37,598 research outputs found

    FE analysis of multi-cycle micro-forming through using closed-die upsetting models and forward extrusion models

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    Research in micro-forming leads to the investigation of the effects of heat generation in the workpiece and temperature changes in the tools during the forming. The results reported in this paper relate to the study of cold micro-forming processes which are usually ignored on its thermal characteristics. Two closed-die upsetting models were used for the simulation of the forming of micro-parts in single forming trial and in mass production (multi-cycle loading), respectively. An elastic-plastic finite element simulation was performed for a single forming trial. The heat transferred to the die, computed from the simulation, was then used as an input for the multi-cycle heat loading analysis in the die. Two materials: silver and low carbon steel, were used as the work material. The results show that the die saturation temperature could still go up to 100 °C for small size dies, which is significant for the forming of micro-parts. Forming errors due to the die-temperature changes were further computed, which forms a basis for developing considerations on the forming-error compensation. Using the same methods and procedures, forming of a micro-pin via forward extrusion was analysed

    Performance-vested Stock Options and Pay-Performance Sensitivity

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    The paper investigates the incentive effects of performance-vested stock options (PVSOs) in aligning management interests with shareholder wealth. Performance targets attached to option vesting would prevent executives from receiving rewards from outcomes that are unaffected by their effort.Such targets align executive pay more closely with shareholder wealth.The degree of interest alignment is measured by pay-performance sensitivity (PPS).Using data on 4,238 executive-level observations for 1,383 executive directors in the largest 244 UK non-financial firms from 1999 to 2004, we find that the presence of PVSO schemes in executive-compensation contracts is associated with higher PPS, consistent with the idea that stronger incentives are provided by PVSOs.The empirical evidence also shows that PVSOs outperform unconditional stock options (TSOs) in providing incentives, since higher PPS is associated with the presence of PVSOs. Moreover, the results testify the role of vesting-target difficulty of PVSOs in the pay-performance relation.Specifically, difficult targets are associated with lower PPS levels, implying that too difficult targets negatively affect managers' choice of effort, that relatively lower effort is to be expected, and that the interests of managers will diverge from the interests of shareholders.stock options;pay-performance sensitivity;equity incentive
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