Sharif Digital Repository

Local scour around bridge piers is one of the main causes of bridge failures Application of existing equations to complex flow patterns is problematic and often leads to questionable results in the field applications. A lack of understanding of the complex flow field and erosion mechanisms seems to be at least partly responsible for this state. Despite the rapid expansion of the literature on the flow around cylindrical piers, there are still challenges for flow field comprehension and estimating design scour depths around complex bridge piers. Due to geotechnical and economical reasons, bridge designs often leads to a complex foundation. Laboratory studies of local scour around complex... 

Numerical simulations and large eddy simulations (LES) of turbulent flow around single pile, circular tandem piles, circular and square side-by-side piles at different spacing ratios (centre to centre distance to the pile diameter) with flow Reynolds number of 105 on the fixed flat-bed are presented. The calculations are performed using a computational fluid dynamics model, FLOW-3D, which solves the Navier-Stokes equations in three dimensions with finite volume method. Numerical simulations are validated by comparing the numerical results of time-averaged flow patterns around single and side-by-side piles with that of the experimental measurements. At the downstream of single pile,... 

The development of a complex software needs an abstraction mechanism which is called Model Driven Engineering mechanism. In order to have a successful model based process, we need an appropriate tool such as version control systems to support our model-based process. On the other hand, developers need a mechanism to synchronize them with VCS systems. One of the concerns in modeling languages is the compatibility and the consistency of the models and modeling languages during their evaluation. the focus of the former researches was mostly on the consistency of the models during their evaluation, and to this end, lots of approaches have been proposed for keeping the consistency of the models... 

Nowadays economical issues are greatly taken into consideration. In this project we aim to study a problem of this area, which focuses on the subject of location allocation and pricing strategy for a good supplier. Solution evaluation is done by taking costumer demand into account. This problem has a sequential characteristic. That is players do not take their decisions at the same time. Suppliers should first decide about where and how they plan to provide their goods. On the other hand almost every economical problem have multiple players who play with or against each other. Therefore modeling this problem using Stackelberg leadership model is a natural choice. Since this problem is in the... 

Preventive maintenance strategies have been considered by highway agencies in order to increase pavement service life and to reduce the costs associated with pavement maintenance. Due to the increasing concern regarding promoting sustainable pavements, consideration of the environmental, economic and performance factors in devising preventive maintenance strategies is of great importance.This study contributes to developing a multicriteria decision-making tool for sustainability evaluation of pavement preventive maintenance strategies. The developed tool, PaveSAT, considers the greenhouse gas emission, net present value, and pavement performance to rank preventive maintenance schemes using... 

The attention to ice accretion subject and its implementation have recently become very serious in our country due to a substantial need to a further understanding of this phenomenon and improving the design and construction of anti-ice systems for the airplanes in-hand. The subject of this study is the numerical simulation of ice accretion at the surface of airplanes, which is a technical approach in aerospace engineering. In other words, this study simulates the details of ice growth at different sections of an airplane wing considering wide ranges of different affecting parameters and conditions. To achieve this, we numerically solve the governing equations for two-phase flow of air and... 

The main purpose of this Thesis is to study logistics situation of L90 production site at Iran khodro Co. and improving it to achieve the project and investment goals. Some proposals in the fields of plant layout redesign, inbound logistics, material flow analysis, and Kanban and synchrony systems development are offered. Plant layout optimization based on allowing facilities parting into more than one section is studied and its mathematical model is developed. A heuristic alogorithm for this type of FLP’s has been offered which optimizes a given solution. The propsed methodology is applied on a real case-Iran khdro L90 site and the obtained solution indicates good results of the algorithm.... 

The rapid growth of information on the web and the need for information sharing on one hand and also as news plays an important role in our life and internet becomes the biggest repository for keeping this news on the other hand, lead us to research in this domain.
In this thesis, we introduce a new framework for searching news by considering the relation between news and events. This framework called NewsSe. NewsSe considers news as a series of events in order to cover all aspects of news. NewsSe uses Domain Ontology and Event Ontology to extract the concepts and relations existed in news. NewsSe consists of 4 different modules. NewsCr is a crawler which uses a new methodology for... 

Right now, the common standard for programming of CNC machines is ISO6983 which is also called G-code. This standard provides very low level information that only contains information about basic measurements and tool movements. Moreover, it splits the CAD/CAM/CNC chain and makes it difficult to gather feedback from shop floor. A global attempt led to development of a new data model for programming CNC machines. STEP-NC standard which is developing based on STEP is aimed to resolve shortages of G-code. The STEP-NC based controllers, can be categorized into three major groups in terms of programming: indirect, interpreted and adaptable. In this project, in order to develop the third category...