Use of X-ray Computed Microtomography to Measure the Leaching Behaviour of Metal Sulphide Ores

Heap leaching is an important hydrometallurgical method to extract valuable metals from ores, especially low grade ores. The main disadvantages of heap leaching are the long processing time and low extraction efficiencies. Currently, a major barrier in fully understanding the leaching process is the study of the mass transport and surface chemistry at individual ore particle and mineral grain scale. This thesis describes a combined experimental and modelling approach to visualise, quantify and predict the leach behaviour based on X-ray Computed Microtomography (XMT, or micro-CT). An automatic image processing package was developed to process the 3D volume data. Individual ore particles as well as individual mineral grains can be tracked using a centroid tracking algorithm and a novel fast tracking algorithm respectively. The systematic and random errors and uncertainties in the image volume measurements were quantified. It was found that both the systematic and random errors are a strong function of the grain size relative to the voxel size. The random error can be reduced by combining the results from either multiple scans of the same object or scans of multiple similar objects while the systematic error can be eliminated by using volume standards. The leach performance for a leaching column was quantified at different scales and it was found that the leach behaviour and its variability were difficult to quantify at large scales (column and individual ore particle scale), but can be quantified at mineral grain scale by using a novel statistical analysis method. The tracked grains were divided into different size-distance categories to analyse the average leach performance and the variation for each category. Both grain size and distance dependencies were observed. The size dependency is more dominant at the early stage of leaching whereas the distance dependency can significantly influence the ultimate recovery. A method for using the data to estimate the variability in the in-situ surface kinetics was also developed. A model for simulating the grain dissolution and the resultant kinetics based directly on XMT based 3D volume is introduced. The simulations were able to accurately predict both the overall leaching trends, as well as the leaching behaviour of mineral grains in classes based on their size and distance to the particle surface.Open Acces

Variational Autoencoders for Deforming 3D Mesh Models

3D geometric contents are becoming increasingly popular. In this paper, we study the problem of analyzing deforming 3D meshes using deep neural networks. Deforming 3D meshes are flexible to represent 3D animation sequences as well as collections of objects of the same category, allowing diverse shapes with large-scale non-linear deformations. We propose a novel framework which we call mesh variational autoencoders (mesh VAE), to explore the probabilistic latent space of 3D surfaces. The framework is easy to train, and requires very few training examples. We also propose an extended model which allows flexibly adjusting the significance of different latent variables by altering the prior distribution. Extensive experiments demonstrate that our general framework is able to learn a reasonable representation for a collection of deformable shapes, and produce competitive results for a variety of applications, including shape generation, shape interpolation, shape space embedding and shape exploration, outperforming state-of-the-art methods.Comment: CVPR 201

Characterizing Location-based Mobile Tracking in Mobile Ad Networks

Mobile apps nowadays are often packaged with third-party ad libraries to monetize user data

Philology, anthropology and poetry in Arthur Waley\u27s translation of the Shijing

The topic of my thesis is Arthur Waley and his translation of the Shijing, or The Book of Songs (1937), as Waley entitled it. The Book of Songs is especially noted for its philological ingenuity, anthropological insight and poetic appeal; during my preliminary research I discovered that there exists an interesting interplay between these three aspects of this translation. In this thesis, I hope to examine the textual and thematic hermeneutics of The Book of Songs. Waley did not read the Shijing as a scriptural text inscribed with sagely intention and authority; rather, he returned it to its folkloric origin, presenting the Shijing as an anthropological document of the lives of ancient Chinese people, an imaginative expression of the desires, beliefs and values of a primitive society, and a vivid mimesis of ancient life. Waley’s philological decisions were underpinned by this general interpretive orientation, informed by his understanding of the anthropological significance of the Shijing and guided by an attentive concern for poetic cohesion. The anthropological and poetic aspects were mutually implicated. The Book of Songs displays a keen interest in the common people, and Waley’s knowledge and insight in comparative anthropology enabled the Western reader to hear in this exotic text distant echoes from their own traditions. These anthropological underpinnings help to articulate and enrich the poetics of The Book of Songs. Waley’s overall design and the poetic language he employed bring forth these anthropological aspects in a poetic manner. The “folk” elements in the Shijing were foregrounded in The Book of Songs and deemed to be aesthetically interesting. The style and voice that Waley developed in his translation communicate the naive appeal of a folk aesthetic, and convey the compositional features and modes of experience of the “primitive” imagination. In Waley’s translation, the remote, difficult text of the Shijing is transformed into natural, evocative English poetry, and the philological, anthropological and poetic aspects of The Book of Songs coalesce into a Chinese aesthetic that is fresh and spontaneous, enjoying a pristine intimacy with Nature

New poetry and old Cathay : translational sinography in the early twentieth-century English literary world

This thesis looks into the culture of reading, translating, and publishing classical Chinese poetry in the English literary world between the 1890s and the 1920s. It explores the mediating and constructive roles of translation (broadly construed) in the formation of knowledge about Chinese literature by focusing on an unconventional segment of the field – poet-translators who integrate Chinese poetry with the pursuit of literary modernism, whose avid experimentalism and lack of sinological credentials run counter to the fidelity principle of translation. I try to foreground the dynamism of this literary contact zone by correlating three dimensions of networks: the transtextual modes in which translation and rewriting are performed – sinological translation, indirect (re)translation, collaborative translation, literary chinoiserie, aesthetic translation, imitative translation, and pseudotranslation; discursive networks in the intertextual field; and sociological networks of agents and institutions in the field of cultural production – publishers, reviewers, editors, patrons, professional societies, and literary circles. This triangulation approach accentuates the complexities of transcultural interchange and serves the larger goal of transcending the binarism of East/West and the sometimes reductive analytic model of text-versus-context. Examining peripheral modes of translation like indirect (re)translation, imitative translation, and pseudotranslation, I hope to broaden the historical landscape of translating Chinese literature and query normative categorizations in our critical vocabulary, and furthermore contribute to theoretical enquiries about the “translational” by probing into liminal cases. I consider translations as intertexts in discursive formations. Special attention is given to how intertexts from the archive of writing China in the West and from contemporaneous discursive formations are reconfigured in literary modernism’s transcultural imaginary. More specifically, I conceptualise translation and other kindred modes of rewriting as “sinographies” – forms of writing and discursive strategies that articulate the diverse meanings of China. For the poet-translators and sinographers discussed in this thesis, reading and translating China become an extended thought experiment through which larger cultural questions are thought over; they engage with the hypothetical Chinese poem in multiple, creative ways, inscribing different layers of meaning on the Chinese palimpsest. Their practices evince a heuristics of Chineseness, whereby knowledge about the self and the other becomes mutually constitutive and translation manifests its transformative power