Sharif Digital Repository

Microbiologically Influenced Corrosion (MIC) of concrete sewer ptpes and wastewater collection systems has been reported in many places of the world. Recently, numerous copper compounds have been used for bacterial growth control in sewer pipes. In this thesis, bath parameterswere optimized in order to maximize copper osmosis to the porous concrete matrix.Concrete pipes were electrochemically coated inCopper Lactate bath in a constant current mode (1=0.6 A), while temperature was set to 25, 50, 75 and 95
°Cand pH to 9,10 and 11. Specimens were then characterized by scanning electron

microscopy, optical microscopy, XRD andAAS. Copper Osmosis was highest in pH=9 and... 

The purpose of this research is to provide a method for finding a “good” solution to the network design problem with less computational efforts, faster than the existing conventional methods of solving this problem. Network design problem is the problem of selecting a subset of projects from a set of alternative projects so that to optimize the objective function (e.g., the total travel time in the network) subject to the set of existing constraints (e.g., budget). Due to the combinatorial and non-convex nature of the problem, its solution could be very cumbersome and time-consuming. Various methods have been proposed to solve this problem efficiently, providing good solutions at high... 

Epilepsy is one of the diseases that affects the quality of life of epileptic patients. Epileptic patients lose control during epileptic seizures and are more likely to face problems. Designing and creating a seizure detection system can reduce casualties from epileptic attacks. In this study, we present an automatic method that reduces the artifact from the raw signals, and then classifies the seizure and non-seizure epochs. At all stages, it is assumed that no information is available about the patient and this detection is made only based on the information of other patients. The data from this study were recorded in Temple Hospital and the recording conditions were not controlled, so... 

HCCI engines have lower NOX and PM emissions and higher thermal efficiency compared to spark ignition engines. But these engines have some deficiencies which up to now have prevented their widespread employment. These engines have not been very successful at high loads and speeds and in these conditions normally produce high pollution and noise. In order to solve this problem the present research proposes to equip the HCCI engines with fuel injection system so that at low loads and speeds operate at HCCI engine mode and at loads and speeds higher than pre-set limits, use the fuel injection system in order to operate at a combined HCCI and compression ignition engine mode and provide a... 

Many studies on hybrid vehicles have been done in the past few years. The Full hybrid vehicles need a large number of batteries creating up to 300V to meet the required voltage of electric motor. The size and weight of the batteries cause some problems. This research investigates the mild hybrid vehicle. This vehicle includes a small electric motor and a high power internal combustion engine. In most cases the car’s driving force is created by internal combustion part. A small electric motor, which can operate as engine starter, generator and traction motor, is located between the engine and automatically shifted multi-gear transmission (gearbox). The clutch is used to disconnect the gearbox... 

Some researches have been carried out in the last 20 years in order to increase the present IC engines thermal efficiency and their optimum performance. (HCCI) engine is viewed as a combination of spark-ignition (SI) and compression-ignition (CI) engines. This is because HCCI engines use premixed fuel/air mixture like SI engines and have auto ignition combustion after the mixture is compressed like CI engines. Control of combustion and ignition timing are the main challenges of these engines. Ignition delay, compression ratio, fuel air equivalence ratio and intake temperature and pressure are considered to be the most effective parameters on HCCI combustion.HCCI engines have great potentials... 

The partially stratified charge (PSC) approach involves micro-direct-injection of pure fuel or a fuel air mixture, to create a rich zone in the region around the spark plug. A theoretical model is presented in this research to predict ignition delay and combustion process in partially stratified charge engine. It considers flame progress through rich and lean regions. Step by step calculations will be carried out in both regions. The process continues to the point where all the fuel is burned. At each step for one degree rotation of the crank shaft, there is a change in cylinder volume and mole fraction burned due to burning of a fraction of the mixture. Considering heat transfer from the... 

In many countries of the world, especially dry and semi-arid areas, coastal aquifers are used to provide fresh water. Many of these areas have also become urbanaized, which has made the need for freshwater more important. Seawater Intrusion (SWI) is the greatest limitation that influences the exploitation of groundwater in coastal aquifers, where with SWI, the amount of freshwater supply and other existing pumping wells are not used. The present study attempts to model SWI in karst and fractured coastal aquifers. For this purpose, two models with Discrete Fracture/Conduit Network approach in Fortran and also in COMSOL Multiphysics software have been developed to study the density-variable... 

Hydrogen is one of the favorite substitute for fossil fuels due to various properties including the flammability, ubiquity, and easy extraction from plain water. These properties have made it an appropriate alternative source of energy that can be used in internal combustion engines. Compared with fossil fuel energy, in addition to much lower emissions, hydrogen has proved to be much more efficient when applied as a clean source of energy. The main purpose of the present project is to study the effect of applying hydrogen on performance of compression - ignition as internal combustion engines as an alternative fuel. These studies encompass the results derived from the experiment of using...