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Analysis of loss of cooling accident in VVER-1000/V446 spent fuel pool using RELAP5 and MELCOR codes
Mousavian Seyed Khalil,Shirani Amir Saeed,Francesco D'Auria 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.8
Following the Fukushima nuclear disaster, the simulation of accidents in the spent fuel pool has become more noticeable. Despite the low amount of decay heat power, the consequences of the accidents in a spent fuel pool (SFP) can be severe due to the high content of long-lived radionuclides and lack of protection by the pressure vessel. In this study, the loss-of-cooling accident (LOFA) for the VVER-1000/V446 spent fuel pool is simulated by employing RELAP5 and MELCOR 1.8.6 as the best estimate and severe accident analysis codes, respectively. For two cases with different total power levels, decay heat of spent fuels is calculated by ORIGEN-II code. For modeling SFP of a VVER-1000, a qualified nodalizations are considered in both codes. During LOFA in SFP, the key sequences such as heating up of the pool water, boiling and reducing the water level, uncovering the spent fuels, increasing the temperature of the spent fuels, starting oxidation process (generating Hydrogen and extra power), the onset of fuel melting, and finally releasing radionuclides are studied for both cases. The obtained results show a reasonable consistency between the RELAP5 and MELCOR codes, especially before starting the oxidation process.
Interlocking joint shape optimization for structurally informed design of block assemblages
Mousavian Elham,Bagi Katalin,Casapulla Claudia 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.4
This paper presents a computer aided design tool that analyses the structural feasibility of interlocking assemblages with orthotropic sliding resistance and automatically adjusts the assemblage shape to remove the infeasibility. First, the static problem of limit analysis is extended to the corrugated interfaces. To model different bond patterns and openings, an assemblage is abstracted to different types of joints representing the dry joints between the blocks, joints inside the blocks, and the excluded joints where the openings are located. This problem is then reformulated to measure the structural infeasibility due to the sliding constraint violation. The so-called sliding infeasibility measure shows how far an infeasible model is to become feasible. This problem is used as the objective function of a shape optimization algorithm that minimizes the sliding infeasibility measure through automated change of the interlocking joints, by which the model becomes structurally feasible. The optimization is validated using the discrete element analysis.
Structurally informed design of interlocking block assemblages using limit analysis
Elham Mousavian,Claudia Casapulla 한국CDE학회 2020 Journal of computational design and engineering Vol.7 No.4
This paper presents a computational framework to design assemblages of interlocking blocks and to analyze their structural feasibility. The core of this framework is an extension of limit analysis to corrugated interfaces with orthotropic sliding behavior. Such block interfaces are made of a number of locks (i.e. projections on the corrugated faces, locking the blocks together) with rectangular cross section. The sliding resistance at the block interfaces is governed by the shear resistance of the locks and Coulomb’s friction law, normal to and along the locks, respectively. This resistance is assumed as a function of different interface geometric parameters and the stress state on an interface is represented by using a number of contact points distributed over the lock centerlines. The abstraction model has been validated through the comparison of the torsion–shear behavior of an interface obtained by the proposed model and experimental tests reported in the literature. The extended limit analysis has been implemented to model single-layer shells. When the model is infeasible, the geometry of the overall shell, blocks, and interlocking interfaces can be adjusted by the designer to make the model structurally feasible. The performance of the framework is presented through several examples, which demonstrate the relationships between the geometry of the interlocking interfaces and the stability of the assemblages.
R. Taherzadeh Mousavian,S. Behnamfard,A. Heidarzadeh,K. Taherkhani,R. Azari Khosroshahi,D. Brabazon 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.8
SiC ceramic nanoparticles were incorporated into the A356 aluminum matrix with different compositions using a combinationof stir casting and semisolid extrusion. The microstructure and mechanical properties of the produced nanocompositeswere evaluated. The results showed that the presence of Nickel acts as an appropriate metallic carrier for SiC nanoparticles,which causes uniform dispersion and spherical grains. Consequently, the coexistence of SiC nanoparticles and Nickelresulted in UTS of above 304 MPa and elongation of 5.8%. However, the addition of Titanium caused the formation offlake-like intermetallics, which decreased the elongation of the nanocomposites. The method introduced in this study forthe incorporation of SiC ceramic nanoparticles can be used as a promising process instead of conventional methods, whichare expensive and time-consuming.
Anisotropic high-field terahertz response of free-standing carbon nanotubes
Lee, Byounghwak,Mousavian, Ali,Paul, Michael J.,Thompson, Zachary J.,Stickel, Andrew D.,McCuen, Dalton R.,Jang, Eui Yun,Kim, Yong Hyup,Kyoung, Jisoo,Kim, Dai-Sik,Lee, Yun-Shik American Institute of Physics 2016 Applied Physics Letters Vol.108 No.24
Effect of crack location on buckling analysis and SIF of cracked plates under tension
Parham Memarzadeh,Sayedmohammad Mousavian,Mohammad Hosseini Ghehi,Tadeh Zirakian 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.35 No.2
Cracks and defects may occur anywhere in a plate under tension. Cracks can affect the buckling stability performance and even the failure mode of the plate. A search of the literature reveals that the reported research has mostly focused on the study of plates with central and small cracks. Considering the effectiveness of cracks on the buckling behavior of plates, this study intends to investigate the effects of some key parameters, i.e., crack size and location as well as the plate aspect ratio and support conditions, on the buckling behavior, stress intensity factor (SIF), and the failure mode (buckling or fracture) in cracked plates under tension. To this end, a sophisticated mathematical code was developed using MATLAB in the frame-work of extended finite element method (XFEM) in order to analyze the buckling stability and collapse of numerous plate models. The results and findings of this research endeavor show that, in addition to the plate aspect ratio and support conditions, careful consideration of the crack location and size can be quite effective in buckling behavior assessment and failure mode prediction as well as SIF evaluation of the cracked plates subjected to tensile loading.
Mohammad Irani,Ali Reza Keshtkar,Mohammad Ali Mousavian 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.10
Poly(vinyl alcohol)/tetraethyl orthosilicate (PVA/TEOS) ion exchange hybrid membranes modified with 3-mercaptopropyltrimethoxysilane (TMPTMS) were prepared by the sol-gel method, and their applications for the removal of lead ions from aqueous solutions in a batch sorption process were studied. The functional groups of the hybrid membranes were characterized by FTIR. Batch adsorption studies such as TMPTMS content, pH, adsorbent dose, contact time, initial concentration and temperature were evaluated. The maximum adsorption capacity of lead ions was found to be 61.62mg g−1, respectively. The kinetic data were analyzed by pseudo-first-order and pseudo-second-order kinetic models. The Freundlich and Langmuir isotherm models were applied to describe the equilibrium data. Thermodynamic parameters indicated that the lead adsorption onto the membrane is an endothermic and spontaneous process. The PVA/TEOS/TMPTMS hybrid membrane is regenerated by 0.5M HNO3/0.1 M HCl in equal ratio solution and the adsorption capacity did not change remarkably after five sorption-desorption cycles.
Saeed Abbasizadeh,Ali Reza Keshtkar,Mohammad Ali Mousavian 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4
Sorption of Cd(II), Ni(II) and U(VI) ions onto a novel cast PVA/TiO2/APTES nanohybrid adsorbent with variations in adsorbent dose, pH, contact time, initial metal concentration and temperature has been investigated. The adsorbent were characterized by SEM and FTIR analysis. BET surface area, pore diameter and pore volume of adsorbent were 35.98 m2 g-1, 3.08 nm and 0.059 cm3 g-1, respectively. The kinetic and equilibrium data were accurately described by the double-exponential and Freundlich models for all metals. The maximum sorption capacities were 49.0, 13.1 and 36.1 mg g-1 for Cd(II), Ni(II) and U(VI) ions with pH of 5.5, 5 and 4.5, respectively. Thermodynamic studies showed that the sorption process was favored at higher temperature. The adsorbent can be easily regenerated after 5 cycles of sorption–desorption.
Thompson, Zachary J.,Stickel, Andrew,Jeong, Young-Gyun,Han, Sanghoon,Son, Byung Hee,Paul, Michael J.,Lee, Byounghwak,Mousavian, Ali,Seo, Giwan,Kim, Hyun-Tak,Lee, Yun-Shik,Kim, Dai-Sik American Chemical Society 2015 NANO LETTERS Vol.15 No.9
<P>We demonstrate that high-field terahertz (THz) pulses trigger transient insulator-to-metal transition in a nanoantenna patterned vanadium dioxide thin film. THz transmission of vanadium dioxide instantaneously decreases in the presence of strong THz fields. The transient THz absorption indicates that strong THz fields induce electronic insulator-to-metal transition without causing a structural transformation. The transient phase transition is activated on the subcycle time scale during which the THz pulse drives the electron distribution of vanadium dioxide far from equilibrium and disturb the electron correlation. The strong THz fields lower the activation energy in the insulating phase. The THz-triggered insulator-to-metal transition gives rise to hysteresis loop narrowing, while lowering the transition temperature both for heating and cooling sequences. THz nanoantennas enhance the field-induced phase transition by intensifying the field strength and improve the detection sensitivity via antenna resonance. The experimental results demonstrate a potential that plasmonic nanostructures incorporating vanadium dioxide can be the basis for ultrafast, energy-efficient electronic and photonic devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2015/nalefd.2015.15.issue-9/acs.nanolett.5b01970/production/images/medium/nl-2015-01970q_0007.gif'></P>