Static Loads for such buildings, designers have no option but to resort to Dynamic Analysis. In this work, the seismic behaviour of a group of two-dimensional steel building structures with irregularity in elevation, namely Split-Level buildings, was studied. The studied structures consist of a series of 5- and 15-storey frames having two parts with splitting distance of 150 cm. Both, moment-resisting and braced frames were...