Sherritt (Canada)

The article examines the Chinese science fiction blockbuster The Wandering Earth by looking at three levels of (im)mobility: from the planet’s surface to the subsurface, above the surface, and the planet itself. It argues that mobility and immobility in the film always go hand in hand, and that the mobility of one group/stage/level is always accompanied by the immobility of another. While the film presents cosmopolitanism across national boundaries and includes the planet itself in the migration of humankind, it does not really take a full planetary turn, but rather stops midway. This article focuses on different forms of mobility of living organisms, resources, and energy at different levels, pointing out the film’s aestheticisation of transportation and technology-fetishism and emphasising the neglected immobility of marginalised groups, other species, and even the planet itself.

ABSTRACTThis paper focuses on the optimal control design for a system of coupled parabolic–hypebolic partial differential equations by using the infinite-dimensional state-space description and the corresponding operator Riccati equation. Some dynamical properties of the coupled system of interest are analysed to guarantee the existence and uniqueness of the solution of the linear–quadratic (LQ)-optimal control problem. A state LQ-feedback operator is computed by solving the operator Riccati equation, which is converted into a set of algebraic and differential Riccati equations, thanks to the eigenvalues and the eigenvectors of the parabolic operator. The results are applied to a non-isothermal packed-bed catalytic reactor. The LQ-optimal controller designed in the early portion of the paper is implemented for the original nonlinear model. Numerical simulations are performed to show the controller performances.

The assessment of future flood risk presented considers three climate change scenarios (a 2°C and 4°C change in Global Mean Temperature by the 2050s and 2080s and a more extreme, but plausible future, the so-called H++ future), and three population growth projections (low, high and no growth). The analysis covers the whole of the UK (England, Wales, Scotland and Northern Ireland) and the risks associated with coastal, fluvial, surface water and groundwater flooding. Eight individual Adaptation Measures (including spatial planning, flood defence, catchment storage) are used to construct five Adaptation Scenarios (including enhanced and reduced levels of adaptation ambition in comparison to present day). Future flood risks for a range of climate, population and adaptation combinations are assessed using the UK Future Flood Explorer. The analysis highlights that significant increases in flood risk are projected to occur as early as the 2020s; a finding that reinforces the need for urgent action. The analysis also highlights that to manage risk effectively under a 2 or 4°C future an enhanced whole system approach to adaptation is needed. This will require action by a broad range of stakeholders, from national level down to individual households and businesses.

Canada, like many other developed countries, has implemented a temporary foreign workers’ programme, ostensibly to address temporary labour shortages within its domestic labour market. However, there is growing evidence of the programme being used to meet longer-term labour demands, with low-skilled migrant workers being marginalized into low paying service industry jobs and manual labour in the construction and manufacturing industries. Furthermore, there is evidence of these marginalized workers suffering human rights abuses and economic exploitation. This paper discusses some of these problems and presents a case for legislative reform.

A temporal planning algorithm that is implemented on a wheeled mobile robot is presented. This algorithm has two parts: the first part is developed to control the motion of the mobile robot, and the second part is designed to control a 6-degrees-of-freedom (DOF) arm attached to the robot. In most robotic applications, it is necessary for the mobile robot to plan and follow a desired path. It may also be necessary for the robot to follow a given velocity profile, which is known as temporal planning. The advantage of temporal planning method in this paper is in its simplicity and its computational efficiency. A rudimentary trajectory is first created by assigning an arbitrary time to each segment of the path. This trajectory is made feasible by applying a number of constraints and using a linear scaling technique. When a velocity profile is given, a nonlinear time scaling technique is used to fit the mobile robot’s linear velocity to the given velocity profile. A method for avoiding moving obstacles is also implemented. Simulation and experimental results showed good agreement with each other. A novelty of this paper is in developing and implementing a new method for control of a 6-DOF arm attached to the mobile robot. Two methods have been proposed and tested for position control of the robot arm; i) linear end-effector increment (LEI), and ii) linear joints increment (LJI). It is shown that LEI is more precise than LJI in trajectory tracking of robot arm; however, the singularity of Denavit-Hartenberg (DH) transformations matrix limits the application of this method for specific trajectories. The LJI is developed to avoid the singularity in DH transformation matrix. The experimental results for four different paths show the effectiveness of the LJI approach. The successful experimental results of path and temporal planning of a wheeled mobile robot and motion control of its industrial arm is reported.

The Sherritt Zinc Pressure Leach Process has been successfully commercialized, in integration with existing roast-leach electrowin plants or replacing all the roasters and establishing direct leach-electrowin process for zinc production from the treatment of a wide variety of zinc bearing feed materials. Currently at four plants, approximately a total of 220 000 tons per year of zinc is being produced through pressure leaching and achieving elimination of about 260 000 tons per year of sulphur dioxide emission to the atmosphere. The disposal of iron bearing residues has been an integral part of zinc production since the treatment of zinc sulphide concentrates through roast-leach electrowin route started about one hundred years ago. Four iron precipitation processes have been commercialized: the jarosite process; the goethite process; the paragoethite process; and the hematite process. The paper describes the commercial applications of the Sherritt Zinc Pressure Leach Process and its integration with the commercially applied iron precipitation processes.