Search results

The purpose of this paper is to present a novel computational framework based on the lattice Boltzmann method (LBM) and discrete element method (DEM) capable of simulating fines migration in three dimensions. Fines migration occurs in a block cave mine, and is characterised by the faster movement of fine and often low‐grade material towards the draw point in comparison to larger, blocky material.

This study builds on the foundations and applications outlined in a companion paper, in which the non‐Newtonian LBM‐DEM framework is defined and applied in 2D simulations. Issues relevant to the extension to 3D, such as spatial discretisation, fluid boundary conditions and the definition of synthetic bulk material parameters using a power law model, are discussed.

The results of the 3D DEM percolation replication showed that migration is predominantly limited to within the draw zone, and that the use of a low‐cohesion material model resulted in a greater amount of fines migration. The draw sensitivity investigation undertaken with the two bell partial block cave analysis did not show a significant difference in the amount of migration, despite the two draw strategies being deliberately chosen to result in isolated and interactive draw of material.

Along with the companion paper, this paper presents a novel application of the developed non‐Newtonian LBM‐DEM framework in the investigation of fines migration, which until now has been limited to scale models, cellular automata or pure DEM simulations. The results highlight the potential for this approach to be applied in an industrial context, and indicate a number of potential avenues for further research.

The purpose of this paper is to present a novel computational framework capable of simulating the block cave phenomenon of fines migration in two dimensions. Fines migration is characterised by the faster movement of fine and often low‐grade material towards the draw point in comparison to larger, blocky material. A greater understanding of the kinematic behaviour of fines and ore within the cave during draw is integral to the solution of this problem.

The lattice Boltzmann method (LBM) is employed in a nonlinear form to represent the fines as a continuum, and it is coupled to the discrete element method (DEM) which is used to represent large blocks. The issues relevant to this approach, such as fluid‐solid interaction, the synchronisation of explicit schemes, and the characterisation of a bulk material as a non‐Newtonian fluid are discussed.

Results of the 2D simulations reveal migration trends for the geometries, material properties and operational sequences analysed. By executing an extensive programme of numerical experiments the influence of these and other relevant block cave factors on the migration of fines could be isolated.

To the authors' knowledge, this is the first time the LBM has been used to simulate the flow of bulk materials. The non‐Newtonian LBM‐DEM framework is also a novel approach to the investigation of fines migration, which until now has been limited to scale models, cellular automata or pure DEM simulations. The results of the 2D migration analyses highlight the potential for this novel approach to be applied in an industrial context and also encourage the extension of the framework to 3D.

The purpose of this research is to highlight issues relating to binder migration in traditional lime mortars and the potential consequences of this phenomenon. The paper focuses on traditional mass masonry construction and will be of special interest to those surveying, maintaining and repairing historic ruinous structures and heavily exposed masonry bridges.

The paper draws on literature pertaining to the repair of traditional mass masonry structures and the somewhat limited science of binder dissolution and migration in saturated conditions. The paper also draws on the author's practical and academic knowledge of writing specifications for the repair of mass masonry structures and utilises examples of binder migration from several case study buildings.

The degree to which binder migration in traditional mortars occurs is little understood. It is, however, evident that migration of the binder occurs when saturated conditions are present and is exacerbated by prolonged moisture ingress. The effect of binder migration on the stability and performance of mass masonry structures is also little understood and requires greater attention. In addition, the nature of the repair mortars specified and the degree to which these materials have set will have a bearing on the potential for binder migration.

An assessment of binder migration in traditional lime mortars and its effect on the stability and performance of mass masonry structures has never previously been undertaken. This paper is the first to highlight the problem.

This case study aims to demonstrate that in-house integrated library systems migration can be accomplished by a dedicated team of librarians without advanced tools or prior experience with data migration or systems integration.

This migration was accomplished by academic librarians using freely available tools: OpenOffice Calc, MarcEdit and the Koha Integrated Library System.

The data migration pathway presented here was developed and successfully used to transfer over 48,000 records in less than two months.

This case study presents an original process that is particularly effective for smaller libraries.

While similar case studies exist, most employ expensive third-party contractors for data migration or rely heavily on institutional IT departments.

The paper aims to explore the circumstances and processes involved in implementing and migrating from a proprietary integrated library system (ILS) (Follett’s Destiny) to an open-source ILS (Koha) for a special focus institution.

In 2012, the campus libraries of God’s Bible College (GBC) migrated to Koha. After locally hosting and supporting Koha for three years, GBC contracted a vendor (ByWater Solutions) to provide hosting and support, beginning in the fall of 2015.

The paper offers experiences and practical recommendations in migration and implementation. The paper will demonstrate that libraries, including special-focus institutions, can migrate efficiently and without vendor support. Additionally, the paper examines some of the reasons why libraries might consider vendor hosting and support.

The paper gives libraries a framework, illustrated with a special-focus institution case study, for selecting and migrating from a proprietary ILS to an open-source ILS. Such information will be of assistance in clarifying the process of migration and implementation for institutions seeking to move from a proprietary system, especially Destiny, to an open-source ILS.

The paper covers the steps taken to successfully migrate the database and offers a series of best practices for the adoption and migration process of an open-source ILS, providing librarians and other key stakeholders both theoretical and practical information in the selection and implementation of an open-source ILS.

This article addresses contemporary presentations of migrants, particularly women, as dependents and a ‘burden’ on welfare. Focusing mainly on Britain, it shows that, while immigration policies increasingly restrict their access to official welfare, migrants are crucial to the provision of welfare both to their own family and community and in mainstream services, including professional roles as well as in informal employment. Migrants are involved in complex networks of caring relations, often across national boundaries, in which they may provide care to others in order to provide for dependents back home.

The high value that Japanese place upon college prestige suggests that Japanese families will do whatever it takes to gain entry into the nation’s top colleges, including paying the high costs of preparation, tuition, or relocation. Of all the costs confronting parents of college-bound students, the greatest is that of migration, or the cost of attending college away from home. I use a 1995 cross-sectional dataset to examine how the pursuit of college quality factors into migration decisions among college students in Japan. My findings clearly show that the difference in university resources across regions is an important factor in determining migration decisions, while financial considerations are secondary.

Around 15% savings on freight costs, speedier packaging and elimination of dust contamination are claimed as a result of switching to Flo‐Pak free‐flow cushioning material as a case infiller for their export packs, according to Croda Inks Ltd, of Colliers Wood, London. The company previously used traditional wood wool to protect tins of printing ink, packed in cases made up for export. This early method promoted dust problems for the packers who were supplied with protective face masks. It also contributed to high costs of maintaining cleanliness within the works and made it necessary to operate a vigilant control system to cope with fine dust migration, which inexplicably all too often found its way inside the tin containers to contaminate the ink contents. Flo‐Pak became the simple solution to these acute problems.

The purpose of this paper is to explore the contextual determinants of transition from expatriation to migration (TEM) among ministers of religion originating from the developing world.

The authors used in-depth analysis of narratives of four African religious ministers working in France, plus interviews with their five superiors and three host country national colleagues.

The findings point to personal-level, organisational-level and country-level contextual determinants, which come into play as levers or barriers in the “TEM” process.

The study identifies a new category of global mobility research at the intersection of expatriation and migration and develops a theoretical framework which points to the positive and negative influence of three-layered contextual determinants on how expatriated low-status church ministers from the developing world become migrants. The authors found a so far unreported determinant of the personal context: the role of a world view: very visible as “God centrality” in the participants. Results also shed new light on the international careers of this overlooked category of “non-traditional expatriates” from Africa.

Confronting the unveiled sophisticated structural and physical characteristics of permanent magnets, notably the samarium–cobalt (Sm-Co) alloy, This work aims to introduce a simulation scheme that can link physics-based micromagnetics on the nanostructures and magnetostatic homogenization on the mesoscale polycrystalline structures.

The simulation scheme is arranged in a multiscale fashion. The magnetization behaviors on the nanostructures examined with various orientations are surrogated as the micromagnetic-informed hysterons. The hysteresis behavior of the mesoscale polycrystalline structures with micromagnetic-informed hysterons is then evaluated by computational magnetostatic homogenization.

The micromagnetic-informed hysterons can emulate the magnetization reversal of the parameterized Sm-Co nanostructures as the local hysteresis behavior on the mesostructures. The simulation results of the mesoscale polycrystal demonstrate that the demagnetization process starts from the grain with the largest orientation angle (a) and then propagates to the surrounding grains.

The presented scheme depicts the demand for integrating data-driven methods, as the parameters of the surrogate hysteron intrinsically depend on the nanostructure and its orientation. Further hysteron parameters that help the surrogate hysteron emulate the micromagnetic-simulated magnetization reversal should be examined.

This work provides a novel multiscale scheme for simulating the polycrystalline permanent magnets’ hysteresis while recapitulating the nanoscale mechanisms, such as the nucleation of domains, and domain wall migration and pinning. This scheme can be further extended to simulate the part-level hysteresis considering the mesoscale features.