280 research outputs found
Impact Investing Handbook: An Implementation Guide for Practitioners
Rockefeller Philanthropy Advisors published the "Impact Investing Handbook: An Implementation Guide for Practitioners"—180 pages of helping asset owners turn interest into action. Two years in the making, this practical publication features case studies and detailed guidance for individuals, families, foundations, and corporations. Written by Steven Godeke of Godeke Consulting and Patrick Briaud of RPA, it features input from over fifty experts and practitioners.The Handbook comes at a pivotal moment. In the midst of urgent social, economic and environmental challenges including COVID-19, a rapidly changing climate, growing economic inequity, and broader realization of systemic impacts of racism, more investors are seeking to better understand the positive and negative consequences of how they deploy capital. There is a growing realization among those who seek to influence society that they can use more of their assets to complement and even accelerate their social impact goals.The Handbook covers:The Why – Developing a theory of change by merging impact goals with investment goals.The How – Building or shifting a portfolio using the full range of impact tools and structures.The So What – Measuring success through leading principles, frameworks, and standards.The Now What – Crafting a realistic implementation plan by following best practices
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A Superconducting transformer system for high current cable testing
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Characterization of High Current RRP(R) Wires as a Function of Magnetic Field, Temperature and Strain
Performance of a Nb(3)Sn Quadrupole Under High Stress
Future upgrades of the Large Hadron Collider (LHC) will require large aperture and high gradient quadrupoles. Nb(3)Sn is the most viable option for this application but is also known for its strain sensitivity. In high field magnets, with magnetic fields above 12 T, the Lorentz forces will generate mechanical stresses that may exceed 200 MPa in the windings. The existing measurements of critical current versus strain of Nb(3)Sn strands or cables are not easily applicable to magnets. In order to investigate the impact of high mechanical stress on the quench performance, a series of tests was carried out within a LBNL/CERN collaboration using the magnet TQS03 (a LHC Accelerator Research Program (LARP) 1-meter long, 90-mm aperture Nb(3)Sn quadrupole). The magnet was tested four times at CERN under various pre-stress conditions. The average mechanical compressive azimuthal pre-stress on the coil at 4.2 K ranged from 120 MPa to 200 MPa. This paper reports on the magnet performance during the four tests focusing on the relation between pre-stress conditions and the training plateau
Test results of TQS03: A LARP shell-based NbSn quadrupole using 108/127 conductor
Future insertion quadrupoles with large apertures and high gradients will be required for the Phase II luminosity upgrade (10 cms) of the Large Hadron Collider (LHC). Although improved designs, based on NbTi, are being considered as an intermediate step for the Phase I upgrade, the NbSn conductor is presently the best option that meets the ultimate performance goals for both operating field and temperature margin. As part of the development of NbSn magnet technology, the LHC Accelerator Research Program (LARP) developed and tested several 1-meter long, 90-mm aperture NbSn quadrupoles. The first two series of magnet used OST MJR 54/61 (TQ01 series) and OST RRP 54/61 (TQ02 series) strands. The third series (TQ03) used OST RRP 108/127 conductor. The larger number of sub-elements and the consequent reduction of the effective filament size, together with an increased fraction of copper and a lower Jc were expected to improve the conductor stability. The new coils were tested in the TQS03 series using a shell structure assembled with keys and bladders. The objective of the first test (TQS03a) was to evaluate the performances of the 108/127 conductor and, in particular, its behaviour at 1.9 K, while the second test (TQS03b) investigated the impact on high azimuthal pre-stress on the magnet performance. This paper reports on TQS03 fabrication, the strain gauge measurements performed during assembly, cool-down, excitation and the quench behaviour of the two magnets
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Nb3Sn for Radio Frequency Cavities
In this article, the suitability of Nb3Sn to improve theperformance of superconducting Radio-Frequency (RF)cavities is discussed.The use of Nb3Sn in RF cavitiesis recognized as an enabling technology toretain a veryhigh cavity quality factor (Q0) at 4.2 K and tosignificantly improve the cavity accelerating efficiency per unitlength(Eacc). This potential arises through the fundamental properties ofNb3Sn. The properties that are extensively characterized in theliterature are, however, mainly related to improvements in currentcarrying capacity (Jc) in the vortex state. Much less is available forthe Meissner state, which is of key importance to cavities. Relevantdata, available for the Meissner state is summarized, and it is shown howthis already validates the use of Nb3Sn. In addition, missing knowledgeis highlighted and suggestions are given for further Meissner statespecific research
Advances in NbSn performance
NbSn wires with non-Cu critical current densities (Jc) that surpass 3 kAmm−2 at 12 T and 4.2 K are commercially available in piece lengths longer than 10 km. Acceleratortype magnets that utilize these conductors have achieved record magnetic fields. This article summarizes key developments in the last decade that have led to these significant improvements in the performance of NbSn wires
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