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- 저자 : Muhammad Ramzan Abdul Karim (검색결과 4 건)
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Abdul Karim Muhammad Ramzan,Khan Muhammad Awais,Zaman Atteeq Uz,Hussain Azhar 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.1
Hexagonal boron nitride (h-BN)-based composites have been gaining prominence due to their versatile and significantly improved properties. For example they have good strength, better thermal conductivity, excellent resistance to thermal shocks and high temperatures, molten metal erosion resistance, ablation resistance, excellent machinability, good lubricating and chemical inertness. Owing to its excellent comprehensive properties, h-BN has significant potential applications in the fields of electronics, machinery, aerospace, nuclear energy, and metallurgy. Current article, first tries to critically review the literature, mainly published in the last decade, exploring the peculiar crystal structure and enhanced properties of h-BN and then various h-BN-based ceramics and its composites with oxides, nitrides, carbides, metals, and complex ceramics have been discussed based on their fabrication methods, mechanical properties, and the resultant applications. As per the reviewed results, hot pressing results in enhanced mechanical properties such as fracture toughness and flexural strength owing to the incorporation of BN by in situ reaction, which prevents BN agglomeration and reduces the size and quantity of defects. In contrast, the pressureless sintering method is reported to cause poor mechanical properties as compared to other fabrication methods of h-BN ceramics due to large porosity and poor bonding between h-BN grains caused by the forming of card room structure. Consequently, the green body's shrinkage is obstructed, and the expansion is occurred during the sintering process. All these aspects have been discussed in detail and they are the part of this review article.
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Wajahat Khalid,Muhammad Ramzan Abdul Karim,Mohsin Ali Marwat The Korean Electrochemical Society 2024 Journal of electrochemical science and technology Vol.15 No.1
The text highlights the growing need for eco-friendly energy storage and the potential of metal-organic frameworks (MOFs) to address this demand. Despite their promise, challenges in MOF-based energy storage include stability, reproducible synthesis, cost-effectiveness, and scalability. Recent progress in supercapacitor materials, particularly over the last decade, has aimed to overcome these challenges. The review focuses on the morphological characteristics and synthesis methods of MOFs used in supercapacitors to achieve improved electrochemical performance. Various types of MOFs, including monometallic, binary, and tri-metallic compositions, as well as derivatives like hybrid nanostructures, sulfides, phosphides, and carbon composites, are explored for their energy storage potential. The review emphasizes the quest for superior electrochemical performance and stability with MOF-based materials. By analyzing recent research, the review underscores the potential of MOF-based supercapacitors to meet the increasing demands for high power and energy density solutions in the field of energy storage.
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Raza, Syed Abbas,Karim, Muhammad Ramzan Abdul,Shehbaz, Tauheed,Taimoor, Aqeel Ahmad,Ali, Rashid,Khan, Muhammad Imran The Korean Electrochemical Society 2022 Journal of electrochemical science and technology Vol.13 No.2
In the present study, the corrosion behavior of aluminum Al-7075 tempered (T-6 condition) alloy was evaluated by immersion testing and electrochemical testing in 1.75% and 3.5% NaCl environment at acidic, neutral and basic pH. The data obtained by both immersion tests and electrochemical corrosion tests (potentiodynamic polarization and electrochemical impedance spectroscopy tests) present that the corrosion rate of the alloy specimens is minimum for the pH=7 condition of the solution due to the formation of dense and well adherent thin protective oxide layer. Whereas the solutions with acidic and alkaline pH cause shift in the corrosion behavior of aluminum alloy to more active domains aggravated by the constant flux of acidic and alkaline ions (Cl<sup>-</sup> and OH<sup>-</sup>) in the media which anodically dissolve the Al matrix in comparison to precipitated intermetallic phases (cathodic in nature) formed due to T6 treatment. Consequently, the pitting behavior of the alloy, as observed by cyclic polarization tests, shifts to more active regions when pH of the solutions changes from neutral to alkaline environment due to localized dissolution of the matrix in alkaline environment that ingress by diffusion through the pores in the oxide film. Microscopic analysis also strengthens the results obtained by immersion corrosion testing and electrochemical corrosion testing as the study examines the corrosion behavior of this alloy under a systematic evaluation in marine environment.
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Riaz Iqra,Qamar Obaid Ali,Jamil Farrukh,Hussain Murid,Inayat Abrar,Rocha-Meneses Lisandra,Akhter Parveen,Musaddiq Sara,Karim Muhammad Ramzan Abdul,박영권 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.11
The use of biodiesel is a proactive measure that can be implemented to reduce emissions of greenhouse gases and other adverse environmental impacts. However, one of the major setbacks to biodiesel production is its relatively higher cost compared to petroleum diesel. The optimistic solution to this is valorization of biomasses like waste chicken fat (WCF) and clay for deriving non-edible oil and catalyst respectively. Herein, we report the synthesis of clay derived SiO2 catalyst impregnated with SrO, Bi2O3, CuO and CaO. The developed catalysts were characterized by FTIR, XRD, and SEM. XRD studies confirmed the successful impregnation of active metallic oxide on SiO2 support. Further, these catalysts were employed for biodiesel production from WCF, and SrO/SiO2 was found to be most effective and efficient catalyst for biodiesel production from WCF. Hence, SrO/SiO2 was adapted to optimize the different transesterification reaction parameters such as methanol to oil ratio, catalyst loading, reaction temperature and time. The optimized conditions for maximum biodiesel yield 98.9% were found to be 65 °C in 1 h with 12:1 methanol to oil ratio and 1 wt% catalyst loading. The biodiesel produced was also analyzed by GC-MS. The obtained biodiesel yield shows that clay can be a potential, and cost-effective, catalyst source to produce biodiesel from WCF.
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