Research Part Surface Position Influence on Metal Removal and Steady-State Roughness During Vibro-Abrasive Processing

The paper is devoted to the study of part surface position and its influence on metal removal and steady-state rougness during vibro-abrasive processing. The article raises the differences between vibro-abrasive processing of external and internal part surfaces. Theoretical dependencies analysis for determination on part material removal and surface steady-state roughness is carried out. It is known that available theoretical dependencies do not take into account part surface position for material removal and the steady-state roughness calculation. Experimental researches to determine internal surface material removal with external surface isolation were carried out. The influence of part surface position on the steady-state roughness is investigated. Based on obtained experimental results, the dependence graphs of material removal and roughness on the processing time are constructed. The comparative analysis of the part surface position influence on material removal and the steady-state roughness during vibro-abrasive processing is carried out. The results showed that material removal volume from the internal surface more than from the external for short part length, however material removal volume from the external surfaces grows significantly in case of part length increasing, while from the internal surfaces is not significant. It is established that the internal surface steady-state roughness is ∼1.55 times higher than external surface steady-state roughness after processing in triangular prism 15×15, grit 16.

A technology for seabed installation of an underwater massive tank

This paper attempts to determine the law of motion of a tank as a large volumetric massive structure when immersed in a resisting liquid medium. The authors propose two methods for its determination. Dependence graphs of coordinates, speed, acceleration of the tank versus time are plotted. The dependence of time and speed of lowering of a massive storage structure on the volume of pumped water is determined. In addition, the range of the optimal volume of water pumped inside the tank for the purpose of its soft landing is determined.

A generic approach to scheduling and checkpointing workflows

This work deals with scheduling and checkpointing strategies to execute scientific workflows on failure-prone large-scale platforms. To the best of our knowledge, this work is the first to target fail-stop errors for arbitrary workflows. Most previous work addresses soft errors, which corrupt the task being executed by a processor but do not cause the entire memory of that processor to be lost, contrarily to fail-stop errors. We revisit classical mapping heuristics such as Heterogeneous Earliest Finish Time and MinMin and complement them with several checkpointing strategies. The objective is to derive an efficient trade-off between checkpointing every task (CkptAll), which is an overkill when failures are rare events, and checkpointing no task (CkptNone), which induces dramatic re-execution overhead even when only a few failures strike during execution. Contrarily to previous work, our approach applies to arbitrary workflows, not just special classes of dependence graphs such as minimal series-parallel graphs. Extensive experiments report significant gain over both CkptAll and CkptNone for a wide variety of workflows.

Selection of Complete Recovery of Precious Metals in the Processing of Copper-Nickel Alloys in Hydrometallurgical Way

This article deals with the key aspects of how to determine the dissolution potential of copper-nickel base alloys containing precious metals in a lab environment and select conditions for their dissolution. The work indicates the composition of the anode under research and presents the dependence graphs of the potentials on time and stress. It also explains the effect of some impurities on the process.