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RISS 인기검색어
- 검색키워드
- 저자 : Ahmed M. Hassan (검색결과 56 건)
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Numerical Study of Fan Coil Heat Exchanger with Copper-Foam
Ahmed M. Hassan,Adil Abbas Alwan,Hameed K. Hamzah 한국유체기계학회 2023 International journal of fluid machinery and syste Vol.16 No.1
Due to its high porosity as well as a high specific surface area, the use of open cell metallic foam in heat transfer applications has received increasing interest. In present study, the dynamic and thermal performance of heat exchanger composed of copper foam incorporated in a fan coil was numerically analyzed. Darcy-Brinkman-Forchheimer model was used to represent the momentum equation inside the metallic foam (a porous medium). A local thermal equilibrium was used to solve the energy equation through the porous medium. Different porosity values were taken during the study, ranging from 0.88 to 0.98, while the velocity of inlet air of the heat exchanger ranged from 1 m/s to 10 m/s. The objective of current study is to compare the thermal and dynamic performance of the heat exchanger affected by several variables such as heat transfer coefficient, friction factor, pressure drop, Colburn factor, and area goodness factor. The results showed that increasing the air inlet velocity will increase the heat transfer coefficient, but on the other hand, increasing the velocity ten times will rise pressure drop from 19.032 Pa to 335.76 Pa. Also, the area goodness factor value will decrease with increasing inlet velocity. Finally, we found that increasing in medium porosity will reduce heat transfer coefficient but increase pressure drop
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Microwave-assisted synthesis of novel porous organic polymers for effective selective capture of CO2
Ahmed M. Alloush,Hamza Abdulghani,Hassan A. Amasha,Tawfik A. Saleh,Othman Charles S. Al Hamouz 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.113 No.-
Performing carbon dioxide (CO2) capture in an environmentally benign and cost-effective way is challengingowing to several factors including selectivity. Thus, the development of polymers that providehigh capacity and selectivity for the removal of CO2 gas is important. N-based porous polymers arepromising for CO2 capture due to their abundant porosity, variable surface characteristics, and great stability. Herein, porous organic polymers were synthesized by microwave-assisted Freidel-Crafts alkylationof 2,20-bipyridine and pyrrole with dimethoxymethane as a cross-linker. The synthesized polymers werecharacterized by Fourier transform infrared, nuclear magnetic resonance, thermogravimetric analyzers,and surface analyzers based on Brunauer–Emmett–Teller theory (BET). The porous polymers exhibitedhigh surface areas of 580 – 930 m2/g. The polymers showed high ideal adsorbed solution theory (IAST)selectivity of 53 – 63 toward CO2 over N2 at 1 bar and 298 K under flue gas composition. Whereas theselectivity toward CO2 over CH4 at 1 bar and 298 K under natural gas composition was 12 – 18. The synthesizedpolymers achieved exceptional H2O adsorption capacity at P/P0 = 0.9 and 293 K of 35 – 45 mmol/g. The results reveal the polymers provide promising candidates for the CO2 capture from various mixtures,such as flue gas and natural gas.
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Management of Charcoal Rot of Sesame by Seed Soaking in Medicinal Plant Extracts and Hot Water
Ahmed, Hoda A.M.,Abdel-Razik, A.A.,Hassan, M.H.A.,Khaled, S.A. The Korean Society of Plant Pathology 2010 Plant Pathology Journal Vol.26 No.4
Macrophomina phaseolina causing charcoal rot was isolated from sesame seeds (cvs. Giza 32 and Shandawel-3) collected from different localities of Assiut, Sohage and El-Minia Governorates. The fungus was found in the highest frequently in samples collected from Assiut Governorate followed by Sohag and finally EL Minia Governorate. The obtained isolates were different in their virulence on the tested sesame cvs. Also, they differed in their growth nature including colony color and sclerotial production. The color of colonies of the pathogen seem to be correlated with density of sclerotial formation. Aqueous extracts of Majorna, Wild chamomile, Geranium oil and Nees plants were highly toxic to tested isolates of M. phaseolina, in vitro. On the other hand the rest of the tested aqueous extracts had no effect. Under greenhouse conditions in 2005 and 2006 seasons, soaking seeds of sesame before sowing in aqueous extracts of Eucalyptus, Nerium, Ocimum and Roesmary plants decreased the disease incidence. Aqueous extracts of Eucalyptus and Ocimum were the most effective treatment. Dipping sesame seeds in hot water at $60^{\circ}C$ for 5 minutes increased seed germination of Giza 32 and Shandawel-3 cvs. followed by $55^{\circ}C$, $50^{\circ}C$ and $45^{\circ}C$, while $40^{\circ}C$ treatment resulted the lowest seed germination rate. Dipping sesame seeds in hot water at different temperature before planting decreased seed, seedling and charcoal rots. Soaking seeds in hot water at $60^{\circ}C$ increased greatly plant height and decreased seed, seedling rot and charcoal rot followed by $55^{\circ}C$ and $50^{\circ}C$, under greenhouse condition.
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Management of Charcoal Rot of Sesame by Seed Soaking in Medicinal Plant Extracts and Hot Water
Hoda A. M. Ahmed,A. A. Abdel-Razik,M. H. A. Hassan,S. A. Khaled 한국식물병리학회 2010 Plant Pathology Journal Vol.26 No.4
Macrophomina phaseolina causing charcoal rot was isolated from sesame seeds (cvs. Giza 32 and Shandawel-3)collected from different localities of Assiut, Sohage and El-Minia Governorates. The fungus was found in the highest frequently in samples collected from Assiut Governorate followed by Sohag and finally EL Minia Governorate. The obtained isolates were different in their virulence on the tested sesame cvs. Also, they differed in their growth nature including colony color and sclerotial production. The color of colonies of the pathogen seem to be correlated with density of sclerotial formation. Aqueous extracts of Majorna, Wild chamomile,Geranium oil and Nees plants were highly toxic to tested isolates of M. phaseolina, in vitro. On the other hand the rest of the tested aqueous extracts had no effect. Under greenhouse conditions in 2005 and 2006seasons, soaking seeds of sesame before sowing in aqueous extracts of Eucalyptus, Nerium, Ocimum and Roesmary plants decreased the disease incidence. Aqueous extracts of Eucalyptus and Ocimum were the most effective treatment. Dipping sesame seeds in hot water at 60oC for 5 minutes increased seed germination of Giza 32 and Shandawel-3 cvs. followed by 55 oC, 50oC and 45oC, while 40oC treatment resulted the lowest seed germination rate. Dipping sesame seeds in hot water at different temperature before planting decreased seed,seedling and charcoal rots. Soaking seeds in hot water at 60oC increased greatly plant height and decreased seed,seedling rot and charcoal rot followed by 55oC and 50oC, under greenhouse condition.
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Asaad. F. Hassan,Laila M. Alshandoudi,Aya M. Awad,Ahmed A. Mustafa,Ghada Esmail 한국고분자학회 2023 Macromolecular Research Vol.31 No.7
In the current study, a novel nanomaterial called nanomagnetite/copper oxide/potassium carrageenan nanocomposite (MKCO) was fabricated to include Fenton (nanomagnetite, NM) and Fenton-like reagent (copper oxide nanoparticles, NCO) in a matrix of potassium carrageenan biopolymer. The prepared solid materials were characterized by different physicochemical techniques, such as TGA, N2 adsorption/desorption, SEM, TEM, XRD, DRS, pHPZC, and FTIR. The prepared MKCO showed unique properties like higher specific surface area of 652.50 m2/g, pore radius of 1.19 nm, pHPZC equals 7.80, and the presence of different surface chemical functional groups. Under various application conditions, comparative experiments between Safranin-O dye (SO) adsorption and Photo-Fenton catalytic degradation were conducted. After 24 h, MKCO had a maximum adsorption capacity of 384.61 mg/g at 42 °C, while the Photo-Fenton oxidation process took only 10 min to totally decompose 93% of SO at 21 °C. Based on the higher values of correlation coefficients, Langmuir’s adsorption model is the best-fitted adsorption model for SO onto all the prepared solid materials. Studies on SO adsorption’s kinetics and thermodynamics show that it is physisorption and that it operates according to endothermic, spontaneous, and PFO model processes. While, PFO, endothermic, and non-spontaneous processes are satisfied by the catalytic decomposition of SO. After five application cycles, MKCO demonstrated good catalyst reusability with a 3.4% decrease in degrading efficiency. For lower contaminant concentrations and shorter application times, Photo-Fenton catalytic degradation of organic pollutants is more effective than adsorption.
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Rashid Ali Sindhu,M.K.Park,Saemahn Bhak,Behzad Ahmed Zai,Hassan Mehboob,Joongwon Lee 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Residual stresses deteriorate strength of materials adversely affecting quality of industrial products. A removable or a reduction of the residual stresses is an essential procedure in successful product developments. Effective and convenient methods are necessary for detection and evaluation of the residual stresses. In this investigation Hole Drilling Method is chosen for identification and a quantitative determination of the residual stresses of specimen in two groups under different laser welding speed conditions, 4.1 m/min and 5.1 m/min. Laser lap welding of SPCC sheet joints was investigated along the welding line at two locations, at the welding middle and end locations in the heat affected zone (HAZ). Based on the experimental results and the analysis, higher welding speed condition is predicted to reduce the residual stresses.
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Mahmoud T. Nawar,Ehab B. Matar,Hassan M. Maaly,Ahmed G. Alaaser,Osman Hamdy 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.88 No.1
This paper handles the results of an extensive parametric study on the rotational stiffness of the flexible base connection using ABAQUS program. The results of the parametric study show the relation between the applied moment and the relative rotation for 96 different base connections. The configurations of the studied connections considered different numbers, diameters, and spacing of the anchor bolts along with different thicknesses of the base plate to investigate the effect of these parameters on the rotational stiffness behavior. The results of the previous parametric research used through the whale optimization algorithm (WOA) to detect different equation formulation of the moment-rotation (M-Ɵr) equation to detect optimum equation simulates the general nonlinear rotational behavior of the flexible base connection considering all variables used in the parametric study. WOA is a relatively new promising algorithm, which is used in different types of optimization problems. For more verification, the classical genetic algorithm (GA) is used to make a comparison with WOA results. The results show that WOA is capable of getting an optimum equation of the M-Ɵr relation, which can be used to simulate the actual rotational stiffness of the flexible base connections. The rotational stiffness at H/150 can be calculated using WOA (1) method and be used as a design aid for engineering design.
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Ahmed H. M. Findi,Mohammad H. Marhaban,Raja Kamil,Mohd Khair Hassan 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.2
The problem of determining a smooth and collision-free path with maximum possible speed for a Mobile Robot (MR) which is chasing a moving target in a dynamic environment is addressed in this paper. Genetic Network Programming with Reinforcement Learning (GNP-RL) has several important features over other evolutionary algorithms such as it combines offline and online learning on the one hand, and it combines diversified and intensified search on the other hand, but it was used in solving the problem of MR navigation in static environment only. This paper presents GNP-RL based on predicting collision positions as a first attempt to apply it for MR navigation in dynamic environment. The combination between features of the proposed collision prediction and that of GNP-RL provides safe navigation (effective obstacle avoidance) in dynamic environment, smooth movement, and reducing the obstacle avoidance latency time. Simulation in dynamic environment is used to evaluate the performance of collision prediction based GNP-RL compared with that of two state-of-the art navigation approaches, namely, Q-Learning (QL) and Artificial Potential Field (APF). The simulation results show that the proposed GNP-RL outperforms both QL and APF in terms of smooth movement and safer navigation. In addition, it outperforms APF in terms of preserving maximum possible speed during obstacle avoidance.
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