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RISS 인기검색어
- 검색키워드
- 저자 : B.V.S. Jyoti (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
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Rheological Characterization of Hydrogen Peroxide Gel Propellant
B.V.S. Jyoti,Seung Wook Baek 한국항공우주학회 2014 International Journal of Aeronautical and Space Sc Vol.15 No.2
An experimental investigation on the rheological behavior of gelled hydrogen peroxide at different ambient temperature (283.15, 293.15 and 303.15 K) was carried out in this study. The gel propellant was rheologically characterized using a rheometer, in the shear rate ranges of 1 to 20 s<SUP>-1</SUP>, and 1 to 1000 s<SUP>-1</SUP>. Hydrogen peroxide gel was found to be thixotropic in nature. The apparent viscosity value with some yield stress (in-case of shear rate 1 to 20 s<SUP>-1</SUP>) drastically fell with the shear rate. In the case of the shear rate range of 1 to 20 s<SUP>-1</SUP>, the apparent viscosity and yield stress of gel were significantly reduced at higher ambient temperatures. In the case of the shear rate range of 1 to 1000 s<SUP>-1</SUP>, no significant effect of varying the ambient temperature on the gel apparent viscosity was observed. The up and down shear rate curves for hydrogen peroxide gel formed a hysteresis loop that showed no significant change with variation in temperature for both the 1 to 20 s<SUP>-1</SUP> and the 1 to 1000 s<SUP>-1</SUP> shear rate ranges. No significant change in the thixotropic index of gel was observed for different ambient temperatures, for both low and high shear rates. The gel in the 1 to 20 s<SUP>-1</SUP> shear rate range did not lead to a complete breakdown of gel structure, in comparison to that in the 1 to 1000 s<SUP>-1</SUP> shear rate range.
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Rheological Characterization of Hydrogen Peroxide Gel Propellant
Jyoti, B.V.S.,Baek, Seung Wook The Korean Society for Aeronautical and Space Scie 2014 International Journal of Aeronautical and Space Sc Vol.15 No.2
An experimental investigation on the rheological behavior of gelled hydrogen peroxide at different ambient temperature (283.15, 293.15 and 303.15 K) was carried out in this study. The gel propellant was rheologically characterized using a rheometer, in the shear rate ranges of 1 to $20s^{-1}$, and 1 to $1000s^{-1}$. Hydrogen peroxide gel was found to be thixotropic in nature. The apparent viscosity value with some yield stress (in-case of shear rate 1 to $20s^{-1}$) drastically fell with the shear rate. In the case of the shear rate range of 1 to $20s^{-1}$, the apparent viscosity and yield stress of gel were significantly reduced at higher ambient temperatures. In the case of the shear rate range of 1 to $1000s^{-1}$, no significant effect of varying the ambient temperature on the gel apparent viscosity was observed. The up and down shear rate curves for hydrogen peroxide gel formed a hysteresis loop that showed no significant change with variation in temperature for both the 1 to $20s^{-1}$ and the 1 to $1000s^{-1}$ shear rate ranges. No significant change in the thixotropic index of gel was observed for different ambient temperatures, for both low and high shear rates. The gel in the 1 to $20s^{-1}$ shear rate range did not lead to a complete breakdown of gel structure, in comparison to that in the 1 to $1000s^{-1}$ shear rate range.
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Hypergolicity and ignition delay study of pure and energized ethanol gel fuel with hydrogen peroxide
Jyoti, B.V.S.,Naseem, Muhammad Shoaib,Baek, Seung Wook Elsevier 2017 Combustion and flame Vol.176 No.-
<P><B>Abstract</B></P> <P>An experimental study of hypergolicity and ignition delay of pure and energized gelled ethanol with hydrogen peroxide was carried out. Experimental drop test results were obtained and discussed by using Photron high speed camera imaging. This study represented a sufficient repeatability of ignition delay for hypergolic gel bipropellant development. Gelled ethanol fuel (pure and energized with nano-Al/B/C particle substitution) mixture with metal catalysts were formulated to examine its hypergolicity with ignition delays on the order of 1–30ms in most of cases, which are comparable with the existing liquid hypergolic bipropellant systems. The minimum ignition delay time was recorded for boron case at 1.33ms. And the calculated activation energy for the gelled ethanol fuel with pure and energetic particle substitution system resided within the range of 7–13kJ/mole along with shear thinning behavior. Temperature profile also indicated an exothermic nature of the propellant system with 1000 to 1600K recorded. Parameters such as apparent viscosity of the fuel, drop height and drop volume also played an important role for the hypergolicity of the system in a drop experimentation. It was also observed that the formation of a cage encapsulating the high temperature gases in a network formed by the gelling agent could result in a longer ignition delay.</P>
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Characteristic white light emission via down-conversion SrGdAlO4:Dy3+ nanophosphor
Anju Hooda,S.P. Khatkar,Avni Khatkar,Sangeeta Chahar,Sushma Devi,Jyoti Dalal,V.B. Taxak 한국물리학회 2019 Current Applied Physics Vol.19 No.4
An efficient and cost-effective technique, solution combustion synthesis was used to synthesize Dy3+ doped SrGdAlO4 nanophosphor utilizing urea as a suitable fuel. The tetragonal phase and nano-crystallinity of the synthesized phosphor belonging to I4/mmm space group was confirmed by powder X-ray diffraction (PXRD) and transmission electron microscope (TEM) technique respectively. Various crystal structure parameters and refined atomic positions of host matrix and SrGd0.95Dy0.05AlO4 nanophosphor were determined by Rietveld refinement. The two intense bands i.e. blue and yellow bands were observed in photoluminescence emission spectrum recorded at 352 nm excitation wavelength, associated to transitions 4F9/2→6H15/2 (484 nm) and 4F9/2→6H13/2 (575 nm) respectively. Photometric characterizations revealed the emission of white color by the synthesized nanophosphor proving its wide applications in WLEDs (white light emitting diodes). Band gap values calculated using diffuse reflectance spectra (DRS) were found to vary in the range of 5.50 eV–5.59 eV for host and doped lattice system. Keeping in mind, the concentration quenching phenomenon, SrGd0.95Dy0.05AlO4 was considered as optimized nanophosphor for WLEDs.
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