scholarly journals High concentration hydrogen peroxide for rocket fuel applications

2020 ◽  
Vol 12 (3) ◽  
pp. 151-157
Author(s):  
George PELIN ◽  
Cornel STOICA ◽  
Cristina - Elisabeta PELIN ◽  
Raluca BALASA

This paper presents the experimental study of the distillation of hydrogen peroxide to increase the concentration of the solution, in order to use it as rocket fuel in space applications. The process of obtaining the desired concentration required for the operation of the wind tunnel model rocket engine was obtained using the vacuum distillation method. The process consists in removing a calculated value of the water content from the hydrogen peroxide solution with a concentration of 35%, thus increasing its concentration up to the value of 90%. The key factors that contribute in obtaining the desired concentration were evaluated and experimental results were compared with the calculated values.

2012 ◽  
Vol 132 (12) ◽  
pp. 1140-1145 ◽  
Author(s):  
Yuichi Takai ◽  
Yuhki Naganuma ◽  
Sho Takayanagi ◽  
Toru Sasaki ◽  
Takashi Kikuchi ◽  
...  

Nutrients ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1920 ◽  
Author(s):  
Carla Busquets-Cortés ◽  
Xavier Capó ◽  
Emma Argelich ◽  
Miguel Ferrer ◽  
David Mateos ◽  
...  

Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) can exert opposed effects depending on the dosage: low levels can be involved in signalling and adaptive processes, while higher levels can exert deleterious effects in cells and tissues. Our aim was to emulate a chronic ex vivo oxidative stress situation through a 2 h exposure of immune cells to sustained H2O2 produced by glucose oxidase (GOX), at high or low production rate, in order to determine dissimilar responses of peripheral blood mononuclear cells (PBMCs) and neutrophils on ROS and cytokine production, and mitochondrial dynamics-related proteins, pro/anti-inflammatory and anti-oxidant gene expression. Immune cells were obtained from subjects with metabolic syndrome. H2O2 at low concentrations can trigger a transient anti-inflammatory adiponectin secretion and reduced gene expression of toll-like receptors (TLRs) in PBMCs but may act as a stimulator of proinflammatory genes (IL6, IL8) and mitochondrial dynamics-related proteins (Mtf2, NRF2, Tfam). H2O2 at a high concentration enhances the expression of pro-inflammatory genes (TLR2 and IL1β) and diminishes the expression of mitochondrial dynamics-related proteins (Mtf1, Tfam) and antioxidant enzymes (Cu/Zn SOD) in PBMCs. The GOX treatments produce dissimilar changes in immune cells: Neutrophils were more resistant to H2O2 effects and exhibited a more constant response in terms of gene expression than PBMCs. We observe emerging roles of H2O2 in mitochondrial dynamics and redox and inflammation processes in immune cells.


2017 ◽  
Vol 70 ◽  
pp. 636-643 ◽  
Author(s):  
Huixin Li ◽  
Liang Ye ◽  
Xiaolin Wei ◽  
Teng Li ◽  
Sen Li

2014 ◽  
Vol 15 (4) ◽  
pp. 392-398 ◽  
Author(s):  
Wilcilene Costa Nascimento ◽  
Yasmin do Socorro Batista de Lima Gomes ◽  
Larissa Dias Alexandrino ◽  
Hilton Tulio Costi ◽  
José Otávio Carrera Silva ◽  
...  

ABSTRACT Aim The aim of this in vitro study was to evaluate the effects of different sodium fluoride (NaF) concentrations and pH values on the Knoop hardness (KHN), surface roughness (SR), and morphology of bovine incisors bleached with 35% hydrogen peroxide (HP). Materials and methods Sixty-five bovine incisors were fragmented (5 mm2 × 2 mm) and distributed in 5 groups: Control (unbleached), Low NaF/Acidic (35% HP + 1.3% NaF, pH 5.5), Low NaF/Neutral (35% HP + 1.3% NaF, pH 7.0), High NaF/ Acidic (35% HP + 2% NaF, pH 5.5), and High NaF/Neutral (35% HP + 2% NaF, pH 7.0). KHN analysis was performed with a microhardness tester under a load of 25 gf for 5 seconds. The average SR was obtained with a rugosimeter. KHN and SR were analyzed before and after treatments. For morphological analysis, specimens were dehydrated and gold-sputtered, and scanning electron micrographs were obtained and analyzed by 3 examiners with a double-blinded technique. KHN and SR results were analyzed by one-way ANOVA and Tukey's test (p < 0.05). Results Only the Low NaF/Acidic and Low NaF/Neutral groups showed significant differences between the initial and final KHN values. All bleached groups presented significant differences between the initial and final SR values. Among the bleached groups, the least and most morphological changes were shown by the High NaF/Neutral and the Low NaF/Acidic group, respectively. Conclusion Treatment with 35% HP and 2% NaF at pH 7.0 promoted the least changes in morphology, hardness and roughness among the bleached groups. Clinical significance In-office bleaching with high-concentration HP and 2% NaF at neutral pH promoted the least changes in enamel hardness, SR, and morphology compared to other treatments. How to cite this article Nascimento WC, Gomes YSBL, Alexandrino LD, Costi HT, Silva JOC Jr, Silva CM. Influence of Fluoride Concentration and pH Value of 35% Hydrogen Peroxide on the Hardness, Roughness and Morphology of Bovine Enamel. J Contemp Dent Pract 2014;15(4):392-398.


Author(s):  
Nobuo Tsujikado ◽  
Masatoshi Koshimae ◽  
Rikiya Ishikawa ◽  
Kazuki Kitahara ◽  
Atsushi Ishihara

2021 ◽  
Vol 2021.27 (0) ◽  
pp. 10A14
Author(s):  
Kazuki KAWANO ◽  
Satomi SHIMA ◽  
Hiroshi GOTODA ◽  
Yuya OHIMICHI ◽  
Shingo MATSUYAMA

2020 ◽  
Vol 13 (1) ◽  
pp. 238-245 ◽  
Author(s):  
Wenjun Fan ◽  
Bingqing Zhang ◽  
Xiaoyu Wang ◽  
Weiguang Ma ◽  
Deng Li ◽  
...  

We demonstrate the metal-free polymeric semiconductor pTTh as a selective and efficient photocathode for photoelectrochemical oxygen reduction to a high concentration of H2O2 in a cost-effective way.


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