Sharif Digital Repository

In this project a new molybdenum (VI) complex with tetradentate Schiff base ligand which was soluble in water was synthesized and characterized. In the first step of ligand synthesis, the reaction was performed between salicylaldehyde and aniline, and then used concentrated sulfuric acid for sulfonation. In the next step 5- sulfosalicylaldehyde sodium salt was formed by removing of aniline with heating and using sodium carbonate. In the presence of ethylendiamine and bis (acetylacetonato) dioxomolybdenum(VI) the final product, cis-dioxo sodium (N,N-bis (5-sulfonatosalicyldene)1,2-diaminoethane) molybdenum (VI) complex was synthesized. The complex was characterized by (CHN) elemental... 

New dioxomolybdenum(VI) complex has been synthesized by reacting N-hydroxyphenyl-[5-(triphenylphosphonium)methyl]salicylideneamine chloride (PPh3-H2sap) as a water soluble ligand and [MoO2(acac)2] in ethanolic solution. The water soluble ligand (PPh3-H2sap) was prepared by reaction of 2-aminophenol with (3-formyl-4-hydroxybenzyl)triphenylphosphonium chloride as a water solublesalicylaldehyde derivative. The resulting complex with the formula [MoO2(PPh3-H2sap)(EtOH)] which contains an ethanol molecule in sixth site of coordination, was characterized by elemental analyses, 1H NMR,31P NMR, IR and UV-Vis spectroscopic studies. This complex was tested as a catalyst for the homogeneous... 

In most radio receivers like superheterodyne receivers, a weak desired incoming signal is accompanied with many interferer signals that are much more powerful than the desired signal itself. These interferers, also called blockers, can cause a great disturbance in the functionality of the receiver. Due to gain compression and an increase in the noise figure (NF) of the receiver, the blockers should be filtered before the arrival at the output of the LNA. Because of the low quality factors of the available on chip inductors and in order to eliminate the out of band interferer signals and image frequency (in superheterodyne receivers), usually an external surface acoustic wave (SAW) filter is... 

In this study a new Ni(II)-¬oxazoline complex was synthesized by reaction of Ni(CH3COO)2.4H2O and 2-(2׳-hydroxyphenyl)-2-oxazoline ligand in MeOH solvent. The resulting complex bis[2-(2׳-hydroxyphenyl)-2-oxazolinato]Ni(II), was characterized by different spectroscopic methods. X-ray diffraction showed that this complex is four coordinated with a square planner geometry. The complex was applied as an efficient homogeneous catalyst in C-C coupling Heck reaction of arylhalides with olefins such as methylacrylate. Investigation of the catalytic activity of the complex in Heck reaction between arylhalides and olefins showed high yield and selectivity. For example reaction between iodobenzene and... 

A web-based system is designed and implemented at cira.civil.sharif.edu as a risk communication tool to incentivize the society to take seismic risk mitigation measures. Risk denotes the expected monetary and social losses herein. The objective of this system is to raise the awareness of two groups of audience, i.e., the general public and policymakers,about the significant seismic risk in Iran. To address the general public, the system employs the notion of risk perception to put the results of sophisticated earthquake engineering risk analyses into perspective. The system also treats the epistemic uncertainty in the user input due to general public’s lack of technical knowledge through the... 

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... 

A new dioxomolybdenum(VI) complex, (Cis-[MoO2(L)])n, has been synthesized by reacting 4-bromo-2-((2-hydroxy-5-methylphenylimino)methyl)phenol as a ligand and [MoO2(acac)2] in methanolic solution. For characterization and structure determination of the synthesized complex, different techniques were performed such as elemental analyses, 1H NMR, IR, UV-Vis and X-ray crystallography. The complex was tested as a catalyst for the homogeneous epoxidation of olefins, using tert-butyl hydperoxide (TBHP) as an oxidant. The catalytic system showed high yield, selectivity and turnover number in olefin epoxidation reactions under atmospheric conditions. For example, when the molar ratio of catalyst,... 

Two new copper(II) complexes, [CuL2] and [Cu(phox)2], were synthesized by reaction of 1-((4-bromophenylimino)methyl)naphthalen-2-ol, HL, and 2-(2′-hydroxyphenyl)-2-oxazoline, Hphox, as ligands and copper(II) acetate mono-hydrate with the ratio 2:1 (ligand:metal), respectively. For characterization and structure determination of synthesized complexes, different techniques were performed such as FT-IR, elemental analyses (CHN), and X-ray crystallography. The geometry around Cu atom is almost square planar in both complexes. The catalytic activity of the complexes was evaluated in azide–alkyne cycloaddition reaction in water without need of any additional agent. The reaction conditions for the... 

Composite production is an important method for increasing abrasion resistance in materials. Friction stir processing (FSP) is a solid composite production method which has eliminated the problems of liquid composite production. This research used FSP to study the possibility of in situ production of 1050 aluminum composite with a mixture of copper and iron powder with micrometer sizes of 25-14 and 10 μm, respectively, as reinforcing particles. The following weight percentages of reinforcing powder was added to the sample: 75% iron-25% copper, 50% iron-50% copper and 25% iron-75% copper. In addition, 3 and 5 process passes were considered as another variable in this study. Afterward, the... 

Martensitic stainless steels with high strength, good corrosion resistance and formability in the annealed condition are good choices for automotive applications, but they suffer from low weldability due to high hardenability and formation of brittle martensite without tempered structure in the weld metal and heat affected zone (HAZ). In other word, martensitic stainless steels have the worst weldability among all kinds of stainless steels. On the other hand, resistance spot welding is the main method for joining sheets in the automotive industry. Therefore, in the present work, microstructure and mechanical properties of the resistance spot welds of AISI 420 martensitic stainless steel in... 

This study proposes a probabilistic framework to quantitatively evaluate the resilience of a community comprising a building stock, commercial facilities, and interdependent infrastructure systems. To this end, the proposed framework employs Monte Carlo sampling in which each sample comprises multiple stages. The sample starts with the occurrence of a hazard event. It then follows by evaluating the consequences incurred by the community in the face of the hazard event. It is concluded by simulating the operations aimed at complete recovery of the community comprising inspection, rescue and relief, restoration, and recovery. For this purpose, chains of interacting probabilistic models are... 

Upset Resistance Welding (URW) is a solid-state joining process which can be used to join a variety of parts and profiles including railways, wheel rims and pipes used in oil and petrochemical industries. This process has three primary parameters, welding current, current passage time and mechanical pressure. Martensitic Stainless Steels (MSSs) due to high strength and wear resistance, good atmospheric corrosion resistance and relatively low price and Duplex Stainless Steels (DSSs) because of higher strength and better corrosion resistance in chlorine environments, are widely used in different industries. Dissimilar MSS/DSS joints are of great importance for piping, specially in oil and... 

The goal of this study is to synthesise and study the catalytic properties of a Mn-Porphyrin complex fixed on a magnetic nanoparticle bed. This nanocatalyst was used in oxidation of sulfides and epoxylation of olefin. In the multistage synthesis of this catalyst, iron oxide magnetic nanoparticles were first prepared, then, by silanizing these nanoparticles, and then using the 3-chloropropyltrimethoxy methanol reactor, Immobilzation the material on the substrate and immediately react in reaction Substitution of the nucleus of friendship and using a sodium azide reaction, bromide is replaced by azide. Subsequently, by synthesising 4-hydroxy porphyrin and replacing one of its positions with... 

In this dissertation a special category of RF filters known as multi-path filters are introduced, chracterized and implemented. The center frequency of the multi-path filters can be tuned by changing the frequency of the clocks applied to the filter, which makes them attractive for use in multi-standard receivers. In this thesis, different types of multi-path filters are studied and by proposing different circuits, their various applications are covered. First, the concept of multi-path filters and their chracteristics are studied. Then a novel technique to analyze these filters based on Fourier analysis is proposed and then, based on this analysis, a new circuit architecture with reduced... 

The main aim of present thesis is to synthesis and characterize of ferrite nanocomposites as a new generation phtocalyst and their application in degradation of various types of environmental pollutants in different irradiation time and dark conditions. Ferrites have been used anchored to carbon allotropes such as graphene oxide and carbon nanotubes, in order to improve their photocalytic activity as well as phase structure, textural and optical properties. Firstly, a new SnS2-BiFeO3/rGO nanocomposite has been prepared to increase the visible-light-responsive photodegradation of organic dyes such as cationic methylene blue (MB) and anionic methyl orange (MO). The obtained results showed... 

In this study, community resilience after a disaster is optimally enhanced for interdependent infrastructures through prioritization of recovery operations considering limited resources. Optimal enhancement of community resilience can be performed at two levels: Pre-disaster and Post-disaster. In the pre-disaster level, resilience enhancement is achieved through optimization of long-term decision making that includes optimized allocation of resources to retrofit of buildings. However, in the post-disaster response and recovery period, allocating resources to retrofit or backup systems is infeasible. Therefore, in the post-disaster level considered in this study, resilience enhancement is... 

The primary objective of this thesis is comprehensive treatment of epistemic uncertainties in probabilistic seismic hazard analysis based on structural reliability methods. The classical methods of probabilistic seismic hazard analysis, i.e., PSHA, traditionally consider a limited number of uncertainties. The ones that they do consider comprise the aleatory uncertainty in the magnitude, the distance, and the residuals of ground motion prediction equations and the epistemic uncertainty in the intensity measures predicted by different such equations. However, there are many sources of epistemic uncertainty that, according to past studies, have a significant impact on the upper tail of the... 

In the communication systems, there are two types of blockers: in-band and out-of-band. High frequency pre-filters and band-pass filters can be used to suppress the out-of band blockers. However, using these methods does not affect the in-band interferers. Spatial filtering by means of phased array antennas and using frequency filtering can suppress both types of interferers. In a typical phased array receiver, all of the received signals pass through active blocks (such as LNAs, active phase shifters, driver amplifiers, etc.) that amplify the interferers before canceling them. Therefore, because of the high strength of the interferers, the dynamic range of the front-end blocks preceding... 

Friction stir spot welding (FSSW) as a solid-state process is able to tackle some problems of fusion welding. On the contrary, FSSW has some drawbacks such as the low area of connection and weakness in fatigue behavior. In this study, an innovative method called friction stir spot welding via consumable pin (CP-FSSW) was used, which was able to eliminate the exit-hole. In this process, at the first stage, a hole is created in the center of the overlap area of the sheets; such that the hole is complete in the upper sheet and up to the half thickness of the lower sheet. Then, the rotating tool composed of a consumable pin with diameter length as much as the created hole and same type of the... 

In this study, a polyoxotungestate containing copper was impregnated as catalyst on a magnetic metal-organic framework (Fe3O4/MIL-101(Cr)). Initially, the desired polyoxotungestate was synthesized using sodium tungestate and sodium metasilicate salts and then copper(ІІ) ion was fixed on it. Subsequently, the MIL-101(Cr) metal-organic framework was prepared by solvothermal method; using chromium nitrate salt and 1,4-benzen dicarboxylic acid at 220 ◦C and was magnetized by co-precipitation method. Finally, the corresponding polyoxotungestate was stirred at ambient temperature for 24 h with MIL-101(Cr) and then the brown precipitate was separated using a magnet. Different techniques such as IR,...