A novel approach to measuring fluid saturation using X-ray computed tomography

Sheikhi Sobhan,Burukhin Alexander,Cheremisin Alexey 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.11

Digital rock analysis using X-ray computer tomography (CT scan) is an ongoing topic for studying the porous media in geothermal, natural gas, and petroleum industries. This study provides a novel approach to calculating fluid saturation in low permeability cores utilizing X-ray computed tomography. In the present study, synthetic low permeability cores were used to analyze two-phase saturation at atmospheric pressure and temperature. In the experiments, no dopant was used for visualizing different phases. As a novelty of the paper, PHREEQC geochemical software was employed to verify the saturation of X-ray CT scanning through modeling the geochemical reaction between aqueous and gaseous phases. This study presents a novel and reliable approach to verify the saturation of X-ray CT scan through geochemical modeling. The results of this study also prove that using the saturation of mass balance as the initial condition of the geochemical modeling leads to an excellent agreement between the saturation of CT scan and geochemical modeling. According to the results obtained, there is a 24% difference between gas saturation in CT scan and mass balance method, while such discrepancy is only 13% between gas saturation in CT scan and geochemical modeling.

A hybrid imperialist competitive ant colony algorithm for optimum geometry design of frame structures

Sheikhi, Mojtaba,Ghoddosian, Ali Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.46 No.3

This paper describes new optimization strategy that offers significant improvements in performance over existing methods for geometry design of frame structures. In this study, an imperialist competitive algorithm (ICA) and ant colony optimization (ACO) are combined to reach to an efficient algorithm, called Imperialist Competitive Ant Colony Optimization (ICACO). The ICACO applies the ICA for global optimization and the ACO for local search. The results of optimal geometry for three benchmark examples of frame structures, demonstrate the effectiveness and robustness of the new method presented in this work. The results indicate that the new technique has a powerful search strategies due to the modifications made in search module of ICACO. Higher rate of convergence is the superiority of the presented algorithm in comparison with the conventional mathematical methods and non hybrid heuristic methods such as ICA and particle swarm optimization (PSO).

Study of the Ribavirin drug adsorption on the surfaces of carbon nanotube and graphene nanosheet using density functional theory calculations

Sheikhi Masoome,Shahab Siyamak,Balali Ebrahim,Alnajjar Radwan,Kaviani Sadegh,Khancheuski Maksim,Al Saud Sultan 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.11

Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations were performed in the solvent water for the study of the adsorption of the Ribavirin (RIB) on surfaces of the carbon nanotube (CNT) and graphene nanosheet (GNS). After the adsorption, the electronic properties of the CNT and GNS change. The adsorption energies are shown the strong adsorption in GNS/RIB (0.816 eV) rather than CNT/RIB (0.544 eV). The dipole moment of CNT and GNS changes with the adsorption of the RIB from 0.00 to 4.57 and 7.05 Debye in CNT/RIB and GNS/RIB, respectively. The adsorption of the RIB molecule on CNT and GNS increases the value of λmax. The localized orbital locator and electron location function values for the C C bond confirm the stronger interaction between carbon atoms of GNS and RIB. Based on the results, it is suggested that GNS with a lower energy gap (3.03 eV) is a more suitable structure for adsorption of the RIB in comparison with the CNT (3.021).

Theoretical Study of the Resveratrol Adsorption on B12N12 and Mg-Decoration B12N12 Fullerenes

Sheikhi Masoome,Azarakhshi Fatemeh,Tafreshi Elnaz Sarabadani,Kaviani Sadegh,Shahab Siyamak,Ahmadianarog Mahin 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.6

The adsorption of Resveratrol (RSV) drug on surfaces of the pure B12N12 and Mg-decoration B12N12 fullerenes at physiological PH was studied using density functional theory and time-dependent density functional theory methods at the B3PW91/6-31+G* level at T = 298.15 K and 1 atm in the solvent (water) with a dielectric constant of 78.4. The adsorption energy (Eads) of RSV on two fullerenes have investigated through hydroxyl (-OH) groups. The adsorption effect of the RSV on the bond lengths, electronic properties, UV spectra, and excited states of B12N12 and Mg-B12N12 is detected. Natural bond orbital analysis shows a charge transfer between the RSV and two fullerenes. The electron location function (ELF) and localized orbital locator (LOL) values show that interaction between reactive atoms of RSV (O atoms) and B atom of B12N12 are an electrostatic and partially covalent character. The study interaction of RSV with the B12N12 and Mg-decoration B12N12 can be used in the field of drug delivery and adsorption on metal surfaces.

Letters to the Editor : Autohemotherapy in Chronic Urticaria: What Could Be the Autoreactive Factors and Curative Mechanisms?

( Abdolkarim Sheikhi ),( Mohsen Azarbeig ),( Hamid Karimi ) 대한피부과학회 2014 Annals of Dermatology Vol.26 No.4

Optimization of spring back in U-die bending process of sheet metal using ANN and ICA

Mojtaba Sheikhi Azqandi,Navid Nooredin,Ali Ghoddosian 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.65 No.4

The controlling and prediction of spring back is one of the most important factors in sheet metal forming processes which require high dimensional precision. The relationship between effective parameters and spring back phenomenon is highly nonlinear and complicated. Moreover, the objective function is implicit with regard to the design variables. In this paper, first the influence of some effective factors on spring back in U-die bending process was studied through some experiments and then regarding the robustness of artificial neural network (ANN) approach in predicting objectives in mentioned kind of problems, ANN was used to estimate a prediction model of spring back. Eventually, the spring back angle was optimized using the Imperialist Competitive Algorithm (ICA). The results showed that the employment of ANN provides us with less complicated and time-consuming analytical calculations as well as good results with reasonable accuracy.

A hybrid imperialist competitive ant colony algorithm for optimum geometry design of frame structures

Mojtaba Sheikhi,Ali Ghoddosian 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.46 No.3

This paper describes new optimization strategy that offers significant improvements in performance over existing methods for geometry design of frame structures. In this study, an imperialist competitive algorithm (ICA) and ant colony optimization (ACO) are combined to reach to an efficient algorithm, called Imperialist Competitive Ant Colony Optimization (ICACO). The ICACO applies the ICA for global optimization and the ACO for local search. The results of optimal geometry for three benchmark examples of frame structures, demonstrate the effectiveness and robustness of the new method presented in this work. The results indicate that the new technique has a powerful search strategies due to the modifications made in search module of ICACO. Higher rate of convergence is the superiority of the presented algorithm in comparison with the conventional mathematical methods and non hybrid heuristic methods such as ICA and particle swarm optimization (PSO).

Studying the effects of chain extenders chemical structures on the adhesion and mechanical properties of a polyurethane adhesive

H. Sheikhy,B. Ramezanzadeh,M. Shahidzadeh,F. Noroozi 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.6

Chain extenders including diethanol amine (DEA) and 2-cyano-N,N-bis-hydroxyethyl acetamide (CNBA)were utilized to enhance the adhesion and mechanical properties of a polyurethane (PU) adhesive. The adhesion and mechanical properties of the adhesives were studied by peel test, tensile test and dynamic thermal analysis (DMTA) respectively. Results revealed that both chain extenders (DEA and CNBA)increased peel test modulus. The cross-linking density and toughness of the adhesive were significantly increased using chain extenders. Results showed that chain extender without side chain (DEA) could improve the adhesion and mechanical properties of the adhesive greater than chain extender with aliphatic side group (CNBA).

Dietary Antioxidant Capacity and Its Association with Preeclampsia

( Mahdiyeh Sheikhi ),( Elham Sharifi-zahabi ),( Zamzam Paknahad ) 한국임상영양학회 2017 Clinical Nutrition Research Vol.6 No.1

Preeclampsia (PE) is one of the major disorders in pregnancy leading to many adverse maternal outcomes. Although the etiology of PE is not fully understood, resent studies suggest that an imbalance between free radicals production and the antioxidant defense system might have key role. Our aim of the current study was to evaluate the association between dietary total antioxidant capacity (TAC), serum TAC and risk of PE in women with preeclampsia and normal pregnancy. This case-control study conducted on 55 women with preeclampsia and 93 with normal pregnancy. Dietary intakes were obtained by a semi-quantitative food frequency questionnaire (FFQ) with 168 itmes. Dietary TAC was assessed according to United States Department of Agriculture (USDA) Database for oxygen radical absorbance capacity (ORAC), Release 2. Serum TAC was measured by a double-antibody sandwich enzyme-linked immunesorbent assay (ELISA). After adjusting for energy, pre-pregnant body mass index (BMI) and history of PE, no relationship was found between intake of hydrophilic-ORAC (H-ORAC), lipophilic-ORAC (L-ORAC), total phenolics (TP), total-ORAC (T-ORAC), and PE risk. However, serum TAC had a significant positive relationship with the risk of PE after adjusting for energy (odds ratio [OR], 0.07; 95% confidence interval [CI], 0.16-0.35), BMI and history of PE (OR, 0.04; 95% CI, 0.01-0.32). Findings of this study indicate that serum TAC is positively associated with the risk of PE but no association was found between intake of antioxidant indices and PE risk.

Natural Rubber Bearing Incorporated with Steel Ring Damper (NRB-SRD)

Javad Sheikhi,Mojtaba Fathi 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.1

The present paper is aimed to investigate the behavior of Natural Rubber Bearing incorporated with steel ring damper (NRBSRD). These types of dampers are integrated of several steel rings which are considered with two confi gurations namely, continual steel ring damper and separate steel ring damper and are inserted between top and bottom plates. The performance characteristics of the system such as eff ective horizontal stiff ness, energy dissipation, equivalent viscous damping and residual deformation are calculated and then compared with the results of high damping rubber bearings and also shape memory alloy (SMA)-lead core rubber bearing (SMA-LRB). The results show that the energy dissipation in steel rings are mainly based on plastic deformation due to fl exural behavior of the rings. NRB-SRD shows better performance in energy dissipation comparing to SMA-LRB and HDRB. These additional dampers show higher stability and energy dissipation in low shear strains due to developing of link between structure and substructure having desirable initial stiff ness under weak earthquakes and wind loads and also in higher shear strains due to creation of higher energy dissipation, stability and secondary stiff ening.