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Article Citation - WoS: 7Citation - Scopus: 8Can Fool's Gold "pyrite" Become Real Gold as a Catalyst for Clean-Energy H2 Production?(Pergamon-elsevier Science Ltd, 2019) Inger, Erk; Inger, ErkThe natural, most abundant sulfide mineral of pyrite was modified using polyethyleneimine (PEI) for use as a catalyst in H-2 release reactions from NaBH4 in methanol. The catalytic performances of pyrite, pyrite-PEI, and protonated pyrite-PEI (pyrite-PEI+) were compared and the hydrogen generation rate (HGR) values of 795 +/- 26, 2883 +/- 190, and 4320 +/- 188 mL H-2/(g of catalyst x min)(-1) were measured for H-2 production from NaBH4 methanolysis. The effect of methanol:water mixture at various ratios, the amount of catalyst, the concentration of NaBH4, and temperature on H-2 production from NaBH4 in methanol catalyzed by pyrite-PEr were investigated. The activation energies for pyrite-PEI, and pyrite-PEI+ catalyzed H-2 release reactions were calculated as 47.2 and 36.8 kJ/mol, respectively. It was found that the activity % for the pyrite-PEI+ catalyst decreased to 76.2 +/- 2.7% after five consecutive uses with 100% conversion for each re-use study. Furthermore, the re-generation of pyrite-PEI+ catalyst after the 5th usage was readily ensured by HCl treatment to completely recover and further increase the activity% of the catalyst. Therefore, pyrite was shown to be a useful re-generable and economic green catalyst for H-2 production in many potential applications. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Article Citation - WoS: 10Citation - Scopus: 13Electromagnetic Launching Systems To Geosynchronously Equatorial Orbit in Space and Cost Calculations(Ieee-inst Electrical Electronics Engineers inc, 2017) Inger, Erk; Inger, ErkElectromagnetic launching mass driver system (projectile) has been examined and evaluated as an eligible alternative to the chemical propulsion systems, in space transportation. The projectile has been arranged to reach to its orbital speed at delivered altitude, with an energy transferred externally to a projectile all the flyway through the electromagnetic launcher. The multistage electromagnetic launcher structure contains the capacitors for storing energy and transfers this energy through a switching inductor to a mass driver. The mass driver is synchronously being energized by a voltage through an oscillating coil-capacitor circuit. This paper presents dependence and optimization of design and performance parameters of coilgun equations. Cost estimations of electromagnetic launching system are also calculated in energy per unit mass.Article Citation - WoS: 51Citation - Scopus: 52Porous Carbon Particles as Metal-Free Superior Catalyst for Hydrogen Release From Methanolysis of Sodium Borohydride(Pergamon-elsevier Science Ltd, 2020) Demirci, Sahin; Yildiz, Mustafa; Inger, Erk; Sahiner, NurettinCarbon materials can be readily prepared from wood derivatives, monosaccharaides such as pentose/hexose and/or polysaccharides in addition to many starting materials by treatment of thermal, chemical and hydrothermal methods. Here, the porous carbon (PC) particles were prepared by removal of silica particles from previously prepared carbon-silica composites by hydrothermal and carbonization process from sucrose. Then, PC particles were modified with polyethyleneimine (PEI) to prepared amine functionalized PC-PEI particles and protonated with hydrochloric acid, PC-PEI+. Finally, these prepared carbon-based particles were used as catalyst for H-2 release from NaBH4 methanolysis and PC-PEI+ was found as the most effective catalyst at 25 degrees C with 4040 +/- 126 mL H-2. min(-1).g(-1) HGR value. The E s value of 23.9 kJ/mol in H-2 release reaction from NaBH4 methanolysis catalyzed by PC-PEI+ that is comparable and/or better than most of studies reported in literature. The activity% of PC-PEI+ catalyst was 72% after fifth consequential runs. Additionally, the regeneration ability of PC-PEI+ catalyst was also shown that after fifth regeneration process, there is only 5% decrease in activity%. (C) 2019 Elsevier Ltd. All rights reserved.
