Sharif Digital Repository

A multi-agent system is a system consisting of several intelligent agents. In fact, a multi-agent system is a system that includes a large number of agents that communicate with each other through message transmission in a network structure. Multi-agent systems can solve problems that are difficult or impossible for a single agent or an integrated system to solve. Blockchain is an example of these multi-agent systems that has many use cases in different fields for example cryptocurrencies . A blockchain is a growing ledger consisting of records called blocks. In this thesis, we want to provide tools for the simulation of this multi-agent system so that we can model the issues surrounding... 

Today because of increasing use of fuel, environmental problems and problems due to heavy structures in different industries it is important to use structures with high specific strength. Using different materials in structures like polymers accompanying aluminum could be useful. Polymers are light, heat insulating and have a high corrosion resistance. Polypropylene is one of the useful polymers which can have high impact energy and strength via adding Elastomer and Talc powder, relatively. One of the common ways in joining metal to polymer uses adhesive. It has variety of benefits such as low distortion in joining, different materials joints and having joints with complex geometry. Welding... 

In this study, water-stable metal-organic frameworks, UiO-66-(CO2H)2, MIL-53-NH2 (Al), ZIF-8 and MIP-202 (Zr), were selected to study the influence of using plant extracts in drug loading process and also its targeted release from these compounds. For this purpose, at first the solution of different plant extracts was used separately as a synthetic solvent in the preparation of the desired MOFs to be present in the structure of these compounds and increase the interaction of the drug with the nanocarrier. Then, a coating of plant extract was applied on the nanocarrier containing the drug after loading the drug to prevent the rapid penetration of the drug from the cavities of MOFs (drug... 

The advent of nanopore-based sensors based on resitive pulse sensing gave rise to a remarkable breakthrough in the detection and characterization of nanoscale species. The sensors can detect the species’concentration, size, and charge using the resistive pulse characteristics. Some strong correlations have been reported between the resitive pulse characteristics and the particle’s geometrical and physical properties. These correlations are commonly used to obtain information about the particles in commercial devices and research setups. The correlations, however, do not consider the simultaneous effect of influential factors such as particle shape, charge, and off-axis translocation, which... 

In this research, the effect of changing the synthesis parameter of the anion with the central metal, the effect of different hydrothermal and reflux synthesis methods, as well as the effect of reaction time on the properties of the Metal-Organic framework (such as morphology, crystallinity, pore size and volume) of ZnPMA (PMA: 1, 2, 4, 5-benzenetetra carboxylic acid) was investigated. for this purpose, firstly the desired Metal-Organic Frameworks were prepared by interacting the 1, 2, 4, 5-benzenetetracarboxylic acid linker with the metal ion Zn2+ obtained from the metal salts Zn(OAC)2, ZnCl2, Zn(NO3)2 and ZnSO4 under reflux and hydrothermal conditions. also to investigate the effect of... 

Joining metal and alloy is a continuous and inevitable effort in oil and gas and automotive industry, and a considerable number of these joints are dissimilar joints. Steels and aluminum alloys are two of the most utilized engineering material and bi-metallic steel-aluminum parts have a lot of applications due to having the combined properties of both alloys (for example the high tensile strength and wear resistance of steels along with good thermal and electrical conductivity and corrosion resistance of aluminum alloys). However, fusion welding of aluminum to steel possesses great challenges due to the difference in melting point, coefficient of thermal expansion, thermal conductivity and... 

The Internet of Things is one of those concepts that, while it has gained significant importance in recent years in scientific and industrial communities, still faces various challenges, such as power consumption and scalability. In networks powered by batteries, it is necessary to optimize power consumption to extend the network's lifespan to the maximum possible extent. Additionally, considering the large number of connected devices in the Internet of Things network, it is essential to optimize the number of devices connected per gateway, ultimately reducing the need for fewer gateways in a network. In this research, we utilized simulation-based methods to extract output parameters of a... 

A new class of design has been introduced in the RF circuits and Frequency Synthesizers, which is based on the digital circuits. Implementation of the digital synthesizers suppresses the need to use loop filter and thus reduces the loop lock time. In this thesis different topologies of digitally controlled oscillators using inductor and capacitor tank and all digital architectures used in high frequency all digital synthesizers in 0.18um CMOS technology has been inspected and simulated. Novel techniques introduced to improve the ring oscillator-based design’s specifications which doesn’t need inductor. Using the introduced techniques, the phase noise has been lessened acceptably with respect... 

In this project two manganese(III) complexes with 2-(2',4'-dihydroxyphenyl)-2-oxazoline ligand, [Mn(4-OHphox)3], [Mn(4-OHphox)2(CH3OH)2]ClO4 and a copper(II) complex with 2-(2'-hydroxy)-2-oxazoline ligand have been synthesized. The complexes and the ligands were characterized by elemental analysis (CHN), FT-IR and 1HNMR spectroscopies. Oxidation of sulfides catalyzed by these complexes using urea-hydrogen peroxide (UHP) as oxidant within short reaction times (5 min) was investigated. The results showed that catalytic efficiency of [Mn(4-OHphox)3] complex was better than other complexes. Optimization of the catalyst system presented a high selectivity of sulfoxide (90-100%) in a few time (5... 

Ruthenium complexes with their wide range of stable but chemically accessible oxidation states have been extensively studied as catalyst of hydrocarbon oxidation. In recent years, these complexes with various ligands have been reported as new catalysts with better selectivity and several co-oxidations. Ruthenium complexes act as oxidation catalyst, often via ruthenium-oxo species as active intermediates in the oxygen transfer process, oxidizing alcohols or alkanes and epoxidizing alkane. Here, we reported the synthesis and catalytic activity of a ruthenium(III) complex with bidentate oxazine ligand. The new synthesized Ru(III)-oxazine complex was characterized by IR and UV-Vis spectra and... 

In recent years, application of transition metal biphasic catalytic systems for different reactions is an area of intense research activity. Among these reactions, oxidation of sulfides to sulfoxides and sulfones due to their importance as an intermediate in synthesis of organic compounds is a center of interest. Also, the catalytic conversion of alcohols to the corresponding aldehydes or ketones is a fundamental transformation in both laboratory and industrial synthetic chemistry. From environmental perspectives, the development of new catalytic oxidation systems with molecular oxygen as green oxidant is particularly attractive. In recent years, ionic liquids have been extensively studied... 

Petroleum contains a large variety of metal compounds with vanadium and nickel being the major metals. Some 6–34% of the total vanadium content is made up out of metallo-oxo-porphyrins, also referred to as petroporphyrins. Metalloporphyrins have long excited interest as oxidation and epoxidation catalysts. In the other hand the selective oxidation of sulfides to sulfoxides is of interest because of the importance of sulfoxides as synthetic intermediates in organic synthesis. A range of sulfides can be selectively oxidized to the corresponding sulfoxides in good yields using catalytic quantities of vanadyl complexes. Vanadium oxo tetraphenylporphyrin VO(TPP) catalyst is successfully applied... 

In this study new manganese(III) complexes of phox [Mn(phox)2(MeOH)2](ClO4), (phox= 2-(2` hydroxyphenyl)-5,6-dihydro-1,3-oxazine) have been synthesized and characterized with CHN,NMR and IR.The six-membered bidentate (N,O) oxazine ligand have been widely used throughout organometallic and inorganic chemistry, and are particularly important in homogeneous catalysis. The presence of N and O donor sites in oxazines may modify significantly the ligand roles for the variation of steric and electronic properties. Therefore, such systems are worth exploring for new catalytic uses . Catalytic oxidation reactions provide excellent alternatives for the use of stoichiometric reagents like urea... 

In this thesis, ionic liquids and polymeric ionic liquids were investigated as solvent and support for immobilization of molybdenum and palladium catalysts. Three newly synthesized room temperature ionic liquids containing molybdate anion, [DMIm][MoO2(NCS)4], [RPy][MoO2(NCS)4] (R = butyl or decyl), and previously reported [BMIm][MoO2(NCS)4] were used as catalysts for the reduction of sulfoxides. For facilitating the recyclability of the catalysts, the ionic liquid solvents, [RMIm][PF6] and [RPy][PF6] (RMIm=1-n-alkyl-3-methylimidazolium, RPy= 1-n-alkylpyridinium), were applied to immobilize molybdenum catalysts. These catalysts showed high catalytic activity for sulfoxide reduction in this... 

In this project synthesis and characterization of a novel dioxomolybdenum(VI), with tetradentates Schiff base ligand which was soluble in water. The first step of complex synthesis was chloromethylation of salicylaldehyde and the second step was the reaction with the pyridine. After that salen ligand will be synthesized by reaction with ethylene diamine. In the presence of Mo(acac)₂(VI) the final product will be synthesized. The complex was characterized by spectroscopic methods such as UV, NMR, FT-IR and CHN. The synthetized complex was studied for olefin (aliphatic and aromatic) epoxidation as well as sulfide oxidation. It was more active in aliphatic olefins epoxidation than sulfide... 

Phase shifters are commonly used in the implementation of phased-array antenna systems.The function of these systems is highly dependent on the performance of phase shifters. In addition, phase shifter circuits are used in some applications such as antenna test and regulation, power amplifier linearization, and QAM modulator implementation, to name but a handful. In this project, design of phase shifter blocks, as well as limitations of fabrication on silicon substrate, is studied and these blocks are designed for maximum bandwidth and minimum sensitivity based on fabrication characteristics and environmental conditions. Design of a 6-bit phase shifter based on vector-sum method is the... 

In this thesis, functionalized Fe3O4 nanoparticles have been utilized as a support for immobilization of homogeneous catalysts. The catalytic activity of the supported heterogeneous nanocatalysts was investigated in hydrocarbon and sulfide oxidation reactions. In the first part of this research, imidazole functionalized Fe3O4 nanoparticles (Fe3O4@SiO2-Im) were used as a support to anchor manganese porphyrin complex, [MnT(4-OMeP)P]OAc; via axial ligation. Catalytic application of the immobilized manganese porphyrin was studied in oxidation of alkenes and sulfides. To find suitable reaction conditions, the effect of different parameters such as solvent and temperature on immobilization process... 

A probabilistic approach to modeling the seismic damage incurred by structural and nonstructural components is developed in this study. For this purpose, Bayesian linear regression is employed to characterize the epistemic uncertainty in the model. In this approach, regressors are constructed based on the mechanics of damage. In turn, the probability distributions of the model parameters and the model error are quantified by Bayesian regression using real-life data from laboratory experiments and/or post-earthquake inspections of damaged components. The study presents the stepwise procedure of collecting the observations, quantifying the repair costs, developing model forms, performing model... 

In this study, a series of polyoxometalates nanoclusters is synthesized and their catalytic properties have been investigated in oxidation and coupling reactions. In the first and second sections, {Mo36} nanoclusters are primarily prepared. Then, the mesoporous silica, as a solid surface with a regular chanals and cavities through electrostatic interactions between polyoxo anions and amine functional groups with positive charge, is used to stabilize the nanocluster as well as the final structure of SBA-15-NH3 +•{Mo36}- formed. As a green and environmentally friendly substrate, natural zeolite is used to stabilize the nanoclusters and the {Mo36}@zeolite obtained. Both heterogeneous catalysts...