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Catalytic effects of Cu-Co~* on the thermal decomposition of AN and AN/KDN based green oxidizer and propellant samples

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Defence Technology（防务技术） 2018年第3期14卷 250-260页

作者： Pratim Kumar puran chandra Joshi Rajiv Kumar Shelly Biswas Department of Space Engineering & Rocketry Birla Institute of Technology Department of Mechanical Engineering Vidya Vihar Institute of Technology

This paper presents the catalytic effects of Cu-Co~* catalyst on the decomposition of AN and AN/KDN based oxidizer and propellant samples. Ozawa-Flynn-Wall(OFW) iso-conversional method was used for the kinetic studies and to compute the activation energy(Ea) values for various decomposition steps of the prepared oxidizer and propellant samples in the temperature range of 50 e500C. TG-DTG experiments were carried out for both oxidizer and propellant samples at the heating rates of 3, 5, and 10C/min. AN/KDN based oxidizer samples were prepared by an evaporative co-crystallization method. Citric acid sol-gel method was used for the synthesis of Cu-Co~* catalyst. The propellant sample contains HTPB as the fuel binder along with other ingredients such as TDI, DOA, and Glycerol. The Cu-Co~* catalyst was used as 2% by weight to the total weight of catalyzed oxidizer and propellant samples. It was observed from the present study that, Cu-Co~* catalyst helps in reducing the Ea values for AN and AN based propellant samples. However, with the percentage increment of KDN in the AN crystals, Ea value ***, it was observed that Cu-Co~* catalyst stabilizes the initial partial decomposition of KDN.

关键词：催化氧化剂催化效果热分解 Cu 燃料取样 TG-DTG 催化剂

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Cu–Co–O nano-catalysts as a burn rate modifier for composite solid propellants

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Defence Technology（防务技术） 2016年第4期12卷 297-304页

作者： D. Chaitanya Kumar RAO Narendra YADAV puran chandra JOSHI Space Engineering and Rocketry Birla Institute of Technology Mesra Ranchi 835215 India

Nano-catalysts containing copper–cobalt oxides(Cu–Co–O) have been synthesized by the citric acid(CA) complexing method. Copper(II) nitrate and Cobalt(II) nitrate were employed in different molar ratios as the starting reactants to prepare three types of nano-catalysts. Well crystalline nano-catalysts were produced after a period of 3 hours by the calcination of CA–Cu–Co–O precursors at 550 °C. The phase morphologies and crystal composition of synthesized nano-catalysts were examined using Scanning Electron Microscope(SEM), Energy Dispersive Spectroscopy(EDS) and Fourier Transform Infrared Spectroscopy(FTIR) methods. The particle size of nano-catalysts was observed in the range of 90 nm–200 nm. The prepared nano-catalysts were used to formulate propellant samples of various compositions which showed high reactivity toward the combustion of HTPB/AP-based composite solid propellants. The catalytic effects on the decomposition of propellant samples were found to be significant at higher temperatures. The combustion characteristics of composite solid propellants were significantly improved by the incorporation of nano-catalysts. Out of the three catalysts studied in the present work, Cu Co-I was found to be the better catalyst in regard to thermal decomposition and burning nature of composite solid propellants. The improved performance of composite solid propellant can be attributed to the high crystallinity, low agglomeration and lowering the decomposition temperature of oxidizer by the addition of Cu Co-I nano-catalyst.

关键词： Metal oxides Nano-catalysts Solid propellant Burn rate Surface morphology Thermal analysis

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Crop productivity,soil health,and energy dynamics of Indian Himalayan intensified organic maize-based systems

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International Soil and Water Conservation Research 2021年第2期9卷 260-270页

作者： Raghavendra Singh Subhash Babu R.K.Avasthe Gulab Singh Yadav Anup Das K.P.Mohapatra Amit Kumar Vinod K.Singh puran chandra ICAR-National Organic Farming Research Institute GangtokSikkim737102India Division of Agronomy ICAR-Indian Agricultural Research InstituteNew Delhi110012India ICAR Research Complex for NEH Region Tripura CentreLembucherraTripura799210India ICAR-National Bureau of Plant Genetic Resources New Delhi110012India

The sustainability of prevailing maize-fallow system in rainfed ecosystems of the Eastern Himalayan region(EHR)of India is often questioned due to poor economic return and negative impact on soil ***,the six cropping systems,maize-fallow(M-F),maize t cowpea-rapeseed(M t C-Rs),maize t cowpea-buckwheat(M t C-Bw),maize t cowpea-barley(M t CeB),maize t cowpea-garden pea(M t C-GP)and maize t cowpeaerajmash(M t C-R)in the main plot and three soil moisture conservation measures,no-mulch(NM),maize stover mulch(MSM)and maize stover t weed biomass mulch(MSM t WBM)in sub-plot were evaluated for four consecutive years(2014-18)at a Research Farm in fixed plot *** indicated that cowpea co-culture with maize and inclusion of winter crop increased maize yield by 6.2e23.5%over *** the systems,the M t C-GP recorded the highest crop *** residual effect of MSM t WBM increased maize grain yield by 19.1%over *** of maize t cowpea-winter crops significantly improved the available N(3.2e12.9%),P(3.6 e12.7%),K(1.9e26.3%),organic carbon(9.2e16.8%),microbial biomass carbon-MBC(15.2e43.9%)and dehydrogenases-DHA(17.2e42.3%)in soil at 0e15 cm depth as compared to *** M t C-GP also recorded maximum net return(US$2460 ha1),benefit:cost(B:C)ratio(2.86)and energy use efficiency(7.9%).The MSM t WBM recorded higher net return(US$1680 ha1)and B:C ratio(2.46)over ***,cowpea t maize-garden pea(M t C-GP)along with the application of MSM t WBM is a sustainable production practice to intensify the organically managed maize-fallow system in rainfed regions of the EHR of India and other similar ecosystems.

关键词： Crop intensification Energy productivity Gross return Soil health Water productivity

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