Sharif Digital Repository

Fast growing load in power systems associated with a large gap between heavy load and light load periods, generation scheduling and unit commitment (UC) problem has become a crucial issue in Scheduling time horizon. In a vertically integrated power system, unit commitment determines when to start-up or shut-down units and how to dispatch online generators over a given scheduling horizon in order to minimize the operating costs. Therefore main objective of this thesis is selected as unit commitment considering ramp rate, emission and line flow constraints. In this thesis four main works has been done: at first generation scheduling considering next hour is done which may yield to increase... 

Different molybdenum oxide nano/micro structure thin films were synthesized by thermal evaporation method under various growth conditions such as deposition time, temperature and evaporation source-substrate distance. Molybdenum oxide nanostructures grown on Si(100) such as nanowalls, nanostars and nanowires were characterized with scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM). Shape and type of nanostructures were determined with SEM, AFM and HRTEM analysis. XPS analysis showed that the synthesized nanostructures contained Mo6+, Mo5+, Mo4+ and... 

Concentrations of air pollutants emitted by motor vehicles in traffic tunnels, due to low access of tunnels to Open space increases rapidly. Increasing the tunnel pollutant concentration, decreases tunnel air quality level which is very dangerous for human health. Thus study of traffic tunnel air pollution concentration and dispersion is important for offering control strategies in these spaces. This investigation has been tried to study vehicular pollutants emission and dispersion inside traffic tunnel by data collection that involves traffic, meteorology and air pollutants characteristics in a urban tunnel. So data collection was carried out in the Resalat tunnel located in urban... 

Recent stringent HC and CO emission regulations are because of increasing consciousness of the perilous influences of exhaust emissions. The chief attempt to pass the standards is to decrease the emissions during cold-start, due to catalytic converters are not efficient until they arrive a light-off temperature. It has been discovered that 50% to 80% of the controlled HC and CO emissions are sent out from tailpipe of automotive during the cold-start. Therefore, in order to minimize the cold-start emissions and fast light-off of catalytic converters, it is important to understand the catalytic converter characteristics and techniques for rapid warm-up catalyst. This thesis describes a... 

In this thesis, possibility and advanteges of dynamic descent route assignment during busy traffics and implementing changes within navigation infrastructure is examined. Facilitating Continuous Descent Approaches (CDA) as optimum descent paths is the main goal of this research. One advantage of this project with respect to previous works in this field is dynamic CDA routing between cruise altitude and Terminal Radar Approach Control (TRACON) entry to meet the demand of traffic during peak hours.The other superiority is proposition of LASER technology as an alternative/backup NAVAID system in order to facilitate the latter.Terminal area of Hartsfield-Jackson international airport with real... 

Recently, nickel oxide nanostructures with NaCl-type structure have a variety of applications due to excellent chemical stability, as well as optical, electrical and magnetic properties. In this research, first by using DC and RF sputtering methods,nickel thin films were deposited on Si (100) and glass lame substrates under different experimental conditions (Discharge power, pressure and growth time).The deposited layers were annealed in air at different temperatures to obtain and compare their crystalline structures. Nickel oxide nanostructures grown on the Si (100) were studied by scanning electron microscopy analysis (SEM) to determines surface morphology, atomic force microscopy (AFM)... 

In this study, nano-powders of copper-cobalt spinel (CuCo2O4) were fabricated by solution combustion synthesis (SCS) of Cu and Co nitrates with urea, glycine,acid citric and alanine. The method involved exothermic decomposition of viscous liquid nitrates and the fuel. Products which were synthesized by using this fuels contained less impurity constituents. Duo to low purity, other factors which have influence on synthesis process investigated and observed that pH have key role on process. X-ray diffraction (XRD) patterns gave crystal structure and the existing phases. Particle size distribution and morphology changes were studied by dynamic light scattering (DLS) and field emission scanning... 

Mobile Sources are the main source of air pollutant emission in Tehran, the capital city of Iran. Everyday thousands of vehicles commute in roads and highways. Unfortunately, People are exposed to high level of particulate matter and gaseous contaminants in automobile cabins. Even though this environment is exposed to high pollutant concentration emitted by on-road vehicle, In comparison with other built environment, in-cabin commuter exposure and its key parameters has never been quantified. In general, this work entails measurement of in-cabin air quality, predicting mathematical models for calculating Air-Exchange-Rate (AER) in vehicles and on-road vehicle emission measurement. Our... 

To estimate vehicle fuel consumption and emissions in Tehran mega city, air pollution in urban tunnels, parkings, determination of speed limits on highways and produce required inputs of softwares that forecast dispersion and distribution of air pollution, Hot exhaust emissions model of Iranian manufactured gasoline fueled personal cars of Tehran developed. Emission factors is the most important element of model, that obtained from portable emission measurement of 30 vehicles with suitable type and mileage distribution. By averaging the results, total emission factors and fuel consumption of fleet designated, used to annual estimation. in addition with curve fit to data, emission functions... 

Nowadays, due to various reasons awareness of environment preservation has increased throughout the supply chain. So supply chain owners revise their carbon footprint. Among different methods of reducing, operational decisions (e.g. ordering quantity or transportation method) has less cost and time for observing outcomes. Our main focus is on inventory models that taking account environment considerations especially carbon emissions. Through these models, vendor-managed inventory model for reducing total cost of chain gets more attention than past. The purpose of this work is to develop a two echelon supply chain with multi-item for replacing inventory. This model includes warehouse capacity... 

Small animal SPECT imaging systems have a broad application in developing new diagnostic or therapeutic radiopharmaceutical and biomedical researches. The main goal of this imaging method is to determine distribution tendency and amount of radio pharmaceutics in body. In this study we have developed a reconstruction technique along with photon attenuation correction so as to obtain a high quality image and the finding a relationship between image matrix and absorbed radioisotope in tissues in order to quantify SPECT images with acceptable error range. In this research we have used MLEM method for image reconstruction and the obtained images were evaluated from quantitative and qualitative... 

In This article, we aimed to estimate impact of dual sourcing strategy on environmental implication and show how this strategy can ameliorate the emission of greenhouse gases. For this purpose, first we define comprehensive NLP models for splitting order problem with carbon emission cap and carbon emission Trade-Cap policy. Then customized sequential quadratic programming approach had been developed for solving these models. In addition, customized Genetic Algorithm validated this approach. Finally numerical results show that order splitting strategy cause to reduction in costs and emission at same time. Beside this outcome, we show the so-called Trade- Cap policy almost performs better than... 

In this study, a new multi-scale hierarchical technique has been employed to investigate the role of edge dislocation on nano-plates with hex atomic structure in large deformation. Two multiscale hierarchical atomistic/molecular dynamics (MD)–finite element (FE) coupling methods are proposed to illustrate the influence of temperature on mechanical properties of Magnesium in large deformation. The atomic nonlinear elastic parameters are obtained via computing second-order derivative of Representative atom’s energy and RVE’s strain energy density with respect to deformation criterions (deformation gradient and Green strain tensor) to bridge between atomistic and continuum level, the... 

In the present work, the effect of different methods of melting, remelting and solidification conditions on the microstructural evolution of IN100 superalloy was investigated. For this purpose, the superalloy was solidified within steel and ceramic molds to provide different cooling rates. Furthermore, the re-melting processes using ESR in the water circulated copper mold and ceramic molds, VAR and combined ESR and VAR were considered. The microstructure of alloy under different casting and remelting conditions were studied by means of optical and SEM microscopy and ESD analysis. According to our results, the ingot which was cast in the ceramic molds, due to lower cooling rate during... 

The need for integration of electron guns together with thermal considerations of thermionic cathodes has led to design new cold cathode guns based on field emission phenomenon. In first part of this thesis, basic field emission theories, fabrication methods of field emitter arrays, effect of different parameters on the field emission properties of field emitter arrays and applications of these arrays are investigated. After setting up fabrication methods of nano-tip field emitters, in the second part of thesis, Si nano-tips and Si field emitter arrays are fabricated using of thermal oxidation of silicon substrate, lithography, and chemical etching of silicon oxide and silicon substrate. Si... 

For policy and decision makers, controlling pollution emissions are a real challenge. The best way to collect fiscal resources, optimal distribution of them to developing businesses in optimal energy production and reducing emissions, are important issues to be decided. Finding a monetary value emissions imposing to community is a key point to find out how they are affecting the whole economy and this will help decision makers to conduct better road maps and policies. Many different approaches and methodologies are used in literature to find appropriate answers to above mentioned questions and phenomena, in this research, integrated assessment modeling methodology is used, an economical... 

The iron and steel industry has faced several challenges during the recent years. There has always been an aspiration towards higher economic profitability for the system. During the mid 1970s and 1980s the energy crises caused a dramatic rise in energy costs, which led to an increased awareness in energy conservation. In recent years, climate change issues have become more important for the industry. The operating practices for an industrial system are often affected by external restrictions concerning the economical, energy and environmental efficiency of the system. There are a large number of ways to increase the system efficiency, e.g. installation of new process equipment, and practice... 

Direct injection spark ignition lean burn engine with stratified mixture is concerned recently and research and development are in its initial stage. In this thesis, at first a thermodynamic simulation of these engines was done for investigating of stratified mixture effects on combustion characterization and compare it with homogeneous one. In this modeling we use from turbulent flame speed model for mass burning rate analysis, multizone model for exact measuring of temperature distribution, full chemical kinetic model for emission concentrations and some proposed mixture formation for predicting of stratified mixture. The results shown that stratification is caused to improve combustion... 

Reducing air pollutant emissions from vehicles is a difficult and time consuming procedure which needs utilizing of modern emission control equipment and setting strict regulations for car factories and drivers as well. How efficient these policies are and proposing operative solutions for air quality improvement depend on developing a sustainable model which is used in vehicle emission predictions and their share in total emissions. Emission factors are not constant values as they can be affected by various operational and ambient parameters. Development of Emission inventories calls for a huge number of measurements using different vehicles in diverse conditions. Thus, recognition of... 

When increased emissions are combined with a carbon tax or emissions trading system, the result is a supply chain with increased costs attributable to the emission generated on the different parts of supply chain. Most traditional supply chain design models do not take emissions and carbon costs into account. Hence, there is a need to incorporate emission costs into a supply chain optimization model to see how the optimal supply chain configuration may be affected by the additional expenses. This thesis presents a mathematical programming model for the design of green supply chains. The costs of carbon dioxide equivalent emissions were incorporated in the objective function, along with the...