Sharif Digital Repository

Carbon dioxide (CO2) has an essential role in most enhanced oil recovery (EOR) methods in the oil industry. Oil swelling and viscosity reduction are the dominant mechanisms in an immiscible CO2-EOR process. Besides numerous CO2 applications in EOR, most oil reservoirs do not have access to natural CO2, and capturing it from flue gas and other sources is costly. Flue gases are available in huge quantities at a significantly lower price and can be considered economically viable agents for EOR operations. In this work, four powerful machine learning algorithms, namely, extra tree (ET), random forest (RF), gradient boosting (GBoost), and light gradient boosted machine (LightGBM) were utilized to... 

With the increased load demand and generation cost of electricity, renewable energy sources (RES) provide cost effective and environment-friendly solution. Integration of solar energy includes the challenges of finding the Maximum Power Point (MPP) to achieve the maximum power from the solar. Combining RESs with distributed generation (DG) comes with the challenges of voltage regulation and frequency mismatch. In this work, a novel approach of Robust Antlion Optimizer (ALO) algorithm is implemented for MPP tracking in solar photovoltaic (PV) system and charge controllers are designed for storage system while the DC to AC converters have been designed to match RESs’ frequency with that of DG.... 

We develop Hyperion a Wearable Augmented Reality (WAR) system based on Google Glass to access text information in the ambient environment. Hyperion is able to retrieve text content from users' current view and deliver the content to them in different ways according to their context.We design four work modalities for different situations that mobile users encounter in their daily activities. In addition, user interaction interfaces are provided to adapt to different application scenarios. Although Google Glass may be constrained by its poor computational capabilities and its limited battery capacity, we utilize code-level offloading to companion mobile devices to improve the runtime... 

Using natural gas combined with diesel fuel in diesel engines provides a considerable contribution to modern industrial societies in order to control air pollution and, also, generalize and facilitate the use of public vehicles. In spite of the attractive features of this idea, including reduction of NO(X) and particulates, there is an important burden imposed upon the system at low to intermediate torques, namely high concentration of CO and unburned total hydrocarbons (THC), mostly composed of methane. In this work, based upon the oxidation of CO and unburned HCs and through experimental results, application of a monolithic oxidizing bifunctional catalytic converter as a novel... 

P300 based Speller systems are a typical application of BCIs that can be used as a communication device for users with spinal cord injury. In this paper, three different RSVP paradigms; single, dual and triple RSVP are compared in terms of character detection accuracy and ITR to find the optimal communication method for these users. Three subjects were tested to compare these methods in offline mode. The results of this comparison shows that character detection accuracy for the single, dual and triple RSVP paradigms are 0.78, 0.63 and 0.64, respectively. The mean of ITR for the single, dual and triple RSVP paradigms was also recorded to be 3.6534, 7.72 and 11.5 bit/min, respectively.... 

Dye-sensitized upconversion nanoparticles (UCNPs) have gained significant interest in biological applications. However, previous attempts to utilize these dye-sensitized UCNPs in the aqueous environment suffer from dramatic decline in the upconversion luminescence (UCL) intensity and problems with nanoparticles aggregation and water quenching. By employing indocyanine green (ICG) as a hydrophobic amplifier and energy harvester for UCNPs, we use a general, facile, and kinetically controlled mixing technology—flash nanoprecipitation (FNP)—to prepare aqueous stable ICG-sensitized UCNPs encapsulated by a biocompatible block copolymer poly (ethylene glycol)-b-poly (lactic-co-glycolic acid... 

Pesticides are widely used to increase agricultural productivity, however, weak adhesion and deposition lead to low efficient utilization. Herein, we prepare a nanopesticide formulation (tebuconazole nanopesticides) which is leaf-adhesive, and water-dispersed via a rapid nanoparticle precipitation method, flash nanoprecipitation, using temperature-responsive copolymers poly-(2-(dimethylamino)ethylmethylacrylate)-b-poly(ε-caprolactone) as the carrier. Compared with commercial suspensions, the encapsulation by the polymer improves the deposition of TEB, and the contact angle on foliage is lowered by 40.0°. Due to the small size and strong van der Waals interactions, the anti-washing efficiency... 

Learning a foreign language encompasses a process of trial and error that can lead to the progression of the learner's interlanguage, meaning that the learners make use of their language knowledge that receives feedback and brings about progress through diagnosis of the problems and being corrected by the teacher. Therefore, there exists a need to analyze the underlying reasons causing the students to remain taciturn with a low willingness to communicate (WTC) during a language class. There has been much work done investigating the role of the learner's stable personal characteristics (traits) along with their situational changes at a specific time (states) that influence the student's... 

Using 3-D scanned data to analyze and extract pore network plays a vital role in investigation of porous media's characteristics. In this paper, a new simple method is developed to detect pores and throats for analyzing the connectivity and permeability of the network. This automated method utilizes some of the common and well-known image processing functions which are widely accessible by researchers and this has led to an easy algorithm implementation. In this method, after polishing and quality control of images, using city-block distance function and watershed segmentation algorithm, pores and throats are detected and 3-D network is produced. This method can also be applied on 2-D images... 

In this paper, we try to recognize and distinguish different groups of arrhythmia using novel features which have been obtained from the heart rate's phase space in recent years. For this purpose, we used Triangular Phase Space Mapping (TPSM) and Parabolic Phase Space Mapping (PPSM). For recognition, we used three groups of 15 subjects using the Physionet database (Arrhythmia, Congestive Heart Failure (CHF), and Atrial Fibrillation (AF)) with Normal Sinus Rhythm (NSR). The obtained features discriminate arrhythmia from NSR by p