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- 저자 : Khalil Ahmed (검색결과 61 건)
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Maximum Power Point Tracking Controller Connecting PV System to Grid
Ahmed G. Abo-Khalil,Dong-Choon Lee,Jul-Ki Seok,Jong-Woo Choi,Heung-Geun Kim 전력전자학회 2004 ICPE(ISPE)논문집 Vol.- No.-
The photovoltaic generators have a nonlinear V-I characteristics and maximum power points which vary with the illumination level and temperature. Using maximum power point tracker(MPPT) with the intermediate converter can increase the system efficiency by matching the PV systems to the load. This paper presents a maximum power point tracker based on fuzzy logic and a control scheme for a singlephase inverter connected to the utility grid. The fuzzy logic<br/> controller(FLC) provides an adaptive nature for the system performance. Also the FLC provides excellent features such<br/> as fast response, good performance and the ability to change the fuzzy parameters to improve control system. The singlephase dc/ac inverter is used to connect the PV system to the grid utility and local loads, of which control scheme is implemented to inject the PV output power to the utility grid at unity power factor and reduced harmonic level. The simulation results have shown the effectiveness of the proposed scheme.
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Maximum Power Point Tracking Controller Connecting PV System to Grid
Ahmed G. Abo-Khalil,Dong-Choon Lee,Jong-Woo Choi,Heung-Geun Kim 전력전자학회 2006 JOURNAL OF POWER ELECTRONICS Vol.6 No.3
Photovoltaic (PV) generators have nonlinear V-I characteristics and maximum power points which vary with illumination level and temperature. Using a maximum power point tracker (MPPT) with an intermediate converter can increase the system efficiency by matching the PV systems to the load. This paper presents a maximum power point tracker based on fuzzy logic and a control scheme for a single-phase inverter connected to the utility grid. The fuzzy logic controller (FLC) provides an adaptive nature for system performance. Also the FLC provides excellent features such as fast response, good performance and the ability to change the fuzzy parameters to improve the control system. A single-phase AC-DC inverter is used to connect the PV system to the grid utility and local loads. While a control scheme is implemented to inject the PV output power to the utility grid at unity power factor and reduced harmonic level. The simulation results have shown the effectiveness of the proposed scheme.
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Khalil Ahmed,Nudrat Zahid Raza,Farzana Habib,Muhammad Aijaz,Muhammad Hayat Afridi 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.6
In this article, polypropylene reinforced marble sludge (PP/MS) was prepared, and the effects of MS loading and polypropylene-g-maliec anhydride (PP-g-MAH) as compatibilizer on density, melt flow index (MFI), and mechanical properties of PP/MS composite were investigated. Our studies show that tensile strength, flexural strength and tensile modulus increased with increasing the MS loading but tensile strength increased till 30 pph of MS further addition of MS in PP composites decreased the strength. The % elongation at break and Izod Impact Strength decreased with increasing of MS loading. Studies revealed that PP/MS composites containing PP-g-MAH enhance the properties compared to without compatibilizer.
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Ahmed G. Abo-Khalil,Dong-Choon Lee 전력전자학회 2006 전력전자학술대회 논문집 Vol.- No.-
A novel online capacitance estimation method for a DC-link capacitor in a three-phase AC/DC/AC PWM converter is proposed. A controlled AC voltage with a lower frequency than the line frequency is injected into the DC-link voltage, which then causes AC power ripples at the DC output side. By extracting the AC voltage and power components on the DC output side using digital filters, the capacitance can then be calculated using the recursive least squares method. The proposed method can be simply implemented with only software and no additional hardware. Experimental results confirm that the estimation error is less than 0.2%.
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Khalil Ahmed,Shaikh Sirajuddin Nizami,Nudrat Zahid Raza 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.4
This paper discusses an extensive overview of characterization of marble sludge (MS) with carbon black (CB) and rice husk derived silica (RHS) in hybrid natural rubber (NR) composite. Cure characteristics,mechanical and swelling properties of MS/CB and MS/RHS hybrid NR composite were investigated. As CB and RHS content increases in weight ratio of MS/CB and MS/RHS a decrease in scorch and cure time and increase in the torque, tensile, tear, modulus, hardness, crosslink density were observed, while elongation at break and swelling coefficient decreased. The aging behavior of corresponding hybrid composite materials was also evaluated at two different temperatures.
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Ahmed H. Khalil,Atef S. Abd Al-Galil,Ahmed A. Sabek,Mohamed M. Zeineldin,Seham Y. Abo-Kora 대한수의학회 2019 Journal of Veterinary Science Vol.20 No.5
This study examined the sedative, analgesic, behavioral, and clinical effects of a combination of xylazine (XY) and nalbuphine-xylazine (NA-XY) in camels. A total of five adult camels were used in a prospective randomized cross-over design with a wash out period of two weeks. Camels were allocated randomly to two treatment groups: the XY group (xylazine, 1.1mL/100 kg IV) and the NA-XY group (xylazine, 1.1mL/100 kg IV and nalbuphine, 1 mg/kg IV). The sedative, analgesic, behavioral, and clinical effects of XY and NA-XY combination were evaluated prior to administration (baseline) and at 5, 15, 30, 45, 60, 75, 90, and 120 minutes post-administration. The results showed that the NA-XY combination accelerates the onset of sedation and analgesia and prolongs the durations of both sedation (p < 0.001) and analgesia (p < 0.01). The behavioral parameters showed higher scores with a NA-XY combination than xylazine alone. Although a XY injection resulted in a significant decline in the heart and respiratory rate, the NA-XY combination group revealed a non-significant change in both clinical parameters compared to the baseline. In conclusion, the use of a NA-XY combination in camels improved the sedative and analgesic onset and duration with an improved outcome in the behavioral scores, as well as in both the heart and respiratory rates compared to XY alone.
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Khalil Ahmed M.,Msaadi Radhia,Sassi Wafa,Ghanmi Imen,Pires Rémy,Michely Laurent,Snoussi Youssef,Chevillot-Biraud Alexandre,Lau-Truong Stéphanie,Chehimi Mohamed M. 한국탄소학회 2022 Carbon Letters Vol.32 No.6
There is an ever growing interest in the development of biochar from a large variety of agrowastes. Herein, the main objective is the conversion of pomegranate peel powder biochar and its post-functionalization by phosphoric acid treatment, followed by arylation organic reaction. The latter was conducted using in situ-generated diazonium salts of 4-aminobenzoic acid (H2N-C6H4-COOH), sulfanilic acid (H2N-C6H4-SO3H) and Azure A dye. The effect of diazonium nature and concentration on the arylation process was monitored using thermal gravimetric analysis (TGA) and Raman spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). SEM pictures showed micrometer-sized biochar particles with tubular structure having about 10–20 µm-wide channels. SEM studies have shown that arylation did not affect the morphology upon arylation. The porous structure did not collapse and withstood the arylation organic reaction in acid medium did not collapse upon arylation. TGA and Raman indicated gradual changes in the arylation of biochar at initial concentrations 10–5, 10–4 and 10–3 mol L−1 of 4-aminobenzoic acid. The detailed Raman spectra peak fittings indicate that the D/G peak intensity ratio leveled off at 3.35 for 4-aminobenzoic acid initial concentration of 10–4 mol L−1, and no more change was observed, even at higher aryl group mass loading. This is in line with formation of oligoaryl grafts rather than the grafting of new aryl groups directly to the biochar surface. Interestingly, Azure A diazonium salt induced much lower extent of surface modification, likely due to steric hindrance. To the very best of our knowledge, this is the first report on diazonium modification of agrowaste-derived biochar and opens new avenues for arylated biochar and its applications.
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Ahmed Khalil,Khamis Mansour,Ahmed El Kotb,Hesham Zahra,Tareq Fahmy Abdallatif,Mohamed Salem,Marwa Shaheen 한국지질과학협의회 2023 Geosciences Journal Vol.27 No.5
An integrated geophysical survey using land magnetic and ground penetrating radar (GPR) methods was conducted to investigate the archaeological findings and ancient cultural relics at an undiscovered 100 m × 60 m in Tal-Baltus in El-Sadat city, Menofia Governorate, Egypt. The study area at Tal-Baltus was chosen among several archaeological hills in the Menofia governorate due to its archaeological significance in the Greco-Roman history of Egypt. The total area was first surveyed using the magnetic method, and then two small promising sites within this area were selected for the GPR survey. The obtained magnetic results showed the presence of remarkably high anomalies with different shapes of irregular geometry. Therefore, they are interpreted as ruins of old storage rooms related to an ancient harbor-shaped structure. Besides, numerous scattered pillars and column heads were also delineated and matched with remains of granite blocks in abundance in the study area, taking the same trend as the delineated magnetic anomalies. In addition, the GPR results highlighted several hyperbolas with variable amplitudes and sizes, which have been interpreted as the shallow foundation of a potential ancient harbor made of limestone. The comprehensive interpretation of the integrated magnetic and GPR surveys strongly suggests that the study area may be a part of an ancient harbor in addition to some other ancillary room-shaped structures used for cargo storage purposes and scattered portions of walls and pillars dating back to the Greco-Roman era.
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Crop Residues Management for Rice-Wheat Cropping System in Saline-Sodic Soil
Ahmed, Khalil,Qadir, Ghulam,Jami, Abdul-Rehman,Rafa, Hafeezullah,Mehmood, Muhammad Aamer,Han, Kyung-Hwa,Ibrahim, Muhammad Korean Society of Soil Science and Fertilizer 2014 한국토양비료학회지 Vol.47 No.4
Series of field experiments were conducted to evaluate the long term effect of gypsum and crop residue on crop yield and soil health in rice-wheat crop rotation system in salt affected soil. A saline-sodic field having $EC_e$ (electrical conductivity of the saturation extract) 4.77 ($dSm^{-1}$); pH ($H_2O$) 8.96; SAR 43.78 ($mmol\;L^{-1}$) and gypsum requirement (G.R.) 2.86 (Mg $acre^{-1}$) was selected on Soil Salinity Research Institute Farm. Five treatments consisting of ($T_1$) control, ($T_2$) gypsum at 100% G.R., ($T_3$) gypsum at 25% G.R. + wheat straw at $3Mg\;ha^{-1}$, ($T_4$) gypsum at 25% G.R. + rice straw at $3Mg\;ha^{-1}$, ($T_5$) gypsum at 25% G.R.+ rice and wheat straw at $3Mg\;ha^{-1}$ were replicated four times under completely randomized block design. The data indicated that grain and straw yield of rice and wheat was significantly (P<0.05) increased by all the amendments used either single or in combination. $T_2$ (gypsum at 100% G.R.) significantly (P<0.05) increased grain and straw yield of rice and wheat crops followed by $T_3$ (gypsum at 25% G.R. + wheat straw at $3Mg\;ha^{-1}$) when compared with control. Soil properties were also improved by used amendments, pronounced decreased in $EC_e$, $pH_s$ and SAR were recorded in $T_2$ followed by $T_3$. The efficiency of the treatments could be arranged in following order gypsum at 100% G.R.> gypsum at 25% G.R. + wheat straw at $3Mg\;ha^{-1}$ > gypsum at 25% G.R. + rice and wheat straw at $3Mg\;ha^{-1}$ > gypsum at 25% G.R. + rice straw at $3Mg\;ha^{-1}$ > control.
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