Sharif Digital Repository

Today safety is one of the major competition factors in automotive industries . The vehicles of today are more and more dependent on electronic systems , for driving safety and ease on control for the driver . Some systems are more or less standard in vehicles on the market , examples of such systems are ABS , ABC , etc. Despite of the effect of these systems on vehicle dynamics ,because they only control longitudinal dynamics and don't receive any feedback from vehicle lateral behavior , now control systems ,named VDC , have been developed and implemented in advanced vehicles. The operation of such systems is as this that in any time instance they evaluate vehicle dynamical behavior.... 

Construction is a large industry in Iran, it engages in a wide range of products. The raw materials which are used in making a building are fairly standard items: iron, cement, glass, and so on. Because the technologies for making a building are well-known, contractor can solicit bids from variety suppliers for raw materials without worrying about the possible disclosure of trade secrets. Unfortunately bidding processing in Iran becomes very slow and inefficient. Each transaction required to request the relevant telephone number to supplier that might be interested in bidding on the item, it would often take purchasing personnel more than one week to gather the information, send it to... 

Despite eye-catching progressive trends in highway safety, there have been a great number of unpleasant incidents in highways. A number of 8841 people died in road accidents in the first 6 month this year with 1.7% increase compared to the accidents occurred in 1396 [59]. Operation of a modeling process shall provide the engineers with more opportunities to identify the affecting factors in roads incidents. Safety infrastructure management is mainly aimed at ensuring the efficient measurement, systematic recognition and consequently deterioration of road accidents when they have been designed, constructed and used [37]. Building information modeling (BIM) tends to be a developed managerial... 

The application of ultra-high performance concrete (UHPC) as an alternative to conventional/ normal concrete (NC) has grown rapidly in recent years. However, there is limited knowledge on its shear behavior, which is essential for developing design guidelines for structural applications. A detailed parametric study was conducted on 38 beam specimens, half of which were made of UHPC and the other half made of NC. To ensure applicability of findings, two types of UHPC mixes were used, a proprietary and a generic mix. Eighteen of the beams were prepared and tested in Tabriz, Iran, while the other 20 were made and tested in Miami, FL. Test parameters included type of concrete (UHPC and NC),... 

Vehicular Ad hoc Network (VANET) is a subclass of Mobile Ad hoc Network (MANET), which provides us ability to communicate between moving vehicles. VANET has been developed as a standard means of communication for Intelligent Transport Systems (ITS) to improve traffic safety and efficiency while providing internet access on the move. Congestion control is a challenging subject in VANETs primarily due to the shared nature of the wireless channel and frequent changes of the network topology. Inefficient congestion control causes periodical safety messages to be lost and introduces latency in threat modelling at the application layer. There are two methods to overcome this problem. First, based... 

This thesis presents an inventory control system which is based on Meta-heuristic Algorithms.In this thesis we will optimize the input values of our tree-echelon inventory model (keeping costs,stock worth,reorder costs,...) with these Algorithms. The presented method is able to determine the optimal stock level, costs of system and number of shipments in the system. The method is basically a decision support system (DES) and it is able to provide the order scheduling parameters of goods at operational level. The aim of the current research is to demonstrate that a Meta-heuristic algorithmis capable of solving complex inventory problems and with future improvements it is able to achieve... 

Competitive world of industrial production need more speed and faster reaction for the customer needs. This should be carried out in low cost activities while satisfying what the consumers and customers require. Business of commercial refrigerators and freezers is a big industry targeting small to big customers. In this thesis a systematic method relying on reduction of cost, reworking and unexpected expenditures in product life is utilized. Stands for Design for Manufacturing, DFM is a series of principles and guideline simply to achieve a faultless design of a product so that the non-incurred costs of the product travel through its life cycle become minimized. Freezers and refrigerators... 

In nuclear power plants, the fission reaction takes place inside the fuel rods, and the heat generated inside the fuel rods is transferred through the clad wall to the cooling fluid, which is single-phase, subcooled and in the turbulence zone. In the hot channel of the reactor core, where the axial and radial heat flux reaches its maximum state, the fluid leaves the single-phase state and some steam is formed in the area close to the clad wall.Therefore, in some cases, in the hot channel, the steam near the clad wall may reach a point that reduces the heat transfer coefficient, rapidly increases the wall temperature and thus destroys or melts the sheath surface. If this happens, it means... 

operation of a nuclear power plant. Therefore, constant monitoring of the reactor core with reliable methods is important. To monitor the reactor heart, it is necessary to estimate and calculate some parameters, with high speed and accuracy, such as power distribution inside the heart, reactivity feedback coefficients, PPF, DNBR, etc. Analytical methods are often used to calculate these parameters, which in case of failure of the sensors, the calculations will be practically disrupted, and the method used in this research can solve these problems by losing a small amount of accuracy.In this study using real data of Bushehr nuclear power plant (BNPP) and by soft computing methods and... 

In this work, we aim to find a way to identify and forecast transients in nuclear power plants with the aid of semi-supervised machine learning algorithm. Forecasting and identifying transients in nuclear power plants at the early stages of formation are essential for safety considerations and precautionary measures. The use of machine learning algorithms provides an intelligent control mechanism that, along with the main operator of the power plant, raises the transient detection and identification rate. Our algorithm of choice is to change the way data is presented, which is a semi-supervised learning approach. The algorithm consists of two methods: quantum dynamics clustering... 

In this study, the determination of the distribution and the differences concentration of hydrogen in containment of Bushehr power plant by modeling of containment and Hydrogen removal system of Bushehr power plant during LB-LOCA accident is accomplished. In Bushehr nuclear power plant, which has a unique design, the containment is similar to PWR power plants with a metal sphere, but the installed reactor is a VVER-1000. After a full study on the containment and its systems, the required data for modeling is gathered and afterwards, the engineering handbook is prepared for MELCOR input code and then the modeling and size classification of the containment is done in 4 different ways,... 

Transfer of Spent Nuclear Fuel from reactor building to storage facilities is one of the most important operations at Front End of Nuclear Fuel Cycle. The aim of this project is to calculate the risk of the radioactive materials release into the environment during various stages of spent fuel transfer operations. In addition, the contribution of each of the initiating events in total release probability were also determined. For this purpose, Probabilistic Risk Assessment method which is usually used in safety evaluation of the nuclear facilities, is applied. The main tools used in this method are event tree and fault tree. In this study, SAPHIRE software has been used to construct the event... 

Because of the Complexity in Calculating the Probability of Failure of the System, This Computation is Done by the Software Have Been Developed for this Purpose. Of Course, When We Use Them, We See That Each of Them Have Their Advantages and Disadvantages. One of the disadvantages that have been tried to be resolved over time, the type of programming and algorithm for calculation of it is the fault tree Because new techniques like modularization which have been designed in recent years, a significant improvement in accuracy and speed performance computing applications that use this method have been obtained.In This Thesis Has Developed Software That is Able to Calculate the Probability of... 

Inadvertent opening safety valve of pressurizer (SVP) is one of the most common initiator events in Booshehr nuclear reactors with occurrence frequency of 1.1E-0.2. This event has the third rank in initiator event among 16 other events (Loop and Compensated LOCA were ranked as first and second respectively). So special attention must be paid to SVP and the operators need to have specific trainings on this matter. In this thesis, the SVP as initiator event is being considered and the sequence which lead to core damage (CD), according to design informations is being modeled moreover the qualitative and quantitative analysis is carried out. In the modeling process we have used the SAPHIRE... 

In this study the modeling of Bushehr power plant containment is considered. In Bushehr atomic power plant, which has a unique design, the containment is similar to PWR power plants with a metal sphere, but the installed reactor is a VVER-1000. After a full study on the containment and its systems, the required date for modeling is gathered and afterwards, the engineering handbook is prepared for MELCOR input code and then the modeling and size classification of the containment is done in 4 different ways, including the control volumes of 1, 9, 23 and 30 and then the temperature, pressure and density of hydrogen is examined. The result of studying control volume sensitivity reveals that 23... 

In the absence of appropriate control, several accidents in the nuclear power, lead to serious consequences including core melted and radiation leakage outside reactor containment. In all these events, when core melted, the reactor operation is always finished and all efforts are then directed to environmental impacts of radioactive materials to the external environment. However, the occurrence of events that would bypass reactor containment, have special significance, because all possible efforts in order to limit the leakage of radioactive materials to the external environment are ineffective. In this respect the occurrence of such incidents, as most of which is considered the worst... 

Using of physical safety devices such as pressure safety valves, are the most conventional methods to protect vessels against overpressure but operation of these devices have many negative effect on environment also they waste significant amount of valuable hydrocarbon materials. Relying on conventional safety devices needs a flare net to send excess gas to torch and in many cases essential equipments for flare net is so expensive and their maintenance are difficult thus reducing the size of flare net for a chemical plant is beneficial.
Application of new alternative device (HIPPS) is very helpful to reduce flaring load and releasing pollutant materials such as SOx and NOx. The main... 

The HIPS is a safety integrity system that is designed to provide overpressure protection that is at least equivalent in reliability to a mechanical relief device. In this study, the performance evaluation of HIPS in Assaluyeh gas Refiner is studied.In the first stage, over pressure analysis is compiled using dynamic simulation and API RP 520 and the recommended HPPS design procedure is presented. Also, The High Integrity Protection Systems (HIPS) further reduced the relief load and even eliminated the relief from the stabilizer tower for the scenarios tested.In this project, following a detailed study of the commissioning process and its criticalities, Hazop is selected as the most suitable... 

In this study, the thermal-hydraulic analysis of prismatic HTGR’s core with natural convection has been studied using porous media approach. VHTR are the new generation reactors which due to special neutron and thermo physical properties have highly inherent safety. In lose of forced circulation accident, decay heat is transferred from core to pressure vessel wall and then to water tubes in concrete wall at reactor cavity with conduction, convection and radiation automatically. In this case the high volume of decay heat is stored in graphite block with high thermal capacity and is prevented the instantaneous temperature rising.
The aim of this study is justifying inherent safety of HTGR... 

In general, release of hazardous gas in chemical process plants could be due to two reasons. First is failures due to degradation of components that have inventory of hazardous gas in standard process conditions, and the second is deviation of system from standard process conditions because of different failure modes of related components, e.g. controller equipments. The purpose of this study is, calculating the probability of H2S releasing in GS(03) plant of Arak Heavy Water factory, using PSA methods and its risk assessment. At First, fifteen groups of initiating events were identified with Hazop study for desired system. Then, for calculating the frequency of each event, the combination...