Sharif Digital Repository

This study is undertaken to evaluate the potential of a commercial molecular sieve to remove diverse sulfur compounds from condensate with high aromatic on an industrial scale. For the first part of this study, the adsorbent is characterized in detail using inductively coupled plasma optical emission spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, and Brunauer-Emmett-Teller analysis. For the second part, dynamic breakthrough experiments on an industrial scale are performed to assess the dynamic adsorption performance of a commercial molecular sieve. Dynamic experiments show that the adsorbent effectively removes the sulfur compound from condensate that has... 

Adaptive Reuse is a relatively new approach that aims to restore the relationship between humans and nature by providing a set of concepts and methods that lead to a sustainable interaction between the two. While the ecological approach is one of the most well-known sustainability sciences, it only considers the physical aspects of the relationship between humans and nature and does not account for its semantic dimensions. This research seeks to answer the question of which approach is most effective in establishing a stable relationship between humans and the environment. To achieve this, this article examines the theoretical foundations of Adaptive Reuse and the pathology of the... 

This paper presents a broad-band bandpass filter (BPF) designed as a channel-select filter for wireless applications. It is implemented as a low-pass filter (LPF) in series with a high-pass filter (HPF) for lower power consumption compared to true BPF. Semiscaling of the filter nodes is superior in the wireless receiver over traditional full scaling. The HPF is built with low-pass feedback of an amplifier. The bandwidth is selectable from 625 kHz, 2.5 MHz, or 10 MHz. The filter stopband loss is more than 50 dB extending beyond 100 MHz, and passband ripple less than 2.5 dB. Fabricated in a 0.6-μm CMOS process, it provides a minimum input noise of 16 nV/√Hz noise with 22.5-dBm out-of-band... 

We show that a metal-organic framework (MOF) sustained by a nanosized Ag12 cuboctahedral node can be applied to selectively extract traces of lead(II) ion from environmental water samples. The MOF was characterized by thermogravimetric and differential thermal analysis, scanning electron microscopy, FTIR, and X-ray diffraction. The effects of pH value, flow rates, of type, concentration and volume of the eluent, of break-through volume and potentially interfering ions on the separation and determination of lead were evaluated. Following desorption with EDTA, Pb(II) was quantified by FAAS. The use of the MOF results in excellent analytical figures of merit including an analytical range from 2... 

The influx of solid or liquid particles of drilling mud into the pores of rock or mud loss phenomenon and clay swelling can sometimes lead to severe productive formation damage and cause to wettability alterations of reservoir rock from hydrophilic to oleophilic. Therefore, designing an appropriate fluid that is compatible with formation fluids and could reduce reservoir damage and increase the productivity of wells is very important. The two main mechanisms of surfactants are reduction of the surface tension and wettability alteration of rock reservoir that are effective in taking the oil. Regarding the importance of the wettability in reservoir productivity, this article is aimed to study... 

The influx of solid or liquid particles of drilling mud into the pores of rock or mud loss phenomenon and clay swelling can sometimes lead to severe productive formation damage and cause to wettability alterations of reservoir rock from hydrophilic to oleophilic. Therefore, designing an appropriate fluid that is compatible with formation fluids and could reduce reservoir damage and increase the productivity of wells is very important. The two main mechanisms of surfactants are reduction of the surface tension and wettability alteration of rock reservoir that are effective in taking the oil. Regarding the importance of the wettability in reservoir productivity, this article is aimed to study... 

Abstract In this work, two [60] fullerene derivatives were employed as flow improvers for waxy crude oil to reduce problems caused by the crystallization of paraffin during the production and/or transportation of the crude oil. These amine-based derivatives of [60] fullerene have been applied as wax inhibitor for improvement of rheological performance as well as pour point depressant in a waxy crude oil. Moreover, the influence of these [60] fullerene derivatives on the viscosity and pour point was also investigated in an Iranian waxy crude oil sample. The [60] fullerene derivatives were simply prepared by stirring a solution of [60] fullerene and two lipophilic amines. The results similarly... 

Removal of aromatic compounds from fuel is an essential requirement in new environmental policies. In the present study, poly(vinyl alcohol)/graphene oxide (GO) mixed matrix membranes were prepared and applied to the separation of toluene from iso-octane by pervaporation, considering the similarity and interaction between graphene and aromatics. The effects of crosslinking and GO content on separation efficiency have been investigated in detail. Owing to the high affinity of GO with toluene through s and π bonds, the selectivity of the membranes was increased by incorporating a low amount of GO. The results also indicated that noncrosslinked membranes have higher selectivity and permeation... 

Discrimination of chiral targets is generally achieved with chiral nanomaterials. However, the limited number of intrinsic chiral nanostructures as well as their complex synthesis procedure has led to the production of chirality-induced nanomaterials as alternatives. Chirality can be induced in nanomaterials by either chirality transfer or the formation of chiral assemblies. Using the latter approach, in this work, we have provided chiral supramolecular assemblies of CdTe quantum dots (QDs) from achiral starting materials. CTAB-QD assemblies showed chiroptical activities, and their orange emission in combination with the blue emission of carbon dots was utilized as a ratiometric chiral... 

In this work, a new model based on multilayer kinetic adsorption mechanism has been proposed to account asphaltene adsorption in porous media under dynamic condition and the model was verified using experimental data obtained in this work and also with those reported in the literature. In the proposed model two steps are considered for asphaltene adsorption. The first step is taken as adsorption of asphaltenes on the surface of the porous media and the second step is taken as adsorption of asphaltenes on the asphaltenes already adsorbed on the porous media. The Crank-Nicholson method, central difference in space and trapezoidal rule in time, giving second order convergence in time was... 

In this work, asphaltene adsorption in a sandstone core sample under dynamic conditions and during miscible CO2 injection was studied using live oil sample which is close to real conditions in petroleum reservoirs. In order to investigate of damage in sandstone core sample by the deposited material such as asphaltene, the morphology analysis of sandstone core sample using scanning electron microscopic method was studied. Also analyses of the adsorbed material in sandstone core sample by Soxhlet extraction using an azeotrope mixture and with SARA method were performed. The experimental results show that by increasing the flow rate of injected CO2, the amount of asphaltene in retained material... 

The process of asphaltene precipitation has a substantial effect on oil flow during primary oil production and enhanced oil recovery processes in the petroleum industry. In this work, a modified scaling model based on the PVT properties of bottom hole live oil including resin to asphaltene ratio, onset pressure, bubble point pressure, reservoir temperature, asphaltene content of bottom hole live oil and gas to oil ratio has been proposed to account for asphaltene precipitation under pressure depletion/gas injection conditions and the proposed model was verified using experimental data obtained in this work and also with those reported in the literature. In the proposed scaling model the... 

In this paper, oil recovery and permeability reduction of a tight sandstone core sample in miscible CO2 flooding processes due to asphaltene deposition were studied using an Iranian bottom hole live oil sample in order to distinguish between the mechanical plugging and adsorption mechanisms of asphaltene involved in the interfacial interaction of the asphaltene/mineral rock system. A novel experimental method was designed and proposed to measure the amount of deposited asphaltene due to different mechanisms using the cyclohexane or toluene reverse flooding and spectrophotometer. In this work, the bottom hole live oil sample was injected first to a long core and then CO 2 injection was... 

In this work, a new model based on the multilayer adsorption kinetic mechanism and four material balance equations for oil, asphaltene, gas, and water phase has been developed to account for asphaltene deposition in porous media under dynamic conditions and the model was verified using experimental data obtained in this work and also with those reported in the literature. The results showed that the developed model based on multilayer adsorption kinetic mechanism can correlate more accurately the oil flooding experimental data in comparison to the previous models based on the mechanical plugging mechanism, in particular in carbonate core samples. Also, a series of experiments was carried to... 

Asphaltene deposition causes serious problems in the oil industry. Variation of oil composition and reservoir pressure is reported to be the most important factors that influence asphaltene deposition from reservoir oil. In this study, a mathematical model was developed to simulate asphaltene deposition during primary depletion and CO2 injection. The main purpose of this study is to investigate and to compare asphaltene deposition mechanisms due to primary depletion and CO2 injection. The solid model as thermodynamic model was applied to investigate asphaltene precipitation. A numerical model was established to the governing equations both in space and time and model parameters were... 

Asphaltene precipitation may occur during pressure depletion or gas injection processes in a reservoir. This phenomenon is an important problem during oil production, because it can result in formation damage and the plugging of wellbore and surface facilities. In this work, the precipitation of asphaltenes in an Iranian crude oil, under different pressures, is measured, using an experimental set up based on high-pressure isothermal expansion and also atmospheric titration. For the particular oil investigated, compositional data, precipitation phase diagrams, and bubble point and onset pressures are reported. Also, in this work, the Perturbed Chain form of the Statistical Associating Fluid... 

In this work, experimental studies were conducted to determine the effect of asphaltene deposition on the permeability reduction and porosity reduction of carbonate, sandstone and dolomite rock samples using an Iranian bottom hole live oil sample which is close to reservoir conditions, whereas in the majority of previous work, a mixture of recombined oil (a mixture of dead oil and associated gas) was injected into a core sample which is far from reservoir conditions. The effect of the oil injection rate on asphaltene deposition and permeability reduction was studied. The experimental results showed that an increase in the oil injection flow rate can result in an increase in asphaltene... 

Discrimination of chiral targets is generally achieved with chiral nanomaterials. However, the limited number of intrinsic chiral nanostructures as well as their complex synthesis procedure has led to the production of chirality-induced nanomaterials as alternatives. Chirality can be induced in nanomaterials by either chirality transfer or the formation of chiral assemblies. Using the latter approach, in this work, we have provided chiral supramolecular assemblies of CdTe quantum dots (QDs) from achiral starting materials. CTAB-QD assemblies showed chiroptical activities, and their orange emission in combination with the blue emission of carbon dots was utilized as a ratiometric chiral... 

This study presents the application of the Proposed Modified Reduced-Order Aerodynamics Modelling approach for aeroelastic analysis based on the boundary element method (BEM) as a novel approach. The used BEM has the capability to capture the thickness effect and geometric complexity of a general three-dimensional model. In this approach the reduced-order aerodynamic model is defined through the eigenvalue problem of unsteady flow based on the unknown wake singularities. Based on the used aerodynamic model an explicit algebraic form of the aeroelastic equations is derived that reduces computational efforts and complexity. This special feature enables us to determine the aeroelastic... 

This paper presents a coupled flap-lag-torsion aeroelastic stability analysis and response of a hingeless helicopter blade in the hovering flight condition. The boundary element method based on the wake eigenvalues is used for the prediction of unsteady airloads of the rotor blade. The aeroelastic equations of motion of the rotor blade are derived by Galerkin's method. To obtain the aeroelastic stability and response, the governing nonlinear equations of motion are linearized about the nonlinear steady equilibrium positions using small perturbation theory. The equilibrium deflections are calculated through the iterative Newton-Raphson method. Numerical results comprising steady equilibrium...