Sharif Digital Repository

Boric acid (H3BO3) is a weak monobasic acid that exist as a white powder in the standard conditions. In industry, it is used in manufacturing of fiberglas filaments, precious metals soldering and production of flat panel LCD displays. In all of these applications, normal grade boric acid is used, but nuclear industry demands an ultrapure boric acid (UPA) for controlling of the reactivity and power levels in pressurized water reactors. Annual consumption of UPA in Bushehr Power Plant (BPP) is around 60 metric tons. Currently, this amount is imported from Russia, but atomic energy organization of Iran plans to displace it by the acid made inside the country. Domestic production of UPA in... 

Let G be a simple graph. A harmonious coloring of G is a proper vertex coloring such that each pair of colors appears together on at most one edge. The harmonious chromatic number, h(G), is the least number of colors in such a coloring. In this project, first we discuss about complexity of harmonious coloring. Then we find some bounds for harmonious chromatic number  

This investigative study intends to identify and characterize bitumen from seven Iranian bitumen production plants according to the Superpave Performance Grading (PG) system, conventional classic tests, and chemical separation tests. The study then compares the identified performance grades with the thirteen performance-grade binders required for specific climatic zones in Iran. It is observed that the variety of available binders is not adequate to fully cover the required PGs. Blending was initially considered as a suitable and economic method for production of the missing performance grades. However due to similar rheological properties of bitumen samples, resulting in nearly identical... 

Expansion of communication and the emergence of new fields such as the Internet of Things, has led to the development of smart cars and especially self-driving cars. The antennas used in the radar of these cars are of special importance for a better understanding of the environment around the car. The important parameters for the design of antennae for automotive radar are: good resolution, narrow beam width, the ability to change the angle of the main beam, etc. Among the most common antennas used in these radars are directional antennas, for this reason phased array antennas and leaky wave antennas are suitable options for this application. In general, the complexity and difficulty in the... 

Providing low-power fault tolerance is usually an important requirement in real-time embedded systems. A faulty result in safety-critical systems and a failure to meet a deadline in hard real-time systems can cause catastrophic consequences for the system or environment. Therefore, these systems must be highly reliable and meet real-time constraints. Slack time in time redundancy techniques (e.g. roll-back recovery) can be used to increase system reliability and to save energy. Time redundancy techniques are suitable from an energy consumption point of view but may not be sufficiently reliable for tight real-time constraints. In the condition of tight timing constraints, the hardware... 

The purpose of this project is the prediction of the activation barriers and enthalpy for elementary steps in the process of Fischer-Tropsch over the surfaces of Fe, Cu and Fe/Cu alloys catalyst by using of UBI-QEP method aiming at finding prediction of the activity and selectivity on the basis of energy criteria.
UBI-QEP methods is based on conservation of bond index of adsorbed molecules and follow the quadratic exponential potential for energy, calculate the enthalpy and activation barriers of reaction pathways in a heterogeneous catalytic process and select the most desirable path to take.
The elementary steps such as dissociation of CO, hydrogenation of carbidic carbon, C-C... 

In this thesis, the improving effects of deposited metal oxides onto or next to each other and the advantages of every metal oxide were considered. In the next step, the substrate improvement was studied and the porous metal oxides with ideal supercapacitive properties with porosity increase of substrate were obtained.CoFeO2 supercapacitor was prepared by chronoamperometric ethod.CoFeO2waselectrodeposited at room temperature and presents wide potential window and good capacitive properties in comparison with other metal oxides.Layers of cobalt and manganese oxides were co-deposited or deposited on top of each other or next to each other by chronometric method onto stainless steel substrate.... 

In this study, electrochemical oxygen reduction reaction (ORR) was studied on Cu, Pd, Rh, Pd-Cu and Rh-Cu alloys in alkaline solution. Pd-Cu and Rh-Cu alloys were prepared by electrochemical methods. On copper electrode it is found that direct oxygen reduction is accompanied by the electrochemical reductions of copper oxides. Also, mechanism and kinetics of reaction change as the amount of copper oxides increase on the surface. For electrodeposited alloys, it is indicated that the reactivity of Pd-Cu and Rh-Cu alloys toward oxygen reduction is higher than pure Pd and pure Rh. The maximum reactivity among Pd-Cu alloys is related to the sample with 24.5% copper content while the maximum... 

This work investigates adsorption and possible dissociation of a number of small molecules on small clusters and carbonic surface. Theoretical study of carbon monoxide adsorption on SixGe4_x(x=0–4) nano-clusters has been carried out using MPW1B95 density functional. The geometry, adsorption energy, charge distribution, and vibrational frequency of CO adsorption on all possible structures were investigated. The maximum vibrational frequency changes occur in the bridge structures while the most stable structures occur when CO adsorbs on one silicon atom in a flat surface. Adsorption energies of CO on one Si atom are by far more negative than the corresponding value for on Ge atom. Theoretical... 

The aim of this project is to investigate the mechanisms of absorption and reactions of H2, O2, HCO2H on the single crystal surfaces of transition metals alloys such as Ni-Cu and Ni-Fe and …as well as the ability to control the properties of the mentioned alloys with change in constitutions percentage. In order to achieve the objectives, Unity Bond Index-Quadratic Exponential Potential, UBI-QEP method have been employed. Using this method, the thermodynamic parameters (heat of adsorption and reaction enthalpy changes) and kinetic parameters (activation energy of the reaction) can be calculated, and using these results, intermediate, and as a result, the mechanism of heterogeneous catalytic... 

In this thesis, the improving effects of TiO2 nanotubes (TiO2NTs) fabricated by anodizing of titanium as suitable substrate for deposition active materiales in supercapacitors were considered. PANI/Pd/TiO2NTs electrodes with highly porous structures and good capacitive characteristics were prepared by electrodeposition of polyaniline on palladium nanoparticles loaded TiO2 nanotubes. The results illustrated that the specific capacitance of these electrodes was around 1060 Fg−1 in 1.0 M H2SO4 electrolyte as measured at a constant current of 2.0 Ag−1, whereas it was 210 Fg−1 for the PANI/TiO2NTs electrode. NiO-ZnO/TiO2NTs electrodes were synthesized by the electrodeposition of... 

In Li batteries, lithium ions are exchanged between two electrodes, along with the accompaning electron transfer to maintain riability good ionic conductivities and electrolytes stability are achived through additives to the electrolyte. Such matrial should possess good anions acceptability. This work investigates the potential of aza-ethers in this regard. The softness criteris is basically employed. DFT calculation for selected molecules of different size, substituents and interacting atoms are used to correlate softness, electrophilicity, Fukui no, etc to the usefulness of the corresponding matrials  

Network design is one of the major strategic decisions of a supply chain which leads to the whole sustainability of the chain. Besides, due to an increase in carbon dioxide emissions and its harmful effects, recently there has been an growing interest in green supply chain network design. In this thesis, a mixed integer linear programming is developed to formulate a closed-loop supply chain with forward and reverse logistics. Moreover, social cost rate of carbon dioxide is used to consider environmental impact. Considering uncertainty in closed-loop supply chains is crucial. To do so, three robust optimization methods including Soyster, Ben-tal and Nemirovski and Bertsimas and Sim approaches... 

Public projects are those projects that are run by public financial resources such as tax or other national governmental incomes. Selection of these projects is relatively difficult due to their importance, long life-time, and high costs. In most models developed in previous studies to select public projects, financial matters and risks are the only factors which were considered. However, the public projects should naturally be selected in a way that citizens’ benefits are maximized (in both short- and long-term) and citizens’ living level increases. In other words, public projects should be selected to increase citizens’ satisfaction. In this thesis, a model for public projects is presented... 

Reliability Centered maintenance (RCM) is a systematic approach for designing preventive maintenance program for plants. Quality Function Deployment (QFD), which is a well known tool of Total Quality Management, is also a systematic and disciplined approach for designing products and services. In QFD the objective is to satisfy the requirements of the customers of the product or service with limited resources. Now if we consider the preventive maintenance program that RCM specifies for a plant as a service and define the customer requirements for this service to be preserving the functions of the plant we can use QFD for maintenance via RCM. By doing this all the proven advantages of QFD... 

The train scheduling problem is one of the most important scheduling problems in the transportation systems. The goal of train scheduling problem is generating a feasible timetable which consists of train departure times and determining the best station to stop. Optimizing the railway capacity is one of the most important goals in train scheduling phase. The sequence of dispatching trains and stopping schedule are the main factors that can affect railway capacity on double track lines. In this thesis, a double-track train sequencing problem is studied in order to maximize the railway capacity, subject to a set of operational requirements. This research proposes a flexible flow shop... 

Nowadays, NGOs have a special roll in solving social problems in the world. In regards to the developing state of these organizations in Iran, the need of adopting a systematic approach in managing these organizations, is bold. Renewing of the old methods of work in these organizations, is an aid to removing the barriers of development faced by these organizations.
In this regard, this thesis subjects the reengineering of business processes of Rayehe Charity Foundation which is an NGO dealing with empowerment of households women.
After studding the literature of reengineering, the thesis continues on introducing the organization and its activities in more detail. It categorizes... 

In this work, Unity Bond Index-Quadratic Exponential Potential (UBI-QEP) method was applied to investigate the decomposition routs of -halo alcohols on Ni(111) and Cu(111) crystallographic planes and Ni2Cu1(111) and Ni1Cu2(111) alloys. UBI-QEP calculates energetics, H and E, along reactions routes using heats of atomic adsorption as empirical inputs and in this way avoids needs to be very specific about every system. The results of analysis of -halo-propanols on Ni and Cu surfaces are in good agreement with experimental findings; namely in the formation of carbon-monoxide, ethylene, water and hydrogen over Ni and propene and water over Cu. Predicted activity of -halo-propanols,... 

According to a novel approach of National Petrochemical Company to deployment of quality concepts on petrochemical projects and effort to develop the excellence models & paragons in various fields like managing contractors of petrochemical project and plans, “Project Based Organizations Excellence Model” presented by Project Management Research and Development Center of National Petrochemical Company as a new pattern of performance improvement in this companies. Implementation of this model in organization also required many infrastructures as knowledge and wisdom, managerial concept, dynamic and process vision that appear gradually. The purpose of this thesis is the development and also...