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Article Citation - WoS: 15Citation - Scopus: 17Pei Modifiednatural Sands of Florida as Catalysts for Hydrogen Production From Sodium Borohydride Dehydrogenation in Methanol(Wiley-hindawi, 2021) Inger, Erk; Demirci, Sahin; Can, Mehmet; Sunol, Aydin K.; Philippidis, George; Sahiner, NurettinSand samples from Tampa (T) and Panama (P) City beaches in Florida were used as catalysts for dehydrogenation of NaBH4 in methanol. T and P sand samples were sieved to <250, 250 to 500, and >500 mu m sizes, and the smallest fractions resulted in faster hydrogen generation rates (HGR), 565 +/- 18 and 482 +/- 24 mL H-2 (min.g of catalyst)(-1), respectively. After various base/acid treatments, HGR values of 705 +/- 51 and 690 +/- 47 mL H-2 (min g of catalyst)(-1) for HCl-treated T and P sand samples were attained, respectively. Next, T and P sand samples were modified with polyethyleneimine (PEI) that doubled the HGR values, 1344 +/- 103, and 1190 +/- 87 mL H-2 (min.g of catalyst)(-1) and increased similar to 8-fold, 4408 +/- 187, and 3879 +/- 169 mL H-2 (min g of catalyst)(-1), correspondingly after protonation (PEI+). The Ea values of T and P sand samples were calculated as 24.6 and 25.9 kJ/mol, and increased to 36.1, and 36.6 kJ/mol for T-PEI(+)and P-PEI(+)samples, respectively.Article Citation - WoS: 27Citation - Scopus: 29Catalytic activity of metal-free amine-modified dextran microgels in hydrogen release through methanolysis of NaBH4(Wiley, 2020) Inger, Erk; Sunol, Aydin K.; Sahiner, NurettinPolymeric microgels were prepared from dextran (Dex) by crosslinking linear natural polymer dextran with divinyl sulfone (DVS) with a surfactant-free emulsion technique resulting in high gravimetric yield of 78.5 +/- 5.3% with wide size distribution. Dex microgels were chemically modified, and then used as catalyst in the methanolysis of NaBH4 to produce H-2. The chemical modification of Dex microgel was done on epichlorohydrin (ECH)-reacted Dex microgels with ethylenediamine (EDA), diethylenetriamine (DETA), and triethylenetetraamine (TETA) in dimethylformamide (DMF) at 90 degrees C for 12 hours. The modified dextran-TETA microgels were protonated using treatment with hydrochloric acid (HCl) and m-Dex microgels-TETA-HCl was found to be a very efficient catalyst for methanolysis of NaBH4 to produce H-2. The effects of reaction temperature and NaBH4 concentration on H-2 generation rates were investigated and m-Dex microgels-TETA-HCl catalyst possessed excellent catalytic performances with 100% conversion and 80% activity at end of 10 consecutive uses and was highly re-generatable with simple HCl treatment. Interestingly, m-Dex microgels-TETA-HCl catalyst can catalyze NaBH4 methanolysis reaction in a mild temperature range 0 to 35 degrees C with Ea value of 30.72 kJ/mol and in subzero temperature range, -20 to 0 degrees C with Ea value of 32.87 kJ/mol, which is comparable with many catalysts reported in the literature.Article Citation - WoS: 1Citation - Scopus: 1Mass Driver Design Traveling Earth to the Moon(Ieee-inst Electrical Electronics Engineers inc, 2019) Inger, Erk; Inger, ErkIn this article, the flight of a mass driver was designed for launch from the Earth with Electro Magnetic Space Launching System (EMSLS). Then the orbit exit from the Earth at 185 km and orbit entry the Moon at 100kmwere examined with respect to change of trajectories by using chemical fuel and the engine in the mass driver. Electromagnetically launched mass drivers should orbit with a specified orbital velocity at a designated altitude. In this paper, the energy is transferred externally to a mass driver throughout the flight path the electromagnetic coil system called multistage (EMSLS) designated in order to achieve the specified orbital velocity. The mass driver is synchronously accelerated by a voltage through the capacitors which are used for storing energy. This energy is transferred through a switching inductor to the circuit of the mass driver so that the mass driver is launched into the orbit with a muzzle velocity. However, this fact creates high air drag energy losses due to atmospheric conditions and high velocity obtained in EMSLS. Thus, in the mass driver at 21km altitude an engine starts to increase the velocity of the system to reach orbital velocity. The final aim of this article is to capture the transfer of $\Delta \text{v}$ cost for traveling to the Moon. At any given arrival time in order to guide the system, designers only consider the gravity of the Earth and gravity of the Moon by using a Direct Lunar Transfer Trajectory for the Earth to the Moon approach. Finally, EMSLS was evaluated as a more advantageous and complimentary alternative to chemical propulsion systems for space transportation.
