Sharif Digital Repository

Man’s struggle for optimization in different areas has been an endless one. Optimizing methods of cancer treatment is not an exception. Because of numerous side effects of anti-cancer drugs, drug delivery systems (DDS) have been recently given much interest. Considering some aspects, DDS are helpful in reducing harmful effects of anti-cancer drugs and more efficient healing by these drugs: first by reducing the dosage of drug by controllable and sustainable release of drug in a kinetic (diffusion) pattern; second by smart release of drug in target tissue which in turn protects sound tissues not to be in contact with drug.In this study, three kinds of nanoparticles have been used for DDS... 

One of the major problems in cancer treatment is side effects of treatments. Today, scientists have developed smart nanocarrier for diagnosis and drug delivery that can circulate in the bloodstream, pass the body's immune system to kill cancer cells and attach to the cancer cells to deliver drugs, without the side effects that are in other treatments, such as chemotherapy. magnetic nanoparticles coated by biodegradable polymers are one of the smart polymers. In this study, iron oxide nanoparticles with amine group on their surface are coated by starch modified by methyl acrylate then reacted with hydrazine and hydrazide functional group is formed that can chemically be bonded with the... 

Dye-sensitized solar cells (DSCs) are third generation of solar cells, which composed of a porous layer of wide band gap semiconductor such as TiO2, covered with a molecular dye that absorbs sunlight, and a counter electrode contacted by a liquid redox electrolyte. Photovoltaic performance is the collective measure of light harvesting, charge separation and charge collection efficiencies. Light harvesting has a significant role in improvement of photovoltaic performance. Molecular engineering of dyes to improve absorption spectrum or to have a broad absorption spectrum,andlight scattering layes are approaches for this porpuse. This research is focused on photon management in DSCs using... 

This project presents an outline of the crack tip stress fields in the presence of a plastic enclave around a growing fatigue crack using RKPM and Drucker-Prager criterion for pressure sensitive materials such as concrete and rock. Two distinguished features of RKPM are the arbitrarily high order smoothness and the interpolation property of the shape function which has kronecker delta property at the associated nodes. This method has proved to handle extreme material deformation and moving discontinuities. For the frictional materials such as rock in geotechnical engineering, a non-associated or associated Drucker- Prager plasticity model is appropriate for modeling its constitutive... 

Dye sensitized solar cells (DSCs) are among the 3rd generation solar cells which their mechanism of light absorption is similar to chlorophyll in green leafs and is based on photo-excitation of dyes. The electron-hole pairs of photo-excited dye separate at the interface of mesoporous semiconductor-dye-electrolyte. One of the approaches to increase the light path length and therefore the light harvesting efficiency in DSC is the addition of light scatterers inside the mesoporous semiconductor (photoanode).In this research, nanoparticulated hollow TiO2 fibers are introduced as novel light scatterers in DSCs with simultaneous light scattering, light trapping and high surface area. Light... 

Dye Sensitized Solar cell (DSC) is the third class of solar cell, which consists of a nanocrystalline, mesoporous of semiconductor(The best one is Tio2), covered with a monolayer of dye molecules, platinum coated on FTO as a counter electrode and a redox electrolyte. This Photovoltaic cell which is promising low-cost materials, works on electron separation of dye molecule, and electron injection to semiconductor’s conduction photo- electrode structure and its porosity is affected the DSC’s performance. Recently, use of electrophoretic deposition (EPD) for TiO2 electrode (which best found for photo-electrode in DSC) fabrication has gained increased interests. In this method charged particles... 

In this work, a comprehensive dynamic model has been used for vinyl acetate emulsion polymerization in a continuous reactor to predict the evolution of product particle size distribution under isothermal condition. Method of finite-volume has been applied for solving the population balance equations and the results are compared with the results obtained from moment method. Finite-volume method has been selected as a precise technique to predict sustained oscillations, which occurs in continuous emulsion polymerization. After performing sensitivity analysis and verification of system’s controllability, feed rate of surfactant and initiator have been selected as proper manipulated variables to... 

In this work, a comprehensive dynamic model has been used for styrene emulsion polymerization in a semi-batch reactor to predict the evolution of product particle size and molecular weight distributions under non-isothermal condition. Method of moments has been applied for solving the population balance equations and the results are compared with the results obtained from finite-volume method as a precise technique. A sensitivity analysis respect to perturbation in initial values of various reagents, species and the reactor temperature has been performed to identify suitable manipulated variables for closed-loop control of the reactor. The detailed model is used to generate optimal feed... 

Productivity is a widespread context that has been considered in several levels and different sights. Improving productivity has comprehensive effects on economic principal, social and politic phenomenon of society like decreasing inflation, increasing welfare levels, increasing preoccupation levels and political contest potency . In this research the non-parametric output-oriented Malmquist DEA method has been used. Malmquist TFP index method has a major advantage, by allowing the decomposition of TFP growth into efficiency change and technical change. In this research Malmquist index has been calculated for 33 generating' companies, 16 transmission' companies and 37 distributing'... 

In this study reliability and sensitivity analysis of the parameters of a concrete gravity dam have been proposed regarding to their probabilistic behavior. At first, the uncertainty of concrete fracture energy (GF), Foundation’s elasticity modulus (E_f), and the Peak ground acceleration (PGA) are considered according to their probability density function (pdf). The uncertainty sources are inserted in the model using the Latin Hyper Cube Sampling method (LHS) in order to do reliability analysis of the model. Monte Carlo method is one of the most popular methods for reliability analysis of numerical models. Taking this method in uncertainty analysis would evaluate the effects of the inputs on... 

The objective of this thesis is to prioritize a portfolio of buildings for seismic retrofit. A new set of sensitivity measures is proposed to rank the buildings in accordance with the reduction in the loss of the entire portfolio. To this end, various risk measures are differentiated with respect to the cost of retrofit for each building. These risk measures are the moments of the portfolio cost probability distribution which imply the risk-neutral and risk-averse decision making. Two costs are considered: Construction cost due to retrofit and repair cost due to structural and non-structural damage. To quantify the risk, reliability methods are employed in which many interacting... 

Damage and collapse in structural systems due to structural loads are considered as a threat to human lives. Therefore, using structural health monitoring methods in order to estimate structural damages and preventing structural collapse, have drawn a lot of attention. Due to the importance of considering random vibration, a nondestructive damage detection method using power spectral density function has presented in this study. This method is based on model updating and solving the sensitivity equations and it is also a model based method. The mentioned method can be classified as a vibration-based health monitoring method in frequency domain which includes dynamic excitation in some... 

Groundwater quality protection has a significant importance due to abundant applications of these resources in various fields such as agriculture, industry and drinking water. Removal of groundwater pollution is a time and money consuming process and often pollution is detected when improving the quality of groundwater is nearly impossible. For this vulnerability assessment there are three methods: Processing, Overlap-Index and Statistical Methods. Overlap-Index is composed of variety of maps such as Geology, Soil, Groundwater Depth and etc which uses in determining of vulnerability Index. In the present study for underground pollution potential determining, four indexes such as AVI، GOD،... 

Recently lots of studies have been done on driving cycles and parameters affecting pollutants emission and fuel consumption. Due to changes of driving behavior and traffic situations, it’s necessary to update driving cycle of a city to obtain more accurate simulation and analysis results. In this project, first of all driving cycle of Tehran city is developed using three different methods. These methods include choosing representative microtrips from specified traffic situations, clustering and choosing representative microtrips from all available data. Results show that using clustering method is more accuarate and parameters of the cycle developed using this method is closer to measured... 

Dye-sensitized solar cells were introduced by M. Gratzel in 1991. These solar cells have a power conversion efficiency of about 12% over the AM1.5 full sun. Traditionally, a liquid electrolyte redox system is used to regenerate the dye. Due to stability issues, a solid hole transport material has been employed to replace the liquid electrolyte as an attempt to create solid-state Dye-sensitized solar cell (ssDSC). Over past few years power conversion efficiency of ssDSCs has improved considerably and reached over 7%.
Here, ss-DSCs based on TiO2 nanoparticles as photoelctrode and P3HT as hole transport material were fabricated and characterized. We used three different methods; dip... 

In this thesis, photocatalytic oxidation as a potential method for the treatment of organic environmental contaminants is deeply investigated. While the photocatalytic degradation of various organic compounds under UV light irradiation has been widely investigated, visible-light-induced photocatalytic degradation of low-levels of the pollutants such as Dibenzothiophene (DBT) and 2-Nitrophenol (2-NP) are occasionally reported. In the present work, Lanthanide / Polyethylene glycol -modified TiO2 (La/PEG/TiO2) and Fe,Cu,S/TiO2 have been successfully synthesized by a sol–gel method. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission... 

Dye-sensitized solar cells (DSSCs) are emerging as low-cost alternatives to conventional, solid-state, silicon solar cells. A porous network of a nanosize semiconductor material with a wide band-gaps usually TiO2, serves as charge transport medium. A monolayer of dye is chemically adsorbed on this material. Photoexcitation of dye causes injection of electrons into the conduction band of TiO2 from where they diffuse towards a transparent conducting oxide (TCO) substrate. The dye is regenerated through receiving electrons from a redox couple dissolved in the electrolyte. After passing through a desired load, the electrons enter the cell through a counter electrode to reduce the redox ions and... 

This paper presents some approaches based on data mining techniques to solve the prediction task of Computational Intelligence and Learning (CoIL) Challenge 2000. The prediction task of the contest is a direct mailing problem and the goal is to improve its response rate. The main issue in this competition is the incompatibility of the dataset in which the distribution of the classes of the target attribute is highly unbalanced. This in turn causes high error rate in identifying the minority class samples. Three different level methods including data-level, algorithm-level, and hybrid method are used to overcome this issue. The specificity and sensitivity criteria are employed to compare the... 

In the present study, TiO2-reduced graphene oxide (T-RGO) nanocomposites were synthesized via various in-situ and ex-situ methods, then their photovoltaic performance was examined as photoanode and mesoporous layers in dye-sensitized Solar Cells (DSSCs) and perovskite Solar Cells (PSCs), respectively. Graphene oxide (GO) was prepared using Hummer’s method with some modifications. Both thermal and hydrothermal processes were used to reduce GO. Structural and optical characterization was analytically demonstrated by subjecting of the obtained materials by several techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, thermogravimetric analysis (TGA),... 

Safety of concrete gravity dams under dynamic loading that cause from earthquakes is an important aspect of research.as we know, dam structure response is related to type of loading, properties of concrete and foundation material, so according to the uncertainties of these random variables, in this research we calculate the response (stresses) of structure for different value of random variables that have their own probability distribution type. Nonlinear plasticity damage model of dam is implemented in ABAQUS and for reliability analysis we use Latin Hypercube Sampling (LHS). Sensitivity results show that PGA of earthquake and Special Energy (Gf) of concrete in comparison with concrete...