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Article Launching To an Orbit With a Chemical Propellant Staged Rocket Systems(2022) Inger, Erk; Inger, ErkThere is one way to explore space by using the space launch vehicles, which is known as rockets, and it can carry useful load named simply as payload of satelite from Earth into Space. In this study, performance predictions of the multi rocket motors are discussed and compared with single rocket motor with the same amount of propellant used for space travel. In this article in serial or tandem staging schemes, the boosting stage is usually the largest, the second stage and subsequent upper stages are above it, usually decreasing in size are used. In boosting stage parallel staging schemes solid or liquid rocket boosters are used to assist with launch. At low level starting to high altitude higher density fuel solid fuels, kerogen and cryogenic hydrogen(-250°C) are used as fuel. In solid propellants oxidizer is generally ammonium per chloride is used but in cryogenic liquid propellants oxygen(183.3°C) are used. In the first stage, both liquid propellant in a booster and five solid rocket propellent are used to reach about a certain altitude and velocity. In second stage, after reducing the weight by ejecting the five solid rocket propellent and only liquid propellant is used only to reach the an extra altitudes and velocities at low earth orbit (LEO). Drag and gravity effects are successfully used in all of the calculations. The added total result of velocities and altidudes found by these staged rockets are higher than the first single staged case. The advantage of multistage rockets, having same amount of propellant in staged rockets where total velocity will be increased by separating and removing waste from the system weight out of the system. Use of staged rocket system are usefull for increasing the amount of payload and decreasing the cost per unit weight as well.Article Boric Acid Versus Boron Trioxide as Catalysts for Green Energy Source H2 Production From Sodium Borohydride Methanolysis(2021) Demirci, Sahin; Ari, Betul; Sengel, Sultan B.; Inger, Erk; Sahiner, NurettinHere, boric acid (H3BO3) and its dewatered form, boron trioxide (B2O3) were tested as catalysts for hydrogen (H2) evolution in the methanolysis of sodium borohydride (NaBH4) in methanol. Parameters such as catalyst types and their amounts, NaBH4 concentration, and the reaction temperature affecting the hydrogen generation rate (HGR) were studied. It has been found that H3BO3 and B2O3 catalyzed methanolysis reaction of NaBH4 follow up first-order kinetics relative to the concentration of NaBH4. Furthermore, the conversion and activity of these catalysts were examined to determine their performance in ten consecutive use. Interestingly, H3BO3 and B2O3 have demonstrated superior catalytic performances in methanolysis of NaBH4 comparing to the studies published in literature with the activation energy of respectively 22.08 kJ.mol-1, and 23.30 kJ.mol-1 in H2 production. The HGR was calculated as 6481 mL.min-1.g-1 and 5163 mL.min-1.g-1 for H3BO3 and B2O3 catalyst, respectively for 50 mg catalyst at 298 K. These results are comparably better than most metal nanoparticle catalysts used for H2 production in addition to the naturally occurring boron-based environmentally friendliness of these materials.
