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Article: Enhancement of Structural, Optical and Photoelectrochemical Properties of n-Cu

Abdelfatah, Mahmoud / Darwesh, Nourhan / Habib, Mohamed A / Alduaij, Omar K / El-Shaer, Abdelhamid / Ismail, Walid

2023 Volume 13, Issue 7

Abstract: ... n-type ... ...

Abstract	n-type Cu
Language	English
Publishing date	2023-04-04
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2662255-5
ISSN	2079-4991
ISSN	2079-4991
DOI	10.3390/nano13071272
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: Advancement of Physical and Photoelectrochemical Properties of Nanostructured CdS Thin Films toward Optoelectronic Applications.

Ismail, Walid / Ibrahim, Ghada / Habib, Mohamed A / Alduaij, Omar K / Abdelfatah, Mahmoud / El-Shaer, Abdelhamid

Nanomaterials (Basel, Switzerland)

2023 Volume 13, Issue 11

Abstract: CdS thin films were grown on an FTO substrate at different temperatures, employing the low-cost hydrothermal method. All the fabricated CdS thin films were studied using XRD, Raman spectroscopy, SEM, PL spectroscopy, a UV-Vis spectrophotometer, ... ...

Abstract	CdS thin films were grown on an FTO substrate at different temperatures, employing the low-cost hydrothermal method. All the fabricated CdS thin films were studied using XRD, Raman spectroscopy, SEM, PL spectroscopy, a UV-Vis spectrophotometer, photocurrent, Electrochemical Impedance Spectroscopy (EIS), and Mott-Schottky measurements. According to the XRD results, all the CdS thin films were formed in a cubic (zinc blende) structure with a favorable (111) orientation at various temperatures. The Scherrer equation was used to determine the crystal size of the CdS thin films, which varied from 25 to 40 nm. The SEM results indicated that the morphology of thin films seems to be dense, uniform, and tightly attached to the substrates. PL measurements showed the typical green and red emission peaks of CdS films at 520 nm and 705 nm, and these are attributable to free-carrier recombination and sulfur vacancies or cadmium vacancies, respectively. The optical absorption edge of the thin films was positioned between 500 and 517 nm which related to the CdS band gap. For the fabricated thin films, the estimated Eg was found to be between 2.50 and 2.39 eV. According to the photocurrent measurements, the CdS thin films grown were n-type semiconductors. As indicated by EIS, resistivity to charge transfer (RCT) decreased with temperature, reaching its lowest level at 250 °C. Flat band potential and donor density were found to fluctuate with temperature, from 0.39 to 0.76 V and 4.41 × 10
Language	English
Publishing date	2023-05-30
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2662255-5
ISSN	2079-4991
ISSN	2079-4991
DOI	10.3390/nano13111764
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Article: Effects of adiabatic flame temperature on flames’ characteristics in a gas-turbine combustor

Aliyu, Mansur / Abdelhafez, Ahmed / Nemitallah, Medhat A. / Said, Syed A.M. / Habib, Mohamed A.

Energy. 2022 Mar. 15, v. 243

2022

Abstract: In this study a comparison between the premixed methane oxygen-enriched-air (CH₄/O₂/N₂) and oxy-methane (CH₄/O₂/CO₂) in a gas-turbine model combustor that imitates pre-mixers in operational air-fuel dry low emissions gas turbines is presented. The ... ...

Abstract	In this study a comparison between the premixed methane oxygen-enriched-air (CH₄/O₂/N₂) and oxy-methane (CH₄/O₂/CO₂) in a gas-turbine model combustor that imitates pre-mixers in operational air-fuel dry low emissions gas turbines is presented. The comparison and analyses that follow in this study are based on the results of experiments conducted. The combustion stability maps were obtained through the estimation of acoustic limits and measurement of blowout limits within the space of equivalence ratio (φ) – oxygen fraction (OF). The stability maps obtained were superimposed on the contour plots of constant adiabatic temperature (Tₐd), Reynolds number (Re), and power density (PD) of the combustor. Effects of Tₐd on flame macrostructure, flame stability, flame speed, and blowout mechanism were investigated. The temperature distributions were also measured. The study results indicated that blowout of CO₂ as well as N₂ flames occur at constant Tₐd. These results are more pronounced in the case of the multi-hole burner because, such burner is not characterized with sporadic nature of flame lifting and reattachment that dominate the occurrence of a blowout in swirl burner; for a given OF, φ at which CO₂ flames blowout is higher than that of N₂ flames due to the poorer resistance of oxy-flames to blowout as compared to air flames; the stable combustion zone of CO₂ flames is larger than that of N₂ flames.
Keywords	Reynolds number ; acoustics ; carbon dioxide ; combustion ; energy ; methane ; oxygen ; temperature
Language	English
Dates of publication	2022-0315
Publishing place	Elsevier Ltd
Document type	Article
ZDB-ID	2019804-8
ISSN	0360-5442 ; 0360-5442
ISSN (online)	0360-5442
ISSN	0360-5442
DOI	10.1016/j.energy.2021.123077
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Article: Second law analysis of premixed and non-premixed oxy-fuel combustion cycles utilizing oxygen separation membranes

Habib, Mohamed A / Imteyaz, Binash / Nemitallah, Medhat A

Applied energy. 2020 Feb. 01, v. 259

2020

Abstract: Two basic oxy-combustion cycles were investigated under premixed and non-premixed combustion conditions and the results were compared in terms of exergy destruction and first and second law efficiencies. An air separation unit (ASU) was used for oxygen ... ...

Abstract	Two basic oxy-combustion cycles were investigated under premixed and non-premixed combustion conditions and the results were compared in terms of exergy destruction and first and second law efficiencies. An air separation unit (ASU) was used for oxygen separation from the feeding air in the premixed combustion cycle. In the non-premixed combustion cycle, CO2/H2O splitting membrane reactors were utilized, where oxygen separation and in situ oxy-combustion processes occur within the reactor. A gas turbine cycle, working on conventional air combustion of methane, was selected as the reference base case. Commercial process simulator Aspen Hysys V7.3 was used to model and simulate the different systems. The work proposed novel cycle designs for higher cycle efficiency under oxy-combustion conditions. Cycle performance using ion transport membrane (ITM) and ASU was evaluated and compared. Losses in the ASU and the condenser were identified to be the main reason for lower efficiencies and, hence, the systems were modified to include heat recuperation cycles. Additional two modified oxy-combustion cycle designs were proposed. First law and second law efficiencies of the modified premixed cycle were found to be 34.1% and 47%, compared to 35.1% and 44% for the reference air-combustion cycle. The overall thermal and second law efficiencies of the modified non-premixed cycle were the highest among all cycles with 37.8% and 50.4% efficiencies. The effects of hydrogen addition on the efficiencies of the premixed system were evaluated. It was found that hydrogen addition results in increased first and second law efficiencies of the cycle; however, the increase is only marginal.
Keywords	air ; carbon dioxide ; combustion ; exergy ; heat ; hydrogen ; methane ; models ; oxygen
Language	English
Dates of publication	2020-0201
Publishing place	Elsevier Ltd
Document type	Article
ZDB-ID	2000772-3
ISSN	0306-2619
ISSN	0306-2619
DOI	10.1016/j.apenergy.2019.114213
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Analysis of Highly CO

Habib, Mohamed A / Haque, Md Azazul / Nemitallah, Medhat A / Abdelhafez, Ahmed / Khalifa, Atia E

ACS omega

2022 Volume 7, Issue 45, Page(s) 41493–41507

Abstract: Premixed oxy-propane flames are investigated numerically in a multihole model gas turbine combustor at various inlet mixture compositions over a range of equivalence ratios (Ø: 0.241-0.500), oxygen fractions (OF: 32.4-60.0%), and adiabatic flame ... ...

Abstract	Premixed oxy-propane flames are investigated numerically in a multihole model gas turbine combustor at various inlet mixture compositions over a range of equivalence ratios (Ø: 0.241-0.500), oxygen fractions (OF: 32.4-60.0%), and adiabatic flame temperatures (
Language	English
Publishing date	2022-11-03
Publishing country	United States
Document type	Journal Article
ISSN	2470-1343
ISSN (online)	2470-1343
DOI	10.1021/acsomega.2c05274
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Artificial intelligence for control and optimization of boilers’ performance and emissions: A review

Nemitallah, Medhat A. / Nabhan, Mohammad A. / Alowaifeer, Maad / Haeruman, Agus / Alzahrani, Fahad / Habib, Mohamed A. / Elshafei, Moustafa / Abouheaf, Mohammed I. / Aliyu, Mansur / Alfarraj, Motaz

Journal of Cleaner Production. 2023 Sept., v. 417 p.138109-

2023

Abstract: Burning fossil fuels is a major concern for global warming control. In Saudi Arabia, steam power plants that relay on boilers to produce the steam accounted for around 50% of the total electricity generation capacity in 2021, in addition to 15% capacity ... ...

Abstract	Burning fossil fuels is a major concern for global warming control. In Saudi Arabia, steam power plants that relay on boilers to produce the steam accounted for around 50% of the total electricity generation capacity in 2021, in addition to 15% capacity from co-generation power plants. Fossil-based energy production produces harmful emissions, mostly NOx. The case of combustion efficiency and NOx emissions is complicated and cannot be addressed by simple theoretical model. This paper investigates the existing literature exploring data driven approaches via Artificial Intelligence (AI) and machine learning (ML) in a variety of applications, including mainly boiler optimization for efficient and clean energy production. The study discusses the importance of energy intelligence for industries in supporting decision making and prediction considering supervised learning, unsupervised learning, semi-supervised learning, and reinforcement learning. Expert systems, artificial neural networks (ANN), genetic algorithms (GA), fuzzy logic (FL), and different hybrid systems, which incorporate two or more techniques, are all included in AI systems. A condensed review of some recent literature is presented on the applications of support vector machines, ANN, GA, FL, and hybrid systems to combustion systems for emphasizing boilers' performance and emissions. An overview of boiler dynamics and control are presented and the use of AI for trade-off between boiler's efficiency and NOx emissions is discussed, with special focus being made on hydrogen combustion. The reported findings in this study demonstrate the promise of AI in control of emissions and optimization of performance in boilers with the least amount of construction and operating expenditures. The complexity and a number of restrictions present in emissions control systems, however, may reduce the likelihood of success. The specific perspectives are found to be data availability, data reliability, validity of methodology, and system complexity. It is concluded that wide variety of AI approaches have been used in a diversity of disciplines for modelling, predicting performance and controlling emissions of combustion processes. It is indicated that data representing the history and performance of real systems along with the proper selection of the AI model are crucial for setting up such systems. Based on this study, it can be stated that AI models are great tools towards better performance of boilers at minimum emissions.
Keywords	clean energy ; combustion ; combustion efficiency ; electricity generation ; fuzzy logic ; hydrogen ; prediction ; steam ; theoretical models ; Saudi Arabia ; Artificial intelligence ; Boilers dynamics and control ; Combustion systems ; Energy intelligence ; Boilers ; NOx emissions
Language	English
Dates of publication	2023-09
Publishing place	Elsevier Ltd
Document type	Article ; Online
ISSN	0959-6526
DOI	10.1016/j.jclepro.2023.138109
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Azo-Linked Porous Organic Polymers for Selective Carbon Dioxide Capture and Metal Ion Removal.

Abdelnaby, Mahmoud M / Saleh, Tawfik A / Zeama, Mostafa / Abdalla, Mahmoud Atef / Ahmed, Hossam M / Habib, Mohamed A

ACS omega

2022 Volume 7, Issue 17, Page(s) 14535–14543

Abstract: The facile and environmentally friendly synthesis of porous organic polymers with designed polar functionalities decorating the interior frameworks as an excellent adsorbent for selective carbon dioxide capture and metal ion removal is a target worth ... ...

Abstract	The facile and environmentally friendly synthesis of porous organic polymers with designed polar functionalities decorating the interior frameworks as an excellent adsorbent for selective carbon dioxide capture and metal ion removal is a target worth pursuing for environmental applications. In this regard, two azo-linked porous organic polymers denoted man-Azo-P1 and man-Azo-P2 were synthesized in water by the azo-linking of 4,4'-diaminobiphenyl (benzidine) and 4,4'-methylenedianiline, respectively, with 1,3,5-trihydroxybenzene. The resulting polymers showed good BET surface areas of 290 and 78 m
Language	English
Publishing date	2022-04-21
Publishing country	United States
Document type	Journal Article
ISSN	2470-1343
ISSN (online)	2470-1343
DOI	10.1021/acsomega.1c05905
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Article: Review of Fuel/Oxidizer-Flexible Combustion in Gas Turbines

Haque, Md. Azazul / Nemitallah, Medhat A / Abdelhafez, Ahmed / Mansir, Ibrahim B / Habib, Mohamed A

Energy & fuels. 2020 July 30, v. 34, no. 9

2020

Abstract: Strict emission control regulations call for continuous advancement in existing combustion and carbon-capture technologies to mitigate the rise in pollutants and greenhouse gases from fossil fuel combustion. Concurrently, improvements in combustion ... ...

Abstract	Strict emission control regulations call for continuous advancement in existing combustion and carbon-capture technologies to mitigate the rise in pollutants and greenhouse gases from fossil fuel combustion. Concurrently, improvements in combustion systems would also yield lower fuel consumption and operational cost with greater efficiency. This review addresses these concerns and presents the overview of different combustion technologies and burner designs for cleaner power generation in gas turbines. Emission characteristics are discussed and compared for different combustion concepts, including lean premixed air combustion and oxy-combustion. Various gas turbine burner technologies, including dry low NOₓ, enhanced-vortex, perforated-plate, and micromixer burners, are discussed extensively, in terms of their operating principle, fuel flexibility, and potential for superior performance under oxy-combustion conditions. Enhanced-vortex and micromixer burners show remarkable flame stability and fuel flexibility and are thus recommended for implementation with hydrogen enrichment in future oxy-fuel gas turbines. The fuel-flexibility approaches for clean energy production, such as hydrogen combustion, hydrogen-enriched combustion, syngas combustion, ammonia combustion, and fuel blending, are explored as well. With the vast recent advances in the techniques of hydrogen production and storage, hydrogen-fueled gas turbines seem to be the perfect choice for clean energy production. The adiabatic flame temperature is identified as a key controlling parameter for the design of oxidizer-flexible combustors in clean gas turbines.
Keywords	air ; ammonia ; clean energy ; energy ; energy use and consumption ; fossil fuels ; fuel combustion ; greenhouses ; hydrogen ; hydrogen production ; operating costs ; power generation ; synthesis gas ; temperature
Language	English
Dates of publication	2020-0730
Size	p. 10459-10485.
Publishing place	American Chemical Society
Document type	Article
Note	NAL-AP-2-clean
ZDB-ID	1483539-3
ISSN	1520-5029 ; 0887-0624
ISSN (online)	1520-5029
ISSN	0887-0624
DOI	10.1021/acs.energyfuels.0c02097
Database	NAL-Catalogue (AGRICOLA)

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Article: Comparative analysis of the stability and structure of premixed C3H8/O2/CO2 and C3H8/O2/N2 flames for clean flexible energy production

Ali, Asif / Nemitallah, Medhat A / Abdelhafez, Ahmed / Hussain, Muzafar / Kamal, M. Mustafa / Habib, Mohamed A

Energy. 2021 Jan. 01, v. 214

2021

Abstract: The study compares the macrostructure and stabilization parameters of premixed oxy-propane (C₃H₈/O₂/CO₂) and oxygen-enriched air-propane (C₃H₈/O₂/N₂) flames at fixed inlet velocity of 5.2 m/s and under similar conditions of oxygen fraction (OF= 21%–70%) ... ...

Abstract	The study compares the macrostructure and stabilization parameters of premixed oxy-propane (C₃H₈/O₂/CO₂) and oxygen-enriched air-propane (C₃H₈/O₂/N₂) flames at fixed inlet velocity of 5.2 m/s and under similar conditions of oxygen fraction (OF= 21%–70%) and equivalence ratio (ϕ=0.1−1.0) in a model dry-low-emissions (DLE) gas turbine combustor. The combustor stability maps were plotted within the ϕ-OF domain against background contours of constant adiabatic flame temperature (AFT), to quantify the blowout and flashback limits. It was found for both CO₂- and N₂-diluted flames that the blowout and flashback limits followed constant AFT contours on the stability maps. The blowout limit of both types of flames roughly followed the same AFT contour of about ∼1580 K, while the flashback limits followed the constant AFT contour of 2350 K. This implies that C₃H₈/O₂/N₂ flames blow out at leaner conditions compared to C₃H₈/O₂/CO₂ flames. The effect of diluent type on blowout limit diminishes at higher OF; above 55% both flames blow out at ϕ∼0.2. All flames of the same AFT exhibited considerably identical shapes despite having different OF and ϕ. Based on that, the design and operation of future oxy-fuel turbines is recommended to be AFT-based rather than OF or ϕ.
Keywords	energy ; oxygen ; temperature
Language	English
Dates of publication	2021-0101
Publishing place	Elsevier Ltd
Document type	Article
Note	NAL-AP-2-clean
ZDB-ID	2019804-8
ISSN	0360-5442 ; 0360-5442
ISSN (online)	0360-5442
ISSN	0360-5442
DOI	10.1016/j.energy.2020.118887
Database	NAL-Catalogue (AGRICOLA)

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Article: The Characteristics of Oxycombustion of Liquid Fuel in a Typical Water-Tube Boiler

Imteyaz, Binash / Habib Mohamed A / Ben-Mansour Rached

Energy & Fuels. 2017 June 15, v. 31, no. 6

2017

Abstract: Among the various carbon capture technologies, oxyfuel combustion provides an effective way to reduce COâ emissions, because of similar flame characteristics, relative to those of air combustion, and its ability to be retrofitted in the existing plants. ...

Abstract	Among the various carbon capture technologies, oxyfuel combustion provides an effective way to reduce COâ emissions, because of similar flame characteristics, relative to those of air combustion, and its ability to be retrofitted in the existing plants. In this work, combustion of liquid fuel in Oâ/COâ environment inside a water-tube boiler has been modeled numerically, and the results were compared with that of the air combustion case. Two cases of oxycombustion were studied: (i) OF21 (21% oxygen (by volume) and 79% COâ (by volume)) and (ii) OF29 (29% oxygen (by volume) and 71% COâ (by volume)). The model was extended to study the effects of droplet size and swirl number on the combustion characteristics of the liquid fuel. Probability density function (PDF) was applied to solve the turbulenceâchemistry interaction. It was found that the replacement of Nâ from air with carbon dioxide significantly reduces the temperature level. It was also found that reducing the COâ concentration results in an increase in the flame temperature. For the air combustion case, heat transfer to the water jackets was much higher than that of oxycombustion cases.
Keywords	air ; boilers ; carbon ; carbon dioxide ; combustion ; droplet size ; fuels ; greenhouse gas emissions ; heat transfer ; models ; nitrogen ; oxygen ; probability distribution ; temperature
Language	English
Dates of publication	2017-0615
Size	p. 6305-6313.
Publishing place	American Chemical Society
Document type	Article
ZDB-ID	1483539-3
ISSN	1520-5029 ; 0887-0624
ISSN (online)	1520-5029
ISSN	0887-0624
DOI	10.1021%2Facs.energyfuels.7b00489
Database	NAL-Catalogue (AGRICOLA)

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