26 resultados para Rain precipitation

em Deakin Research Online - Australia


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The protein quality and physico-functional properties of Australian sweet lupin protein concentrates, prepared by isoelectric precipitation or ultrafiltration, were assessed. The ultrafiltration process resulted in a higher yield of protein than did the isoelectric precipitation process. The lupin kernel and the two lupin protein concentrates had similar essential amino acid compositions that were inferior to ideal human requirements. True digestibilities of the isoelectrically precipitated (ISO) and the ultrafiltered (UF) lupin protein concentrates were similar but significantly higher (P<0.05) than that of casein. Net protein utilisations (NPU) of the ISO and UF protein concentrates were similar but significantly lower (P<0.05) than that of casein. The UF protein concentrate had higher protein solubility than did the ISO protein concentrate (P<0.05). Low foaming capacity, low viscosity, but high emulsification capacity (particularly at low pH) were observed for lupin protein concentrates.

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This research investigates the perceived risks and perceptions of visitor experiences associated with visitation to an ecological tourist destination. The research identified a significant consumption barrier which appeared to impact significantly and reflect juxtapositions with regard to tourists’ perceived (reflective) and lived (responsive) experiences with the tourist attraction. The conflicting reports of the “over-commercialisation” of the attraction and the enjoyment of the natural experience recorded at varying recollection periods, provided valuable insight into tourist consumption barriers to the establishment of relational bonds between tourists and ecological tourist attractions.

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Some of the critical properties for a successful orthopedic or dental implant material are its biocompatibility and bioactivity. Pure titanium (Ti) and zirconium (Zr) are widely accepted as biocompatible metals, due to their non-toxicity. While the bioactivity of Ti and some Ti alloys has been extensively investigated, there is still insufficient data for Zr and titanium-zirconium (TiZr) alloys. In the present study, the bioactivity, that is, the apatite forming ability on the alkali and heat treated surfaces of Ti, Zr, and TiZr alloy in simulated body fluid (SBF), was studied. In particular, the effect of the surface roughness characteristics on the bioactivity was evaluated for the first time. The results indicate that the pretreated Ti, Zr and TiZr alloy could form apatite coating on their surfaces. It should be noted that the surface roughness also critically affected the bioactivity of these pretreated metallic samples. A surface morphology with an average roughness of approximately 0.6 microm led to the fastest apatite formation on the metal surfaces. This apatite layer on the metal surface is expected to bond to the surrounding bones directly after implantation.

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Current literature pertaining to the shape memory effect in the Fe–Mn–Si-based system is critically discussed. It is argued that the
enhanced shape memory previously attributed to NbC precipitation is mainly due to the associated thermo-mechanical treatments.
It is concluded that the thermo-mechanical processing of the alloy is the dominant factor that determines the shape memory effect in
this alloy system.

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This paper examines the effects of TiC and NbC precipitation and prior cold rolling on the shape memory behaviour of an iron-based alloy. A precipitate-free alloy was used as a reference to investigate the relative contributions of prior-deformation and precipitation on shape memory. Heat treatment of the Nb- and Ti-containing alloys at 700 °C and 800 °C resulted in carbide precipitates between 120 nm and 220 nm in diameter. Bend testing of these samples showed a marginal increase in shape memory compared to the precipitate-free alloy. Under these conditions TiC precipitation exhibited slightly better shape memory than for NbC. However, this small increase was over-shadowed by the marked increase in shape memory that can be produced by subjecting the alloys to cold rolling followed by recovery annealing. When processed in this way, fine carbides are formed in the Ti- and Nb-containing alloys during the heat treatment. For particles >25 nm in diameter the shape memory is unaffected, but, it was found that small <5 nm particles have a detrimental effect on shape memory due to pinning of the martensite plates, thereby inhibiting their reversion to austenite. The optimum shape memory was observed in the precipitate-free alloy after cold rolling and recovery annealing.

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A thorough investigation of conditions required for the precipitation of magnesium ammonium phosphate hexahydrate using magnesia as the source of magnesium was carried out and two computer models were used to make predictions as to optimum conditions for production of suitable crystal size and structure for a successful process. A process was developed and a bench scale model operated for a number of high ammonia wastes. Removal of ammonia was affected to levels of up to 97% with 94% ammonia removal being achievable consistently.

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The hot deformation behaviour of a duplex ferritic/austenitic stainless steel was studied after different deformation conditions. The results showed a strange and interesting behaviour in the strength of the material during post-deformation studies. For most deformation conditions, the flow stress of the material was un-expectedly increased after annealing of deformed structures. This phenomenon implied that microstructural hardening occurred in the material during the interpass annealing rather than the expected softening. Also, an interesting change was observed where the morphology of the austenite phase changed from stringers or layers of austenite to a widmanstätten structure. The microstructural studies suggest that the austenite was dissolved and re-precipitated during the annealing process and the hardening was mostly associated with the change in the morphology of austenite.

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The growing interest in polymeric nanofibers has been increasing the push for the development of simple and efficient nanofiber-preparation techniques. We herein describe how a conventional solution process is readapted to suit the needs for fast and efficient production of short polymeric nanofibers. Poly(ethylene-co-acrylic acid) (PEAA), a semi-crystalline polymer, was used as model. When a PEAA solution was injected into an alcoholic non-solvent while simultaneously applying high shear to the non-solvent system, PEAA nanofibers were obtained with average diameter as thin as 113 nm and length as short as 4.5 _m. The fiber diameter and length were also adjustable by varying the operating parameters. This one-step technique advances the currently available nanofabrication tools by adjusting a widely accepted concept to the nano-scale. It may constitute a viable method for large-scale production of short polymeric nanofibers.

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Specialist frugivores are the dominant consumers of mistletoe fruit in many regions and have been shown to intensify infections of host plants as a result of their rapid gut passage rates and dependence on existing infections. The role of specialist frugivores in long distance dispersal of mistletoe and establishment of new infections is unclear, and has not been explicitly evaluated previously. Here we critically examine the premise that specialists are the dominant dispersers by examining the role of an Australian mistletoe specialist (mistletoebird Dicaeum hirundinaceum Dicaeidae) in dispersing mistletoe (Amyema preissii Santalales: Loranthaceae) seeds beyond infected host stands. We use two primary lines of evidence - presence of birds using remote call recorders, and presence of dispersed seeds via surveys for defecated seeds on host branches. The observed and inferred movements of the mistletoebird were wholly restricted to habitat patches containing mistletoe, and this bird was not observed to transport seeds to nearby uninfected host stands within the study system. While mistletoe specialists may provide much of the within-stand dispersal service for mistletoes, this serves only to aggregate and intensify existing infections. We suggest that long distance dispersal of mistletoe seeds beyond existing hosts and infection centres is not performed by these dietary specialists, these services more likely to be provided by generalist frugivores and other occasional mistletoe fruit consumers.

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The alloying effect of a small amount of nickel on low alloy steel for application to flue gas desulfurization(FGD) systems was studied. The structural characteristics of the rust layer were investigated by scanning electron microscopy(SEM). The electrochemical properties were examined by means of potentiostatic polarization test, potentiodynamic polarization test, and electrochemical impedance spectroscopy(EIS) in a modified green death solution of 16.9 vol.% H2SO4+0.35 vol.% HC1 at 60°C and an acid rain solution of 6.25 X 10-5 M H2S04+5.5 X 10-3 M NaCl at room temperature. It was found that as the amount of nickel increased, the corrosion rate increased in the modified green death solution, which seemed to result from micro-galvanic corrosion between NiS and alloy matrix. In acid rain solution, the corrosion rate decreased as the amount of nickel increased due to the repulsive force of NiFe204 rust against Cl-ions by electronegativity.

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Precipitation strenghthening is one of the most important approaches for enhancing the strenght of microalloyed steels. This study has made a significant contribution in understanding the nucleation and growth mechanism of nanoscale interphase precipitates in steel during commercial processes. Atom Probe Tomography revealed the existence of nanoscale clusters with precipitates that then dictate the final strength.

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