Carbon,nitrogen and phosphorus stoichiometric ratios under cotton cropping systems in Australian Vertisols: a meta-analysis of seven experiments

Enhancing storage of carbon (C) in agricultural soil has been proposed as a partial solution to offset the accelerated release of greenhouse gases associated with global warming. A net loss of soil C is common in most cotton (Gossypium hirsutum L.)-based farming systems in Australian Vertisols. Some authors have suggested that an “ideal” stoichiometric ratio C:N:P:S of 10,000:833:200:143 was required for sustained C sequestration. The objective of this study was to determine the C, N, and P stoichiometric ratios that were present under cotton cropping systems sown in some typical irrigated and dryland Vertisols of Eastern Australia. Measurements were made on archived soil samples from seven experiments conducted between 1993 and 2012. Soil C sequestration was mostly negative in many of these sites or at best neutral. The archived soils were analysed for total P by digestion, and total C and N by dry combustion. The results were grouped and analysed according to four rotation types (continuous cotton systems, and cotton fb. (followed by) cereal, cotton fb. legume and cotton fb. cereal and legume, and two water management practices (irrigated and dryland) using a mixed model approach for meta-analysis of multiple experiments. Although small differences in C:N:P ratios existed among rotation types, values were much lower with irrigation (30:3:1) than in the dryland sites (263:14:1) and the “ideal” ratio (50:4:1). Low nutrient availability may not be the cause of soil C losses under irrigation but it may be one factor that inhibits C sequestration under dryland conditions.     

Comparative studies of functionalized polyacrylamide/graphite composites for the removal of direct blue 2b from aqueous solution

In this study, we prepared glucose and glucosamine-grafted polyacrylamide (PAM)/graphite composites as adsorbents and characterized by Fourier transform infrared (FT-IR), SEM/EDAX, XRD and TGA analysis. Direct blue 2b dye removal by composites was investigated using kinetic, equilibrium and thermodynamic studies by varying adsorption parameters. The results manifest that glucosamine-grafted PAM/graphite composite was an efficient adsorbent for the expulsion of dye from aqueous medium. The Freundlich isotherm fits well with the equilibrium data. The pseudo second-order model was suitable for describing the kinetic data and equilibrium attained within 60 min. Thermodynamic analysis reveals that adsorption of dye is physical, spontaneous and endothermic in nature. The recyclability study reveals that the regeneration efficiency of GA-g-PAM/graphite was maintained 85.35% up to eight cycles.     

Characterization of leptospiral serovars by randomly amplified polymorphic DNA fingerprinting

Randomly amplified polymorphic DNA (RAPD) fingerprinting of 14 laboratory strains of leptospiral serovars (serovars australis, autumnalis, ballum, bataviae, canicola, grippotyphosa, hardjoprajitno, hebdomadis, icterohaemorrhagiae, javanica, pomona, pyrogenes, panama, and tarassovi) was carried out by using a pair of primers. Each serovar had a unique and distinct fingerprint pattern. DNAs of other bacterial species, including Escherichia coli, Pasteurella multocida, Salmonella spp., Pseudomonas spp., and Klebsiella spp., did not show any amplification. RAPD fingerprinting was found to be a rapid and sensitive method for serovar identification when it was compared to DNA restriction enzyme analysis, which produced a larger number of bands that made it more difficult to compare serovars.     

Momentum-based wavelet and double wavelet neural networks for power system applications

In order to minimize the power loss and to control the voltage in the power systems, the proposed momentum-based wavelet neural network and proposed momentum-based double wavelet neural network are proposed in this paper. The training data are obtained by using linear programming method by solving several abnormal conditions. The control variables considered are generator voltages and transformer taps, and the dependent variables are generator reactive powers and load bus voltages. The IEEE 14-bus system and IEEE 30-bus system are tested using the linear programming, Levenberg–Marquardt artificial neural network, proposed momentum-based wavelet neural network and proposed momentum-based double wavelet neural network to validate the effectiveness of the proposed MDWNN method. The trained neural networks are capable of controlling the voltage, and reactive power in power systems is proved by the results with the high level of precision and speed.

     

Competitive reduction of pertechnetate (99TcO4-) by dissimilatory metal reducing bacteria and biogenic Fe(II)

The fate of pertechnetate ((99)Tc(VII)O(4)(-)) during bioreduction was investigated in the presence of 2-line ferrihydrite (Fh) and various dissimilatory metal reducing bacteria (DMRB) (Geobacter, Anaeromyxobacter, Shewanella) in comparison with TcO(4)(-) bioreduction in the absence of Fh. In the presence of Fh, Tc was present primarily as a fine-grained Tc(IV)/Fe precipitate that was distinct from the Tc(IV)O(2)·nH(2)O solids produced by direct biological Tc(VII) reduction. Aqueous Tc concentrations (<0.2 μm) in the bioreduced Fh suspensions (1.7 to 3.2 × 10(-9) mol L(-1)) were over 1 order of magnitude lower than when TcO(4)(-) was biologically reduced in the absence of Fh (4.0 × 10(-8) to 1.0 × 10(-7) mol L(-1)). EXAFS analyses of the bioreduced Fh-Tc products were consistent with variable chain length Tc-O octahedra bonded to Fe-O octahedra associated with the surface of the residual or secondary Fe(III) oxide. In contrast, biogenic TcO(2)·nH(2)O had significantly more Tc-Tc second neighbors and a distinct long-range order consistent with small particle polymers of TcO(2). In Fe-rich subsurface sediments, the reduction of Tc(VII) by Fe(II) may predominate over direct microbial pathways, potentially leading to lower concentrations of aqueous (99)Tc(IV).     

Short-Term Oxidation Studies on Nicrofer-6025HT in Air at Elevated Temperatures for Advanced Coal Based Power Plants

Several advanced air separation unit (ASU) designs being considered for use in coal gasification rely on the use of solid state mixed ionic and electronic conductors. Nicrofer-6025HT, a nickel-based alloy, has been identified as a potential manifold material to transport the hot gases into the ASUs. In the current study, isothermal oxidation tests were conducted on Nicrofer-6025HT in the temperature range of 700–900 °C for up to 24 h. The evolution of oxide scale was evaluated using SEM, XRD, and XPS. The composite surface oxide layer that formed consisted of an outer chromia-rich scale and an inner alumina scale. For the longer times at the higher temperatures evaluated, a NiCr₂O₄ spinel phase was located at the interface between the alumina and chromia. Based on the experimental results a four-step oxidation model was proposed.     

Rare earth fluorescence in NASICON type phosphate glass, Na3TiZnP3O12

The emission spectra of Pr³⁺, Eu³⁺ and Dy³⁺ doped in NASICON type phosphate glass, Na₃TiZnP₃O₁₂ (NTZP) are studied. The dopant rare earth ions occupy sites with 8–9 coordination in a highly covalent environment. For Pr³⁺ ion, calculated and observed branching ratios for lasing transitions³ P ₀→³ H _4,6 agree well and found to be 0·64 and 0·24, respectively. The emissions of Pr³⁺ show strong temperature dependence on account of Boltzmann population of the higher excited states at room temperature. The excitation spectrum of Eu³⁺ gives rise to phonon assisted side band for⁵ D ₂←⁷ F ₀ transition at higher energy side with a phonon energy maximum of 1022 cm⁻¹ and an electron phonon coupling strength (g) of 0·018. The value of phonon energy maximum agrees with infrared spectral data. The results show that observation of high energy emissions in phosphate glasses require much higherg values. The red/orange and yellow/blue transitions of Eu³⁺ and Dy³⁺, respectively show that the Eu³⁺ occupy more distorted site than Dy³⁺.     

Coating of lightweight wool fabric with nano clay for fire retardancy

Nano-kaolinite was applied to lightweight wool fabric for imparting fire retardant finish using pad batch as well as exhaust method. The effect of fire retardant treatments on the physico-mechanical properties of wool fabric was studied in detail. Nano-kaolinite incorporated fire retardant formulations showed high fire retardant performance in terms of inclined flammability test, limiting oxygen index (LOI) and thermogravimetric analysis. The characterization of nanoparticles was performed using various analytical instruments. The results inferred that nano-kaolinite treatment by both application methods is effective for improving the fire resistance of wool fabric. The treatment resulted up to 32% enhancement in fire retardant properties.