665 research outputs found

    High-pressure x-ray diffraction study of bulk and nanocrystalline PbMoO4

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    We studied the effects of high-pressure on the crystalline structure of bulk and nanocrystalline scheelite-type PbMoO4. We found that in both cases the compressibility of the materials is highly non-isotropic, being the c-axis the most compressible one. We also observed that the volume compressibility of nanocrystals becomes higher that the bulk one at 5 GPa. In addition, at 10.7(8) GPa we observed the onset of an structural phase transition in bulk PbMoO4. The high-pressure phase has a monoclinic structure similar to M-fergusonite. The transition is reversible and not volume change is detected between the low- and high-pressure phases. No additional structural changes or evidence of decomposition are found up to 21.1 GPa. In contrast nanocrystalline PbMoO4 remains in the scheelite structure at least up to 16.1 GPa. Finally, the equation of state for bulk and nanocrystalline PbMoO4 are also determined.Comment: 18 pages, 4 figure

    Polymer Composites in Green Technology: A Review

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    Rapid depletion of fossil resources, high demand for energy and global warming together encourage us to look for renewable polymer items with low carbon. ‘Green monomers’ could be derived from bio-refineries, biowastes or renewable oil, plastics-waste. The polymer obtained from such green monomers are renewable and can display good characteristics equivalent to the traditional polymers or sometimes better than the existing polymers. Green technology is a global movement to create vibrant and sustainable cities. Green technology addresses social, economic and environmental values and creates a green economy. Green technology is based on the process of using waste materials for beneficial purposes by managing, and recycling the waste. This technology involves the waste treatment, incineration and management. Many materials prepared form green composites are cost effective in-terms less consumption of electricity, and water, at the same time a significant decrease in CO2 emission, and solid waste generation. The present review presents the effective techniques, difficulties, applications & information on bio-polymers, natural fiber reinforcements, properties of the different green composites and recommendations

    An assessment of the component-based view for metaheuristic research.

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    Masters Degree. University of KwaZulu-Natal, Durban.Several authors have recently pointed to a crisis within the metaheuristic research field, particularly the proliferation of metaphor-inspired metaheuristics. Common problems identified include using non-standard terminology, poor experimental practices, and, most importantly, the introduction of purportedly new algorithms that are only superficially different from existing ones. These issues make similarity and performance analysis, classification, and metaheuristic generation difficult for both practitioners and researchers. A component-based view of metaheuristics has recently been promoted to deal with these problems. A component based view argues that metaheuristics are best understood in terms of their constituents or components. This dissertation presents three papers that are thematically centred on this view. The central problem for the component-based view is the identification of components of a metaheuristic. The first paper proposes the use of taxonomies to guide the identification of metaheuristic components. We developed a general and rigorous method, TAXONOG-IMC, that takes as input an appropriate taxonomy and guides the user to identify components. The method is described in detail, an example application of the method is given, and an analysis of its usefulness is provided. The analysis shows that the method is effective and provides insights that are not possible without the proper identification of the components. The second paper argues for formal, mathematically sound representations of metaheuristics. It introduces and defends a formal representation that leverages the component based view. The third paper demonstrates that a representation technique based on a component based view is able to provide the basis for a similarity measure. This paper presents a method of measuring similarity between two metaheuristic-algorithms, based on their representations as signal flow diagrams. Our findings indicate that the component based view of metaheuristics provides valuable insights and allows for more robust analysis, classification and comparison

    Exploring the role of the built environment in redefining Durban’s water culture: a proposed recreation hub and Maritime museum for Durban harbour.

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    Master’s Degree. University of KwaZulu-Natal, Durban.Water controls life on earth as a natural asset. This is just as applicable within the urban setting. An element which is equally enabling as it is incapacitating, water is constantly shaping the way we experience life on earth. The successful operating of the urban environment depends fundamentally on the efficient movement of water into and out of the city. While in urban settings, water is often concealed and controlled to create the illusion of a hydrophobic space, the hidden waterways which run below the surface of cities are proof that water is still a part of our everyday lives. The relationship between architecture and water is constantly evolving, and the design of modern cities does not always cater to the integrity of water and its natural sources. The dichotomous relationship between architecture and nature further reinforces this disassociation of people water and architecture. This document aims to explore how architecture can adapt and transform to enable a better water culture within cities, so as to protect natural sources and ensure a more resilient city

    Real Time GAZED: Online Shot Selection and Editing of Virtual Cameras from Wide-Angle Monocular Video Recordings

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    Eliminating time-consuming post-production processes and delivering high-quality videos in today's fast-paced digital landscape are the key advantages of real-time approaches. To address these needs, we present Real Time GAZED: a real-time adaptation of the GAZED framework integrated with CineFilter, a novel real-time camera trajectory stabilization approach. It enables users to create professionally edited videos in real-time. Comparative evaluations against baseline methods, including the non-real-time GAZED, demonstrate that Real Time GAZED achieves similar editing results, ensuring high-quality video output. Furthermore, a user study confirms the aesthetic quality of the video edits produced by the Real Time GAZED approach. With these advancements in real-time camera trajectory optimization and video editing presented, the demand for immediate and dynamic content creation in industries such as live broadcasting, sports coverage, news reporting, and social media content creation can be met more efficiently

    High-pressure structural investigation of several zircon-type orthovanadates

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    Room temperature angle-dispersive x-ray diffraction measurements on zircon-type EuVO4, LuVO4, and ScVO4 were performed up to 27 GPa. In the three compounds we found evidence of a pressure-induced structural phase transformation from zircon to a scheelite-type structure. The onset of the transition is near 8 GPa, but the transition is sluggish and the low- and high-pressure phases coexist in a pressure range of about 10 GPa. In EuVO4 and LuVO4 a second transition to a M-fergusonite-type phase was found near 21 GPa. The equations of state for the zircon and scheelite phases are also determined. Among the three studied compounds, we found that ScVO4 is less compressible than EuVO4 and LuVO4, being the most incompressible orthovanadate studied to date. The sequence of structural transitions and compressibilities are discussed in comparison with other zircon-type oxides.Comment: 34 pages, 2 Tables, 11 Figure

    Anticoagulant property of sulphated polysaccharides extracted from marine brown algae collected from Mandapam Island, India

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    The marine brown algae: Sargassum tenerrimum, Sargassum wightii, Turbinaria conoides, Turbinaria ornata and Padina tetrastromatica were collected from Mandapam Island, India. The crude sulphated polysaccharides (SPS) were extracted using hot water and examined for anticoagulation activity. The sugar, sulphate and protein in crude SPS were analyzed. The presence of sulphated polysaccharide was confirmed by agarose gel electrophoresis and further characterized by Fourier transform infrared spectroscopy (FTIR). The FTIR analysis of crude SPS showed characteristic band of polysaccharides at 900, 1740 cm-1 and ester sulphate at 1250 to 1260 cm-1. Moreover, the absorbance band at 820 cm-1 for S. tenerrimum, S. wightii, T. conoides and T. ornata denotes sulphation at equatorial position, but in the case of P. tetrastromatica, sulphation at axial position is denoted by absorbance band at 850 cm-1. The heparin like activity of crude SPS was determined by metachromatic assay. The anticoagulant activity of crude SPS was evaluated by activated partial thromboplastin time (APTT) and prothrombin time (PT) assays. The metachromatic, APTT and heparinoid activities of crude SPS from S. tenerrimum, S. wightii, T. conoides, T. ornata and P. tetrastromatica were in the range of 0.045 to 0.0347, 134 to 89 s and 25.47 to 14.5 USP units/mg, respectively. The prolongation of prothrombin time by crude SPS was not found.Keywords: Brown algae, sulphated polysaccharides, Fourier transform infrared spectrometer (FTIR), agarose gel, metachromatic activity, activated partial thromboplastin time (APTT), heparinAfrican Journal of Biotechnology Vol. 12(16), pp. 1937-194

    OPPRESSION, MARGINALISATION AND EDUCATION IN KERALA: IN DIALOGUE WITH FREIRE

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    The primary aim of this research is to develop my own critical perspective on oppression, marginalisation and education in Kerala, India. First, it critiques Freire’s educational thoughts including banking and problem-posing education; second, it goes on to extend Freire’s ideas to develop a dialogical methodology in the field of Education while addressing my fieldwork struggles and dialogues. Third, it addresses how Freire’s educational thoughts can also be critically understood to explore the oppressive and marginalizing nature of non-formal education and community work in Kerala; fourth, this thesis contributes to innovative knowledge mainly at theoretical, methodological and empirical levels
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