Computational magnetohydrodynamics - Application

There are many processes, particularly in the nuclear and metals processing industries, where electromagnetic fields are used to influence the flow behaviour of a fluid. Procedures exploiting finite volume (FV) methods in both structured and unstructured meshes have recently been developed which enable this influence to be modelled in the context of conventional FV CFD codes. A range of problems have been tackled by the authors, including electromagnetic pumps and brakes, weirs and dams in steelmaking tundishes and interface effects in aluminium smelting cells. Two cases are presented here, which exemplify the application of the new procedures. The first case investigates the influence of electromagnetic fields on solidification front progression in a tin casting and the second case shows how the liquid metals free surface may be controlled through an externally imposed magnetic field in the semi-levitation casting process.

Genetic and phenotypic population divergence on a microgeographic scale in brown trout.

Salmonid populations of many rivers are rapidly declining. One possible explanation is that habitat fragmentation increases genetic drift and reduces the populations' potential to adapt to changing environmental conditions. We measured the genetic and eco-morphological diversity of brown trout (Salmo trutta) in a Swiss stream system, using multivariate statistics and Bayesian clustering. We found large genetic and phenotypic variation within only 40 km of stream length. Eighty-eight percent of all pairwise F(ST) comparisons and 50% of the population comparisons in body shape were significant. High success rates of population assignment tests confirmed the distinctiveness of populations in both genotype and phenotype. Spatial analysis revealed that divergence increased with waterway distance, the number of weirs, and stretches of poor habitat between sampling locations, but effects of isolation-by-distance and habitat fragmentation could not be fully disentangled. Stocking intensity varied between streams but did not appear to erode genetic diversity within populations. A lack of association between phenotypic and genetic divergence points to a role of local adaptation or phenotypically plastic responses to habitat heterogeneity. Indeed, body shape could be largely explained by topographic stream slope, and variation in overall phenotype matched the flow regimes of the respective habitats.

Second Welland Canal - Book 1, Survey Map 9 - Lock 2 in Grantham Township

Survey map of the Second Welland Canal created by the Welland Canal Company showing a portion of the Grantham Township sometimes referred to as the Welland Vale. Identified structures associated with the Canal include Lock 2, several weirs, and the Lock Tender's House. The surveyors' measurements and notes can be seen in red and black ink and pencil. Features of the First Welland Canal are noted in red ink and include the old towing path and the Old Canal itself. Local area landmarks and businesses are also identified and include streets and roads (ex. Side Line and Old Road to Port Dalhousie), J. C. Clark's Ice House, J. L. Ranney Store House, a burnt mill, barrel shed, a building leased to Michael Kerrins, and a number of unidentified structures (possibly houses or cabins) belonging to D. Cain, R. Cain, W. Weaver and W. Huddy. A New Road to St. Catharines is featured in red ink. Properties and property owners of note are: Concession 5 Lots 20, 21 and 22, Concession 6 Lots 20 and 21, Thomas Adams, John Gould, George Rykert, Theophilus Mack, William H. Merritt, J. L. Ranney, and the Board of Works.

Second Welland Canal - Book 2, Survey Map 2 - Locks 9 and 10 in Grantham

Survey map of the Second Welland Canal created by the Welland Canal Company showing the Grantham Township between the Town of St. Catharines and Merritton. Identified structures associated with the Canal include Locks 9 and 10, waste weirs, the towing path, a 2nd towing path, and the Canal waterway itself. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks are also identified and include roads (ex. Road to Centreville), hydraulic race, and the Centreville Mill. Properties and property owners of note are: Concession 8 Lots 12 and 12, Lewis Traver, Richard Ash, John Bradley, Owen Clifford, Orson Phelps, C. Bradley, the W. C. Loan Company, and T. Towers Mill Lot.

Second Welland Canal - Book 2, Survey Map 3 - Locks 8, 9 and 10 in Grantham

Survey map of the Second Welland Canal created by the Welland Canal Company showing the Grantham Township between the Town of St. Catharines and Merritton. Identified structures associated with the Canal include Locks 8, 9, and 10, waste weirs, the towing path, and several floating bridges. The surveyors' measurements and notes can be seen in red and black ink and pencil. Several stones and tree stumps likely used in the measurements are identified on the map. Local area landmarks are also identified and include streets and roads(ex. Macadamized Road to Thorold), J. Hamilton's Hotel, a school house, McCoy's Farm House, Bradley's House, O. Phelps Saw Mill, Disher and Hait's Woolen Mill, Centreville Mills, a bridge, several barns, and a number of structures (possibly houses, cabins, or shops) belonging to: P. McCoy, E. McLachlan, T. Wilson, W. Wilson, M. Bradley, S. Bradley, P. Boyle, J. Bradley, E. Grant, and W. Church. Lock 12 and 15 of the original canal are also identified. Properties and property owners of note are: Concession 8 Lots 12, 13 and 14, O. J. Phelps, P. McCoy, A. Bradley, C. Bradley, T. Reed, O. Clifford, J. Bradley, W. C. Loan Company, Duffin, and T. Towers Mill Lot.

Reading 'The Truman Show' inside out

This essay explores how The Truman Show, Peter Weir’s film about a television show, deserves more sustained analysis than it has received since its release in 1998. I will argue that The Truman Show problematizes the binary oppositions of cinema/television, disruption/stability, reality/simulation and outside/inside that structure it. The Truman Show proposes that binary oppositions such as outside/inside exist in a mutually implicating relationship. This deconstructionist strategy not only questions the film’s critical position, but also enables a reflection on the very status of film analysis itself.

Differential macrohabitat use by birds on an unregulated lowland floodplain of south-eastern Australia

In many lowland floodplains around the world, upriver interferences to flows (weirs, dams, off-takes) have led to much reduced frequency and duration of flooding. As a result, many floodplain wetlands are now inundated relatively rarely if at all. Given regulation of most lowland rivers in southeastern Australia, we assessed use of wetlands by birds in the essentially unregulated Ovens River in northeastern Victoria. Twelve sites (0.4-1.2 ha) were studied after flooding. Four sites were 'permanent billabongs', four were temporary wetlands and the other four were randomly selected woodland sites >60 m from the nearest water body (including the river) acting as 'control' or 'reference' sites. Aquatic birds were not recorded using woodland sites, but many species were differentially associated with either billabongs or temporary wetlands. A surprising number of non-aquatic birds either exclusively or differentially were associated with wetland sites compared with woodland sites. We concluded that heterogeneous macrohabitat will increase local avian biodiversity on lowland floodplains. Moreover, densities and diversity of non-aquatic, woodland species also increased with the presence of wetlands. Temporary wetlands were used differently from permanent billabongs by birds, especially in foraging methods. This suggests that the reinstatement of major flooding on heavily regulated floodplains would be ecologically advantageous for birds by providing foraging and breeding opportunities.

Fishways in Australia

In Australian regulated rivers, dams and weirs have contributed to serious declines in the distribution and abundance of migratory fish. This thesis has evaluated four fishways in Victoria, New South Wales and Queensland and provided new information for 51 migratory fish species. Fishways will be crucial for management and conservation of biodiversity.

A Ramsar wetland in crisis the Coorong, Lower Lakes and Murray Mouth, Australia

The state of global freshwater ecosystems is increasingly parlous with water resource development degrading high-conservation wetlands. Rehabilitation is challenging because necessary increases in environmental flows have concomitant social impacts, complicated because many rivers flow between jurisdictions or countries. Australia's MurrayDarling Basin is a large river basin with such problems encapsulated in the crisis of its Ramsar-listed terminal wetland, the Coorong, Lower Lakes and Murray Mouth. Prolonged drought and upstream diversion of water dropped water levels in the Lakes below sea level (20092010), exposing hazardous acid sulfate soils. Salinities increased dramatically (e.g. South Lagoon of Coorong>200gL-1, cf. modelled natural 80gL-1), reducing populations of waterbirds, fish, macroinvertebrates and littoral plants. Calcareous masses of estuarine tubeworms (Ficopomatus enigmaticus) killed freshwater turtles (Chelidae) and other fauna. Management primarily focussed on treating symptoms (e.g. acidification), rather than reduced flows, at considerable expense (≥AU$2 billion). We modelled a scenario that increased annual flows during low-flow periods from current levels up to one-third of what the natural flow would have been, potentially delivering substantial environmental benefits and avoiding future crises. Realisation of this outcome depends on increasing environmental flows and implementing sophisticated river management during dry periods, both highly contentious options.

Integrated modelling of cost-effective siting and operation of flow-control infrastructure for river ecosystem conservation

Wetland and floodplain ecosystems along many regulated rivers are highly stressed, primarily due to a lack of environmental flows of appropriate magnitude, frequency, duration, and timing to support ecological functions. In the absence of increased environmental flows, the ecological health of river ecosystems can be enhanced by the operation of existing and new flow-control infrastructure (weirs and regulators) to return more natural environmental flow regimes to specific areas. However, determining the optimal investment and operation strategies over time is a complex task due to several factors including the multiple environmental values attached to wetlands, spatial and temporal heterogeneity and dependencies, nonlinearity, and time-dependent decisions. This makes for a very large number of decision variables over a long planning horizon. The focus of this paper is the development of a nonlinear integer programming model that accommodates these complexities. The mathematical objective aims to return the natural flow regime of key components of river ecosystems in terms of flood timing, flood duration, and interflood period. We applied a 2-stage recursive heuristic using tabu search to solve the model and tested it on the entire South Australian River Murray floodplain. We conclude that modern meta-heuristics can be used to solve the very complex nonlinear problems with spatial and temporal dependencies typical of environmental flow allocation in regulated river ecosystems. The model has been used to inform the investment in, and operation of, flow-control infrastructure in the South Australian River Murray.

Stone soup installation

This installation work sets out a number of proposals for future collaborations with the Southwest Victoria regions communities. Through a series of drawings/ diagram that focus on particular aspects of the region: stone walls, eel weirs. The concept for the work is taken from the folktale of travelers who come to a village asking for food and when denied, they make a magical stone soup which only need a few garnishes. in the end the traveler have enough soup for the entire village. this stands as a allegory of the way artist engage with community and induce cooperative activities a through the trickery of art practices by which all can partake and produce common, mutually beneficial experience.

Constraints upon the response of fish and crayfish to environmental flow releases in a regulated headwater stream network

In dry climate zones, headwater streams are often regulated for water extraction causing intermittency in perennial streams and prolonged drying in intermittent streams. Regulation thereby reduces aquatic habitat downstream of weirs that also form barriers to migration by stream fauna. Environmental flow releases may restore streamflow in rivers, but are rarely applied to headwaters. We sampled fish and crayfish in four regulated headwater streams before and after the release of summer-autumn environmental flows, and in four nearby unregulated streams, to determine whether their abundances increased in response to flow releases. Historical data of fish and crayfish occurrence spanning a 30 year period was compared with contemporary data (electrofishing surveys, Victoria Range, Australia; summer 2008 to summer 2010) to assess the longer-term effects of regulation and drought. Although fish were recorded in regulated streams before 1996, they were not recorded in the present study upstream or downstream of weirs despite recent flow releases. Crayfish (Geocharax sp. nov. 1) remained in the regulated streams throughout the study, but did not become more abundant in response to flow releases. In contrast, native fish (Gadopsis marmoratus, Galaxias oliros, Galaxias maculatus) and crayfish remained present in unregulated streams, despite prolonged drought conditions during 2006-2010, and the assemblages of each of these streams remained essentially unchanged over the 30 year period. Flow release volumes may have been too small or have operated for an insufficient time to allow fish to recolonise regulated streams. Barriers to dispersal may also be preventing recolonisation. Indefinite continuation of annual flow releases, that prevent the unnatural cessation of flow caused by weirs, may eventually facilitate upstream movement of fish and crayfish in regulated channels; but other human-made dispersal barriers downstream need to be identified and ameliorated, to allow native fish to fulfil their life cycles in these headwater streams.

Real-Time Control Of Floods Along The Demer River, Belgium, By Means Of MPC In Combination With GA And A Fast Conceptual River Model

Climate model projections show that climate change will further increase the risk of flooding in many regions of the world. There is a need for climate adaptation, but building new infrastructure or additional retention basins has its limits, especially in densely populated areas where open spaces are limited. Another solution is the more efficient use of the existing infrastructure. This research investigates a method for real-time flood control by means of existing gated weirs and retention basins. The method was tested for the specific study area of the Demer basin in Belgium but is generally applicable. Today, retention basins along the Demer River are controlled by means of adjustable gated weirs based on fixed logic rules. However, because of the high complexity of the system, only suboptimal results are achieved by these rules. By making use of precipitation forecasts and combined hydrological-hydraulic river models, the state of the river network can be predicted. To fasten the calculation speed, a conceptual river model was used. The conceptual model was combined with a Model Predictive Control (MPC) algorithm and a Genetic Algorithm (GA). The MPC algorithm predicts the state of the river network depending on the positions of the adjustable weirs in the basin. The GA generates these positions in a semi-random way. Cost functions, based on water levels, were introduced to evaluate the efficiency of each generation, based on flood damage minimization. In the final phase of this research the influence of the most important MPC and GA parameters was investigated by means of a sensitivity study. The results show that the MPC-GA algorithm manages to reduce the total flood volume during the historical event of September 1998 by 46% in comparison with the current regulation. Based on the MPC-GA results, some recommendations could be formulated to improve the logic rules.

Numerical Simulation Of Sediment Transport And Bedmorphology Around A Hydraulic Structure On A River

Scour around hydraulic structures is a critical problem in hydraulic engineering. Under prediction of scour depth may lead to costly failures of the structure, while over prediction might result in unnecessary costs. Unfortunately, up-to-date empirical scour prediction formulas are based on laboratory experiments that are not always able to reproduce field conditions due to complicated geometry of rivers and temporal and spatial scales of a physical model. However, computational fluid dynamics (CFD) tools can perform using real field dimensions and operating conditions to predict sediment scour around hydraulic structures. In Korea, after completing the Four Major Rivers Restoration Project, several new weirs have been built across Han, Nakdong, Geum and Yeongsan Rivers. Consequently, sediment deposition and bed erosion around such structures have became a major issue in these four rivers. In this study, an application of an open source CFD software package, the TELEMAC-MASCARET, to simulate sediment transport and bed morphology around Gangjeong weir, which is the largest multipurpose weir built on Nakdong River. A real bathymetry of the river and a geometry of the weir have been implemented into the numerical model. The numerical simulation is carried out with a real hydrograph at the upstream boundary. The bedmorphology obtained from the numerical results has been validated against field observation data, and a maximum of simulated scour depth is compared with the results obtained by empirical formulas of Hoffmans. Agreement between numerical computations, observed data and empirical formulas is judged to be satisfactory on all major comparisons. The outcome of this study does not only point out the locations where deposition and erosion might take place depending on the weir gate operation, but also analyzes the mechanism of formation and evolution of scour holes after the weir gates.

Trabalho, pobreza e caridade: as ações do Padre Ibiapina nos sertões do Nordeste

This work started from an investigation concerning the process of education, moralization and disciplining of the poor in the backlands of the Brazilian Northeast region, in the second half of the 19th century, through the incorporation of the values of productive work. In order to do so, we took as our field of investigation the missions of Father José Antônio Pereira Ibiapina (1806-1883), in which an extensive work was developed, including the construction of twenty two (22) charity houses in the States of Rio Grande do Norte, Paraíba, Pernambuco, Ceará e Piauí, but also of weirs, churches, graveyards, hospitals and so forth. Given the socio-historical character of the research, we adopted qualitative methods of analysis and the following procedures: survey and analysis of documents, statute and internal rules that ordered the workings of the charity houses; biographies on Father Ibiapina and the missions‟ reports, as well as various sorts of publications on the missionary. Our study comprises his 27 year-period of missionary-religious activity (1856-1883), and undertakes an analysis on the topic of poverty, since the medieval Christian take on it until modernity, when it stops representing a value and becomes a problem to be solved through work. The socio-political context in which Ibiapina lived in the Northeast was marked by the consequence of droughts and economic crises in the region. The analysis of the documents indicates that, in the circumstances of political weakness and lack of interest for regional demands by the national political agenda, his missionary actions produced strong effects. Starting from an ethics of valorization of work, which combined modern and traditional elements, his actions set up disciplinary, moralizing and civil educational practices of the poor, founding, simultaneously, a pragmatic religious experience directed at the resolution of the problems caused by poverty. In that sense, we observe that such actions are connected to the broader process of moralization and education of the poor, but the analysis also suggests that their inscription into the social order articulated both forward as well as conservative aspects of the established system