Sharif Digital Repository

Herein a simple tow step method is developed to design hierarchical binder free structure of binary nickel cobalt carbonate hydroxide decorated hydrothermal carbon sphere. First carbon sphere were synthesized on nickel foam via hydrothermal process using glucose solution followed by carbonization process. Ni Co carbonate hydroxide core shell array were directly grown on binder free carbon spheres using hydrothermal method. The synthesized electrode afforded high specific capacitance (497/83 mAhg-1 at a current density of 1/4 A g-1) and good cyclic stability (85% after 1500 charge / discharge cycles). EIS measurement showed negligible internal resistance (0.638 Ω) which is attributed to the... 

Nuclear power is a prominent alternative of fossil fuels that can effectively solve global warming, acid rains and other consequences of air pollutions, caused by combustion. Despite such obvious advantage, this highly compact form of energy suffers from a big problem corresponding to its nuclear waste. Graphene oxide (GO), a lamellar material with wide range of surface functional groups such as epoxy (C-O-C), hydroxyl, and carboxyl offers large surface area as well as high sorption capacity for the metallic cations. This thesis study presents a supercritical, and co-precipitation synthesis of magnetite- graphene oxide (M-GO) in which Fe3O4 nanoparticles are simultaneously formed, surface... 

The transient liquid phase bonding is a combination of penetration bonding and hard soldering processes. This method is based on the diffusion in the solid state of the melting point reducing elements from the joint zone into the base metal and isothermal solidification that the kinetics of this reaction are controlled by diffusion in the solid state. In this study, we investigate the bonding of 304 stainless steel with cobalt base interlayer by transient liquid phase method and studies of microstructural and corrosion resistance of the joint. Three different temperatures are considered for the bonding and after each bonding, the microstructure is examined with a optical and scanning... 

Stainless steels have many applications in different industries like chemistry, medicine and food production. So for using these alloys it is necessary to join them with appropriate method. In this research, microstructure-mechanical properties relationship of 304LC austenitic stainless steel transient liquid phase bonded using a Co-based interlayer was investigated. For this purpose, bonding was conducted at 1180 ℃ for different holding times. Microstructure of the joints was evaluated by optical microscopy (OM) and Scanning Electron Microscopy (SEM). The results showed that isothermal solidification (IS) was completed within 1800s and no intermetallic compound was formed in the joint area... 

Increased photo catalytic activity of NiO and 〖Co〗_3 O_4 were obtained by Ni〖Co〗_2 O_4 synthesizing and supporting functionalized multiwall carbon nano-tubes via calcinations followed by hydrothermal precipitation. NiO, 〖Co〗_3 O_4 and Ni〖Co〗_2 O_4 were prepared in the same procedure exactly for the subsequent photo catalytic activity to be compared to Ni〖Co〗_2 O_4/MWCNT later on. The photo catalytic degradation of Reactive Red 120 dye as a deazo organic pollutant model was used for experimental photo catalytic performance analysis. The CCD method was applied for experimental designing, modeling, and optimizing the operational parameters of the photo catalytic degradation of RR120 using... 

Synthesis gas to light olefin reactions especially propylene production is one of the important path for clean fuel production in gas conversion processes. The object of this study is to define true kinetic model of process first step (e.g. Synthesis gas to light Olefins). For that, kinetic model for Co/Mn/TiO2 catalyst, which has the best conversion and selectivity for propylene, has been developed. Kinetic reaction parameters were measured by kinetic modeling in (220-300)0C temperature , (1-5)bar pressure , H2/CO=(1:3) and (450-600)hr-1 space velocity .After studying with significant models ,the best fitting can obtained with "KPCO P 1/2H2/(1+aPco+bPH2 1/2)2"equation. Later to... 

In the first part, Co-Zn hydroxides were deposited onto CuO nanorods, and their electrochemical behavior and capacitive performance were investigated. To this end, Cu(OH)2 nanorods were grown on copper foam through a chemical process. Then, Cu(OH)2 were converted to CuO nanorods via a calcination process. In the next step, Co-Zn-OH sheets were electrodeposited on CuO nanorods. FE-SEM images of the prepared electrodes demonstrate the formation of Co-Zn-OH nanosheets onto CuO nanorods. Crucial electrochemical evaluations such as cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), rate capability, and electrochemical impedance spectroscopy (EIS) were carried out. According to the... 

Energy and the environment issues are among the most important concerns of the present age. Global demand for energy is growing rapidly and energy demand is projected to double in the coming years. However, today most of the energy consumption comes from fossil fuels, which have limited and unstable reserves and are among the sources of environmental pollution. Hence, the production and conversion of clean energy from renewable sources is considered as an intelligent solution to significantly reduce dependence on fossil fuels and protect the environment. Fuel cells, metal-air batteries, and water electrolysis are among the simplest, most efficient, and most reliable technologies among... 

The magnetic MOF-based catalytic system has been reported here to be an efficient catalyst for running CDC reactions and synthesis of Triazole rings under optimal conditions. The robust MOF catalyst was built based on magnetic nanoparticles and HKUST-1 which further modified with thioacetamide and carbonization. The catalyst structure was confirmed by various techniques. Furthermore, the products’ yields were obtained in good to excellent for all reactions under mild conditions which result from superior activity of the synthesized heterogeneous catalyst containing Cupper. Also, the magnetic property of the MOF-based catalyst makes it easy to separate from reaction mediums and reuse in the... 

Co(salen)-type complexes: Co(salen), Co(salophen), Co(3,5-Brsalen), Co(Clsalen), Co(3-OMe,5-Brsalen), Co(saltmen), Co(Brsalen), Co(OMesalen) were shown to be efficient catalysts for oxidizing cumene to cumyl alcohol, methylstyrene and acetophenone. The mixture was characterized by 1H NMR and GC-Mass spectroscopy. Product s efficiency and turnover number of catalysists were determined. Proposal of the mechanism provides a rationale for the influence of ligand substitutions on the reaction. A series of experiments are reported to provide strong support for a mechanistic scheme that involves reaction of coordinated dioxygen. On the basis of these observations, the coordination of O2 to this... 

Nuclear waste management in Iran is the responsibility of the Nuclear Waste Company. The waste company is obliged to bury waste with a certain level of radioactivity, resulting from various processes of the nuclear fuel cycle or other processes such as research projects and medical centers, after the necessary measures, finally at the Anarak landfill site. To evaluate the safety of the site, it is necessary to study the parameters of radioactive nucleation in the soil. Humic substances from natural substances in the soil affect the transport of radioactive nuclei. In this project, to study the effects of the presence of humic acid, the soil of Anarak residue in three weight percent... 

Considering the operation of the current nuclear reactors and the country's policy to achieve 10,000 megawatts of nuclear power in the horizon of 1420, as well as the construction of research reactors, we will face a huge amount of radioactive waste in the coming years. Meanwhile, spent ion exchange resins constitute a large amount of low and intermediate level (LILW) solid radioactive waste produced from the nuclear industry. Therefore, appropriate precautionary measures should be taken for the immobilization and disposal of these radioactive wastes in order to ensure the sustainable development of the nuclear industry and the protection of the environment and human health. In this study,... 

Considering the widespread applications of amides, synthesis of these compounds is of great importance. The one pot oxidative addition of amines to aldehydes is one of the most simple and appealing approaches to synthesis amides. With the aim of developing a mild and convenient approach towards preparation of amides, numerous methods have been reported for this important process over the past few decades. These improvements have been mostly related to the optimization of reaction conditions and the use of more challenging substrates including diverse derivatives of aldehydes, and also design a novel and effective catalytic systems. Due to the various advantages of supported heterogeneous... 

Emission of aromatic and aliphatic compounds to atmosphere is a major environmental concern for many urban societies. Catalytic oxidation of volatile organic compounds (VOCs) is an efficient and low operating cost technology for reduction of air pollution.
First, dispersed copper oxide nano-catalysts supported on almond shell-based activated carbon were prepared for catalytic oxidation of toluene in air. The Response Surface Methodology (RSM) was used to express the catalyst removal efficiency in terms of catalyst metal loading and calcination temperature. Calcination temperature had a significant effect on the catalyst activity only at high metal loadings (upper 8% wt.). Two different... 

In this study, the effect of temperature on the microstructure and electrochemical properties of the NMC batteries has been studied. An extensive set of accelerated aging tests has been carried out employing a Li-ion high energy 18650 system (2.2 Ah, negative electrode: carbon, positive electrode: Li(Ni0.5Mn0.3Co0.2) O2. Different influence factors on cycle aging, such as temperature and discharge rate have been investigated. The aged 18650 cells have been inspected via scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), impedance spectroscopy, and X-ray diffraction (XRD) after disassembly to find more information about the chemical reasons of the degradation and... 

In this study, granular activated carbon has been modified by potassium nickel hexacyanoferrate ( KNCF), sodium dodecyl sulfate(SDS) and ammonium per sulfate(APS) as new adsorbents for cesium, cobalt and chromium(VI), respectively. The prepared adsorbents were characterized using powder X-ray diffraction(XRD), nitrogen adsorption-desorption isotherm data, infrared spectroscopy, scanning electron microscopy coupled with energy dispersive spectroscopy(SEM-EDS) and their adsorption performance were investigated. The effect of various parameters like the initial pH value of the solution, contact time, temperature, strength ionic of the solution, interference ions and the initial concentration of... 

In this research a copper- Tungsten carbided nanocomposite coating prepared by electrodeposition from a sulfate bath in order to increase the hardness and erosion resistance of cooper without loosing cooper's specific physical properties as like as electrical and thermal conductivity. Various parameters were evaluated for finding significant factors in electrodeposition of Cu-Co/WC composite. Current density and concentration of WC and SDS were selected as affective factors. The morphology and structure were characterized by XRD and SEM. The mechanical properties of the coatings, such as hardness, wear resistance and surface roughness were studied with Vickers hardness indentation; pin on... 

The aim of this study at the outset is synthesis of ligands with the ability to bridge formation between two groups i.e. C60 and Cobalt Schiff base complex (CoSALEN). Hence, four Schiff base ligands with pyridine electron donor moiety in one side, and such electron donor moiety pyridine, phenol and aniline in another side were synthesized and characterized by elemental analysis, 13C¬NMR, 1HNMR and IR Spectroscopy. In next step the interaction of these Schiff base ligands with CoSALEN complex and Fullerene C60, in the mixture of two solvents, i.e. toluene/dimethylsulfoxide and benzene/methanol was explored separately by UV-Visible Spectroscopy and their kinetic studies were also undertaken... 

Energy and the environment issues are among the most important concerns of the present age. Global demand for energy is growing rapidly and energy demand is projected to double within the next 15 years. However, today most of the energy consumption comes from fossil fuels, which have limited and unstable reserves and are among the sources of environmental pollution. Hence, the production and conversion of clean energy from renewable sources is considered as an intelligent solution to significantly reduce dependence on fossil fuels and protect the environment. Fuel cells, metal-air batteries, and water electrolysis are among the simplest, most efficient, and most reliable technologies among... 

Fischer-Tropsch synthesis is a major part of gas-to-liquid (GTL) technology, which converts natural gas into liquid fuels with very low sulfur and aromatic content. Nowadays, this exothermic reaction is performed in slurry reactors; therefore it is essential to separate solid catalyst particles, suspended in the liquid products. In this study, without performing real experiment and chemical reaction, separation of Alumina supported Cobalt Catalyst from wax is carried out by internal filtration. For the first time in this research, the effect of different parameters like pressure difference, wax viscosity and filter pore size on the quantity and quality of filter performance is investigated....