Sharif Digital Repository

Octahedral crystals of Fe-Metal-organic frameworks like Fe-MIL-101, which is the most stable and active metal-organic frameworks; in combination with graphitic carbon nitride nanosheets could significantly enhance the photocatalytic activity of g-C3N4 for inorganic dye degradation under the irradiation of visible light application. This appropriate cocatalyst modifies the performance of semiconductor via suppressing the recombination of photo-induced carriers and since the synthesized composite prepared by in-situ procedure possesses close contact between each other, the migration of electrons in the photocatalytic reaction will be continued, so the degradation process via the active species... 

Immediate control of pandemic influenza to avoid casualties and financial losses is an important issue. In this thesis, two types of controllers including optimal controller and adaptive generalized predictive controller based on linear input-output model, with vaccine, treatment and quarantine being controlling variables, have been used to control influenza. Each controlling methods were investigated for different states including single-input single-output and multi-input single-output. Single-input single-output and multi-input single-output models are identified as online and offline using least squares method. Since it is difficult to exactly identify the model parameters, especially at... 

The tension leg platform is one of the compliant structures which are generally utilized for deep water oil explorations. With respect to the horizontal degrees of freedom, it behaves like a floating structure moored by vertical tethers which are pretension due to the excess buoyancy of the platform, whereas with respect to vertical degrees of freedom it is stiff and resembles a fixed structure and is not allowed to float freely. A sudden disconnection of a tendon causes a change of stiffness and unbalance of forces and moments of the total system. The objective of this study is experimental and numerical investigation on behavior of ISSC TLP. Experiments were performed in the National... 

Briefly in this thesis, these subjects have been investigated: In recent years, water is used as a solvent instead of an organic solvents have become more and more important due to cheap and environmental consideration. In this context, preparation of quinoxaline, pyrrole, new 1,4-dihydropyridine and reduction of imine to amine with 1,4-dihydropyridine derivatives as the reducing agents with the use of one-pot multicomponent reaction have been reported. The existence of several hydrogen bonding groups (NH) in the new dihydropyridines they acts as biologically active compounds in the forthcoming years. In continuation, oxidation of thiols to disulfides in the presence of NBS and NCS and... 

In this thesis, heterogenous catalysts based on magnetic nanoparticles were synthesized. In these catalysts, magnetic nanoparticles were coated with defferent fuctional groups to produce a catalyst with magnetic properties which is easily separated from the reaction medium. The structure of synthesized catalyst was characterized using techniques such as transmission electron microscopy (TEM), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and CHNS elemental analysis. Easy preparation, low cost, biodegradability and high thermal stability are advantages of these catalysts. At the end, the catalytic properties of resulted catalysts were investigated in many... 

Nanoporous metal-organic frameworks are among the new and advanced compounds that have attracted attention of researchers due to their unique properties such as high surface area, high porosity and regular structure. These compounds can catalyze and degrade pollutants. Due to the high consumption of organic compounds, especially textile dyes, the pollution caused by wastewater is increasing in various industries. Disposal of wastewater containing organic pollutants into aquatic environments can alter the natural color, change the taste of water and disturb the life of living organisms. If the dyes are left untreated in aquatic ecosystems, they can remain in the environment for a very long... 

The current thesis deals with designing of functionalized nanoporous catalysts modified with organic groups and ionic liquids and their applications for some challenging organic reactions such as synthesis of adipic acid and fatty acid esterifications. In this condition the catalysts show enhanced activity since the hydrophobicity of the surface can tune by applying organic groups. In this regard, oxidation of cyclohexene was performed using hydrogen peroxide as oxidant in the present of tungstate based task–specific ionic liquids and silica–functionalized ammonium tungstate as green catalysts. The results indicate that adipic acid achieves in high yield with excellent selectivity.... 

The purpose of this study is to prepare a catalyst for copper nanoparticles that can be used in C-H activation processes in order to increase copper salt catalytic processes by converting it into a catalyst with characteristics of having recovery cycles, convenient separation and environmental friendliness and being in nano size. Consequently, copper nanoparticles are directly grafted onto graphene oxide, or using para-aminobenzoic acid grafted on graphene oxide. A copper nanoparticle catalyst was used in the reaction to activate the C(sp2)-H bonds of benzoxazole molecule and C-N bonds formation with secendary amines. Using the results of transition electron microscopy (TEM), scanning... 

In this thesis the graphene-based magnetic nanocatalyst was synthesized. The surface of this catalyst was cavered by silica and AgNPs. In addithion of simple sepration by magnetbar, yeild of reaction was promoted by surface modification. Catalyst structure was verified by transmission electron microscopy , scanning electron microscope, fourier transform infrared spectroscopy, X-ray diffraction and Energy dispersive spectroscopy.At the end catalytic activity was examined by oxidation reaction in persense of different alcohols. The oxidation of benzylic alcohol with electron withdrawing substituents was more difficult and the yield was lower, but electron donor substituents effect positively... 

Additive manufacturing (Simply called A.M.) is a group of manufacturing technologies that is developing rapidly and is being used widely in some industries like car manufacturing, Aerospace and producing Biomedical devices, In a way that some researchers believe that A.M. methods will change the future of manufacturing. One of the most important A.M. techniques is the Selective Laser Sintering (SLS) method that is mostly used in industrial applications. A SLS machine has a lot of sub systems and mechanisms that have key role in the Laser Sintering process. One of the mechanisms of SLS machine is the Powder Dispensing mechanism that produce layers of unsintered powder as thin as 100 microns... 

In this thesis, a heterogeneous nanocatalyst based on graphene oxide was synthesized. To improve the graphene oxide, it was reacted with paraaminobenzoic acid and then metal salts (cobalt and manganese) were coated on it. The structure of the catalyst was confirmed by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), quantitative X-ray diffraction (EDS) and infrared (FT-IR) spectroscopy. Finally, the catalytic properties of the catalysts were evaluated in the oxidation reaction of different alcohols in the presence of oxygen. In the presence of benzyl alcohols with lethal electron groups, the oxidation conditions are stricter and the reaction efficiency is lower.... 

The purpose of this study is to prepare platinum nanoparticles catalysts whitch can be used to C-H activation processes. In order to increase platinum salt catalytic activity, by converting it into a catalyst with characteristics of having recovery cycles, convenient separation and environmental friendliness and being in nano size. Consequently, platinum nano particles were grafted on modified graphene oxides. Catalysts structures were verified by scanning electron microscope, fourier transform infrared spectroscopy, X-ray diffraction, and energy dispersive spectroscopy. Subsequently catalytic activity was examined for C(sp3)-H activation reaction with 3 amines and C-C bond formation. A... 

The study of maneuverability is very important in ship design. In the early stages of design, ship maneuvering is predicted with the help of mathematical models. The mathematical models used to simulate the maneuverability are relatively fast, but in this method, it is not possible to examine the exact details of the flow and the interaction between the hull and the propeller and rudder. Studying ship maneuvers in an experimental method is very accurate but also involves high costs. In recent years, with the advancement of technology, the use of computers and numerical methods has led to a good and accurate prediction of the ship's behavior during maneuverability. In this study, acceleration... 

Photocatalytic as well as photo-Fenton-like processes are promising and ideal technologies for using solar energy to regenerate energy as well as regenerate and revitalize the environment. In fact, photocatalytic processes are one of the most important chemical methods to reduce energy and environmental crises by converting endless solar energy into pure chemical potential. Photocatalytic processes and photocatalysts based on metal-organic frameworks (MOFs) have attracted special attention in recent years due to their excellent and unique properties such as adjustable structure and optical properties. In fact, metal-organic frameworks, as a group of newly emerged crystalline porous... 

It is necessary to monitor pollutants in aquatic samples, because many of these compounds can pose threats to human health and the ecosystem. Separation technology based on magnetic materials has received considerable attention in recent years. The magnetic extraction method is not only convenient, economical and highly efficient, but it also overcomes problems with conventional solid-phase extraction. In order to remove anionic dyes from single and ternary systems, zinc ferrite nanoparticle was synthesized using co-precipitation method and its surface was modified by Cetyltrimethyl ammonium bromide (CTAB) cationic surfactant. Surface characteristics of ZFN-CTAB was studied using Fourier... 

During the recent years, shortage of drinking water is one of the concerns of the society and necessity of purification of contaminated water are taken into consideration. Different methods to be developed to prevent problematic pollutions. Among these different methods the most common one is adsorption. In this thesis, the copper oxide nanoparticle was synthesized and its surface was modified using N-(2-aminoethyl)-3-(trimethoxysilyl)propylamine. The bi-amino surface functionalized nanoparticle was used to remove anionic dyes from single and binary systems. The scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Energy-dispersive X-ray spectroscopy (EDAX)... 

Azo dyes that are the most common dyes in textile industries, are toxic and stable complex compounds. Release of this dyes in environment disturb the ecosystem and endanger human health. So selection of an appropriate method for treatment of them is a sensitive work. photocatalytic degradation is one of the best promising methods because of its perfect mineralization, middle condition and lack of creating the secondary pollutant. In this research CuO/CNT nanocomposite was synthesized and used as a photocatalyst. The surface features of CuO/CNT were surveyed by using Fourier transform infrared(FTIR), X-ray diffraction (XRD) and Scanning electron microscopy (SEM). Photocatalytic efficiency of... 

Environmental issues and lack of drinking water had forced researchers to find some alternatives in order to wastewater treatment. Since dyes are used in a variety of industrial application such as textile, pharmaceutical, etc.; therefore, wastewater of these factories makes several environmental problems. Using catalysis under UV- irradiation (photocatalysis) is one of the cases that is used in wastewater treatment which the catalyst stimulated under UV- irradiation and this process degraded dyes. In this work, reactive red 198 degradation is investigated with MIL-53(Fe) and MIL-100(Fe) and in the literature section, the methods that was implemented by other researchers is studied.... 

This thesis is divided into two parts: In part I, which is theoretical part, we were looking for a computational method which is extensively comparable with experimental results to determine pKa of wide variety of organic compounds. The pKa is an important property in many sciences such as chemistry, biology, and material science, since inclination of a compound to donate or accept a proton is fundamental to understanding many chemical and biochemical processes. Experimentally determined pKa values are not always available from literature sources and often estimated values are employed in their place. It is useful, therefore, to have reliable and accurate means of calculating relative and/or...