Search

The high price of synthetic fertilisers and the price barrier for biochar as a soil amendment have encouraged the exploration of using biochar in fertiliser replacement formulations. Biochars coupled with fertilisers can be applied at lower application rates to achieve benefits in plant growth and nutrition, as well as soil biological fertility. It is necessary to evaluate the use of biochar as a fertiliser substitute. Therefore, this study investigated the comparative influences of biochars, including Acacia saligna (AS), Simcoa jarrah (SJ) and Wundowie jarrah (WJ), mineral fertiliser with microbes (MF + M), biochar-mineral complex (BMC) and their combination on mycorrhizal colonisation, growth and nutrition of wheat in a glasshouse experiment and sorghum in field conditions. BMC + MF + M treatment produced higher mycorrhizal colonisation than MF + M alone, indicating that BMC had a significant role in increasing mycorrhizal colonisation. SJ (treated with acetic acid) and MF + M treatments, as well as AS + MF + M application, showed similar effects on mycorrhizal colonisation, but lower colonisation than the BMC + MF + M treatment. Overall, the BMC + MF + M treatment supported the maximum shoot, root and total plant dry weight followed by AS + MF + M and WJ + MF + M. The MF + M treatment had the maximum shoot N and K concentrations, while BMC + MF + M application had the maximum shoot P concentration. AS + MF + M and WJ + MF + M treatments supported the maximum N uptake by wheat shoots, while BMC + MF + M supported the maximum P uptake. The results showed that biochars and BMCs could increase mycorrhizal colonisation, plant growth and nutrient uptake of wheat, particularly N, P, K, S and Zn. The field experiment confirmed that BMC application at a rate of 300 kg ha-1 could increase the yield of irrigated sorghum on a loam soil and provide better applied P use efficiency compared to a water-soluble fertiliser alone. These results indicated that biochar-based fertili

Addition of biochar produced through thermal decomposition of biomass has been seen as a strategy to improve soils and to sequester carbon (C), but wide scale implementation of the technology requires to devise innovative profitable solutions. To develop biochar utilisation with an integrated system approach, an innovative program was implemented in 2012 on a 53-ha farm in Western Australia to determine the costs and benefits of integrating biochar with animal husbandry and improvement of pastures. Biochar was mixed with molasses and fed directly to cows. The dung-biochar mixture was incorporated into the soil profile by dung beetles. We studied the changes in soil properties over 3 years. Biochar extracted from fresh dung and from the soil to a depth of 40 cm was characterised. A preliminary financial analysis of the costs and benefits of this integrated approach was also undertaken. The preliminary investigation results suggested that this strategy was effective in improving soil properties and increasing returns to the farmer. It was also concluded that the biochar adsorbed nutrients from the cow's gut and from the dung. Dung beetles could transport this nutrient-rich biochar into the soil profile. There was little evidence that the recalcitrant component of the biochar was reduced through reactions inside the gut or on/in the soil. Further research is required to quantify the long-term impact of integrating biochar and dung beetles into the rearing of cows.

In this study, we investigate the interfacial structures and chemistry of FeV2O4 (FVO)/ SrTiO3 (STO) and FeV2O4/La0.33Sr0.67MnO3/SrTiO3 (FVO/LSMO/STO) heterostructures, in which FVO is epitaxially grown on both a (001)-oriented SrTiO3 substrate and a LSMO-buffered substrate by pulsed laser deposition (PLD). By combining data from transmission electron microscopy (TEM) imaging together with high-resolution scanning transmission electron microscopy (STEM) imaging, the interfaces between FVO and STO, and FVO and LSMO are found to be coherent and semicoherent, respectively, in spite of more than 8% of strain at the interface. Energy-dispersive X-ray spectroscopy (EDS) analysis suggests that localised diffusion occurs at both the FVO/STO and the FVO/LSMO interfaces.

The effect of coating thickness on the deformation behaviour of diamond-like carbon (DLC) coatings on silicon substrates was investigated. Following nanoindentation of a 0.6 µm thick DLC coating, the subsurface microstructures were characterized and the data was compared to prior studies on a similar, but thicker coating. Indentation resulted in localized plastic compression in the coating without any through-thickness cracking. It was shown that the discontinuities in the load–displacement curves appeared at lower loads for the thinner coating. Accordingly, the silicon substrate exhibited cracking, plastic deformation and phase transformation at significantly lower loads than in the case of the thicker coating. Further, the widths, parallel to the interface, over which slip and the phase transformation zone are spread out in the substrate, was found to increase with the thickness of the coating. The mechanism responsible for the first pop-in was found to change from phase transformation in uncoated silicon to dislocation nucleation in the presence of the coating.

The effect of the presence of diamondlike carbon coatings deposited on (100) Si substrateson the deformation mechanisms operating in the silicon substrate during contact loadinghave been investigated by both cross-sectional transmission electron microscopy andmodeling of the stresses generated beneath the indenter tip. The observed subsurfacemicrostructures were correlated to the Tresca shear stress and the hydrostatic stressgenerated in the silicon substrate beneath the indenter tip. The presence of the coatingaltered the stresses generated in the substrate, and changed the deformation mechanismfrom one of principally phase transformation in uncoated Si to predominantly dislocationmotion in the silicon substrate for the diamondlike C¿Si system. The magnitude anddistribution of the shear and hydrostatic stresses in the substrate were found to depend onboth the indentation load and the thickness of the coating. Furthermore, the observedwidth of deformation, parallel to the interface, which was found to increase with coatingthickness, was correlated to the wider distribution of the Tresca shear stress in thesubstrate brought about by the presence of the coating.

We have systematically studied the flux pinning behavior of MgB2 bulks synthesized by direct diffusion of Mg into pressed pellets of high purity crystalline B powder, with and without mixing with C and SiC nanoparticles, at a reaction temperature of 850degC for 10 hrs. All of the samples showed very high purity and high density, but their microstructure and flux pinning behavior showed significant differences. It was found that the pure MgB2 agrees with the deltaTc pinning model, nano-C doped MgB2 agrees with the deltal pinning model, while the SiC+MgB2 composite agrees with the deltaepsiv pinning model (stress/strain field pinning), since the dominant micro-defects that influence the flux pinning in these three samples are different.

Phase transformations in (111) Si after spherical indentation have been investigated by cross-sectional transmission electron microscopy. Even at an indentation load of 20 mN,a phase transformation zone including the high-pressure crystalline Si phases was observed within the residual imprints. The volume of the transformation zone, as well as that of the crystalline phases increased with the indentation load. Below the transformation zone, slip was found to occur on {311} planes rather than on {111}planes, usually observed on indentation of (100) Si. The distribution of defects was asymmetric, and for indentation loads up to 80 mN, their density was significantly lower than that reported for (100) Si. The experimental observations correlated well with modeling of the applied stress through ELASTICA.

Uniform alpha-Fe2O3 submicron-sized flowers have been synthesized by a simple hydrothermal process conducted at 160 degrees C for 024 h. The crystalline structure and morphology of the as-synthesized powder have been characterized by using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and field emission scanning electron microscopy (FE-SEM). The results revealed that the highly crystalline alpha-Fe2O3 submicro-flowers were composed of nanospheres with an average size of 20-30 nm. The electrochemical performance as anode material for lithium-ion batteries was further evaluated by Cyclic voltammetry (CV) and by electrochemical impedance and charge-discharge measurements. It was demonstrated that the material could provide an initial reversible capacity of 959.6 mAh/g at a current density of 20 mA/g over the voltage range from 0.0 1 to 3.0 V. The capacity retention upon the 50th cycle was 44.4 and 35.9% at 60 and 100 mA/g, respectively. The superior electrochemical performance may be resulted from the high surface area and the small and uniform grain size.

Transition metal (Mn and Ni) doped ZnO nanocrystals with a diameter of 20 nm were fabricated by a low temperature solution processing technique. The incorporation of Ni and Mn into the ZnO lattice is evidenced by the shrinkage or expansion of the lattice parameters of ZnO in response to the transition metal dopants as determined by structure refinements. The E2 (High) phonon lines in Raman spectra of all the samples show large redshift of more than 6 cm-1 in comparison with that of the ZnO bulk single crystal. Especially, a further redshift of 3 cm-1 and broadening effect in the Raman spectra of the 5% Ni doped ZnO nanocrystals in comparison with the undoped ZnO nanocrystals indicate that the transition metal introduced defects and host disorder into the ZnO. The obtained nanocrystals are ferromagnetic at room temperature.

A novel nano-silicon/polypyrrole composite, suitable for lithium-ion battery anodes, was prepared by chemical polymerization. The cycling stability of Si/PPy electrodes was significantly improved compared to that of the bare Si anodes. The electrochemical performance of the Si/PPy electrodes is comparable to that of Si/DC nanocomposite electrodes. The vast network of the PPy matrix is a suitable environment to increase the electrical conductivity, buffer the volume change during cycling, and prevent cracking and pulverization of the Si electrode.

Carbon nanotubes (CNTs) are an excellent candidate for introducing effective pinning centres and at the same time enhancing the upper critical field of MgB2. We report on the use of a low intensity ultrasonication as a method of dispersion of CNTs into precursor magnesium and boron powder. The ultrasonication improved homogenous mixing of CNTs with the MgB2 matrix. Ultrasonication of CNT doped MgB2 resulted in a significant enhancement in the field dependence of critical current density. The density of the sample increased due to the improved adherence between CNTs and MgB2 matrix. CNTs donate carbon that is substituted for boron in MgB2.

A magnetic field of up to 12T was applied during the sintering process of pure MgB2 and carbon nanotube(CNT)dopedMgB2wires. The authors have demonstrated that magnetic field processing results in grain refinement, homogeneity, and enhancement in Jc(H) and Hirr. The extent of improvement in Jc increases with increasing field. The Jc for a 10T field processed CNTdoped sample increases by a factor of 3 at 10K and 8T and at 20K and 5T, respectively. Hirr for the 10T field processed CNTdoped sample reached 9T at 20K, which exceeded the best value of SiC dopedMgB2 at 20K. Magnetic field processing reduces the resistivity in CNTdopedMgB2, straightens the entangled CNTs, and improves the adherence between CNTs and the MgB2 matrix.

We report a systematic study on the effect of sintering temperature on the phase formation, critical current density, upper critical field and irreversibility field of nanoscale SiC doped MgB2. Bulk and Fe sheathed wires doped with different nano-SiC particle sizes have been made and heat treated at temperatures ranging from 580 to 1000 °C. A systematic correlation between the sintering temperature, normal state resistivity, RRR, Jc, Hc2, and Hirr has been found in all samples of each batch. Samples sintered at a lower temperature have a very fine and well consolidated grain structure while samples sintered at a high temperature contain large grains with easily distinguishable grain boundaries. Low temperature sintering resulted in a higher concentration of impurity precipitates, larger resistivity, higher Jc up to 15 T and lower Tc values. These samples show higher Hc2 and Hirr at T near Tc but lower Hc2 near T = 0 than samples sintered at high temperature. It is proposed that huge local strains produced by nano-precipitates and grain boundary structure are the dominant mechanism responsible for higher Hc2 at T near Tc. However, higher impurity scattering due to C substitution is responsible for higher Hc2 in the low temperature regime for samples sintered at a higher temperature. In addition to high Hc2, it is also proposed that the large number of nano-impurities serve as pinning centres and improve the flux pinning, resulting in higher Jc values at high magnetic fields up to 15 T.