Sharif Digital Repository

Thin films of titanium dioxide with high surface area are prepared by sol-gel dip-coating technique. In this regards, Titania nano sols with high photocatalytic activity were prepared by dissolving titanium alkoxide in alcohol and water under acidic conditions. Photocatalytic activities of titanium dioxide thin films were measured in the presence of methylene blue. Microstructure and photocatalytic activity of the films, nanopowders and titanium dioxide sols were investigated using X-ray diffraction, scanning electron microscopy, specific surface area, zeta sizer and ultraviolet-visible spectrometry techniques. Particle size analysis of sols showed that the mean particle sizes were 15 to 128... 

Petrography and image analysis have been widely used to identify and quantify porous characteristics in carbonate reservoirs. This paper uses the thin section images of 200 carbonate rock samples to predict the absolute permeability using intelligent and empirical methods. For each thin section, several pore network parameters are extracted from thin section images of rocks including the average pore size, average throat size, average throat length and average 2-D coordination number of pore network. A neural-based model successfully predicts the permeability of samples using pore network parameters as the inputs. Second neural network is applied for predicting absolute permeability... 

A coupled statistical and conditional generative adversarial neural network is used for 3D reconstruction of both homogeneous and heterogeneous porous media from a single two-dimensional image. A statistical approach feeds the deep network with conditional data, and then the reconstruction is trained on a deep generative network. The conditional nature of the generative model helps in network stability and convergence which has been optimized through a gradient-descent-based optimization method. Moreover, this coupled approach allows the reconstruction of heterogeneous samples, a critical and serious challenge in conventional reconstruction methods. The main contribution of this work is to... 

A non-collimated gamma spectroscopy with fewer sampling (counting) and shorter sampling periods is developed and used to estimate the concentration profile of the radiotracers within the column. In this method, the radiotracer activity in the whole column is measured in a few different positions of the detector and then, by using an appropriate advection-dispersion model and the genetic algorithm, the concentration profile within the column is constructed. The concentration profile obtained by the new method fits very well to the experimentally obtained thin-section scanning results with RMSE less than 0.046. The uniqueness of the concentration profile obtained by the method was confirmed by... 

In the last decade, the power conversion efficiency (PCE) of solution-processed perovskite solar cells (PSCs) in the lab-scale has reached an incredible level of 25.5%. Generally, PSCs are composed of a stack consisting of a perovskite thin-film sandwiched between an electron transporting layer (ETL) and a hole transporting layer (HTL). Although the quality of the ETL and HTL interfaces with the perovskite thin-film is important, the quality of the perovskite thin-film is also critical to achieving high-performance PSCs. Low-temperature deposition of organic-inorganic perovskite thin-films by simple solution processes is one of the significant advantages of PSCs compared to other... 

The construction of a facies model could be employed as a conditional data for any property simulation that results in a more reliable reservoir characterization in further steps. In this study, an Iranian gas reservoir with six wells was studied to determine the 3D reservoir facies model. Fifteen reservoir facies were first detected along one of the wells with detailed core and thin section descriptions. Due to the significant difference between the core and log data resolution, facies were clustered into four major groups regarding the digenetic processes and petrophysical lithofacies properties (permeability and porosity). The lithofacies specification effect on petrophysical properties... 

This study concerns with the microscopic and macroscopic fluid distribution and flow behavior during water alternating solvent (WAS) injection process to heavy oil using micromodel generated from thin section of a real rock which has rarely attended in the available literature. In this study, a one-quarter five-spot glass micromodel was deployed to examine the effect of flow media topology on microscopic displacements as well as macroscopic efficiency of WAS process. The micromodel was initially saturated with the heavy oil, and then the hydrocarbon solvent and water were injected alternately into it. The observations confirmed that WAS injection scheme is an effective method for the... 

Fluid flow behavior in a porous medium is a function of the geometry and topology of its pore space. The construction of a three dimensional pore space model of a porous medium is therefore an important first step in characterizing the medium and predicting its flow properties. A stochastic technique for reconstruction of the 3D pore structure of unstructured random porous media from a 2D thin section training image is presented. The proposed technique relies on successive 2D multiple point statistics simulations coupled to a multi-scale conditioning data extraction procedure. The Single Normal Equation Simulation Algorithm (SNESIM), originally developed as a tool for reproduction of...