Modeling heat transfer from quench protection heaters to superconducting cables in Nb3Sn magnets

We use a recently developed quench protection heater modeling tool for an analysis of heater delays in superconducting high-field Nb3Sn accelerator magnets. The results suggest that the calculated delays are consistent with experimental data, and show how the heater delay depends on the main heater design parameters.Comment: 8 pages, Contribution to WAMSDO 2013: Workshop on Accelerator Magnet, Superconductor, Design and Optimization; 15 - 16 Jan 2013, CERN, Geneva, Switzerlan

Anatomically Constrained Video-CT Registration via the V-IMLOP Algorithm

Functional endoscopic sinus surgery (FESS) is a surgical procedure used to treat acute cases of sinusitis and other sinus diseases. FESS is fast becoming the preferred choice of treatment due to its minimally invasive nature. However, due to the limited field of view of the endoscope, surgeons rely on navigation systems to guide them within the nasal cavity. State of the art navigation systems report registration accuracy of over 1mm, which is large compared to the size of the nasal airways. We present an anatomically constrained video-CT registration algorithm that incorporates multiple video features. Our algorithm is robust in the presence of outliers. We also test our algorithm on simulated and in-vivo data, and test its accuracy against degrading initializations.Comment: 8 pages, 4 figures, MICCA

A note using mergers and acquisitions to gain competitive advantage in the United States in the case of Latin American MNCs

Author's OriginalThe "new" economic and business climate in Latin America, fostered by multilateral trade agreements such as NAFTA, MERCOSUR, and the ANDEAN Pact, suggests that Latin American (LA) firms must become more aggressive and competitive in order to survive. Foreign direct investment in the form of mergers and acquisitions (M&A) is often an effective way of competing in a tough global environment. Using transactions data collected from Security Data Company's Worldwide Merger and Acquisition database, this paper analyzes the relative involvement of firms from five LA countries (Argentina, Brazil, Chile, Mexico, and Venezuela) in acquiring targets in the United States of America. Transaction characteristics examined and summarized include the annual distribution (1985-1998) of the deals, the industrial sector of the target firm, the form of acquisition method used, and the form of ownership of the target firm. The trends are analyzed, and implications for managers are indicated.Milman, C. D., D’Mello, J. P., Aybar, B., & Arbaláez, H. (2001). A note using mergers and acquisitions to gain competitive advantage in the United States in the case of Latin American MNCs. International Review of Financial Analysis, 10(3), 323-332. doi:10.1016/S1057-5219(01)00056-

Error analysis for hybrid undulators

A general modeling framework is introduced that allows for the solution to magnetic field perturbations due to mechanical and magnetic tolerances in hybrid undulators. For example, both geometric pole errors and permanent magnet block geometry and strength errors can be considered. Of particular significance is the scaling of the various errors with variations in the gap of the device. In this work, the perturbation analysis is presented along with specific examples of errors found in hybrid undulators

Conceptual design of storage ring magnets for a diffraction limited light source upgrade of ALS, ALS-U

Lawrence Berkeley National Laboratory (LBNL) has been engaged in an internal laboratory directed research and development project to define a suitable accelerator physics lattice to support the diffraction limited upgrade of the Advanced Light Source (ALS). [1] Diffraction limited lattices require strong focusing elements throughout. Magnetics design is challenging in that the high gradient magnetic structures are required to operate in close proximity. Lattice development requires a coordinated engineering design effort to ensure the lattice design feasibility. We will present a review of the results of our magnet scoping studies as well as conceptual design specifications for the ALS-U lattice dipole, quadrupole, and sextupole magnet systems

Access and metro network convergence for flexible end-to-end network design

This paper reports on the architectural, protocol, physical layer, and integrated testbed demonstrations carried out by the DISCUS FP7 consortium in the area of access - metro network convergence. Our architecture modeling results show the vast potential for cost and power savings that node consolidation can bring. The architecture, however, also recognizes the limits of long-reach transmission for low-latency 5G services and proposes ways to address such shortcomings in future projects. The testbed results, which have been conducted end-to-end, across access - metro and core, and have targeted all the layers of the network from the application down to the physical layer, show the practical feasibility of the concepts proposed in the project

Mechanical Study of a Superconducting 28-GHz Ion Source Magnet for FRIB

The superconducting electron cyclotron resonance (ECR) source magnet for the facility for rare isotope beams at Michigan State University was designed and built by the Superconducting Magnet Group at Lawrence Berkeley National Laboratory (LBNL) in 2017. The 28 GHz NbTi ion source magnet features a sextupole-in-solenoids configuration which is comparable to the VENUS ECR magnet operated at LBNL. However, the mechanical design of this magnet utilizes a shell-based support structure which allows fine adjustments to the sextupole preload and reversibility of the magnet assembly process. The magnet has been assembled and tested to operational currents at LBNL. This paper describes the mechanical analyses performed to estimate the sextupole's and solenoids' preloads. We will report on the 3-D finite element analysis during room temperature assembly, cool-down, and magnet excitation, and then describe the magnet preload operations. Finally, we will describe the performance of the support structure during the quench training

Changes in the nocturnal activity of birds during the COVID-19 pandemic lockdown in a neotropical city

Changes in the nocturnal activity of birds during the COVID-19 pandemic lockdown in a neotropical city. The COVID-19 lockdown provided the opportunity to measure species biodiversity in urban environments under conditions divergent from regular urban rhythms. For 90 days, including weeks of strict lockdown and the subsequent relaxation of restrictions, we measured the presence and abundance of birds that were active at night at two sites in the city of Cali, Colombia. Our results show that species richness of nocturnal birds decreased 40% to 58% during the weeks with more human activity, adding further evidence to the biodiversity responses of the 'anthropause' on urban environments.Non peer reviewe