Sharif Digital Repository

Around 20 to 50 percent of the operation costs occurs in manufacturing is related to facility layout. Efficient design would reduce these costs by 10 to 30 percent. Facility layout consists of design of material handling system and plant layout. Design of material handling system includes determining, the flow network and locations of Pick-up and Delivery stations which are defined regarding to the kind of material handling equipment. Today, Automated Guided Vehicles are considered as the basic material handling equipment due to their potentials in production planning and controls, high safety and flexibility and low expenses.
In this thesis, we first discuss the design of the shortest... 

The material handling cost is a significant portion of the operational costs in a production system. Designing an efficient material transport network helps reduce these costs. In most unequal-area facility layout models, the total loaded trip distances are minimized, and the empty flows are overlooked. In these models, it is assumed that the transportation of load is possible through bidirectional rectilinear paths connecting pairs of departments, and the optimal location of departments is determined based on the rectilinear centroid-to-centroid distances. These assumptions lead to a complex network with a large number of edges, which is impractical to implement in reality. In this study, a... 

In this thesis, bayesian network has been used in analyzing the failure of a structural component. The design life of a structural component of a system can be limited or unlimited depending on the working conditions considered by the designers. However, usually during the operation of an industrial system or device, a structural component of it fails prematurely, in other words, its actual life is less than the design life. In this case, the failure must be analyzed to find the causes and factors. The method of work is such that first, according to the problem and the type of failure, the required analyzes and studies are considered. Then, a number of samples of the components, whose... 

A Cylinder Liner is one of the most important functional parts that gives a wear protective surface of cylinder block for piston and piston rings. Liners are used in automotive, ships, power aircrafts, and power generation units and the most load carrying part in internal combustion engine. Liners are subjected to various stresses during the engine working status. The stresses which act on cylinder liner are stress due to action of gas pressure and heat. Result of that stresses, wear developed inside of liner and internal or external cracking of cylinder liner takes place. In this paper, complete thermo-mechanical analysis of cylinder liner and failure mechanisms detected in alloyed cast... 

In this Thesis ,the two-dimensional thermoelastic tractive rolling contact problem for an FGM coated half-plane under the plane strain deformation is investigated. A rigid cylinder rolls on the surface of an FGM coated half-plane with constant translational velocity, generating frictional heat in the slip zones of the contact area. Thermo-mechanical properties of the FGM vary exponentially along the thickness. It is assumed that the contact area consists of a central stick zone and two slip zones of the same sign. The transfer matrix method and Fourier integral transform technique are used to achieve a system of two Cauchy singular integral equations. The associated governing equations are... 

The main factor ensuring safety of passing maneuvers on two lane highways is known as Passing Sight Distance (PSD). The criteria presented in Iran's code and AASHTO Green book are provided by the results of researches conducted between years 1938 & 1941 in the United States. This research intends to find out whether some changes should be applied to the PSD criteria according to current vehicles' performance and driving behavior in Iran. For this purpose, about 8 hours of video films has been recorded from 3 different sites chosen from two-lane highways in Iran, resulted in 326 passing records. In the case of passing of two passenger cars The models provided by analyzing the videos show that... 

Frontage roads are widely used to separate the main and the local traffic flows in multilane highways. Based on the studies conducted by Texas Transportation Institute, the delay imposed by ramp junction is considered for calculating the average speed in frontage roads in addition to the control delay caused by traffic lights. This delay and the capacity of frontage roads are analysed using gap acceptance theory. In this study, two different sections consisting of a basic section and merge area are selected along Tehran-Karaj special road as case studies and the required data are collected by video recording. After classifying and analysing the data, a wide range of macro traffic-analyses... 

Incidents are one of the main sources of delays and they have significant influences on road safety and congestions, air pollution and trip costs. In the time of an incident occurrence, minimizing the response time is essential for several reasons. The most important issue is providing aid for the injured. The faster the persons who are severely injured receive aid, the higher their chances are to be rescued. Also, if the rescue crews get to the incident scene faster the clearance procedure would be accomplished faster and this would result in fewer disturbances in traffic stream and lowering the probability of secondary incidents occurrence. Automatic Incident Detection, AID, has been... 

One of the methods that have been used in order to mitigate the air pollution problem is the IM program in order to identify the high polluting vehicle and make them to adjust their engine in accordance to the emission standards. In Iran due to the air pollution problems the government operates a rudimentary IM program based on the idle engine test utilizing an exhaust gas analyzer which should be done annually. While IM programs usually regarded as a useful tool for soothing the air pollution, one of the criticisms about the program is that it is required for the entire fleet and it reduces the cost effectiveness of the program. This research studies the relationship between the vehicular... 

In railway transportation network, there are spots that we have to intersect with highway network. These intersections break into two branches named grade crossing and unlevel crossing depend on their structure. Grade crossings from the view of protection are grouped into protected crossings and unprotected crossings. Protected crossings depend on their traffic control devices are categorized into active crossings and passive crossings.There are many factors that influence highway-railroad grade crossing design. Some of these factors can vary widely by drivers' behavior. These factors have been developed in models by AASHTO and its publications and shaped like we have them today. In order to...