A. F. Alshater

Bio: A. F. Alshater is an academic researcher from University of Bahrain. The author has contributed to research in topics: Pitting corrosion & Corrosion. The author has an hindex of 6, co-authored 11 publications receiving 82 citations.

Recent Advances in Enzymatic Conversion of Microalgal Lipids into Biodiesel

Abstract: The use of microalgae to produce biodiesel is a beneficial and green substitute for conventional fossil fuels (a major source of greenhouse gas emissions). Microalgae have several merits, including...

Characterization of the stress corrosion cracking behavior of thermally sensitized 20Cr-25Ni stainless steel in a simulated cooling pond environment

Abstract: Niobium stabilized 20Cr-25Ni stainless steel is used for nuclear fuel cladding in the UK's fleet of advanced gas cooled reactors (AGRs). The cladding can have chromium-depleted grain boundaries as a consequence of irradiation in a reactor core, rendering a small proportion of cladding susceptible to intergranular stress corrosion cracking in cooling pond waters after removal from the reactor. In this work, thermal sensitization was used to simulate chromium depletion and the sensitized material was assessed for its susceptibility to pitting corrosion and stress corrosion cracking using slow strain rate testing (SSRT). Elevated chloride concentrations were used to accelerate corrosion initiation and propagation. In 10 ppm chloride and 80 °C, the pitting potential was at potentials between +375 mV and +400 mV (SCE). SSRT appeared to lower the pitting potential, with intergranular corrosion and intergranular stress corrosion cracks observed to nucleate at potentials of +200 mV (SCE).

Effects of Cinnamaldehyde as an Eco-Friendly Corrosion Inhibitor on Mild Steel in Aerated NaCl Solutions

Abstract: This article investigates the impact of cinnamaldehyde as an eco-friendly inhibitor in mitigating corrosion detriment on mild steel in aerated NaCl (3% w/w) using weight loss and potentiodynamic polarization methods. The results indicate moderate inhibition efficiency of cinnamaldehyde reaching around 70% at an optimum level of 0.5 g/L or 500 ppm by establishing an adsorption film on metal surface. Adsorption of the cinnamaldehyde seemed to adhere to the Langmuir isotherm. The corrosion rate decreased with cinnamaldehyde dose up to the optimum level while increased slowly with the medium temperature. The activation energy (Ea) achieved with cinnamaldehyde was found to be lower than that of without cinnamaldehyde. The polarization curves revealed that the inhibitor performs as a mixed-type inhibitor since it diminishes both anodic and cathodic current densities. The calculated inhibition efficiencies using both corrosion monitoring techniques were found to be in good agreement. Additionally, the mild steel surfaces (inhibited and uninhibited) were examined by using SEM–EDX analysis.

Effect of Surface Finish on the Pitting Corrosion Behavior of Sensitized AISI 304 Austenitic Stainless Steel Alloys in 3.5% NaCl Solutions

Abstract: The effect of surface condition down to 120 and 1000-grit finish, corresponding to 1.47 and 0.06 microns RMS (Root Mean Square), respectively, on the pitting corrosion behavior of sensitized and mill-annealed AISI (American iron and steel institute) 304 stainless steel was studied in 3.5% NaCl solutions at 23 and 50°C by electrochemical methods. The polarization curves have revealed a clear dependence of pitting corrosion on the surface finish, on the degree of sensitization, as well as on the test temperature. Surface condition has made a significant contribution to pit initiation in that the pitting potential was lowered as the surface roughness increased. The deleterious effect of surface roughness on the pitting potential of the AISI 304 stainless steel alloy in 3.5% NaCl is more pronounced on sensitized samples and becomes more evident with increasing sensitization time and test temperature.

American Society of Mechanical Engineers (ASME)

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Biodiesel production from microalgae using lipase-based catalysts: Current challenges and prospects

Abstract: The excessive demand for fossil fuels has caused severe environmental impacts, such as GHG-related effects and widespread pollution. Firstly, it is essential to identify the main problems arising from fossil fuel production and consumption, which will enable the search and implementation of technological, sustainable, and economical alternatives to mitigate the current issue. With the modern technological advances in this specific area, the use of biofuels has expanded, given their high potential of production from diverse classes of biomass. Producing biodiesel from microalgae oil specifically, as a way of obtaining clean and renewable energy, can play a significant role in this context, and the process is of high interest to the energy sector. Biodiesels are produced through mixtures of ethyl esters or fatty acid methyl esters, which are generated by the synthesis of oil with alcohol in the presence of the enzyme alcohol lipase. There are clear challenges linked to the new technologies employed to obtain biofuels from microalgae, and there also are strong prospects to these approaches, since they are very energy-efficient and environmentally friendly. Thus being, the present review describes the main aspects associated with biodiesel production from microalgae, highlighting the fundamentals of the technique, the immobilization processes followed, the use of solvents to optimize reaction media, bioreactor systems, as well as the performance optimization of microalgae biodiesel-based engines, while considering important economic and environmental aspects. Future trends in the biofuel scientific research and industry are also included, aiming at fostering discussions on the development of other significant advances in the use of microalgae lipase and oil technology for biodiesel production.

How to Build a Microplastics‐Free Environment: Strategies for Microplastics Degradation and Plastics Recycling

Abstract: Microplastics are an emergent yet critical issue for the environment because of high degradation resistance and bioaccumulation. Unfortunately, the current technologies to remove, recycle, or degrade microplastics are insufficient for complete elimination. In addition, the fragmentation and degradation of mismanaged plastic wastes in environment have recently been identified as a significant source of microplastics. Thus, the developments of effective microplastics removal methods, as well as, plastics recycling strategies are crucial to build a microplastics‐free environment. Herein, this review comprehensively summarizes the current technologies for eliminating microplastics from the environment and highlights two key aspects to achieve this goal: 1) Catalytic degradation of microplastics into environmentally friendly organics (carbon dioxide and water); 2) catalytic recycling and upcycling plastic wastes into monomers, fuels, and valorized chemicals. The mechanisms, catalysts, feasibility, and challenges of these methods are also discussed. Novel catalytic methods such as, photocatalysis, advanced oxidation process, and biotechnology are promising and eco‐friendly candidates to transform microplastics and plastic wastes into environmentally benign and valuable products. In the future, more effort is encouraged to develop eco‐friendly methods for the catalytic conversion of plastics into valuable products with high efficiency, high product selectivity, and low cost under mild conditions.