57 resultados para Algae removal

em Deakin Research Online - Australia


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The string of high-profile corporate collapses recently has provided a fresh insight into many important topics and issues in Australian corporations law. Notwithstanding this, one topic that continues to receive inadequate attention both in Australia and in foreign jurisdictions is the statutory removal of  directors. In an earlier article published in this journal, one of the present authors contributed towards addressing this lack of commentary on the topic by highlighting a number of peculiarities with the provisions under the then Corporations Law regulating the removal of directors in public and proprietary companies. Since that time, the CLERP amendments to the Corporations Law (now Corporations Act 2001) in 2000 introduced some interesting changes to the provisions dealing with the removal of directors in public and proprietary companies. In this article, the authors provide an explanation and critical analysis of these changes, and consider the recent Western Australian Supreme Court decision of Allied & Mining Process Ltd v Boldbow Pty Ltd [2002] WASC 195, which deals with some of the issues raised by the authors in relation to the CLERP amendments. According to the authors, whilst some of the peculiarities raised in the earlier article no longer exist post-CLERP, the current removal provisions still raise some important questions of interpretation.

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Increasing attention is being given to the legal and governance issues relating to the removal of directors in Australian public companies. This has been due mainly to the difficulties experienced by the board of National Australia Bank in attempting to remove one of its fellow directors, and the subsequent development of public companies entering into so-called 'prenuptial agreements' with new directors, requiring that the director 'resign' if the board pass a vote of no-confidence in the director. In this article, the author revisits the area of director removal in Australian public companies for two reasons. The first reason, which covers the majority of the article, is to engage in a detailed analysis of whether the pre-nuptial agreements which some public companies have indicated that they support using to remove directors, are in fact enforceable under Australia's Corporations Act The second reason is to outline a law reform proposal to enable public companies to remove directors without requiring the vote of shareholders at a general meeting. The proposal involves providing Australia' corporate  regulator, the Australian Securities and Investments Commission (ASIC) with the power to grant relief from the statutory removal provisions to public companies, but in a way which balances the competing objectives of commercial efficiency and shareholder participation and, very importantly, encourages good corporate governance practices by companies in relation to the performance assessment  of directors.

It is in the interests of both shareholders and directors to agree on a set of ground rules for the effective supervision of companies that reconciles the rights of the owners to overall control with the much tougher demands on modern directors

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This study presents an environmental-friendly and cost effective method for the extraction of arsenic from contaminated soils.
Laboratory experiments using inorganic salts, potassium phosphate (KH2PO4), potassium chloride (KCl), potassium nitrate (KNO3), potassium sulfate (K2SO4), and sodium perchlorate (NaClO4) were evaluated as arsenic extractants. An Andosol soil was artificially contaminated with arsenite [As(III)] and arsenate [As(V)]. The soil was washed in a batch process with different salt solutions in the pH range 3–11 for 24 hours at 20◦C. Among the various potassium and sodium salts tested, KH2PO4 was found to be highly effective in extracting arsenic from As(III)-soil attaining more than 80% and 40% from As(V)-soil in neutral pH range. Other salts were particularly ineffective in extraction of arsenic from both soils. More arsenic was extracted more from the As(III)-soil than the As(V)-soil.

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Volatile organic compounds (VOCs) exist widely in both the indoor and outdoor environment. The main contributing sources of VOCs are motor vehicle exhaust and solvent utilization. Some VOCs are toxic and carcinogenic to human health, such as benzene. In this study, TiO2–SiO2 based photocatalysts were synthesized using the sol–gel method, with high surface areas of 274.1–421.1 m2/g obtained. Two types of pellets were used as catalysts in a fixed-bed reactor installed with a UV black light lamp. Experiments were conducted to compare their efficiencies in degrading the VOCs. Toluene was used as the VOC indicator. When the toluene laden gas stream passed through the photocatalytic reactor, the removal efficiencies were determined using a FTIR multi-gas analyser, which was connected to the outlet of the reactor to analyse the toluene concentrations. As the TiO2–SiO2 pellets used have a high adsorption capacity, they had dual functions as a photocatalyst and adsorbent in the hybrid photocatalysis and adsorption system. The experiments demonstrated that the porous photocatalyst with very high adsorptive capacity enhanced the subsequent photocatalysis reactions and lead to a positive synergistic effect. The catalyst can be self-regenerated by photocatalytic oxidation of the adsorbed VOCs. When the UV irradiation and feeding gas is continuous, a destruction efficiency of about 25% was achieved over a period of 20 h. Once the system was designed and operated into adsorption/regeneration mode, a higher removal efficiency of about 55% was maintained. It was found that the catalyst pellets with a higher surface area (421 m2/g) achieved higher conversion efficiency (100%) for a longer period than those with a lower surface area. A full spectrum scan was carried out using a Bio-rad Infrared spectrometer, finding that the main components of the treated gas stream leaving the reactor, along with untreated toluene, were CO2 and water. The suspected intermediates of aliphatic hydrocarbons and CO were found in minimal amounts or were non detectable. The kinetic rate constants were calculated from the experimental results, it appeared that the stronger adsorption capacity, i.e. larger specific surface area, the higher conversion efficiency would be achieved.


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Nodularia spumigena periodically proliferates to cause toxic algal blooms with some aquatic animals enduring and consuming high densities of the blue green algae or toxic lysis. N. spumigena contains toxic compounds such as nodularin and lipopolysaccharides. This current work investigates physiological effects of exposure from bloom conditions of N. spumigena cells and a post-bloom lysis. Biochemical and antioxidative biomarkers were comparatively studied over an acute 3-day exposure. In general, a post-bloom N. spumigena lysis caused opposite physiological responses to bloom densities of N. spumigena. Specifically, increases in glutathione (GSH) and glutathione peroxidase (GPx) and decreases in glutathione S-transferase (GST) were observed from the N. spumigena lysis. In contrast, N. spumigena cell densities decreased GSH and increased GST and lipid peroxidation (LPO) in mussels. Findings also suggest that at different stages of a toxic bloom, exposure may result in toxic stress to specific organs in the mussel.

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The effectiveness of various photocatalysts including titanium dioxide and other oxidants was investigated in a solar powered UV photocatalytic oxidation system for colour removal in dyeing effluent. A semi-empirical constant model and guidelines were developed to assist the design and to evaluate the full scale of the system.

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Biosolids were used to remove zinc, manganese and cyanide from mining wastewaters. The effect of aqueous parameters and reaction variables on contaminant biosorption was quantified. The mechanism of removal was adsorption onto amine and carboxyl functional groups. Immobilisation was investigated to overcome problems of swelling and disintegration of the biosolids.