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240 results on '"Sadeghi, Morteza"'

1. Optimizing Near Field Computation in the MLFMA Algorithm with Data Redundancy and Performance Modeling on a Single GPU

Author

Sadeghi, Morteza and Torabi, Abdolreza

Subjects
Computer Science - Distributed, Parallel, and Cluster Computing, Computer Science - Performance, Physics - Computational Physics
Abstract

The Multilevel Fast Multipole Algorithm (MLFMA) has known applications in scientific modeling in the fields of telecommunications, physics, mechanics, and chemistry. Accelerating calculation of far-field using GPUs and GPU clusters for large-scale problems has been studied for more than a decade. The acceleration of the Near Field Computation (P2P operator) however was less of a concern because it does not face the challenges of distributed processing which does far field. This article proposes a modification of the P2P algorithm and uses performance models to determine its optimality criteria. By modeling the speedup, we found that making threads independence by creating redundancy in the data makes the algorithm for lower dense (higher frequency) problems nearly 13 times faster than non-redundant mode.

Published
2024

3. Ionic Transport and Selectivity of Electrokinetically-Actuated Non-Newtonian Flows within a pH-Regulated Rectangular Nanochannel

Author

Vakili, Mohammad Ali, Sadeghi, Morteza, Saidi, Mohammad Hassan, and Moosavi, Ali

Subjects
Physics - Fluid Dynamics, Physics - Applied Physics, Physics - Chemical Physics
Abstract

In the present study, the ionic transport and selectivity of electrokinetically-driven flow of power-law fluids in a long pH-regulated rectangular nanochannel are analyzed. The electrical potential and momentum equations are numerically solved through a finite difference procedure for a non-uniform grid. Non-linear Poisson-Boltzmann equation along with the association/dissociation reactions on the surface is considered. In addition, numerical simulations with the finite element method in 3D space are performed to compare the results with those obtained from 2D analysis. Moreover, an analytical solution under Debye-H\"uckel approximation for the limiting case of a slit nanochannel is derived and its results are compared with those obtained from numerical simulations. It is shown that the channel aspect ratio can influence all the physicochemical parameters. It is observed that the mean velocity and the convective ionic conductance are strong descending functions of the flow behavior index. By investigating the non-Newtonian fluid behavior effect, it is revealed that its impact on the ionic conductance becomes significant at high values of the solution pH and its variation can alter the anionic transport direction inside the nanochannel. Moreover, it is shown the flow behavior index can strongly influence the ion selectivity of the nanochannel and its variation can be used to let the selectivity go through its maximum as a function of pH., Comment: 51 pages, 14 figures

Published
2021

15. Influence of solvent, Lewis acid-base complex, and nanoparticles on the morphology and gas separation properties of polysulfone membranes

Author

Maghami, Saeid, Sadeghi, Morteza, Baghersad, Samaneh, and Zomoza, Beatriz

Subjects
Polysulphones -- Chemical properties, Membranes (Technology) -- Chemical properties, Solvents -- Chemical properties, Chemical reactions -- Observations, Engineering and manufacturing industries, Science and technology
Abstract

A series of polysulfone (PSF) membranes were prepared using different solvents: dimethylformamide (DMF), tetrahydrofuran, dimethylacetamide, and n-methyl-2-pyrrolidone (NMP). The PSF membrane prepared by NMP showed the highest gas permeability. The influence of propionic acid as a Lewis acid on gas separation properties of the PSF was explored. The PSF membrane prepared by the casting solution containing 25 wt% PSF, 35 wt% propionic acid, and 40 wt% NMP showed a superior gas separation performance. The gas permeation measurements indicated that incorporating 30 wt % [gamma]-alumina nanoparticles into the PSF matrix resulted in about the respective 43% and 41% increase in C[O.sub.2] and [O.sub.2] permeability together with a rise in C[O.sub.2]/ C[H.sub.4] and [O.sub.2]/[N.sub.2] selectivities (13% and 7%, respectively). Furthermore, by rearranged modified Maxwell model, the role and nature of the interfacial layer in the PSF-based mixed matrix membranes were mathematically analyzed considering a reduced permeability factor. KEYWORDS gas separation, Lewis acid-base complex, mixed matrix membranes, polysulfone membranes, solvent effect, 1 | INTRODUCTION Global warming due to C[O.sub.2] emission into the atmosphere, and production of clean and conventional energies ([H.sub.2] and C[H.sub.4], respectively) has attracted great attention to the need [...]

Published
2021
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34. Vibro-fluidized bed heat pump drying of mint leaves with respect to phenolic content, antioxidant activity, and color indices

Author

Ataei Ardestani Seyed Majid, Sadeghi Morteza, Beheshti Babak, Minaei Saeid, and Hamdami Naser

Subjects
drying kinetics, fluidized bed drying, moisture diffusivity, pharmaceutical plants, Chemical engineering, TP155-156, Chemical industries, HD9650-9663
Abstract

Because of high porosity and stickiness of mint leaves, they could not be fluidized well during fluidization. In this study, a vibro-fluidized bed dryer assisted heat pump system was designed and fabricated to overcome this problem. The drying experiments were carried out at temperatures of 40, 50 and 60 °C. The quality of the dehydrated samples was assessed based on color indices, antioxidant activity, and total phenolic content. Drying process primarily occurred in falling rate period. The effective coefficient of moisture transfer of the samples was increased with air temperature and varied from 4.26656×10-11 to 2.95872×10-10 m2 s-1 for heat pump drying (HPD) method, and 3.71918×10-11 to 1.29196×10-10 m2 s-1 for none-heat pump drying (NHPD) method. The color indices for temperatures of 40 and 50 °C were very close to each other, whereas by increasing temperature to 60 °C, a remarkable loss of green color was observed. The highest phenolic content was found in methanolic extract for HPD at 60 °C, and NHPD at 50 °C contained the lowest amount of phenolic compounds. NHPD treatments showed lower antioxidant activity compared to HPD treatments at the same temperature due to the longer drying times.

Published
2015
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