Dynamic Characteristics of Lifting Pipe on a Retrofitted Mining Vessel

Lifting pipe used in deep ocean mining is the tool to transport mineral from seabed to vessel. In this study, a vessel was retrofitted as an experimental ship for deep ocean mining with a U-type lifting pipe installed on the right side of vessel. Assuming pipe as a rigid structure, the impact of pipe on movements of vessel were discussed based on frequency domain method for hydrodynamic analysis.

Comparative Analysis of Longitudinal and Transverse Vibration Characteristics of Ocean Mining Pipe

In this paper, the 5000 m mining pipe is taken as the research object, and the transverse and longitudinal vibration laws of the pipe under different working conditions are analyzed. Based on the finite element method (FEM), the pipe is discretized and calculated by the Wilson-θ Wilson - θ integral method; finally, the corresponding vibration laws of the mining pipe are obtained. The research shows that the mining pipe vibration responses are irregular motion, with the obvious oscillation phenomenon, and the overall vibration trend decreases first and then increases from the top to the bottom; the maximum vibration response occurs at the pipe top. Under the same working conditions, increasing the towing velocity will decrease the overall longitudinal vibration amplitude and increase the overall transverse vibration amplitude. While the ore bin weight will increase the longitudinal vibration amplitude and decrease the transverse vibration amplitude, increasing the mining pipe large diameter stepped section length and damping will decrease the longitudinal and transverse vibration simultaneously. When the towing velocity is between 0–2.8 m/s, the longitudinal vibration intensity is large, which is the main vibration mode. When the towing velocity is 2.8 m/s, the critical point is reached, and the longitudinal and transverse vibrations have the same intensity. When the towing velocity is greater than 2.8 m/s, the transverse vibration intensity is gradually greater than the longitudinal vibration intensity; at this time, the control of the transverse vibration should be appropriately increased.

Research of Particle Motion in a Two-Stage Slurry Transport Pump for Deep-Ocean Mining by the CFD-DEM Method

The slurry transport pump is the key equipment of deep-ocean mining systems. The motion law of coarse particles in the pump is not clear enough. In this paper, a hydraulic model of a laboratory-scale two-stage slurry transport pump is constructed, and the motion characteristics of coarse particles in the pump are numerically studied by using the computational fluid dynamics–discrete element method (CFD-DEM) method. The performance curve of the pump is obtained by experimental measurement, and the reliability of the calculated results is verified. Due to the application of the amplification flow rate design method, the optimum efficiency point of the pump is shifted to the large flow rate condition. Differences in particle swarm within two stages are compared. The position distribution, velocity variation and trajectory of particles in the impeller and bowl diffuser are studied in detail. The velocity of particles leaving the impeller depends on whether they collide with the impeller blade. The motion of particles in the bowl diffuser is divided into three periods. Collision between particles and blades in the bowl diffuser not only leads to energy loss but also gradually transforms the circumferential velocity of particles into axial velocity in the second period. This work can provide a reference for the study of wear and blockage prevention of slurry transport pumps.

Geoethics as global ethics to face grand challenges for humanity

Geoethics is not simply professional ethics. Originally, it was developed in the context of geosciences to increase the awareness of geoscientists to their cultural and social role, but over time expanded to define a way in which humans can rethink their relationship with the Earth system in the light of principles and values that can provide a healthy and safe life in respect for geo-ecosystems. The theoretical framework of geoethics has now consolidated, and it has become the proposal on which to base a global ethics for the new millennium. This chapter outlines the scientific and cultural reference framework in which geoethics developed; the theoretical foundations of geoethics and its main characteristics; global anthropogenic issues under a geoethical perspective; ethical and social aspects related to two potential human activities respectively to combat global warming (geoengineering); and to provide for the growing demand for georesources (deep-sea/ocean mining). The authors highlight the importance of sharing values and actions among planetary human communities to manage global changes and threats. One wonders if the SARS-CoV-2 pandemic can suggest or confirm reflections on geoethical thinking. Finally, a charter for a responsible course of human development, articulated in nine principles and actions, is proposed.