| 1. |
- Sumaila, U. Rashid, et al.
(författare)
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WTO must ban harmful fisheries subsidies
- 2021
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 374:6567, s. 544-544
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Das, A., et al.
(författare)
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Surface chemical and adsorption studies using Thiobacillus ferrooxidans with reference to bacterial adhesion to sulfide minerals
- 1999
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Ingår i: Biohydrometallurgy and the Environment toward the Mining of the 21st century. - : Elsevier. - 0444501932 ; , s. 697-707
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Konferensbidrag (refereegranskat)abstract
- Adhesion of Thiobacillus ferrooxidans to pyrite and chalcopyrite in relation to its importance in bioleaching and bioflotation has been studied. Electrokinetic studies as well as FT-IR spectra suggest that the surface chemistry of Thiobacillus ferrooxidans depends on bacterial growth conditions. Sulfur-,Pyrite- and chalcopyrite-grown Thiobacillus ferrooxidans were found to be relatively more hydrophobic. The altered surface chemistry of Thiobacillus ferrooxidans was due to secretion of newer and specific proteinaceous compounds. The adsorption density corresponds to a monolayer coverage in a horizontal orientation of the cells. The xanthate flotation of pyrite in presence of Thiobacillus ferrooxidans is strongly depressed where as the cells have insignificant effect on chalcopyrite flotation. This study demonstrate that:(a)Thiobacillus ferrooxidans cells can be used for selective flotation of chalcopyrite from pyrite and importantly at natural pH values.(b)Sulfur-grown cells exhibits higher leaching kinetics than ferrous ion-grown cells.
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| 3. |
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| 4. |
- P.K., Sharma, et al.
(författare)
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Surface characterization of Acidithiobacillus ferrooxidans cells grown under different conditions
- 2003
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Ingår i: Hydrometallurgy. - 0304-386X .- 1879-1158. ; 71:1-2, s. 285-292
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Tidskriftsartikel (refereegranskat)abstract
- The growth characteristics of a strain of Acidithiobacillus ferrooxidans isolated from mine water with ferrous ion, sulfur, or pyrite mineral as sole source of energy have been established. The electrokinetic behaviour of the bacterial cells was investigated and the cell surface groups were characterized by diffuse reflectance FT-IR and FT-Raman spectroscopies. The surface charge on the iron-grown cells (i.e.p., pH 2.0) is different from that on the solid-substrate-grown cells (i.e.p., pH 3.0-3.5) and the surface charge depends on the growth history of the bacteria. The FT-IR and FT-Raman spectra revealed a higher amount of protein content on the surface of the sulfur- and pyrite-grown cells compared to the iron-grown cells. These results suggest that the altered surface charge on the cells is due to differences in the protein content synthesized by bacteria exposed to different growth conditions.
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| 5. |
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| 6. |
- Sharma, P.K., et al.
(författare)
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Thiobacillus ferrooxidans interaction with sulfide minerals and selective chalcopyrite flotation from pyrite
- 1999
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Ingår i: Advances in flotation technology. - : Society for Mining, Metalurgy and Exploration. - 0873351843 ; , s. 147-165
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Konferensbidrag (refereegranskat)abstract
- The acidophilic and chemolithotrophic Thiobacillus ferrooxidans bacteria grown in the presence of soluble ferrous ions and solid substrates (sulfur, pyrite and chalcopyrite) as their energy source have been used in the investigations. The cell surfaces are characterized by zeta-potential, contact angle, FT-IR and FT-Raman studies. The adsorption isotherms of the cells on pyrite and chalcopyrite indicate that the adsorption begins on pyrite at a much lower equilibrium cell population than on chalcopyrite. The isotherms tend to level off at a cell adsorption density corresponding to a horizontal monolayer coverage when the geometrical dimensions of the cells are considered. In the presence of cells, the xanthate flotation of pyrite completely depressed, whereas chalcopyrite flotation is unaffected. The results suggest that chalcopyrite can be selectively floated from pyrite, also at a neutral pH region, in the presence of T. ferrooxidans cells
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| 7. |
- Yoganandam, K., et al.
(författare)
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Quasi-static puncture shear loading behaviour MWCNT/glass fibre epoxy laminates with various indenters
- 2023
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Ingår i: Polymer testing. - : Elsevier Ltd. - 0142-9418 .- 1873-2348. ; 127
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Tidskriftsartikel (refereegranskat)abstract
- Investigation was performed to evaluate the puncture resistance of multi-walled carbon nanotubes (MWCNTs)/glass fibre epoxy laminate composites using different indenters (conical, elliptical, flat, and hemispherical). For the puncture tests, MWCNT weight percentage and indenter type were varied. Furthermore, the impact of MWCNT on tensile, flexural, and interlaminar shear strength was evaluated. Ultrasonic C-scan provided insights into the damage evolution and failure mechanisms of the laminates under puncture. The results indicate that the flat indenter exhibits prolonged indentation time and enhanced energy absorption, resulting in a disc-shaped failure pattern. On the other hand, the conical indenter demonstrates rapid penetration due to its smaller contact surface area. The elliptical indenter generates higher frictional energy, leading to bulging damage. The hemispherical indenter showed an even distribution of force across the impacted surface, minimizing force concentration and reducing the extent of damage. These findings shed light on the puncture mechanisms of MWCNT/Glass fibre epoxy laminate composites, paving the way for more precise glass fibre laminate composite design and optimisation in practical applications such as aerospace, automotive, and sporting goods, where puncture loading is a critical consideration.
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| 8. |
- Ahsan, Amimul, et al.
(författare)
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Modeling the impacts of best management practices (BMPs) on pollution reduction in the Yarra River catchment, Australia
- 2023
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Ingår i: Applied water science. - : Springer. - 2190-5487 .- 2190-5495. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Pollution of a watershed by different land uses and agricultural practices is becoming a major challenging factor that results in deterioration of water quality affecting human health and ecosystems. Sustainable use of available water resources warrants reduction of Non-Point Source (NPS) pollutants from receiving water bodies through best management practices (BMPs). A hydrologic model such as the Soil and Water Assessment Tool (SWAT) can be used for analyzing the impacts of various BMPs and implementing of different management plans for water quality improvement, which will help decision makers to determine the best combination of BMPs to maximize benefits. The objective of this study is to assess the potential reductions of sediments and nutrient loads by utilizing different BMPs on the Yarra River watershed using the SWAT model. The watershed is subdivided into 51 sub-watersheds where seven different BMPs were implemented. A SWAT model was developed and calibrated against a baseline period of 1998–2008. For calibration and validation of the model simulations for both the monthly and annual nutrients and sediments were assessed by using the Nash–Sutcliffe efficiency (NSE) statistical index. The values of the NSE were found more than 0.50 which indicates satisfactory model predictions. By utilizing different BMPs, the highest pollution reduction with minimal costs can be done by 32% targeted mixed-crop area. Furthermore, the combined effect of five BMPs imparts most sediments and nutrient reductions in the watershed. Overall, the selection of a BMP or combinations of BMPs should be set based on the goals set in a BMP application project.
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| 9. |
- Bakshi, S. Das, et al.
(författare)
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Dry rolling/sliding wear of nanostructured bainite
- 2014
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 316:1-2, s. 70-78
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Tidskriftsartikel (refereegranskat)abstract
- The abrasive wear of carbide-free bainitic steel under dry rolling/sliding conditions has been studied. It is demonstrated that this nanostructure, generated by isothermal transformation at 200 °C, has a resistance to wear that supersedes that of other carbide-free bainitic steels transformed at higher temperatures. The experimental results, in combination with a theoretical analysis of rolling/sliding indicates that under the conditions studied, the role of sliding is minimal, so that the maximum shear stresses during contact are generated below the contact surface. Thus, the hardness following testing is found to reach a maximum below the contact surface. The fine scale and associated strength of the structure combats wear during the running-in period, but the volume fraction, stability and morphology of retained austenite plays a significant role during wear, by work-hardening the surface through phase transformation into very hard martensite
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| 10. |
- Bakshi, S. Das, et al.
(författare)
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Dry rolling/sliding wear of nanostructured pearlite
- 2015
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Ingår i: Materials Science and Technology. - 0267-0836 .- 1743-2847. ; 31:14, s. 1735-1744
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Tidskriftsartikel (refereegranskat)abstract
- The dry rolling-sliding wear behaviour of pearlite that has an interlamellar spacing of just 85 nm has been characterised. Its wear resistance is found to be comparable to that of much harder bainitic steels. Microstructural observations indicate that there is substantial plastic deformation of both ferrite and cementite components of pearlite in the vicinity of the wear surface. Plasticity is not expected from Hertzian analysis that assumes a smooth contact surface. Instead, it is likely to be a consequence of exaggerated stresses due to surface roughness. The material remains ductile to shear strains in the order of 4. Diffraction data indicate that the coherent domain size is reduced to about half the interlamellar spacing and that some of the cementite may dissolve and contribute to the expansion of the lattice parameter of ferrite
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