Applications of Nanomaterials in Energetic Formulations: Classification, Production and Properties

In this article authors present a classification, description and competitive analyze of the main methods for production of nano scale and nanostructured materials for propellants application. Main advantages and difficulties concomitant with nanomaterials use in propellant formulations are mentioned in the beginning of the article. Specific issues related with high reactivity and pyrophoricity of nanomaterials and related risks are analyzed. Methods for nanomaterials’ surface preservation and passivation are also classified and discussed. The focus is on those methods that are most widely used, and those that are considered promising today

Purposes of Using Information by Iranian and Indian Social Science Faculty Members: A Comparative Study

The present study aims at comparing purposes of using information by Iranian and Indian Social Science Faculty Members. Totally, 487 respondents (232 from Iran and 255 from India) were randomly selected from both countries. A questionnaire measuring extent of usage for various purposes—to prepare for teaching, to carry out research, to write research proposal, to design and develop research tools, to write articles/books, to deliver special lectures, to plan program /activity, to evolve innovative techniques, to crystallize broad and vague assertions, to maintain professional competence and self- improvement—was prepared by the investigator and administered to the sample selected.  Contingency coefficient analysis was employed to verify the hypothesis. Results revealed that teaching and research as purposes of using information were higher for Iranian faculty members than Indian faculty members. In development of research tools, writing articles/books and delivering special lectures, again Iranian faculty members used much more information.  To get clarity also Iranian faculty members used more information than Indian faculty members.  It is suggested that in India more facilities should be provided to increase the information usage for various purposes

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

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

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

Planossolos e Gleissolos Utilizados na Fabricação de Cerâmica Artesanal no Semiárido de Minas Gerais

O conhecimento etnopedológico tem fornecido informações importantes sobre o modo de vida das populações rurais a respeito de suas tradições ancestrais, como a arte de elaborar peças artesanais a partir do barro advindo de solos com características próprias a esse uso. O objetivo deste trabalho foi avaliar física, química e mineralogicamente Planossolos e Gleissolos explorados para a produção de artefatos de cerâmica artesanal em Minas Gerais. Nos barreiros, foram coletados dois perfis de Planossolos (P1 e P2) e um Gleissolo (P3) usados como matéria-prima na produção artesanal de cerâmica. Foram realizadas análises físicas e químicas, limites de liquidez (LL) e plasticidade (LP), índice de plasticidade (IP) e de atividade coloidal (IA), além da mineralogia da fração argila. Os horizontes selecionados pelos ceramistas para a fabricação de cerâmica artesanal (BA, Btg e BCg, do P1; Btg1 e Btg2, do P2; e C2g e C3g, do P3) apresentaram os maiores teores de argila e silte, IP e IA, importantes para a qualidade final da cerâmica. O horizonte Cg do perfil P1 possui potencial de ser utilizado para a produção artesanal, em virtude do seu IP, superior aos dos horizontes normalmente usados, além dos teores de argila, silte e areia fina e suas características mineralógicas. A proporção ideal das frações areia, silte e argila e a porcentagem de matéria orgânica na definição de um bom material para cerâmica são difíceis de estabelecer e variam principalmente em razão de aspectos quantitativos e qualitativos da argila nos solos

An Improved Safe Method for the Synthesis of Ammonium 5-Nitrotetrazolate (ANT), a Key Intermediate for the Synthesis of Green Energetic Materials (GEMs)

Ammonium 5-nitrotetrazolate (ANT) is an important precursor for the synthesis of green energetic materials (GEMs), including lead/mercury-free environmentally benign primary explosives. The currently employed methods for the synthesis of ANT are hazardous, use an excess of organic solvents/reagents and thus generate effluent. Furthermore, these methods offer low yields of ANT as they involve multistep processes. We describe herein an improved, safe and convenient method for the synthesis of ANT, which greatly improves the process safety and product yield. The advantage of this method is that it avoids hazardous operations, such as the isolation and handling of acidic copper(II) nitrotetrazolate, an extremely sensitive explosive intermediate during the preparation of ANT. In our procedure, 5-aminotetrazole (5-AT) is diazotized with sodium nitrite and nitric acid in the presence of a copper salt. The sensitive copper acid salt thus formed from the reaction mixture is treated in situ with aqueous barium hydroxide to convert it to barium 5-nitrotetrazolate and insoluble copper oxide. Finally, the aqueous barium 5-nitro-1H-tetrazolate (BaNT) is treated with ammonium sulfate to yield ammonium 5-nitrotetrazolate (ANT) in good yield. The synthesized ANT was characterized by its physicochemical properties using spectral and thermal techniques. The purity of the ANT was measured by HPLC and ion chromatography (IC). Furthermore, the structure of ANT was confirmed by single crystal X-ray analysis

Thermal Analysis and Sensitivity Studies on Guanylurea Dinitramide (GUDN or FOX-12) Based Melt Cast Explosive Formulations

Guanylurea dinitramide (GUDN or FOX-12) is a stable salt of dinitramidic acid with good thermal stability, and is a good candidate for insensitive formulations. Thermal analysis reveals the compatibility of GUDN with benchmark explosives such as RDX and TNT in melt cast explosive formulations. The paper describes a thermal and sensitivity study of GUDN with RDX and TNT. In the present study GUDN was evaluated as a possible replacement for RDX/TNT based aluminized and non aluminized melt cast explosive formulations. The thermal properties of the composition were investigated as well as its sensitivity to impact and friction. Its thermal decomposition behavior was compared to a control composition based on RDX and TNT. The thermal and sensitivity results proved the worth of these compositions for melt cast explosive applications