Finite-element analysis of the strain distribution due to bending in a REBCO coated conductor for canted cosine theta dipole magnet applications

High-current cables using REBCO tapes can be used to develop high-field dipole magnets. However, the strain accumulated during cable fabrication and coil winding may reduce the critical current of the conductor. Therefore, it is important to properly consider the strain when designing high-field magnets. In this paper, we used structural finite-element analysis (FEA) to predict the strain experienced by a REBCO tape during bending in configurations relevant to the fabrication of high-field accelerator magnets, in particular, the mechanical strain generated during cable fabrication and winding in a canted-cosθ dipole configuration. We considered two different cable options: (A) Flat tape that lay in the mandrel channel and (B) a REBCO tape helically wound around a circular copper core, the typical configuration of the conductor in round core cable (CORC). Strain accumulated during tape winding is studied for different core diameters and winding tilt angles. FEA longitudinal strain results were compared with the simulations for configuration A, where higher strain was observed experimentally. Configuration B was verified indirectly by comparing experimentally measured I with the one predicted (based on the longitudinal strain) as a function of the bending diameter. Good agreement was found up to a bending diameter of 30 mm. The presented results will help to understand the impact of bending on REBCO tapes and CORC wires to develop high-field magnets.

Case to Cause: Back to the Future

This article reopens the historic debate about the roles of micro and macro practice in social work and encourages the profession to find ways to achieve a better balance between case and cause in education, practice, and research. To this end, it traces the history of the case versus cause debate including conceptual frameworks for rebalancing social work education: Bertha Capen Reynolds, C. Wright Mills, and William Schwartz, highlights three alternative approaches for resolving the dualism put forward over the years; separation, merger and interconnection; and identifies four model that help to bridge the gap by taking both the individual and the social structures into account: ecological, financial capabilities, trauma theory and oppression. This historical analysis offers promising directions for the social work profession as it tackles 21st–century social challenges, including growing inequality and austerity–driven public policies

POLICY-MAKING IN THE AMERICAN STATES: TYPOLOGY, PROCESS, AND INSTITUTIONS

The three levels of government in the U.S. federal system maintain a different set of policy priorities because they operate under varying environmental constraints and resources. Efforts to categorize and specify the politics in terms of policy types have been particularly fruitful at both the federal (e.g., Lowi) and the local (e.g., Peterson) levels. At the state level, however, the typology perspective has yet to be more fully developed. This paper makes a preliminary effort to construct a typology framework in understanding state politics and policy. First, politics can be differentiated between growth and redistribution in the structural economic context. While redistributive politics are largely structured by class-oriented issues, growth politics are predominantly shaped by territorial concerns that temper class and ideological differences. Equally important, the growth-redistribution distinction can be supplemented by the politics of routine services, such as public education. The latter remains dominated by service-provider groups. Moreover, based on an empirical analysis of hundreds of bills in one state legislature, these political differences are found to have contributed to variations in policy consensus among lawmakers as well as interest group representation in agenda setting and legitimation across policy arenas. Our findings also suggest limitations to the typology framework. Copyright 1989 by The Policy Studies Organization.