The invention relates to the sulfonyl esters of the general formula R1\u2014COO\u2014SO2\u2014Z\u2014R2, wherein Z, R1 and R2 are defined as in claim 1. The method of managing compute resources within a compute environment includes, based on an agreement between a compute resource provider and a customer, creating a roll-back reservation mask for compute resources which slides ahead of current time by a period of time. An open tab is formed at both ends of each of the windings. A final thin layer of high-k dielectric is formed covering the three regions, so that the region with no oxide has the thinnest dielectric layer of only high-k material and the other two regions have the high-k dielectric over SiO2 layers of different thickness. When the cover pivotally moves from the open position to the closed position, the first locking member and the second locking member engage to secure the inner body portion with cover in a closed relationship. The core material may be a light gauge rod of a plastically deformable material such as wire.