Synthesis and Characterisation of Diaryl Furoxans

The paper discusses the synthesis, characterisation, and performance evaluation of diarylfuroxans namely, bis-phenyl-3,4-furoxan (5) and bis-(4’-nitrophenyl)-3,4-furoxan (6). Themolecules have been synthesised on the lines of reported method by cyclodimerisation of thenitrile oxides generated from benzaldoxime and p-nitro benzaldoxime, respectively. The synthesisedfuroxans (5 ) and (6) were characterised by the elemental analysis, UV, IR, and 1H NMRspectroscopy. The hazard characteristics (impact and friction sensitivity) confirm that thecompounds are safe to handle. The oxygen balance, velocity of detonation and detonationpressure have been computed. The detonation velocity and pressure along with oxygen balanceincreased with the substitution of nitro group in the benzene ring, as expected. Thethermogravimetric studies on promising compound (6) brings out that maximum weight lossoccurs at decomposition temperature of 259–260 °C

Backcross breeding in groundnut (Arachis hypogaea L.)

Rust caused by Puccinia arachidis Speg. is the most serious disease of groundnut and causes substantial yield loss and reduces the fodder and seed quality. Recombinant inbred lines (F6) were generated by SSD method from cross GPBD-5 x GPBD-4 and the rust resistant plants were backcrossed to the recurrent parent (GPBD-5) to develop a backcross population (BC1F4). The objective ofthis experiment was to study the possibilities of linkage break-down between yield component traits and rust resistance in groundnut. Analysis of data revealed that there was a shift in correlation from negative (F6) to positive significant direction (BC1F4) between pod yield per plant with plant height and between plant height with number of primary branches. Similarly there was linkage break-down between negative significant to positive significant association of number of primary branches with number of pods per plant, kernel yield per plant and shelling percent at both genotypic and phenotypic levels. Altogether a desirable shift in association and the proof of broken repulsion phase linkage and release of concealed variability, which is useful in plant breeding, provides a lot of scope for selection. Unchanged negative association between pod yield per plant with reaction to rust and shelling percent in both phenotypic and genotypic level in both the populations, indicated the operation of strong linkage blocks and which requires an intensive selection to combine disease resistance with yield. Otherwise inter-mating of highly extreme segregants in the populations also would cause breakage of these stubborn linkages. Thus, for yield component traits, backcrossing of selected plants is more rewarding than the single cross and advance by single seed decent method of breeding in groundnut

Locating farmer-based knowledge and vested interests in natural resource management: the interface of ethnopedology, land tenure and gender in soil erosion management in the Manupali watershed, Philippines

This paper examines local soil knowledge and management in the Manupali watershed in the Philippines

Genetic variability and marker detection for rust resistance in recombinant inbred lines and backcross inbred lines of groundnut (Arachis hypogaea l.)

A F6 mapping population and backcross populations (BC1F4 and BC2F3 BC3F2) were developed from the cross between the susceptible parent GPBD-5 and resistant parents ICGV 86699 and ICGV 99005 to dissect the genetic variation and SSR markers linked to the rust resistance in groundnut. Genetic variability revealed that there were highly significant differences among recombinants for rust reaction. Less differences were observed between PCV and GCV for rust reaction in both crosses, which indicated a greater role of genetic components. High values of heritability (>80%) genetic advance and-genetic advance as percent mean was observed for rust reaction in F6 and backcross populations. Bulk segregant analysis in the segregating populations of both crosses (GPBD-5 x ICGV 86699 and GPBD-5 x ICGV 99005) indicated Tc4g10 marker was putatively linked to the rust resistant gene. The association of the putative marker identified based on DNA pooling from the selected segregants was established by single marker analysis (SMA). In the F6 population of both crosses GPBD-5 x ICGV 86699 and GPBD-5 x ICGV 99005, the Tc4glO marker accounted for 72.40% and 50.60% total variation, respectively. Tc4g10 marker accounted for 67.10%,38.40% and 61.30% total variation in the cross GPBD-5 x ICGV 86699, and the same marker accounted for 73.8%, 54.7% and 84.4% total variation in the cross GPBD-5 x ICGV 99005 in BC1F4, BC2F3 and BC3F2, respectively. This marker can be used in marker assisted selection for rust resistance in groundnut improvement programs

Initial Steps of Thermal Decomposition of Dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate Crystals from Quantum Mechanics

Dihydroxylammonium 5,5?-bistetrazole-1,1?-diolate (TKX-50) is a recently synthesized energetic material (EM) with most promising performance, including high energy content, high density, low sensitivity, and low toxicity. TKX-50 forms an ionic crystal in which the unit cell contains two bistetrazole dianions {c-((NO)N3C)-[c-(CN3(NO)], formal charge of ?2} and four hydroxylammonium (NH3OH)+ cations (formal charge of +1). We report here quantum mechanics (QM)-based reaction studies to determine the atomistic reaction mechanisms for the initial decompositions of this system. First we carried out molecular dynamics simulations on the periodic TKX-50 crystal using forces from density functional based tight binding calculations (DFTB-MD), which finds that the chemistry is initiated by proton transfer from the cation to the dianion. Continuous heating of this periodic system leads eventually to dissociation of the protonated or diprotonated bistetrazole to release N2 and N2O. To refine the mechanisms observed in the periodic DFTB-MD, we carried out finite cluster quantum mechanics studies (B3LYP) for the unimolecular decomposition of the bistetrazole. We find that for the bistetrazole dianion, the reaction barrier for release of N2 is 45.1 kcal/mol, while release of N2O is 72.2 kcal/mol. However, transferring one proton to the bistetrazole dianion decreases the reaction barriers to 37.2 kcal/mol for N2 release and 59.5 kcal/mol for N2O release. Thus, we predict that the initial decompositions in TKX-50 lead to N2 release, which in turn provides the energy to drive further decompositions. On the basis of this mechanism, we suggest changes to make the system less sensitive while retaining the large energy release. This may help improve the synthesis strategy of developing high nitrogen explosives with further improved performance

Potential negative consequences of geoengineering on crop production: A study of Indian groundnut

Geoengineering has been proposed to stabilize global temperature, but its impacts on crop production and stability are not fully understood. A few case studies suggest that certain crops are likely to benefit from solar dimming geoengineering, yet we show that geoengineering is projected to have detrimental effects for groundnut. Using an ensemble of crop-climate model simulations, we illustrate that groundnut yields in India undergo a statistically significant decrease of up to 20% as a result of solar dimming geoengineering relative to RCP4.5. It is somewhat reassuring, however, to find that after a sustained period of 50 years of geoengineering crop yields return to the nongeoengineered values within a few years once the intervention is ceased

Towards New Directions in Oxidizers/Energetic Fillers for Composite Propellants: an Overview

There is continued interest in the development of safe and reliable composite propellant formulations using modern energetic ingredients such as energetic oxidizers/energetic ingredients, energetic binders, and energetic ballistic modifiers. There are continued efforts by energetic materials researchers, scientists, technologists and engineers to design composite propellant formulations with better ballistic properties than conventional formulations. The efforts in many research and development (R & D) laboratories all over the world are aimed at utilizing modern oxidizers/ energetic fillers for the development of composite propellant formulations for both space and defence applications. Composite propellants are considered to be the major source of chemical energy for rockets and missiles. Energetic oxidizers/fillers play vital roles in the preparation or manufacture of composite propellant formulations. Various energetic oxidizers/fillers have been developed during the last five decades to address environmental safety, high energy and processing conditions. In this article, the authors have reviewed the characteristic properties of the energetic oxidizers/fillers used in the preparation of composite propellants. The characteristic properties of the energetic ingredients play an important role in the preparation of composite propellant formulations with the desired mechanical properties. The advantages and disadvantages of various energetic oxidizers/ingredients for specific and potential propellant applications are also highlighted throughout the course of this review article. The future direction in composite propellant formulations calls for the development of green propellant formulations. Efforts will continue to seek alternative and more energetic oxidizers/fillers in comparison to conventional oxidizers. There is an urgent need to replace conventional oxidizers such as ammonium perchlorate with eco-friendly ingredients

Synthesis and characterization of methyl nitramino -2, 4, 6-trinitrobenzenes using bismuth nitrate pentahydrate as an eco friendly nitrating agent

208-210This study presents synthesis of 2,4,6-trinitrophenylmethyl- nitramine (3a) 2,4,6-trinitro-1,3-di(methylnitramino) benzene (3b) and 2,4,6-trinitro-1,3,5-tris(methylnitramino) benzene (3c) by nitration of 2,4,6-trinitro-N-methylaniline (2a), 2,4,6-trinitro- 1,3-di(methylamino) benzene (2b) and 2,4,6-trinitro-1,3,5-tris(methylamino) benzene (2c) using bismuth nitrate pentahydrate in tetrahydrofuran adsorbed on silica gel and fly ash as solid supports under microwave irradiation. An eco-friendly nitration approach used in synthesis of target compounds (3a-3c) is of interest for the production of high energy materials