178 research outputs found

    Risk and Knowledge in the context of Organizational Risk Management

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    This paper helps us to understand the emerging concept of knowledge management by exploring the relation between risk and knowledge. It tries to determine whether a logical relation between risk and knowledge indeed exists or not. The preliminary work on the above question reveals that such a relation does exist; however, there are some indications that worry the decision makers. Therefore, in this regard, various authors/scholars from other disciplines like Informatics, Economics, Organizational Behavioral Sciences, and Social Psychology, have importantly emphasized on the scrutiny of relationship between risk and knowledge management. Similarly, experts of information technology engage themselves in finding out risks involved in data mining, information exploration, and knowledge. Thus it is essential to express that the data and knowledge is being captured at all levels to measure risk management. Key word: Risk, Risk Management, Knowledge, Organizational Risk Management

    Ta/TiO2-and Nb/TiO2-Mixed Oxides as Efficient Solar Photocatalysts: Preparation, Characterization, and Photocatalytic Activity

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    Ta/TiO2- and Nb/TiO2-mixed oxides photocatalysts were prepared by simple impregnation method at different TiO2 : Nb or Ta mass ratios of 1 : 0.1, 1 : 0.5, and 1 : 1, followed by calcination at 500∘C. The prepared powders have been characterized by XRD, XPS, UV-Vis spectra, and SEM. The photocatalytic activity was evaluated under natural solar light for decolorization and mineralization of azo dye Orange II solution. The results showed that Nb/TiO2- and Ta/TiO2-mixed oxides have higher activity than the untreated TiO2 under natural solar light. The maximum activity was observed for Nb/TiO2 sample (at mass ratio of 1 : 0.1), which is characterized by the smallest crystalline size (17.79 nm). Comparing with the untreated TiO2, the solar decolorization and mineralization rates improved by about 140% and 237%, respectively, and the band gap reduced to 2.80 eV. The results suggest that the crystal lattices of TiO2 powder are locally distorted by incorporating Nb5+ species into TiO2, forming a new band energy structure, which is responsible for the absorption in the visible region. Unlike Ta/TiO2, the Nb/TiO2-mixed oxides can prevent the grain size growth of the treated TiO2, which is important to achieve high solar photoactivity

    Solar photocatalytic degradation of 4-chlorophenol: Mechanism and kinetic modelling

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    The present study reports a mechanism and kinetic model of solar photocatalytic degradation of 4-chlorophenol (4-CP) and its intermediates based on the experimental results. Three intermediate compounds hydroquinone (HQ), 4-chlorocatechol (4cCat) and phenol were found during the solar degradation of different 4-CP concentrations using 0.5 g/L TiO2 as a photocatalyst. In order to obtain more details about the photocatalytic reaction pathway and the kinetic model, set of experiments were carried out using the major intermediates (HQ and 4cCat) as model reactants. To minimise the number of variables and give more accuracy to the kinetic model, the adsorption constants of 4-CPand its intermediates were obtained experimentally. The reaction mechanism for the photocatalytic degradation of 4-CP is proposed. The proposed model predicts well the concentrations of 4-CP and its by-products during the solar photocatalytic degradation at different initial concentrations. The model provides a very good fit of the experimental data and works for a wide range of 4-CP initial concentrations (25–100 mg/L)

    Enhancement of CO2 biofixation and lipid production by Chlorella vulgaris using coloured polypropylene film

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    Chlorella vulgaris was cultivated with light at different wavelengths (λmax) and irradiation intensities (I) by applying a coloured tape (CT) as a simple, inexpensive light filter. C. vulgaris was cultivated in a standard medium using blue (CTB), green (CTG), red (CTR), yellow (CTY) and white (CTW) CT to filter the light, as well the unfiltered light (U). The influence of λmax and I on specific growth rate (μ), nutrient removal efficiency (% RE of total nitrogen, TN, and phosphorus, TP), CO2 fixation rate (RC) and lipid productivity (Plipid) were evaluated. The highest biomass concentration Xmax of 2.26 g L−1 was measured for CTW with corresponding μ, TN and TP RE, RC and Plipid values of 0.95 d−1, 92% and 100%, 0.67 g L−1 d−1 and 83.6 mg L−1 d−1, respectively. The normalised μ and Plipid for U were significantly lower than in CTW of 33–50% and 75%, respectively. The corresponding non-normalised parameter values for CTB were significantly lower at 0.45 d−1, 0.18 g L−1, 15% and 37%, 0.03 g L−1 d−1 and 1.2 mg L−1 d−1. Results suggest a significant impact of I and λmax, with up to a 50% increase in growth and nutrient RE from optimising these parameters

    The cost benefit of algal technology for combined CO2 mitigation and nutrient abatement

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    The use of microalgae culture technology (MCT) for mitigating CO2 emissions from flue gases and nutrient discharges from wastewater whilst generating a biofuel product is considered with reference to the cost benefit offered. The review examines the most recent MCT literature (post 2010) focused on the algal biomass or biofuel production cost. The analysis reveals that, according to published studies, biofuel cost follows an approximate inverse relationship with algal or lipid productivity with a minimum production cost of $1 L−1 attained under representative conditions. A 35–86% cost reduction is reported across all studies from the combined harnessing of CO2 and nutrients from waste sources. This compares with 12–27% for obviating fertiliser procurement through using a wastewater nutrient source (or else recycling the liquor from the extracted algal biomass waste), and 19–39% for CO2 fixation from a flue gas feed. Notwithstanding the above, economic competitiveness with mineral fuels appears to be attainable only under circumstances which also feature: a) The inclusion of cost and environmental benefits from wastewater treatment (such as the energy and/or greenhouse gas emissions benefit from nutrient and CO2 discharge abatement), and/or a) Multiple installations over an extended geographic region where flue gas and wastewater sources are co-located

    Analysis of Heavy Metals in Selected Cigarettes and Syrupy Tobacco (Mu'assel) Brands Smoking in Baghdad Market Iraq

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    Smoking related diseases can be attributed to the inhalation of many different toxins including heavy metals which have a host of detrimental health effects. The current study reports the levels of cadmium (Cd) , Nickel (Ni), cupper(Cu), Iron(Fe), Zinc(Zn) and lead(Pb) in cigarettes and syrupy tobacco(Mu՝ assel)obtained from Baghdad – Iraq Markets.The mean concentrations of Cd,Ni,Cu,Fe,Zn and Pb were (26),(0.29),(0.42),(1000),(45.3)and (0.26) ppm  repectively .There were some differences in metal concentrations of cigarette brands producted by different manufacturers suggesting differences in the source of tobaccos used by different companies . For (Ni) , there were significant pairwis differences between Aspin and Al AMASE (Bountry) Mu՝ assel brands. For (Fe)AlAmase (Bountry)Brands had higher levels than Pine brands. Levels of (Cd) and (Pb) did not differ significantly across manufacturer group. Beacouse of the varity of toxic heavy metals in different brands of cigarette tobacco and their numerous negative health effects metal content in cigarette tobacco should be reduced. Keywords: Metal, Toxicity, Tobacco, smoking, Mu՝asse

    The Utilization of Algae and Seaweed Biomass for Bioremediation of Heavy Metal-Contaminated Wastewater

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    The presence of heavy metals in water bodies is linked to the increasing number of industries and populations. This has serious consequences for the quality of human health and the environment. In accordance with this issue, water and wastewater treatment technologies including ion exchange, chemical extraction, and hydrolysis should be conducted as a first water purification stage. However, the sequestration of these toxic substances tends to be expensive, especially for large scale treatment methods that require tedious control and have limited efficiency. Therefore, adsorption methods using adsorbents derived from biomass represent a promising alternative due to their great efficiency and abundance. Algal and seaweed biomass has appeared as a sustainable solution for environmentally friendly adsorbent production. This review further discusses recent developments in the use of algal and seaweed biomass as potential sorbent for heavy metal bioremediation. In addition, relevant aspects like metal toxicity, adsorption mechanism, and parameters affecting the completion of adsorption process are also highlighted. Overall, the critical conclusion drawn is that algae and seaweed biomass can be used to sustainably eliminate heavy metals from wastewater

    Evaluation of the level of Some Heavy Metals in Tobacco of Domestic and Imported Cigarette Brands Used in Iraq

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    Smoking-related diseases can be attributed to the inhalation of many different toxins, including heavy metals, which have a host of harmful health effects. The primary objective of this study was to determine whether local and imported cigarette brands used in Iraq , have they elevated levels of metals or not .Three metals Lead (Pb) , Cadmium (Cd) and Chromium(Cr) were determined in tobacco of seventeen brands of imported cigarettes commonly available in Iraq and three Iraqi domestic cigarettes , which were randomly taken from retail market in Baghdad by using flame atomic absorption spectrometry. The produced data of imported and local cigarette brands were discussed and compared together and with studies from elsewhere .The results obtained showed that mean concentrations of lead for all cigarette brands was 5.87 ?g/g dry weight (range 2.27-11,67 ?g/g) , cadmium 0.57?g/g dry weight (range 0.1-1.57 ?g/g) and chromium 3.77?g/g dry weight (range 0.0-11.21 ?g/g) ..There was a large variability in Pb, Cd and Cr content of samples of cigarettes. Pb concentration was the highest, followed by Cr while Cd was the lowest. The investigation confirmed that most of the Iraqi and imported cigarettes in Iraq are contaminated with Pb, Cd, and Cr and quantitatively their distribution is clearly above the safer limits of WHO

    Impact of CO2 concentration and ambient conditions on microalgal growth and nutrient removal from wastewater by a photobioreactor

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    The increase in atmospheric CO2 concentration and the release of nutrients from wastewater treatment plants (WWTPs) are environmental issues linked to several impacts on ecosystems. Numerous technologies have been employed to resolves these issues, nonetheless, the cost and sustainability are still a concern. Recently, the use of microalgae appears as a cost-effective and sustainable solution because they can effectively uptake CO2 and nutrients resulting in biomass production that can be processed into valuable products. In this study single (Spirulina platensis (SP.PL) and mixed indigenous microalgae (MIMA) strains were employed, over a 20-month period, for simultaneous removal of CO2 from flue gases and nutrient from wastewater under ambient conditions of solar irradiation and temperature. The study was performed at a pilot scale photo-bioreactor and the effect of feed CO2 gas concentration in the range (2.5–20%) on microalgae growth and biomass production, carbon dioxide bio-fixation rate, and the removal of nutrients and organic matters from wastewater was assessed. The MIMA culture performed significantly better than the monoculture, especially with respect to growth and CO2 bio-fixation, during the mild season; against this, the performance was comparable during the hot season. Optimum performance was observed at 10% CO2 feed gas concentration, though MIMA was more temperature and CO2 concentration sensitive. MIMA also provided greater removal of COD and nutrients (~83% and >99%) than SP.PL under all conditions studied. The high biomass productivities and carbon bio-fixation rates (0.796–0.950 gdw·L−1·d−1 and 0.542–1.075 gC·L−1·d−1 contribute to the economic sustainability of microalgae as CO2 removal process. Consideration of operational energy revealed that there is a significant energy benefit from cooling to sustain the highest productivities on the basis of operating energy alone, particularly if the indigenous culture is used
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