Gas injection in fractured reservoirs : emphasis on mass transfer

Mass transfer occurs in a number of Enhanced Oil Recovery (EOR) processes such as gas injection, solvent injection, Water Alternative Gas injection (WAG) processes and gas cycling. The role of mass transfer in gas injection into an oil phase at fractured media is significant. In naturally fractured reservoirs, fluid exists in two interconnected systems; the rock matrix, which contains the bulk of the volume of the oil reservoir, and the high permeability fractures medium.Laboratory measurements of the diffusion coefficient of methane into crude oil under both unsteady-state and steady-state conditions were carried out to obtain the dissolution rates of methane during gas injection and/or flooding in the short term, and for enhanced oil recovery at thermodynamic equilibrium in the long term. The pressure drop in the core flooding cell during the contact of the methane and oil phases was used to measure the diffusion coefficient of the system under the reservoir conditions. A new empirical correlation for the diffusion coefficient was achieved using the measured experimental data at reservoir conditions. A comparison of this new correlation and previous methods shows that the current method is more accurate than other methods at high pressure and temperature conditions.Experimental tests on fluid flow in tight carbonate porous media were carried out with single and composite core plugs. It was demonstrated that the swelling of oil strongly depended on the contact time of the oil and gas phases and heterogeneity of the system.The two and three-phase relative permeability in tight carbonate reservoirs was a major part of this research. It was carried out on single and composite core plugs at reservoir conditions. Modelling of the displacement of fluids in tight carbonate rocks was carried out with experimental data. Solving of the partial differential equation of displacement phenomena in porous media was carried out with the finite element method software (FLEXPDE). All of the experimental data with the new diffusion coefficient correlation were used to model the system.In the fracture medium, an artificial fracture in synthetic rock was made and all the parameters used for carbonate rock were considered without fracture. Modelling of the system was carried out between the matrix and fracture medium. The effect of mass transfer between gas in the fracture and oil in the matrix was evaluated and the variation of saturation in the matrix by applying the boundary condition method was evaluated. As a result, it was shown that the mass transfer significantly increased the recovery from the matrix by following the condensation and evaporation mechanisms

Comparing Inferior Oblique Muscle Myectomy with and without Displacement of Bilateral Rectus Muscles in Correction of Exotropia V Pattern with Severe Inferior Oblique Muscle Overreaction: A Pilot Study

Purpose: To evaluate a new method of inferior oblique muscle myectomy with displacement of the external rectus muscles on both sides for correction of exotropia V pattern with severe inferior oblique muscle overaction.Patients and Methods: In a pilot study, 9 patients with exotropia V pattern strabismus who were referred to Al-Zahra Ophthalmology Hospital, Tehran, Iran, in 2011 were studied in two randomly divided groups: group A underwent conventional surgical treatment including external rectus resection and inferior oblique weakening and in addition received external rectus displacement upwards while group B only received the conventional treatment. Results:  The mean V pattern before surgery in group A was 41 ± 16.7 prism diopters which changed to 6 ± 10.7 prism diopters after surgery. The mean V pattern before surgery in group B was 37.2 ± 4.3 prism diopters which changed to 19.5 ± 3.1 prism diopters after surgery. In group A, V-pattern correction was 35.0 ± 11.6 prism diopters while it was  20.2 ± 1.2 prism diopters in group B, which indicated a statistically significant difference between the two groups (P = 0.04(.Conclusion: Our results suggest that the mean V Pattern correction among patients undergoing our modified surgical method was significantly higher than the conventional method. Further comparative studies with a higher number of participants are suggested to confirm our results

Voltammetric folic acid sensor based on nickel ferrite nanoparticles modified-screen printed graphite electrode

In this study, an electrochemical sensor for the quantification of folic acid with voltam­metric detection in physiological conditions was constructed. For this purpose, nickel ferrite (NiFe2O4) nanoparticles were used to modify the surface of a screen-printed graphite electrode (NiFe2O4/SPGE) and applied in the determination of folic acid. The modified electrode displays a strong electrochemical response to folic acid. Folic acid was determined electrochemically using the differential pulse voltammetry (DPV) technique with a detection limit of 0.09±0.001 µM in 0.2–147.0 µM linear range in phosphate buffer solution (PBS) at pH 7.0 with this NiFe2O4/SPGE sensor, which has the best electron transfer rate. Also, the sensitivity of the modified electrode was obtained as 0.1139 µA µM-1. The NiFe2O4/SPGE sensor was successfully applied for the determination of folic acid in real samples

An Investigation into the English Language Needs of Bank Employees of Saderat Bank in Mashhad

With the increase in marketing and trading, recognition of the need for improved English communication skills has been growing among Banking professionals. Need analysis is a chief point to consider in English for Specific Purposes (ESP ) courses for syllabus design and materials development. This study was done in order to understand to what extend Bank employees of Saderat bank in Mashhad  need to use English at the present time and future and also to find out what problems in using English they have during their work This research was done in Saderat Banks in Mashhad, in some parts of the central office such as: management department, inspection department, financial marketing and 10 branches with Foreign Exchange departments, Accounting department, Transfer department and Loan department. The participants included 70 bank employees with different job positions. They were asked to answer a questionnaire which included 33 closed questions and 1 open-ended question to identify English skills that they need in their job, the problems they have in using English and their desire for taking an English training course. Based on the data analysis it became clear that they need speaking skill the most and they have problems with all the skills. They stated that Bank should provide English training courses for them

Distribution of Enterotoxigenic Escherichia coli among E. coli isolates from diarrheal samples referred to educational hospitals in Tehran-Iran

Background: Introduction: Enterotoxigenic Escherichia coli (ETEC) is the most important bacterial cause of watery  travelers' diarrhea  in  developing countries. Watery diarrhea is can cause serious life-threatening dehydration. ETEC was caused diarrhea by the secretion of two heat-labile enterotoxins (LTs) and the heat-stable enterotoxins (STs) which increase intestinal secretion. Routine laboratory methods are not appropriate to detect ETEC and other diarrheagenic E. coli pathotypes. The molecular techniques such as PCR are rapid and accurate methods that have been developed for detection of ETEC. We were recognized ETEC by PCR on lt and st genes from E. coli isolates from patients with diarrhea collected from selected Tehran educational hospitals.Materials and Methods: The E. coli isolates were collected from total 140 patients with diarrhea and 110 patients without diarrhea using culture and IMViC test. DNA was extracted by boiling method and the presence of the uidA, lt and st genes was detected by PCR.Results: Among 140 E. coli isolates from diarrheal stools 5 (3.6%) isolates were positive for, just lt gene, 3 (2.1%) co-amplified for both lt/st and 1 (0.7%) was positive for just the st gene which were considered as ETEC. In the E. coli isolates from non-diarrheal control samples just one (0.9%) isolate was positive for both lt and st genes.Conclusion: The results showed that the ETEC as a significant cause of diarrhea, usually ignored by laboratories using traditional methods. Sometimes the ETEC causes severe diarrhea and can threaten for patient's life. Thus a rapid diagnostic test such as PCR can be very helpful in the treatment of patients

cGAN-Based High Dimensional IMU Sensor Data Generation for Therapeutic Activities

Human activity recognition is a core technology for applications such as rehabilitation, ambient health monitoring, and human-computer interactions. Wearable devices, particularly IMU sensors, can help us collect rich features of human movements that can be leveraged in activity recognition. Developing a robust classifier for activity recognition has always been of interest to researchers. One major problem is that there is usually a deficit of training data for some activities, making it difficult and sometimes impossible to develop a classifier. In this work, a novel GAN network called TheraGAN was developed to generate realistic IMU signals associated with a particular activity. The generated signal is of a 6-channel IMU. i.e., angular velocities and linear accelerations. Also, by introducing simple activities, which are meaningful subparts of a complex full-length activity, the generation process was facilitated for any activity with arbitrary length. To evaluate the generated signals, besides perceptual similarity metrics, they were applied along with real data to improve the accuracy of classifiers. The results show that the maximum increase in the f1-score belongs to the LSTM classifier by a 13.27% rise when generated data were added. This shows the validity of the generated data as well as TheraGAN as a tool to build more robust classifiers in case of imbalanced data problem

Design of a Compact Neutron Detector with Flat Response in energy range from 5-20 MeV

One of the requirements of neutron detection in wide energy range is a detector with flat response. In this work, a compact neutron detector for energy range from 5-20 MeV has been introduced. The detector has two small spherical 3He proportional counters (PC) placed inside a cylindrical polyethylene moderator. Flat response (sensitivity) of the detector has been optimized according to the counters positions inside the moderator. Optimization carried out using MCNP4C Monte Carlo code and Artificial Neural Network (ANN). Results show that the flatness of the sensitivity response of the introduced detector has been increased compared to the conventional detectors

Dynamic response of ladder track rested on stochastic foundation under oscillating moving load

The ladder track is a new type of an elastically supported vibration-reduction track system that has been applied to several urban railways. This paper is devoted to the investigation of dynamic behavior of a ladder track under an oscillating moving load. The track is represented by an infinite Timoshenko beam supported by a random elastic foundation. In this regard, equations of motion for the ladder track are developed in a moving frame of reference. In continuation, by employing perturbation theory and contour integration, the response of the ladder track is obtained analytically and its results are verified using the stochastic finite element method. Finally, using the verified model, a series of sensitivity analyses are accomplished on effecting parameters including velocity and load frequency

Electrochemical sensor for determination of hydroxylamine using functionalized Fe3O4nanoparticles and graphene oxide modified screen-printed electrode

A simple strategy for determination of hydroxylamine based on Fe3O4nanoparticles function-nalized by [2-(4-((3-(trimethoxysilyl)propylthio)methyl)1-H1,2,3-triazol-1-yl)aceticacid] (FNPs) and graphene oxide (GO) modified screen-printed electrode (SPE), denoted as (Fe3O4FNPs/GO/SPE), is reported. The electrochemical behavior of hydroxylamine was investigated at Fe3O4FNPs/GO/SPE by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chro-noamperometry (CHA) techniques in phosphate buffer solution (pH 7.0). Fe3O4FNPs/GO/SPE as a novel electrochemical sensor exhibited catalytic activity toward the oxidation of hydroxylami-ne. The potential of hydroxylamine oxidation was shifted to more negative potentials, and its oxidation peak current increased on the modified electrode, also indicatingthat under these conditions,the electrochemical process is irreversible. The electrocatalytic current of hydroxyl-amine showed a good relationship in the concentration range of 0.05–700.0 μM, with a detection limit of 10.0 nM. The proposed electrode was applied for the determination of hydroxylamine in water samples, too