Mechanical Control of Individual Superconducting Vortices

Plantation forests certified by the Forest Stewardship Council have restrictions on herbicide use. Since certified plantations are dependant on herbicides for cost-effective vegetation management, compliance requires a shift from current chemical practices. Using New Zealand plantation forests as a case study, discounted cash flow analyses were used to estimate the cost of certification-compliant vegetation control regimes compared with current non-compliant methods. We examined methods that (i) reduce the quantity of herbicides by using spot control and (ii) avoid the use of herbicides by using weed mats, manual, and mechanical control. Cost analyses were undertaken for low-, medium-, and high-productivity sites. The internal rate of return of the non-compliant regime was between 5% and 5.8% across the productivity range. Spot control was cheaper than current non-compliant practice. However, spot control is limited by site suitability and the availability of labour. Non-chemical control methods were expensive relative to other regimes. Reductions in the internal rate of return varied across low- and high-productivity sites between 0.8% and 0.5% for manual control, 1.3% and 0.8% for mechanical control, and 1.7% and 1.0% for weed mats. Meeting the goals of certification while retaining cost-effective vegetation control presents a challenge to the plantation forestry sector.

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Welding thermal cycle-triggered precipitation processes in steel S700MC subjected to the thermo-mechanical control processing

Archives of Metallurgy and Materials ◽

10.1515/amm-2017-0048 ◽

2017 ◽

Vol 62 (1) ◽

pp. 321-326 ◽

Cited By ~ 13

Author(s):

J. Górka

Keyword(s):

Thermomechanical Processing ◽

Control Process ◽

Base Material ◽

Structural Defects ◽

Accelerated Cooling ◽

Internal Stresses ◽

Mechanical Control ◽

Thin Foils ◽

Precipitation Processes ◽

The Matrix

Abstract This study presents tests concerned with welding thermal process-induced precipitation processes taking place in 10 mm thick steel S700MC subjected to the Thermo-Mechanical Control Process (TMCP) with accelerated cooling. The thermomechanical processing of steel S700MC leads to its refinement, structural defects and solutioning with hardening constituents. Tests of thin foils performed using a transmission electron microscope revealed that the hardening of steel S700MC was primarily caused by dispersive (Ti,Nb)(C,N) precipitates (being between several and less than twenty nanometers in size). In arc welding, depending on a welding method and linear energy, an increase in the base material in the weld is accompanied by the increased concentration of hardening microagents in the weld. The longer the time when the base material remains in the liquid state, the greater the amount of microagents dissolved in the matrix. During cooling, such microagents can precipitate again or remain in the solution. An increase in welding linear energy is accompanied by an increase in the content of hardening phases dissolved in the matrix and, during cooling, by their another uncontrolled precipitation in the form of numerous fine-dispersive (Ti,Nb)(C,N) precipitates of several nm in size, leading to a dislocation density increase triggered by type 2 internal stresses.

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