Synthesis of pyrazolo[4′,3′:5,6]pyrazino[2,3-c]pyrazoles and pyrazolo[4′,3′:5,6]pyrazino[2,3-d]pyrimidines and their application to polyester fibres

4-Nitroso-1-phenyl-3-methyl-5-aminopyrazole ( 1 ) was condensed with ethylcyanoacetate ( 2 ), malononitrile ( 4a ) and 2-cyanomethylbenzimidazole ( 4b ) to yield 6-hydroxy-5-cyano, 6-amino-5-cyano and 6-amino-5-(benzimidazol-2-yl)-3-methylpyrazolo [3,4-b]pyrazines 3, 5a and 5b , respectively. 5-Cyano-6-chloro derivative 6 obtained from 3 was converted to 3-aminopyrazolo[4′,3′:5,6]pyrazino[2,3-c]pyrazoles 8a and 8b by the treatment with hydrazin hydrate ( 7a ) and phenylhydrazine ( 7b ), respectively. Compound 5a was treated with formamide ( 9a ), urea ( 9b ) and thiourea ( 9c ) to give 4-aminopyrazolo[4′,3′:5,6]pyrazino[2′3′-d]pyrimidines 10a–10c. With refluxing acetic anhydride compounds 8a, 8b and 10a gave corresponding acetamido derivatives 8c, 8d and 10d. Compound 5a was treated with ethylorthoformate ( 11 ), acetic anhydride ( 12 ) or benzoylchloride ( 13 ) to give fused benzimidazopyrazolo[4′,3′:5,6]pyrazino[2′,3′-d]pyrimidines, viz., benzimidazol[1,2-c]pyrazolo[4,3-g]pteridines ( 14a–14c ). Some of the compounds 8, 10 and 14 were applied to polyester as disperse dyes and their fastness properties were studied.     

Preparation and properties of acrylonitrile–butadiene rubber–graphene nanocomposites

The graphene oxide (GO) was prepared by sonication‐induced exfoliation from graphite oxide, which was produced by oxidation from graphite flakes with a modified Hummer's method. The GO was then treated by hydrazine to obtain reduced graphene oxide (rGO). On the basis of the characterization results, the GO was successfully reduced to rGO. Acrylonitrile–butadiene rubber (NBR)–GO and NBR–rGO composites were prepared via a solution‐mixing method, and their various physical properties were investigated. The NBR–rGO nanocomposite demonstrated a higher curing efficiency and a change in torque compared to the gum and NBR–GO compounds. This agreed well with the crosslinking density measured by swelling. The results manifested in the high hardness (Shore A) and high tensile modulus of the NBR–rGO compounds. For instance, the tensile modulus at a 0.1‐phr rGO loading greatly increased above 83, 114, and 116% at strain levels of 50, 100, and 200%, respectively, compared to the 0.1‐phr GO loaded sample. The observed enhancement was highly attributed to a homogeneous dispersion of rGO within the NBR matrix; this was confirmed by scanning electron microscopy and transmission electron microscopy analysis. However, in view of the high ultimate tensile strength, the NBR–GO compounds exhibited an advantage; this was presumably due to strong hydrogen bonding or polar–polar interactions between the NBR and GO sheets. This interfacial interaction between GO and NBR was supported by the marginal increase in the glass‐transition temperatures of the NBR compounds containing fillers. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42457.     

Soil aggregation and carbon and nitrogen stabilization in relation to residue and manure application in rice–wheat systems in northwest India

Soil organic matter (SOM), besides influencing carbon (C) transfer between soils and atmosphere, impacts soil functional ability and its response to environmental and anthropogenic influences. We studied the impact of continuous application of rice straw and farmyard manure (FYM) either alone or in conjunction with inorganic fertilizers on aggregate stability and distribution of C and nitrogen (N) in different aggregate fractions after 7 years of rice–wheat cropping on a sandy loam soil. Macroaggregates (>0.25 mm) constituted 32.5–54.5% of total water stable aggregates (WSA) and were linearly related (R ² = 0.69) to soil organic carbon content. The addition of rice straw and FYM significantly (P < 0.05) improved the formation of macroaggregates with a concomitant decrease in the proportion of microaggregates at all the three sampling depths (0–5, 5–10 and 10–15 cm). Macroaggregates had higher C and N density as compared to microaggregates. Application of rice straw and FYM improved C and N density in different aggregate sizes and the improvement was greatest in plots that received both rice straw and FYM each year. Application of FYM along with inorganic fertilizer resulted in a net C sequestration of 0.44 t ha⁻¹ in the plough layer after 7 years of rice–wheat cropping. Carbon sequestration was greater (1.53 t ha⁻¹) when both rice straw and FYM along with inorganic fertilizers were applied annually. It is concluded that addition of rice straw and FYM in rice–wheat system improves soil aggregation and enhances C and N sequestration in macroaggregates. This will help in sustainable rice–wheat productivity in the region.     

Sustaining Urban Water Supplies in India: Increasing Role of Large Reservoirs

Urban water demand is rapidly growing in India due to high growth in urban population and rapid industrialization. Meeting this demand is a big challenge for the urban planners in India. Incidentally, the large urban areas are experiencing faster growth in population, and most of them are in arid and semi arid regions, which are naturally water-scarce. As a result, water supplies from local water resources including aquifers are falling far short of the high and concentrated demands in most urban areas. Under such situations, these large cities have to rely on distant large reservoirs. The analysis of 302 urban centers shows that cities with larger population size have much higher level of dependence on surface water sources. Also, greater the share of surface water in the city water supplies, higher was the level of per capita water supply. Multiple regression models are estimated for Class I cities and Class II towns in India. The results show that Population Elasticity of Water Supply (PEWS) change with time and space—for Class I cities it was 1.127 in 1988, whereas that with respect to 1999 population is 1.289. It also shows that Class I cities have better water supply (PEWS is 1.127 in 1988 and 1.289 in 1999) than Class II towns (PEWS is 0.396 in 1988 and 0.675 in 1999). Given the structure and pattern of urban population growth, economic conditions and water demands, large reservoirs will have a much bigger role in meeting urban water supply needs.     

Metabolomics of photobiological hydrogen production induced by CCCP in Chlamydomonas reinhardtii

The green alga Chlamydomonas reinhardtii can produce hydrogen gas (H₂) in the presence of the proton uncoupler carbonyl cyanide m-chlorophenyl hydrazone (CCCP). The addition of 15 μM CCCP to the algal cultures led to 13-fold increase in H₂ photoproduction compared to the control cultures without CCCP treatment. CCCP completely inhibited the photochemical activity of photosystem (PS) II under illumination. In order to better understand metabolic conditions necessary for sustained H₂ production, we have used gas chromatography coupled to time-of-flight mass spectrometry (GC-TOF) for metabolomics analysis that is independent of nutritional stress, specifically, sulfur deprivation, which had been used previously to induce H₂ photoproduction. Even 10 min after addition of CCCP, metabolites from many metabolic modules were found drastically decreased, including levels of free amino acids, unsaturated free fatty acids and nucleotides. During prolonged CCCP exposure H₂ production was found to be stable for at least 12 h with a continued increase in levels of free fatty acids. These results indicate that CCCP might become a useful treatment for production of biohydrogen in reactors. The increase in fatty acid production might then be a useful addition for production of carbon-derived biofuels.     

Ferrofluid Lubrication of a Journal Bearing Considering Cavitation

Ferrohydrodynamic lubrication in journal bearings by considering cavitation boundary conditions is studied. It is assumed that the magnetization vector is not parallel to the magnetic field vector. Various bearing characteristics have been studied and it is seen that qualitative behavior of these characteristics remains similar to that in the case of non-ferromagnetic fluid. However, a significant quantitative enhancement of these characteristics is observed.     

Design of safer agricultural equipment: Application of ergonomics and epidemiology

A vast majority of the world's workers are employed in agricultural activities and are exposed to a wide variety of hazards. Since agriculture is primarily decentralised activity, it is often difficult to set and implement work safety norms and standards. While standards can be set for equipment manufactured in large factories, it is not easy to monitor its condition in use. For equipment fabricated in small workshops or by the farmers themselves, it becomes very difficult to ensure that design standards are adhered to especially when the users of equipment are hired labourers on daily wages.

This paper presents the results of an epidemiological study to determine the main causes of injuries among farmers in nine villages in the state of Haryana in Northern India. The study revealed that the largest number of traumatic injuries are caused by fodder cutting machines and threshers. The designs of these machines have been made safer using ergonomics principles. A large number of minor injuries are caused by hand tools.     

High-temperature effects in hypersonic flows

The hypersonic (M=25) flow past a 10° right circular cone at 0° angle of attack has been computed using an implicit, noniterative, finite-difference scheme for the Parabolized Navier-Stokes (PNS) equations. Three different gas models have been considered in the study — (1) ideal gas (γ = constant), (2) equilibrium air, and (3) five species (N₂, O₂, NO, N, O) chemical nonequilibrium air. For the nonequilibrium air case, three different models have been considered — (a) one in which the constituent species have no internal structure (i.e., species are ideal gases), (b) one in which the constituent species have internal structure (i.e., species are thermally perfect gases), and (c) one in which the species have internal structure and their thermodynamic properties have been obtained from quantum mechanical and spectroscopic calculations.     

Effect of doping concentration on normal state resistivity of La2 −x (Ba,Sr) x CuO4 superconductors

Based on free electron layered electron gas model of quasi two dimensional CuO₂ layers in La(Ba/Sr)CuO superconductors a model potentialV(q) is developed earlier with the electron-electron and electron-phonon interactions. The model approach facilitates the dielectric functions and the dispersion relations of 2D acoustic phonon and plasmon modes. We have then worked out the coupling strength (γ) linking electrons to the 2D acoustic phonon mode (ħω_) from the residue at the pole ofV(q). Furthermore, the scattering time (τ _e−ph) during electron-phonon interaction (EPI) for this simplified system is also estimated. The contribution to the normal state in plane resistivity due to EPI is then evaluated. Finally, the variations ofτ andρ is studied with the doping concentration (x) and temperature (T) and the results obtained by us show reasonably good agreement with the available experimental data.